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Sample records for antimon och ett

  1. Electrochemical reaction of lithium with nanosized vanadium antimonate

    SciTech Connect

    Morales, Julian; Sanchez, Luis . E-mail: luis-sanchez@uco.es; Martin, Francisco; Berry, Frank

    2006-08-15

    Nanometric vanadium antimonate, VSbO{sub 4}, was prepared by mechanical milling from Sb{sub 2}O{sub 3} and V{sub 2}O{sub 5} and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Mossbaueer spectroscopy (MS) and X-ray photoelectron spectroscopy (XPS) techniques. Its reactivity towards lithium was examined by testing Li/VSbO{sub 4} cells under galvanostatic and potentiostatic regimes. The amount of Li inserted was found to be consistent with a two-step process involving the reactions (i) VSbO{sub 4}+8 Li{sup {yields}}Sb+V+4 Li{sub 2}O and (ii) Sb+3 Li{sup {yields}}Li{sub 3}Sb, the former being virtually irreversible and the latter reversible as suggested by the shape of the anodic and cathodic curves. Ex situ XPS measurements of the discharged and charged electrode provided direct evidence of the formation of alloyed Sb and confirmed the results of the potentiostatic curves regarding the irreversible or reversible character of the previous reactions. The Li/VSbO{sub 4} cell exhibited acceptable electrochemical performance, which surpassed that of other Sb-based compounds as the likely result of the formation of V and its associated enhanced electrode conductivity. - Graphical abstract: TEM image of nanosized VSbO{sub 4} sample.

  2. Abiotic Reduction of Selenite and Antimonate Under Controlled Oxygen Conditions

    NASA Astrophysics Data System (ADS)

    Belzile, N.; Truong, H. T.; Polack, R.; Chen, Y.

    2008-12-01

    Laboratory and field studies have reported the oxidation of elemental Se to selenite or selenate or that of antimonite to antimonate but the reduction studies of the two elements, especially in absence of bacteria are more scarce. We have performed experiments on the abiotic reduction of Se(IV) and Sb(V) under controlled oxygen conditions in presence of naturally-encountered reducing agents such as Fe(II) and dissolved sulfide. In the case of selenite, the reduction by ferrous iron is barely detectable at very low concentrations of oxygen. However, at concentrations of 200 ± 50 ppmv in the controlled atmosphere glove box, more iron oxide particles were formed at a higher initial Fe(II) concentration in the system and with time. In the pellets collected after filtration, a significant amount of Se(0) was found. Our field geochemical studies on Se also showed the same phenomenon, i.e. a higher level of Se(0) in lake sediments was accompanied by a higher presence of iron oxides. In the case of antimony, the reduction of Sb(V) by dissolved sulfide was extensive and far more rapid at more acidic pH values. Half lives for Sb(V) in the presence of excess dissolved sulfide at pH values of 5 to 7 were calculated and the reaction was found to be first order with respect to all three of [Sb(V)], [dissolved sulfide] and [H+]. Metastibnite precipitated after reduction of Sb(V) in working experimental samples at buffered pH of 5 and 6. The oxidation product of dissolved sulfide was identified as elemental sulfur. This study has demonstrated the ability of dissolved sulfide to reduce Sb(V) under a variety of environmentally relevant concentrations and conditions.

  3. Study of the redox properties of bismuth-molybdate and uranium-antimonate catalysts

    SciTech Connect

    Paz-Pujalt, G.R.

    1985-01-01

    The oxidation/reduction properties of various bismuth molybdates, molybdenum trioxide, bismuth oxide, uranium antimonate, and iron antimonate have been studied in an effort to correlate them to their catalytic properties. The temperature at which ..gamma..-phase bismuth molybdate is prereduced plays an important role in the behavior the catalyst exhibits under reoxidation conditions. The overall behavior of ..gamma..-phase bismuth molybdate under catalytic conditions may be divided into two temperature regimes: below 360/sup 0/C the catalyst shows a higher rate of propylene adsorption than product desorption, and above 360/sup 0/C where produced desorption is dominant. This temperature is the same at which the Arrhenius plot for the reaction has a break. Several reduction of ..gamma..-bismuth molybdate results in the formation of clusters of bismuth metal and crystallites of molybdenum dioxide. This is irreversible. The reoxidation of the bismuth molybdate catalysts shows the presence of two oxygen incorporation temperatures. The ratios of the areas under these peaks are not the same for the three catalysts. Uranium antimonate shows a lesser degree of lattice oxygen participation. During several reduction the catalyst decomposes partially and an excess of antimony is evident. The isothermal reduction profiles of the catalysts permitted their classification into either of two reduction models: (A) ..cap alpha..-, ..beta..-, ..gamma..-phase bismuth molybdates, molybdenum trioxide, bismuth oxide, and the equimolar mixture follow the nucleation model, (B) uranium antimonate, and iron antimonate following the shrinking sphere model. These models have been correlated to certain characteristics of these catalysts. Group A catalysts show a high degree of lattice oxygen participation (migration of bulk oxygen to surface nuclei). In contrast in group B catalysts only a few layers of oxygen are peeled off during catalysis.

  4. Quantitative separation of Hg(II) from several metal ions on Zr(IV) antimonate papers

    SciTech Connect

    Seth, N.S.; Rajput, R.P.S.; Agrawal, N.K.; Agrawal, S.K.; Agrawal, S.

    1985-09-01

    The chromatographic behavior of 32 metal ions has been studied on paper impregnated with Zirconium(IV) antimonate in aqueous HCl and mixed solvent system containing dimethylsulfoxide and dioxane. Several important binary and ternary separations have been achieved. Quantitative separation of Hg(II) from NiS , PbS , PdS , RuT , RhT , BiT , CoS , CdS and GdT is described. 6 references, 3 tables.

  5. Dissimilatory antimonate reduction and production of antimony trioxide microcrystals by a novel microorganism.

    PubMed

    Abin, Christopher A; Hollibaugh, James T

    2014-01-01

    Antimony (Sb) is a metalloid that has been exploited by humans since the beginning of modern civilization. The importance of Sb to such diverse industries as nanotechnology and health is underscored by the fact that it is currently the ninth-most mined metal worldwide. Although its toxicity mirrors that of its Group 15 neighbor arsenic, its environmental chemistry is very different, and, unlike arsenic, relatively little is known about the fate and transport of Sb, especially with regard to biologically mediated redox reactions. To further our understanding of the interactions between microorganisms and Sb, we have isolated a bacterium that is capable of using antimonate [Sb(V)] as a terminal electron acceptor for anaerobic respiration, resulting in the precipitation of antimonite [Sb(III)] as microcrystals of antimony trioxide. The bacterium, designated strain MLFW-2, is a sporulating member of a deeply branching lineage within the order Bacillales (phylum Firmicutes). This report provides the first unequivocal evidence that a bacterium is capable of conserving energy for growth and reproduction from the reduction of antimonate. Moreover, microbiological antimonate reduction may serve as a novel route for the production of antimony trioxide microcrystals of commercial significance to the nanotechnology industry.

  6. Synthesis of calcium antimonate nano-crystals by the 18th dynasty Egyptian glassmakers

    NASA Astrophysics Data System (ADS)

    Lahlil, S.; Biron, I.; Cotte, M.; Susini, J.; Menguy, N.

    2010-01-01

    During the 18th Egyptian dynasty (1570-1292 B.C.), opaque white, blue and turquoise glasses were opacified by calcium antimonate crystals dispersed in a vitreous matrix. The technological processes as well as the antimony sources used to manufacture these crystals remain unknown. Our results shed a new light on glassmaking history: contrary to what was thought, we demonstrate that Egyptian glassmakers did not use in situ crystallization but first synthesized calcium antimonate opacifiers, which do not exist in nature, and then added them to a glass. Furthermore, using transmission electron microscopy (TEM) for the first time in the study of Egyptian opaque glasses, we show that these opacifiers were nano-crystals. Prior to this research, such a process for glassmaking has not been suggested for any kind of ancient opaque glass production. Studying various preparation methods for calcium antimonate, we propose that Egyptian craftsmen could have produced Ca2Sb2O7 by using mixtures of Sb2O3 or Sb2O5 with calcium carbonates (atomic ratio Sb/Ca=1) heat treated between 1000 and 1100°C. We developed an original strategy focused on the investigation of the crystals and the vitreous matrices using an appropriate suite of high-sensitivity and high-resolution micro- and nano-analytical techniques (scanning electron microscopy (SEM), X-ray diffraction (XRD), TEM). Synchrotron-based micro X-ray absorption near edge spectroscopy (μ-XANES) proved to be very well suited to the selective measure of the antimony oxidation state in the vitreous matrix. This work is the starting point for a complete reassessment not only of ancient Egyptian glass studies but more generally of high-temperature technologies used throughout antiquity.

  7. Antimony uptake, translocation and speciation in rice plants exposed to antimonite and antimonate.

    PubMed

    Ren, Jing-Hua; Ma, Lena Q; Sun, Hong-Jie; Cai, Fei; Luo, Jun

    2014-03-15

    Antimony (Sb) accumulation in rice is a potential threat to human health, but its uptake mechanisms are unclear. A hydroponic experiment was conducted to investigate uptake, translocation, speciation and subcellular distribution of Sb in rice plants exposed to antimonite (SbIII) and antimonate (SbV) at 0.2, 1.0 or 5.0 mg/L for 4h. More Sb was accumulated in iron plaque than in the plant, with both the roots (~10-12 times) and Fe plaque (~28-54 times) sequestering more SbIII than SbV. The presence of iron plaque decreased uptake of both SbV and SbIII. SbIII uptake kinetics fitted better to the Michaelis-Menten function than SbV. Antimonate (56 to 98%) was the predominant form in rice plant with little methylated species being detected using HPLC-ICP-MS. Cell walls accumulated more Sb than organelles and cytosol, which were considered as the first barrier against Sb entering into cells. Sb transformation and subcellular distribution can help to understand the metabolic mechanisms of Sb in rice.

  8. OCH Strap Model Test

    SciTech Connect

    Weber, K.; /Fermilab

    1987-08-26

    The OCH Model was stacked using the appropriate spacers between each absorber plate. Steel bars measuring 3-inch wide by 1/4-inch thick were welded, using 1/8-inch fillet weld, along all the corner edges, except the outer radius edges. On the outer radius, the straps were bolted to the end plates and to plates 9 and 17. The straps on the outer radius were also set in towards the center by approximately 3-inches. The spacers were then knocked out. Twelve strain gauges were mounted on the model. See figure 1 and the OCH strap Model log book for locations. Each rosette was centered in the gap between two absorber plates. The finite element plate model can predict the primary deformations of the OH module in both the cantilever and crushing modes to within 11% of the measured values. The primary stresses away from the support plate for the cantilever mode can be predicted to within 13% by this model. Near the support plate where large shear stresses exists, ANSYS will overpredict the measured stresses substantially. This is probably due to the models inherent inability to allow for shear stress concentrations at the welds. The same over-prediction was seen in the side straps during the OH crush test comparison and is probably attributable to the high shear force in this mode. The simple finite element plate model will provide suitable model of OH module stiffness for use in the analysis of the module assembly. The calculation of shear stresses can be improved by applying the ANSYS calculated inter-element forces to traditional weld strength calculations

  9. OCH Button Test

    SciTech Connect

    Kurita, C.H.; /Fermilab

    1987-05-01

    A test was conducted to make a check on the yield stress of the copper spacer buttons to be used in OCH. The tested button was made from Copper no. 110, cold drawn rod, which has a documented yield stress value of 48,000 psi. The button was put into compression with the load applied to the face of the button. The resulting deflection vs. the applied cross load was then charted with the width of the chart having a 10,000 kg scale. While the chart speed was set at 1 cm/min, the cross head speed was set at .05 cm/min. To find a value of Young's Modulus for the OCH button, the compression test was run again with a chart width scale of 5,000 kg. The chart speed was set at 10 cm/min and the cross head speed at .05 cm/min. The curve generated on the chart was linear in nature until the button reached its yield point. Here, the slope of the curve began to change, increasing over a small area until a new linear curve was established. The point at which the slope changed would be considered the yielding point of the material, but here, there was no single distinct point. Instead there was a smooth transition between the two linear portions of the curve. In order to find where the yield point would occur, two lines were drawn, representing the best fit of each of the two slopes of the curve (before and after the yield point). The intersection of these lines was taken to be the point from which the yield stress could be calculated.

  10. Autotrophic antimonate bio-reduction using hydrogen as the electron donor.

    PubMed

    Lai, Chun-Yu; Wen, Li-Lian; Zhang, Yin; Luo, Shan-Shan; Wang, Qing-Ying; Luo, Yi-Hao; Chen, Ran; Yang, Xiaoe; Rittmann, Bruce E; Zhao, He-Ping

    2016-01-01

    Antimony (Sb), a toxic metalloid, is soluble as antimonate (Sb(V)). While bio-reduction of Sb(V) is an effective Sb-removal approach, its bio-reduction has been coupled to oxidation of only organic electron donors. In this study, we demonstrate, for the first time, the feasibility of autotrophic microbial Sb(V) reduction using hydrogen gas (H2) as the electron donor without extra organic carbon source. SEM and EDS analysis confirmed the production of the mineral precipitate Sb2O3. When H2 was utilized as the electron donor, the consortium was able to fully reduce 650 μM of Sb(V) to Sb(III) in 10 days, a rate comparable to the culture using lactate as the electron donor. The H2-fed culture directed a much larger fraction of it donor electrons to Sb(V) reduction than did the lactate-fed culture. While 98% of the electrons from H2 were used to reduce Sb(V) by the H2-fed culture, only 12% of the electrons from lactate was used to reduce Sb(V) by the lactate-fed culture. The rest of the electrons from lactate went to acetate and propionate through fermentation, to methane through methanogenesis, and to biomass synthesis. High-throughput sequencing confirmed that the microbial community for the lactate-fed culture was much more diverse than that for the H2-fed culture, which was dominated by a short rod-shaped phylotype of Rhizobium (α-Protobacteria) that may have been active in Sb(V) reduction.

  11. Vibrational spectroscopic study of the antimonate mineral bindheimite Pb 2Sb 2O 6(O,OH)

    NASA Astrophysics Data System (ADS)

    Bahfenne, Silmarilly; Frost, Ray L.

    2009-09-01

    Raman spectroscopy complimented with infrared spectroscopy has been used to characterise the antimonate mineral bindheimite Pb 2Sb 2O 6(O,OH). The mineral is characterised by an intense Raman band at 656 cm -1 assigned to SbO stretching vibrations. Other lower intensity bands at 664, 749 and 814 cm -1 are also assigned to stretching vibrations. This observation suggests the non-equivalence of SbO units in the structure. Low intensity Raman bands at 293, 312 and 328 cm -1 are assigned to the OSbO bending vibrations. Infrared bands at 979, 1008, 1037 and 1058 cm -1 may be assigned to δOH deformation modes of SbOH units. Infrared bands at 1603 and 1640 cm -1 are assigned to water bending vibrations, suggesting that water is involved in the bindheimite structure. Broad infrared bands centred upon 3250 cm -1 supports this concept. Thus the true formula of bindheimite is questioned and probably should be written as Pb 2Sb 2O 6(O,OH,H 2O).

  12. A new strontium antimonate{sup III} Sr{sub 5}Sb{sub 22}O{sub 38}: Synthesis, crystal structure and characterizations

    SciTech Connect

    Geng, Lei; Meng, Chang-Yu; Lin, Chen-Sheng; Cheng, Wen-Dan

    2013-07-15

    A new strontium antimonate{sup III}, Sr{sub 5}Sb{sub 22}O{sub 38}, has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. It crystallizes in the P2{sub 1}/n space group of the monoclinic system with a=11.739(9) Å, b=12.014(10) Å, c=16.412(13) Å, β=91.460(8)°, V=2314.0(3) Å{sup 3}. The crystal structure is built of seven trigonal–pyramidal SbO{sub 3} and four sphenoid SbO{sub 4} polyhedra which are connected through sharing corner-oxygen atoms to form the complex three-dimensional {sub ∞}{sup 3}[Sb{sub 22}O{sub 38}]{sup 10−} anionic network with two different intersectant tunnels along the [111-bar ] and [11-bar 1-bar ] directions accommodating the electric charge balanced Sr{sup 2+} cations. First-principles electronic structure calculations based on the density functional theory (DFT) and the UV–vis diffuse reflectance spectroscopy measurements both indicate that the compound belongs to a direct band insulator with an optical gap value of 3.3 eV. - Graphical abstract: The 2D Sb–O slabs are stacked through sharing oxygen atoms to form the 3D network structure of the new strontium antimonate{sup III} Sr{sub 5}Sb{sub 22}O{sub 38}. - Highlights: • A new strontium antimonate{sup III}, Sr{sub 5}Sb{sub 22}O{sub 38}, has been hydrothermally synthesized. • The single crystal structure was determined by X-ray diffraction. • The powder XRD and UV–vis absorption spectroscopy were studied. • Theoretical studies interpret the relationships between optical absorption and crystal structure.

  13. Crystallization and preliminary crystallographic characterization of LmACR2, an arsenate/antimonate reductase from Leishmania major

    SciTech Connect

    Bisacchi, Davide; Zhou, Yao; Rosen, Barry P.; Mukhopadhyay, Rita; Bordo, Domenico

    2006-10-01

    LmACR2 from L. major is the first rhodanese-like enzyme directly involved in the reduction of arsenate and antimonate to be crystallized. Diffraction data have been collected to 1.99 Å resolution using synchrotron X-rays. Arsenic is present in the biosphere owing either to the presence of pesticides and herbicides used in agricultural and industrial activities or to leaching from geological formations. The health effects of prolonged exposure to arsenic can be devastating and may lead to various forms of cancer. Antimony(V), which is chemically very similar to arsenic, is used instead in the treatment of leishmaniasis, an infection caused by the protozoan parasite Leishmania sp.; the reduction of pentavalent antimony contained in the drug Pentostam to the active trivalent form arises from the presence in the Leishmania genome of a gene, LmACR2, coding for the protein LmACR2 (14.5 kDa, 127 amino acids) that displays weak but significant sequence similarity to the catalytic domain of Cdc25 phosphatase and to rhodanese enzymes. For structural characterization, LmACR2 was overexpressed, purified to homogeneity and crystallized in a trigonal space group (P321 or P3{sub 1}21/P3{sub 2}21). The protein crystallized in two distinct trigonal crystal forms, with unit-cell parameters a = b = 111.0, c = 86.1 Å and a = b = 111.0, c = 175.6 Å, respectively. At a synchrotron beamline, the diffraction pattern extended to a resolution limit of 1.99 Å.

  14. Uptake of antimonite and antimonate by arsenic hyperaccumulator Pteris vittata: Effects of chemical analogs and transporter inhibitor.

    PubMed

    Tisarum, Rujira; Chen, Yanshan; Dong, Xiaoling; Lessl, Jason T; Ma, Lena Q

    2015-11-01

    Antimonite (SbIII) is transported into plants via aquaglyceroporin channels but it is unknown in As-hyperaccumulator Ptreis vittata (PV). We tested the effects of SbIII analogs (arsenite-AsIII, glycerol, silicic acid-Si, and, glucose), antimonate (SbV) analog (phosphate-P), and aquaglyceroporin transporter inhibitor (silver, Ag) on the uptake of SbIII or SbV by PV gametophytes. PV gametophytes were grown in 20% Hoagland solution containing 65 μM SbIII or SbV and increasing concentrations of analogs at 65-6500 μM for 2 h or 4 h under sterile condition. After exposing to 65 μM Sb for 2 h, PV accumulated 767 mg/kg Sb in SbIII treatment and 419 mg/kg in SbV treatment. SbIII uptake by PV gametophytes was not impacted by glycerol or AsIII nor aquaglyceroporin inhibitor Ag during 2 h exposure. While Si increased SbIII uptake and glucose decreased SbIII uptake by PV gametophytes, the impact disappeared during 4 h exposure. Under P-sufficient condition, P increased SbIII uptake and decreased SbV uptake during 2 h exposure, but the effect again disappeared after 4 h. After being P-starved for 2 weeks, P decreased SbIII with no effect on SbV uptake during 2 h exposure. Our results indicated that: 1) PV gametophytes could serve as an efficient model to study Sb uptake, and 2) unique SbIII uptake by PV may be related to its trait of As hyperaccumulation. PMID:26142750

  15. Uptake of antimonite and antimonate by arsenic hyperaccumulator Pteris vittata: Effects of chemical analogs and transporter inhibitor.

    PubMed

    Tisarum, Rujira; Chen, Yanshan; Dong, Xiaoling; Lessl, Jason T; Ma, Lena Q

    2015-11-01

    Antimonite (SbIII) is transported into plants via aquaglyceroporin channels but it is unknown in As-hyperaccumulator Ptreis vittata (PV). We tested the effects of SbIII analogs (arsenite-AsIII, glycerol, silicic acid-Si, and, glucose), antimonate (SbV) analog (phosphate-P), and aquaglyceroporin transporter inhibitor (silver, Ag) on the uptake of SbIII or SbV by PV gametophytes. PV gametophytes were grown in 20% Hoagland solution containing 65 μM SbIII or SbV and increasing concentrations of analogs at 65-6500 μM for 2 h or 4 h under sterile condition. After exposing to 65 μM Sb for 2 h, PV accumulated 767 mg/kg Sb in SbIII treatment and 419 mg/kg in SbV treatment. SbIII uptake by PV gametophytes was not impacted by glycerol or AsIII nor aquaglyceroporin inhibitor Ag during 2 h exposure. While Si increased SbIII uptake and glucose decreased SbIII uptake by PV gametophytes, the impact disappeared during 4 h exposure. Under P-sufficient condition, P increased SbIII uptake and decreased SbV uptake during 2 h exposure, but the effect again disappeared after 4 h. After being P-starved for 2 weeks, P decreased SbIII with no effect on SbV uptake during 2 h exposure. Our results indicated that: 1) PV gametophytes could serve as an efficient model to study Sb uptake, and 2) unique SbIII uptake by PV may be related to its trait of As hyperaccumulation.

  16. Phil Ochs: No Place in This World

    ERIC Educational Resources Information Center

    Doughty, Howard A.

    2005-01-01

    Phil Ochs was a prominent topical songwriter and singer in the 1960s. He was conventionally considered second only to Bob Dylan in terms of popularity, creativity and influence in the specific genre of contemporary folk music commonly known as "protest music." Whereas Dylan successfully reinvented himself many times in terms of his musical style…

  17. Atmospheric chemistry of CF3CF2OCH3

    NASA Astrophysics Data System (ADS)

    Østerstrøm, Freja F.; Nielsen, Ole John; Wallington, Timothy J.

    2016-06-01

    Smog chamber Fourier transform infrared techniques were used to investigate the kinetics of the reaction of CF3CF2OCH3 with Cl atoms and OH radicals: k(Cl + CF3CF2OCH3) = (1.09 ± 0.16) × 10-13 and k(OH + CF3CF2OCH3) = (1.28 ± 0.19) × 10-14 cm3 molecule-1 s-1 in 700 Torr total pressure of N2/O2 at 296 ± 2 K. The Cl-initiated oxidation of CF3CF2OCH3 gives CF3CF2OCHO in a yield indistinguishable from 100%. An estimate of k(Cl + CF3CF2OCHO) = (1.18 ± 0.34) × 10-14 cm3 molecule-1 s-1 is provided. Based on the OH reaction rate, the atmospheric lifetime of CF3CF2OCH3 is estimated to be 5.0 years. The 100-year time horizon global warming potential of CF3CF2OCH3 is estimated to be 585. The atmospheric impact of CF3CF2OCH3 is discussed.

  18. Escherichia coli type III secretion system 2 (ETT2) is widely distributed in avian pathogenic Escherichia coli isolates from Eastern China.

    PubMed

    Wang, S; Liu, X; Xu, X; Zhao, Y; Yang, D; Han, X; Tian, M; Ding, C; Peng, D; Yu, S

    2016-10-01

    Pathogens utilize type III secretion systems to deliver effector proteins, which facilitate bacterial infections. The Escherichia coli type III secretion system 2 (ETT2) which plays a crucial role in bacterial virulence, is present in the majority of E. coli strains, although ETT2 has undergone widespread mutational attrition. We investigated the distribution and characteristics of ETT2 in avian pathogenic E. coli (APEC) isolates and identified five different ETT2 isoforms, including intact ETT2, in 57·6% (141/245) of the isolates. The ETT2 locus was present in the predominant APEC serotypes O78, O2 and O1. All of the ETT2 loci in the serotype O78 isolates were degenerate, whereas an intact ETT2 locus was mostly present in O1 and O2 serotype strains, which belong to phylogenetic groups B2 and D, respectively. Interestingly, a putative second type III secretion-associated locus (eip locus) was present only in the isolates with an intact ETT2. Moreover, ETT2 was more widely distributed in APEC isolates and exhibited more isoforms compared to ETT2 in human extraintestinal pathogenic E. coli, suggesting that APEC might be a potential risk to human health. However, there was no distinct correlation between ETT2 and other virulence factors in APEC.

  19. Removal of Antimonite (Sb(III)) and Antimonate (Sb(V)) from Aqueous Solution Using Carbon Nanofibers That Are Decorated with Zirconium Oxide (ZrO2).

    PubMed

    Luo, Jinming; Luo, Xubiao; Crittenden, John; Qu, Jiuhui; Bai, Yaohui; Peng, Yue; Li, Junhua

    2015-09-15

    Zirconium oxide (ZrO2)-carbon nanofibers (ZCN) were fabricated and batch experiments were used to determine antimonite (Sb(III)) and antimonate (Sb(V)) adsorption isotherms and kinetics. ZCN have a maximum Sb(III) and Sb(V) adsorption capacity of 70.83 and 57.17 mg/g, respectively. The adsorption process between ZCN and Sb was identified to be an exothermic and follows an ion-exchange reaction. The application of ZCN was demonstrated using tap water spiked with Sb (200 μg/L). We found that the concentration of Sb was well below the maximum contaminant level for drinking water with ZCN dosages of 2 g/L. X-ray photoelectron spectroscopy (XPS) revealed that an ionic bond of Zr-O was formed with Sb(III) and Sb(V). Based on the density functional theory (DFT) calculations, Sb(III) formed Sb-O and O-Zr bonds on the surface of the tetragonal ZrO2 (t-ZrO2) (111) plane and monoclinic ZrO2 planes (m-ZrO2) (111) plane when it adsorbs. Only an O-Zr bond was formed on the surface of t-ZrO2 (111) plane and m-ZrO2 (111) plane for Sb(V) adsorption. The adsorption energy (Ead) of Sb(III) and Sb(V) onto t-ZrO2 (111) plane were 1.13 and 6.07 eV, which were higher than that of m-ZrO2 (0.76 and 3.35 eV, respectively).

  20. Crystallization-induced dynamic resolution R-epimer from 25-OCH3-PPD epimeric mixture.

    PubMed

    Zhang, Sainan; Tang, Yun; Cao, Jiaqing; Zhao, Chen; Zhao, Yuqing

    2015-11-15

    25-OCH3-PPD is a promising antitumor dammarane sapogenin isolated from the total saponin-hydrolyzed extract of Panax ginseng berry and Panax notoginseng leaves. 20(R)-25-OCH3-PPD was more potent as an anti-cancer agent than 20(S)-25-OCH3-PPD and epimeric mixture of 25-OCH3-PPD. This paper describes the rapid separation process of the R-epimer of 25-OCH3-PPD from its epimeric mixture by crystallization-induced dynamic resolution (CIDR). The optimized CIDR process was based on single factor analysis and nine well-planned orthogonal design experiments (OA9 matrix). A rapid and sensitive reverse phase high-performance liquid chromatographic (HPLC) method with evaporative light-scattering detector (ELSD) was developed and validated for the quantitation of 25-OCH3-PPD epimeric mixture and crystalline product. Separation and quantitation were achieved with a silica column using a mobile phase consisting of methanol and water (87:13, v/v) at a flow rate of 1.0mL/min. The ELSD detection was performed at 50°C and 3L/min. Under conditions involving 3mL of 95% ethanol, 8% HCl, and a hermetically sealed environment for 72h, the maximum production of 25(R)-OCH3-PPD was achieved with a chemical purity of 97% and a total yield of 87% through the CIDR process. The 25(R)-OCH3-PPD was nearly completely separated from the 220mg 25-OCH3-PPD epimeric mixture. Overall, a simple and steady small-batch purification process for the large-scale production of 25(R)-OCH3-PPD from 25-OCH3-PPD epimeric mixture was developed.

  1. Crystallization-induced dynamic resolution R-epimer from 25-OCH3-PPD epimeric mixture.

    PubMed

    Zhang, Sainan; Tang, Yun; Cao, Jiaqing; Zhao, Chen; Zhao, Yuqing

    2015-11-15

    25-OCH3-PPD is a promising antitumor dammarane sapogenin isolated from the total saponin-hydrolyzed extract of Panax ginseng berry and Panax notoginseng leaves. 20(R)-25-OCH3-PPD was more potent as an anti-cancer agent than 20(S)-25-OCH3-PPD and epimeric mixture of 25-OCH3-PPD. This paper describes the rapid separation process of the R-epimer of 25-OCH3-PPD from its epimeric mixture by crystallization-induced dynamic resolution (CIDR). The optimized CIDR process was based on single factor analysis and nine well-planned orthogonal design experiments (OA9 matrix). A rapid and sensitive reverse phase high-performance liquid chromatographic (HPLC) method with evaporative light-scattering detector (ELSD) was developed and validated for the quantitation of 25-OCH3-PPD epimeric mixture and crystalline product. Separation and quantitation were achieved with a silica column using a mobile phase consisting of methanol and water (87:13, v/v) at a flow rate of 1.0mL/min. The ELSD detection was performed at 50°C and 3L/min. Under conditions involving 3mL of 95% ethanol, 8% HCl, and a hermetically sealed environment for 72h, the maximum production of 25(R)-OCH3-PPD was achieved with a chemical purity of 97% and a total yield of 87% through the CIDR process. The 25(R)-OCH3-PPD was nearly completely separated from the 220mg 25-OCH3-PPD epimeric mixture. Overall, a simple and steady small-batch purification process for the large-scale production of 25(R)-OCH3-PPD from 25-OCH3-PPD epimeric mixture was developed. PMID:26491820

  2. Theoretical investigation on gas-phase reaction of CF3CH2OCH3 with OH radicals and fate of alkoxy radicals (CF3CH(O•)OCH3/CF3CH2OCH2O•).

    PubMed

    Mishra, Bhupesh Kumar; Lily, Makroni; Deka, Ramesh Chandra; Chandra, Asit K

    2014-05-01

    Detailed theoretical investigation has been performed on the mechanism, kinetics and thermochemistry of the gas phase reactions of CF3CH2OCH3 (HFE-263fb2) with OH radicals using ab-initio and DFT methods. Reaction profiles are modeled including the formation of pre-reactive and post-reactive complexes at entrance and exit channels, respectively. Our calculations reveal that hydrogen abstraction from the CH2 group is thermodynamically and kinetically more facile than that from the CH3 group. Using group-balanced isodesmic reactions, the standard enthalpies of formation for CF3CH2OCH3 and radicals (CF3CHOCH3 and CF3CH2OCH2) are also reported for the first time. The calculated bond dissociation energies for the CH bonds are in good agreement with experimental results. At 298K, the calculated total rate coefficient for CF3CH2OCH3+OH reactions is found to be in good agreement with the experimental results. The atmospheric fate of the alkoxy radicals, CF3CH(O)OCH3 and CF3CH2OCH2O are also investigated for the first time using the same level of theory. Out of three plausible decomposition channels, our results clearly point out that reaction with O2 is not the dominant path leading to the formation of CF3C(O)OCH3 for the decomposition of CF3CH(O)OCH3 radical in the atmosphere. This is in accord with the recent report of Osterstrom et al. [CPL 524 (2012) 32] but found to be in contradiction with experimental finding of Oyaro et al. [JPCA 109 (2005) 337].

  3. High Resolution Laser Spectroscopy of SrOCH_3

    NASA Astrophysics Data System (ADS)

    Forthomme, D.; Linton, C.; Tokaryk, D. W.; Adam, A. G.; Granger, A. D.; Downie, L. E.; Hopkins, W. S.

    2011-06-01

    The tilde{A}2E-tilde{X}2A_1 transition of SrOCH_3 was first studied at high resolution by O'Brien et al.footnote{L. C. O'Brien, C. R. Brazier and P. F. Bernath, J. Mol. Spectrosc. 130 (1988) 33-45} using a Broida oven. However lines with typically J≤20 were not observed and congestion prevented them from resolving transitions from the Ω=1/2 component of the upper state. We have studied the tilde{B}2A_1-tilde{X}2A_1 and the tilde{A}2E-tilde{X}2A_1 transitions of SrOCH_3 in a laser ablation molecular jet source, where jet cooling and low Doppler widths greatly simplified the spectra. An optical-optical double resonance technique facilitated definite assignments in a number of the transitions observed. Our analysis of the tilde{A}2E-tilde{X}2A_1 transition was straightforward, but a perturbation was observed in the tilde{B}2A_1 K'=1 F_2 levels. A satisfactory fit was achieved for the tilde{B}2A_1-tilde{X}2A_1 transition when a separate B parameter was used to fit the perturbed levels.

  4. 30. Historic American Buildings Survey SussmanOch, Photographer 1961 FRAGMENT OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    30. Historic American Buildings Survey Sussman-Och, Photographer 1961 FRAGMENT OF FIREBACK FOUND IN A HAMPTON OUTBUILDING SHOWING THE 'NORTHAMTON' MARK - Hampton, Mansion, 535 Hampton Lane, Towson, Baltimore County, MD

  5. High-temperature X-ray diffraction measurements of fluorite-related rare earth antimonates Ln{sub 3}SbO{sub 7} (Ln=Nd, Tb) and their magnetic properties

    SciTech Connect

    Hinatsu, Yukio Doi, Yoshihiro

    2014-09-15

    Ternary rare-earth antimonates Ln{sub 3}SbO{sub 7} (Ln=rare earths) were prepared, and their structures were determined by X-ray diffraction measurements. They crystallize in an orthorhombic superstructure of cubic fluorite (space group Cmcm for Ln=La, Pr; Ccmm for Ln=Sm–Dy), in which Ln{sup 3+} ions occupy two different crystallographic sites (the 8-coordinated and 7-coordinated). For Ln=Nd, two phases with the Cmcm and Ccmm space groups coexist at room temperature. When the temperature was increased, the Nd{sub 3}SbO{sub 7} compound transformed into a single phase with the space group Cmcm. Through magnetic susceptibility measurements, an antiferromagnetic transition was observed at 3.0 K (Ln=Nd) and 7.8 K (Ln=Tb). Analysis of the magnetic specific heat for Tb{sub 3}SbO{sub 7} indicates that the 8-coordinated Tb ions magnetically orders at 7.8 K, and with furthermore decreasing temperature, the 7-coordinated Tb ions shows antiferromagnetic ordering at 3.0 K. - Graphical abstract: Temperature dependence of the specific heat divided by temperature (C{sub p}/T) and the magnetic entropy (S{sub mag}) for Tb{sub 3}SbO{sub 7}. Two-step magnetic transition has been observed. - Highlights: • The phase transition of Nd{sub 3}SbO{sub 7} is from the Ccmm space group to the Cmcm one. • Nd{sub 3}SbO{sub 7} shows an antiferromagnetic transition at 3.0 K. • For Tb{sub 3}SbO{sub 7}, two-step magnetic transition has been observed at 7.8 and 3.0 K.

  6. Protein Production with a Pichia pastoris OCH1 Knockout Strain in Fed-Batch Mode.

    PubMed

    Gmeiner, Christoph; Spadiut, Oliver

    2015-01-01

    The methylotrophic yeast Pichia pastoris is a widely used host organism for recombinant protein production in biotechnology and pharmaceutical industry. However, if the target product describes a glycoprotein, an α-1,6-mannosyltransferase located in the Golgi apparatus of P. pastoris, called OCH1, triggers hypermannosylation of the recombinant protein which significantly impedes following unit operations and hampers biopharmaceutical product applications. A knockout of the och1 gene allows the production of less-glycosylated proteins-however, morphology and physiology of P. pastoris also change, complicating the upstream process. Here, we describe a controlled and efficient bioprocess based on the specific substrate uptake rate (q s) for a recombinant P. pastoris OCH1 knockout strain expressing a peroxidase as model protein. PMID:26082217

  7. Transition from two to one integument in Prunus species: expression pattern of INNER NO OUTER (INO), ABERRANT TESTA SHAPE (ATS) and ETTIN (ETT).

    PubMed

    Lora, Jorge; Hormaza, José I; Herrero, Maria

    2015-10-01

    While gymnosperm ovules have one integument, in most angiosperms two integuments surround the ovules. Unitegmic ovules have arisen independently several times during the evolution of angiosperms, but the ultimate genetic cause of the presence of a single integument remains elusive. We compared species of the genus Prunus that have different numbers of integuments: bitegmic species, such as Prunus armeniaca (apricot) and Prunus persica (peach), and unitegmic species, such as Prunus incisa, analyzing the expression pattern of genes that are involved in integument development in Arabidopsis thaliana: INNER NO OUTER (INO), ABERRANT TESTA SHAPE (ATS) and ETTIN (ETT). Bitegmic and unitegmic species showed similar INO expression patterns, indicative of the conservation of an outer integument. However, expression of ETT, which occurs in the boundary of the outer and inner integuments, was altered in unitegmic ovules, which showed lack of ETT expression. These results strongly suggest that the presence of a single integument could be attributable to the amalgamation of two integuments and support the role of ETT in the fusion of the outer and inner integuments in unitegmic ovules, a situation that could be widespread in other unitegmic species of angiosperms.

  8. Transition from two to one integument in Prunus species: expression pattern of INNER NO OUTER (INO), ABERRANT TESTA SHAPE (ATS) and ETTIN (ETT).

    PubMed

    Lora, Jorge; Hormaza, José I; Herrero, Maria

    2015-10-01

    While gymnosperm ovules have one integument, in most angiosperms two integuments surround the ovules. Unitegmic ovules have arisen independently several times during the evolution of angiosperms, but the ultimate genetic cause of the presence of a single integument remains elusive. We compared species of the genus Prunus that have different numbers of integuments: bitegmic species, such as Prunus armeniaca (apricot) and Prunus persica (peach), and unitegmic species, such as Prunus incisa, analyzing the expression pattern of genes that are involved in integument development in Arabidopsis thaliana: INNER NO OUTER (INO), ABERRANT TESTA SHAPE (ATS) and ETTIN (ETT). Bitegmic and unitegmic species showed similar INO expression patterns, indicative of the conservation of an outer integument. However, expression of ETT, which occurs in the boundary of the outer and inner integuments, was altered in unitegmic ovules, which showed lack of ETT expression. These results strongly suggest that the presence of a single integument could be attributable to the amalgamation of two integuments and support the role of ETT in the fusion of the outer and inner integuments in unitegmic ovules, a situation that could be widespread in other unitegmic species of angiosperms. PMID:25991552

  9. Analysis of the Vibrational Spectra of P_3N_3(OCH_2CF_3)_6 and P_4N_4(OCH_2CF_3)_8

    NASA Astrophysics Data System (ADS)

    King, Adrian K.; Plant, David F.; Golding, Peter; Lawson, Michael A.; Davies, Paul B.

    2011-06-01

    The cyclic phosphazene trimer P_3N_3(OCH_2CF_3)_6 and the related cyclic tetramer P_4N_4(OCH_2CF_3)_8 have been proposed as the major low-to-medium temperature pyrolysis products of the parent polyphosphazene (PN(OCH_2CF_3)_2)_n. Recently, both molecules have been synthesized, isolated and their vapour-phase vibrational spectra recorded using a high-resolution FTIR instrument. The interpretation of these spectra is achieved primarily by comparison with the results of high-quality density functional calculations, which enable the principal absorption features to be assigned and conclusions to be drawn regarding the geometries and conformations adopted by both molecules. These in turn allow interesting comparisons to be made with analogous cyclic halo-phosphazenes such as P_3N_3Cl_6 and P_4N_4Cl_8. Work to record in situ the spectra of the vapour-phase pyrolysis products of (PN(OCH_2CF_3)_2)_n and to analyse these results in terms of the tetramer and trimer spectra will also be presented. S. V. Peddada and J. H. Magill Macromolecules 16 (1983) 1258-1264. H. R. Allcock, G. S. McDonnell, G. H. Riding, and I. Manners Chem. Mater. 2 (1990) 425-432. T. R. Manley and D. A. Williams Spectrochimica Acta 23A (1966) 149-165. V. Varma, J. R. Fernandez and C. N. R. Rao J. Mol. Struct. 198 (1989) 403-412.

  10. Atmospheric degradation mechanism of CF{sub 3}OCH{sub 3}

    SciTech Connect

    Christensen, L.K.; Wallington, T.J.; Guschin, A.; Hurley, M.D.

    1999-05-27

    Recognition of the adverse effect of chlorofluorocarbon (CFC) release into the atmosphere has led to an international effort to replace CFCs with environmentally acceptable alternatives. Hydrofluoroethers (HFEs) are a class of compounds which have been developed to replace CFCs in applications such as the cleaning of electronic equipment, heat transfer agents in refrigeration systems, and carrier fluids for lubricant deposition. HFEs are volatile compounds and are released into the atmosphere when used. CF{sub 3}OCH{sub 3} has not been used commercially but is one of the simplest fluoroethers and serves as a model compound for the group of fluorinated ethers. A smog chamber/FTIR technique was used to study the Cl atom initiated oxidation of CF{sub 3}OCH{sub 3} in 700 Torr of N{sub 2}/O{sub 2} at 296 K. Using relative rate techniques it was determined that {kappa}(Cl + CF{sub 3}OCH{sub 3}) = (1.4 {+-} 0.2) {times} 10{sup {minus}13} and {kappa}(Cl + CF{sub 3}OC(O)H) = (9.8 {+-} 1.2) {times} 10{sup {minus}15} cm{sup 3} molecule{sup {minus}1} s{sup {minus}1}. At 700 Torr of N{sub 2}/O{sub 2} diluent at 296 K reaction with O{sub 2} is the only loss mechanism of the CF{sub 3}OCH{sub 2}O{sup {sm_bullet}} radical. The infrared spectra of the peroxy nitrates CF{sub 3}OCH{sub 2}O{sub 2}NO{sub 2} and CF{sub 3}OC(O)O{sub 2}NO{sub 2} were recorded and compared to the nonfluorinated analogues CH{sub 3}OCH{sub 2}O{sub 2}NO{sub 2} and CH{sub 3}OC(O)O{sub 2}NO{sub 2}. The thermal decomposition rate of CF{sub 3}OC(O)NO{sub 2} is (2.3 {+-} 0.1) {times} 10{sup {minus}4} s{sup {minus}1} in 700 Torr of N{sub 2} at 295.8 K. The reaction of CF{sub 3}OC(O)O{sub 2} radicals with HO{sub 2} radicals gives CF{sub 3}OC(O)H in a yield of (80 {+-} 11)%. The results are discussed with respect to the atmospheric degradation mechanism of CF{sub 3}OCH{sub 3} and other ethers.

  11. A model for Si, SiCH, SiO{sub 2}, SiOCH, and porous SiOCH etch rate calculation in inductively coupled fluorocarbon plasma with a pulsed bias: Importance of the fluorocarbon layer

    SciTech Connect

    Raballand, V.; Cartry, G.; Cardinaud, C.

    2007-09-15

    In a previous paper we showed that selective etching of porous SiOCH with respect to SiO{sub 2} and SiCH is clearly enhanced when using a pulsed bias in inductively coupled fluorocarbon plasma. To understand this pulsed process, a model for etch rate calculation is developed in the present paper. This model explains the etching/deposition threshold shift toward higher bias voltage in pulsed conditions. Rather good confidence is obtained with experimental SiO{sub 2}, Si, SiOCH and SiCH etch rates. Porous SiOCH etching is found to behave slightly differently compared to SiO{sub 2} or SiCH; its chemical etching is assumed to occur even during the beginning of off period. This point could explain why good selectivities between porous SiOCH and SiO{sub 2} and SiCH are obtained.

  12. Vibrational spectra, isolated CH stretching frequencies and CH bond lengths in CH 3OCH 2X compounds (XF, Cl, Br, I)

    NASA Astrophysics Data System (ADS)

    McKean, D. C.; Torto, I.; Morrisson, A. R.

    1983-05-01

    Infrared and Raman spectra are reported for CH 3OCH 2X, CHD 2OCD 2X, CD 3OCHDX (XF, Cl, Br, I) and for CH 3OCD 2Cl and CD 3OCH 2Cl, in various phases. νCHis values are obtained which enable CH bond lengths and dissociation energies to be predicted. The changes in bond lengths from Me 2O to MeOCH 2X and from MeOCH 2F to MeOCH 2Cl are in good agreement with those calculated ab initio and in radical disagreement with microwave-based values. The effect of halogen is to strengthen all the CH bonds present, especially that lying parallel to the CX one. All major features in the spectra are explained if only the gauche skeletal conformer exists in the phases studied. However, two transient bands in solid films of CH 3OCH 2F may indicate the presence of a metastable trans conformer phase. Secure assignments for CH 3OCH 2Cl are based on the CH 3OCD 2Cl and CD 3OCH 2Cl spectra and extended by analogy to most of the vibrations of the F, Br and I compounds.

  13. Distributed Denial of Service Attack Source Detection Using Efficient Traceback Technique (ETT) in Cloud-Assisted Healthcare Environment.

    PubMed

    Latif, Rabia; Abbas, Haider; Latif, Seemab; Masood, Ashraf

    2016-07-01

    Security and privacy are the first and foremost concerns that should be given special attention when dealing with Wireless Body Area Networks (WBANs). As WBAN sensors operate in an unattended environment and carry critical patient health information, Distributed Denial of Service (DDoS) attack is one of the major attacks in WBAN environment that not only exhausts the available resources but also influence the reliability of information being transmitted. This research work is an extension of our previous work in which a machine learning based attack detection algorithm is proposed to detect DDoS attack in WBAN environment. However, in order to avoid complexity, no consideration was given to the traceback mechanism. During traceback, the challenge lies in reconstructing the attack path leading to identify the attack source. Among existing traceback techniques, Probabilistic Packet Marking (PPM) approach is the most commonly used technique in conventional IP- based networks. However, since marking probability assignment has significant effect on both the convergence time and performance of a scheme, it is not directly applicable in WBAN environment due to high convergence time and overhead on intermediate nodes. Therefore, in this paper we have proposed a new scheme called Efficient Traceback Technique (ETT) based on Dynamic Probability Packet Marking (DPPM) approach and uses MAC header in place of IP header. Instead of using fixed marking probability, the proposed scheme uses variable marking probability based on the number of hops travelled by a packet to reach the target node. Finally, path reconstruction algorithms are proposed to traceback an attacker. Evaluation and simulation results indicate that the proposed solution outperforms fixed PPM in terms of convergence time and computational overhead on nodes. PMID:27189623

  14. A General Method for Imine Formation Using B(OCH2CF3)3.

    PubMed

    Reeves, Jonathan T; Visco, Michael D; Marsini, Maurice A; Grinberg, Nelu; Busacca, Carl A; Mattson, Anita E; Senanayake, Chris H

    2015-05-15

    Tris(2,2,2-trifluoroethyl)borate [B(OCH2CF3)3] was found to be a mild and general reagent for the formation of a variety of imines by condensation of amides or amines with carbonyl compounds. N-Sulfinyl, N-toluenesulfonyl, N-(dimethylamino)sulfamoyl, N-diphenylphosphinoyl, N-(α-methylbenzyl), and N-(4-methoxyphenyl) aldimines are all accessible using this reagent at room temperature. The reactions are operationally simple, and the products are obtained without special workup or isolation procedures. PMID:25906082

  15. Mechanism of plasma-induced damage to low-k SiOCH films during plasma ashing of organic resists

    NASA Astrophysics Data System (ADS)

    Takeda, Keigo; Miyawaki, Yudai; Takashima, Seigo; Fukasawa, Masanaga; Oshima, Keiji; Nagahata, Kazunori; Tatsumi, Tetsuya; Hori, Masaru

    2011-02-01

    Plasma-induced damage to porous SiOCH (p-SiOCH) films during organic resist film ashing using dual-frequency capacitively coupled O2 plasmas was investigated using the pallet for plasma evaluation method developed by our group. The damage was characterized by ellipsometry and Fourier-transform infrared spectroscopy. Individual and synergetic damage associated with vacuum ultraviolet (VUV) and UV radiation, radicals, and ions in the O2 plasma were clarified. It was found that the damage was caused not only by radicals but also by synergetic reactions of radicals with VUV and UV radiation emitted by the plasmas. It is noteworthy that the damage induced by plasma exposure without ion bombardment was larger than the damage with ion bombardment. These results differed from those obtained using an H2/N2 plasma for resist ashing. Finally, the mechanism of damage to p-SiOCH caused by O2 and H2/N2 plasma ashing of organic resist films is discussed. These results are very important in understanding the mechanism of plasma-induced damage to p-SiOCH films.

  16. Mechanism of plasma-induced damage to low-k SiOCH films during plasma ashing of organic resists

    SciTech Connect

    Takeda, Keigo; Miyawaki, Yudai; Takashima, Seigo; Fukasawa, Masanaga; Oshima, Keiji; Nagahata, Kazunori; Tatsumi, Tetsuya; Hori, Masaru

    2011-02-01

    Plasma-induced damage to porous SiOCH (p-SiOCH) films during organic resist film ashing using dual-frequency capacitively coupled O{sub 2} plasmas was investigated using the pallet for plasma evaluation method developed by our group. The damage was characterized by ellipsometry and Fourier-transform infrared spectroscopy. Individual and synergetic damage associated with vacuum ultraviolet (VUV) and UV radiation, radicals, and ions in the O{sub 2} plasma were clarified. It was found that the damage was caused not only by radicals but also by synergetic reactions of radicals with VUV and UV radiation emitted by the plasmas. It is noteworthy that the damage induced by plasma exposure without ion bombardment was larger than the damage with ion bombardment. These results differed from those obtained using an H{sub 2}/N{sub 2} plasma for resist ashing. Finally, the mechanism of damage to p-SiOCH caused by O{sub 2} and H{sub 2}/N{sub 2} plasma ashing of organic resist films is discussed. These results are very important in understanding the mechanism of plasma-induced damage to p-SiOCH films.

  17. Analysis of the Pressure and Temperature Dependence of the Complex-Forming Bimolecular Reaction CH3OCH3 + Fe(.).

    PubMed

    Ard, Shaun G; Johnson, Ryan S; Martinez, Oscar; Shuman, Nicholas S; Guo, Hua; Troe, Jürgen; Viggiano, Albert

    2016-07-14

    The kinetics of the reaction CH3OCH3 + Fe(+) has been studied between 250 and 600 K in the buffer gas He at pressures between 0.4 and 1.6 Torr. Total rate constants and branching ratios for the formation of Fe(+)O(CH3)2 adducts and of Fe(+)OCH2 + CH4 products were determined. Quantum-chemical calculations provided the parameters required for an analysis in terms of statistical unimolecular rate theory. The analysis employed a recently developed simplified representation of the rates of complex-forming bimolecular reactions, separating association and chemical activation contributions. Satisfactory agreement between experimental results and kinetic modeling was obtained that allows for an extrapolation of the data over wide ranges of conditions. Possible reaction pathways with or without spin-inversion are discussed in relation to the kinetic modeling results.

  18. Analysis of the Pressure and Temperature Dependence of the Complex-Forming Bimolecular Reaction CH3OCH3 + Fe(.).

    PubMed

    Ard, Shaun G; Johnson, Ryan S; Martinez, Oscar; Shuman, Nicholas S; Guo, Hua; Troe, Jürgen; Viggiano, Albert

    2016-07-14

    The kinetics of the reaction CH3OCH3 + Fe(+) has been studied between 250 and 600 K in the buffer gas He at pressures between 0.4 and 1.6 Torr. Total rate constants and branching ratios for the formation of Fe(+)O(CH3)2 adducts and of Fe(+)OCH2 + CH4 products were determined. Quantum-chemical calculations provided the parameters required for an analysis in terms of statistical unimolecular rate theory. The analysis employed a recently developed simplified representation of the rates of complex-forming bimolecular reactions, separating association and chemical activation contributions. Satisfactory agreement between experimental results and kinetic modeling was obtained that allows for an extrapolation of the data over wide ranges of conditions. Possible reaction pathways with or without spin-inversion are discussed in relation to the kinetic modeling results. PMID:27228310

  19. Atmospheric chemistry of CF{sub 3}C(O)OCH{sub 2}CF{sub 3}: UV spectra and kinetic data for CF{sub 3}C(O)OCH({sm_bullet})CF{sub 3} and CF{sub 3}C(O)OCH(OO{sm_bullet})CF{sub 3} radicals, and atmospheric fate of CF{sub 3}C(O)OCH(O{sm_bullet})CF{sub 3} radicals

    SciTech Connect

    Stein, T.N.N.; Christensen, L.K.; Platz, J.; Sehested, J.; Nielsen, O.J.; Wallington, T.J.

    1999-07-22

    Recognition of the adverse effect of chlorofluorocarbon (CFC) release into the atmosphere has led to an international effort to replace CFCs with environmentally acceptable alternatives. Hydrofluoroethers (HFEs) are fluids designed to replace CFCs in applications such as the cleaning of electronic equipment, heat transfer agents in refrigeration systems, and carrier fluids for lubricant deposition. HFEs are volatile compounds and will be released into the atmosphere during its use. In the atmosphere, photochemical oxidation of HFEs will lead to the formation of fluorinated esters and fluorinated formates. The atmospheric fate of these products is unknown at the present. To improve their understanding of the atmospheric chemistry of esters the authors have studied the atmospheric chemistry of 2,2,2-trifluoroethyltrifluoroacetate CF{sub 3}C(O)OCH{sub 2}CF{sub 3} (bp = 55.0 C). This compound provides insight into the behavior of alkyl, alkyl peroxy, and alkoxy radicals formed {alpha} to the ester functionality. The atmospheric fate of CF{sub 3}C(O)OCH(O{sup {sm_bullet}})CF{sub 3} radicals was investigated in a FTIR smog chamber. Three loss processes for the CF{sub 3}C(O)OCH(O{sup {sm_bullet}})CF{sub 3} radicals were identified at 296 K and 700 Torr total pressure, reaction with O{sub 2} to form CF{sub 3}C(O)OC(O)CF{sub 3}, {alpha}-rearrangement to form CF{sub 3}C(O){sm_bullet} radicals and CF{sub 3}C(O)OH, and decomposition via a mechanism which is unclear. In 760 Torr of air at 296 K, 65% of the CF{sub 3}C(O)OCH(O{sm_bullet})CF{sub 3} radicals react with oxygen, 18% undergo {alpha}-rearrangement, while the fate of the remaining 17% is unclear.

  20. Hydrogen and methanol exchange processes for (TMP)Rh-OCH3(CH3OH) in binary solutions of methanol and benzene.

    PubMed

    Sarkar, Sounak; Li, Shan; Wayland, Bradford B

    2011-04-18

    Tetramesityl porphinato rhodium(III) methoxide ((TMP)Rh-OCH(3)) binds with methanol in benzene to form a 1:1 methanol complex ((TMP)Rh-OCH(3)(CH(3)OH)) (1). Dynamic processes are observed to occur for the rhodium(III) methoxide methanol complex (1) that involve both hydrogen and methanol exchange. Hydrogen exchange between coordinated methanol and methoxide through methanol in solution results in an interchange of the environments for the non-equivalent porphyrin faces that contain methoxide and methanol ligands. Interchange of the environments of the coordinated methanol and methoxide sites in 1 produces interchange of the inequivalent mesityl o-CH(3) groups, but methanol ligand exchange occurs on one face of the porphyrin and the mesityl o-CH(3) groups remain inequivalent. Rate constants for dynamic processes are evaluated by full line shape analysis for the (1)H NMR of the mesityl o-CH(3) and high field methyl resonances of coordinated methanol and methoxide groups in 1. The rate constant for interchange of the inequivalent porphyrin faces is associated with hydrogen exchange between 1 and methanol in solution and is observed to increase regularly with the increase in the mole fraction of methanol. The rate constant for methanol ligand exchange between 1 and the solution varies with the solution composition and fluctuates in a manner that parallels the change in the activation energy for methanol diffusion which is a consequence of solution non-ideality from hydrogen bonded clusters.

  1. Development of a fed-batch process for a recombinant Pichia pastoris Δoch1 strain expressing a plant peroxidase.

    PubMed

    Gmeiner, Christoph; Saadati, Amirhossein; Maresch, Daniel; Krasteva, Stanimira; Frank, Manuela; Altmann, Friedrich; Herwig, Christoph; Spadiut, Oliver

    2015-01-01

    Pichia pastoris is a prominent host for recombinant protein production, amongst other things due to its capability of glycosylation. However, N-linked glycans on recombinant proteins get hypermannosylated, causing problems in subsequent unit operations and medical applications. Hypermannosylation is triggered by an α-1,6-mannosyltransferase called OCH1. In a recent study, we knocked out OCH1 in a recombinant P. pastoris CBS7435 Mut(S) strain (Δoch1) expressing the biopharmaceutically relevant enzyme horseradish peroxidase. We characterized the strain in the controlled environment of a bioreactor in dynamic batch cultivations and identified the strain to be physiologically impaired. We faced cell cluster formation, cell lysis and uncontrollable foam formation.In the present study, we investigated the effects of the 3 process parameters temperature, pH and dissolved oxygen concentration on 1) cell physiology, 2) cell morphology, 3) cell lysis, 4) productivity and 5) product purity of the recombinant Δoch1 strain in a multivariate manner. Cultivation at 30°C resulted in low specific methanol uptake during adaptation and the risk of methanol accumulation during cultivation. Cell cluster formation was a function of the C-source rather than process parameters and went along with cell lysis. In terms of productivity and product purity a temperature of 20°C was highly beneficial. In summary, we determined cultivation conditions for a recombinant P. pastoris Δoch1 strain allowing high productivity and product purity. PMID:25567661

  2. High pressure Raman spectroscopy of H2O-CH3OH mixtures.

    PubMed

    Hsieh, Wen-Pin; Chien, Yu-Hsiang

    2015-02-23

    Complex intra-molecular interactions and the hydrogen-bonding network in H2O-volatile mixtures play critical roles in many dynamics processes in physical chemistry, biology, and Earth and planetary sciences. We used high pressure Raman spectroscopy to study the pressure evolution of vibrational frequencies and bonding behavior in H2O-CH3OH mixtures. We found that the presence of low CH3OH content in H2O increases the transition pressure where water crystallizes to ice VI, but does not significantly change the pressure where ice VI transforms to ice VII. Furthermore, the stiffening rates of C-H stretching frequencies dω/dP in CH3OH significantly decrease upon the crystallization of water, and the softening rates of the O-H stretching frequencies of ice VII are suppressed over a narrow pressure range, after which the frequencies of these modes shift with pressure in ways similar to pure CH3OH and ice VII, respectively. Such complex pressure evolution of Raman frequencies along with pronounced variations in Raman intensities of CH3OH within the sample, and the hysteresis of the water-ice VI phase transition suggest pressure-induced segregation of low content CH3OH from ice VII. These findings indicate the significant influence of volatiles on the crystallization of sub-surface ocean and thermal evolution within large icy planets and satellites.

  3. Astronomical Orientations Of Dragon Houses (Laka Palli, Kapsala, Oche) And Armena Gate (Euboea, Greece)

    NASA Astrophysics Data System (ADS)

    Liritzis, I.; Artelaris, G.

    The preliminary investigation of the astronomical orientation of monuments at Styra, southern Euboea, includes the triple so called 'dragon house' complex at Laka Palli, one dragon house at Kapsala and one on the summit of Mount Oche, and a monumental gate in the megalithic fortification wall at Armena. Recent luminescence testing dates these remains to approximately the Classical period with apparent re-use in Roman and later times. Thus far no definite astronomical orientation has been determined in the layout of the structures and no celestial stone markers or similar features have been found associated with the dragon houses, however, the relationship of significant stars, constellations and solar stands was well known in antiquity, and the limited results presented here suggests the possibility for further investigation. This study, which considered possible orientations related to sun rise and sun set for the summer and winter solstice, as well as, alignments towards equinoxes and major bright stars and constellations, did observe a general preference for a southern orientation at most of the sites and a possible feature for time observations in the dragon house complex at Laka Palli.

  4. Towards understanding intrinsic degradation and breakdown mechanisms in SiOCH low-k dielectrics

    SciTech Connect

    Wu, C. De Wolf, I.; Li, Y.; Ciofi, I.; Kauerauf, Th.; Bömmels, J.; Tőkei, Zs.; Croes, K.

    2015-02-14

    The degradation and breakdown mechanisms of a SiOCH low-k material with k = 2.3 (25% porosity) and thicknesses ranging from 90 nm to 20 nm were investigated. By combining the time dependent dielectric breakdown data at positive/negative bias stress with the thickness scaling results, dielectric failure is proven to be intrinsic and not influenced by copper drift or metal barrier deposition induced dielectric damage. It is shown that stress induced leakage current (SILC) can be used as a measure of dielectric degradation. Therefore, low field lifetimes can be safely estimated using SILC extrapolation. Based on our results, both the impact damage model and the power law model have a good accuracy for low field lifetime prediction. Recovery and anneal experiments are used to study the physical nature causing the observed negative flatband voltage shifts in our metal-insulator-semiconductor planar capacitor structures, where hydrogen induced unstable fast and slow donor type interface states are hypothesized to be the root cause of the observed shifts. We suggest that atomic hydrogen is released from the dielectric during electron injection and migrates to the interfacial region. Our model is further supported by an observed irreversible SILC change during the recovery and anneal studies. The degradation mechanism proposed in this work, supported by the low field lifetime data, provides a feasible explanation for intrinsic low-k dielectric failure.

  5. Role of the host tissue in the anti-invasive activity of the alkyllysophospholipid, ET-18-OCH3, in vitro.

    PubMed

    Schallier, D C; Bruyneel, E A; Storme, G A; Mareel, M M

    1991-01-01

    The alkyllysophospholipid, racemic-l-O-octadecyl-2-O-methylglycero-3- phosphocholine (ET-18-OCH3) was previously shown to inhibit invasion of malignant cells into precultured heart fragments (PHF) in vitro. In particular, pretreatment of PHF with 10 micrograms ET-18-OCH3 for 48 h was sufficient to induce in the host tissue resistance towards invasion by mouse MO4 cells. Resistance was obvious when MO4 cells were confronted either immediately (the pretreatment experiment) or after withdrawal of the drug 7 days prior to confrontation (the reversibility experiment). In the present study, the survival of PHF cells in the pretreatment and reversibility experiments was similar to that of untreated PHF cells as determined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) test and by the PHF explantation test. The effective anti-invasive concentration was 6 micrograms/ml in the pretreatment experiment while 3 micrograms/ml was sufficient to inhibit invasion in the reversibility experiment. Induction of resistance towards invasion in pretreated PHF was shown to occur not only with MO4 cells but also with mouse LLC-H61 Lewis lung carcinoma and mouse BW-O-Li1 T-lymphoma cells. The increase in molecular weight of N-linked cell surface glycosylpeptides (N-GP) of PHF was apparent in the pretreatment experiment and was enhanced in the reversibility experiment. This effect was completely abolished in cells obtained from pretreated PHF which were converted into a cell suspension and further cultured as a monolayer on tissue culture plastic without drug for 7 days. The results reported here provide additional evidence for the causal involvement of N-GP of the PHF host tissue in the anti-invasive activity of ET-18-OCH3 in vitro.

  6. Investigation of the O+allyl addition/elimination reaction pathways from the OCH(2)CHCH(2) radical intermediate.

    PubMed

    Fitzpatrick, Benjamin L; Lau, Kai-Chung; Butler, Laurie J; Lee, Shih-Huang; Lin, Jim Jr-Min

    2008-08-28

    These experiments study the preparation of and product channels resulting from OCH(2)CHCH(2), a key radical intermediate in the O+allyl bimolecular reaction. The data include velocity map imaging and molecular beam scattering results to probe the photolytic generation of the radical intermediate and the subsequent pathways by which the radicals access the energetically allowed product channels of the bimolecular reaction. The photodissociation of epichlorohydrin at 193.3 nm produces chlorine atoms and c-OCH(2)CHCH(2) radicals; these undergo a facile ring opening to the OCH(2)CHCH(2) radical intermediate. State-selective resonance-enhanced multiphoton ionization (REMPI) detection resolves the velocity distributions of ground and spin-orbit excited state chlorine independently, allowing for a more accurate determination of the internal energy distribution of the nascent radicals. We obtain good agreement detecting the velocity distributions of the Cl atoms with REMPI, vacuum ultraviolet (VUV) photoionization at 13.8 eV, and electron bombardment ionization; all show a bimodal distribution of recoil kinetic energies. The dominant high recoil kinetic energy feature peaks near 33 kcalmol. To elucidate the product channels resulting from the OCH(2)CHCH(2) radical intermediate, the crossed laser-molecular beam experiment uses VUV photoionization and detects the velocity distribution of the possible products. The data identify the three dominant product channels as C(3)H(4)O (acrolein)+H, C(2)H(4)+HCO (formyl radical), and H(2)CO (formaldehyde)+C(2)H(3). A small signal from C(2)H(2)O (ketene) product is also detected. The measured velocity distributions and relative signal intensities at me=27, 28, and 29 at two photoionization energies show that the most exothermic product channel, C(2)H(5)+CO, does not contribute significantly to the product branching. The higher internal energy onset of the acrolein+H product channel is consistent with the relative barriers en route to

  7. Incorporation of a Rovibrational Analysis of OC-H_2O Into 6-D Morphed Potentials of the Complex

    NASA Astrophysics Data System (ADS)

    Rivera-Rivera, Luis A.; Springer, Sean D.; McElmurry, Blake A.; Leonov, Igor I.; Lucchese, Robert R.; Bevan, John W.; Coudert, L. H.

    2016-06-01

    Rovibrational transitions associated with tunneling states in the water bending vibration in OC-H_2O and other available spectroscopic data are included in generation of 6-D morphed potentials of the complex. Six-dimension ab initio interaction potentials are initially calculated for the complex to provided the initial functions for the potential morphing. The available spectroscopic data is then used to fit and generate 6-D morphed potentials. Previous prediction of the D_0 of the complex will be incorporated in the analysis. Finally, intermolecular frequencies of the complex will be predicted using the 6-D morphed potentials involving the CO stretching and the H_2O bending vibrations.

  8. Atmospheric Degradation of CH2═C(CH3)C(O)OCH3 Initiated by OH Radicals: Mechanistic Study and Quantification of CH3C(O)C(O)OCH3 in NOx Free Air.

    PubMed

    Gibilisco, Rodrigo G; Uranga, Jorge G; Santiago, Ana N; Teruel, Mariano A

    2015-08-20

    The product distribution of the gas-phase reaction of OH radicals with methyl methacrylate (CH2═C(CH3)C(O)OCH3, MMA) in the absence of NOx was studied at 298 K and atmospheric pressure of air. The experiments were performed in a Teflon chamber using solid-phase microextraction (SPME) with GC-MS and GC-FID for product identification and quantification, respectively. In the absence of NOx, methyl pyruvate (CH3C(O)C(O)OCH3) was identified with a yield of 76 ± 13% in accordance with the decomposition of the 1,2-hydroxyalkoxy radicals formed. In addition, a detailed quantum chemical study of the degradation of MMA was performed by density functional theory (DFT) methods using the MPWB1K functional. This calculation suggests that formation of methyl pyruvate, from C1-C2 scission of 1,2-hydroxyalkoxy radical, is kinetically and thermodynamically the most favorable reaction path taking into account the electronic properties of reaction intermediates and transition states. The difference observed on the degradation mechanism of MMA in the presence and absence of NOx was explained in terms of the associated thermochemistry. Furthermore, this study propose that reaction between peroxy radical (RO2(•)) and hydroxyl radical (OH) became relevant at NOx-free environments. This statement is in agreement with recent studies concerning small peroxy radicals such as CH3OO(•).

  9. Atmospheric Degradation of CH2═C(CH3)C(O)OCH3 Initiated by OH Radicals: Mechanistic Study and Quantification of CH3C(O)C(O)OCH3 in NOx Free Air.

    PubMed

    Gibilisco, Rodrigo G; Uranga, Jorge G; Santiago, Ana N; Teruel, Mariano A

    2015-08-20

    The product distribution of the gas-phase reaction of OH radicals with methyl methacrylate (CH2═C(CH3)C(O)OCH3, MMA) in the absence of NOx was studied at 298 K and atmospheric pressure of air. The experiments were performed in a Teflon chamber using solid-phase microextraction (SPME) with GC-MS and GC-FID for product identification and quantification, respectively. In the absence of NOx, methyl pyruvate (CH3C(O)C(O)OCH3) was identified with a yield of 76 ± 13% in accordance with the decomposition of the 1,2-hydroxyalkoxy radicals formed. In addition, a detailed quantum chemical study of the degradation of MMA was performed by density functional theory (DFT) methods using the MPWB1K functional. This calculation suggests that formation of methyl pyruvate, from C1-C2 scission of 1,2-hydroxyalkoxy radical, is kinetically and thermodynamically the most favorable reaction path taking into account the electronic properties of reaction intermediates and transition states. The difference observed on the degradation mechanism of MMA in the presence and absence of NOx was explained in terms of the associated thermochemistry. Furthermore, this study propose that reaction between peroxy radical (RO2(•)) and hydroxyl radical (OH) became relevant at NOx-free environments. This statement is in agreement with recent studies concerning small peroxy radicals such as CH3OO(•). PMID:26213280

  10. Theoretical investigation of the gas-phase reactions of CF2ClC(O)OCH3 with the hydroxyl radical and the chlorine atom at 298 K.

    PubMed

    Mishra, Bhupesh Kumar; Chakrabartty, Arup Kumar; Deka, Ramesh Chandra

    2013-08-01

    A Theoretical study on the mechanism of the reactions of CF2ClC(O)OCH3 with the OH radical and Cl atom is presented. Geometry optimization and frequency calculations have been performed at the MPWB1K/6-31+G(d,p) level of theory and energetic information is further refined by calculating the energy of the species using G2(MP2) theory. Transition states are searched on the potential energy surface involved during the reaction channels and each of the transition states are characterized by presence of only one imaginary frequency. The existence of transition states on the corresponding potential energy surface is ascertained by performing intrinsic reaction coordinate (IRC) calculation. Theoretically calculated rate constants at 298 K and atmospheric pressure using the canonical transition state theory (CTST) are found to be in good agreement with the experimentally measured ones. Using group-balanced isodesmic reactions as working chemical reactions, the standard enthalpies of formation for CF2ClC(O)OCH3, CF2ClC(O)OCH2 and CF3C(O)OCH3 are also reported for the first time.

  11. Long persistent near infrared luminescence nanoprobes LiGa5O8:Cr3+-PEG-OCH3 for in vivo imaging

    NASA Astrophysics Data System (ADS)

    Fu, Xiaoyan; Liu, Chunlin; Shi, Junpeng; Man, Huizi; Xu, Jia; Zhang, Hongwu

    2014-09-01

    The Cr3+-doped LiGa5O8 nanoparticles (LGNPs) with long-persistent near-infrared phosphorescence were obtained through a sol-gel approach followed by heat treatment at 800 °C in air. The obtained results reveal that the nanoparticles with an average diameter of 100 nm are well defined and have pure structure of LiGa5O8. After illumination for 3 min using a 254 nm UV lamp, the LGNPs exhibit strong near-infrared peak at ca. 720 nm belonging to tissue transparency window which can last for more than 1 h. Via surface modified with PEG-5000-OCH3, the LGNPs-PEG-OCH3 exhibit excellent biocompatibility and low toxicity. Under in vitro pre-excitation using a 254 nm UV lamp for 3 min, the in vivo distribution of the LGNPs-PEG-OCH3 in the abdomen can be detected in real time for more than 1 h. All the results indicate that the LGNPs-PEG-OCH3 can be used as potential nanoprobes to realize in vivo, real time and long time imaging with high sensitivity.

  12. Effects of different media supplements on the production of an active recombinant plant peroxidase in a Pichia pastoris Δoch1 strain.

    PubMed

    Gmeiner, Christoph; Spadiut, Oliver

    2015-01-01

    Recombinant protein production in microorganisms is one of the most studied areas of research in biotechnology today. In this respect the yeast Pichia pastoris is an important microbial production host due to its capability of secreting the target protein and performing posttranslational modifications. In a recent study, we described the development of a robust bioprocess for a glyco-engineered recombinant P. pastoris strain where the native α-1,6-mannosyltransfrease OCH1 was knocked out (Δoch1 strain). This strain produced the glycosylated enzyme horseradish peroxidase (HRP) with more homogeneous and shorter surface glycans than the respective benchmark strain. However, the recombinant Δoch1 strain was physiologically impaired and thus hard to cultivate. We faced cell cluster formation, cell lysis and consequent intensive foam formation. Thus, we investigated the effects of the 3 process parameters temperature, pH and dissolved oxygen concentration on (1) cell physiology, (2) cell morphology, (3) cell lysis, (4) productivity and (5) product purity in a multivariate manner. However, not only process parameters might influence these characteristics, but also media supplements might have an impact. Here, we describe the effects of different heme-precursors as well as of a protease-inhibitor cocktail on the production of active HRP in therecombinant P. pastoris Δoch1strain.

  13. Induction of apoptosis in human mitogen-activated peripheral blood T-lymphocytes by the ether phospholipid ET-18-OCH3: Involvement of the Fas receptor/ligand system

    PubMed Central

    Cabaner, Christelle; Gajate, Consuelo; Macho, Antonio; Muñoz, Eduardo; Modolell, Manuel; Mollinedo, Faustino

    1999-01-01

    Activated T-cells constitute a target for treatment of autoimmune diseases. We have found that the antitumour ether phospholipid 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3; edelfosine) induced dose- and time-dependent apoptosis in human mitogen-activated peripheral blood T-lymphocytes, but not in resting T-cells. T-lymphocytes were stimulated with phytohemagglutinin and interleukin-2 or with concanavalin A. Apoptosis was assessed by DNA fragmentation through cell cycle and TUNEL analyses, as well as through visualization of internucleosomal DNA fragmentation in agarose gels.The ET-18-OCH3-mediated apoptotic response in activated T-lymphocytes was less intense than in human leukaemic T cell lines, such as Jurkat cells and Peer cells; namely about 25% apoptosis in activated T-cells versus about 46–61% apoptosis in T leukaemic cells after 24 h treatment with 10 μM ET-18-OCH3.The ET-18-OCH3 thioether analogue BM 41.440 (ilmofosine) showed a similar apoptotic capacity to that found with ET-18-OCH3 in activated T-cells, whereas the phospholipid analogue hexadecylphosphocholine (miltefosine) failed to promote this response.The uptake of [3H]-ET-18-OCH3 was much larger in activated T-cells than in resting lymphocytes.Using a cytofluorimetric approach we have found that ET-18-OCH3 induced disruption of the mitochondrial transmembrane potential and production of reactive oxygen species in activated T-cells, but not in resting lymphocytes.ET-18-OCH3 induced an increase in Fas (APO-1/CD95) ligand mRNA expression in activated T-cells, and incubation with a blocking anti-Fas (APO-1/CD95) antibody partially inhibited the ET-18-OCH3-induced apoptosis of activated T-lymphocytes.These results demonstrate that mitogen-activated T-cells, unlike resting lymphocytes, are able to take up significant amounts of ET-18-OCH3, and are susceptible to undergo apoptosis by the ether lipid via, in part, the Fas (APO-1/CD95) receptor/ligand system. This ET-18-OCH3

  14. Characterization of Cu(II) and Cd(II) resistance mechanisms in Sphingobium sp. PHE-SPH and Ochrobactrum sp. PHE-OCH and their potential application in the bioremediation of heavy metal-phenanthrene co-contaminated sites.

    PubMed

    Chen, Chen; Lei, Wenrui; Lu, Min; Zhang, Jianan; Zhang, Zhou; Luo, Chunling; Chen, Yahua; Hong, Qing; Shen, Zhenguo

    2016-04-01

    Soil that is co-contaminated with heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) is difficult to bioremediate due to the ability of toxic metals to inhibit PAH degradation by bacteria. We demonstrated the resistance mechanisms to Cu(II) and Cd(II) of two newly isolated strains of Sphingobium sp. PHE-SPH and Ochrobactrum sp. PHE-OCH and further tested their potential application in the bioremediation of HM-phenanthrene (PhA) co-contaminated sites. The PHE-SPH and PHE-OCH strains tolerated 4.63 and 4.34 mM Cu(II) and also showed tolerance to 0.48 and 1.52 mM Cd(II), respectively. Diverse resistance patterns were detected between the two strains. In PHE-OCH cells, the maximum accumulation of Cu(II) occurred in the cell wall, while the maximum accumulation was in the cytoplasm of PHE-SPH cells. This resulted in a sudden suppression of growth in PHE-OCH and a gradual inhibition in PHE-SPH as the concentration of Cu(II) increased. Organic acid production was markedly higher in PHE-OCH than in PHE-SPH, which may also have a role in the resistance mechanisms, and contributes to the higher Cd(II) tolerance of PHE-OCH. The factors involved in the absorption of Cu(II) or Cd(II) in PHE-SPH and PHE-OCH were identified as proteins and carbohydrates by Fourier transform infrared (FT-IR) spectroscopy. Furthermore, both strains showed the ability to efficiently degrade PhA and maintained this high degradation efficiency under HM stress. The high tolerance to HMs and the PhA degradation capacity make Sphingobium sp. PHE-SPH and Ochrobactrum sp. PHE-OCH excellent candidate organisms for the bioremediation of HM-PhA co-contaminated sites.

  15. Damage by radicals and photons during plasma cleaning of porous low-k SiOCH. II. Water uptake and change in dielectric constant

    SciTech Connect

    Shoeb, Juline; Kushner, Mark J.

    2012-07-15

    Porous dielectric materials provide lower capacitances that reduce RC time delays in integrated circuits. Typical low-k materials include porous SiOCH-silicon dioxide with carbon groups, principally CH{sub 3}, lining the pores. With a high porosity, internally connected pores provide pathways for reactive species to enter into the material. Fluorocarbon plasmas are often used to etch SiOCH, a process that leaves a fluorocarbon polymer on the surface that must later be removed. During cleaning using Ar/O{sub 2} or He/H{sub 2} plasmas, reactions of radicals that diffuse into the SiOCH and photons that penetrate into the SiOCH can remove -CH{sub 3} groups. Due to its higher reactivity, cleaning with Ar/O{sub 2} plasmas removes more -CH{sub 3} groups than He/H{sub 2} plasmas, and so produce more free radical sites, such as -SiO{sub 2} Bullet (a -SiO{sub 2}-CH{sub 3} site with the -CH{sub 3} group removed).Upon exposure to humid air, these free radical sites can chemisorb H{sub 2}O to form hydrophilic Si-OH which can further physisorb H{sub 2}O through hydrogen bonding to form Si-OH(H{sub 2}O). With the high dielectric constant of water, even a small percentage of water uptake can significantly increase the effective dielectric constant of SiOCH. In this paper, we report on results from a computational investigation of the cleaning of SiOCH using Ar/O{sub 2} or He/H{sub 2} plasmas and subsequent exposure to humid air. The authors found that plasma cleaning with He/H{sub 2} mixtures produce less demethylation than cleaning with Ar/O{sub 2} plasmas, as so results in less water uptake, and a smaller increase in dielectric constant. The water that produces the increase in dielectric constant is roughly half chemisorbed and half physisorbed, the latter of which can be removed with mild heating. Sealing the pores with NH{sub 3} plasma treatment reduces water uptake and helps prevent the increase in dielectric constant.

  16. Improving mechanical robustness of ultralow-k SiOCH plasma enhanced chemical vapor deposition glasses by controlled porogen decomposition prior to UV-hardening

    NASA Astrophysics Data System (ADS)

    Urbanowicz, A. M.; Vanstreels, K.; Verdonck, P.; Shamiryan, D.; De Gendt, S.; Baklanov, M. R.

    2010-05-01

    We report a new curing procedure of a plasma enhanced chemical vapor deposited SiCOH glasses for interlayer dielectric applications in microelectronic. It is demonstrated that SiOCH glasses with improved mechanical properties and ultralow dielectric constant can be obtained by controlled decomposition of the porogen molecules used to create nanoscale pores, prior to the UV-hardening step. The Young's modulus (YM) of conventional SiOCH-based glasses with 32% open porosity hardened with porogen is 4.6 GPa, this value is shown to increase up to 5.2 GPa with even 46% open porosity, when the glasses are hardened after porogen removal. This increase in porosity is accompanied by significant reduction in the dielectric constant from 2.3 to 1.8. The increased YM is related to an enhanced molecular-bridging mechanism when film is hardened without porogen that was explained on the base of percolation of rigidity theory and random network concepts.

  17. Conformational and spectroscopic study of xanthogen ethyl formates, ROC(S)SC(O)OCH2CH3. Isolation of CH3CH2OC(O)SH

    NASA Astrophysics Data System (ADS)

    Juncal, Luciana C.; Cozzarín, Melina V.; Romano, Rosana M.

    2015-03-01

    ROC(S)SC(O)OCH2CH3, with R = CH3sbnd , (CH3)2CHsbnd and CH3(CH2)2sbnd , were obtained through the reaction between potassium xanthate salts, ROC(S)SK, and ethyl chloroformate, ClC(O)OCH2CH3. The liquid compounds were identified and characterized by 1H and 13C NMR and mass spectrometry. The conformations adopted by the molecules were studied by DFT methods. 6 conformers were theoretically predicted for R = CH3sbnd and (CH3)2CHsbnd , while the conformational flexibility of the n-propyl substituent increases the total number of feasible rotamers to 21. For the three molecules, the conformers can be associated in 3 groups, being the most stable the AS forms - the Cdbnd S double bond anti (A) with respect to the Csbnd S single bond and the Ssbnd C single bond syn (S) with respect to the Cdbnd O double bond - followed by AA and SS conformers. The vibrational spectra were interpreted in terms of the predicted conformational equilibrium, presenting the ν(Cdbnd O) spectral region signals corresponding to the three groups of conformers. A moderated pre-resonance Raman enhancement of the ν(Cdbnd S) vibrational mode of CH3(CH2)2OC(S)SC(O)OCH2CH3 was detected, when the excitation radiation approaches the energy of a n → π∗ electronic transition associated with the Cdbnd S chromophore. UV-visible spectra in different solvents were measured and interpreted in terms of TD-DFT calculations. The unknown molecule CH3CH2OC(O)SH was isolated by the UV-visible photolysis of CH3OC(S)SC(O)OCH2CH3 isolated in Ar matrix, and also obtained as a side-product of the reaction between potassium xanthate salts, ROC(S)SK, and ethyl chloroformate, ClC(O)OCH2CH3.

  18. Atmospheric Chemistry of (CF3)2CHOCH3, (CF3)2CHOCHO, and CF3C(O)OCH3.

    PubMed

    Østerstrøm, Freja From; Wallington, Timothy J; Sulbaek Andersen, Mads P; Nielsen, Ole John

    2015-10-22

    Smog chambers with in situ FTIR detection were used to measure rate coefficients in 700 Torr of air and 296 ± 2 K of: k(Cl+(CF3)2CHOCH3) = (5.41 ± 1.63) × 10(-12), k(Cl+(CF3)2CHOCHO) = (9.44 ± 1.81) × 10(-15), k(Cl+CF3C(O)OCH3) = (6.28 ± 0.98) × 10(-14), k(OH+(CF3)2CHOCH3) = (1.86 ± 0.41) × 10(-13), and k(OH+(CF3)2CHOCHO) = (2.08 ± 0.63) × 10(-14) cm(3) molecule(-1) s(-1). The Cl atom initiated oxidation of (CF3)2CHOCH3 gives (CF3)2CHOCHO in a yield indistinguishable from 100%. The OH radical initiated oxidation of (CF3)2CHOCH3 gives the following products (molar yields): (CF3)2CHOCHO (76 ± 8)%, CF3C(O)OCH3 (16 ± 2)%, CF3C(O)CF3 (4 ± 1)%, and C(O)F2 (45 ± 5)%. The primary oxidation product (CF3)2CHOCHO reacts with Cl atoms to give secondary products (molar yields): CF3C(O)CF3 (67 ± 7)%, CF3C(O)OCHO (28 ± 3)%, and C(O)F2 (118 ± 12)%. CF3C(O)OCH3 reacts with Cl atoms to give: CF3C(O)OCHO (80 ± 8)% and C(O)F2 (6 ± 1)%. Atmospheric lifetimes of (CF3)2CHOCH3, (CF3)2CHOCHO, and CF3C(O)OCH3 were estimated to be 62 days, 1.5 years, and 220 days, respectively. The 100-year global warming potentials (GWPs) for (CF3)2CHOCH3, (CF3)2CHOCHO, and CF3C(O)OCH3 are estimated to be 6, 121, and 46, respectively. A comprehensive description of the atmospheric fate of (CF3)2CHOCH3 is presented. PMID:26439469

  19. The effect of VUV radiation from Ar/O2 plasmas on low-k SiOCH films

    NASA Astrophysics Data System (ADS)

    Lee, J.; Graves, D. B.

    2011-08-01

    The degradation of porous low-k materials, like SiOCH, under plasma processing continues to be a problem in the next generation of integrated-circuit fabrication. Due to the exposure of the film to many species during plasma treatment, such as photons, ions, radicals, etc, it is difficult to identify the mechanisms responsible for plasma-induced damage. Using a vacuum beam apparatus with a calibrated Xe vacuum ultraviolet (VUV) lamp, we show that 147 nm VUV photons and molecular O2 alone can damage these low-k materials. Using Fourier-transform infrared (FTIR) spectroscopy, we show that VUV/O2 exposure causes a loss of methylated species, resulting in a hydrophilic, SiOx-like layer that is susceptible to H2O absorption, leading to an increased dielectric constant. The effect of VUV radiation on chemical modification of porous SiOCH films in the vacuum beam apparatus and in Ar and O2 plasma exposure was found to be a significant contributor to dielectric damage. Measurements of dielectric constant change using a mercury probe are consistent with chemical modification inferred from FTIR analysis. Furthermore, the extent of chemical modification appears to be limited by the penetration depth of the VUV photons, which is dependent on wavelength of radiation. The creation of a SiOx-like layer near the surface of the material, which grows deeper as more methyl is extracted, introduces a dynamic change of VUV absorption throughout the material over time. As a result, the rate of methyl loss is continuously changing during the exposure. We present a model that attempts to capture this dynamic behaviour and compare the model predictions to experimental data through a fitting parameter that represents the effective photo-induced methyl removal. While this model accurately simulates the methyl loss through VUV exposure by the Xe lamp and Ar plasma, the methyl loss from VUV photons in O2 plasma are only accurately depicted at longer exposure times. We conclude that other

  20. Analysis of the kinetics and yields of OH radical production from the CH3OCH2 + O2 reaction in the temperature range 195-650 K: an experimental and computational study.

    PubMed

    Eskola, A J; Carr, S A; Shannon, R J; Wang, B; Blitz, M A; Pilling, M J; Seakins, P W; Robertson, S H

    2014-08-28

    The methoxymethyl radical, CH3OCH2, is an important intermediate in the low temperature combustion of dimethyl ether. The kinetics and yields of OH from the reaction of the methoxymethyl radical with O2 have been measured over the temperature and pressure ranges of 195-650 K and 5-500 Torr by detecting the hydroxyl radical using laser-induced fluorescence following the excimer laser photolysis (248 nm) of CH3OCH2Br. The reaction proceeds via the formation of an energized CH3OCH2O2 adduct, which either dissociates to OH + 2 H2CO or is collisionally stabilized by the buffer gas. At temperatures above 550 K, a secondary source of OH was observed consistent with thermal decomposition of stabilized CH3OCH2O2 radicals. In order to quantify OH production from the CH3OCH2 + O2 reaction, extensive relative and absolute OH yield measurements were performed over the same (T, P) conditions as the kinetic experiments. The reaction was studied at sufficiently low radical concentrations (∼10(11) cm(-3)) that secondary (radical + radical) reactions were unimportant and the rate coefficients could be extracted from simple bi- or triexponential analysis. Ab initio (CBS-GB3)/master equation calculations (using the program MESMER) of the CH3OCH2 + O2 system were also performed to better understand this combustion-related reaction as well as be able to extrapolate experimental results to higher temperatures and pressures. To obtain agreement with experimental results (both kinetics and yield data), energies of the key transition states were substantially reduced (by 20-40 kJ mol(-1)) from their ab initio values and the effect of hindered rotations in the CH3OCH2 and CH3OCH2OO intermediates were taken into account. The optimized master equation model was used to generate a set of pressure and temperature dependent rate coefficients for the component nine phenomenological reactions that describe the CH3OCH2 + O2 system, including four well-skipping reactions. The rate coefficients were

  1. Disproportionation and thermochemical sulfate reduction reactions in S-H20-Ch4 and S-D2O-CH4 systems from 200 to 340 °C at elevated pressures

    USGS Publications Warehouse

    Yuan, Shunda; Chou, I-Ming; Burruss, Robert A.

    2013-01-01

    Elemental sulfur, as a transient intermediate compound, by-product, or catalyst, plays significant roles in thermochemical sulfate reduction (TSR) reactions. However, the mechanisms of the reactions in S-H2O-hydrocarbons systems are not clear. To improve our understanding of reaction mechanisms, we conducted a series of experiments between 200 and 340 °C for S-H2O-CH4, S-D2O-CH4, and S-CH4-1m ZnBr2 systems in fused silica capillary capsules (FSCC). After a heating period ranging from 24 to 2160 hours (hrs), the quenched samples were analyzed by Raman spectroscopy. Combined with the in situ Raman spectra collected at high temperatures and pressures in the S-H2O and S-H2O-CH4 systems, our results showed that (1) the disproportionation of sulfur in the S-H2O-CH4 system occurred at temperatures above 200 °C and produced H2S, SO42-, and possibly trace amount of HSO4-; (2) sulfate (and bisulfate), in the presence of sulfur, can be reduced by methane between 250 and 340 °C to produce CO2 and H2S, and these TSR temperatures are much closer to those of the natural system (2O-CH4 system may take place simultaneously, with TSR being favored at higher temperatures; and (4) in the system S-D2O-CH4, both TSR and the competitive disproportionation reactions occurred simultaneously at temperatures above 300 °C, but these reactions were very slow at lower temperatures. Our observation of methane reaction at 250 °C in a laboratory time scale suggests that, in a geologic time scale, methane may be destroyed by TSR reactions at temperatures > 200 °C that can be reached by deep drilling for hydrocarbon resources.

  2. Anticancer activity of Panax notoginseng extract 20(S)-25-OCH3-PPD: Targetting beta-catenin signalling.

    PubMed

    Bi, Xiuli; Zhao, Yuqing; Fang, Wenfeng; Yang, Wancai

    2009-11-01

    1. The Wnt/beta-catenin pathway plays a critical role in carcinogenesis and so agents that target Wnt/beta-catenin may have potential in cancer prevention and therapy. The aim of the present study was to evaluate the anticancer activity of the novel natural product dammarane-type triterpene sapogenin (20(S)-25-OCH3-PPD; PPD25) isolated from the leaves of Panax notoginseng. 2. The anticancer activity of PPD25 was evaluated in three colon cancer cell lines and in one lung cancer cell line. The effects of PPD25 to inhibit proliferation and to induce apoptosis were evaluated. In addition, the potential mechanisms underlying the effects of PPD25 were investigated. 3. It was found that the addition of 5 or 25 micromol/L PPD25 to the culture medium significantly inhibited cell proliferation and induced apoptosis in all four cancer cell lines. Mechanistic studies revealed that PPD25 significantly reduced the expression of beta-catenin, a key mediator in the Wnt pathway, as well as transcriptional targets of beta-catenin, namely c-myc, cyclin D1, cdk4 and T cell factor (TCF)-4. In addition, beta-catenin/TCF transcriptional activity was significantly suppressed by PPD25. 4. The data demonstrate that the PPD25 exerts its anticancer effect by targetting beta-catenin signalling, suggesting that PPD25 may have potential as a chemotherapeutic and/or chemopreventive agent for colon and lung cancer. PMID:19413587

  3. Investigation of the O+allyl addition/elimination reaction pathways from the OCH{sub 2}CHCH{sub 2} radical intermediate

    SciTech Connect

    FitzPatrick, Benjamin L.; Lau, K.-C.; Butler, Laurie J.; Lee, S.-H.; Lin, Jim Jr-Min

    2008-08-28

    These experiments study the preparation of and product channels resulting from OCH{sub 2}CHCH{sub 2}, a key radical intermediate in the O+allyl bimolecular reaction. The data include velocity map imaging and molecular beam scattering results to probe the photolytic generation of the radical intermediate and the subsequent pathways by which the radicals access the energetically allowed product channels of the bimolecular reaction. The photodissociation of epichlorohydrin at 193.3 nm produces chlorine atoms and c-OCH{sub 2}CHCH{sub 2} radicals; these undergo a facile ring opening to the OCH{sub 2}CHCH{sub 2} radical intermediate. State-selective resonance-enhanced multiphoton ionization (REMPI) detection resolves the velocity distributions of ground and spin-orbit excited state chlorine independently, allowing for a more accurate determination of the internal energy distribution of the nascent radicals. We obtain good agreement detecting the velocity distributions of the Cl atoms with REMPI, vacuum ultraviolet (VUV) photoionization at 13.8 eV, and electron bombardment ionization; all show a bimodal distribution of recoil kinetic energies. The dominant high recoil kinetic energy feature peaks near 33 kcal/mol. To elucidate the product channels resulting from the OCH{sub 2}CHCH{sub 2} radical intermediate, the crossed laser-molecular beam experiment uses VUV photoionization and detects the velocity distribution of the possible products. The data identify the three dominant product channels as C{sub 3}H{sub 4}O (acrolein)+H, C{sub 2}H{sub 4}+HCO (formyl radical), and H{sub 2}CO (formaldehyde)+C{sub 2}H{sub 3}. A small signal from C{sub 2}H{sub 2}O (ketene) product is also detected. The measured velocity distributions and relative signal intensities at m/e=27, 28, and 29 at two photoionization energies show that the most exothermic product channel, C{sub 2}H{sub 5}+CO, does not contribute significantly to the product branching. The higher internal energy onset of the

  4. A computational study of the addition of ReO3L (L = Cl(-), CH3, OCH3 and Cp) to ethenone.

    PubMed

    Aniagyei, Albert; Tia, Richard; Adei, Evans

    2016-01-01

    The periselectivity and chemoselectivity of the addition of transition metal oxides of the type ReO3L (L = Cl, CH3, OCH3 and Cp) to ethenone have been explored at the MO6 and B3LYP/LACVP* levels of theory. The activation barriers and reaction energies for the stepwise and concerted addition pathways involving multiple spin states have been computed. In the reaction of ReO3L (L = Cl(-), OCH3, CH3 and Cp) with ethenone, the concerted [2 + 2] addition of the metal oxide across the C=C and C=O double bond to form either metalla-2-oxetane-3-one or metalla-2,4-dioxolane is the most kinetically favored over the formation of metalla-2,5-dioxolane-3-one from the direct [3 + 2] addition pathway. The trends in activation and reaction energies for the formation of metalla-2-oxetane-3-one and metalla-2,4-dioxolane are Cp < Cl(-) < OCH3 < CH3 and Cp < OCH3 < CH3 < Cl(-) and for the reaction energies are Cp < OCH3 < Cl(-) < CH3 and Cp < CH3 < OCH3 < Cl CH3. The concerted [3 + 2] addition of the metal oxide across the C=C double of the ethenone to form species metalla-2,5-dioxolane-3-one is thermodynamically the most favored for the ligand L = Cp. The direct [2 + 2] addition pathways leading to the formations of metalla-2-oxetane-3-one and metalla-2,4-dioxolane is thermodynamically the most favored for the ligands L = OCH3 and Cl(-). The difference between the calculated [2 + 2] activation barriers for the addition of the metal oxide LReO3 across the C=C and C=O functionalities of ethenone are small except for the case of L = Cl(-) and OCH3. The rearrangement of the metalla-2-oxetane-3-one-metalla-2,5-dioxolane-3-one even though feasible, are unfavorable due to high activation energies of their rate-determining steps. For the rearrangement of the metalla-2-oxetane-3-one to metalla-2,5-dioxolane-3-one, the trends in activation barriers is found to follow the order OCH3 < Cl(-) < CH3 < Cp. The trends in the activation energies for

  5. Distribution of eukaryotic serine racemases in the bacterial domain and characterization of a representative protein in Roseobacter litoralis Och 149.

    PubMed

    Kubota, Takaaki; Shimamura, Shigeru; Kobayashi, Tohru; Nunoura, Takuro; Deguchi, Shigeru

    2016-01-01

    Two distinct bacterial and eukaryotic serine racemases (SRs) have been identified based on phylogenetic and biochemical characteristics. Although some reports have suggested that marine heterotrophic bacteria have the potential to produce d-serine, the gene encoding bacterial SRs is not found in those bacterial genomes. In this study, using in-depth genomic analysis, we found that eukaryotic SR homologues were distributed widely in various bacterial genomes. Additionally, we selected a eukaryotic SR homologue from a marine heterotrophic bacterium, Roseobacter litoralis Och 149 (RiSR), and constructed an RiSR gene expression system in Escherichia coli for studying the properties of the enzyme. Among the tested amino acids, the recombinant RiSR exhibited both racemization and dehydration activities only towards serine, similar to many eukaryotic SRs. Mg2+ and MgATP enhanced both activities of RiSR, whereas EDTA abolished these enzymatic activities. The enzymatic properties and domain structure of RiSR were similar to those of eukaryotic SRs, particularly mammalian SRs. However, RiSR showed lower catalytic efficiency for L-serine dehydration (kcat/Km=0.094 min(-1) mM(-1)) than those of eukaryotic SRs reported to date (kcat/Km=0.6-21 min(-1) mM(-1)). In contrast, the catalytic efficiency for L-serine racemization of RiSR (kcat/Km=3.14 min(-1) mM(-1)) was 34-fold higher than that of l-serine dehydration. These data suggested that RiSR primarily catalysed serine racemization rather than dehydration.

  6. Chemical and electrochemical oxidation of [Rh(β-diketonato)(CO)(P(OCH2)3CCH3)]: an experimental and DFT study.

    PubMed

    Erasmus, Johannes J C; Conradie, Jeanet

    2013-06-28

    An experimental and computational chemistry study of the reactivity of [Rh(β-diketonato)(CO)(P(OCH2)3CCH3)] complexes towards chemical and electrochemical oxidation shows that more electron withdrawing groups on the β-diketonato ligand reduce electron density on the rhodium atom to a larger extent than electron donating groups. This leads to a slower second-order oxidative addition rate, k1, and a higher electrochemical oxidation potential, E(pa)(Rh), linearly related by ln k1 = -11(1) E(pa)(Rh) - 2.3(5). The reactivity of these complexes can be predicted by their DFT calculated HOMO energies: E(HOMO) = -0.34(8)E(pa)(Rh) - 5.04(4) = 0.032(5) ln k1- 4.96(4). k1 of [Rh(β-diketonato)(CO)(P(OCH2)3CCH3)] complexes is slower than that of related [Rh(β-diketonato)(CO)(PPh3)] and [Rh(β-diketonato)(P(OPh)3)2] complexes due to the better π-acceptor ability of the CO-phosphite-rhodium combination than that of CO-PPh3-rhodium or di-phosphite-rhodium. PMID:23632432

  7. Rotational Spectrum, Conformational Composition, and Quantum Chemical Calculations of Cyanomethyl Formate (HC(O)OCH2C≡N), a Compound of Potential Astrochemical Interest.

    PubMed

    Samdal, Svein; Møllendal, Harald; Carles, Sophie

    2015-08-27

    The rotational spectrum of cyanomethyl formate (HC(O)OCH2C≡N) has been recorded in the 12–123 GHz spectral range. The spectra of two conformers were assigned. The rotamer denoted I has a symmetry plane and two out-of plane hydrogen atoms belonging to the cyanomethyl (CH2CN) moiety. In the conformer called II, the cyanomethyl group is rotated 80.3° out of this plane. Conformer I has an energy that is 1.4(6) kJ/mol lower than the energy of II according to relative intensity measurements. A large number of rotational transitions have been assigned for the ground and vibrationally excited states of the two conformers and accurate spectroscopic constants have been obtained. These constants should predict frequencies of transitions outside the investigated spectral range with a very high degree of precision. It is suggested that cyanomethyl formate is a potential interstellar compound. This suggestion is based on the fact that its congener methyl formate (HC(O)OCH3) exists across a large variety of interstellar environments and the fact that cyanides are very prevalent in the Universe. The experimental work has been augmented by high-level quantum chemical calculations. The CCSD/cc-pVQZ calculations are found to predict structures of the two forms that are very close to the Born–Oppenheimer equilibrium structures. MP2/cc-pVTZ predictions of several vibration–rotation interaction constants were generally found to be rather inaccurate. A gas-phase reaction between methyl formate and the cyanomethyl radical CH2CN to produce a hydrogen atom and cyanomethyl formate was mimicked using MP2/cc-pVTZ calculations. It was found that this reaction is not favored thermodynamically. It is also conjectured that the possible formation of cyanomethyl formate might be catalyzed and take place on interstellar particles. PMID:26207519

  8. Evaluation of a Novel Approach for Peptide Sequencing: Laser-induced Acoustic Desorption Combined with P(OCH3)2+ Chemical Ionization and Collision-activated Dissociation in a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer

    PubMed Central

    Somuramasami, Jayalakshmi; Kenttämaa, Hilkka I.

    2007-01-01

    A novel mass spectrometric method has been developed for obtaining sequence information on small peptides. The peptides are desorbed as intact neutral molecules into a Fourier transform ion cyclotron resonance mass spectrometer (FT-ICR) by means of laser-induced acoustic desorption (LIAD). Reactions of the neutral peptides with the dimethoxyphosphenium ion, P(OCH3)2+, occur predominantly by addition of the peptide to P(OCH3)2+ followed by the loss of two methanol molecules, thus yielding product ions with the composition (peptide + P − 2H)+. Upon sustained off-resonance irradiation for collision-activated dissociation (SORI-CAD), the (peptide + P − 2H)+ ions undergo successive losses of CO and NH = CHR or H2O, CO, and NH = CHR to yield sequence-related fragment ions in addition to the regular an- and bn-type ions. Under the same conditions, SORI-CAD of the analogous protonated peptides predominantly yields the regular an- and bn-type ions. The mechanisms of the reactions of peptides with P(OCH3)2+ and the dissociation of the (peptide + P − 2H)+ ions were examined by using model peptides and molecular orbital calculations. PMID:17157527

  9. H2O-CH4 and H2S-CH4 complexes: a direct comparison through molecular beam experiments and ab initio calculations.

    PubMed

    Cappelletti, David; Bartocci, Alessio; Frati, Federica; Roncaratti, Luiz F; Belpassi, Leonardo; Tarantelli, Francesco; Lakshmi, Prabha Aiswarya; Arunan, Elangannan; Pirani, Fernando

    2015-11-11

    New molecular beam scattering experiments have been performed to measure the total (elastic plus inelastic) cross sections as a function of the velocity in collisions between water and hydrogen sulfide projectile molecules and the methane target. Measured data have been exploited to characterize the range and strength of the intermolecular interaction in such systems, which are of relevance as they drive the gas phase molecular dynamics and the clathrate formation. Complementary information has been obtained by rotational spectra, recorded for the hydrogen sulfide-methane complex, with a pulsed nozzle Fourier transform microwave spectrometer. Extensive ab initio calculations have been performed to rationalize all the experimental findings. The combination of experimental and theoretical information has established the ground for the understanding of the nature of the interaction and allows for its basic components to be modelled, including charge transfer, in these weakly bound systems. The intermolecular potential for H2S-CH4 is significantly less anisotropic than for H2O-CH4, although both of them have potential minima that can be characterized as 'hydrogen bonded'.

  10. Plasma damage mechanisms for low-k porous SiOCH films due to radiation, radicals, and ions in the plasma etching process

    SciTech Connect

    Uchida, Saburo; Takashima, Seigo; Hori, Masaru; Fukasawa, Masanaga; Ohshima, Keiji; Nagahata, Kazunori; Tatsumi, Tetsuya

    2008-04-01

    Low dielectric constant (low-k) films have been widely used as insulating materials in ultra-large-scale integrated circuits. Low-k films receive heavy damage during the plasma processes of etching or ashing, resulting in an increase in their dielectric constant. In order to realize damage-free plasma processes for low-k films, it is essential to determine the influence of radiation, radicals, and ions emitted in the plasma process on the characteristics of low-k films. We have developed a technique to evaluate the influence of radiation, radicals, ions, and their synergies on films in real plasma processes and have named it pallet for plasma evaluation (PAPE). Using the PAPE, plasma-induced damage on porous SiOCH films were investigated in dual-frequency capacitively coupled H{sub 2}/N{sub 2} plasmas. The damage was characterized by ellipsometry, Fourier-transform infrared spectroscopy, and thermal desorption spectroscopy. On the basis of the results, the damage mechanisms associated with vacuum ultraviolet (VUV) and UV radiation, radicals, and ions were clarified. The damage was caused not only by ions and radicals but also by VUV and UV radiation emitted by the plasmas. Moreover, it was found that the synergy between the radiation and the radicals enhanced the damage.

  11. Investigating the H2-He-H2O-CH4 equation of state in the deep troposphere of Jupiter

    NASA Astrophysics Data System (ADS)

    Karpowicz, Bryan M.; Steffes, Paul G.

    2013-03-01

    In this work, a new equation of state for a H2-He-H2O-CH4 mixture is presented. The equation is optimized for the deep jovian atmosphere (∼100 bars) where the NASA Juno Microwave Radiometer (MWR) will probe. The methodology used is based upon that of Lemmon and Jacobsen (Lemmon, E.W., Jacobsen, R.T. [2004]. J. Phys. Chem. Ref. Data 33, 593-+) and Kunz et al. (Kunz, O., Klimeck, R., Wagner, W., Jaeschke, M. [2006]. Technical Monograph, VDI-Verlag). This methodology is used in combination with available published thermodynamic measurements and with new pressure-Volume-Temperature (pVT) measurements of H2-H2O mixtures conducted with the jovian simulator described in Karpowicz and Steffes (Karpowicz, B.M., Steffes, P.G. [2011]. Icarus 212, 210-223). In addition to being necessary to interpret laboratory measurements, the new equation of state is important in developing temperature pressure profiles of the deep jovian atmosphere. This is demonstrated by incorporating the new equation of state into an updated version of the DeBoer (DeBoer, D.R. [1995]. Ph.D. Thesis, Georgia Institute of Technology) Thermo-Chemical Model (TCM), and viewing its effect on the resulting simulated jovian atmospheric profiles.

  12. Surface photoelectric and visible light driven photocatalytic properties of zinc antimonate-based photocatalysts

    SciTech Connect

    Wu, Shaojun; Li, Guoqiang; Zhang, Yang; Zhang, Weifeng

    2013-03-15

    Highlights: ► N-doped and pristine ZnSb{sub 2}O{sub 6} photocatalysts were synthesized by a facile method. ► N-doped ZnSb{sub 2}O{sub 6} shows a significant enhanced visible light photocatalytic activity. ► The N-doped ZnSb{sub 2}O{sub 6} shows the reduced surface photovoltage signals. - Abstract: The N-doped and pristine ZnSb{sub 2}O{sub 6} photocatalysts were synthesized by a facile method. The samples were characterized by X-ray diffraction (XRD), UV–vis spectroscopy, surface photovoltage spectroscopy and scanning electron microscopy. The photocatalytic activities of the prepared samples were evaluated from the degradation of rhodamine B (RhB) under full arc and visible light irradiation of Xe lamp. The XRD and UV–vis results indicated that the N-doping did not change the crystal structure, but decrease the band gap in comparison with the pristine one. The N-doped ZnSb{sub 2}O{sub 6} shows the reduced surface photovoltage signals and the significantly enhanced photocatalytic activity under two irradiation conditions.

  13. Singlet Mechanism for Trans → Cis Photoisomerization of Quaternary Salts of 4-Substituted 4'-Azastilbenes (R = CN, H, CH3, and OCH3) and their Quinolinium Analogues. VIII

    NASA Astrophysics Data System (ADS)

    Görner, H.; Fojtik, A.; Wróblewski, J.; Currell, L. J.

    1985-05-01

    The trans → cis photoisomerization of a series of substituted stilbazolium salts (At+X- , At+: trans-1-alkyl-4-[4-R-styryl]-pyridinium and -quinolinium, R = CN. H, CH3 and OCH3, X- = I and ClO4-) was studied by laser flash photolysis and steady state irradiation measurements. The quantum yields of cis ⇄ trans photoisomerization (ϕc → t and ϕt → c ) and of fluorescence of the trans isomers (ϕf) were determined in several solvents at room temperature and at low temperatures in mixtures of either 2-methyltetrahydrofuran-dichloromethane or ethanolmethanol (E-M). In polar solvents at room temperature ϕt → c is substantial ( ≧ 0.3) and ϕf is small (10-3-10-2). Competition of fluorescence and an activated step in the trans → cis pathway is indicated by the effects of temperature on ϕf and ϕt → c (activation energy: 2 - 3 kcal/mol). A transient, observed only at low temperatures (lifetime τT > 0.5 ms in E-M below -170°C), is assigned to the lowest triplet state with trans configuration. On the basis of the effects of temperature on ϕf, ϕt → c , and the triplet yield and those of quenchers on ϕf and ϕt → c , involvement of the triplet state in the twisting process at room temperature is excluded. Therefore, a singlet mechanism is suggested for the trans → cis photoisomerization of the stilbazolium salts examined. Significant reduction of ϕt → c for iodides in solvents of moderate polarity, where ion pairs are present, is accounted for by photoinduced electron transfer in competition to trans → cis photoisomerization.

  14. Correlation between stress-induced leakage current and dielectric degradation in ultra-porous SiOCH low-k materials

    SciTech Connect

    Wu, C. De Wolf, I.; Li, Y.; Leśniewska, A.; Varela Pedreira, O.; Marneffe, J.-F. de; Ciofi, I.; Verdonck, P.; Baklanov, M. R.; Bömmels, J.; Tőkei, Zs.; Croes, K.

    2015-10-28

    Stress-Induced Leakage Current (SILC) behavior during the dielectric degradation of ultra-porous SiOCH low-k materials was investigated. Under high voltage stress, SILC increases to a critical value before final hard breakdown. This SILC increase rate is mainly driven by the injected charges and is negligibly influenced by temperature and voltage. SILC is found to be transient and shows a t{sup −1} relaxation behavior, where t is the storage time at low voltages. This t{sup −1} transient behavior, described by the tunneling front model, is caused by both electron charging of neutral defects in the dielectric close to the cathode interface and discharging of donor defects close to the anode interface. These defects have a uniform density distribution within the probed depth range, which is confirmed by the observed flat band voltage shift results collected during the low voltage storage. By applying an additional discharging step after the low voltage storage, the trap energies and spatial distributions are derived. In a highly degraded low-k dielectric, the majority of defects have a trap depth between 3.4 eV and 3.6 eV and a density level of 1 × 10{sup 18 }eV{sup −1 }cm{sup −3}. The relation between the defect density N and the total amount of the injected charges Q is measured to be sub-linear, N ∼ Q{sup 0.45±0.07}. The physical nature of these stress-induced defects is suggested to be caused by the degradation of the Si-O based skeleton in the low-k dielectric.

  15. Design of peptides with α, β-dehydro-residues: synthesis and crystal structure of a tripeptide N-benzyloxycarbonyl-ΔVal-ΔPhe- L-Ala-OCH 3

    NASA Astrophysics Data System (ADS)

    Goel, Vijay Kumar; Dey, Sharmistha; Singh, Tej P.

    2005-03-01

    In order to develop the design rules for producing specific conformations of peptides with α, β-dehydro-residues a peptide Cbz-ΔVal-ΔPhe-Ala-OCH 3 was synthesized in solution phase. The crystal structure has been determined by X-ray diffraction method. The structure was refined to an R-value of 0.050. The peptide adopts a type I β-turn conformation with backbone torsion angles of two corner residues, ϕ1=-53.9(6)°, ψ1=-33.0(6)°, ϕ2=-73.7(5)° and ψ2=-12.2(6)°. The conformation is stabilized by an intramolecular 4→1 hydrogen bond involving NH of Ala residue as a donor and carbonyl oxygen atom of Cbz group as an acceptor. The torsion angles, χ11,1=172.8(6) and χ11,2=-6.9(9) of ΔVal residue indicate that its side chain is planar while the torsion angles, χ21=-9.0(9), χ22,1=-43.4(10) and χ22,2=130.1(9) show that the side chain of ΔPhe deviates considerably from the planarity. This is the first sequence in which ΔVal and ΔPhe are introduced at adjacent positions and the structure reveals clearly that the side chain of ΔPhe is a relatively less rigid than that of ΔVal. The molecules are packed in columns parallel to c-axis.

  16. Correlation between stress-induced leakage current and dielectric degradation in ultra-porous SiOCH low-k materials

    NASA Astrophysics Data System (ADS)

    Wu, C.; Li, Y.; Leśniewska, A.; Varela Pedreira, O.; de Marneffe, J.-F.; Ciofi, I.; Verdonck, P.; Baklanov, M. R.; Bömmels, J.; De Wolf, I.; Tőkei, Zs.; Croes, K.

    2015-10-01

    Stress-Induced Leakage Current (SILC) behavior during the dielectric degradation of ultra-porous SiOCH low-k materials was investigated. Under high voltage stress, SILC increases to a critical value before final hard breakdown. This SILC increase rate is mainly driven by the injected charges and is negligibly influenced by temperature and voltage. SILC is found to be transient and shows a t-1 relaxation behavior, where t is the storage time at low voltages. This t-1 transient behavior, described by the tunneling front model, is caused by both electron charging of neutral defects in the dielectric close to the cathode interface and discharging of donor defects close to the anode interface. These defects have a uniform density distribution within the probed depth range, which is confirmed by the observed flat band voltage shift results collected during the low voltage storage. By applying an additional discharging step after the low voltage storage, the trap energies and spatial distributions are derived. In a highly degraded low-k dielectric, the majority of defects have a trap depth between 3.4 eV and 3.6 eV and a density level of 1 × 1018 eV-1 cm-3. The relation between the defect density N and the total amount of the injected charges Q is measured to be sub-linear, N ˜ Q0.45±0.07. The physical nature of these stress-induced defects is suggested to be caused by the degradation of the Si-O based skeleton in the low-k dielectric.

  17. Theoretical studies in local coordination and vibrational spectra of M +CH 3O(CH 2CH 2O) nCH 3 ( n = 2-7) complexes (M = Na, K, Mg and Ca)

    NASA Astrophysics Data System (ADS)

    Dhumal, Nilesh R.; Gejji, Shridhar P.

    2006-04-01

    Solid polymer electrolytes (SPE) comprised of poly(ethylene oxide) (PEO) oligomers complexed with alkali metal salt of weakly coordinating anions have been of a great interest due to their high ionic conductivity. Ion pair formation influence the number of charge carriers and is an important factor underlying the ion transport phenomenon. In this work, the electronic structure and vibrational spectra of the metal ion-PEO oligomer represented by M-CH 3O(CH 2CH 2O) nCH 3 ( n = 2-7) (M = Na +, K +, Mg 2+ and Ca 2+) are obtained by employing the ab initio and hybrid density functional methods. Structural and spectral consequences of PEO oligomers to the alkali- and alkaline earth-metal ion coordination in different chemical environments have been presented. In metal ion-PEO oligomer ion-pairs the Mg 2+ ion binds strongly to ether oxygens of polyether complexes. The density functional calculations predict the heptaglyme ( n = 7 in the above series) binds strongly to the metal ion. The frequency shifts of characteristics vibrations induced by the metal ion-coordination in CH 3O(CH 2CH 2O) nCH 3-M ( n = 2-7) complexes have been discussed.

  18. Fluid evolution in the H 2O-CH 4-CO 2-NaCl system during emerald mineralization at Gravelotte, Murchison Greenstone Belt, Northeast Transvaal, South Africa

    NASA Astrophysics Data System (ADS)

    Nwe, Yin Yin; Morteani, Giulio

    1993-01-01

    Fluid evolution during emerald mineralization at the Gravelotte emerald mine has been studied by microthermometry and laser Raman microprobe spectrometry. The emeralds and associated phenakites occur on the flanks of a highly metasomatised albitite pegmatoid body and in the biotite schists at and near its contact. The fluids lie in the H 2O-CH 4-CO 2-NaCl system and four types of inclusions are characterised based on time of trapping and fluid contents. The earliest type 1 inclusions, found in phenakites and the emeralds which formed from them, are low salinity (<6 wt% NaCl) with up to 18 mol% CH 4. The carbonic phase contains over 93 mol% CH 4 and variable small amounts of CO 2, C 2H 6, N 2, and H 2S. The solvus crest for this system lies at ≈400°C, closer to the H 2O end of the join. With time the fluids become less CH 4 rich and more saline. The type 2 fluids are highly variable in both CH 4-CO 2 contents and salinity, reflecting mixing of type 1 fluids with higher salinity brines. The late type 3 and 4 inclusions are CH 4-CO 2-free high salinity inclusions with up to 38 wt% NaCl. Trapping conditions for the type 1 fluids were around 450-500°C and 4 kb based on model isochores and geologic evidence. During the trapping of type 2 inclusions, fluid pressures probably fluctuated due to opening and resealing of fractures. Approximate P- T ranges of trapping for these and other later inclusions have been defined, minimum trapping temperatures for types 2, 3, and 4 being, respectively, 250, 150, and 240°C, and pressures in the range of 1-4 kb. Calculations of ƒ O 2 show an initial low ƒ O 2 between QFM and the synthetic graphite-CH 4 buffer for the type 1 fluids. This rises to above QFM in the later stages. Such low initial values are uncharacteristic of granitic pegmatite systems, and it is suggested that the phenakites formed in the post-magmatic stage of alkali metasomatism when the albitization took place. In the later stages, phenakite was converted to

  19. Degenerate electrical conductive and excitonic photoluminescence properties of epitaxial films of wide gap p-type layered oxychalcogenides, LnCuOCh (Ln=La, Pr and Nd; Ch=S or Se)

    NASA Astrophysics Data System (ADS)

    Hiramatsu, H.; Ueda, K.; Takafuji, K.; Ohta, H.; Hirano, M.; Kamiya, T.; Hosono, H.

    Electrical and photoluminescence properties were investigated for epitaxial films of layered oxychalcogenides, LnCuOCh (Ln=La, Pr, and Nd, Ch=S or Se). Epitaxial films of Mg 10 at.% doped LaCuOS1-xSex are the first demonstration of degenerate conduction with high hole concentration >1020 cm-3 in wide gap p-type semiconductors. Ion substitution varied the excitonic emission energy from 3.21 eV to 2.89 eV while lanthanide and chalcogenide ion substitutions displayed the opposite tendency against cell volume. These unique properties are discussed with respect to the electronic structure originating from the layered crystal structure.

  20. Transfer of Amide and 2-Methoxyethoxy Groups and Sodium Encapsulation in the Reaction of TaCl3[N(TMS)2]2 with Sodium Bis(2-methoxyethoxy)aluminum Hydride: X-ray Structure of [NaAl{N(TMS)2}(OCH2CH2OMe)3]2

    SciTech Connect

    Huang, Shih-Huang Huang; Wang, Xiaoping; Richmond, Michael G.

    2009-01-01

    The reaction between the tantalum compound TaCl3[N(TMS)2]2 and the hydridic reducing agent sodium bis(2-methoxyethoxy)aluminum hydride (Vitride) has been investigated in toluene solution at room temperature and found to afford the dimeric aluminate complex [NaAl{N(TMS)2}(OCH2CH2OMe)3]2 as the sole isolable product. The molecular structure of the product establishes the existence of a four-coordinate aluminum atom and the formal transfer of the 2-methoxyethoxy and bis(trimethylsilyl)amide groups to the aluminate product. The aggregation of two NaAl{N(TMS)2}(OCH2CH2OMe)3 units serves to bind the two sodium cations in a crown-ether fashion through six ancillary oxygen atoms.

  1. VAPOR PRESSURES, LIQUID MOLAR VOLUMES, VAPOR NON- IDEALITIES, AND CRITICAL PROPERTIES OF SOME FLUORINATED ETHERS: CF3OCF2OCF3, CF3OCF2 CF2H, c-CF2CF2CF2O, CF3OCF2H, AND CF3OCH3; AND OF CCl3F AND CF2ClH

    EPA Science Inventory

    Vapor pressures, compressibilities, expansivities, and molar volumes of the liquid phase have been measured between room temperature and the critical temperature for a series of fluorinated ethers: CF3OCF2OCF3, CF3OCF2CF2H, c-CF2CF2CF2O, CF3OCF2H, and CF3OCH3. Vapor-phase non-ide...

  2. [Ni(OH)3W6O18(OCH2)3CCH2OH]4–: the first tris-functionalized Anderson-type heteropolytungstate† †Electronic supplementary information (ESI) available: Experimental procedures, synthesis details, characterization data, including IR, ESI-MS, TGA, elemental analysis and X-ray crystallography with CIF file. CCDC 1477611. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6cc04326g Click here for additional data file. Click here for additional data file.

    PubMed Central

    Gumerova, Nadiia I.; Roller, Alexander

    2016-01-01

    Na2[TMA]2[Ni(OH)3W6O18(OCH2)3CCH2OH]·9H2O represents the first covalent tris-functionalized Anderson-type heteropolytungstate and was characterized by single-crystal X-ray diffraction, electrospray ionization mass spectrometry, TGA and IR spectroscopy. Zeta potential measurements in solutions containing human serum albumin were performed to investigate electrostatic interactions with [Ni(OH)3W6O18(OCH2)3CCH2OH]4–. PMID:27355393

  3. Synthesis and characterization of a new monophosphate (5-Cl-2,4-(OCH{sub 3}){sub 2}C{sub 6}H{sub 2}NH{sub 3})H{sub 2}PO{sub 4}

    SciTech Connect

    Kefi, R.; Abid, S.; Nasr, C. Ben . E-mail: cherif.bennasr@fsb.rnu.tn; Rzaigui, M.

    2007-03-22

    Chemical preparation, crystal structure and NMR spectroscopy of a new organic cation 5-chloro(2,4-dimethoxy)anilinium monophosphate H{sub 2}PO{sub 4} are given. This new compound crystallizes in the monoclinic system, with the space group P2{sub 1}/c and the following parameters: a=5.524(2)A, b=9.303(2)A, c=23.388(2)A, {beta}=90.66(4), V=1201.8(2)A{sup 3}, Z=4 and D{sub x}=1.573gcm{sup -3}. Crystal structure has been determined and refined to R=0.031 and R{sub w}=0.080 using 1702 independent reflections. Structure can be described as an infinite (H{sub 2}PO{sub 4}){sub n}{sup n-} corrugated chains in the a-direction. The organic groups (5-Cl-2,4-(OCH{sub 3}){sub 2}C{sub 6}H{sub 2}NH{sub 3}){sup +} are anchored between adjacent polyanions through multiple hydrogen bonds. This compound is also investigated by IR, thermal, and solid-state, {sup 13}C, {sup 31}P MAS NMR spectroscopies.

  4. Crystallization and preliminary crystallographic characterization of LmACR2, an arsenate/antimonate reductase from Leishmania major.

    PubMed

    Bisacchi, Davide; Zhou, Yao; Rosen, Barry P; Mukhopadhyay, Rita; Bordo, Domenico

    2006-10-01

    Arsenic is present in the biosphere owing either to the presence of pesticides and herbicides used in agricultural and industrial activities or to leaching from geological formations. The health effects of prolonged exposure to arsenic can be devastating and may lead to various forms of cancer. Antimony(V), which is chemically very similar to arsenic, is used instead in the treatment of leishmaniasis, an infection caused by the protozoan parasite Leishmania sp.; the reduction of pentavalent antimony contained in the drug Pentostam to the active trivalent form arises from the presence in the Leishmania genome of a gene, LmACR2, coding for the protein LmACR2 (14.5 kDa, 127 amino acids) that displays weak but significant sequence similarity to the catalytic domain of Cdc25 phosphatase and to rhodanese enzymes. For structural characterization, LmACR2 was overexpressed, purified to homogeneity and crystallized in a trigonal space group (P321 or P3(1)21/P3(2)21). The protein crystallized in two distinct trigonal crystal forms, with unit-cell parameters a = b = 111.0, c = 86.1 A and a = b = 111.0, c = 175.6 A, respectively. At a synchrotron beamline, the diffraction pattern extended to a resolution limit of 1.99 A. PMID:17012788

  5. Synthesis and structural and magnetic characterisation of cobalt(ii) complexes of mixed phosphonate-antimonate ligands.

    PubMed

    Ali, Shoaib; Muryn, Christopher A; Tuna, Floriana; Winpenny, Richard E P

    2010-10-28

    The polynucleating oxygen donor ligands, [(SbAr)(4)O(2)(PhPO(3)H)(4)(PhPO(3))(4)] 1 and [(SbAr)(2)O(HO(3)P(t)Bu)(6)] 2, based on condensation of p-chlorophenylstibonic acid (ArSbO(3)H(2)) and phosphonic acids, were used to prepare polymetallic cobalt(ii) complexes. Reaction of 1 with cobalt acetate under solvothermal conditions produces three different types of polymetallic cobalt complexes. With LiOMe/pyridine as base in MeOH a dinuclear cobalt cage, [Co(2)(SbAr)(4)O(4)(O(3)PPh)(4)(OMe)(4)py(2)] 3, is formed, with four Sb(ii) and two Co(ii) centres bridged by μ(3)-oxides and phosphonates. The pyridine in the structure can be replaced by 3-picoline 4, 4-picoline 5, quinoline 6, 1,2-diazole 7, 4-phenylpyridine 8, 4-ethyl pyridine 9 and methanol 10. Using pyrazine (pyz) instead of pyridine under the same conditions a polymer, [Co(2)(SbAr)(4)O(4)(O(3)PPh)(4)(OMe)(4)(C(4)H(4)N(2))](n)11, is formed. A similar 1D-polymer forms with 4,4'-bipyridyl-ethylene 12 in place of pyrazine. With Et(3)N/pyridine as base in MeCN a tetranuclear cobalt cage, [Co(4)(SbAr)(5)O(9)(O(3)PPh)(6)(py)(4)] 13, with five Sb(ii) centres forming a "bowtie" and bridging to four Co(ii) centres by phosphonates and μ(3)-oxides, is formed. The reaction of 2 with cobalt acetate using LiOMe/pyridine as base in methanol, under solvothermal conditions, produces a dinuclear Co(ii) complex, [Co(2)(SbAr)(2)(O(3)P(t)Bu)(3)O(2)(OMe)(2)(py)(2)] 14, with two Co(II) and two Sb centres at the vertices of a distorted tetrahedron. Magnetic measurements on selected number of these cobalt cages are reported.

  6. Atmospheric oxidation of fluorinated ethers, E143a (CF{sub 3}OCH{sub 3}), E134 (CHF{sub 2}OCHF{sub 2}), and E125 (CHF{sub 2}OCF{sub 3})

    SciTech Connect

    Good, D.A.; Kamboures, M.; Santiano, R.; Francisco, J.S.

    1999-11-18

    Because of the ability of chlorofluorocarbons (CFCs) to deplete stratospheric ozone, many applications have begun to employ hydrofluorocarbons (HFCs) as working fluids. HFCs contain no chlorine and are thus given ozone depletion potentials of essentially zero. Attention is now focused on global warming, with the goal of reducing greenhouse gas emissions. Air conditioners, heat pumps, and refrigeration devices that use refrigerants also use energy. They contribute to global warming both by the release of the refrigerant and by the emission of carbon dioxide and other greenhouse gases in powering the devices. The atmospheric oxidation mechanisms of E143a (CF{sub 3}OCH{sub 3}), E134 (CHF{sub 2}OCHF{sub 2}), and E125 (CHF{sub 2}OCF{sub 3}) have been investigated using experimental and ab initio methodology. The oxidation of E143a produces the stable reservoir species trifluoromethyl formate, CF{sub 3}OCOH, which further oxidizes to CF{sub 2}O and CO{sub 2}. Oxidation of E134 and E125 shows the presence of only CF{sub 2}O under the condition of high O{sub 2} concentrations. Carbonyl fluoride can be formed from two competing pathways involving the halogenated alkyl radicals formed from hydrogen abstraction of E134 and E125. CO bond fission reactions and O{sub 2} addition reactions compete to produce carbonyl fluoride and a CF{sub x}H{sub 3{minus}x} radical fragment. Computational modeling of the reaction pathways provides insight into the molecular steps of the degradation process.

  7. Structure of the puf operon of the obligately aerobic, bacteriochlorophyll alpha-containing bacterium Roseobacter denitrificans OCh114 and its expression in a Rhodobacter capsulatus puf puc deletion mutant.

    PubMed Central

    Kortlüke, C; Breese, K; Gad'on, N; Labahn, A; Drews, G

    1997-01-01

    Roseobacter denitrificans (Erythrobacter species strain OCh114) synthesizes bacteriochlorophyll a (BChl) and the photosynthetic apparatus only in the presence of oxygen and is unable to carry out primary photosynthetic reactions and to grow photosynthetically under anoxic conditions. The puf operon of R. denitrificans has the same five genes in the same order as in many photosynthetic bacteria, i.e., pufBALMC. PufC, the tetraheme subunit of the reaction center (RC), consists of 352 amino acids (Mr, 39,043); 20 and 34% of the total amino acids are identical to those of PufC of Chloroflexus aurantiacus and Rubrivivax gelatinosus, respectively. The N-terminal hydrophobic domain is probably responsible for anchoring the subunit in the membrane. Four heme-binding domains are homologous to those of PufC in several purple bacteria. Sequences similar to pufQ and pufX of Rhodobacter capsulatus were not detected on the chromosome of R. denitrificans. The puf operon of R. denitrificans was expressed in trans in Escherichia coli, and all gene products were synthesized. The Roseobacter puf operon was also expressed in R. capsulatus CK11, a puf puc double-deletion mutant. For the first time, an RC/light-harvesting complex I core complex was heterologously synthesized. The strongest expression of the R. denitrificans puf operon was observed under the control of the R. capsulatus puf promoter, in the presence of pufQ and pufX and in the absence of pufC. Charge recombination between the primary donor P+ and the primary ubiquinone Q(A)- was observed in the transconjugant, showing that the M and L subunits of the RC were correctly assembled. The transconjugants did not grow photosynthetically under anoxic conditions. PMID:9286973

  8. Electronic structure of the members of the electron transfer series [NiL](z) (z = 3+, 2+, 1+, 0) and [NiL(X)](n) (X = Cl, CO, P(OCH(3))(3)) species containing a tetradentate, redox-noninnocent, Schiff base macrocyclic ligand L: an experimental and density functional theoretical study.

    PubMed

    Ghosh, Meenakshi; Weyhermüller, Thomas; Wieghardt, Karl

    2010-02-28

    The electronic structure of the four members of the electron transfer series [NiL](z) (z = 3+, 2+, 1+, 0) have been established experimentally (EPR spectroscopy and X-ray crystallography) and by density functional theoretical (DFT) calculations using the B3LYP functional in conjunction with a conductor-like screening model (COSMO) for acetonitrile solvent effects. L represents a generic designation of the tetradentate macrocycle 2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]-heptadeca-1(17),2,11,13,15-pentane where the true oxidation level is not specified; (L(Ox))(0) represents its neutral form, (L )(1-) is the one-electron reduced pi radical anion, and (L(Red))(2-) is the singlet (or triplet) diradical dianion of this ligand. It is shown that the above series consists of square planar [Ni(III)(L(Ox))](3+) (S = 1/2), [Ni(II)(L(Ox))](2+) (S = 0), [Ni(II)(L )](1+) (S = 1/2), [Ni(II)(L(Red))](0) (S = 0). The structure of [Ni(II)(L(Red))](0) has been determined by X-ray crystallography. The electrochemistry of [Ni(II)(L(Ox))](PF(6))(2) in the presence of hard chloride anions shows the presence of trans-[Ni(III)(L(Ox))Cl(2)](+), the EPR spectrum of which has been recorded and calculated, and of trans-[Ni(II)(L(Ox))Cl(2)](0) (S = 1). Upon further reduction the coordinated Cl(-) ligands dissociate and [Ni(II)(L )](1+) and [Ni(II)(L(Red))](0) are successively generated. Similarly, in the presence of good pi-acceptor ligands such as CO or P(OCH(3))(3) the following five-coordinate, square base pyramidal species are found to be stable: [Ni(I)(L(Ox))(X)](1+) (S = 1/2), [Ni(I)(L )(X)](0) (S = 0, 1) (X = CO, P(OCH(3))(3)). As shown by EPR spectroscopy in the work of J. Lewis and M. Schröder, J. Chem. Soc., Dalton Trans., 1982, 1085, the monocations consist of a central nickel(i) ion (d(9), S(Ni) = 1/2). These spectra have been faithfully reproduced by the calculations. The neutral complexes [Ni(I)(L )(X)](0) are singlet or triplet diradicals comprising a central nickel

  9. Propulsion Velocity and ETT on Biomagnetic Assessment of the Human Esophagus

    SciTech Connect

    Cordova-Fraga, T.; Cano, E.; Bravo-Miranda, C.; De la Roca-Chiapas, J. M.; Bernal, J. J.; Sosa, M.; Huerta, R.

    2008-08-11

    Esophagus transit time measurement is a common clinical practical. Biomagnetic techniques and modern instrumentation can perform non invasive and functional assessments of the gastrointestinal tract. This study presents the evaluation of the esophagus transit time and propulsion velocity of a magnetic marker from the mouth to stomach using water vs. a swallow easy substance recently patented. A group of ten healthy subjects from 45 to 55 years, were evaluated in identical conditions for two times, they ingested randomly a magnetic marker in an anatomical body position of 45 deg., one times with water and the other one with a patented substance developed in order to help the subjects to swallow pills. The esophagus transit time was shorter when the subjects ingested the magnetic marker with the swallow easy substance than they ingested the magnetic marker with same quantity of water.

  10. Synthesis, characterization, structural and biological aspects of copper(II) dithiocarbamate complexes - Part II, [Cu{S2CN(Me)(R1)}2], [Cu{S2CN(Me)(R2)}2] and [Cu{S2CN(R3)(R4)}2] {R1 = CH2CH(OMe)2, R2 = 2-methyl-1,3-dioxolane, R3 = CH2(CH2)2NCHPhOCH2Ph and R4 = CH2CH2OH}

    NASA Astrophysics Data System (ADS)

    Ferreira, Isabella P.; de Lima, Geraldo M.; Paniago, Eucler B.; Takahashi, Jacqueline A.; Krambrock, Klaus; Pinheiro, Carlos B.; Wardell, James L.; Visentin, Lorenzo C.

    2013-09-01

    Three new copper(II) dithiocarbamates (DTC), [Cu{S2CN(Me)(R1)}2] (1), [Cu{S2CN(Me)(R2)}2] (2) and [Cu{S2CN(R3)(R4)}2] (3) with R1 = CH2CH(OMe)2, R2 = 2-methyl-1,3-dioxolane, R3 = CH2(CH2)2NCHPhOCH2Ph and R4 = CH2CH2OH, have been synthesized and characterized by different spectroscopic techniques. Complexes (1) and (2) display typical EPR spectra for separated Cu(II) centers, and the spectrum of (3) is characteristic of two magnetically coupled Cu(II) ions with S = 1. The X-ray crystallographic determination has shown that complexes (1) and (2) crystallise in the triclinic and monoclinic systems. In addition both complexes are monomers in which the geometry at each Cu(II) is square planar. The in vitro antimicrobial activity of the sodium salts of ligands, and of the Cu(II)-DTC complexes have been screened against Aspergillus flavus, Aspergillus niger, Aspergillus parasiticus, Penicillium citrinum and Curvularia senegalensis, as well as Gram positive and Gram negative bacteria. Finally, the toxic effects of complexes (1)-(3) were performed using Chlorella vulgaris.

  11. Sorption of aqueous antimony and arsenic species onto akaganeite.

    PubMed

    Kolbe, F; Weiss, H; Morgenstern, P; Wennrich, R; Lorenz, W; Schurk, K; Stanjek, H; Daus, B

    2011-05-15

    Two akaganeite materials were tested for the removal of antimonate, trimethyl antimonate, arsenate, arsenite, and dimethyl arsenate from water: a commercial product (GEH) and a synthesized akaganeite. The two materials show similar q(max) values, but differ in their K(L) values. This could be a result of their different crystal sizes indicated by sharper XRD reflections of the synthesized akaganeite compared with GEH. Batch experiments were carried out using all species to investigate the influence of the pH on their sorption onto the commercial material. The best results for the removal of antimonate and arsenate were achieved under acidic conditions, while the sorption of arsenite has an optimum at pH 7. The maximum loadings vary from 450 mg g(-1) (antimonate at pH 2.2.) to 2 mg g(-1) (trimethyl antimonate at pH 7). Competition reactions (up to a 10-fold excess of the competitor ion) were studied with antimonate, arsenate, and phosphate. The sorption capacity of arsenate decreases up to 12.5% by adding phosphate (ratio 1:10), but the addition of antimonate did not influence the sorption of arsenate. Conversely, the sorption of antimonate decreases due to the addition of 10-fold concentration of arsenate (31%) or phosphate (27%).

  12. Dagliga Separationer och Tidig Daghemsstart (Daily Separations and Early Entry into Day Care).

    ERIC Educational Resources Information Center

    Harsman, Ingrid

    The purpose of this thesis [Swedish language with English abstract and summary] was to study the reactions of infants when they started attending day care centers and to elucidate the process of adjustment. The theoretical perspective employed is the J. Bowlby/M. Ainsworth attachment theory. U. Bronfenbrenner's ecological theory of human…

  13. Aetervinning av faerg och ridaevatten med ultrafiltrering (recycling of paint and water curtains with ultrafiltration)

    SciTech Connect

    Fortkamp, U.; Allard, A.S.; Ekengren, O.

    1997-12-01

    Painting in spray booths causes overspray that is collected by a water curtain. The mixture of water and paint is commonly treated by means of precipitation. By means of this method, water can be used again but a paint sludge is created. Within this project, it was investigated how the paint as well as the water can be recycled. Separation by membrane filtration was tested for different paints in laboratory scale (0.2 liter volume). It was possible to separate all tested paints from the water and to concentrate it. At large scale (15 to 75 liters volume), an emulsion paint and a dispersion paint were tested. Under the tested conditions, it was slightly easier to concentrate the emulsion paint than the dispersion paint. It was possible to concentrate the paints to the original dry substance percentage. An important aspect of membrane filtration is cleaning of the membrane when the performance decreases. It was possible to clean all the tested membranes, but in many cases it was difficult. A ceramic membrane and a membrane of polyaramide showed the best results with regard to flux and cleaning of the membrane under the tested conditions. During the performance of the project two new applications of membrane filtration of paint were found. The method can be used for waste minimization by only separating the paint in an easy way at low costs. A third application is treating cleaning water from paint manufacturing.

  14. Sma Barn Pa Daghem: En studie av personalens samspel med barn och foraldrar vid lamning, hamtning och fri lek (Infants at Day Care: A Study of Staff Interaction with Children and Their Parents during Leaving, Collecting and Free Play).

    ERIC Educational Resources Information Center

    Lothigius, Anita Holmstedt

    This thesis presents a picture of how staff interact with infants (age group 1-3 years old) and parents at three day care centers. The study focused on the situations of leaving and collecting the children and the children's time of free play both in and outdoors. The theoretical content has an attachment/psycho-dynamical perspective with emphasis…

  15. Speciallararens Kunskaper Och Kompetens: Intervjuer med tio speciallarare (The Special Teacher's Knowledge and Competence: Interviews with Ten Special Teachers).

    ERIC Educational Resources Information Center

    Vernersson, Inga-Lill

    This thesis reports on a study in which 10 Swedish special education teachers were interviewed concerning the following six topics: (1) personal background and choice of a career; (2) professional knowledge; (3) the role of a special education teacher; (4) educational goals and methods; (5) cooperation; and (6) thoughts about the future.…

  16. Case study involving suctioning of an electromyographic endotracheal tube.

    PubMed

    Evanina, Eileen Youshock; Hanisak, Jill L

    2005-04-01

    The electromyographic endotracheal tube (EMG-ETT) is a relatively new tool used to measure integrity of the vocal cord structures during surgery. We describe a case in which an EMG-ETT was inserted for the operative period but not replaced with an ETT during the immediate postoperative period. Intensive care unit nurses had difficulty suctioning the EMG-ETT. The patient was not provided the pulmonary toilet necessary until the EMG-ETT was removed and replaced with a regular ETT. The purpose of this article is to make anesthesia providers aware that when mechanical ventilation is required during the postoperative period, the EMG-ETT should be removed and replaced with a regular ETT to facilitate pulmonary toilet. PMID:15835830

  17. Epithelioid Trophoblastic Tumor in a Postmenopausal Woman: A Case Report

    PubMed Central

    Park, Jung-Woo

    2016-01-01

    Epithelioid trophoblastic tumor (ETT) is a rare gestational trophoblastic neoplasm composed of intermediate trophoblasts. Most cases of ETT are reported in women of reproductive age following a prior gestation within 2 weeks to 30 years. ETT is extremely rare in postmenopausal women. It is commonly misdiagnosed as a poorly differentiated carcinoma or another type of gestational trophoblastic tumor. We report a case of ETT in a 56-year-old woman that developed 23 years after the patient's last pregnancy. PMID:27152314

  18. Ultrastructural localization of acid protein polysaccharides and calcium in the vacuoles of the chicken thrombocyte.

    PubMed

    Daimon, T; Uchida, K; Mizuhira, V

    1977-04-20

    The coexistence of acid protein polysaccharides and calcium in the vacuoles of chicken thrombocytes were studied by means of ultrahistochemical methods and electron probe X-ray microanalysis. The thrombocytes possessed large vacuoles of a surface connected membrane system. After both ruthenium red staining and tannic acid fixation the innersurface coat of vacuoles was always strongly and continously visualized. Electron microscopic X-ray microprobe analysis of antimonate precipitates in thrombocytes fixed in K-antimonate-OsO4 revealed calcium localization on the innersurface of vacuoles. From these facts it seems likely that the vacuoles of the surface connected membrane system may take part in the pool or the transport of calcium.

  19. Insights on the role of antimicrobial cuffed endotracheal tubes in preventing transtracheal transmission of VAP pathogens from an in vitro model of microaspiration and microbial proliferation.

    PubMed

    Rosenblatt, Joel; Reitzel, Ruth; Jiang, Ying; Hachem, Ray; Raad, Issam

    2014-01-01

    We developed an in vitro model to evaluate the effect of different cuffed endotracheal tubes (ETTs) on transtracheal transmission of ventilator-associated pneumonia (VAP) pathogens along external surfaces of ETTs. The model independently assessed the relative contributions of microbial proliferation to the distal tip and microaspiration of contaminated secretions past the cuff by testing in three modes: microaspiration only, microbial proliferation only, and simultaneous microaspiration and microbial proliferation. We evaluated transmission of methicillin resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa (PA) in the presence of a standard ETT; a soft, tapered cuff ETT with subglottic suctioning; and a novel antimicrobial gendine (combination of gentian violet and chlorhexidine) ETT in the model. In the microaspiration only mode, when leakage past the cuff occurred quickly, no ETT prevented transmission. When microaspiration was delayed, the gendine ETT was able to completely disinfect the fluid above the cuff and thereby prevent transmission of pathogens. In microbial proliferation only mode, the gendine ETT was the sole ETT that prevented transmission. With both mechanisms simultaneously available, transmission was dependent on how long microaspiration was delayed. Potent antimicrobial ETTs, such as a gendine ETT, can make unique contributions to prevent VAP when microaspiration is gradual.

  20. Rediscovering ancient glass technologies through the examination of opacifier crystals

    NASA Astrophysics Data System (ADS)

    Lahlil, S.; Biron, I.; Galoisy, L.; Morin, G.

    2008-07-01

    The aim of the study is to understand how antimonate opacifying crystals were obtained throughout history. Two archaeological glass productions opacified with calcium and lead antimonates are studied in this paper, in order to rediscover ancient opaque glass technologies: Roman mosaic tesserae (1st cent. B.C. 4th cent. A.D.) and Nevers lampworking glass (18th cent. A.D.). The fine examination of crystalline phases and of the vitreous matrix is undertaken using various and complementary techniques. Results are compared with a modern reference production, for which the technological process is well known. We demonstrate that Ca-antimonate opacifiers in Roman mosaic tesserae, as well as in Nevers lampworking glass, were obtained by in situ crystallization. Nevertheless, Roman and Nevers glass would have undergone different firing processes. We propose that the addition of previously synthesized crystals or the use of “anime” could be the process used to obtain Pb-antimonate opacified glass, for both productions studied. We demonstrate that CaO, PbO and Sb2O3 concentrations in the bulk compositions and in the matrices, and their evolution with the crystallinity ratio, offer robust criteria for the distinction of the opacification process used. Also, the different crystalline structures help to provide information on the experimental conditions.

  1. 40 CFR 421.146 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... § 421.146 Pretreatment standards for new sources. Except as provided in 40 CFR 403.7, any new source... 40 CFR part 403 and achieve the following pretreatment standards for new sources. The mass of... pounds) of antimony contained in sodium antimonate product Antimony 30.150 13.440 Arsenic 21.720...

  2. 40 CFR 421.146 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... § 421.146 Pretreatment standards for new sources. Except as provided in 40 CFR 403.7, any new source... 40 CFR part 403 and achieve the following pretreatment standards for new sources. The mass of... pounds) of antimony contained in sodium antimonate product Antimony 30.150 13.440 Arsenic 21.720...

  3. 40 CFR 421.146 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... § 421.146 Pretreatment standards for new sources. Except as provided in 40 CFR 403.7, any new source... 40 CFR part 403 and achieve the following pretreatment standards for new sources. The mass of... pounds) of antimony contained in sodium antimonate product Antimony 30.150 13.440 Arsenic 21.720...

  4. 40 CFR 421.146 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... § 421.146 Pretreatment standards for new sources. Except as provided in 40 CFR 403.7, any new source... 40 CFR part 403 and achieve the following pretreatment standards for new sources. The mass of... pounds) of antimony contained in sodium antimonate product Antimony 30.150 13.440 Arsenic 21.720...

  5. 40 CFR 421.146 - Pretreatment standards for new sources.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... § 421.146 Pretreatment standards for new sources. Except as provided in 40 CFR 403.7, any new source... 40 CFR part 403 and achieve the following pretreatment standards for new sources. The mass of... pounds) of antimony contained in sodium antimonate product Antimony 30.150 13.440 Arsenic 21.720...

  6. A multi-spectroscopic approach to the characterization of early glaze opacifiers: Studies on an Achaemenid glazed brick found at Susa, south-western Iran (mid-first millennium BC).

    PubMed

    Holakooei, Parviz

    2013-12-01

    This paper presents the results of micro-Raman spectroscopy, energy dispersive X-ray fluorescence (XRF), and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) studies performed on an Achaemenid glazed brick found at Susa (mid-first millennium BC). The results showed that calcium antimonate (CaSb2O6) and lead antimonate (Pb2Sb2O7) were used as white and yellow opacifiers in the white and orange glazes respectively. Moreover, the mixture of calcium antimonate and lead antimonate were used as opacifier in the green glaze. In addition, green, turquoise, blue, and orange colors were achieved by the dissolution of copper, cobalt, and iron-bearing materials in an alkali glaze. A black glazed line, whose color was obtained by copper and iron oxides, was used to separate the colored glazes. The present paper strongly suggests invasive micro-Raman spectroscopy for the identification of the opacifiers used in the early vitreous materials. PMID:23906671

  7. A multi-spectroscopic approach to the characterization of early glaze opacifiers: Studies on an Achaemenid glazed brick found at Susa, south-western Iran (mid-first millennium BC).

    PubMed

    Holakooei, Parviz

    2013-12-01

    This paper presents the results of micro-Raman spectroscopy, energy dispersive X-ray fluorescence (XRF), and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) studies performed on an Achaemenid glazed brick found at Susa (mid-first millennium BC). The results showed that calcium antimonate (CaSb2O6) and lead antimonate (Pb2Sb2O7) were used as white and yellow opacifiers in the white and orange glazes respectively. Moreover, the mixture of calcium antimonate and lead antimonate were used as opacifier in the green glaze. In addition, green, turquoise, blue, and orange colors were achieved by the dissolution of copper, cobalt, and iron-bearing materials in an alkali glaze. A black glazed line, whose color was obtained by copper and iron oxides, was used to separate the colored glazes. The present paper strongly suggests invasive micro-Raman spectroscopy for the identification of the opacifiers used in the early vitreous materials.

  8. A multi-spectroscopic approach to the characterization of early glaze opacifiers: Studies on an Achaemenid glazed brick found at Susa, south-western Iran (mid-first millennium BC)

    NASA Astrophysics Data System (ADS)

    Holakooei, Parviz

    2013-12-01

    This paper presents the results of micro-Raman spectroscopy, energy dispersive X-ray fluorescence (XRF), and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) studies performed on an Achaemenid glazed brick found at Susa (mid-first millennium BC). The results showed that calcium antimonate (CaSb2O6) and lead antimonate (Pb2Sb2O7) were used as white and yellow opacifiers in the white and orange glazes respectively. Moreover, the mixture of calcium antimonate and lead antimonate were used as opacifier in the green glaze. In addition, green, turquoise, blue, and orange colors were achieved by the dissolution of copper, cobalt, and iron-bearing materials in an alkali glaze. A black glazed line, whose color was obtained by copper and iron oxides, was used to separate the colored glazes. The present paper strongly suggests invasive micro-Raman spectroscopy for the identification of the opacifiers used in the early vitreous materials.

  9. Thermal conductivity of H2O-CH3OH mixtures at high pressures: Implications for the dynamics of icy super-Earths outer shells

    NASA Astrophysics Data System (ADS)

    Hsieh, Wen-Pin; Deschamps, Frédéric

    2015-10-01

    Thermal conductivity of H2O-volatile mixtures at extreme pressure-temperature conditions is a key factor to determine the heat flux and profile of the interior temperature in icy bodies. We use time domain thermoreflectance and stimulated Brillouin scattering combined with diamond anvil cells to study the thermal conductivity and sound velocity of water (H2O)-methanol (CH3OH) mixtures to pressures as high as 12 GPa. Compared to pure H2O, the presence of 5-20 wt % CH3OH significantly reduces the thermal conductivity and sound velocity when the mixture becomes ice VI-CH3OH and ice VII-CH3OH phases at high pressures, indicating that the heat transfer is hindered within the icy body. We then apply these results to model the heat transfer through the icy mantles of super-Earths, assuming that these mantles are animated by thermal convection. Our calculations indicate that the decrease of thermal conductivity due to the presence of 10 wt % CH3OH induces a twofold decrease of the power transported by convection.

  10. Att Tolka Barns Signaler: Gravt utvecklingsstorda flerhandikappade barns lek och kommunikation (To Interpret Childrens' Signals: Play and Communication in Profoundly Mentally Retarded and Multiply Handicapped Children).

    ERIC Educational Resources Information Center

    Brodin, Jane

    Written in Swedish with an English-language summary, this report describes a study which examined the interaction between mothers or caregivers and their children with profound mental retardation and multiple disabilities, particularly looking at the function of play in communicative interaction. The six children all had five or six handicaps in…

  11. Hydrogen isotope systematics among H2-H2O-CH4 during the growth of the hydrogenotrophic methanogen Methanothermobacter thermautotrophicus strain ΔH

    NASA Astrophysics Data System (ADS)

    Kawagucci, Shinsuke; Kobayashi, Mariko; Hattori, Shohei; Yamada, Keita; Ueno, Yuichiro; Takai, Ken; Yoshida, Naohiro

    2014-10-01

    Stable hydrogen isotope systematics among H2, H2O, and CH4 during hydrogenotrophic methanogenesis were investigated by growing a thermophilic methanogen, Methanothermobacter thermautotrophicus strain ΔH, in batch cultures spiked with deuterium-labeled H2 and/or H2O. The hydrogen isotope ratio of the product, CH4, reflected not only the isotope ratio of the H2O in the medium but also that of the substrate, H2. The D/H ratios of the CH4 were highest during the early phase of growth, and the growth-phase-dependent changes were greatest in the deuterium-enriched H2 cultures. The hydrogen isotope systematics among H2, H2O, and CH4 during growth of the methanogen could be described with the following equations: δDCH4=a×δDH2O+b×δDH2-c a=0.71-0.55×b 0.17⩽b⩽0.38 c=1000×(a+b-1) The greatest effect of δDH2 on δDCH4 (b = 0.38) was observed during the earliest phase of growth. In contrast to this study, the possible disappearance of the effect (b = 0) has been suggested in a previous study (Valentine et al., 2004a) in which Methanothermobacter marburgensis was cultured and hydrogen isotope systematics during growth was monitored, as was the case in this study. The close phylogenetic relationship between M. thermautotrophicus and M. marburgensis, which likely have similar biochemical pathways, suggests a possibly broad range of the b value, 0-0.38. To explain the observed hydrogen isotope systematics, two cellular mechanisms were proposed. One is that the hydrogen atoms of both H2 and H2O are directly incorporated into the product, CH4. The other is that all four hydrogen atoms in the product, CH4, are derived from intracellular H2O, which consists of a mixture of medium-derived pristine H2O and isotopically distinct H2O derived from methanogenic H2 oxidation. Although we attempted to evaluate the feasibility of these mechanisms, both cellular mechanisms remain hypothetical. The hydrogen isotope systematics shown here contribute to put forward utility of δDCH4 value as a geochemical tracer of the origins of environmental CH4.

  12. Investigation of Methanol Formation Mechanisms in H2O+CH4 Ices Subjected to 5 keV Electrons at a 10-100 K Temperature Range

    NASA Astrophysics Data System (ADS)

    Stelmach, K. B.; Cooper, P. D.

    2014-12-01

    Methane (CH4) and water are one of the most common molecules in both planetary bodies and interstellar dust grains. Another common molecule, methanol (CH3OH), is thought to form in CH4+H2O ices. However, the exact formation mechanisms of methanol from cosmic rays are not well known, especially in the temperatures of interest. Experiments were performed using high energy electrons (5 keV) to irradiate mixtures of 1:10, 1:5, and 1:3 CH4+H2O ices under a temperature range of 10-100 Kelvin with Fourier Transform Infrared (FTIR) spectroscopy being used to identify the products. Isotopologues of the two molecules (D2O and CD4) were used to probe for the mechanisms. Other products were formed as well and their potential mechanisms are identified. The implications of the mechanisms for planetary and interstellar chemistry are discussed.

  13. Evidence-based guideline for suctioning the intubated neonate and infant.

    PubMed

    Gardner, Denice L; Shirland, Lee

    2009-01-01

    The endotracheal tube (ETT) is the most common artificial airway used in NICUs. Suctioning of the ETT is imperative to maintain patency and prevent complications. An extensive review of the literature revealed a lack of standardized criteria or guidelines for suctioning the ETT of neonates and infants in the NICU. The purpose of this article is to report the implementation of an evidence-based guideline that can be utilized in NICU care.

  14. Differentiation of stem cells into insulin-producing cells under the influence of nanostructural polyoxometalates.

    PubMed

    Bâlici, Ştefana; Şuşman, Sergiu; Rusu, Dan; Nicula, Gheorghe Zsolt; Soriţău, Olga; Rusu, Mariana; Biris, Alexandru S; Matei, Horea

    2016-03-01

    Two polyoxometalates (POMs) with W were synthesized by a two-step, self-assembling method. They were used for stimulation of mesenchymal stem cell differentiation into insulin-producing cells. The nanocompounds (tris(vanadyl)-substituted tungsto-antimonate(III) anions [POM1] and tris-butyltin-21-tungsto-9-antimonate(III) anions [POM2]) were characterized by analytical techniques, including ultraviolet-visible, Fourier transform infrared, nuclear magnetic resonance spectroscopy, and transmission electron microscopy. We found that these polyoxotungstates, with 2-4 nm diameters, did not present toxic effects at the tested concentrations. In vitro, POM1 stimulated differentiation of a greater number of dithizone-positive cells (also organized in clusters) than the second nanocompound (POM2). Based on our in vitro studies, we have concluded that both the POMs tested had significant biological activity acting as active stimuli for differentiation of stem cells into insulin-producing cells. PMID:26397720

  15. Test procedure for cation exchange chromatography

    SciTech Connect

    Cooper, T.D.

    1994-08-24

    The purpose of this test plan is to demonstrate the synthesis of inorganic antimonate ion exchangers and compare their performance against the standard organic cation exchangers. Of particular interest is the degradation rate of both inorganic and organic cation exchangers. This degradation rate will be tracked by determining the ion exchange capacity and thermal stability as a function of time, radiation dose, and chemical reaction.

  16. 40 CFR 421.142 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... available. Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this... contained in sodium antimonate product Antimony 44.840 20.000 Arsenic 32.650 14.530 Mercury 3.906 1.562... produced by electrowinning Antimony 44.840 20.000 Arsenic 32.650 14.530 Mercury 3.906 1.562 Total...

  17. 40 CFR 421.143 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart shall achieve... sodium antimonate product Antimony 30.150 13.440 Arsenic 21.720 9.687 Mercury 2.344 0.937 (b) Fouled... electrowinning Antimony 30.150 13.440 Arsenic 21.720 9.687 Mercury 2.344 0.937 (c) Cathode Antimony Wash...

  18. 40 CFR 421.143 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart shall achieve... sodium antimonate product Antimony 30.150 13.440 Arsenic 21.720 9.687 Mercury 2.344 0.937 (b) Fouled... electrowinning Antimony 30.150 13.440 Arsenic 21.720 9.687 Mercury 2.344 0.937 (c) Cathode Antimony Wash...

  19. 40 CFR 421.143 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart shall achieve... sodium antimonate product Antimony 30.150 13.440 Arsenic 21.720 9.687 Mercury 2.344 0.937 (b) Fouled... electrowinning Antimony 30.150 13.440 Arsenic 21.720 9.687 Mercury 2.344 0.937 (c) Cathode Antimony Wash...

  20. 40 CFR 421.142 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... available. Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this... contained in sodium antimonate product Antimony 44.840 20.000 Arsenic 32.650 14.530 Mercury 3.906 1.562... produced by electrowinning Antimony 44.840 20.000 Arsenic 32.650 14.530 Mercury 3.906 1.562 Total...

  1. 40 CFR 421.142 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... available. Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this... contained in sodium antimonate product Antimony 44.840 20.000 Arsenic 32.650 14.530 Mercury 3.906 1.562... produced by electrowinning Antimony 44.840 20.000 Arsenic 32.650 14.530 Mercury 3.906 1.562 Total...

  2. 40 CFR 421.142 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... available. Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this... contained in sodium antimonate product Antimony 44.840 20.000 Arsenic 32.650 14.530 Mercury 3.906 1.562... produced by electrowinning Antimony 44.840 20.000 Arsenic 32.650 14.530 Mercury 3.906 1.562 Total...

  3. 40 CFR 421.143 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart shall achieve... sodium antimonate product Antimony 30.150 13.440 Arsenic 21.720 9.687 Mercury 2.344 0.937 (b) Fouled... electrowinning Antimony 30.150 13.440 Arsenic 21.720 9.687 Mercury 2.344 0.937 (c) Cathode Antimony Wash...

  4. 40 CFR 421.143 - Effluent limitations guidelines representing the degree of effluent reduction attainable by the...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart shall achieve... sodium antimonate product Antimony 30.150 13.440 Arsenic 21.720 9.687 Mercury 2.344 0.937 (b) Fouled... electrowinning Antimony 30.150 13.440 Arsenic 21.720 9.687 Mercury 2.344 0.937 (c) Cathode Antimony Wash...

  5. Negative tracheal pressure during neonatal endotracheal suction.

    PubMed

    Kiraly, Nicholas J; Tingay, David G; Mills, John F; Morley, Colin J; Copnell, Beverley

    2008-07-01

    Endotracheal tube (ETT) suction is the most frequently performed invasive procedure in ventilated newborn infants and is associated with adverse effects related to negative tracheal pressure. We aimed to measure suction catheter gas flow and intratracheal pressure during ETT suction of a test lung and develop a mathematical model to predict tracheal pressure from catheter and ETT dimensions and applied pressure. Tracheal pressure and catheter flow were recorded during suction of ETT sizes 2.5-4.0 mm connected to a test lung with catheters 5-8 French Gauge and applied pressures of 80-200 mm Hg. The fraction of applied pressure transmitted to the trachea was calculated for each combination, and data fitted to three nonlinear models for analysis. Tracheal pressure was directly proportional to applied pressure (r = 0.82-0.99), and catheter flow fitted a turbulent flow model (R = 0.85-0.96). With each ETT, increasing catheter size resulted in greater catheter flow (p < 0.0001) and thus lower intratracheal pressure (p < 0.0001). The fraction of applied pressure transmitted to the trachea was accurately modeled using ETT and catheter dimensions (R = 0.98-0.99). Negative tracheal pressure during in vitro ETT suction is directly proportional to applied pressure. This relationship is determined by ETT and catheter dimensions.

  6. Children's Implicit Learning of Graphotactic and Morphological Regularities

    ERIC Educational Resources Information Center

    Pacton, Sbastien; Fayol, Michel; Perruchet, Pierre

    2005-01-01

    In French, the transcription of the same sound can be guided by both probabilistic graphotactic constraints (e.g., t is more often transcribed ette after -v than after -f) and morphological constraints (e.g., t is always transcribed ette when used as a diminutive suffix). Three experiments showed that pseudo-word spellings of 8-to 11-year-old…

  7. [BLOODSUCKING MOSQUITOES (DIPTERA: CULICIDAE) IN, THE TULA REGION ARE POTENTIAL VECTORS OF DIROFILARIAS].

    PubMed

    Bogacheva, A S; Ganushkina, L A; Lopatina, Yu V

    2015-01-01

    Bloodsucking mosquitoes were collected in Tula and its Region in May to August 2013-2014. The fauna included 17 species from 5 genera in the subfamily Culicinae and Anopheles maculipennis complex in the subsystem Anophelinae. Ochlerotatus cantans was a dominant species in the collections. The dominant species also included Aedes einereus, Ae. vexans, Ae. geniculatus, Och. diantaeus, Och. intrudens, Och. Cataphylla, and Culex pipiens. The possible value of different mosquito species Dirofilaria repens and D. immitis as vectors of dirofilarasis was discussed.

  8. Synthesis and evaluation of κ(2)-β-diketonate and β-ketoesterate tungsten(vi) oxo-alkoxide complexes as precursors for chemical vapor deposition of WOx thin films.

    PubMed

    Bonsu, Richard O; Bock, Duane C; Kim, Hankook; Korotkov, Roman Y; Abboud, Khalil A; Anderson, Timothy J; McElwee-White, Lisa

    2016-07-01

    Reactions of [WO(OR)4]x (x = 1, 2) complexes with bidentate ligands (LH = acacH, tbacH, dpmH, tbpaH) afforded complexes : [WO(OCH3)3(acac) (); WO(OCH2CH3)3(acac) (); WO(OCH(CH3)2)3(acac) (); WO(OCH3)3(tbac) (); WO(OCH2CH3)3(tbac) (); WO(OCH(CH3)2)3(tbac) (); WO(OCH2CH3)3(dpm) (); WO(OCH(CH3)2)3(dpm) (); WO(OCH2C(CH3)3)3(acac) (); WO(OCH2C(CH3)3)3(tbac) (); WO(OCH2C(CH3)3)3(dpm) (); WO(OCH2C(CH3)3)3(tbpa) (); WO(OC(CH3)3)3(tbac) ()]. The synthesis is facilitated by the lability of the bridging ligands of the [WO(OR)4]2 complexes in solution, which provides a pathway for exchange of L with an alkoxide ligand. Thermogravimetric analysis and the conditions for sublimation or distillation of demonstrate that they have sufficient vapor pressure and thermal stability for volatilization in a conventional Chemical Vapor Deposition (CVD) reactor. High solubility in hydrocarbon and ether solvents establishes that the complexes are also potential candidates for Aerosol-Assisted Chemical Vapor Deposition (AACVD). AACVD from on ITO or bare glass resulted in growth of continuous, dense and amorphous thin films of substoichiometric WOx between 250-350 °C and nanorods of W18O49 above 350 °C. PMID:27160734

  9. Treatment of air pollution control residues with iron rich waste sulfuric acid: does it work for antimony (Sb)?

    PubMed

    Okkenhaug, Gudny; Breedveld, Gijs D; Kirkeng, Terje; Lægreid, Marit; Mæhlum, Trond; Mulder, Jan

    2013-03-15

    Antimony (Sb) in air pollution control (APC) residues from municipal solid waste incineration has gained increased focus due to strict Sb leaching limits set by the EU landfill directive. Here we study the chemical speciation and solubility of Sb at the APC treatment facility NOAH Langøya (Norway), where iron (Fe)-rich sulfuric acid (∼3.6M, 2.3% Fe(II)), a waste product from the industrial extraction of ilmenite, is used for neutralization. Antimony in water extracts of untreated APC residues occurred exclusively as pentavalent antimonate, even at low pH and Eh values. The Sb solubility increased substantially at pH<10, possibly due to the dissolution of ettringite (at alkaline pH) or calcium (Ca)-antimonate. Treated APC residues, stored anoxically in the laboratory, simulating the conditions at the NOAH Langøya landfill, gave rise to decreasing concentrations of Sb in porewater, occurring exclusively as Sb(V). Concentrations of Sb decreased from 87-918μgL(-1) (day 3) to 18-69μgL(-1) (day 600). We hypothesize that an initial sorption of Sb to Fe(II)-Fe(III) hydroxides (green rust) and eventually precipitation of Ca- and Fe-antimonates (tripuhyite; FeSbO4) occurred. We conclude that Fe-rich, sulfuric acid waste is efficient to immobilize Sb in APC residues from waste incineration. PMID:23465722

  10. Alkali oxide-tantalum, niobium and antimony oxide ionic conductors

    NASA Technical Reports Server (NTRS)

    Roth, R. S.; Brower, W. S.; Parker, H. S.; Minor, D. B.; Waring, J. L.

    1975-01-01

    The phase equilibrium relations of four systems were investigated in detail. These consisted of sodium and potassium antimonates with antimony oxide and tantalum and niobium oxide with rubidium oxide as far as the ratio 4Rb2O:llB2O5 (B=Nb, Ta). The ternary system NaSbO3-Sb2O4-NaF was investigated extensively to determine the actual composition of the body centered cubic sodium antimonate. Various other binary and ternary oxide systems involving alkali oxides were examined in lesser detail. The phases synthesized were screened by ion exchange methods to determine mobility of the mobility of the alkali ion within the niobium, tantalum or antimony oxide (fluoride) structural framework. Five structure types warranted further investigation; these structure types are (1) hexagonal tungsten bronze (HTB), (2) pyrochlore, (3) the hybrid HTB-pyrochlore hexagonal ordered phases, (4) body centered cubic antimonates and (5) 2K2O:3Nb2O5. Although all of these phases exhibit good ion exchange properties only the pyrochlore was prepared with Na(+) ions as an equilibrium phase and as a low porosity ceramic. Sb(+3) in the channel interferes with ionic conductivity in this case, although relatively good ionic conductivity was found for the metastable Na(+) ion exchanged analogs of RbTa2O5F and KTaWO6 pyrochlore phases.

  11. Cytochemical localization of calcium in soybean root cap cells in microgravity.

    PubMed

    Klymchuk, D O; Brown, C S; Chapman, D K; Vorobyova, T V; Martyn, G M

    2001-01-01

    The antimonate precipitation technique was used to evaluate the effects of microgravity and ethylene on the cellular and subcellular distribution of free calcium ions in soybean root apices. Soybean (Glycine max L. [Merr.]) dry seeds were launched, activated by hydration, and germinated in the presence of KMnO4 (to remove ethylene) and in its absence onboard the space shuttle Columbia during the STS-87 mission. Primary root apices of 6-day old seedlings were fixed for electron microscopy after landing. Ultrastructural studies indicated that antimonate precipitation appeared as individual electron-dense particles which were more or less round in shape and varied in diameter from 10 nm (minimum size beginning from which the particles were well identified) to 90 nm. It was revealed that analyzed root cap cells varied in both the precipitate particle sizes and the amount particles per unit of the cellular area. In both flight and ground control treatments, antimonate precipitation level increases from apical meristem cells to peripheral (secretory) cells of root apices. In root cap statocytes, subcellular localization of precipitate particles was revealed in the cytoplasm, nucleus and small vacuoles. The quantitative analysis showed a reduction of precipitate density in the cytoplasm and the nucleus, and an increase in precipitate density in the vacuoles from statocytes of both spaceflight treatments in comparison with ground controls.

  12. [Final report for DOE contract FG03-88ER13882

    SciTech Connect

    1999-04-30

    The female reproductive organ, the gynoecium, is the most complex structure that plants produce. The molecular mechanisms that coordinate its development are unknown, but can be dissected by molecular genetics. The ettin (ett) mutation provides a remarkable window for viewing gynoecium development. ett induced alterations result from misinterpretation of positional information along longitudinal and transverse gynoecial axes. Molecular cloning revealed the ETT encoded amino acid sequence is homologous to transcriptional factors involved in signaling by the plant hormone auxin. Early ETT gene expression marks the site of the future outgrowth of the gynoecium. The primary gene sequence and pattern of expression of ETT fits with a role in hormone mediated signaling for regional development in the female organ.

  13. Removal of endotracheal tube obstruction with a secretion clearance device.

    PubMed

    Mietto, Cristina; Foley, Kevin; Salerno, Lindsay; Oleksak, Jenna; Pinciroli, Riccardo; Goverman, Jeremy; Berra, Lorenzo

    2014-09-01

    Accumulation of secretions may suddenly occlude an endotracheal tube (ETT), requiring immediate medical attention. The endOclear catheter (Endoclear LLC, Petoskey, Michigan) is a novel device designed to clear mucus and debris from an ETT and restore luminal patency. We present 3 subsequent cases of life-threatening partial ETT occlusions recorded over a period of 6 months at Massachusetts General Hospital. After conventional methods (standard tracheal suctioning and bronchoscopy) failed, the endOclear was used, with successful restoration of the airways in all 3 cases. The respiratory conditions rapidly improved, and all 3 patients tolerated the ETT-cleaning maneuver. These results show that such a device is safe and easy to use during an emergency airway situation for efficient and rapid removal of secretions from obstructed ETTs by respiratory therapists.

  14. Additional work of breathing imposed by endotracheal tubes, breathing circuits, and intensive care ventilators.

    PubMed

    Bersten, A D; Rutten, A J; Vedig, A E; Skowronski, G A

    1989-07-01

    A disadvantage of spontaneous breathing through an endotracheal tube (ETT) and connector attached to a breathing circuit and/or ventilator (breathing device) is an increase in the work of breathing. The work of breathing associated with ETT of 6 to 9-mm diameter and eight breathing devices was determined, using a lung simulator to mimic spontaneous inspiration at flow rates of 20 to 100 L/min and a tidal volume of 500 ml, at both zero end-expiratory pressure (ZEEP) and 10 cm H2O continuous positive airway pressure (CPAP). Work associated with the breathing devices alone (WCIR) ranged from -0.002 kg.m/L (Servo 900-C ventilator, 7-mm ETT, 20 L/min, ZEEP) to 0.1 kg.m/L (continuous flow circuit, 7-mm ETT, 100 L/min, CPAP), the latter representing 196% of the work of normal breathing. When the devices were attached to ETT, total apparatus work (WAPP) ranged from 0.009 kg.m/L (Mapleson-D circuit, 9-mm ETT, 20 L/min, ZEEP) to 0.25 kg.m/L (Drager EV-A, 6-mm ETT, 100 L/min, ZEEP), the latter representing 490% of the work of normal breathing. This additional work imposed by the ETT varied considerably among devices. Spontaneous breathing through modern ventilators, circuits and ETT imposes a burden of increased work, most of which is associated with the presence of the ETT and connector. Whether this burden represents an impediment to the weaning patient, or has training value for the ultimate resumption of unassisted spontaneous ventilation, remains to be determined.

  15. ETTIN (ARF3) physically interacts with KANADI proteins to form a functional complex essential for integument development and polarity determination in Arabidopsis.

    PubMed

    Kelley, Dior R; Arreola, Alexandra; Gallagher, Thomas L; Gasser, Charles S

    2012-03-01

    KANADI (KAN) transcription factors promote abaxial cell fate throughout plant development and are required for organ formation during embryo, leaf, carpel and ovule development. ABERRANT TESTA SHAPE (ATS, or KAN4) is necessary during ovule development to maintain the boundary between the two ovule integuments and to promote inner integument growth. Yeast two-hybrid assays identified ETTIN (ETT, or AUXIN RESPONSE FACTOR 3) as a transcription factor that could physically interact with ATS. ATS and ETT were shown to physically interact in vivo in transiently transformed tobacco epidermal cells using bimolecular fluorescence complementation. ATS and ETT were found to share an overlapping expression pattern during Arabidopsis ovule development and loss of either gene resulted in congenital fusion of the integuments and altered seed morphology. We hypothesize that in wild-type ovules a physical interaction between ATS and ETT allows these proteins to act in concert to define the boundary between integument primordia. We further show protein-protein interaction in yeast between ETT and KAN1, a paralog of ATS. Thus, a direct physical association between ETT and KAN proteins underpins their previously described common role in polarity establishment and organogenesis. We propose that ETT-KAN protein complex(es) constitute part of an auxin-dependent regulatory module that plays a conserved role in a variety of developmental contexts. PMID:22296848

  16. Self-assembled nanoparticles based on hydrophobically modified chitosan as carriers for doxorubicin.

    PubMed

    Zhang, Jing; Chen, Xi Guang; Li, Yan Yan; Liu, Cheng Sheng

    2007-12-01

    In this study self-assembled nanoparticles based on oleoyl-chitosan (OCH) were prepared with a mean diameter of 255.3 nm and an almost spherical shape. The toxicity profile of OCH nanoparticles was evaluated in vitro via hemolysis test and MTT assay. The hemolysis rates of OCH nanoparticles tested in different conditions came well within permissible limits (5%). The OCH nanoparticles showed no cytotoxicity to mouse embryo fibroblasts. Doxorubicin (DOX) was efficiently loaded into OCH nanoparticles with an encapsulation efficiency of 52.6%. The drug was rapidly and completely released from the nanoparticles (DOX-OCH nanoparticles) at pH 3.8, whereas at pH 7.4 there was a sustained release after a burst release. The inhibitory rates of DOX-OCH nanoparticle suspension to different human cancer cells (A549, Bel-7402, HeLa, and SGC-7901) significantly outperformed that of DOX solution. These results revealed the potential of OCH nanoparticles as carriers for hydrophobic antitumor agents.

  17. ORGANONICKEL CHEMISTRY IN THE CATALYTIC HYDRODECHLORINATION OF POLYCHLOROBIPHENYLS (PCBS): LIGAND STERIC EFFECTS AND MOLECULAR STRUCTURE OF REACTION INTERMEDIATES. (R823526)

    EPA Science Inventory

    Abstract

    Soluble homogeneous organophosphorus¯¯nickel complexes have been used to detoxify polychlorinated biphenyls (PCBs) by catalyzed hydrodechlorination using NaBH2(OCH2CH2OCH3)2 as the hyd...

  18. Discourse Markers in Chinese Conversational Narrative

    ERIC Educational Resources Information Center

    Xiao, Yang

    2010-01-01

    This study examines the indexicality of discourse markers (DMs) in Chinese conversational narrative. Drawing upon theoretical and methodological principles related to narrative dimensions (Ochs & Capps, 2001), narrative desires (Ochs, 1997, 2004), and narrative positioning (Bamberg, 1997), this work proposes an integrated analytical framework for…

  19. Ecological Functions of Off-Channel Habitats of the Willamette River, Oregon, Database and Documentation (1997-2001)

    EPA Science Inventory

    The database from the Ecological Functions of Off-Channel Habitats of the Willamette River, Oregon project (OCH Project) contains data collected from 1997 through 2001 from multiple research areas of the project, and project documents such as the OCH Research Plan, Quality Assura...

  20. Lysophosphatidylcholine attenuates the cytotoxic effects of the antineoplastic phospholipid 1-O-octadecyl-2-O-methyl-rac-glycero-3- phosphocholine.

    PubMed

    Boggs, K P; Rock, C O; Jackowski, S

    1995-05-12

    A colony-stimulating factor 1-dependent cell line was used to determine the relationship between the inhibition of phospholipid synthesis and the cytotoxic activity of the antineoplastic ether lipid, 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3). ET-18-OCH3 inhibited choline incorporation into phosphatidylcholine as well as total phospholipid synthesis. Exposure to ET-18-OCH3 at the G1/S boundary led to the accumulation of cells in G2, whereas the addition of ET-18-OCH3 in the G1 phase of the cell cycle prevented entry into the S phase. In both cases, ET-18-OCH3 treatment triggered DNA fragmentation and morphological changes associated with apoptosis within 10 h. The addition of lysophosphatidylcholine provided an exogenous source of cellular phospholipid and prevented ET-18-OCH3-dependent accumulation of cells in G2 and apoptosis. However, lysophosphatidylcholine did not overcome the ET-18-OCH3-dependent G1 block, although the growth-arrested cells remained viable. These data indicate that restoring phosphatidylcholine synthesis by supplementation with lysophosphatidylcholine overrides the cytotoxic but not the cytostatic activity of ET-18-OCH3.

  1. Eletriptan metabolism by human hepatic CYP450 enzymes and transport by human P-glycoprotein.

    PubMed

    Evans, David C; O'Connor, Desmond; Lake, Brian G; Evers, Raymond; Allen, Christopher; Hargreaves, Richard

    2003-07-01

    "Reaction phenotyping" studies were performed with eletriptan (ETT) to determine its propensity to interact with coadministered medications. Its ability to serve as a substrate for human P-glycoprotein (P-gp) was also investigated since a central mechanism of action has been proposed for this "triptan" class of drug. In studies with a characterized bank of human liver microsome preparations, a good correlation (r2 = 0.932) was obtained between formation of N-desmethyl eletriptan (DETT) and CYP3A4-catalyzed testosterone 6 beta-hydroxylation. DETT was selected to be monitored in our studies since it represents a significant ETT metabolite in humans, circulating at concentrations 10 to 20% of those observed for parent drug. ETT was metabolized to DETT by recombinant CYP2D6 (rCYP2D6) and rCYP3A4, and to a lesser extent by rCYP2C9 and rCYP2C19. The metabolism of ETT to DETT in human liver microsomes was markedly inhibited by troleandomycin, erythromycin, miconazole, and an inhibitory antibody to CYP3A4, but not by inhibitors of other major P450 enzymes. ETT had little inhibitory effect on any of the P450 enzymes investigated. ETT was determined to be a good substrate for human P-gp in vitro. In bidirectional transport studies across LLC-MDR1 and LLC-Mdr1a cell monolayers, ETT had a BA/AB transport ratio in the range 9 to 11. This finding had significance in vivo since brain exposure to ETT was reduced 40-fold in Mdr1a+/+ relative to Mdr1a-/- mice. ETT metabolism to DETT is therefore catalyzed primarily by CYP3A4, and plasma concentrations are expected to be increased when coadministered with inhibitors of CYP3A4 and P-gp activity. PMID:12814962

  2. Inadvertent migration of guidewire into Murphy's eye of endotracheal tube during percutaneous dilatational tracheostomy

    PubMed Central

    Panigrahi, Binita; Samaddar, Devi Prasad; Kumar, Tushar

    2016-01-01

    Percutaneous dilatational tracheostomy is a commonly performed bedside procedure in the Intensive Care Unit. Although serious and fatal complications have been reported, the procedure is by and large safe to perform in experienced hands. We report here an innocuous problem encountered twice. After the guidewire insertion and dilatation, subsequent railroading became difficult owing to migration of guidewire into the Murphy's eye of the endotracheal tube (ETT). Awareness about this possibility can avert inadvertent delays and complications during the procedure. A tug or gentle pulling of ETT after insertion of the guidewire rules out an impaction in the eye or other part of the ETT. PMID:27076734

  3. Discordance of exercise thallium testing with coronary arteriography in patients with atypical presentations

    SciTech Connect

    Bungo, M.W.; Leland, O.S. Jr.

    1983-01-01

    Eighty-one patients with diagnostically difficult clinical presentations suggesting coronary disease underwent symptom-limited maximal-exercise treadmill testing (ETT) and exercise radionuclide scanning with /sup 201/Tl. Results of these tests were in agreement in only 47 percent of the cases. Either exercise thallium or ETT was positive in 94 percent of patients with disease. Among a population with a disease prevalence of 67 percent, agreement between exercise thallium an ETT predicted disease in 92 percent of instances or excluded disease in 82 percent of instances. Frequent discordance between these two tests in 53 percent of the cases unfortunately limits this usefulness.

  4. Hybrid SPECT/CT evaluation of dual ectopia of thyroid in the absence of orthotopic thyroid gland.

    PubMed

    Harisankar, Chidambaram Natrajan Balasubramanian; Preethi, Govindababu Rajalakshmi; George, Mv

    2012-06-01

    Ectopic thyroid tissue (ETT) refers to all cases in which the thyroid gland is present at a location other than its usual site. The prevalence of ETT is approximately 1 per 100,000 to 300,000 persons and is reported to occur in 1 of 4000 to 8000 patients with thyroid disease. Multiple ectopia of the thyroid is extremely rare, with fewer than 35 cases published in literature to date. We report a 4-year-old girl with euthyroid and dual ectopia of thyroid without orthotopic thyroid gland. The role of hybrid SPECT/CT in the localization of the sites of ETT is also highlighted. PMID:22614198

  5. Strength investigation of artificial substitutes for human teeth in in vitro studies.

    PubMed

    Rosentritt, Martin; Reill, Margarete; Naumann, Michael; Nowak, Arnold; Handel, Gerhard

    2009-01-01

    This study investigated whether metals or resins can replace human teeth in in vitro fracture tests of endodontically treated teeth (ETT), as ETT show high heterogeneity and small availability. Eight incisor-shaped roots per group were adhesively restored with fiber-reinforced composite posts, composite core build-ups and Co-Cr-Mo crowns. Specimens were thermally cycled and mechanically loaded (TCML) and fracture strength was determined. The results varied between 0 N and 348 N. Extracted ETT may show comparable strength and survival during TCML to teeth in situ and therefore are the first choice for in vitro testing. Substitutes show comparable fracture patterns but different fracture values. PMID:19260430

  6. Fluid inclusions in the system H sub 2 O-CH sub 4 -NaCl-CO sub 2 from metasomatic tourmaline within the border unit of the Tanco zoned granitic pegmatite, S. E. Manitoba

    SciTech Connect

    Thomas, A.V.; Spooner, E.T. )

    1988-05-01

    Fluid inclusions from the tourmaline phase of alteration of the footwall amphibolite from the Tanco zoned granitic pegmatite lie in the system H{sub 2}O-CH{sub 4}-NaCl-CO{sub 2}. These inclusions contain a liquid and vapor phase at room temperature and develop a second liquid phase on cooling in the range {minus}77 to {minus}95{degree}C: the second liquid and the vapor are methane. Isochores for inclusions showing vapor phase (CH{sub 4}) homogenization were constructed from the equations of Jacobs and Kerrick (1981). The intersections of these isochores with the univariant melting curves for methane clathrate hydrates give estimates of salinity for the inclusions of between 7 and 10 equivalent wt.% NaCl, which are lower than those derived from measurement of the depression of the melting point of ice; a result consistent with salt exclusion by clathrate. The bulk composition of the fluid is estimated to be 91 mol.% H{sub 2}O, 6 mol.% CH{sub 4}, 2 equiv. mol.% NaCl and <1 mol.% CO{sub 2}. Total homogenization temperatures have a mean value of 371{degree}C {plus minus} 36{degree}C. Calculation of f{sub O2} from the bulk inclusion composition gives values near WI at these conditions which is unreasonably low for fluids derived from the pegmatite, which were probably between QFM and HM. The metasomatic fluids may have resulted from fluid mixing in the wall rock immediately adjacent to the pegmatite. The fluid derived from the pegmatite, a H{sub 2}O-CO{sub 2} fluid, introduced the B necessary to form tourmaline in the amphibolite. Supporting evidence is provided by pegmatite wall zone fluids with higher CH{sub 4} than the bulk of the pegmatite H{sub 2}O-CO{sub 2} fluids, suggesting marginal fluid contamination.

  7. Larande I Produktionssytem. En studie av operatorsarbete i hogautomatiserad process--och verkstadsindustri = Learning in Production Systems. A Study of Operator Work in Highly Automated Process and Manufacturing Industry. Linkoping Studies in Education and Psychology, No. 63.

    ERIC Educational Resources Information Center

    Davidson, Bo; Svedin, Per-Olof

    This study of the conditions of developmental on-the-job training and learning for operators in highly automated industries is written in Swedish but contains an English abstract and 18-page summary. The summary begins with the study objectives, which were to determine the following: (1) conditions of developmental on-the-job learning in highly…

  8. Effects of oligochitosan on postharvest Alternaria rot, storage quality, and defense responses in Chinese jujube (Zizyphus jujuba Mill. cv. Dongzao) fruit.

    PubMed

    Yan, Jiaqi; Li, Jian; Zhao, Hongwei; Chen, Ni; Cao, Jiankang; Jiang, Weibo

    2011-05-01

    Effects of oligochitosan (OCH) on postharvest rot caused by Alternaria alternata in Chinese jujube (Zizyphus jujuba Mill. cv. Dongzao) fruit were investigated. An in vitro test indicated that mycelial growth of A. alternata was strongly suppressed by OCH at 0.5, 1, 2, 5, 10, 15, or 20 g/liter. The half-inhibition concentration of OCH against this fungus was 0.76 and 1.69 g/liter on days 4 and 6 of incubation, respectively. Lesion area and disease incidence in the jujube fruit inoculated with A. alternata were remarkably reduced by the OCH treatments at concentrations higher than 1 g/liter, but 5 g/liter OCH was considered the optimal treatment for inhibiting disease development. OCH also significantly reduced postharvest natural decay, promoted fruit firmness, delayed decline in soluble solids and loss of ascorbic acid, and increased total phenolic compounds during storage at 0°C and 85 to 95% relative humidity. Biochemical evaluations revealed that the activities of the main defense-related enzymes in the jujube fruit, including phenylalanine ammonia-lyase, peroxidase, chitinase, and β-1,3-glucanase, were significantly enhanced (P < 0.05) by OCH treatment. OCH increased superoxide dismutase activity but decreased catalase activity and, consequently, elevated hydrogen peroxide levels in the fruit. These results suggest that OCH might trigger several defense mechanisms in the jujube fruit for disease control in addition to its direct antifungal activity. OCH could be a viable alternative to conventional control of postharvest diseases of horticultural products.

  9. Calculation of a volume effect accompanying an electronic topological transition in pure cerium

    NASA Astrophysics Data System (ADS)

    Ponomaryova, S. O.; Koval', Yu. M.; Ponomaryov, O. P.

    2012-10-01

    An analytic expression for estimating the volume effect accompanying an electronic topological transition (ETT) in pure cerium is derived on the basis of the microscopic Falikov-Ramirez-Kimball model.

  10. Decreased Pseudomonas aeruginosa biofilm formation on nanomodified endotracheal tubes: a dynamic lung model

    PubMed Central

    Machado, Mary C; Webster, Thomas J

    2016-01-01

    Ventilator-associated pneumonia (VAP) is a serious complication of mechanical ventilation that has been shown to be associated with increased mortality rates and medical costs in the pediatric intensive care unit. Currently, there is no cost-effective solution to the problems posed by VAP. Endotracheal tubes (ETTs) that are resistant to bacterial colonization and that inhibit biofilm formation could provide a novel solution to the problems posed by VAP. The objective of this in vitro study was to evaluate differences in the growth of Pseudomonas aeruginosa on unmodified polyvinyl chloride (PVC) ETTs and on ETTs etched with a fungal lipase, Rhizopus arrhizus, to create nanoscale surface features. These differences were evaluated using an in vitro model of the pediatric airway to simulate a ventilated patient in the pediatric intensive care unit. Each experiment was run for 24 hours and was supported by computational models of the ETT. Dynamic conditions within the ETT had an impact on the location of bacterial growth within the tube. These conditions also quantitatively affected bacterial growth especially within the areas of tube curvature. Most importantly, experiments in the in vitro model revealed a 2.7 log reduction in the number (colony forming units/mL) of P. aeruginosa on the nanoroughened ETTs compared to the untreated PVC ETTs after 24 hours. This reduction in total colony forming units/mL along the x-axis of the tube was similar to previous studies completed for Staphylococcus aureus. Thus, this dynamic study showed that lipase etching can create surface features of nanoscale roughness on PVC ETTs that decrease bacterial attachment of P. aeruginosa without the use of antibiotics and may provide clinicians with an effective and inexpensive tool to combat VAP. PMID:27563242

  11. Estimated times to exhaustion at the PWC V O2, PWC HRT, and VT.

    PubMed

    Mielke, Michelle; Housh, Terry J; Malek, Moh H; Beck, Travis W; Hendrix, C Russell; Schmidt, Richard J; Johnson, Glen O

    2008-11-01

    The purpose of this study was to validate the Physical Working Capacity at the Heart Rate Threshold (PWC HRT) and Physical Working Capacity at the Oxygen Consumption Threshold (PWC V O2) tests by 1) using individual power vs. duration relationships to estimate the times to exhaustion (ETTE) at the PWC HRT and PWC V O2, and 2) comparing the power outputs and ETTE values of the PWC HRT and PWC V O2 with those of the ventilatory threshold (VT). Ten adults (mean age +/- SD = 23 +/- 1 years) performed an incremental test to exhaustion on a cycle ergometer for the determination of V O2 peak and VT. The subjects also performed four randomly ordered workbouts to exhaustion at different power outputs (ranging from 98 to 246 W) to determine the PWC V O2, PWC HRT, and power vs. duration relationship. Power curve analyses (y = ax b) were used to define the hyperbolic power vs. duration relationship for each subject and to determine the ETTE at the PWC V O2, PWC HRT, and VT. Two separate one-way repeated-measures analyses of variance indicated that there were significant differences among the fatigue thresholds (PWC V O2 > PWC HRT) and ETTE values (PWC HRT > PWC V O2): PWC V O2 (mean +/- SD = 147 +/- 43 W; ETTE = 21 +/- 3 minutes), PWCHRT (136 +/- 37 W; ETTE = 29 +/- 6 minutes), and VT (143 +/- 44 W; ETTE = 27 +/- 11 minutes). These findings were consistent with previous studies that indicated that the PWC HRT occurred at a lower power output than the PWC V O2. Furthermore, the PWC HRT was maintained for a mean of 29 minutes, whereas the PWC V O2 and VT were maintained for 21 and 27 minutes, respectively. These findings indicate that the ETTE values for the PWC V O2 and PWC HRT were substantially less than those suggested in previous studies. PMID:18978609

  12. Decreased Pseudomonas aeruginosa biofilm formation on nanomodified endotracheal tubes: a dynamic lung model.

    PubMed

    Machado, Mary C; Webster, Thomas J

    2016-01-01

    Ventilator-associated pneumonia (VAP) is a serious complication of mechanical ventilation that has been shown to be associated with increased mortality rates and medical costs in the pediatric intensive care unit. Currently, there is no cost-effective solution to the problems posed by VAP. Endotracheal tubes (ETTs) that are resistant to bacterial colonization and that inhibit biofilm formation could provide a novel solution to the problems posed by VAP. The objective of this in vitro study was to evaluate differences in the growth of Pseudomonas aeruginosa on unmodified polyvinyl chloride (PVC) ETTs and on ETTs etched with a fungal lipase, Rhizopus arrhizus, to create nanoscale surface features. These differences were evaluated using an in vitro model of the pediatric airway to simulate a ventilated patient in the pediatric intensive care unit. Each experiment was run for 24 hours and was supported by computational models of the ETT. Dynamic conditions within the ETT had an impact on the location of bacterial growth within the tube. These conditions also quantitatively affected bacterial growth especially within the areas of tube curvature. Most importantly, experiments in the in vitro model revealed a 2.7 log reduction in the number (colony forming units/mL) of P. aeruginosa on the nanoroughened ETTs compared to the untreated PVC ETTs after 24 hours. This reduction in total colony forming units/mL along the x-axis of the tube was similar to previous studies completed for Staphylococcus aureus. Thus, this dynamic study showed that lipase etching can create surface features of nanoscale roughness on PVC ETTs that decrease bacterial attachment of P. aeruginosa without the use of antibiotics and may provide clinicians with an effective and inexpensive tool to combat VAP. PMID:27563242

  13. Antimony leaching from MSWI bottom ash: modelling of the effect of pH and carbonation.

    PubMed

    Cornelis, Geert; Van Gerven, Tom; Vandecasteele, Carlo

    2012-02-01

    Development of treatment methods to reduce Sb leaching from municipal solid waste incinerator (MSWI) bottom ash, such as accelerated carbonation, is being complicated by insufficient understanding of Sb geochemistry. The leaching of antimonate (Sb(V)) and antimonite (Sb(III)) in MSWI bottom was studied as a function of pH and degree of carbonation. While total (Sb(V)+Sb(III)) leaching was lowest (1.2 mg kg(-1)) at the natural pH (i.e. 10.6) of uncarbonated bottom ash, HPLC-ICP-MS analysis showed that acidification and carbonation increased Sb(V) leaching, but decreased Sb(III) leaching, probably because Sb(III)(OH)(4)(-) became less stable. PHREEQC geochemical modelling suggested that Sb(V) concentrations approached equilibrium with the romeites, i.e. calcium antimonates, Ca(1.13)Sb(2)(OH)(0.26)·0.74H(2)O at pH=10.6 and Ca[Sb(OH)(6)](2) at pH=8. It is hypothesised that not interaction with ettringite but dissolution of romeite controls antimonate leaching in the pH range 8-11 in MSWI bottom ash, because while Ca is preferentially leached from romeite, the mineral structures containing more Ca at higher pH are less soluble. A model was proposed where acidification and carbonation both lead to lower Ca(2+) and/or hydroxyl concentration, which removes Ca(2+) and hydroxyls from the romeite structure and leads to comparably higher Sb(V) concentration in equilibrium with romeite. Sb solubility depends on pH and Ca(2+) availability in this model, which has implications for bottom ash valorisation and risk assessment. PMID:22035902

  14. Comparison of prophylactic effects of polyurethane cylindrical or tapered cuff and polyvinyl chloride cuff endotracheal tubes on ventilator-associated pneumonia.

    PubMed

    Mahmoodpoor, Ata; Peyrovi-far, Ali; Hamishehkar, Hadi; Bakhtyiari, Zhaleh; Mirinezhad, Mir Mousa; Hamidi, Masoud; Golzari, Samad Eslam Jamal

    2013-08-07

    Because microaspiration of contaminated supraglottic secretions past the endotracheal tube cuff is considered to be central in the pathogenesis of pneumonia, improved design of tracheal tubes with new cuff material and shape have reduced the size and number of folds, which together with the addition of suction ports above the cuff to drain pooled subglottic secretions leads to reduced aspiration of oropharyngeal secretions. So we conducted a study to compare the prophylactic effects of polyurethane-cylindrical or tapered cuff and polyvinyl chloride cuff endotracheal tubes (ETT) on ventilator-associated pneumonia. This randomized clinical trial was carried out in a 12 bed surgical intensive care unit. 96 patients expected to require mechanical ventilation more than 96 hours were randomly allocated to one of three following groups: Polyvinyl chloride cuff (PCV) ETT, Polyurethane (PU) cylindrical Sealguard ETT and PU Taperguard ETT. Cuff pressure monitored every three hours 3 days in all patients. Mean cuff pressure didn't have significant difference between three groups during 72 hours. Pneumonia was seen in 11 patients (34%) in group PVC, 8 (25%) in Sealguard and 7 (21%) in Taperguard group. Changes in mean cuff pressure between Sealguard and PVC tubes and also between Taperguard and PVC tubes did not show any significant difference. There was no significant difference in overinflation between three groups. The use of ETT with PU material results in reducing ventilator-associated pneumonia compared to ETT with PVC cuff. In PU tubes Taperguard has less incidence of ventilator-associated pneumonia compared to Sealguard tubes.

  15. Analgesic and anti-inflammatory activities of the ethanol extract of Taxillus tsaii Chiu in mice.

    PubMed

    Liu, Chia-Yu; Chiu, Yung-Jia; Kuo, Chao-Lin; Chien, Tzu-Mei; Wu, Lung-Yuan; Peng, Wen-Huang

    2015-06-01

    Preclinical Research This study was conducted to investigate the analgesic activities and mechanism of anti-inflammatory activities of a 50% ethanol extract of Taxillus tsaii (ETT) in vivo using the acetic acid induced writhing test and formalin induced paw licking in mice. The anti-inflammatory effect of ETT was evaluated using a mouse model of λ-carrageenan (Carr)-induced paw edema. ETT reduced the writhing in the acetic acid assay test at a dose 1.0 g/kg po and reduced the licking time in the late phase of the formalin test at doses of 0.5 and 1.0 g/kg po). Carr-induced paw edema was reduced when ETT (0.5 and 1.0 g/kg po) was administered 3-5 h after Carr injection. ETT (1.0 g/kg po) reduced the level of malondialdehyde in the edemic paw by increasing the activity of antioxidant enzymes, e.g., superoxide dismutase and glutathione reductase, in the liver and reducing TNF-α, IL-1β, and IL-6 activity in the edemic paw. This study demonstrates the analgesic and anti-inflammatory effects of ETT, thus verifying its application in traditional Chinese medicine.

  16. Tin(II) alkoxide hydrolysis products for use as base catalysts

    DOEpatents

    Boyle, Timothy J.

    2002-01-01

    Tin alkoxide compounds are provided with accessible electrons. The compounds are a polymeric tin alkoxide, [Sn(OCH.sub.2 C(CH.sub.3).sub.3).sub.2 ].sub.n, and the hydrolysis products Sn.sub.6 O.sub.4 (OCH.sub.2 C(CH.sub.3).sub.3).sub.4 and Sn.sub.5 O.sub.2 (OCH.sub.2 C(CH.sub.3).sub.3).sub.6. The hydrolysis products are formed by hydrolyzing the [Sn(OCH.sub.2 C(CH.sub.3).sub.3).sub.2 ].sub.n in a solvent with controlled amounts of water, between 0.1 and 2 moles of water per mole of the polymeric tin alkoxide.

  17. The effect of tadalafil on the time to exercise-induced myocardial ischaemia in subjects with coronary artery disease

    PubMed Central

    Patterson, Dean; Kloner, Robert; Effron, Mark; Emmick, Jeffrey; Bedding, Alun; Warner, Margaret; Mitchell, Malcolm; Braat, Simon; MacDonald, Thomas

    2005-01-01

    Objective To investigate the effect of tadalafil on the time to exercise-induced myocardial ischaemia in subjects with coronary artery disease (CAD). Background CAD and erectile dysfunction (ED) share similar risk factors. It is important to know the cardiovascular effects of tadalafil in patients with CAD during physical exertion that is comparable with sexual activity. Methods A randomized, placebo-controlled, double-blind, two-period, crossover study comparing the effects of tadalafil 10 mg and placebo on the time to exercise treadmill test (ETT)-induced myocardial ischaemia in subjects with stable CAD (n = 23; age range: 53–75 years, all exhibited ST-segment depression >1.5 mm at screening ETT at >5METS). Haemodynamic responses to sublingual nitroglycerin (NTG) were assessed before and after ETT. Results Compared with placebo, tadalafil did not significantly affect the time to ETT-induced ischaemia (13 min/31 s vs. 13 min/36 s, respectively). Before exercise, NTG evoked decreases in sitting systolic blood pressure (SBP) that were significantly greater when subjects received tadalafil compared with placebo, and after exercise, more subjects experienced a decrease in SBP <85 mmHg in response to NTG after taking tadalafil vs. placebo. When subjects received tadalafil compared with placebo, SBP was lower at rest (−7 mmHg; −12,-2), during ETT (−10 mmHg; −16, −3), and after ETT (−13 mmHg; −19, −7). Conclusion Tadalafil did not significantly alter the time to ETT-induced ischaemia compared with placebo in subjects with CAD. Tadalafil reduced resting and exercise SBP. Due to the potential for hypotension, the concomitant use of nitrates and tadalafil is contraindicated. PMID:16236035

  18. I-gel as an alternative to endotracheal tube in adult laparoscopic surgeries: A comparative study

    PubMed Central

    Badheka, Jigisha Prahladrai; Jadliwala, Rashida Mohammedi; Chhaya, Vrajeshchandra Amrishbhi; Parmar, Vandana Surendrabhai; Vasani, Amit; Rajyaguru, Ajay Maganlal

    2015-01-01

    BACKGROUND: The tracheal tube is always considered to be the gold standard for laparoscopic surgeries. As conventional laryngoscopy guided endotracheal intubation evokes significant hypertension and tachycardia, we have used I-gel, second generation extraglottic airway device, in an attempt to overcome these drawbacks. We conducted this study to compare haemodynamic changes during insertion, efficacy of ventilation, and complications with the use of I-gel when compared with endotracheal tube (ETT) in laparoscopic surgeries. MATERIALS AND METHODS: A total of 60 American Society of Anaesthesiologists physical status I and II adult patients undergoing elective laparoscopic surgeries were randomly allocated to one of the two groups of 30 patients each: Group-A (I-gel) in which patients airway was secured with appropriate sized I-gel, and Group-B (ETT) in which patients airway was secured with laryngoscopy - guided endotracheal intubation. Ease, attempts and time for insertion of airway device, haemodynamic and ventilatory parameters at different time intervals, and attempts for gastric tube insertion, and perioperative complications were recorded. RESULTS: There was significant rise in pulse rate and mean blood pressure during insertion with use of ETT when compared to I-gel. Furthermore, time required for I-gel insertion was significantly less when compared with ETT. However ease and attempts for airway device insertion, attempts for gastric tube insertion and efficacy of ventilation were comparable between two groups. CONCLUSION: We concluded that I-gel requires less time for insertion with minimal haemodynamic changes when compared to ETT. I-gel also provides adequate positive-pressure ventilation, comparable with ETT. Hence I-gel can be a safe and suitable alternative to ETT for laparoscopic surgeries. PMID:26622115

  19. Geographic access to cancer care: a disparity and a solution.

    PubMed

    Ahamad, Anesa

    2011-09-01

    BACKGROUND The rising cancer incidence in developing countries outpaces easy access to care. Time and effort spent on travel for care is a burden to patients and detracts from patient centredness, efficiency, and equitability. In Trinidad and Tobago, significant distress was observed among patients who made long journeys to the single public cancer clinic. The journey time among non-radiotherapy patients was measured. METHODS Over 19 weekdays in June 2007, the study assessed estimated travel time per visit (ETT), reason for visit for care, and number of visits per patient during their treatment course up to the time of study, and compared the findings with ETT to nearest centres for the US population. RESULTS 1447 episodes of care utilised 5296 h of patient travel time. Median ETT was 3.75 h (IQR 2-5 h, range 0.5-9 h). 74.1% of patients spent 2.25-9 h ETT. 44% of patients spent >4 h ETT. Median number of visits per patient was 34 (IQR 23-43; range 13-62). Median total ETT per patient was 127.5 h. Median ETT to the centre (1.75 h) was eight times greater than in the USA (13 min). More than 70% of patients attended for reasons other than chemotherapy. CONCLUSIONS Cancer patients endured a burden of long travel times in 2007. The prevailing policy of the Ministry of Health to build a single centralised modern centre would not have alleviated this burden. Based on these findings, three outlying cancer clinics were created which now provide non-radiotherapy oncology management of patients nearer their homes.

  20. α-1,6-Mannosylation of N-Linked Oligosaccharide Present on Cell Wall Proteins Is Required for Their Incorporation into the Cell Wall in the Filamentous Fungus Neurospora crassa▿†

    PubMed Central

    Maddi, Abhiram; Free, Stephen J.

    2010-01-01

    The enzyme α-1,6-mannosyltransferase (OCH-1) is required for the synthesis of galactomannans attached to the N-linked oligosaccharides of Neurospora crassa cell wall proteins. The Neurospora crassa och-1 mutant has a tight colonial phenotype and a defective cell wall. A carbohydrate analysis of the och-1 mutant cell wall revealed a 10-fold reduction in the levels of mannose and galactose and a total lack of 1,6-linked mannose residues. Analysis of the integral cell wall protein from wild-type and och-1 mutant cells showed that the mutant cell wall had reduced protein content. The och-1 mutant was found to secrete 18-fold more protein than wild-type cells. Proteomic analysis of the proteins released by the mutant into the growth medium identified seven of the major cell wall proteins. Western blot analysis of ACW-1 and GEL-1 (two glycosylphosphatidylinositol [GPI]-anchored proteins that are covalently integrated into the wild-type cell wall) showed that high levels of these proteins were being released into the medium by the och-1 mutant. High levels of ACW-1 and GEL-1 were also released from the och-1 mutant cell wall by subjecting the wall to boiling in a 1% SDS solution, indicating that these proteins are not being covalently integrated into the mutant cell wall. From these results, we conclude that N-linked mannosylation of cell wall proteins by OCH-1 is required for their efficient covalent incorporation into the cell wall. PMID:20870880

  1. The reactivity of molybdenum pentachloride with ethers: routes to the synthesis of Mo(IV)Cl4 adducts, Mo(V) chlorido-alkoxides and Mo(V) oxydo-chlorides.

    PubMed

    Marchetti, Fabio; Pampaloni, Guido; Zacchini, Stefano

    2013-11-14

    The reactivity of molybdenum pentachloride, 1, with a selection of mono- and diethers was investigated at room temperature in a non-coordinating solvent (dichloromethane). The Mo(IV) complex MoCl4(OMe2)2, 2, was obtained in 75% yield by the reaction of 1 with an excess of Me2O; similarly, MoCl4(κ(2)-L) [L = EtOCH2CH2OEt, 6a; MeOCH2CH(Me)OMe, 6b] were prepared in good yields by 1:1 combination of 1 with the appropriate diether. MoCl5 reacted with OMePh and Et2O affording variable amounts of RCl (R = Me and Et, respectively); MoCl3(OPh)2, 3, was isolated in 60% yield from 1 and OMePh. The reactions of 1 with OMe(t)Bu, O(t)Bu(CH=CH2), MeOCH2CH2OCH2Cl and 1,3-dioxane proceeded with non-selective activation of the organic material. The oxido-complexes Mo2O2Cl4(μ-OMe)2(μ-MeOH), 4, and MoOCl3(MeOH)2, 5, were isolated in modest amounts from 1/OMe(t)Bu, whereas MoOCl3(κ(2)-MeOCH2CH2OCH2Cl), 7, was obtained in 32% yield from 1/MeOCH2CH2OCH2Cl. All of the isolated metal products were characterized by spectroscopic and analytical techniques, and by X-ray diffractometry in the cases of 2, 4, 5, 6b and 7. NMR/GC-MS analyses were carried out in order to outline the fragmentation pathways of the organic reactants. PMID:24005818

  2. Replacement of the carboxylic acid group of prostaglandin F2α with a hydroxyl or methoxy substituent provides biologically unique compounds

    PubMed Central

    Woodward, D F; Krauss, A H-P; Chen, J; Gil, D W; Kedzie, K M; Protzman, C E; Shi, L; Chen, R; Krauss, H A; Bogardus, A; Dinh, H T T; Wheeler, L A; Andrews, S W; Burk, R M; Gac, T; Roof, M B; Garst, M E; Kaplan, L J; Sachs, G; Pierce, K L; Regan, J W; Ross, R A; Chan, M F

    2000-01-01

    Replacement of the carboxylic acid group of PGF2α with the non-acidic substituents hydroxyl (-OH) or methoxy (-OCH3) resulted in an unexpected activity profile.Although PGF2α 1-OH and PGF2α 1-OCH3 exhibited potent contractile effects similar to 17-phenyl PGF2α in the cat lung parenchymal preparation, they were approximately 1000 times less potent than 17-phenyl PGF2α in stimulating recombinant feline and human FP receptors.In human dermal fibroblasts and Swiss 3T3 cells PGF2α 1-OH and PGF2α 1-OCH3 produced no Ca2+ signal until a 1 μM concentration was exceeded. Pretreatment of Swiss 3T3 cells with either 1 μM PGF2α 1-OH or PGF2α 1-OCH3 did not attenuate Ca2+ signal responses produced by PGF2α or fluprostenol. In the rat uterus, PGF2α 1-OH was about two orders of magnitude less potent than 17-phenyl PGF2α whereas PGF2α 1-OCH3 produced only a minimal effect.Radioligand binding studies on cat lung parenchymal plasma membrane preparations suggested that the cat lung parenchyma does not contain a homogeneous population of receptors that equally respond to PGF2α1-OH, PGF2α1-OCH3, and classical FP receptor agonists.Studies on smooth muscle preparations and cells containing DP, EP1, EP2, EP3, EP4, IP, and TP receptors indicated that the activity of PGF2α 1-OH and PGF2α 1-OCH3 could not be ascribed to interaction with these receptors.The potent effects of PGF2α 1-OH and PGF2α 1-OCH3 on the cat lung parenchyma are difficult to describe in terms of interaction with the FP or any other known prostanoid receptor. PMID:10952685

  3. Electrochemical storage cell containing a substituted anisole or di-anisole redox shuttle additive for overcharge protection and suitable for use in liquid organic and solid polymer electrolytes

    DOEpatents

    Kerr, John B.; Tian, Minmin

    2000-01-01

    A electrochemical cell is described comprising an anode, a cathode, a solid polymer electrolyte, and a redox shuttle additive to protect the cell against overcharging and a redox shuttle additive to protect the cell against overcharging selected from the group consisting of: (a) a substituted anisole having the general formula (in an uncharged state): ##STR1## where R.sub.1 is selected from the group consisting of H, OCH.sub.3, OCH.sub.2 CH.sub.3, and OCH.sub.2 phenyl, and R.sub.2 is selected from the group consisting of OCH.sub.3, OCH.sub.2 CH.sub.3, OCH.sub.2 phenyl, and O.sup.- Li.sup.+ ; and (b) a di-anisole compound having the general formula (in an uncharged state): ##STR2## where R is selected from the group consisting of -OCH.sub.3 and -CH.sub.3, m is either 1 or 0, n is either 1 or 0, and X is selected from the group consisting of -OCH.sub.3 (methoxy) or its lithium salt --O.sup.- Li.sup.+. The lithium salt of the di-anisole is the preferred form of the redox shuttle additive because the shuttle anion will then initially have a single negative charge, it loses two electrons when it is oxidized at the cathode, and then moves toward the anode as a single positively charged species where it is then reduced to a single negatively charged species by gaining back two electrons.

  4. Localization artefacts in ultracytochemical ion precipitation reactions.

    PubMed

    von Zglinicki, T; Punkt, K

    1986-01-01

    The precipitation patterns of the following ultracytochemical methods in rat muscle cells were compared and examined critically: the potassium pyroantimonate method for calcium demonstration; the calcium phosphate technique for the Ca2+--ATPase reaction; the formazan reaction for the demonstration of creatine kinase activity (all performed on heart muscle); and the lead phosphate technique for the Mg2+--ATPase reaction in skeletal muscle. Using X-ray microanalysis, it was found that the antimonate precipitate contains only calcium as the precipitated ion in the vast majority of cases. Most probably it consists of pure calcium pyroantimonate. However, in myocytes showing the well-established precipitation pattern, the concentration of calcium was estimated to be about two orders of magnitude higher than the native concentration of total intracellular calcium. It is concluded that calcium ions diffuse freely from the extracellular space and from adjacent cells into cells containing antimonate and are precipitated mostly at sites where heterogeneous nucleation is facilitated by intracellular catalysts (biopolymers). As shown by the similar precipitation patterns for the four reactions compared, these catalysts are not specific to any of these reactions and are most probably neither calcium-binding sites nor sites of any one of the enzymes examined in the native cell.

  5. Photoluminescence properties of a new orange-red-emitting Sm(3+)-La3SbO7 phosphor.

    PubMed

    Li, Zeng-Mei; Deng, Li-Gang; Zhao, Shan-Cang; Zhang, Shu-Qiu; Guo, Chang-Ying; Liang, Jing-Yun; Yue, Hui; Wan, Chun-Yan

    2016-03-01

    The antimonate compound La3SbO7 has high chemical stability, lattice stiffness and thermal stability. Orange-red-emitting antimonate-based phosphors La3SbO7:xSm(3+) (x = 0.02, 0.05, 0.08, 0.10, 0.15, 0.20 and 0.25) were synthesized. The phase structure and photoluminescence properties of these phosphors were investigated. The emission spectrum obtained on excitation at 407 nm contained exclusively the characteristic emissions of Sm(3+) at 568, 608, 654 and 716 nm, which correspond to the transitions from (4)G5/2 to (6)H5/2, (6)H7/2, (6)H9/2 and (6)H11/2 of Sm(3+), respectively. The strongest emission was located at 608 nm due to the (4)G5/2→(6)H7/2 transition of Sm(3+), generating bright orange-red light. The critical quenching concentration of Sm(3+) in La3SbO7:Sm(3+) phosphor was determined as 10% and the energy transfer between Sm(3+) was found to be through an exchange interaction. The International Commission on Illumination chromaticity coordinates of the La3SbO7:0.10Sm(3+) phosphors are located in the orange-red region. The La3SbO7:Sm(3+) phosphors may be potentially used as red phosphors for white light-emitting diodes.

  6. Microgravity and clinorotation cause redistribution of free calcium in sweet clover columella cells

    NASA Technical Reports Server (NTRS)

    Hilaire, E.; Paulsen, A. Q.; Brown, C. S.; Guikema, J. A.; Spooner, B. S. (Principal Investigator)

    1995-01-01

    In higher plants, calcium redistribution is believed to be crucial for the root to respond to a change in the direction of the gravity vector. To test the effects of clinorotation and microgravity on calcium localization in higher plant roots, sweet clover (Melilotus alba L.) seedlings were germinated and grown for two days on a slow rotating clinostat or in microgravity on the US Space Shuttle flight STS-60. Subsequently, the tissue was treated with a fixative containing antimonate (a calcium precipitating agent) during clinorotation or in microgravity and processed for electron microscopy. In root columella cells of clinorotated plants, antimonate precipitates were localized adjacent to the cell wall in a unilateral manner. Columella cells exposed to microgravity were characterized by precipitates mostly located adjacent to the proximal and lateral cell wall. In all treatments some punctate precipitates were associated with vacuoles, amyloplasts, mitochondria, and euchromatin of the nucleus. A quantitative study revealed a decreased number of precipitates associated with the nucleus and the amyloplasts in columella cells exposed to microgravity as compared to ground controls. These data suggest that roots perceive a change in the gravitational field, as produced by clinorotation or space flights, and respond respectively differently by a redistribution of free calcium.

  7. The ether lipid 1-octadecyl-2-methyl-rac-glycero-3-phosphocholine induces expression of fos and jun proto-oncogenes and activates AP-1 transcription factor in human leukaemic cells.

    PubMed Central

    Mollinedo, F; Gajate, C; Modolell, M

    1994-01-01

    The ether lipid analogue 1-octadecyl-2-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3) has been recently shown to induce apoptosis in the human leukaemic HL-60 and U937 myeloid cell lines [Mollinedo, Martinez-Dalmau and Modolell (1993) Biochem. Biophys. Res. Commun. 192, 603-609]. We have found that ET-18-OCH3 is also able to promote apoptosis in the human leukaemic Jurkat T lymphoid cell line. This lymphoid cell line as well as the two myeloid HL-60 and U937 cell lines incorporated significant amounts of exogenously added radiolabelled ET-18-OCH3. Addition of ET-18-OCH3 to these human leukaemic cells induced an increase in the steady-state mRNA levels of fos and jun proto-oncogenes, components of the transcription factor AP-1. These increases in fos and jun mRNA levels were associated with the activation of the AP-1 transcription factor after addition of ET-18-OCH3 to human leukaemic cells, as assessed by an enhanced binding activity of transcription factor AP-1 to its cognate DNA sequence as well as by stimulation of transcription from an AP-1 enhancer element. These data demonstrate that the ether lipid ET-18-OCH3 can affect gene expression by inducing expression of fos and jun proto-oncogenes and by modulating the activity of transcription factor AP-1. Images Figure 2 Figure 3 Figure 4 PMID:8092982

  8. Perspectives on Pentaerythritol Tetranitrate (PETN) Decomposition

    SciTech Connect

    Chambers, D; Brackett, C; Sparkman, D O

    2002-07-01

    This report evaluates the large body of work involving the decomposition of PETN and identifies the major decomposition routes and byproducts. From these studies it becomes apparent that the PETN decomposition mechanisms and the resulting byproducts are primarily determined by the chemical environment. In the absence of water, PETN can decompose through the scission of the O-NO{sup 2} bond resulting in the formation of an alkoxy radical and NO{sub 2}. Because of the relatively high reactivity of both these initial byproducts, they are believed to drive a number of autocatalytic reactions eventually forming (NO{sub 2}OCH{sub 2}){sub 3}CCHO, (NO{sub 2}OCH{sub 2}){sub 2}C=CHONO{sub 2}, NO{sub 2}OCH=C=CHONO{sub 2}, (NO{sub 2}OCH{sub 2}){sub 3}C-NO{sub 2}, (NO{sub 2}OCH{sub 2}){sub 2}C(NO{sub 2}){sub 2}, NO{sub 2}OCH{sub 2}C(NO{sub 2}){sub 3}, and C(NO{sub 2}){sub 4} as well as polymer-like species such as di-PEHN and tri-PEON. Surprisingly, the products of many of these proposed autocatalytic reactions have never been analytically validated. Conversely, in the presence of water, PETN has been shown to decompose primarily to mono, di, and tri nitrates of pentaerythritol.

  9. The effects of closed endotracheal suction on ventilation during conventional and high-frequency oscillatory ventilation.

    PubMed

    Kiraly, Nicholas J; Tingay, David G; Mills, John F; Morley, Colin J; Dargaville, Peter A; Copnell, Beverley

    2009-10-01

    In newborn infants, closed endotracheal tube (ETT) suction may reduce associated adverse effects, but it is not clear whether ventilation is maintained during the procedure. We aimed to determine the effect of ETT size, catheter size, and suction pressure on ventilation parameters measured distal to the ETT. Suction was performed on a test lung, ventilated with conventional (CMV) and high-frequency oscillatory ventilation (HFOV) using ETT sizes 2.5-4.0 mm, catheter sizes 5-8 French gauge (Fr), and suction pressures 80-200 mm Hg. Tracheal and circuit peak inspiratory pressure, positive end-expiratory pressure, and tracheal tidal volume (VT) were recorded for each suction episode. During both CMV and HFOV, tracheal pressures and VT were considerably reduced by suctioning; this reduction was dependent on the combination of ETT, catheter, and suction pressure. Loss of VT, inflation pressure (CMV), and pressure amplitude (HFOV) occurred primarily with insertion of the catheter, and loss of end-expiratory pressure (CMV) and mean tracheal pressure (HFOV) occurred with the application of suction. Circuit pressures were reduced to lesser degree. We conclude that airway pressures and VT are not maintained during closed endotracheal suction with either CMV or HFOV, and choice of equipment and settings will affect the degree of interruption to ventilation.

  10. Escherichia coli Type III Secretion System 2 ATPase EivC Is Involved in the Motility and Virulence of Avian Pathogenic Escherichia coli.

    PubMed

    Wang, Shaohui; Liu, Xin; Xu, Xuan; Yang, Denghui; Wang, Dong; Han, Xiangan; Shi, Yonghong; Tian, Mingxing; Ding, Chan; Peng, Daxin; Yu, Shengqing

    2016-01-01

    Type III secretion systems (T3SSs) are crucial for bacterial infections because they deliver effector proteins into host cells. The Escherichia coli type III secretion system 2 (ETT2) is present in the majority of E. coli strains, and although it is degenerate, ETT2 regulates bacterial virulence. An ATPase is essential for T3SS secretion, but the function of the ETT2 ATPase has not been demonstrated. Here, we show that EivC is homologous to the β subunit of F0F1 ATPases and it possesses ATPase activity. To investigate the effects of ETT2 ATPase EivC on the phenotype and virulence of avian pathogenic Escherichia coli (APEC), eivC mutant and complemented strains were constructed and characterized. Inactivation of eivC led to impaired flagella production and augmented fimbriae on the bacterial surface, and, consequently, reduced bacterial motility. In addition, the eivC mutant strain exhibited attenuated virulence in ducks, diminished serum resistance, reduced survival in macrophage cells and in ducks, upregulated fimbrial gene expression, and downregulated flagellar and virulence gene expression. The expression of the inflammatory cytokines interleukin (IL)-1β and IL-8 were increased in HD-11 macrophages infected with the eivC mutant strain, compared with the wild-type strain. These virulence-related phenotypes were restored by genetic complementation. These findings demonstrate that ETT2 ATPase EivC is involved in the motility and pathogenicity of APEC. PMID:27630634

  11. Escherichia coli Type III Secretion System 2 ATPase EivC Is Involved in the Motility and Virulence of Avian Pathogenic Escherichia coli

    PubMed Central

    Wang, Shaohui; Liu, Xin; Xu, Xuan; Yang, Denghui; Wang, Dong; Han, Xiangan; Shi, Yonghong; Tian, Mingxing; Ding, Chan; Peng, Daxin; Yu, Shengqing

    2016-01-01

    Type III secretion systems (T3SSs) are crucial for bacterial infections because they deliver effector proteins into host cells. The Escherichia coli type III secretion system 2 (ETT2) is present in the majority of E. coli strains, and although it is degenerate, ETT2 regulates bacterial virulence. An ATPase is essential for T3SS secretion, but the function of the ETT2 ATPase has not been demonstrated. Here, we show that EivC is homologous to the β subunit of F0F1 ATPases and it possesses ATPase activity. To investigate the effects of ETT2 ATPase EivC on the phenotype and virulence of avian pathogenic Escherichia coli (APEC), eivC mutant and complemented strains were constructed and characterized. Inactivation of eivC led to impaired flagella production and augmented fimbriae on the bacterial surface, and, consequently, reduced bacterial motility. In addition, the eivC mutant strain exhibited attenuated virulence in ducks, diminished serum resistance, reduced survival in macrophage cells and in ducks, upregulated fimbrial gene expression, and downregulated flagellar and virulence gene expression. The expression of the inflammatory cytokines interleukin (IL)-1β and IL-8 were increased in HD-11 macrophages infected with the eivC mutant strain, compared with the wild-type strain. These virulence-related phenotypes were restored by genetic complementation. These findings demonstrate that ETT2 ATPase EivC is involved in the motility and pathogenicity of APEC.

  12. Escherichia coli Type III Secretion System 2 ATPase EivC Is Involved in the Motility and Virulence of Avian Pathogenic Escherichia coli

    PubMed Central

    Wang, Shaohui; Liu, Xin; Xu, Xuan; Yang, Denghui; Wang, Dong; Han, Xiangan; Shi, Yonghong; Tian, Mingxing; Ding, Chan; Peng, Daxin; Yu, Shengqing

    2016-01-01

    Type III secretion systems (T3SSs) are crucial for bacterial infections because they deliver effector proteins into host cells. The Escherichia coli type III secretion system 2 (ETT2) is present in the majority of E. coli strains, and although it is degenerate, ETT2 regulates bacterial virulence. An ATPase is essential for T3SS secretion, but the function of the ETT2 ATPase has not been demonstrated. Here, we show that EivC is homologous to the β subunit of F0F1 ATPases and it possesses ATPase activity. To investigate the effects of ETT2 ATPase EivC on the phenotype and virulence of avian pathogenic Escherichia coli (APEC), eivC mutant and complemented strains were constructed and characterized. Inactivation of eivC led to impaired flagella production and augmented fimbriae on the bacterial surface, and, consequently, reduced bacterial motility. In addition, the eivC mutant strain exhibited attenuated virulence in ducks, diminished serum resistance, reduced survival in macrophage cells and in ducks, upregulated fimbrial gene expression, and downregulated flagellar and virulence gene expression. The expression of the inflammatory cytokines interleukin (IL)-1β and IL-8 were increased in HD-11 macrophages infected with the eivC mutant strain, compared with the wild-type strain. These virulence-related phenotypes were restored by genetic complementation. These findings demonstrate that ETT2 ATPase EivC is involved in the motility and pathogenicity of APEC. PMID:27630634

  13. Discordance of exercise thallium testing with coronary arteriography in patients with atypical presentations

    NASA Technical Reports Server (NTRS)

    Bungo, M. W.; Leland, O. S., Jr.

    1983-01-01

    Eighty-one patients with diagnostically difficult clinical presentations suggesting coronary artery disease underwent symptom-limited maximal-exercise treadmill testing (ETT) and exercise radionuclide scanning with thallium-201 followed by coronary angiography. Results showed that in nearly half of the patients (47%) these tests were in agreement, while either exercise thallium or ETT was positive in 94% of patients with coronary artery disease. It was found that agreement between exercise thallium and ETT tests predicted disease in 92% of the instances or excluded disease in 82% of the instances. It is concluded that despite frequent discord between these two tests in 53% of the cases, a significant gain in exclusive diagnostic capability is realized when applied to a patient population anticipated to have a disease prevalence equal to the 67% encountered in this study.

  14. The unusual amino acid l-ergothioneine is a physiologic cytoprotectant

    PubMed Central

    Paul, BD; Snyder, SH

    2010-01-01

    Ergothioneine (ET) is an unusual sulfur-containing derivative of the amino acid, histidine, which is derived exclusively through the diet. Although ET was isolated a century ago, its physiologic function has not been clearly established. Recently, a highly specific transporter for ET (ETT) was identified in mammalian tissues, which explains abundant tissue levels of ET and implies a physiologic role. Using RNA interference, we depleted cells of its transporter. Cells lacking ETT are more susceptible to oxidative stress, resulting in increased mitochondrial DNA damage, protein oxidation and lipid peroxidation. ETT is concentrated in mitochondria, suggesting a specific role in protecting mitochondrial components such as DNA from oxidative damage associated with mitochondrial generation of superoxide. In combating cytotoxic effects of pyrogallol, a known superoxide generator, ET is as potent as glutathione. Because of its dietary origin and the toxicity associated with its depletion, ET may represent a new vitamin whose physiologic roles include antioxidant cytoprotection. PMID:19911007

  15. Perioperative and anesthetic management of complete tracheal rupture in one dog and one cat.

    PubMed

    Morath, Ute; Gendron, Karine; Revés, Nuria Vizcaíno; Adami, Chiara

    2015-01-01

    The authors describe two animals (one dog and one cat) that were presented with severe respiratory distress after trauma. Computerized tomographic imaging under general anesthesia revealed, in both cases, complete tracheal transection. Hypoxic episodes during anesthesia were relieved by keeping the endotracheal tube (ETT) positioned in the cranial part of the transected trachea and by allowing spontaneous breathing. Surgical preparation was performed quickly, and patients were kept in a sternal position to improve ventilation and oxygenation, and were only turned into dorsal recumbency shortly before surgical incision. A sterile ETT was guided into the distal part of the transected trachea by the surgeon, at which point mechanical ventilation was started. Both animals were successfully discharged from hospital a few days after surgery. Rapid and well-coordinated teamwork seemed to contribute to the good outcome. Precise planning and communication between anesthetists, surgeons, and technicians, as well as a quick course of action prior to correct ETT positioning helped to overcome critical phases.

  16. Lung ultrasound associated to capnography to verify correct endotracheal tube positioning in prehospital.

    PubMed

    Brun, Pierre-Marie; Bessereau, Jacques; Cazes, Nicolas; Querellou, Emgan; Chenaitia, Hichem

    2012-11-01

    Endotracheal intubation is the “gold standard” of the control of airway patency but is associated with nonnegligible morbidity rates. A rapid detection of esophageal intubation is essential. Capnography is considered the reference technique for correct endotracheal tube (ETT) positioning confirmation. However, capnography can provide false-positive and false-negative results in some situations. Recently, the ultrasound assessment has been studied for confirming ETT placement. Despite of few trials, the ultrasound procedure may enhance physician confidence and decision making in airway management. We report the case of a 52-year-old female patient presenting cardiorespiratory failure. During cardiopulmonary resuscitation, there was a sudden absence of end-tidal CO2 capnographic detection. Correct tube positioning could not be ascertained by auscultation because the environment had become extremely noisy. However, TM-mode (Time Motion--mode) lung ultrasound revealed bilateral pleural sliding during insufflation with the self-filling balloon, thus confirming correct ETT positioning.

  17. Interface-Located Photothermoelectric Effect of Organic Thermoelectric Materials in Enabling NIR Detection.

    PubMed

    Huang, Dazhen; Zou, Ye; Jiao, Fei; Zhang, Fengjiao; Zang, Yaping; Di, Chong-an; Xu, Wei; Zhu, Daoben

    2015-05-01

    Organic photothermoelectric (PTE) materials are promising candidates for various photodetection applications. Herein, we report on poly[Cux(Cu-ett)]:PVDF, which is an excellent polymeric thermoelectric composite, possesses unprecedented PTE properties. The NIR light irradiation on the poly[Cu(x)(Cu-ett)]:PVDF film could induce obvious enhancement in Seebeck coefficient from 52 ± 1.5 to 79 ± 5.0 μV/K. By taking advantage of prominent photothermoelectric effect of poly[Cu(x)(Cu-ett)]:PVDF, an unprecedented voltage of 12 mV was obtained. This excellent performance enables its promising applications in electricity generation from solar energy and NIR detection to a wide range of light intensities ranging from 1.7 mW/cm(2) to 17 W/cm(2). PMID:25875974

  18. Enthalpy of formation of anisole: implications for the controversy on the O-H bond dissociation enthalpy in phenol.

    PubMed

    Simões, Ricardo G; Agapito, Filipe; Diogo, Hermínio P; da Piedade, Manuel E Minas

    2014-11-20

    Significant discrepancies in the literature data for the enthalpy of formation of gaseous anisole, ΔfHmo(PhOCH3, g), have fueled an ongoing controversy regarding the most reliable enthalpy of formation of the phenoxy radical and of the gas phase O-H bond dissociation enthalpy, DHo(PhO-H), in phenol. In the present work ΔfHmo(PhOCH3, g) was reassessed using a combination of calorimetric determinations and high-level (W2-F12) ab initio calculations. Static-bomb combustion calorimetry led to the standard molar enthalpy of formation of liquid anisole at 298.15 K, ΔfHmo(PhOCH3, l) = −(117.1 ± 1.4) kJ·mol(-1). The corresponding enthalpy of vaporization was obtained as, ΔvapHmo(PhOCH3) = 46.41 ± 0.26 kJ·mol(-1), by Calvet-drop microcalorimetry. These results give ΔfHmo(PhOCH3, g) = −(70.7 ± 1.4) kJ·mol(-1), in excellent agreement with ΔfHmo(PhOCH3, g) = −(70.8 ± 3.2) kJ·mol(-1), obtained from the W2-F12 calculations. The ΔfHmo(PhOCH3, g) here recommended leads to ΔfHmo(PhO•, g) = 55.5 ± 2.4 kJ·mol(-)1 and DH°(PhO-H) = 368.1 ± 2.6 kJ·mol(-1).

  19. Presolvated Electron Reaction with Methylacetoacetate: Electron Localization, Proton-Deuteron Exchange, and H-atom Abstraction

    PubMed Central

    Petrovici, Alex; Adhikary, Amitava; Kumar, Anil; Sevilla, Michael D.

    2015-01-01

    Radiation-produced electrons initiate various reaction processes that are important to radiation damage to biomolecules. In this work, the site of attachment of the prehydrated electrons with methylacetoacetate (MAA, CH3-CO-CH2-CO-OCH3) at 77 K and subsequent reactions of the anion radical (CH3-CO•−-CH2-CO-OCH3) in the temperature range (77 to ca. 170 K) have been investigated in homogeneous H2O and D2O aqueous glasses by electron spin resonance (ESR) spectroscopy. At 77 K, the prehydrated electron attaches to MAA forming the anion radical in which the electron is delocalized over the two carbonyl groups. This species readily protonates to produce the protonated electron adduct radical CH3-C(•)OH-CH2-CO-OCH3. The ESR spectrum of CH3-C(•)OH-CH2-CO-OCH3 in H2O shows line components due to proton hyperfine couplings of the methyl and methylene groups. Whereas, the ESR spectrum of CH3-C(•)OH-CH2-CO-OCH3 in D2O glass shows only the line components due to proton hyperfine couplings of CH3 group. This is expected since the methylen protons in MAA are readily exchangeable in D2O. On stepwise annealing to higher temperatures (ca. 150 to 170 K), CH3-C(•)OH-CH2-CO-OCH3 undergoes bimolecular H-atom abstraction from MAA to form the more stable radical, CH3-CO-CH•-CO-OCH3. Theoretical calculations using density functional theory (DFT) support the radical assignments. PMID:25255751

  20. Retrosynthetic approach to the design of molybdenum-magnesium oxoalkoxides.

    PubMed

    Kuznetsov, Denis A; Fedyanin, Ivan V; Lyssenko, Konstantin A; Bazhenova, Tamara A

    2014-09-14

    The reaction of MoCl5 methanolysis in the presence of magnesium ions was shown to produce an extensive row of heterobimetallic Mg-Mo(V, VI) oxomethoxides of different nuclearity ranging from 4 for [Mg2(CH3OH)4Mo2O2(OCH3)10] (1) to 26 for [Mg(DMF)3(CH3OH)3]2[Mo22Mg4O48(OCH3)28(DMF)6] (2) with the latter possessing a ring morphology. Examination of [Mo6O12(OCH3)16Mg4(CH3OH)6] (3), [Mo6O12(OCH3)12Mg2(DMF)4] (4a), and [Mo6O16(OCH3)4Mg2(DMF)8] (5a) X-ray structures revealed the presence of the well known tetranuclear core {Mo4O8(OCH3)2}(2+) thus similar reactivity patterns leading to their formation were assumed. For convenient synthesis of such heterobimetallic oxoalkoxides, the retrosynthetic approach based on speculative deconstruction of a target molecule onto simpler fragments was suggested and successfully employed. Namely, the reaction of the stoichiometric amounts of appropriately chosen Mo(V), Mo(VI) and Mg(2+) synthons led to their assembling resulting in the formation of heterometallic clusters 3, 5a and [Mo6O12(OCH3)12Mg2(CH3OH)4]·2CH3OH (4b) characterized by means of elemental analysis, UV-Vis, IR spectroscopy, and X-ray crystallography. PMID:25019529

  1. Clinical Evaluation of Heart Failure: Agreement among Tests.

    PubMed

    Pandey, Amit K; Penny, William F; Bhargava, Valmik; Lai, N Chin; Xu, Ronghui; Hammond, H Kirk

    2016-01-01

    Methods commonly used clinically to assess cardiac function in patients with heart failure include ejection fraction (EF), exercise treadmill testing (ETT), and symptom evaluation. Although these approaches are useful in evaluating patients with heart failure, there are at times substantial mismatches between individual assessments. For example, ETT results are often discordant with EF, and patients with minimal symptoms sometimes have surprisingly low EFs. To better define the relationship of these methods of assessment, we studied 56 patients with heart failure with reduced EF (HFrEF) who underwent measurement of ETT duration, EF by echocardiography, quantitative symptom evaluation, and LV peak dP/dt (rate of left ventricular pressure development and decline, measured invasively). Correlations were determined among these four tests in order to assess the relationship of EF, ETT, and symptoms against LV peak dP/dt. In addition, we sought to determine whether EF, ETT, and symptoms correlated with each other. Overall, correlations were poor. Only 15 of 63 total correlations (24%) were significant (p < 0.05). EF correlated most closely with LV peak -dP/dt. Linear regression analysis indicated that EF, ETT, and symptoms taken together predicted LV peak dP/dt better than any one measure alone. We conclude that clinical tests used to assess LV function in patients with HFrEF may not be as accurate or correlate as well as expected. All three clinical measures considered together may be the best representation of cardiac function in HFrEF patients currently available. PMID:27537778

  2. Efficacy of Hi-Lo Evac Endotracheal Tube in Prevention of Ventilator-Associated Pneumonia in Mechanically Ventilated Poisoned Patients.

    PubMed

    Ghoochani Khorasani, Ahmad; Shadnia, Shahin; Mashayekhian, Mohammad; Rahimi, Mitra; Aghabiklooei, Abbas

    2016-01-01

    Background. Ventilator-associated pneumonia (VAP) is the most common health care-associated infection. To prevent this complication, aspiration of subglottic secretions using Hi-Lo Evac endotracheal tube (Evac ETT) is a recommended intervention. However, there are some reports on Evac ETT dysfunction. We aimed to compare the incidence of VAP (per ventilated patients) in severely ill poisoned patients who were intubated using Evac ETT versus conventional endotracheal tubes (C-ETT) in our toxicology ICU. Materials and Methods. In this clinical randomized trial, 91 eligible patients with an expected duration of mechanical ventilation of more than 48 hours were recruited and randomly assigned into two groups: (1) subglottic secretion drainage (SSD) group who were intubated by Evac ETT (n = 43) and (2) control group who were intubated by C-ETT (n = 48). Results. Of the 91 eligible patients, 56 (61.5%) were male. VAP was detected in 24 of 43 (55.8%) patients in the case group and 23 of 48 (47.9%) patients in the control group (P = 0.45). The most frequently isolated microorganisms were S. aureus (54.10%) and Acinetobacter spp. (19.68%). The incidence of VAP and ICU length of stay were not significantly different between the two groups, but duration of intubation was statistically different and was longer in the SSD group. Mortality rate was less in SSD group but without a significant difference (P = 0.68). Conclusion. The SSD procedure was performed intermittently with one-hour intervals using 10 mL syringe. Subglottic secretion drainage does not significantly reduce the incidence of VAP in patients receiving MV. This strategy appears to be ineffective in preventing VAP among ICU patients. PMID:27651976

  3. Efficacy of Hi-Lo Evac Endotracheal Tube in Prevention of Ventilator-Associated Pneumonia in Mechanically Ventilated Poisoned Patients

    PubMed Central

    Mashayekhian, Mohammad; Rahimi, Mitra; Aghabiklooei, Abbas

    2016-01-01

    Background. Ventilator-associated pneumonia (VAP) is the most common health care-associated infection. To prevent this complication, aspiration of subglottic secretions using Hi-Lo Evac endotracheal tube (Evac ETT) is a recommended intervention. However, there are some reports on Evac ETT dysfunction. We aimed to compare the incidence of VAP (per ventilated patients) in severely ill poisoned patients who were intubated using Evac ETT versus conventional endotracheal tubes (C-ETT) in our toxicology ICU. Materials and Methods. In this clinical randomized trial, 91 eligible patients with an expected duration of mechanical ventilation of more than 48 hours were recruited and randomly assigned into two groups: (1) subglottic secretion drainage (SSD) group who were intubated by Evac ETT (n = 43) and (2) control group who were intubated by C-ETT (n = 48). Results. Of the 91 eligible patients, 56 (61.5%) were male. VAP was detected in 24 of 43 (55.8%) patients in the case group and 23 of 48 (47.9%) patients in the control group (P = 0.45). The most frequently isolated microorganisms were S. aureus (54.10%) and Acinetobacter spp. (19.68%). The incidence of VAP and ICU length of stay were not significantly different between the two groups, but duration of intubation was statistically different and was longer in the SSD group. Mortality rate was less in SSD group but without a significant difference (P = 0.68). Conclusion. The SSD procedure was performed intermittently with one-hour intervals using 10 mL syringe. Subglottic secretion drainage does not significantly reduce the incidence of VAP in patients receiving MV. This strategy appears to be ineffective in preventing VAP among ICU patients.

  4. Clinical Evaluation of Heart Failure: Agreement among Tests

    PubMed Central

    Pandey, Amit K.; Penny, William F.; Bhargava, Valmik; Lai, N. Chin; Xu, Ronghui; Hammond, H. Kirk

    2016-01-01

    Methods commonly used clinically to assess cardiac function in patients with heart failure include ejection fraction (EF), exercise treadmill testing (ETT), and symptom evaluation. Although these approaches are useful in evaluating patients with heart failure, there are at times substantial mismatches between individual assessments. For example, ETT results are often discordant with EF, and patients with minimal symptoms sometimes have surprisingly low EFs. To better define the relationship of these methods of assessment, we studied 56 patients with heart failure with reduced EF (HFrEF) who underwent measurement of ETT duration, EF by echocardiography, quantitative symptom evaluation, and LV peak dP/dt (rate of left ventricular pressure development and decline, measured invasively). Correlations were determined among these four tests in order to assess the relationship of EF, ETT, and symptoms against LV peak dP/dt. In addition, we sought to determine whether EF, ETT, and symptoms correlated with each other. Overall, correlations were poor. Only 15 of 63 total correlations (24%) were significant (p < 0.05). EF correlated most closely with LV peak -dP/dt. Linear regression analysis indicated that EF, ETT, and symptoms taken together predicted LV peak dP/dt better than any one measure alone. We conclude that clinical tests used to assess LV function in patients with HFrEF may not be as accurate or correlate as well as expected. All three clinical measures considered together may be the best representation of cardiac function in HFrEF patients currently available. PMID:27537778

  5. Efficacy of Hi-Lo Evac Endotracheal Tube in Prevention of Ventilator-Associated Pneumonia in Mechanically Ventilated Poisoned Patients

    PubMed Central

    Mashayekhian, Mohammad; Rahimi, Mitra; Aghabiklooei, Abbas

    2016-01-01

    Background. Ventilator-associated pneumonia (VAP) is the most common health care-associated infection. To prevent this complication, aspiration of subglottic secretions using Hi-Lo Evac endotracheal tube (Evac ETT) is a recommended intervention. However, there are some reports on Evac ETT dysfunction. We aimed to compare the incidence of VAP (per ventilated patients) in severely ill poisoned patients who were intubated using Evac ETT versus conventional endotracheal tubes (C-ETT) in our toxicology ICU. Materials and Methods. In this clinical randomized trial, 91 eligible patients with an expected duration of mechanical ventilation of more than 48 hours were recruited and randomly assigned into two groups: (1) subglottic secretion drainage (SSD) group who were intubated by Evac ETT (n = 43) and (2) control group who were intubated by C-ETT (n = 48). Results. Of the 91 eligible patients, 56 (61.5%) were male. VAP was detected in 24 of 43 (55.8%) patients in the case group and 23 of 48 (47.9%) patients in the control group (P = 0.45). The most frequently isolated microorganisms were S. aureus (54.10%) and Acinetobacter spp. (19.68%). The incidence of VAP and ICU length of stay were not significantly different between the two groups, but duration of intubation was statistically different and was longer in the SSD group. Mortality rate was less in SSD group but without a significant difference (P = 0.68). Conclusion. The SSD procedure was performed intermittently with one-hour intervals using 10 mL syringe. Subglottic secretion drainage does not significantly reduce the incidence of VAP in patients receiving MV. This strategy appears to be ineffective in preventing VAP among ICU patients. PMID:27651976

  6. Examining the relationship between exercise tolerance and isoproterenol-based cardiac reserve in murine models of heart failure.

    PubMed

    Richards, Daniel A; Bao, Weike; Rambo, Mary V; Burgert, Mark; Jucker, Beat M; Lenhard, Stephen C

    2013-05-01

    The loss of cardiac reserve is, in part, responsible for exercise intolerance in late-stage heart failure (HF). Exercise tolerance testing (ETT) has been performed in mouse models of HF; however, treadmill performance and at-rest cardiac indexes determined by magnetic resonance imaging (MRI) rarely correlate. The present study adopted a stress-MRI technique for comparison with ETT in HF models, using isoproterenol (ISO) to evoke cardiac reserve responses. Male C57BL/6J mice were randomly subjected to myocardial infarction (MI), transverse aortic constriction (TAC), or sham surgery under general anesthesia. Mice underwent serial ETT on a graded treadmill with follow-up ISO stress-MRI. TAC mice showed consistent exercise intolerance, with a 16.2% reduction in peak oxygen consumption vs. sham at 15-wk postsurgery (WPS). MI and sham mice had similar peak oxygen consumption from 7 WPS onward. Time to a respiratory exchange ratio of 1.0 correlated with ETT distance (r = 0.64; P < 0.001). The change in ejection fraction under ISO stress was reduced in HF mice at 4 WPS [10.1 ± 3.9% change (Δ) and 8.9 ± 3.5%Δ in MI and TAC, respectively, compared with 32.0 ± 3.5%Δ in sham; P < 0.001]. However, cardiac reserve differences between surgery groups were not observed at 16 WPS in terms of ejection fraction or cardiac output. In addition, ETT did not correlate with cardiac indexes under ISO stress. In conclusion, ISO stress was unable to reflect consistent differences in ETT between HF and healthy mice, suggesting cardiac-specific indexes are not the sole factors in defining exercise intolerance in mouse HF models.

  7. The minimal leak test technique for endotracheal cuff maintenance.

    PubMed

    DA, Harvie; Jn, Darvall; M, Dodd; A, De La Cruz; M, Tacey; Rl, D'Costa; D, Ward

    2016-09-01

    Endotracheal tube (ETT) cuff pressure management is an essential part of airway management in intubated and mechanically ventilated patients. Both under- and over-inflation of the ETT cuff can lead to patient complications, with an ideal pressure range of 20-30 cmH2O defined. A range of techniques are employed to ensure adequate ETT cuff inflation, with little comparative data. We performed an observational cross-sectional study in a tertiary metropolitan ICU, assessing the relationship between the minimal leak test and cuff manometry. Forty-five mechanically ventilated patients, over a three-month period, had ETT cuff manometry performed at the same time as their routine cuff maintenance (minimal leak test). Bedside nurse measurements were compared with investigator measurements. At the endpoint of cuff inflation, 20 of 45 patients (44%) had cuff pressures between 20 and 30 cmH2O; 11 of 45 patients (24%) had cuff pressures <20 cmH2O; 14 of 45 patients (31%) had cuff pressures ≥30 cmH2O. Univariate analysis demonstrated an association between both patient obesity and female gender requiring less ETT cuff volume (P=0.008 and P <0.001 respectively), though this association was lost on multivariate analysis. No association was demonstrated between any measured variables and cuff pressures. Inter-operator reliability in performing the minimal leak test showed no evidence of bias between nurse and investigators (Pearson coefficient = 0.897). We conclude the minimal leak test for maintenance of ETT cuffs leads to both over- and under-inflation, and alternative techniques, such as cuff manometry, should be employed. PMID:27608343

  8. Obstruction of a non-resterilized reinforced endotracheal tube during craniotomy under general anesthesia

    PubMed Central

    Itani, Omar; Mallat, Claude; Jazzar, Mohammad; Hammoud, Rola; Shaaban, Jamil

    2015-01-01

    Many cases of reinforced endotracheal tube (ETT) obstruction were reported in the literature. In most of these cases, the obstruction was related to the use of a resterilized tube with or without the use of nitrous oxide (N2O). Resterilization and autoclaving of the tube may result in dissection or formation of a bleb between the two layers of the tube that may expand after the use of N2O. We describe a case of acute non-resterilized reinforced ETT obstruction, by bleb formation, during occipital craniotomy under general anesthesia. PMID:26417140

  9. Obstruction of a non-resterilized reinforced endotracheal tube during craniotomy under general anesthesia.

    PubMed

    Itani, Omar; Mallat, Claude; Jazzar, Mohammad; Hammoud, Rola; Shaaban, Jamil

    2015-01-01

    Many cases of reinforced endotracheal tube (ETT) obstruction were reported in the literature. In most of these cases, the obstruction was related to the use of a resterilized tube with or without the use of nitrous oxide (N2O). Resterilization and autoclaving of the tube may result in dissection or formation of a bleb between the two layers of the tube that may expand after the use of N2O. We describe a case of acute non-resterilized reinforced ETT obstruction, by bleb formation, during occipital craniotomy under general anesthesia. PMID:26417140

  10. Decreased sensitivity to 1-O-octadecyl-2-O-methyl-glycerophosphocholine in MCF-7 cells adapted for serum-free growth correlates with constitutive association of Raf-1 with cellular membranes.

    PubMed

    Samadder, P; Arthur, G

    1999-10-01

    We have previously shown that inhibition of MCF-7 cell proliferation by 1-O-octadecyl-2-O-methyl-glycerophosphocholine (ET-18-OCH3) is linked to a drug-induced decrease in membrane Raf-1 levels and the subsequent inhibition of mitogen-activated protein (MAP) kinase activation in response to growth factor stimulation. We now report that adaptation of MCF-7 cells for growth in a serum-free formulation results in decreased sensitivity to growth inhibition by ET-18-OCH3. The decrease in ET-18-OCH3 sensitivity occurred progressively during the adaptation process and correlated with the presence of increasing amounts of inactive Raf-1 that stably associated with MCF-7 cell membranes. ET-18-OCH3 sensitivity could be restored by growing the adapted cells in serum-containing medium, which resulted in the loss of membrane-associated Raf-1. In human normal mammary epithelial cells, which are insensitive to ET-18-OCH3, Raf-1 was also associated with membranes in quiescent cells. In both cell types, incubation with ET-18-OCH3 had no effect on the membrane-Raf-1 levels, suggesting that ET-18-OCH3-induced reduction of Raf-1 levels in growth factor-stimulated MCF-7 cells is due to inhibition of Raf translocation. The activation and termination of the MAP kinase pathway in response to growth factors in the adapted MCF-7 cells and HNME cells occurred without changes to membrane Raf-1 levels. Because membrane translocation is not required to activate Raf in these cells, inhibition of Raf translocation by ET-18-OCH3 subsequent to cell stimulation has no effect on the activation of the membrane-bound Raf and, consequently, the activation of the MAP kinase pathway. The ability of the cells to activate the MAP kinase pathway in the presence of the drugs enables them to resist the growth-inhibitory effects of the drug, leading to the observed ET-18-OCH3 insensitivity of the cells.

  11. Structural Basis for piRNA 2-O-methylated 3-end Recognition by Piwi PAZ (Piwi/Argonaute/Awille) Domains

    SciTech Connect

    Y Tian; D Simanshu; J Ma; D Patel

    2011-12-31

    Argonaute and Piwi proteins are key players in the RNA silencing pathway, with the former interacting with micro-RNAs (miRNAs) and siRNAs, whereas the latter targets piwi-interacting RNAs (piRNAs) that are 2'-O-methylated (2'-OCH{sub 3}) at their 3' ends. Germline-specific piRNAs and Piwi proteins play a critical role in genome defense against transposable elements, thereby protecting the genome against transposon-induced defects in gametogenesis and fertility. Humans contain four Piwi family proteins designated Hiwi1, Hiwi2, Hiwi3, and Hili. We report on the structures of Hili-PAZ (Piwi/Argonaute/Zwille) domain in the free state and Hiwi1 PAZ domain bound to self-complementary 14-mer RNAs (12-bp + 2-nt overhang) containing 2'-OCH{sub 3} and 2'-OH at their 3' ends. These structures explain the molecular basis underlying accommodation of the 2'-OCH{sub 3} group within a preformed Hiwi1 PAZ domain binding pocket, whose hydrophobic characteristics account for the preferential binding of 2'-OCH{sub 3} over 2'-OH 3' ends. These results contrast with the more restricted binding pocket for the human Ago1 PAZ domain, which exhibits a reverse order, with preferential binding of 2'-OH over 2'-OCH{sub 3} 3' ends.

  12. Structural basis for piRNA 2'-O-methylated 3'-end recognition by Piwi PAZ (Piwi/Argonaute/Zwille) domains.

    PubMed

    Tian, Yuan; Simanshu, Dhirendra K; Ma, Jin-Biao; Patel, Dinshaw J

    2011-01-18

    Argonaute and Piwi proteins are key players in the RNA silencing pathway, with the former interacting with micro-RNAs (miRNAs) and siRNAs, whereas the latter targets piwi-interacting RNAs (piRNAs) that are 2'-O-methylated (2(')-OCH(3)) at their 3' ends. Germline-specific piRNAs and Piwi proteins play a critical role in genome defense against transposable elements, thereby protecting the genome against transposon-induced defects in gametogenesis and fertility. Humans contain four Piwi family proteins designated Hiwi1, Hiwi2, Hiwi3, and Hili. We report on the structures of Hili-PAZ (Piwi/Argonaute/Zwille) domain in the free state and Hiwi1 PAZ domain bound to self-complementary 14-mer RNAs (12-bp + 2-nt overhang) containing 2(')-OCH(3) and 2'-OH at their 3' ends. These structures explain the molecular basis underlying accommodation of the 2(')-OCH(3) group within a preformed Hiwi1 PAZ domain binding pocket, whose hydrophobic characteristics account for the preferential binding of 2(')-OCH(3) over 2'-OH 3' ends. These results contrast with the more restricted binding pocket for the human Ago1 PAZ domain, which exhibits a reverse order, with preferential binding of 2'-OH over 2(')-OCH(3) 3' ends.

  13. Self-microemulsifying drug-delivery system for improved oral bioavailability of 20(S)-25-methoxyl-dammarane-3β, 12β, 20-triol: preparation and evaluation

    PubMed Central

    Cai, Shuang; Shi, Cai-Hong; Zhang, Xiangrong; Tang, Xiaojiao; Suo, Hao; Yang, Li; Zhao, Yuqing

    2014-01-01

    The objective of this study was to develop a self-microemulsifying drug delivery system (SMEDDS) to enhance the oral bioavailability of the poorly water-soluble compound 20(S)-25-methoxydammarane-3β;12β;20-triol (25-OCH3-PPD). Optimized SMEDDS formulations for 25-OCH3-PPD contained Cremophor® EL (50%) as the surfactant, glycerin (20%) as the cosurfactant, and Labrafil® M1944 (30%) as the oil. The SMEDDS were characterized by morphological observation and mean droplet size. The pharmacokinetics and bioavailability of the 25-OCH3-PPD suspension and SMEDDS were evaluated and compared in rats. The plasma concentrations of 25-OCH3-PPD and its main metabolite, 25-OH-PPD, were determined by ultra performance liquid chromatography-tandem mass spectrometry. The relative bioavailability of SMEDDS was dramatically enhanced by an average of 9.8-fold compared with the suspension. Improved solubility and lymphatic transport may contribute to this enhanced bioavailability. Our studies highlight the promise of SMEDDS for the delivery of 25-OCH3-PPD via the oral route. PMID:24611008

  14. Biological distinctions between juvenile nasopharyngeal angiofibroma and vascular malformation: an immunohistochemical study.

    PubMed

    Zhang, Mengjun; Sun, Xicai; Yu, Huapeng; Hu, Li; Wang, Dehui

    2011-10-01

    The exact nature of juvenile nasopharyngeal angiofibroma (JNA) is still in dispute. In recent years, the main controversy of its nature has focused on hemangioma and vascular malformation. In this study, the immunolocalization of vascular endothelial growth factor (VEGF), VEGF receptor-1/fms-like tyrosine kinase-1 (VEGFR-1/Flt-1), VEGF receptor-2/fetal liver kinase-1 (VEGFR-2/Flk-1), proliferating cell nuclear antigen (PCNA), and CD34 was investigated in 28 cases of JNA and 20 cases of orbital cavernous hemangiomas (OCH). The immunostaining levels of VEGF, Flt-1, and Flk-1 were higher and more frequent in vascular endothelial cells of JNA than those of OCH (p<0.05). The average microvessel density (MVD) marked by CD34 in JNA was (49.3 ± 9.1)/HPF (high power field), which was higher than OCH (29.1 ± 6.7)/HPF (p<0.05). Immunoreactivity of PCNA was localized in both endothelial and stromal cell components of JNA, but was predominantly seen in the stromal cells. However, no PCNA immunoreactivity was identified in any of the stromal and endothelial cells in cases of OCH. The immunostaining levels of CD34, VEGF, Flt-1, Flk-1, and PCNA in JNA were higher than those in OCH. These data support the view that JNA has biological characteristics of an angiogenic histogenetic tumor. In the future, anti-angiogenic therapy may represent a novel treatment strategy for JNA.

  15. Niobium alcoholate clusters with an octahedral arrangement of metal atoms: [K(CH3OH)4]2 [Nb6(OCH3)18] and [Na([18]crown-6)(C2H5OH)2]2 [Nb6(OC2H5)12(NCS)6].

    PubMed

    Flemming, Anke; Köckerling, Martin

    2009-01-01

    Complete exchange: [M(6)X(12)] type cluster compounds with an octahedral M(6) metal atom arrangement, which is completely surrounded by alcoholato ligands, were unknown until now. The first representatives are prepared containing a [Nb(6)(OR)(12)](4+) unit (R = CH(3) or C(2)H(5)). They are accessible at elevated temperatures from strongly basic alcoholate solutions of [Nb(6)Cl(12)](2+)-containing precursors. C gray, H white, K turquoise, Nb blue, O red.

  16. Microbial Antimony Biogeochemistry: Enzymes, Regulation, and Related Metabolic Pathways.

    PubMed

    Li, Jingxin; Wang, Qian; Oremland, Ronald S; Kulp, Thomas R; Rensing, Christopher; Wang, Gejiao

    2016-09-15

    Antimony (Sb) is a toxic metalloid that occurs widely at trace concentrations in soil, aquatic systems, and the atmosphere. Nowadays, with the development of its new industrial applications and the corresponding expansion of antimony mining activities, the phenomenon of antimony pollution has become an increasingly serious concern. In recent years, research interest in Sb has been growing and reflects a fundamental scientific concern regarding Sb in the environment. In this review, we summarize the recent research on bacterial antimony transformations, especially those regarding antimony uptake, efflux, antimonite oxidation, and antimonate reduction. We conclude that our current understanding of antimony biochemistry and biogeochemistry is roughly equivalent to where that of arsenic was some 20 years ago. This portends the possibility of future discoveries with regard to the ability of microorganisms to conserve energy for their growth from antimony redox reactions and the isolation of new species of "antimonotrophs."

  17. Microbial Antimony Biogeochemistry: Enzymes, Regulation, and Related Metabolic Pathways.

    PubMed

    Li, Jingxin; Wang, Qian; Oremland, Ronald S; Kulp, Thomas R; Rensing, Christopher; Wang, Gejiao

    2016-09-15

    Antimony (Sb) is a toxic metalloid that occurs widely at trace concentrations in soil, aquatic systems, and the atmosphere. Nowadays, with the development of its new industrial applications and the corresponding expansion of antimony mining activities, the phenomenon of antimony pollution has become an increasingly serious concern. In recent years, research interest in Sb has been growing and reflects a fundamental scientific concern regarding Sb in the environment. In this review, we summarize the recent research on bacterial antimony transformations, especially those regarding antimony uptake, efflux, antimonite oxidation, and antimonate reduction. We conclude that our current understanding of antimony biochemistry and biogeochemistry is roughly equivalent to where that of arsenic was some 20 years ago. This portends the possibility of future discoveries with regard to the ability of microorganisms to conserve energy for their growth from antimony redox reactions and the isolation of new species of "antimonotrophs." PMID:27342551

  18. Microbial antimony biogeochemistry: Enzymes, regulation, and related metabolic pathways

    USGS Publications Warehouse

    Li, Jingxin; Qian Wang,; Oremland, Ronald S.; Kulp, Thomas R.; Rensing, Christopher; Wang, Gejiao

    2016-01-01

    Antimony (Sb) is a toxic metalloid that occurs widely at trace concentrations in soil, aquatic systems, and the atmosphere. Nowadays, with the development of its new industrial applications and the corresponding expansion of antimony mining activities, the phenomenon of antimony pollution has become an increasingly serious concern. In recent years, research interest in Sb has been growing and reflects a fundamental scientific concern regarding Sb in the environment. In this review, we summarize the recent research on bacterial antimony transformations, especially those regarding antimony uptake, efflux, antimonite oxidation, and antimonate reduction. We conclude that our current understanding of antimony biochemistry and biogeochemistry is roughly equivalent to where that of arsenic was some 20 years ago. This portends the possibility of future discoveries with regard to the ability of microorganisms to conserve energy for their growth from antimony redox reactions and the isolation of new species of “antimonotrophs.”

  19. THE INTRACELLULAR LOCALIZATION OF INORGANIC CATIONS WITH POTASSIUM PYROANTIMONATE

    PubMed Central

    Tandler, Carlos J.; Libanati, César M.; Sanchis, Carlos A.

    1970-01-01

    Potassium pyroantimonate, when used as fixative (saturated or half-saturated, without addition of any conventional fixative) has been demonstrated to produce intracellular precipitates of the insoluble salts of calcium, magnesium, and sodium and to preserve the general cell morphology. In both animal and plant tissues, the electron-opaque antimonate precipitates were found deposited in the nucleus—as well as within the nucleolus—and in the cytoplasm, largely at the site of the ribonucleoprotein particles; the condensed chromatin appeared relatively free of precipitates. The inorganic cations are probably in a loosely bound state since they are not retained by conventional fixatives. The implications of this inorganic cation distribution in the intact cell are discussed in connection with their anionic counterparts, i.e., complexing of cations by fixed anionic charges and the coexistence of a large pool of inorganic orthophosphate anions in the nucleus and nucleolus. PMID:4935442

  20. Subcellular localization of calcium during Alpinia mutica Roxb. (Zingiberaceae) style movement.

    PubMed

    Luo, Yin Ling; Luo, Yan Jiang; Li, Qing Jun

    2011-04-01

    The subcellular localization of calcium in Alpinia mutica Roxb. during style movement was studied in two morphs. In the styles, Ca-antimonate precipitates (ppts) were principally located in apoplasts, with some minimal accumulation in the nucleus. At different movement, stages of movement, the ppts in the abaxial and adaxial sides changed, and no lateral gradient of ppts in the apoplast was established. The increase or decrease of ppts in the apoplast was not accompanied with equivalent changes in the cytoplasm. These results indicate that calcium could not affect the curvature by inhibiting cell elongation but may play a role in style movement by acting as a secondary messenger. EGTA-treatment affected style movement, providing further evidence supporting a role for calcium as a secondary messenger.

  1. Ochratoxin A displaces claudins from detergent resistant membrane microdomains.

    PubMed

    Lambert, Daniel; Padfield, Philip J; McLaughlin, John; Cannell, Stephanie; O'Neill, Catherine A

    2007-06-29

    Ochratoxin A (OchA) is a food-borne mycotoxin with multiple effects in vivo. Previously, we have demonstrated that the toxin can significantly impair the barrier function of the gut epithelial cell line, Caco-2. Barrier disruption involved loss of claudins 3 and 4, but not claudin 1 from the tight junction complex. In this study, we demonstrate for the first time, that OchA is able to remove claudins 3 and 4 from the detergent insoluble membrane microdomains associated with the tight junctions. However, cholesterol distribution within the microdomain was unaffected by the toxin. In addition, the thiol antioxidant, N-acetyl cysteine, preserved the microdomain localisation of claudins and also the barrier function of Caco-2 cells. This work suggests that OchA-mediated barrier toxicity is due to removal of claudins from detergent insoluble membrane microdomains. Moreover, loss of microdomain association may be due to oxidative events.

  2. 2011 North Plains research field 12-200 limited irrigation corn production study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The North Plains Water Conservation District started a water conservation project in 2010 on corn irrigation aimed at using just 12 inches of irrigation and producing 200 bu/ac of corn. This report is for 2011, the second year of the study, conducted at the North Plains Research Field (NPRF) in Ett...

  3. 78 FR 30243 - Airworthiness Directives; Eclipse Aerospace, Inc. Airplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-22

    ... revision or the ACS software update. Costs of Compliance We estimate that this proposed AD affects 81... software update. Authority for this Rulemaking Title 49 of the United States Code specifies the FAA's...) Update Aircraft Computer Software (ACS) (1) For airplanes equipped with Avio or Avio with ETT...

  4. Extrauterine epithelioid trophoblastic tumors presenting as primary lung carcinomas: morphologic and immunohistochemical features to resolve a diagnostic dilemma.

    PubMed

    Lewin, Sharyn N; Aghajanian, Carol; Moreira, Andre L; Soslow, Robert A

    2009-12-01

    Our objective was to describe the clinicopathologic features of epithelioid trophoblastic tumors (ETTs) in a series of patients who presented with elevated beta-human chorionic gonadotrophin (hCG) levels and extrauterine lesions resembling primary lung carcinomas. Clinical and pathologic materials were reviewed and Shih and Kurman's diagnostic criteria were applied. Three parous women (38, 49, and 34 y of age) with elevated beta-hCG levels had nondiagnostic gynecologic evaluations, including negative dilation and curettage specimens. Imaging revealed isolated pulmonary lesions, 2 to 8.5 cm in size, resembling primary lung carcinomas. Two patients received multiagent chemotherapy consisting of etoposide, methotrexate, dactinomycin, alternating with cisplatin and etoposide, and all underwent pulmonary resection. Histologically, the cytologic features, epithelioid growth pattern, and hyaline-like material simulated the appearance of nonsmall cell lung carcinoma, but overall, the histologic features along with the immunophenotype supported classification as ETT. Follow-up hysterectomy specimens were histologically normal. All 3 patients are alive and well. The rarity of ETT and its resemblance to squamous and pleomorphic carcinomas of lung have led to diagnostic difficulties. When reproductive-age women present with elevated beta-hCG levels, a pulmonary lesion, and no apparent intrauterine disease, primary pulmonary ETT should be considered. Correlating clinical indices with specific morphologic and immunohistochemical features can ensure diagnostic accuracy and appropriate treatment for favorable outcomes.

  5. 75 FR 45075 - Airworthiness Directives; Eclipse Aerospace, Inc. Model EA500 Airplanes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-02

    ... Register on July 9, 2010 (75 FR 39472), and applies to certain Eclipse Aerospace, Inc. (Eclipse) Model..., 000113 through 000115, 000120, and 000123 through 000124, that incorporate Avionics Upgrade to AVIO NG Configuration for ETT Configured Aircraft per any revision level of Eclipse SB 500-99-002.'' This...

  6. Linking Basic Skills to Entry-Level Electronics Test Technician Tasks. Instructional Resources. Assessments.

    ERIC Educational Resources Information Center

    Gaillard, Don; Mostaghel, Debbie

    This project first identified the specific mathematics, reading, writing, listening, and speaking skills required of an entry-level electronics testing technician (ETT), using a modified DACUM (Developing a Curriculum) occupational analysis process. This approach involves a panel of expert workers from the electronics industry who analyze and…

  7. The Cement Prosthesis-Like Spacer: An Intermediate Halt on the Road to Healing

    PubMed Central

    Ahmad, Sufian S.; Huber, Kim; Evangelopoulos, Dimitrios S.; Kleer, Barbara; Kohlhof, Hendrik; Schär, Michael; Eggli, Stefan; Kohl, Sandro

    2013-01-01

    Background. Periprosthetic infections remain a devastating problem in the field of joint arthroplasty. In the following study, the results of a two-stage treatment protocol for chronic periprosthetic infections using an intraoperatively molded cement prosthesis-like spacer (CPLS) are presented. Methods. Seventy-five patients with chronically infected knee prosthesis received a two-stage revision procedure with the newly developed CPLS between June 2006 and June 2011. Based on the microorganism involved, patients were grouped into either easy to treat (ETT) or difficult to treat (DTT) and treated accordingly. Range of motion (ROM) and the knee society score (KSS) were utilized for functional assessment. Results. Mean duration of the CPLS implant in the DTT group was 3.6 months (range 3–5 months) and in the ETT group 1.3 months (range 0.7–2.5 months). Reinfection rates of the final prosthesis were 9.6% in the ETT and 8.3% in the DTT group with no significant difference between both groups regarding ROM or KSS (P = 0.87, 0.64, resp.). Conclusion. The results show that ETT patients do not necessitate the same treatment protocol as DTT patients to achieve the same goal, emphasizing the need to differentiate between therapeutic regimes. We also highlight the feasibility of CLPS in two-stage protocols. PMID:24198728

  8. Changes in uncuffed endotracheal tube leak during laparoscopic inguinal herniorrhaphy in children.

    PubMed

    Noguchi, Akiko; Kuga, Kumiko; Tashiro, Naoki; Shimakawa, Yusuke; Shono, Takeshi; Hirakawa, Naomi; Sakaguchi, Yoshiro

    2016-08-01

    The present study was conducted to investigate changes in uncuffed endotracheal tube (ETT) leak during laparoscopic surgery. The study included 31 patients aged between 1 and 6 years scheduled for elective laparoscopic inguinal herniorrhaphy. Inspiratory and expiratory tidal volumes (TVi and TVe) were measured during mechanical ventilation, and ETT leak was calculated using the formula-ETT leak = (TVi - TVe)/TVi × 100 (%), assessed at the following time-points-5 min after the start of mechanical ventilation (T1, baseline), just before the start of surgery (T2), 5 min after the induction of pneumoperitoneum with 15° Trendelenburg tilt (T3), and at the end of surgery (T4). Additionally, leak pressure was assessed after successful tracheal intubation (T0, baseline) at T2, T3 and T4. Uncuffed ETT leak significantly decreased at T3 compared with T1 (baseline). Leak pressure significantly increased at T3 and T4 compared with T0 (baseline). Further studies are needed in order to determine whether the results are universal and associated with clinically significant outcomes. PMID:27193326

  9. 77 FR 68117 - Electric Transmission Texas, LLC; Notice of Petition for Declaratory Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-15

    ... Energy Regulatory Commission Electric Transmission Texas, LLC; Notice of Petition for Declaratory Order... Commission's (Commission) Rules of Practice and Procedure 18 CFR 385.207(a)(2), Electric Transmission Texas... Act (FPA) jurisdiction over (1) the transmission lines that ETT, an electric utility in the...

  10. Measurements of endotracheal tube cuff contact pressure using fibre Bragg gratings

    NASA Astrophysics Data System (ADS)

    Hernandez, F. U.; Correia, R.; Korposh, S.; Morgan, S. P.; Hayes-Gill, B. R.; James, S. W.; Evans, D.; Norris, A.

    2015-09-01

    An optical fibre Bragg grating (FBG) was used to measure local strain (due to contact pressure) at the interface of a cuffed endotracheal tube (ETT) tested in a tracheal model. The tracheal model consisted of a corrugated tube. Two FBG sensors written in a single optical fibre were attached to the outside wall of the cuff of the ETT. Intracuff endotracheal pressure was measured using a digital manometer, while the contact pressure between the model trachea and the ETT was measured using Flexiforce sensors. Changes in the Bragg wavelengths in response to the inflation of the cuff of the ETT, and concomitant pressure increase, were observed to be dependent on the location of the FBGs at the corrugations, i.e., the annular peaks and troughs of the corrugated tube. The performance of both contact pressure sensors FBG and Flexiforce suggests that FBG technology is better suited to this application as it allows the measurement of contact pressures on non-uniform surfaces such as in the tracheal model.

  11. Dobutamine stress echo is superior to exercise stress testing in achieving target heart rate among patients on beta blockers.

    PubMed

    Sabbath, Adam; Pack, Michael; Markiewicz, Richard; John, Jooby; Gaballa, Mohamed; Goldman, Steven; Thai, Hoang

    2005-01-01

    Published guidelines recommend continuing beta-adrenergic receptor blockade in patients undergoing stress testing. We evaluated the role of pharmacological versus exercise stress testing in achieving target heart rate (THR) among patients on beta-adrenergic blockade. We compared data from 140 patients who underwent dobutamine stress echo (DSE) and 143 patients who underwent exercise treadmill testing (ETT). In both groups, beta-adrenergic blocker was continued at the time of stress testing. Overall, patients undergoing DSE achieved THR more frequently than ETT. With beta-adrenergic blockade, DSE patients met THR more frequently than ETT patients (p < 0.001). Without beta-adrenergic blockade, there was no difference between either modality in achieving THR. In both DSE and ETT patients, absence of beta-adrenergic blockade increased the odds of achieving THR [odds ratio (OR): 2.46, p = 0.042 and OR: 7.44, p < 0.001, respectively]. Atropine use with DSE increased the odds of achieving THR (OR: 3.76, p = 0.006). In conclusion, pharmacological stress testing appears to be superior to exercise stress testing in achieving THR among patients on beta-adrenergic blockade.

  12. Coexisting epithelioid trophoblastic tumor and placental site trophoblastic tumor of the uterus following a term pregnancy: report of a case and review of literature

    PubMed Central

    Zhang, Xiaofei; zhou, Caiyun; Yu, Minghua; Chen, Xiaoduan

    2015-01-01

    Gestational trophoblastic neoplasms are a group of fetal trophoblastic tumors including choriocarcinomas, epithelioid trophoblastic tumors (ETTs), and placental site trophoblastic tumors (PSTTs). Mixed gestational trophoblastic neoplasms are extremely rare. The existence of mixed gestational trophoblastic neoplasms that were composed of choriocarcinoma and/or PSTT and/or ETT was also reported. Herein, we present a case of uterine mixed gestational trophoblastic neoplasm which is ETT admixed with PSTT, and reviewed 9 cases of mixed gestational trophoblastic neoplasms reported in English literature available. The most common combination was a choriocarcinoma admixed with an ETT and/or PSTT. Mixed gestational trophoblastic neoplasms present in women of reproductive age and rare in postmenopausal, Abnormal vaginal bleeding is the most common presenting symptom, serum β-HCG levels are elevated, mostly below 2500 mIU/ml, the tumor was limited to uterus in 7 cases, the rest of 3 with pulmonary metastases at the time of diagnosis. Mixed gestational trophoblastic neoplasms have more similar clinical features with intermediate trophoblastic tumors (ITTs). Total hysterectomy with lymph node dissection is recommended treatment for mixed gestational trophoblastic neoplasms, and chemotherapy should be used in patients with metastatic disease and with nonmetastatic disease who have adverse prognostic factors. PMID:26261623

  13. C---lH...O and O...H...O bonded intermediates in the dissociation of low energy methyl glycolate radical cations

    NASA Astrophysics Data System (ADS)

    Suh, Dennis; Kingsmill, Carol A.; Ruttink, Paul J. A.; Burgers, Peter C.; Terlouw, Johan K.

    1995-08-01

    Low energy methyl glycolate radical cations HOCH2C(=O)OCH3+, 1, abundantly lose HCO, yielding protonated methyl formate H---C(OH)OCH3+. Tandem mass spectrometry based experiments on 2H, 13C and 18O labelled isotopologues show that this loss is largely (about 75%) atom specific. Analysis of the atom connectivity in the product ions indicates that the reaction proceeds analogously to the loss of HCO and CH3CO from ionized acetol HOCH2C(=O)CH3+ and acetoin HOCH(CH3)C(=O)CH3+, respectively. The mechanism, it is proposed, involves isomerization of 1 to the key intermediate CH2=O... H---C(=O)OCH3+, an H-bridged ion-dipole complex of neutral formaldehyde and ionized methyl formate. Next, charge transfer takes place to produce CH3OC(H)=O...HC(H)=O+, an H-bridged ion-dipole complex of ionized formaldehyde and neutral methyl formate, followed by proton transfer to generate the products. Preliminary ab initio calculations executed at the UMP3/6-31G*//6-31G*+ZPVE level of theory are presented in support of this proposal. The non-specific loss of HCO from 1 (about 25%) is rationalized to occur via the same mechanism, but after communication with isomeric dimethyl carbonate ions CH3OC(=O)OCH3+, 2, via the O...H...O bonded intermediate [CH2=O...H...O=C---OCH3]+. The latter pathway is even more important in the formation of CH2OH+ ions from 1 which, it is shown, is not a simple bond cleavage reaction, but may involve consecutive or concerted losses of CH3 and CO2 from the above O...H...O bonded species. Ionized methyl lactate HOCH(CH3)C(=O)OCH3+, the higher homologue of 1, shows a unimolecular chemistry which is akin to that of 1.

  14. Complex formation between anisole and boron trifluoride: structural and binding properties.

    PubMed

    Lin, Tao; Zhang, Weijiang; Wang, Lichang

    2008-12-25

    The structures, energetics, and binding characteristics of complexes formed between anisole (C(6)H(5)OCH(3)) and boron trifluoride (BF(3)) were investigated using MP2 and B3LYP methods with 6-31+G(d,p) and 6-311+G(d,p) basis sets. Among the complexes with a 1:1 ratio of C(6)H(5)OCH(3) to BF(3), both B3LYP and MP2 methods predict the same structures and relative stability of the isomers; however, the B3LYP binding energies are smaller than the MP2 energies. Furthermore, the weaker the interaction, the greater the discrepancy in binding energy. The charge decomposition analysis (CDA) showed that there are two types of complexes: the Lewis acid-base adduct and the van der Waals complexes. The CDA results also illustrated that there is a significant donation from the oxygen lone pair electrons to the boron vacant orbital in the adduct. The van der Waals complexes were formed through the aromatic ring and BF(3) interaction or through the H and F interactions. The MP2 results showed that the formation of adduct at room temperature is thermodynamically favorable. Among the 1:2 C(6)H(5)OCH(3)-BF(3) complexes, the most stable structure consists of both the Lewis acid-base and van der Waals binding; i.e., one BF(3) binds with C(6)H(5)OCH(3) to form C(6)H(5)OCH(3) x BF(3) adduct, while the other BF(3) binds with this adduct through van der Waals interactions. The calculated binding energy of the 1:1 complex is close to the experimental heat of formation, which suggests that the 1:1 complexes are the most likely species in the C(6)H(5)OCH(3) and BF(3) mixture.

  15. Intracellular Triggering of Fas Aggregation and Recruitment of Apoptotic Molecules into Fas-enriched Rafts in Selective Tumor Cell Apoptosis

    PubMed Central

    Gajate, Consuelo; del Canto-Jañez, Esther; Acuña, A. Ulises; Amat-Guerri, Francisco; Geijo, Emilio; Santos-Beneit, Antonio M.; Veldman, Robert J.; Mollinedo, Faustino

    2004-01-01

    We have discovered a new and specific cell-killing mechanism mediated by the selective uptake of the antitumor drug 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3, Edelfosine) into lipid rafts of tumor cells, followed by its coaggregation with Fas death receptor (also known as APO-1 or CD95) and recruitment of apoptotic molecules into Fas-enriched rafts. Drug sensitivity was dependent on drug uptake and Fas expression, regardless of the presence of other major death receptors, such as tumor necrosis factor (TNF) receptor 1 or TNF-related apoptosis-inducing ligand R2/DR5 in the target cell. Drug microinjection experiments in Fas-deficient and Fas-transfected cells unable to incorporate exogenous ET-18-OCH3 demonstrated that Fas was intracellularly activated. Partial deletion of the Fas intracellular domain prevented apoptosis. Unlike normal lymphocytes, leukemic T cells incorporated ET-18-OCH3 into rafts coaggregating with Fas and underwent apoptosis. Fas-associated death domain protein, procaspase-8, procaspase-10, c-Jun amino-terminal kinase, and Bid were recruited into rafts, linking Fas and mitochondrial signaling routes. Clustering of rafts was necessary but not sufficient for ET-18-OCH3–mediated cell death, with Fas being required as the apoptosis trigger. ET-18-OCH3–mediated apoptosis did not require sphingomyelinase activation. Normal cells, including human and rat hepatocytes, did not incorporate ET-18-OCH3 and were spared. This mechanism represents the first selective activation of Fas in tumor cells. Our data set a framework for the development of more targeted therapies leading to intracellular Fas activation and recruitment of downstream signaling molecules into Fas-enriched rafts. PMID:15289504

  16. Protective effect of an aphrodisiac herb Tribulus terrestris Linn on cadmium-induced testicular damage

    PubMed Central

    Rajendar, B.; Bharavi, K.; Rao, G. S.; Kishore, P.V.S; Kumar, P. Ravi; Kumar, C.S.V Satish; Patel, T. Pankaj

    2011-01-01

    Aim: The aim of the present study was to investigate whether Tribulus terrestris Linn (TT) could protect the cadmium (Cd)-induced testicular tissue peroxidation in rats and to explore the underlying mechanism of the same. Materials and Methods: In vitro and in vivo studies were conducted to know the protective effect of ethanolic extract of TT (eTT) in Cd toxicity. In in vitro studies, total antioxidant and ferrous metal ion chelating activity of TT was studied. In vivo studies were conducted in rats. A total of 40 Wistar strain adult male rats were divided into four groups. Group 1 served as control, while group 2 to 4 received CdCl2 (3 mg/kg b. wt. s/c once a week). In addition to Cd, group 3 and 4 rats also received eTT (5 mg/kg b.wt. daily as oral gavage) and α-tocopherol (75 mg/kg daily by oral gavage), respectively. At the end of 6th week, all the rats were sacrificed and the separated testes were weighted and processed for estimation of tissue peroxidation markers, antioxidant markers, functional markers, and Cd concentration. The testes were also subjected to histopathological screening. Results: In in vitro studies, the percentage of metal ion chelating activity of 50 μg/ml of eTT and α-tocopherol were 2.76 and 9.39, respectively, and the antioxidant capacity of eTT was equivalent to 0.063 μg of α-tocopherol/μg of eTT. In in vivo studies, administration of Cd significantly reduced the absolute and relative testicular weight, antioxidant markers such as superoxide dismutase and glutathione, and functional markers such as LDH and ALP, along with significant increase in peroxidation markers such as malondialdehyde and protein carbonyls in testicular tissue. Testes of Cd only-treated group showed histological insults like necrotic changes in seminiferous tubules and interstitium, shrunken tubules with desquamated basal lamina, vacuolization and destruction of sertoli cells, and degenerating Leydig cells. This group also had higher Cd levels in testicular

  17. Nitroaliphatic difluoroformals

    DOEpatents

    Peters, Howard M.; Simon, Jr., Robert L.

    1978-01-01

    Nitroaliphatic difluoroformals of the formula RCH.sub.2 OCF.sub.2 OCH.sub.2 R' wherein R = FC(NO.sub.2).sub.2 -- and R' = F.sub.2 C(NO.sub.2)-- or CF.sub.3 --; or R = R' = CF.sub.3 OCH.sub.2 C(NO.sub.2).sub.2 --. The compounds are prepared in accordance with the following reaction: ##STR1## carried out at temperatures of from about 95.degree. C to about 150.degree. C. The compounds are especially useful as energetic plasticizers in explosive compositions.

  18. Development and evaluation of a treadmill-based exercise tolerance test in cardiac rehabilitation.

    PubMed

    Dunagan, Julie; Adams, Jenny; Cheng, Dunlei; Barton, Stephanie; Bigej-Cerqua, Janet; Mims, Lisa; Molden, Jennifer; Anderson, Valerie

    2013-07-01

    Cardiac rehabilitation exercise prescriptions should be based on exercise stress tests; however, limitations in performing stress tests in this setting typically force reliance on subjective measures like the Duke Activity Status Index (DASI). We developed and evaluated a treadmill-based exercise tolerance test (ETT) to provide objective physiologic measures without requiring additional equipment or insurance charges. The ETT is stopped when the patient's Borg scale rating of perceived exertion (RPE) reaches 15 or when any sign/symptom indicates risk of an adverse event. Outcomes of the study included reasons for stopping; maximum heart rate, systolic blood pressure, and rate pressure product; and adverse events. We tested equivalence to the DASI as requiring the 95% confidence interval for the mean difference between DASI and ETT metabolic equivalents (METs) to fall within the range (-1, 1). Among 502 consecutive cardiac rehabilitation patients, one suffered a panic attack; no other adverse events occurred. Most (80%) stopped because they reached an RPE of 15; the remaining 20% were stopped on indications that continuing risked an adverse event. Mean maximum systolic blood pressure, heart rate, and rate pressure product were significantly (P < 0.001) below thresholds of the American Association of Cardiovascular and Pulmonary Rehabilitation. Two patients' heart rates exceeded 150 beats per minute, but their rate pressure products remained below 36,000. The mean difference between DASI and ETT METs was -0.8 (-0.98, -0.65), indicating equivalence at our threshold. In conclusion, the ETT can be performed within cardiac rehabilitation, providing a functional capacity assessment equivalent to the DASI and objective physiologic measures for developing exercise prescriptions and measuring progress.

  19. On the '-1' scaling of air temperature spectra in atmospheric surface layer flows

    NASA Astrophysics Data System (ADS)

    Li, D.; Katul, G. G.; Gentine, P.

    2015-12-01

    The spectral properties of scalar turbulence at high wavenumbers have been extensively studied in turbulent flows, and existing theories explaining the k-5/3 scaling within the inertial subrange appear satisfactory at high Reynolds numbers. Equivalent theories for the low wavenumber range have been comparatively lacking because boundary conditions prohibit attainment of such universal behavior. A number of atmospheric surface layer (ASL) experiments reported a k-1 scaling in air temperature spectra ETT(k) at low wavenumbers but other experiments did not. Here, the occurrence of a k-1 scaling in ETT(k) in an idealized ASL flow across a wide range of atmospheric stability regimes is investigated theoretically and experimentally. Experiments reveal a k-1 scaling persisted across different atmospheric stability parameter values (ζ) ranging from mildly unstable to mildly stable conditions (-0.1< ζ < 0.2). As instability increases, the k-1 scaling vanishes. Based on a combined spectral and co-spectral budget models and upon using a Heisenberg eddy viscosity as a closure to the spectral flux transfer term, conditions promoting a k-1 scaling are identified. Existence of a k-1 scaling is shown to be primarily linked to an imbalance between the production and dissipation rates of half the temperature variance. The role of the imbalance between the production and dissipation rates of half the temperature variance in controlling the existence of a '-1' scaling suggests that the '-1' scaling in ETT(k) does not necessarily concur with the '-1' scaling in the spectra of longitudinal velocity Euu(k). This finding explains why some ASL experiments reported k-1 in Euu(k) but not ETT(k). It also differs from prior arguments derived from directional-dimensional analysis that lead to simultaneous k-1 scaling in Euu(k) and ETT(k) at low wavenumbers in a neutral ASL.

  20. Endotracheal tube cuff pressure before, during, and after fixed-wing air medical retrieval.

    PubMed

    Brendt, Peter; Schnekenburger, Marc; Paxton, Karen; Brown, Anthony; Mendis, Kumara

    2013-01-01

    Abstract Background. Increased endotracheal tube (ETT) cuff pressure is associated with compromised tracheal mucosal perfusion and injuries. No published data are available for Australia on pressures in the fixed-wing air medical retrieval setting. Objective. After introduction of a cuff pressure manometer (Mallinckrodt, Hennef, Germany) at the Royal Flying Doctor Service (RFDS) Base in Dubbo, New South Wales (NSW), Australia, we assessed the prevalence of increased cuff pressures before, during, and after air medical retrieval. Methods. This was a retrospective audit in 35 ventilated patients during fixed-wing retrievals by the RFDS in NSW, Australia. Explicit chart review of ventilated patients was performed for cuff pressures and changes during medical retrievals with pressurized aircrafts. Pearson correlation was calculated to determine the relation of ascent and ETT cuff pressure change from ground to flight level. Results. The mean (± standard deviation) of the first ETT cuff pressure measurement on the ground was 44 ± 20 cmH2O. Prior to retrieval in 11 patients, the ETT cuff pressure was >30 cmH2O and in 11 patients >50 cmH2O. After ascent to cruising altitude, the cuff pressure was >30 cmH2O in 22 patients and >50 cmH2O in eight patients. The cuff pressure was reduced 1) in 72% of cases prior to take off and 2) in 85% of cases during flight, and 3) after landing, the cuff pressure increased in 85% of cases. The correlation between ascent in cabin altitude and ETT cuff pressure was r = 0.3901, p = 0.0205. Conclusions. The high prevalence of excessive cuff pressures during air medical retrieval can be avoided by the use of cuff pressure manometers. Key words: cuff pressure; air medical retrieval; prehospital. PMID:23252881

  1. Relocation of earthquakes recorded by SIL network (Iceland) using empirical travel-time tables

    NASA Astrophysics Data System (ADS)

    Abril Lopez, C.; Gudmundsson, O.

    2015-12-01

    Three dimensional empirical travel time tables (ETT) are estimated for each station of the South Iceland Lowlands network (SIL) by interpolating travel-time observations mapped to the hypocenter of each event. ETT are used to relocate SIL database earthquakes using P- and S- arrival times. Results are compared with the initial locations from the SIL database and locations from local sub-networks in Iceland. The SIL database locations are estimated using 5 different 1-D velocity models for different regions. The arrival times were re-referenced to one single model (the SIL model). Minor discrepancies in archived travel-time reduction were identified and removed together with outliers. Travel times are decomposed into 1) the prediction of a 1-D reference velocity model; 2) deterministic variation of residuals from that 1-D model constructed by smoothing over a regional scale; and 3) a smaller-scale, stochastic component. The stochastic component is separated into a spatially incoherent part (noise) and a spatially coherent part assumed to correspond to remaining structural signal. The stochastic structural component is interpolated and summed to the other two travel time components in order to construct the ETTs. Relocation is computed with a non-linear grid-search algorithm. The resulting ETTs are useful for improving earthquake location where 1-D velocity models are frequently used and a fast secondary relocation process is required. Moreover, ETTs are "cleaned" travel times that can be used as input into 3D tomography, where the error estimation (incoherent component of residuals) serves as a useful guideline for data weighting.

  2. Endotracheal tube cuff pressure before, during, and after fixed-wing air medical retrieval.

    PubMed

    Brendt, Peter; Schnekenburger, Marc; Paxton, Karen; Brown, Anthony; Mendis, Kumara

    2013-01-01

    Abstract Background. Increased endotracheal tube (ETT) cuff pressure is associated with compromised tracheal mucosal perfusion and injuries. No published data are available for Australia on pressures in the fixed-wing air medical retrieval setting. Objective. After introduction of a cuff pressure manometer (Mallinckrodt, Hennef, Germany) at the Royal Flying Doctor Service (RFDS) Base in Dubbo, New South Wales (NSW), Australia, we assessed the prevalence of increased cuff pressures before, during, and after air medical retrieval. Methods. This was a retrospective audit in 35 ventilated patients during fixed-wing retrievals by the RFDS in NSW, Australia. Explicit chart review of ventilated patients was performed for cuff pressures and changes during medical retrievals with pressurized aircrafts. Pearson correlation was calculated to determine the relation of ascent and ETT cuff pressure change from ground to flight level. Results. The mean (± standard deviation) of the first ETT cuff pressure measurement on the ground was 44 ± 20 cmH2O. Prior to retrieval in 11 patients, the ETT cuff pressure was >30 cmH2O and in 11 patients >50 cmH2O. After ascent to cruising altitude, the cuff pressure was >30 cmH2O in 22 patients and >50 cmH2O in eight patients. The cuff pressure was reduced 1) in 72% of cases prior to take off and 2) in 85% of cases during flight, and 3) after landing, the cuff pressure increased in 85% of cases. The correlation between ascent in cabin altitude and ETT cuff pressure was r = 0.3901, p = 0.0205. Conclusions. The high prevalence of excessive cuff pressures during air medical retrieval can be avoided by the use of cuff pressure manometers. Key words: cuff pressure; air medical retrieval; prehospital.

  3. A prospective randomized control study comparing classic laryngeal mask airway with Guedel's airway for tracheal tube exchange and smooth extubation

    PubMed Central

    Jain, Shruti; Nazir, Nazia; Khan, Rashid M.; Ahmed, Syed M.

    2016-01-01

    Introduction: Extubation in deep plane of anesthesia followed by Guedel's oropharyngeal airway (OPA™) insertion is a routine method to avoid hemodynamic changes associated with tracheal extubation. Exchange of endotracheal tube (ETT) with Classic laryngeal mask airway (LMA™) prior to emergence from anesthesia also serves similar purpose. We had compared the hemodynamic changes involved during this ETT/LMA™ and ETT/OPA™ exchange technique. Material and Methods: This was a randomized prospective study on ASA I and 2 patients undergoing elective surgery under general anesthesia. These patients were randomly divided into two groups i.e. OPA group and LMA group of 50 patients each. Hemodynamic parameters i.e. systolic blood pressure (SBP) and heart rate (HR) were recorded during exchange of ETT with OPA™ or LMA™. Coughing / bucking during removal of OPA™ and LMA™, and presence of post operative sore throat for both the groups were also graded and recorded. Data within the groups have been analyzed using paired “t” test while those between the groups were analyzed using unpaired “t” test. Chi square test was used to analyze grades of coughing and post operative sore throat. Results: In both groups, hemodynamic parameters rose significantly as OPA™/LMA™ was placed (P < 0.05) and then started declining. Hemodynamic parameters continued to fall in LMA group after extubation. However in OPA group, hemodynamic parameters continued to rise even after extubation and declined only when OPA™ was removed. There was no statistical significant difference between the LMA and OPA group in respect to coughing and post operative sore throat. Conclusion: LMA™ is superior to OPA™ for exchange of ETT as it provides greater hemodynamic stability. PMID:27746550

  4. Better Hemodynamic Profile of Laryngeal Mask Airway Insertion Compared to Laryngoscopy and Tracheal Intubation

    PubMed Central

    Jarineshin, Hashem; Kashani, Saeed; Vatankhah, Majid; Abdulahzade Baghaee, Alireza; Sattari, Sahar; Fekrat, Fereydoon

    2015-01-01

    Background: Laryngoscopy and tracheal intubation can cause serious cardiovascular responses in patients such as hypertension, tachycardia, and arrhythmias. Alternative airway maintenance techniques may attenuate these hemodynamic stress responses. Objectives: This study aimed to compare the immediate hemodynamic effects of the insertion of laryngeal mask airway supreme (LMA-S) and classic (LMA-C) with laryngoscopy and Endotracheal Intubation (ETT). Patients and Methods: This study was a prospective, double-blind, and randomized clinical trial conducted on 150 patients aged 18 to 50 years with ASA I (American Society of Anesthesiologists), in the general operating room of Shahid Mohammadi hospital, Hormozgan university of medical sciences, Bandar Abbas, Iran. In the ETT group, endotracheal intubation was performed using the Macintosh laryngoscope; while for the LMA-C and LMA-S groups, LMA Classic and LMA Supreme were inserted, respectively. The induction and maintenance of anesthesia were similar in all patients. The hemodynamic parameters such as heart rate (HR), systolic blood pressure (SBP), and diastolic blood pressure (DBP) were measured before (baseline) and after induction of anesthesia at 4 different time points. The statistical analysis was done and P value less than 0.05 was considered significant. Results: Participants in all groups were similar in terms of gender, age, weight, height, and Mallampati class. The mean ± SD of SBPs (105.62 ± 12.12, 112.90 ± 12.2, and 112.48 ± 15.14 mm Hg, respectively for ETT, LMA-C, and LMA-S) and DBPs (64.64 ± 10.23, 73.78 ± 9.70, and 71.20 ± 12.27 mm Hg, respectively for ETT, LMA-C, and LMA-S) were significantly lower in the ETT group compared to LMA groups 5 minutes after device insertion (P < 0.01 for SBPs and P < 0.001 for DBPs); however these values were lower than the baseline values in all groups. There were no differences in the mean SBP and DBPs between the three groups at the other time points. The mean

  5. Role of Protein Glycosylation in Candida parapsilosis Cell Wall Integrity and Host Interaction

    PubMed Central

    Pérez-García, Luis A.; Csonka, Katalin; Flores-Carreón, Arturo; Estrada-Mata, Eine; Mellado-Mojica, Erika; Németh, Tibor; López-Ramírez, Luz A.; Toth, Renata; López, Mercedes G.; Vizler, Csaba; Marton, Annamaria; Tóth, Adél; Nosanchuk, Joshua D.; Gácser, Attila; Mora-Montes, Héctor M.

    2016-01-01

    Candida parapsilosis is an important, emerging opportunistic fungal pathogen. Highly mannosylated fungal cell wall proteins are initial contact points with host immune systems. In Candida albicans, Och1 is a Golgi α1,6-mannosyltransferase that plays a key role in the elaboration of the N-linked mannan outer chain. Here, we disrupted C. parapsilosis OCH1 to gain insights into the contribution of N-linked mannosylation to cell fitness and to interactions with immune cells. Loss of Och1 in C. parapsilosis resulted in cellular aggregation, failure of morphogenesis, enhanced susceptibility to cell wall perturbing agents and defects in wall composition. We removed the cell wall O-linked mannans by β-elimination, and assessed the relevance of mannans during interaction with human monocytes. Results indicated that O-linked mannans are important for IL-1β stimulation in a dectin-1 and TLR4-dependent pathway; whereas both, N- and O-linked mannans are equally important ligands for TNFα and IL-6 stimulation, but neither is involved in IL-10 production. Furthermore, mice infected with C. parapsilosis och1Δ null mutant cells had significantly lower fungal burdens compared to wild-type (WT)-challenged counterparts. Therefore, our data are the first to demonstrate that C. parapsilosis N- and O-linked mannans have different roles in host interactions than those reported for C. albicans. PMID:27014229

  6. Polymerizable 2(2-hydroxynaphthyl)2H-benzotriazole compounds

    DOEpatents

    Gomez, Peter M.; Neidlinger, Hermann H.

    1991-01-01

    Benzotriazole compounds having the formula: ##STR1## wherein R.sub.1 is H, Cl, or OCH.sub.3 ; R.sub.2 is a hydroxynaphthyl group; and R.sub.3 is a vinyl unsaturated polymerizable group. Homopolymers or copolymers thereof are effective as UV light stabilizers and absorbers.

  7. Adolescent Tobacco and Cannabis Use: Young Adult Outcomes from the Ontario Child Health Study

    ERIC Educational Resources Information Center

    Georgiades, Katholiki; Boyle, Michael H.

    2007-01-01

    Background: This study examines the longitudinal associations between adolescent tobacco and cannabis use and young adult functioning. Methods: Data for analysis come from the Ontario Child Health Study (OCHS), a prospective study of child health, psychiatric disorder and adolescent substance use in a general population sample that began in 1983,…

  8. Anomalous conformational behavior of poly(ethylene oxide) oligomers in aqueous solutions. A molecular dynamics study

    NASA Astrophysics Data System (ADS)

    Bedrov, Dmitry; Smith, Grant D.

    1998-11-01

    Molecular dynamics simulations of 1,2-dimethoxyethane (DME) CH3(OCH2CH2)OCH3 and diglyme CH3(OCH2CH2)2OCH3 in aqueous solution have been performed for several solution compositions. Conformational analysis of these systems shows that the g population of the O-C—C-O dihedral increases with increasing water content. For DME solutions, this increase is monotonic with a tendency to saturate in the extremely dilute (water-rich) regime. For diglyme solutions a distinct maximum in the g population of the O-C—C-O dihedral was observed at mole fraction Xdiglyme=0.03. More detailed analysis of the composition dependence of diglyme conformational populations reveals that the decrease in the O-C—C-O g population in extremely dilute solutions is due to a decrease in the tgt population of the C-O—C—C—O-C conformational triad. This in turn can be related to a decrease in a single conformer of diglyme, namely tgttgt. This conformer is unique in its nearly perfect antiparallel alignment of large triad dipoles. Finally, the anomalous conformational behavior of diglyme at extreme dilution is found to disappear at higher temperature.

  9. Reciprocal Cross-School Attraction in Domestic Educational Policy Borrowing: An Initial Conceptualization

    ERIC Educational Resources Information Center

    Barmeier, Henry

    2012-01-01

    This article presents a novel theoretical framework for the study of educational policy borrowing at the sub-national level. Prior theorizing on educational policy transfer, and on policy "borrowing" in particular, has focused on cross-national processes. In this article the author uses the existing cross-national models of Phillips and Ochs and…

  10. 40 CFR 63.62 - Redefinition of glycol ethers listed as hazardous air pollutants.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., diethylene glycol, and triethylene glycol R-(OCH2CH2)n-OR′. Where: n = 1, 2, or 3; R = alkyl C7 or less; or R = phenyl or alkyl substituted phenyl; R′= H or alkyl C7 or less; or OR′ consisting of carboxylic acid...

  11. 40 CFR 63.62 - Redefinition of glycol ethers listed as hazardous air pollutants.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., diethylene glycol, and triethylene glycol R-(OCH2CH2)n-OR′. Where: n = 1, 2, or 3; R = alkyl C7 or less; or R = phenyl or alkyl substituted phenyl; R′= H or alkyl C7 or less; or OR′ consisting of carboxylic acid...

  12. N-hypermannose glycosylation disruption enhances recombinant protein production by regulating secretory pathway and cell wall integrity in Saccharomyces cerevisiae.

    PubMed

    Tang, Hongting; Wang, Shenghuan; Wang, Jiajing; Song, Meihui; Xu, Mengyang; Zhang, Mengying; Shen, Yu; Hou, Jin; Bao, Xiaoming

    2016-01-01

    Saccharomyces cerevisiae is a robust host for heterologous protein expression. The efficient expression of cellulases in S. cerevisiae is important for the consolidated bioprocess that directly converts lignocellulose into valuable products. However, heterologous proteins are often N-hyperglycosylated in S. cerevisiae, which may affect protein activity. In this study, the expression of three heterologous proteins, β-glucosidase, endoglucanase and cellobiohydrolase, was found to be N-hyperglycosylated in S. cerevisiae. To block the formation of hypermannose glycan, these proteins were expressed in strains with deletions in key Golgi mannosyltransferases (Och1p, Mnn9p and Mnn1p), respectively. Their extracellular activities improved markedly in the OCH1 and MNN9 deletion strains. Interestingly, truncation of the N-hypermannose glycan did not increase the specific activity of these proteins, but improved the secretion yield. Further analysis showed OCH1 and MNN9 deletion up-regulated genes in the secretory pathway, such as protein folding and vesicular trafficking, but did not induce the unfolded protein response. The cell wall integrity was also affected by OCH1 and MNN9 deletion, which contributed to the release of secretory protein extracellularly. This study demonstrated that mannosyltransferases disruption improved protein secretion through up-regulating secretory pathway and affecting cell wall integrity and provided new insights into glycosylation engineering for protein secretion. PMID:27156860

  13. N-hypermannose glycosylation disruption enhances recombinant protein production by regulating secretory pathway and cell wall integrity in Saccharomyces cerevisiae

    PubMed Central

    Tang, Hongting; Wang, Shenghuan; Wang, Jiajing; Song, Meihui; Xu, Mengyang; Zhang, Mengying; Shen, Yu; Hou, Jin; Bao, Xiaoming

    2016-01-01

    Saccharomyces cerevisiae is a robust host for heterologous protein expression. The efficient expression of cellulases in S. cerevisiae is important for the consolidated bioprocess that directly converts lignocellulose into valuable products. However, heterologous proteins are often N-hyperglycosylated in S. cerevisiae, which may affect protein activity. In this study, the expression of three heterologous proteins, β-glucosidase, endoglucanase and cellobiohydrolase, was found to be N-hyperglycosylated in S. cerevisiae. To block the formation of hypermannose glycan, these proteins were expressed in strains with deletions in key Golgi mannosyltransferases (Och1p, Mnn9p and Mnn1p), respectively. Their extracellular activities improved markedly in the OCH1 and MNN9 deletion strains. Interestingly, truncation of the N-hypermannose glycan did not increase the specific activity of these proteins, but improved the secretion yield. Further analysis showed OCH1 and MNN9 deletion up-regulated genes in the secretory pathway, such as protein folding and vesicular trafficking, but did not induce the unfolded protein response. The cell wall integrity was also affected by OCH1 and MNN9 deletion, which contributed to the release of secretory protein extracellularly. This study demonstrated that mannosyltransferases disruption improved protein secretion through up-regulating secretory pathway and affecting cell wall integrity and provided new insights into glycosylation engineering for protein secretion. PMID:27156860

  14. Parental Expectations of the Swedish Municipal School of Arts

    ERIC Educational Resources Information Center

    Lilliedahl, Jonathan; Georgii-Hemming, Eva

    2009-01-01

    This article draws on a study designed to analyse parental expectations of the Swedish municipal school of arts (hereafter MSA) (in Swedish: kommunal musik- och kulturskola). The study is based on in-depth interviews conducted and informed by grounded theory. Although parental expectations are scarcely uniform, the study reveals a hope that the…

  15. Schools Reaching Out: An Introduction.

    ERIC Educational Resources Information Center

    Heleen, Owen

    1990-01-01

    Introduces an issue devoted to the Schools Reaching Out projects at David A. Ellis School in Roxbury (MA) and Adolph S. Ochs School in New York City. Projects attempt to link the schools with parents and their communities to promote the students' academic and social success. (DM)

  16. Polymerizable 2(2-hydroxynaphthyl)2H-benzotriazole compounds

    DOEpatents

    Gomez, P.M.; Neidlinger, H.H.

    1991-07-16

    Benzotriazole compounds having the formula: ##STR1## wherein R.sub.1 is H, Cl, or OCH.sub.3 ; R.sub.2 is a hydroxynaphthyl group; and R.sub.3 is a vinyl unsaturated polymerizable group. Homopolymers or copolymers thereof are effective as UV light stabilizers and absorbers.

  17. A Scientist or Salesman? Identity Construction through Referent Honorifics on a Japanese Shopping Channel Program

    ERIC Educational Resources Information Center

    Cook, Haruko Minegishi

    2013-01-01

    This paper explores how referent honorifics contribute to identity construction on a Japanese TV shopping channel program. Drawing on Ochs' twostep model of indexicality (1993, 1996) and Agah's proposal (1993) that honorifics are not directly linked to social status but index a "relative position within events of discursive…

  18. Co-Construction in Korean Interaction

    ERIC Educational Resources Information Center

    Ju, Hee

    2011-01-01

    This dissertation explores co-construction of a situated activity in a current unit by mainly focusing on hearers' actions. The "co-construction" involves a process of interaction in which speakers and hearers jointly construct the form and the meaning of ongoing utterances even when they disagree with each other (Jacoby & Ochs,…

  19. Social Networking in an Intensive English Program Classroom: A Language Socialization Perspective

    ERIC Educational Resources Information Center

    Reinhardt, Jonathon; Zander, Victoria

    2011-01-01

    This ongoing project seeks to investigate the impact, inside and outside of class, of instruction focused on developing learner awareness of social-networking site (SNS) use in an American Intensive English Program (IEP). With language socialization as an interpretative framework (Duff, in press; Ochs, 1988; Watson-Gegeo, 2004), the project uses a…

  20. Reactions of ruthenium hydrides with ethyl-vinyl sulfide.

    PubMed

    Dahcheh, Fatme; Stephan, Douglas W

    2014-03-01

    The Ru-hydride precursors (Im(OMe)2)(PPh3)2RuHCl () and (Me2Im(OMe)2)(PPh3)2RuHCl () reacted with ethyl-vinyl-sulfide to give ((MeOCH2CH2)C3H2N2(CH2CH(OMe))RuCl(PPh3)2 () and ((MeOCH2CH2)C3Me2N2(CH2CH(OMe))RuCl(PPh3)2 (), respectively. Dissolution of () in C6D6 prompts formation of ((MeOCH2CH2)C5H6N2(CHCH)RuCl(PPh3)2 (). The analogous reactions of the bis-carbene Ru-hydride precursors (Im(OMe)2)(IMes)(PPh3)RuHCl (), (Im(OMe)2)(SIMes)(PPh3)RuHCl () and (Im(OMe)2)(IMes-Cl2)(PPh3)RuHCl () gave ((MeOCH2CH2)C3H2N2(CHCH)RuCl(PPh3)(NHC) (NHC = IMes (), SIMes (), IMes-Cl2 (), respectively. The formation of compounds () and () is thought to go through an initial insertion of the vinyl-fragment into the Ru-H prompting subsequent C-H activation and loss of diethyl sulfide. This yields () and (), while subsequent loss of methanol yields () and (-). PMID:24441082

  1. A Voyage through the Radio Universe

    ERIC Educational Resources Information Center

    Spuck, Timothy

    2004-01-01

    Each year, professionals and amateurs alike make significant contributions to the field of astronomy. High school students can also conduct astronomy research. Since 1992, the Radio Astronomy Research Team from Oil City Area Senior High School (OCHS) in Oil City, Pennsylvania, has traveled each year to the National Radio Astronomy Observatory…

  2. Electron impact cross sections for surrogates of DNA sugar phosphate backbone

    NASA Astrophysics Data System (ADS)

    Bhowmik, Pooja; Joshipura, K. N.; Pandya, Siddharth

    2012-11-01

    Ionization and elastic cross sections by electron impact on H3PO4 and OP(OCH3)3 which are substitutes for the components of DNA phosphate group. We have employed the Complex Scattering Potential-ionization contribution (CSP-ic) formalism to calculate the cross sections in the energy range from ionization threshold to 2000 eV.

  3. Involvement of T-cell immunoregulation by ochnaflavone in therapeutic effect on fungal arthritis due to Candida albicans.

    PubMed

    Lee, Jue-Hee

    2011-07-01

    Arthritis due to pathogenic fungi is a serious disease causing rapid destruction of the joint. In the pathogenesis of arthritis, T lymphocytes are considered to be one of the major immune cells. In present study, we examined the T cell immunoregulatory effect by ochnaflavone (Och), a biflavonoid, on arthritis caused by Candida albicans that is the most commonly associated with fungal arthritis. To examine the effects of ochnaflavonon Candida albicans-caused septic arthritis, an emulsified mixture of C. albicans cell wall and complete Freund's adjuvant (CACW/CFA) was injected into BALB/c mice via hind footpad route on days -3, -2, and -1. On Day 0, Och at 1 or 2 mg/dose/time was intratraperitoneally given to mice with the swollen footpad every other day for 3 times. The footpad-edema was measured for 20 days. Results revealed that Och reduced the edema at all dose levels and furthermore, there was app. 45% reduction of the edema in animals given 2 mg-dose at the peak of septic arthritis (p < 0.05). This anti-arthritic effect was accompanied by the diminishing of the DTH (delayed type hypersensitivity) activity against the CACW and by the provoking of the dominant T helper 2 (Th2) type cytokines production (IL-4 and Il-10), which appeared to result in a suppression of T helper 1 cytokines (IFN-γ and IL-2). Besides the T cell immunoregulatory activity, Och inhibited T cells activation as evidenced by the IL-2 reduction from PMA/ionomycin-stimulated Jurkat cell line and in addition, the compound killed macrophages in a dose-dependent manner (p < 0.05). However, Och caused no hemolysis (p < 0.05). These data implicate that Och, which has anti-arthritic activity based on the Th2 dominance as well as macrophage removal, can be safely administered into the blood circulation for treatment of the arthritis caused by C. albicans. Thus, it can be concluded that Och would be an ideal immunologically evaluated agent for treating of Candida arthritis.

  4. Cyclo- and carbophosphazene-supported ligands for the assembly of heterometallic (Cu2+/Ca2+, Cu2+/Dy3+, Cu2+/Tb3+) complexes: synthesis, structure, and magnetism.

    PubMed

    Chandrasekhar, Vadapalli; Senapati, Tapas; Dey, Atanu; Das, Sourav; Kalisz, Marguerite; Clérac, Rodolphe

    2012-02-20

    The carbophosphazene and cyclophosphazene hydrazides, [{NC(N(CH(3))(2))}(2){NP{N(CH(3))NH(2)}(2)}] (1) and [N(3)P(3)(O(2)C(12)H(8))(2){N(CH(3))NH(2)}(2)] were condensed with o-vanillin to afford the multisite coordination ligands [{NC(N(CH(3))(2))}(2){NP{N(CH(3))N═CH-C(6)H(3)-(o-OH)(m-OCH(3))}(2)}] (2) and [{N(2)P(2)(O(2)C(12)H(8))(2)}{NP{N(CH(3))N═CH-C (6)H(3)-(o-OH)(m-OCH(3))}(2)}] (3), respectively. These ligands were used for the preparation of heterometallic complexes [{NC(N(CH(3))(2))}(2){NP{N(CH(3))N═CH-C(6)H(3)-(o-O)(m-OCH(3))}(2)}{CuCa(NO(3))(2)}] (4), [{NC(N(CH(3))(2))}(2){NP{N(CH(3))N═CH-C(6)H(3)-(o-O)(m-OCH(3))}(2)}{Cu(2)Ca(2)(NO(3))(4)}]·4H(2)O (5), [{NC(N(CH(3))(2))}(2){NP{N(CH(3))N═CH-C(6)H(3)-(o-O)(m-OCH(3))}(2)}{CuDy(NO(3))(4)}]·CH(3)COCH(3) (6), [{NP(O(2)C(12)H(8))}(2){NP{N(CH(3))N═CH-C(6)H(3)-(o-O)(m-OCH(3))}(2)}{CuDy(NO(3))(3)}] (7), and [{NP(O(2)C(12)H(8))}(2){NP{N(CH(3))N═CH-C(6)H(3)-(o-O)(m-OCH(3))}(2)}{CuTb(NO(3))(3)}] (8). The molecular structures of these compounds reveals that the ligands 2 and 3 possess dual coordination pockets which are used to specifically bind the transition metal ion and the alkaline earth/lanthanide metal ion; the Cu(2+)/Ca(2+), Cu(2+)/Tb(3+), and Cu(2+)/Dy(3+) pairs in these compounds are brought together by phenoxide and methoxy oxygen atoms. While 4, 6, 7, and 8 are dinuclear complexes, 5 is a tetranuclear complex. Detailed magnetic properties on 6-8 reveal that these compounds show weak couplings between the magnetic centers and magnetic anisotropy. However, the ac susceptibility experiments did not reveal any out of phase signal suggesting that in these compounds slow relaxation of magnetization is absent above 1.8 K. PMID:22320309

  5. Environmental risk assessment of hydrofluoroethers (HFEs).

    PubMed

    Tsai, Wen-Tien

    2005-03-17

    Hydrofluoroethers (HFEs) are being used as third generation replacements to chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and perfluorocarbons (PFCs) because of their nearly zero stratospheric ozone depletion and relatively low global warming potential. HFEs have been developed under commercial uses as cleaning solvents (incl., HFE-7500, C7F15OC2H5; HFE-7200, C4F9OC2H5; HFE-7100, C4F9CH3; HFE-7000, n-C3F7OCH3), blowing agents (incl., HFE-245mc, CF3CF2OCH3; HFC-356mec, CF3CHFCF2OCH3), refrigerants (incl., HFE-143a, CF3OCH3; HFE-134, CHF2OCHF2; HFE-245mc, CF3CF2OCH3), and dry etching agents in semiconductor manufacturing, (incl., HFE-227me, CF3OCHFCF3). From the environmental, ecological, and health points of view, it is important to understand their environmental risks for these HFEs from a diversity of commercial applications and industrial processes. This paper aims to introduce these HFEs with respect to physiochemical properties, commercial uses, and environmental hazards (i.e. global warming, photochemical potential, fire and explosion hazard, and environmental partition). Further, it addresses the updated data on the human toxicity, occupational exposure and potential health risk of commercial HFEs. It is concluded that there are few HFEs that still possess some environmental hazards, including global warming, flammability hazard and adverse effect of exposure. The partition coefficient for these HFEs has been estimated using the group contribution method; the values of logKow for commercial HFEs have been estimated to be below 3.5. PMID:15752850

  6. Functionalized arene-ruthenium(II) complexes: dangling vs. tethering side chain.

    PubMed

    Lastra-Barreira, Beatriz; Díez, Josefina; Crochet, Pascale; Fernández, Israel

    2013-04-21

    The reactivity of compounds [RuCl2(η(6)-C6H5OCH2CH2OH)(L)] (L = phosphine or phosphite) towards the chloride abstractor AgSbF6 has been investigated. Thus, the treatment of the triphenylphosphite complex [RuCl2(η(6)-C6H5OCH2CH2OH){P(OPh)3}] with one equivalent of AgSbF6 gave rise to the formation of the dinuclear dichloro-bridged species [{Ru(μ-Cl)(η(6)-C6H5OCH2CH2OH){P(OPh)3}}2](2+) as the hexafluoroantimonate salt. On the other hand, the triphenylphosphine analog [RuCl2(η(6)-C6H5OCH2CH2OH)(PPh3)] led, under the same experimental conditions, to the di-ruthenium derivative [{RuCl(η(6)-C6H5OCH2CH2OH)(PPh3)}2(μ-Cl)][SbF6] containing only one Cl-bridge. In sharp contrast, treatment of precursors [RuCl2(η(6)-C6H5CH2CH2CH2OH)(L)] (L = P(OPh)3, PPh3, P(OEt)3) with AgSbF6 resulted in the clean formation of the tethered compounds [RuCl{η(6):κ(1)(O)-C6H5CH2CH2CH2OH}(L)][SbF6]. The differences in reactivity observed have been rationalized by theoretical calculations.

  7. Gas-phase reactivity of metavanadate [VO3]- towards methanol and ethanol: experiment and theory.

    PubMed

    Waters, Tom; Wedd, Anthony G; O'Hair, Richard A J

    2007-01-01

    The gas-phase reactivity of the metavanadate anion [VO3]- towards methanol and ethanol was examined by a combination of ion-molecule reaction and isotope labelling experiments in a quadrupole ion-trap mass spectrometer. The experimental data were interpreted with the aid of density functional theory calculations. [VO3]- dehydrated methanol to eliminate water and form [VO2(eta2-OCH2)]-, which features an [eta2-C,O-OCH2]2- ligand formed by formal removal of two protons from methanol and which is isoelectronic with peroxide. [VO3]- reacted with ethanol in an analogous manner to form [VO2(eta2-OCHCH3)]-, as well as by loss of ethene to form [VO2(OH)2]-. The calculations predicted that important intermediates in these reactions were the hydroxo alkoxo anions [VO2(OH)(OCH2R)]- (R: H, CH3). These were predicted to undergo intramolecular hydrogen-atom transfer to form [VO(OH)2(eta1-OCHR)]- followed by eta1-O-->eta2-C,O rearrangements to form [VO(OH)2(eta2-OCHR)]-. The latter reacted further to eliminate water and generate the product [VO2(eta2-OCHR)]-. This major product observed for [VO3]- is markedly different from that observed previously for [NbO3]- containing the heavier Group 5 congener niobium. In that case, the major product of the reaction was an ion of stoichiometry [Nb, O3, H2]- arising from the formal dehydrogenation of methanol to formaldehyde. The origin of this difference was examined theoretically and attributed to the intermediate alkoxo anion [NbO2(OH)(OCH3)]- preferring hydride transfer to form [HNbO2(OH)]- with loss of formaldehyde. This contrasts with the hydrogen-atom-transfer pathway observed for [VO2(OH)(OCH3)]-. PMID:17661322

  8. Environmental risk assessment of hydrofluoroethers (HFEs).

    PubMed

    Tsai, Wen-Tien

    2005-03-17

    Hydrofluoroethers (HFEs) are being used as third generation replacements to chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs) and perfluorocarbons (PFCs) because of their nearly zero stratospheric ozone depletion and relatively low global warming potential. HFEs have been developed under commercial uses as cleaning solvents (incl., HFE-7500, C7F15OC2H5; HFE-7200, C4F9OC2H5; HFE-7100, C4F9CH3; HFE-7000, n-C3F7OCH3), blowing agents (incl., HFE-245mc, CF3CF2OCH3; HFC-356mec, CF3CHFCF2OCH3), refrigerants (incl., HFE-143a, CF3OCH3; HFE-134, CHF2OCHF2; HFE-245mc, CF3CF2OCH3), and dry etching agents in semiconductor manufacturing, (incl., HFE-227me, CF3OCHFCF3). From the environmental, ecological, and health points of view, it is important to understand their environmental risks for these HFEs from a diversity of commercial applications and industrial processes. This paper aims to introduce these HFEs with respect to physiochemical properties, commercial uses, and environmental hazards (i.e. global warming, photochemical potential, fire and explosion hazard, and environmental partition). Further, it addresses the updated data on the human toxicity, occupational exposure and potential health risk of commercial HFEs. It is concluded that there are few HFEs that still possess some environmental hazards, including global warming, flammability hazard and adverse effect of exposure. The partition coefficient for these HFEs has been estimated using the group contribution method; the values of logKow for commercial HFEs have been estimated to be below 3.5.

  9. Multiple bonds between transition metals and main-group elements. 73. Synthetic routes to rhenium(V) alkyl and rhenium(VII) alkylidyne complexes. X-ray crystal structures of (. eta. sup 5 -C sub 5 Me sub 5 )Re( double bond O)(CH sub 3 )(CH sub 2 C(CH sub 3 ) sub 3 ) and (. eta. sup 5 -C sub 5 Me sub 5 )(Br) sub 3 Re triple bond CC(CH sub 3 ) sub 3

    SciTech Connect

    Herrmann, W.A.; Felixberger, J.K.; Anwander, R.; Herdtweck, E.; Kiprof, P.; Riede, J. )

    1990-05-01

    Dialkyloxo({eta}{sup 5}pentamethylcyclopentadienyl)rhenium(V) complexes ({eta}{sup 5}-C{sub 5}Me{sub 5})Re({double bond}O)(CH{sub 3})R{prime}(R{prime} = C{sub 2}H{sub 5}, CH{sub 2}Si(CH{sub 3}){sub 3}, CH{sub 2}C(CH{sub 3}){sub 3}), 1c-e, have become accessible through alkylation of ({eta}{sup 5}-C{sub 5}Me{sub 5})Re({double bond}O)(Cl)(CH{sub 3}) (7) with R{prime}MgCl. 1c-e are the first rhenium complexes containing different alkyl ligands. The neopentyl derivative 1e (R{prime} = CH{sub 2}C(CH{sub 3}){sub 3}) crystallizes in the orthorhombic space group Pbca with a = 960.7 (2), b = 2.844.5 (4), c = 1,260.7 (2) pm, and Z = 8. The X-ray crystal structure was refined to R{sub W} = 3.9%. The chiral molecule shows a distorted tetrahedral geometry around the rhenium center. The tribromide 3b has been structurally characterized. Brown crystals of 3b belong to space group P2{sub 1}/c with unit cell dimensions a = 1,311.5 (2), b = 723.0 (1), c = 1,901.6 (2) pm, {beta} = 92.68 (1){degree}, and Z = 4. The structure exhibits a four-legged piano stool geometry with no trans influence of the neopentylidyne ligand to the bromine atom.

  10. Endotracheal tube fires during carbon dioxide laser surgery on the larynx--a case report.

    PubMed

    Kuo, C H; Tan, P H; Chen, J J; Peng, C H; Lee, C C; Chung, H C; Tseng, C K

    2001-03-01

    Endotracheal tube (ETT) fire is a catastrophic disaster that may occur during laser surgery of the upper airway. Several means are available for protection of polyvinyl chloride (PVC) tube from fire, but they are not perfect in prevention of fires caused by laser beam. The PVC tube is hazardous for carbon dioxide (CO2) laser surgery if it is not well wrapped with metallized foil tape. We report a case that a PVC ETT wrapped with aluminum foil ignited during CO2 laser surgery of the larynx. In this report, we emphasize the shaft of the PVC tube must be completely wrapped with aluminum foil to prevent exposure of any surface if it is used in CO2 laser surgery of the upper aero digestive tract. PMID:11407297

  11. Airway Complications during and after General Anesthesia: A Comparison, Systematic Review and Meta-Analysis of Using Flexible Laryngeal Mask Airways and Endotracheal Tubes

    PubMed Central

    Xu, Rui; Lian, Ying; Li, Wen Xian

    2016-01-01

    Objective Flexible laryngeal mask airways (FLMAs) have been widely used in thyroidectomy as well as cleft palate, nasal, upper chest, head and neck oncoplastic surgeries. This systematic review aims to compare the incidence of airway complications that occur during and after general anesthesia when using the FLMA and endotracheal intubation (ETT). We performed a quantitative meta-analysis of the results of randomized trials. Methods A comprehensive search of the PubMed, Embase and Cochrane Library databases was conducted using the key words "flexible laryngeal mask airway" and "endotracheal intubation". Only prospective randomized controlled trials (RCTs) that compared the FLMA and ETT were included. The relative risks (RRs) and the corresponding 95% confidence intervals (95% CIs) were calculated using a quality effects model in MetaXL 1.3 software to analyze the outcome data. Results Ten RCTs were included in this meta-analysis. There were no significant differences between the FLMA and ETT groups in the incidence of difficulty in positioning the airway [RR = 1.75, 95% CI = (0.70–4.40)]; the occurrence of sore throat at one hour and 24 hours postoperative [RR = 0.90, 95% CI = (0.13–6.18) and RR = 0.95, 95% CI = (0.81–1.13), respectively]; laryngospasms [RR = 0.58, 95% CI = (0.27–1.23)]; airway displacement [RR = 2.88, 95% CI = (0.58–14.33)]; aspiration [RR = 0.76, 95% CI = (0.06–8.88)]; or laryngotracheal soiling [RR = 0.34, 95% CI = (0.10–1.06)]. Patients treated with the FLMA had a lower incidence of hoarseness [RR = 0.31, 95% CI = (0.15–0.62)]; coughing [RR = 0.28, 95% CI = (0.15–0.51)] during recovery in the postanesthesia care unit (PACU); and oxygen desaturation [RR = 0.43, 95% CI = (0.26–0.72)] than did patients treated with ETT. However, the incidence of partial upper airway obstruction in FLMA patients was significantly greater than it was for ETT patients [RR = 4.01, 95% CI = (1.44–11.18)]. Conclusion This systematic review showed

  12. Children's implicit learning of graphotactic and morphological regularities.

    PubMed

    Pacton, Sébastien; Fayol, Michel; Perruchet, Pierre

    2005-01-01

    In French, the transcription of the same sound can be guided by both probabilistic graphotactic constraints (e.g., /epsilon t/ is more often transcribed ette after -v than after -f) and morphological constraints (e.g., /epsilon t/ is always transcribed ette when used as a diminutive suffix). Three experiments showed that pseudo-word spellings of 8-to 11-year-old children and adults were influenced by both types of constraints. The influence of graphotactic regularities persisted when reliance on morphological rules was possible, without any falling off as a function of age. This suggests that rules are not abstracted, even after massive amounts of exposure to a rule-based material. These results can be accounted for by a statistical model of implicit learning. PMID:15784085

  13. Survival time of endodontically treated teeth: a 7-year retrospective clinical study

    NASA Astrophysics Data System (ADS)

    Baldea, Bogdan; Canjau, Silvana; Popescu, Dragos; Tudor, Anca; Todea, Carmen

    2014-01-01

    The aim of this retrospective clinical study was to examine the survival time of endodontically treated teeth (ETT) and the factors that may influence the failure risk, over a period of up to 7 years. The files of 67 patients that received metal free post and core restorations using a standardized technique were analyzed. The survival probability was assessed using Kaplan-Meyer analysis and Log Rank (Matel-Cox). Cox regression was used to assess the risk of failure and to identify possible covariates. The average survival time of the ETT was 6.6 Years. The cumulative failure rate was 5.82% for all type of the restored endodontically treated teeth. The main failure type was encountered in the cervical area of the teeth, and due to the extensive hard tissue loss, the teeth were extracted.

  14. [Successful Use of the i-gel and Dexmedetomidine for Tracheal Resection and Construction Surgery in a Patient with Severe Tracheal Stenosis].

    PubMed

    Kashii, Tomoko; Nabatame, Maki; Okura, Nahomi; Fujinaga, Ayumi; Namoto, Kazuko; Mori, Masafumi; Tsujimura, Shigehisa

    2016-04-01

    A 51-year-old man, 170 cm, 86 kg, was diagnosed with a tracheal tumor existing just below the glottis occupying more than 80% of his tracheal lumen, and was scheduled for tracheal resection and construction. The patient had a strider due to the severe tracheal stenosis. We could insert i-gel easily under dexmedetomidine sedation. After successful i-gel insertion, tracheotomy and endotracheal intubation were performed. Until ETT insertion, the patient maintained spontaneous respiration without any hypoxic event. Followed by ETT insertion, tracheal resection and construction were performed under general anesthesia. After the operation, the patient was extubated and transferred to the intensive care unit (ICU), where he was given DEX infusion to keep the tracheal anastomosis immobilized. There was no serious complication during the perioparative period. PMID:27188107

  15. Ultrasonography of Extravaginal Testicular Torsion in Neonates

    PubMed Central

    Bombiński, Przemysław; Warchoł, Stanisław; Brzewski, Michał; Majkowska, Zofia; Dudek-Warchoł, Teresa; Żerańska, Maria; Panek, Małgorzata; Drop, Magdalena

    2016-01-01

    Summary Background Extravaginal testicular torsion (ETT), also called prenatal or perinatal, occurs prenatally and is present at birth or appears within the first month of life. It has different etiology than intravaginal torsion, which appears later in life. Testicular torsion must be taken into consideration in differential diagnosis of acute scrotum and should be confirmed or ruled out at first diagnostic step. Ultrasonography is a basic imaging modality, however diagnostic pitfalls are still possible. There is still wide discussion concerning management of ETT, which varies from immediate orchiectomy to conservative treatment resulting in testicle atrophy. Material/Methods In this article we present ultrasonographic spectrum of ETT in neonates, which were diagnosed and treated in our hospital during the last 8 years (2008–2015), in correlation with clinical and intraoperative findings. Results Thirteen neonates with ETT were enrolled in the study – 11 patients with a single testicle affected and 2 patients with bilateral testicular torsion. Most common signs on clinical examination were: hardened and enlarged testicle and discoloration of the scrotum. Most common ultrasonographic signs were: abnormal size or echostructure of the affected testicle and absence of the blood flow in Doppler ultrasonography. In 3 patients ultrasound elastography was performed, which appeared very useful in testicle structure assessment. Conclusions Testicular torsion may concern boys even in the perinatal period. Ultrasonographic picture of acute scrotum in young boys may be confused. Coexistence of the abnormal size or echostructure of the torsed testicle with absence of the blood flow in Doppler ultrasonography appear as very specific but late ultrasonographic sings. Ultrasound elastography may be a very useful tool for visualisation of a very common clinical sign – hardening of the necrotic testicle. PMID:27757176

  16. Respiratory and hemodynamic outcomes following exchange extubation with laryngeal mask airway as compared to traditional awake extubation

    PubMed Central

    Suppiah, Ramanathan Kannan; Rajan, Sunil; Paul, Jerry; Kumar, Lakshmi

    2016-01-01

    Background: Traditional awake extubation leads to respiratory complications and hemodynamic response which are detrimental in neurosurgery, ENT surgery and patients with comorbidities. Aims: The primary objective was to compare the respiratory complications and hemodynamic stress response between traditional awake extubation of a endotracheal tube (ETT) and that following exchange extubation of ETT by using a laryngeal mask airway (LMA). Settings and Design: This prospective randomized study was conducted in a Tertiary Care Centre in 60 American Society of Anesthesiologists I and II patients coming for general surgery. Materials and Methods: Patients were randomized by permuted blocks into traditional awake extubation group and exchange extubation group. At the end of surgery in traditional group, awake extubation of ETT was done. In exchange group, 0.3 mg/kg propofol was administered, and the ETT was exchanged for a LMA. Awake extubation of LMA was then performed. Respiratory complications such as bucking, coughing, desaturation and the need for airway maneuvers and hemodynamic response were noted in both groups. Analysis Tools: Chi-square test, independent sample t- and paired t-tests were used as applicable. Results: Incidence of respiratory complication was 93.3% in traditional extubation while it was only 36.7% in exchange extubation group (P < 0.001). Hemodynamic response measured immediately at extubation in terms of heart rate, systolic blood pressure (BP), diastolic BP, mean arterial pressure, and rate pressure product were all significantly lesser in exchange group when compared to traditional extubation. Conclusion: Exchange extubation with LMA decreases respiratory complications and hemodynamic stress response when compared to traditional awake extubation. PMID:27212749

  17. The changes of endotracheal tube cuff pressure by the position changes from supine to prone and the flexion and extension of head

    PubMed Central

    Kim, Deokkyu; Jeon, Byeongdo; Son, Ji-Seon; Lee, Jun-Rae; Ko, Seonghoon

    2015-01-01

    Background The proper cuff pressure is important to prevent complications related to the endotracheal tube (ETT). We evaluated the change in ETT cuff pressure by changing the position from supine to prone without head movement. Methods Fifty-five patients were enrolled and scheduled for lumbar spine surgery. Neutral angle, which was the angle on the mandibular angle between the neck midline and mandibular inferior border, was measured. The initial neutral pressure of the ETT cuff was measured, and the cuff pressure was subsequently adjusted to 26 cmH2O. Flexed or extended angles and cuff pressure were measured in both supine and prone positions, when the patient's head was flexed or extended. Initial neutral pressure in prone was compared with adjusted neutral pressure (26 cmH2O) in supine. Flexed and extended pressure were compared with adjusted neutral pressure in supine or prone, respectively. Results There were no differences between supine and prone position for neutral, flexed, and extended angles. The initial neutral pressure increased after changing position from supine to prone (26.0 vs. 31.5 ± 5.9 cmH2O, P < 0.001). Flexed and extended pressure in supine were increased to 38.7 ± 6.7 (P < 0.001) and 26.7 ± 4.7 cmH2O (not statistically significant) than the adjusted neutral pressure. Flexed and extended pressure in prone were increased to 40.5 ± 8.8 (P < 0.001) and 29.9 ± 8.7 cmH2O (P = 0.002) than the adjusted neutral pressure. Conclusions The position change from supine to prone without head movement can cause a change in ETT cuff pressure. PMID:25664152

  18. A randomized control study comparing the pharyngolaryngeal morbidity of laryngeal mask airway versus endotracheal tube

    PubMed Central

    Venugopal, A.; Jacob, Ron Mathew; Koshy, Rachel Cherian

    2016-01-01

    Introduction: Endotracheal tube (ETT) has been associated with various pharyngolaryngeal morbidities (PLMs) following general anesthesia (GA). Laryngeal mask airway (LMA), currently the most commonly used supraglottic airway device, has several advantageous over the ETT but has been associated with varying results of PLM. The aim of our study was to compare the PLM between them and to know whether LMA is a better alternative. Materials and Methods: One hundred and seventy American Society of Anesthesiologists Grades 1 and 2 women scheduled for elective mastectomy were included in the study, 85 each in either group, E Group (intubated with ETT) and L Group (using LMA) on a random basis. All patients received GA with controlled ventilation using a muscle relaxant. PLMs such as hoarseness, pain on phonation, sore throat, and difficulty in swallowing were documented by an interview done postoperatively. Peroperative parameters such as intubation attempts, trauma during airway device insertion, and intraoperative incidents were also analyzed. A sample size of 85 patients in each group was calculated in order to achieve a study power of 0.8 and alpha level was taken as 0.05. Data were analyzed using SPSS version 16 using Chi-square test, Mann–Whitney U-test and Fisher's exact test were used as nonparametric tests. A two-tailed P< 0.05 was considered significant. Results: Patients in E Group had statistically significant increased incidence of a sore throat and voice complaints whereas L Group showed a statistically significant increase of swallowing problems. There was also a significant correlation between traumatic insertion and sore throat, pain on swallowing in the L Group, which could be due to direct trauma. Conclusions: ETT was associated with an increased incidence of voice problems and sore throat whereas LMA had an increased incidence of dysphagia and odynophagia. Use of LMA changes the pharyngolaryngeal profile to a more acceptable one. PMID:27212745

  19. Unusual room temperature activation of 1,2-dialkoxyalkanes by niobium and tantalum pentachlorides.

    PubMed

    Marchetti, Fabio; Pampaloni, Guido; Zacchini, Stefano

    2008-12-28

    The outcome of the reactions of MCl(5) (M = Nb, 1a; M = Ta, 1b) with 1,2-dialkoxyalkanes [i.e. MeO(CH(2))(2)OMe (dme), EtO(CH(2))(2)OEt, MeOCH(2)CH(Me)OMe, MeO(CH(2))(2)OCH(2)Cl, MeO(CH(2))(2)O(CH(2))(2)OMe (diglyme)] depends strictly on the stoichiometry. In the 1 : 1 molar ratio reactions, single C-O bond cleavage occurs, resulting in formation of alkyl chloride and of the complexes [upper bond 1 start]MCl(4)[O(R)CH(R')CH(2)O][upper bond 1 end] [M = Nb, R = Me, R' = H, 3a; M = Ta, R = Me, R' = H, 3b; M = Nb, R = Et, R' = H, 5; M = Nb, R = R' = Me, 6; M = Nb, R = CH(2)Cl, R' = H, 7; M = Nb, R = (CH(2))(2)O(Me)NbCl(5), R' = H, 8], which have been characterized spectroscopically. Moreover, minor amounts of the oxo-bridged adducts MOCl(3)(dme)MCl(5) (M = Nb, 4a; M = Ta, 4b) have been isolated in the reactions involving dme. On the other hand, compounds react with two (or more) equivalents of dme mainly via a multiple C-O bond cleavage process, affording MOCl(3)(dme) (M = Nb, 2a; M = Ta, 2b), 1,4-dioxane and methyl chloride. The oxychloride compounds MOCl(3) (M = Nb, 11a; M = Ta, 11b) have been efficiently obtained by addition of TiCl(4) to 2. Compound 2a is reduced in high yield to the Nb(III) species NbCl(3)(dme), 12, upon treatment with SnBu(3)H. The oxychloride NbOCl(3)(diglyme), 9, 1,4-dioxane, CH(3)Cl and the hexachloroniobate salt [MeOCH(2)CH(2)OCH(2)CH(2)O(H)Me][NbCl(6)], 10, have been identified as products of the reaction of 1a with two equivalents of diglyme. The 1 : 2 molar ratio reaction of 1a with MeOCH(2)CH(Me)OMe gives 2,5-dimethyl-1,4-dioxane. Compound 1a reacts with two equivalents of EtO(CH(2))(2)OEt or MeO(CH(2))(2)OCH(2)Cl yielding Cl(CH(2))(2)OCH(2)CH(3) or O(CH(2)Cl)(2) and diglyme, respectively, but not dioxane, suggesting that fragmentation pathways different from that found for dme are operating. The X-ray molecular structures of 4a, 4b and 10 have been determined.

  20. Unusual room temperature activation of 1,2-dialkoxyalkanes by niobium and tantalum pentachlorides.

    PubMed

    Marchetti, Fabio; Pampaloni, Guido; Zacchini, Stefano

    2008-12-28

    The outcome of the reactions of MCl(5) (M = Nb, 1a; M = Ta, 1b) with 1,2-dialkoxyalkanes [i.e. MeO(CH(2))(2)OMe (dme), EtO(CH(2))(2)OEt, MeOCH(2)CH(Me)OMe, MeO(CH(2))(2)OCH(2)Cl, MeO(CH(2))(2)O(CH(2))(2)OMe (diglyme)] depends strictly on the stoichiometry. In the 1 : 1 molar ratio reactions, single C-O bond cleavage occurs, resulting in formation of alkyl chloride and of the complexes [upper bond 1 start]MCl(4)[O(R)CH(R')CH(2)O][upper bond 1 end] [M = Nb, R = Me, R' = H, 3a; M = Ta, R = Me, R' = H, 3b; M = Nb, R = Et, R' = H, 5; M = Nb, R = R' = Me, 6; M = Nb, R = CH(2)Cl, R' = H, 7; M = Nb, R = (CH(2))(2)O(Me)NbCl(5), R' = H, 8], which have been characterized spectroscopically. Moreover, minor amounts of the oxo-bridged adducts MOCl(3)(dme)MCl(5) (M = Nb, 4a; M = Ta, 4b) have been isolated in the reactions involving dme. On the other hand, compounds react with two (or more) equivalents of dme mainly via a multiple C-O bond cleavage process, affording MOCl(3)(dme) (M = Nb, 2a; M = Ta, 2b), 1,4-dioxane and methyl chloride. The oxychloride compounds MOCl(3) (M = Nb, 11a; M = Ta, 11b) have been efficiently obtained by addition of TiCl(4) to 2. Compound 2a is reduced in high yield to the Nb(III) species NbCl(3)(dme), 12, upon treatment with SnBu(3)H. The oxychloride NbOCl(3)(diglyme), 9, 1,4-dioxane, CH(3)Cl and the hexachloroniobate salt [MeOCH(2)CH(2)OCH(2)CH(2)O(H)Me][NbCl(6)], 10, have been identified as products of the reaction of 1a with two equivalents of diglyme. The 1 : 2 molar ratio reaction of 1a with MeOCH(2)CH(Me)OMe gives 2,5-dimethyl-1,4-dioxane. Compound 1a reacts with two equivalents of EtO(CH(2))(2)OEt or MeO(CH(2))(2)OCH(2)Cl yielding Cl(CH(2))(2)OCH(2)CH(3) or O(CH(2)Cl)(2) and diglyme, respectively, but not dioxane, suggesting that fragmentation pathways different from that found for dme are operating. The X-ray molecular structures of 4a, 4b and 10 have been determined. PMID:19050789

  1. Strain induced Z{sub 2} topological insulating state of β-As{sub 2}Te{sub 3}

    SciTech Connect

    Pal, Koushik; Waghmare, Umesh V.

    2014-08-11

    Topological insulators are non-trivial quantum states of matter which exhibit a gap in the electronic structure of their bulk form, but a gapless metallic electronic spectrum at the surface. Here, we predict a uniaxial strain induced electronic topological transition (ETT) from a band to topological insulating state in the rhombohedral phase (space group: R3{sup ¯}m) of As{sub 2}Te{sub 3} (β-As{sub 2}Te{sub 3}) through first-principles calculations including spin-orbit coupling within density functional theory. The ETT in β-As{sub 2}Te{sub 3} is shown to occur at the uniaxial strain ϵ{sub zz} = −0.05 (σ{sub zz} = 1.77 GPa), passing through a Weyl metallic state with a single Dirac cone in its electronic structure at the Γ point. We demonstrate the ETT through band inversion and reversal of parity of the top of the valence and bottom of the conduction bands leading to change in the ℤ{sub 2} topological invariant ν{sub 0} from 0 to 1 across the transition. Based on its electronic structure and phonon dispersion, we propose ultra-thin films of As{sub 2}Te{sub 3} to be promising for use in ultra-thin stress sensors, charge pumps, and thermoelectrics.

  2. Comparison of quantification methods illustrates reduced Pseudomonas aeruginosa activity on nanorough polyvinyl chloride.

    PubMed

    Seil, Justin T; Rubien, Nathan M; Webster, Thomas J; Tarquinio, Keiko M

    2011-07-01

    Patients on mechanical ventilators for extended periods of time are faced with a high probability of developing ventilator associated pneumonia. Although this has been mostly addressed through the re-engineering of endotracheal tubes (ETTs) with antimicrobial materials, such material coatings may easily delaminate during use. However, the potential exists to apply nanotechnology to the ETT to avoid delamination but implement antibacterial properties. Selecting a protocol to evaluate in vitro material for anti-infection is difficult, partially due to the existence of conflicting reported methods of analysis. In this study, the susceptibility of conventional and nanorough polymeric materials to bacterial biofilm growth were evaluated. After creating nanorough polyvinyl chloride (PVC) ETTs, Pseudomonas aeruginosa biofilms were then grown on sample surfaces during a 24-h culture. Biofilms were then removed and assayed from sample surfaces using a variety of techniques. Comparisons between the different techniques used for biofilm removal indicated that vortexing provided adequate removal of the biofilm from sample surfaces. Most importantly, a protocol following the vortexing method of biofilm and bacteria removal provided an ∼40% lower yield of colony forming units from nanorough PVC compared to conventional PVC. This suggests that Pseudomonas aeruginosa are less adherent on nanorough PVC than conventional PVC.

  3. Incidental diagnosis of an H-type tracheo-oesophageal fistula.

    PubMed

    Donnelly, Peter; McVea, Steven; Flannigan, Christopher; Bali, Sanjeev

    2016-06-29

    A 6-day-old term neonate who was intubated on day 1 of life for apnoeic episodes, was transferred to the regional paediatric intensive care unit (PICU) for specialist opinion following 3 failed extubations in the neonatal unit. Escherichia coli congenital pneumonia was diagnosed and the child discharged to the local hospital. Chest radiographs and inflammatory markers were in keeping with infection. However, ongoing difficulties with secretions necessitated readmission to the PICU, following a significant cyanotic episode associated with coughing. On arrival at the PICU, a large leak around the endotracheal tube (ETT) was noted. On direct laryngoscopy, the ETT was found correctly positioned, through the cords, but air was noted to be coming back from the oesophagus. Advancing the ETT towards the carina terminated the leak and raised the suspicion of a tracheo-oesophageal fistula. An H-type tracheo-oesophageal fistula was confirmed on bronchoscopy. An uneventful fistula repair was performed and the baby discharged from the PICU on day 23 of life.

  4. Fluid flow and particle transport in mechanically ventilated airways. Part II: particle transport.

    PubMed

    Alzahrany, Mohammed; Van Rhein, Timothy; Banerjee, Arindam; Salzman, Gary

    2016-07-01

    The flow mechanisms that play a role on aerosol deposition were identified and presented in a companion paper (Timothy et al. in Med Biol Eng Comput. doi: 10.1007/s11517-015-1407-3 , 2015). In the current paper, the effects of invasive conventional mechanical ventilation waveforms and endotracheal tube (ETT) on the aerosol transport were investigated. In addition to the enhanced deposition seen at the carinas of the airway bifurcations, enhanced deposition was also seen in the right main bronchus due to impaction and turbulent dispersion resulting from the fluid structures created by jet caused by the ETT. The orientation of the ETT toward right bronchus resulted in a substantial deposition inside right lung compared to left lung. The deposition inside right lung was ~12-fold higher than left lung for all considered cases, except for the case of using pressure-controlled sinusoidal waveform where a reduction of this ratio by ~50 % was found. The total deposition during pressure constant, volume ramp, and ascending ramp waveforms was similar and ~1.44 times higher than deposition fraction when using pressure sinusoidal waveform. Varying respiratory waveform demonstrated a significant role on the deposition enhancement factors and give evidence of drug aerosol concentrations in key deposition sites, which may be significant for drugs with negative side effects in high concentrations. These observations are thought to be important for ventilation treatment strategy. PMID:26541600

  5. Epithelioid trophoblastic tumor of the uterus in a postmenopausal woman: a case report and review of the literature.

    PubMed

    Coulson, L E; Kong, C S; Zaloudek, C

    2000-11-01

    We report an epithelioid trophoblastic tumor (ETT), a recently delineated type of gestational trophoblastic tumor (GTT), discovered in the uterus of a 66-year-old woman. She had been treated for a hydatidiform mole 17 years previously without chemotherapy. The resected uterus contained a solid/cystic tumor located entirely within the myometrium. Microscopically, there was an epithelial-like growth pattern. The tumor was circumscribed, with a pushing border, and the tumor cells grew in cords, nests, and sheets within which were aggregates of hyaline material and necrotic debris. Most tumor cells were mononuclear and had an epithelioid appearance with distinct cell borders, eosinophilic cytoplasm, and nuclei with occasional indistinct nucleoli. Scattered multinucleated cells consistent with syncytiotrophoblastic cells were also present. Immunohistochemical staining revealed strong diffuse reactivity for cytokeratins (CK7, AE1/AE3, CAM 5.2, CK18) and epidermal growth factor receptor, and focal reactivity, mainly in syncytiotrophoblastic cells, for beta-human chorionic gonadotropin, human placental lactogen, and inhibin-alpha. The histologic and immunohistochemical features were characteristic of ETT, and helped to distinguish the tumor from other trophoblastic tumors and squamous cell carcinoma. An unusual observation was a high mitotic count, reflected in a Ki-67 proliferative index of 68.6%. Our findings indicate that ETT, like other types of GTT, can occur in postmenopausal women, even years after a gestational event.

  6. Intracuff alkalized lidocaine reduces sedative/analgesic requirements for mechanically ventilated patients

    PubMed Central

    Basuni, Ahmed Sobhy

    2014-01-01

    Background: The objective of this study is to investigate the effect of intracuff alkalized lidocaine on sedative/analgesic requirements for mechanically ventilated patients and its consequence on patient-ventilator interaction. Materials and Methods: A total of 64 patients who expected to require ventilatory support for a period of more than 48 h were randomly assigned to groups S and L. In group S, the endotracheal tube (ETT) cuffs were inflated with normal saline. In group L, the ETT cuffs were inflated with lidocaine 2% and sodium bicarbonate 8.4%. The investigator and the surgical intensive care unit staff were blinded to the nature of cuff-filled solutions. Sedation was maintained with propofol and fentanyl infusions. The total requirements for propofol and fentanyl, frequency and severity of cough and number of ineffective triggering during the first 24 h of mechanical ventilation were recorded. Results: There was a significant reduction (about 30%) in the requirements for propofol and fentanyl in patients who received intracuff alkalinized lidocaine; P < 0.001. The frequency and severity of cough were significantly lower in group L compared with group S and the frequency of ineffective triggering was significantly lower in group L; P < 0.001 for both comparisons. Conclusion: Intracuff alkalized lidocaine increases ETT tolerance and hence, decreases sedatives/analgesics requirements for mechanically ventilated patients. This results in improved patient-ventilator synchronization. PMID:25422600

  7. FTIR gas-phase kinetic study on the reactions of OH radicals and Cl atoms with unsaturated esters: Methyl-3,3-dimethyl acrylate, (E)-ethyl tiglate and methyl-3-butenoate

    NASA Astrophysics Data System (ADS)

    Colomer, Juan P.; Blanco, María B.; Peñéñory, Alicia B.; Barnes, Ian; Wiesen, Peter; Teruel, Mariano A.

    2013-11-01

    The relative-rate technique has been used to obtain rates coefficients for the reactions of the unsaturated esters methyl-3,3-dimethyl acrylate, (E)-ethyl tiglate and methyl-3-butenoate with OH radicals and chlorine atoms at (298 ± 2) K in synthetic air at a total pressure of (760 ± 10) Torr. The experiments were performed in an environmental chamber using in situ FTIR detection to monitor the decay of the esters relative to different reference compounds. The following room temperature rate coefficients (in units of cm3 molecule-1 s-1) were obtained: k1(OH + (CH3)2Cdbnd CHC(O)OCH3) = (4.46 ± 1.05) × 10-11, k2(Cl + (CH3)2Cdbnd CHC(O)OCH3) = (2.78 ± 0.46) × 10-10, k3(OH + CH3CHdbnd C(CH3)C(O)OCH2CH3) = (8.32 ± 1.93) × 10-11, k4(Cl + CH3CHdbnd C(CH3)C(O)OCH2CH3) = (2.53 ± 0.35) × 10-10, k5(OH + CH2dbnd CHCH2C(O)OCH3) = (3.16 ± 0.57) × 10-11, k4(Cl + CH2dbnd CHCH2C(O)OCH3) = (2.10 ± 0.35) × 10-10. With the exception of the reaction of Cl with methyl-3,3-dimethyl acrylate (k2), for which one determination exists in the literature, this study is the first kinetic study for these reactions under atmospheric pressure. Reactivity trends are discussed in terms of the effect of the alkyl and ester groups attached to the double bond on the overall rate coefficients towards OH radicals. The atmospheric implications of the reactions were assessed by the estimation of the tropospheric lifetimes of the title reactions.

  8. Achieving a Safe Endotracheal Tube Cuff Pressure in the Prehospital Setting: Is It Time to Revise the Standard Cuff Inflation Practice?

    PubMed

    Carhart, Elliot; Stuck, Logan H; Salzman, Joshua G

    2016-01-01

    Numerous studies have reported unsafe endotracheal tube (ETT) cuff pressures (CP) in the prehospital environment. The purpose of this study was to identify an optimal cuff inflation volume (CIV) to achieve a safe CP (20-30 cmH2O). This observational study utilized 30 recently harvested ovine tracheae, which were warmed from refrigeration in a water bath at 85°F prior to testing. Each trachea was intubated with five different ETT sizes (6.0-8.0 mm), and each size tube was tested with six cuff inflation volumes (5-10 cc). The order of ETT size for each trachea and CIV for each size ETT was randomly pre-assigned. Data were descriptively summarized and categorized before mixed-effects logistic regression was used to determine optimal CIV. Only 113 CP measurements (12.6%, N = 900) were within the optimal range (M = 54.75 cmH2O, SD = 38.52), all of which resulted from a CIV 6 or 7 cc (61% and 39%, respectively). CIVs of 5 cc (n = 150) resulted in underinflation (<20 cmH2O) in all instances, while CIVs of 8, 9, or 10 cc (n = 150 each) resulted in overinflation (>30 cmH2O) in all instances, regardless of ETT size. The odds of achieving a safe CP were greater with CIV of 6 cc for tube sizes 6.0 (OR = 15.9, 95% CI = 3.85-65.58, p < 0.01) and 6.5 mm (OR = 3.16, 95% CI = 1.06-9.39, p = 0.039); however, there was no significant difference in the odds of achieving a safe CP between CIV of 6 and 7 cc for tube sizes 7.0, 7.5, or 8.0 mm. Neither trachea circumference (M = 7.11 cm, SD = 0.40), nor tissue temperature (M = 81.32°F, SD = 0.93) were found to be significant predictors of CP (p = 0.20 and 0.81, respectively). Our study showed a high frequency of CP measurements outside of the desired norms. The CIV range of 6-7 cc resulted in the highest likelihood of achieving the desired cuff pressure range, while cuffs inflated with 8-10 cc resulted in dangerously high CPs in all instances. In the absence of a more ideal solution, the results of this study suggest that narrowing the

  9. Method for synthesizing thin film electrodes

    DOEpatents

    Boyle, Timothy J.

    2007-03-13

    A method for making a thin-film electrode, either an anode or a cathode, by preparing a precursor solution using an alkoxide reactant, depositing multiple thin film layers with each layer approximately 500 1000 .ANG. in thickness, and heating the layers to above 600.degree. C. to achieve a material with electrochemical properties suitable for use in a thin film battery. The preparation of the anode precursor solution uses Sn(OCH.sub.2C(CH.sub.3).sub.3).sub.2 dissolved in a solvent in the presence of HO.sub.2CCH.sub.3 and the cathode precursor solution is formed by dissolving a mixture of (Li(OCH.sub.2C(CH.sub.3).sub.3)).sub.8 and Co(O.sub.2CCH.sub.3).H.sub.2O in at least one polar solvent.

  10. Differentiation of neotropical fish species with statistical analysis of fourier transform infrared photoacoustic spectroscopy data.

    PubMed

    Almeida, Francylaine S; Lima, Sandro M; Andrade, Luis H C; Súarez, Yzel R

    2012-07-01

    Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was applied to nineteen fish species in Brazil's Upper Paraná River basin to identify differences in the structural composition of their scales. To differentiate the species, a canonical discriminant analysis was used to indicate the most important absorption peaks in the mid-infrared region. Significant differences were found in the chemical composition of scales among the studied fish species, with Wilk's lambda = 5.2 × 10(-6), F((13,18,394)) = 37.57, and P < 0.001, indicating that O-CH(2) wag at 1396 cm(-1) can be used as a biomarker of this species group. The species could be categorized into four groups according to phylogenetic similarity, suggesting that the O-CH(2) 1396 cm(-1) absorbance is related to the biological traits of each species. This procedure can also be used to complement evolutionary studies.

  11. High resolution electronic spectra of anisole and anisole-water in the gas phase: hydrogen bond switching in the S1 state.

    PubMed

    Ribblett, J W; Sinclair, W E; Borst, D R; Yi, J T; Pratt, D W

    2006-02-01

    Rotationally resolved S(1)<--S(0) electronic spectra of anisole and its hydrogen bonded complex containing one water molecule have been obtained. The results provide evidence for an "in-plane" complex in which the water molecule is attached via two hydrogen bonds to the anisole molecule, a donor O-H- - -O(CH(3)) bond and an acceptor H-O- - -H(ring) bond. Analysis of the subbands that appear in the spectrum of the complex suggests that hydrogen bond "switching" occurs when the complex absorbs light. The former O-H- - -O(CH(3)) bond is stronger in the ground (S(0)) state, whereas the latter H-O- - -H(ring) bond is stronger in the excited (S(1)) state. Dynamical consequences of this phenomenon are discussed.

  12. The Synthesis and Characterization of Aromatic Hybrid Anderson-Evans POMs and their Serum Albumin Interactions: The Shift from Polar to Hydrophobic Interactions.

    PubMed

    Al-Sayed, Emir; Blazevic, Amir; Roller, Alexander; Rompel, Annette

    2015-12-01

    Four aromatic hybrid Anderson polyoxomolybdates with Fe(3+) or Mn(3+) as the central heteroatom have been synthesized by using a pre-functionalization protocol and characterized by using single-crystal X-ray diffraction, FTIR, ESI-MS, (1) H NMR spectroscopy, and elemental analysis. Structural analysis revealed the formation of (TBA)3 [FeMo6 O18 {(OCH2 )3 CNHCOC6 H5 }2 ]⋅3.5 ACN (TBA-FeMo6 -bzn; TBA=tetrabutylammonium, ACN=acetonitrile, bzn=TRIS-benzoic acid alkanolamide, TRISR=(HOCH2 )3 CR)), (TBA)3 [FeMo6 O18 {(OCH2 )3 CNHCOC8 H7 }2 ]⋅2.5 ACN (TBA-FeMo6 -cin; cin=TRIS-cinnamic acid alkanolamide), (TBA)3 [MnMo6 O18 {(OCH2 )3 CNHCOC6 H5 }2 ]⋅3.5 ACN (TBA-MnMo6 -bzn), and (TBA)3 [MnMo6 O18 {(OCH2 )3 CNHCOC8 H7 }2 ]⋅2.5 ACN (TBA-MnMo6 -cin). To make these four compounds applicable in biological systems, an ion exchange was performed that gave the water-soluble (up to 80 mM) sodium salts Na3 [FeMo6 O18 {(OCH2 )3 CNHCOC6 H5 }2 ] (Na-FeMo6 -bzn), Na3 [FeMo6 O18 {(OCH2 )3 CNHCOC8 H7 }2 ] (Na-FeMo6 -cin), Na3 [MnMo6 O18 {(OCH2 )3 CNHCOC6 H5 }2 ] (Na-MnMo6 -bzn), and Na3 [MnMo6 O18 {(OCH2 )3 CNHCOC8 H7 }2 ] (Na-MnMo6 -cin). The hydrolytic stability of the sodium salts was examined by applying ESI-MS in the pH range of 4 to 9. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that human and bovine serum albumin (HSA and BSA) remain intact in solutions that contain up to 100 equivalents of the sodium salts over more than 4 d at 20 °C. Tryptophan (Trp) fluorescence quenching was applied to study the interactions between the sodium salts and HSA and BSA at pH 5.5 and 7.4. The quenching constants were extracted by using Stern-Volmer analysis, which suggested the formation of a 1:1 POM-protein complex in all samples. It is suggested that the aromatic hybrid POM approaches subdomain IIA of HSA and exhibits hydrophobic interactions with its hydrophobic tails, whereas the Anderson core is stabilized through electrostatic

  13. Increasing the activity and enantioselectivity of lipases by sol-gel immobilization: further advancements of practical interest.

    PubMed

    Tielmann, Patrick; Kierkels, Hans; Zonta, Albin; Ilie, Adriana; Reetz, Manfred T

    2014-06-21

    The entrapment of lipases in hydrophobic silicate matrices formed by sol-gel mediated hydrolysis of RSi(OCH3)3/Si(OCH3)4 as originally reported in 1996 has been improved over the years by a number of modifications. In the production of second-generation sol-gel lipase immobilizates, a variety of additives during the sol-gel process leads to increased activity and enhanced stereoselectivity in esterifying kinetic resolution. Recent advances in this type of lipase immobilization are reviewed here, in addition to new results regarding the sol-gel entrapment of the lipase from Burkholderia cepacia. It constitutes an excellent heterogeneous biocatalyst in the acylating kinetic resolution of two synthetically and industrially important chiral alcohols, rac-sulcatol and rac-trans-2-methoxycyclohexanol. The observation that the catalyst can be used 10 times in recycling experiments without losing its significant activity or enantioselectivity demonstrates the practical viability of the sol-gel approach.

  14. Langmuir monolayers and thin films of amphifilic thiacalix[4]arenes. Properties and matrix for the immobilization of cytochrome c.

    PubMed

    Solovieva, Svetlana E; Safiullin, Roman A; Kochetkov, Evgeni N; Melnikova, Nina B; Kadirov, Marsil K; Popova, Elena V; Antipin, Igor S; Konovalov, Alexander I

    2014-12-23

    Formation and properties of Langmuir films of thiacalix[4]arene (TCA) derivatives containing N-donor groups on the lower rim (Y═O(CH2)3CN; OCH2CN; NH2; OCH2ArCN-p) in 1,3-alternate conformation on aqueous subphase and solid substrates have been studied. Only tetra-cyanopropoxy-p-tert-butylthiacalix[4]arene 1 forms a typical monomolecular layer with perpendicular orientation of the macrocycle relative to the water-air interface that is able to immobilize cytochrome c in the entire range of the surface pressure. Obtained monolayers were transferred by Langmuir-Schaefer technique onto quartz, indium-tin oxide (ITO), and silicon. It was demonstrated that protein activity is retained after immobilization on the substrate. PMID:25435075

  15. Global seamless network demonstrator: carrier grade automatic switched transport network implementation in realistic telecom field environment

    NASA Astrophysics Data System (ADS)

    Foisel, Hans-Martin; Hanik, Norbert; Braun, Ralf-Peter; Lehr, Georg; Gladisch, Andreas

    2004-04-01

    The Global Seamless Network (GSN) Demonstrator is presented, a joint effort of system vendors and Deutsche Telekom Group R&D to demonstrate network functions and management integration and enable, for the first time, experiences with a carrier grade Automatically Switched Transport Network (ASTN) implementation and the envisaged main ASTN clients, IP and Ethernet. For end-to-end monitoring capability, integrating the view on the ASTN and Ethernet-MAN configuration, an UMS (Upper Monitoring System) is being developed. Furthermore broadband application were implemented to visualise the network functions. The ASTN backbone consists of four cross connects and an ULH-WDM system with 3x 10Gbit/s channels (OCh) between Berlin and Darmstadt, whereby each OCh is treated as a virtual fibre.

  16. Estimation of the catalytic centre in double metal cyanide catalysts by XAS

    NASA Astrophysics Data System (ADS)

    Lawniczak-Jablonska, Krystyna; Chrusciel, Arkadiusz

    2016-05-01

    Double metal cyanide (DMC) catalysts are commonly applied at industrial ring opening polymerization of epoxides. Nevertheless, the knowledge on the molecular nature of their high activity and selectivity is limited. XAS studies were performed to look for the possible catalytic centre in this family of catalysts. DMC catalysts were synthesized from ZnCl2 and potassium hexacyanocobaltate(III) solution, in the presence of the different organic ligands and show significant fraction of the non-crystalline structure. Two ligands were analysed (tert-butanol ( t BuOH) or glyme (CH3OCH2CH2OCH3)). EXAFS analysis established that only Zn atoms are the active metallic centers in DMC regardless the used ligand. The coordination around Zn was changed from octahedral in reference non catalytic material to tetrahedral in catalysts, and Cl atoms were detected near some of Zn atoms.

  17. The Synthesis and Characterization of Aromatic Hybrid Anderson–Evans POMs and their Serum Albumin Interactions: The Shift from Polar to Hydrophobic Interactions

    PubMed Central

    Al-Sayed, Emir; Blazevic, Amir; Roller, Alexander; Rompel, Annette

    2015-01-01

    Four aromatic hybrid Anderson polyoxomolybdates with Fe3+ or Mn3+ as the central heteroatom have been synthesized by using a pre-functionalization protocol and characterized by using single-crystal X-ray diffraction, FTIR, ESI-MS, 1H NMR spectroscopy, and elemental analysis. Structural analysis revealed the formation of (TBA)3[FeMo6O18{(OCH2)3CNHCOC6H5}2]⋅3.5 ACN (TBA-FeMo6-bzn; TBA=tetrabutylammonium, ACN=acetonitrile, bzn=TRIS-benzoic acid alkanolamide, TRIS–R=(HOCH2)3C–R)), (TBA)3[FeMo6O18{(OCH2)3CNHCOC8H7}2]⋅2.5 ACN (TBA-FeMo6-cin; cin=TRIS-cinnamic acid alkanolamide), (TBA)3[MnMo6O18{(OCH2)3CNHCOC6H5}2]⋅3.5 ACN (TBA-MnMo6-bzn), and (TBA)3[MnMo6O18{(OCH2)3CNHCOC8H7}2]⋅2.5 ACN (TBA-MnMo6-cin). To make these four compounds applicable in biological systems, an ion exchange was performed that gave the water-soluble (up to 80 mm) sodium salts Na3[FeMo6O18{(OCH2)3CNHCOC6H5}2] (Na-FeMo6-bzn), Na3[FeMo6O18{(OCH2)3CNHCOC8H7}2] (Na-FeMo6-cin), Na3[MnMo6O18{(OCH2)3CNHCOC6H5}2] (Na-MnMo6-bzn), and Na3[MnMo6O18{(OCH2)3CNHCOC8H7}2] (Na-MnMo6-cin). The hydrolytic stability of the sodium salts was examined by applying ESI-MS in the pH range of 4 to 9. Sodium dodecylsulfate–polyacrylamide gel electrophoresis (SDS-PAGE) showed that human and bovine serum albumin (HSA and BSA) remain intact in solutions that contain up to 100 equivalents of the sodium salts over more than 4 d at 20 °C. Tryptophan (Trp) fluorescence quenching was applied to study the interactions between the sodium salts and HSA and BSA at pH 5.5 and 7.4. The quenching constants were extracted by using Stern–Volmer analysis, which suggested the formation of a 1:1 POM–protein complex in all samples. It is suggested that the aromatic hybrid POM approaches subdomain IIA of HSA and exhibits hydrophobic interactions with its hydrophobic tails, whereas the Anderson core is stabilized through electrostatic interactions with polar amino acid side chains from, for example

  18. A Polyurethane Surface Modifier: Contrasting Amphiphilic and Contraphilic Surfaces Driven by block and random Soft Blocks having Trifluoroethoxymethyl and PEG Side Chains

    PubMed Central

    Zhang, Wei; Fujiwara, Tomoko; Taşkent, Hűmeyra; Zheng, Ying; Brunson, Kennard; Gamble, Lara; Wynne, Kenneth J.

    2013-01-01

    A conventional MDI-BD-PTMO polyurethane was modified using 2 wt.% polyurethanes (U) having copolyoxetane soft blocks with hydrophobic 3F, CF3CH2OCH2- and hydrophilic MEn, CH3O(CH2CH2O)nCH2-, n = 3, 7) side chains. In contrast to neat 3F-co-MEn-U, 2 wt.% 3F-co-MEn-U compositions have physically stable morphologies and wetting behavior. Surface composition (XPS) and amphiphilic or contraphilic wetting are controlled by the 3F-co-MEn polyoxetane soft block architecture and MEn side chain length. Importantly, θrec can be tuned for 2 wt.% 3F-co-MEn-U compositions independent of swelling, which is controlled by the bulk polyurethane. AFM imaging led to a new morphological model whereby fluorous/PEG-hard block nano-aggregates combine to form near surface features culminating in micron scale texturing. PMID:24204100

  19. Langmuir monolayers and thin films of amphifilic thiacalix[4]arenes. Properties and matrix for the immobilization of cytochrome c.

    PubMed

    Solovieva, Svetlana E; Safiullin, Roman A; Kochetkov, Evgeni N; Melnikova, Nina B; Kadirov, Marsil K; Popova, Elena V; Antipin, Igor S; Konovalov, Alexander I

    2014-12-23

    Formation and properties of Langmuir films of thiacalix[4]arene (TCA) derivatives containing N-donor groups on the lower rim (Y═O(CH2)3CN; OCH2CN; NH2; OCH2ArCN-p) in 1,3-alternate conformation on aqueous subphase and solid substrates have been studied. Only tetra-cyanopropoxy-p-tert-butylthiacalix[4]arene 1 forms a typical monomolecular layer with perpendicular orientation of the macrocycle relative to the water-air interface that is able to immobilize cytochrome c in the entire range of the surface pressure. Obtained monolayers were transferred by Langmuir-Schaefer technique onto quartz, indium-tin oxide (ITO), and silicon. It was demonstrated that protein activity is retained after immobilization on the substrate.

  20. Anderson-like alkoxo-polyoxovanadate clusters serving as unprecedented second building units to construct metal-organic polyhedra.

    PubMed

    Zhang, Yu-Teng; Wang, Xin-Long; Li, Shuang-Bao; Gong, Ya-Ru; Song, Bai-Qiao; Shao, Kui-Zhan; Su, Zhong-Min

    2016-08-11

    Unprecedented Anderson-like alkoxo-polyoxovanadate [V6O6(OCH3)9(μ6-SO4)(COO)3](2-) polyanions can serve as 3-connected second building units (SBUs) that assemble with dicarboxylate or tricarboxylate ligands to form a new family of metal organic tetrahedrons of V4E6 and V4F4 type (V = vertex, E = edge, and F = face). To our knowledge, this alkoxo-polyoxovanadate-based SBU is the first ever reported. PMID:27363544

  1. Unimolecular thermal decomposition of dimethoxybenzenes

    SciTech Connect

    Robichaud, David J. Mukarakate, Calvin; Nimlos, Mark R.; Scheer, Adam M.; Ormond, Thomas K.; Buckingham, Grant T.; Ellison, G. Barney

    2014-06-21

    The unimolecular thermal decomposition mechanisms of o-, m-, and p-dimethoxybenzene (CH{sub 3}O-C{sub 6}H{sub 4}-OCH{sub 3}) have been studied using a high temperature, microtubular (μtubular) SiC reactor with a residence time of 100 μs. Product detection was carried out using single photon ionization (SPI, 10.487 eV) and resonance enhanced multiphoton ionization (REMPI) time-of-flight mass spectrometry and matrix infrared absorption spectroscopy from 400 K to 1600 K. The initial pyrolytic step for each isomer is methoxy bond homolysis to eliminate methyl radical. Subsequent thermolysis is unique for each isomer. In the case of o-CH{sub 3}O-C{sub 6}H{sub 4}-OCH{sub 3}, intramolecular H-transfer dominates leading to the formation of o-hydroxybenzaldehyde (o-HO-C{sub 6}H{sub 4}-CHO) and phenol (C{sub 6}H{sub 5}OH). Para-CH{sub 3}O-C{sub 6}H{sub 4}-OCH{sub 3} immediately breaks the second methoxy bond to form p-benzoquinone, which decomposes further to cyclopentadienone (C{sub 5}H{sub 4}=O). Finally, the m-CH{sub 3}O-C{sub 6}H{sub 4}-OCH{sub 3} isomer will predominantly follow a ring-reduction/CO-elimination mechanism to form C{sub 5}H{sub 4}=O. Electronic structure calculations and transition state theory are used to confirm mechanisms and comment on kinetics. Implications for lignin pyrolysis are discussed.

  2. A selenium-based ionic liquid as a recyclable solvent for the catalyst-free synthesis of 3-selenylindoles.

    PubMed

    Zimmermann, Everton G; Thurow, Samuel; Freitas, Camilo S; Mendes, Samuel R; Perin, Gelson; Alves, Diego; Jacob, Raquel G; Lenardão, Eder J

    2013-04-05

    The ionic liquid 1-butyl-3-methylimidazolium methylselenite, [bmim][SeO2(OCH3)], was successfully used as solvent in the catalyst-free preparation of 3-arylselenylindoles by the reaction of indole with ArSeCl at room temperature. The products were obtained selectively in good yields without the need of any additive and the solvent was easily reused for several cycles with good results.

  3. Towards a synthetic glycoconjugate vaccine against Neisseria meningitidis A.

    PubMed

    Berkin, Ali; Coxon, Bruce; Pozsgay, Vince

    2002-10-01

    Albumin conjugates of synthetic fragments of the capsular polysaccharide of the Gram-negative bacterium Neisseria meningitidis serogroup A were prepared. The fragments include monosaccharides 1 [alpha-D-ManpNAc-(1-->O)-(CH(2))(2)NH(2)] and 2 [6-O-P(O)(O(-))(2)-alpha-D-ManpNAc-(1-->O)-(CH(2))(2)NH(2)], disaccharide 3 [alpha-D-ManpNAc-[1-->O-P(O)(O(-))-->6]-alpha-D-ManpNAc-(1-->O)-(CH(2))(2)NH(2)], and trisaccharide 4 [alpha-D-ManpNAc-[1-->O-P(O)(O(-))-->6]-alpha-D-ManpNAc-[1-->O-P(O)(O(-))-->6]-alpha-D-ManpNAc-(1-->O)-(CH(2))(2)NH(2)]. Two monosaccharide blocks were employed as key intermediates. The reducing-end mannose unit featured the NHAc group at C-2, and contained the aminoethyl spacer as the aglycon for the final bioconjugation. The interresidual phosphodiester linkages were fashioned from an anomerically positioned H-phosphonate group in a 2-azido-mannose building block. The spacer-linked saccharides 1-4 were N-acylated with hepta-4,6-dienoic acid and the resulting conjugated diene-equipped saccharides were subjected to Diels-Alder-type addition with maleimidobutyryl-group functionalized human serum albumin to form covalent conjugates containing up to 26 saccharide haptens per albumin molecule. Complete (1)H, (13)C, and (31)P NMR assignments for 1-4 are given. Antigenicity of the neoglycoconjugates containing 1-4 was demonstrated by a double immunodiffusion assay which indicated that a fragment as small as a monosaccharide is recognized by a polyclonal meningococcus group A antiserum and that the O-acetyl group(s) present in the natural capsular material is not essential for antigenicity. PMID:12355530

  4. Structures of the gauche conformers of somE substituted dimethyl ethers. Effect of adjacent atom lone pairs on methyl group asymmetry

    NASA Astrophysics Data System (ADS)

    Boggs, James E.; Altman, Michael; Cordell, Floyd R.; Dai, Yuanfang

    The complete equilibrium structures of CH 3OCH 3 and of the gauche conformers of CH 30CH 2F, HOCH,F, CH,OCH,Cl and CH,OCH,CN have been determined by ab initio gradient computation at the Hartree-Fock, double zeta-plus-polarization level. The very large asymmetries in CH bond distances previously reported from microwave substitution structures are shown to be non-existent in the equilibrium structures and are presumably artifacts. Small differences, different in direction from those reported from the experiments and nearly an order of magnitude smaller in size, do exist. They reflect three factors: (1) a lengthening of a CH bond which is trans to a lone pair on an adjacent atom, (2) a general shortening of CH bonds originating at a carbon atom bearing a highly electronegative substituent, and (3) a specific interaction in which a CX substituent shortens the nearly parallel CH bond on the other methyl group. The last interaction, not previously reported, is mediated by withdrawal of electron density from the oxygen lone pair which is trans to both groups. Other structural features derived from the microwave studies are supported by the new results. Inclusion of polarization functions in the basis set for oxygen is essential for correct determination of the COC angle and the dihedral angles. The dihedral angles of CH 3OCH 2F and HOCH 2F are not correctly determined by the computation even at this level, although the computed values are improved when d functions are used for oxygen and still more by use of two sets of oxygen d functions. Polarization functions on carbon or on fluorine have no effect on the computed torsional angles. There is no problem in computing the correct dihedral angles with the CI or CN derivatives.

  5. Multilingual Affordances in a Swedish Preschool: An Action Research Project

    ERIC Educational Resources Information Center

    Ljunggren, Åsa

    2016-01-01

    This article summarizes the work and the main findings of an action research project that was conducted in an early childhood education and care setting in the city of Malmö, Sweden in the autumn of 2013 and spring 2014. Rönnerman's model (Aktionsforskning i praktiken: förskola och skola på vetenskaplig grund [Action research in practice:…

  6. Theoretical spectroscopic characterization at low temperatures of S-methyl thioformate and O-methyl thioformate.

    PubMed

    Senent, M L; Puzzarini, C; Hochlaf, M; Domínguez-Gómez, R; Carvajal, M

    2014-09-14

    Highly correlated ab initio methods are employed to determine spectroscopic properties at low temperatures of two S-analogs of methyl formate: S-methyl thioformate CH3-S-CHO (MSCHO) and O-methyl thioformate CH3-O-CHS (MOCHS). Both species are detectable and they are expected to play an important role in Astrochemistry. Molecular properties are compared with those of the O-analog, methyl formate. Both isomers present two conformers cis and trans. cis-CH3-S-CHO represents the most stable structure lying 4372.2 cm(-1) below cis-CH3-O-CHS. The energy difference between the cis and trans forms is drastically lower for MSCHO (1134 cm(-1)) than for MOCHS (1963.6 cm(-1)). Harmonic and anharmonic fundamentals and the corresponding intensities, as well as the rotational constants for the ground vibrational and first excited torsional states and the centrifugal distortions constants, are provided. Low torsional energy levels have been obtained by solving variationally a two dimensional Hamiltonian expressed in terms of the two torsional degrees of freedom. The corresponding 2D potential energy surfaces have been computed at the CCSD(T)/aug-cc-pVTZ level of theory. The methyl torsional barriers V3(cis) are determined to be 139.7 cm(-1) (CH3-S-CHO) and 670.4 cm(-1) (CH3-O-CHS). The A/E splitting of ground torsional state has been estimated to be 0.438 cm(-1) for CH3-S-CHO and negligible for CH3-O-CHS.

  7. Theoretical spectroscopic characterization at low temperatures of S-methyl thioformate and O-methyl thioformate.

    PubMed

    Senent, M L; Puzzarini, C; Hochlaf, M; Domínguez-Gómez, R; Carvajal, M

    2014-09-14

    Highly correlated ab initio methods are employed to determine spectroscopic properties at low temperatures of two S-analogs of methyl formate: S-methyl thioformate CH3-S-CHO (MSCHO) and O-methyl thioformate CH3-O-CHS (MOCHS). Both species are detectable and they are expected to play an important role in Astrochemistry. Molecular properties are compared with those of the O-analog, methyl formate. Both isomers present two conformers cis and trans. cis-CH3-S-CHO represents the most stable structure lying 4372.2 cm(-1) below cis-CH3-O-CHS. The energy difference between the cis and trans forms is drastically lower for MSCHO (1134 cm(-1)) than for MOCHS (1963.6 cm(-1)). Harmonic and anharmonic fundamentals and the corresponding intensities, as well as the rotational constants for the ground vibrational and first excited torsional states and the centrifugal distortions constants, are provided. Low torsional energy levels have been obtained by solving variationally a two dimensional Hamiltonian expressed in terms of the two torsional degrees of freedom. The corresponding 2D potential energy surfaces have been computed at the CCSD(T)/aug-cc-pVTZ level of theory. The methyl torsional barriers V3(cis) are determined to be 139.7 cm(-1) (CH3-S-CHO) and 670.4 cm(-1) (CH3-O-CHS). The A/E splitting of ground torsional state has been estimated to be 0.438 cm(-1) for CH3-S-CHO and negligible for CH3-O-CHS. PMID:25217912

  8. Theoretical spectroscopic characterization at low temperatures of S-methyl thioformate and O-methyl thioformate

    SciTech Connect

    Senent, M. L.; Puzzarini, C.; Hochlaf, M.; Domínguez-Gómez, R.; Carvajal, M.

    2014-09-14

    Highly correlated ab initio methods are employed to determine spectroscopic properties at low temperatures of two S-analogs of methyl formate: S-methyl thioformate CH{sub 3}-S-CHO (MSCHO) and O-methyl thioformate CH{sub 3}-O-CHS (MOCHS). Both species are detectable and they are expected to play an important role in Astrochemistry. Molecular properties are compared with those of the O-analog, methyl formate. Both isomers present two conformers cis and trans. cis-CH{sub 3}-S-CHO represents the most stable structure lying 4372.2 cm{sup −1} below cis-CH{sub 3}-O-CHS. The energy difference between the cis and trans forms is drastically lower for MSCHO (1134 cm{sup −1}) than for MOCHS (1963.6 cm{sup −1}). Harmonic and anharmonic fundamentals and the corresponding intensities, as well as the rotational constants for the ground vibrational and first excited torsional states and the centrifugal distortions constants, are provided. Low torsional energy levels have been obtained by solving variationally a two dimensional Hamiltonian expressed in terms of the two torsional degrees of freedom. The corresponding 2D potential energy surfaces have been computed at the CCSD(T)/aug-cc-pVTZ level of theory. The methyl torsional barriers V{sub 3}(cis) are determined to be 139.7 cm{sup −1} (CH{sub 3}-S-CHO) and 670.4 cm{sup −1} (CH{sub 3}-O-CHS). The A/E splitting of ground torsional state has been estimated to be 0.438 cm{sup −1} for CH{sub 3}-S-CHO and negligible for CH{sub 3}-O-CHS.

  9. Influence of molybdenum on the accumulation and composition of the water-soluble polysaccharides of Plantago psyllium

    SciTech Connect

    Lichino, I.P.; Gomanova, M.I.; Milenysheva, L.I.; Yakovlev, A.I.

    1986-07-01

    The authors have studied the dynamics of the accumulation of polysaccharides in flaxseed plantain when it is given a foliar top dressing with molybdenum, and also their monosaccaride composition and physicochemical properties. The amounts of galacturonic acid were determined by potentiometric titration. The results of the investigations permit the conclusions that molybdenum somewhat decreases the amounts of total monosaccaride complex and of galacturonic acid while considerably raising the amount of -OCH/sub 3/.

  10. Cytochemical localization of calcium in cap cells of primary roots of Zea mays L

    NASA Technical Reports Server (NTRS)

    Moore, R.

    1986-01-01

    The distribution of calcium (Ca) in caps of vertically- and horizontally-oriented roots of Zea mays was monitored to determine its possible role in root graviresponsiveness. A modification of the antimonate precipitation procedure was used to localize Ca in situ. In vertically-oriented roots, the presumed graviperceptive (i.e., columella) cells were characterized by minimal and symmetric staining of the plasmalemma and mitochondria. No precipitate was present in plasmodesmata or cell walls. Within 5 min after horizontal reorientation, staining was associated with the portion of the cell wall adjacent to the distal end of the cell. This asymmetric staining persisted throughout the onset of gravicurvature. No staining of lateral cell walls of columella cells was observed at any stage of gravicurvature, suggesting that a lateral flow of Ca through the columella tissue of horizontally-oriented roots does not occur. The outermost peripheral cells of roots oriented horizontally and vertically secrete Ca through plasmodesmata-like structures in their cell walls. These results are discussed relative to proposed roles of root-cap Ca in root gravicurvature.

  11. PXRF, μ-XRF, vacuum μ-XRF, and EPMA analysis of Email Champlevé objects present in Belgian museums.

    PubMed

    Van der Linden, Veerle; Meesdom, Eva; Devos, Annemie; Van Dooren, Rita; Nieuwdorp, Hans; Janssen, Elsje; Balace, Sophie; Vekemans, Bart; Vincze, Laszlo; Janssens, Koen

    2011-10-01

    The enamel of 20 Email Champlevé objects dating between the 12th and 19th centuries was investigated by means of microscopic and portable X-ray fluorescence analysis (μ-XRF and PXRF). Seven of these objects were microsampled and the fragments were analyzed with electron probe microanalysis (EPMA) and vacuum μ-XRF to obtain quantitative data about the composition of the glass used to produce these enameled objects. As a result of the evolution of the raw materials employed to produce the base glass, three different compositional groups could be discriminated. The first group consisted of soda-lime-silica glass with a sodium source of mineral origin (with low K content) that was opacified by addition of calcium antimonate crystals. This type of glass was only used in objects made in the 12th century. Email Champlevé objects from the beginning of the 13th century onward were enameled with soda-lime-silica glass with a sodium source of vegetal origin. This type of glass, which has a higher potassium content, was opacified with SnO2 crystals. The glass used for 19th century Email Champlevé artifacts was produced with synthetic and purified components resulting in a different chemical composition compared to the other groups. Although the four analytical techniques employed in this study have their own specific characteristics, they were all found to be suitable for classifying the objects into the different chronological categories.

  12. Calcium and Calmodulin Localization in Gravitropically-responding Plant Organs

    NASA Technical Reports Server (NTRS)

    Roux, S. J.

    1985-01-01

    Antimonate staining procedures were used to detect calcium redistribution changes in corn roots. Results show that an asymmetric redistribution of Ca is induced by a gravitropic stimulus in roots as it is in shoots. Since this response occurs within 10 min, at least 5 min before any visible bending, it could play a role in the regulation of root gravitropism. Two different general approaches were used to localize calmodulin in plant tissue: radioimmunoassay of its content in tissue and in purified subcellular organelles, and immunocytochemical detection of it in roots and coleoptiles. Radioimmunoassay results indicate that calmodulin is present in large quantities in pllant cells and that it is specifically associated with mitochondria, etioplasts and nuclei. An assayed of an extract of soluble wall proteins revealed that over 1% of these proteins was calmodulin. Controls indicate that this calmodulin is not cytoplasmic in origin. A reaction product from anti-calmodulin was found mainly in the root cap cells, moderately in metazylem elements, in some cells in the stele surrounding metaxylem elements and in cortical cells.

  13. In vivo antileishmanial activity and chemical profile of polar extract from Selaginella sellowii

    PubMed Central

    Queiroz, Dayane Priscilla de Souza; Carollo, Carlos Alexandre; Kadri, Mônica Cristina Toffoli; Rizk, Yasmin Silva; de Araujo, Vanessa Carneiro Pereira; Monteiro, Paulo Eduardo de Oliveira; Rodrigues, Patrik Oening; Oshiro, Elisa Teruya; Matos, Maria de Fátima Cepa; de Arruda, Carla Cardozo Pinto

    2016-01-01

    The polar hydroethanolic extract from Selaginella sellowii(SSPHE) has been previously proven active on intracellular amastigotes (in vitro test) and now was tested on hamsters infected with Leishmania (Leishmania) amazonensis (in vivo test). SSPHE suppressed a 100% of the parasite load in the infection site and draining lymph nodes at an intralesional dose of 50 mg/kg/day × 5, which was similar to the results observed in hamsters treated with N-methylglucamine antimonate (Sb) (28 mg/Kg/day × 5). When orally administered, SSPHE (50 mg/kg/day × 20) suppressed 99.2% of the parasite load in infected footpads, while Sb suppressed 98.5%. SSPHE also enhanced the release of nitric oxide through the intralesional route in comparison to Sb. The chemical fingerprint of SSPHE by high-performance liquid chromatography with diode-array detection and tandem mass spectrometry showed the presence of biflavonoids and high molecular weight phenylpropanoid glycosides. These compounds may have a synergistic action in vivo. Histopathological study revealed that the intralesional treatment with SSPHE induced an intense inflammatory infiltrate, composed mainly of mononuclear cells. The present findings reinforce the potential of this natural product as a source of future drug candidates for American cutaneous leishmaniasis. PMID:26910353

  14. Amphotericin B lipid complex: in visceral leishmaniasis.

    PubMed

    Goldsmith, David R; Perry, Caroline M

    2004-01-01

    Amphotericin B lipid complex is a lipid formulation of amphotericin B, an antifungal drug with activity against Leishmania spp. Amphotericin B lipid complex appears to enhance uptake of amphotericin B by infected macrophages in patients with visceral leishmaniasis (VL). In randomised, open-label, dose-ranging studies, short-course treatment with once-daily amphotericin B lipid complex (5-15 mg/kg total cumulative dose over 5 days), administered by intravenous infusion, produced high rates of apparent (day 19) [93-100%] and definitive (6 months) [79-100%] cures in Indian patients with antimonial-resistant VL. Amphotericin B lipid complex appeared to be as effective as liposomal amphotericin B or the conventional deoxycholate formulation in a randomised, open-label study conducted in India in a mixed population of patients with previously untreated or antimonial-resistant VL. In patients with HIV infection and VL, amphotericin B lipid complex 3 mg/kg/day for 5 or 10 days appeared to be as effective as meglumine antimonate 20 mg/kg/day for 28 days in a small randomised pilot study in southern Europe. Amphotericin B lipid complex was generally well tolerated in patients with VL. Infusion-related reactions were the most common adverse events associated with amphotericin B lipid complex.

  15. Calcium transport mechanism in molting crayfish revealed by microanalysis

    SciTech Connect

    Mizuhira, V.; Ueno, M.

    1983-01-01

    Crayfish provide a good model in which to study the transport mechanism of Ca ions. During the molting stage, decalcified Ca ions are transferred into the blood and accumulate in the gastrolith epithelium, after which a gastrolith is formed on the surface of the epithelium. The gastrolith is dissolved in the stomach after molting, and the Ca is reabsorbed and redistributed throughout the newly formed exoskeleton. We studied the mechanism of Ca transport by cytochemical precipitation of Ca ions and by electron microanalysis, including X-ray microanalysis (EDX) and electron energy-loss spectroscopy (EELS), with a computer. In EDX analysis, the fine precipitates of K-antimonate in the gastrolith mitochondria clearly defined Ca with antimony; we also observed a large amount of Ca-oxalate in the mitochondria, and Ca-K X-ray pulses were clearly defined. Ca-K X-rays were also detected from fresh freeze-substituted mitochondria. Finally, we succeeded in taking a Ca-L EELS image from the mitochondria of fresh freeze-substituted thin sections. Only a very small amount of Ca was detected from the cell membrane and other organelles. Ca-adenosine triphosphatase (ATPase) and Mg-ATPase activity was also very clearly demonstrated in the mitochondria. These enzymes may play an important role in Ca metabolism.

  16. Composition and microstructure of maiolica from the museum of ceramics in Ascoli Piceno (Italy): evidences by electron microscopy and microanalysis

    NASA Astrophysics Data System (ADS)

    Gulmini, M.; Scognamiglio, F.; Roselli, G.; Vaggelli, G.

    2015-09-01

    The present work focuses on majolica objects from the collection of the museum of ceramic in Ascoli Piceno (Italy). The scientific investigation was performed on fragments detached from seven maiolicas attributed to the Castelli production (Abruzzi region) and one majolica from the Ascoli Piceno production (Marche region). The Castelli artifacts (late sixteenth-early eighteenth century) belong to the decorated style known as " compendiario." The piece from Ascoli Piceno recalls the decoration style of the other considered objects and is attributable to the "Paci" manufacture (first half of the nineteenth century). The selected objects were investigated by fiber optics reflectance spectroscopy, micro-X-ray fluorescence spectroscopy and scanning electron microscopy coupled with electron-dispersive X-ray spectrometry. The ceramic bodies of all objects are calcareous, whereas the glazes are lead-alkali type opacified by tin dioxide. Blue and purplish-red decorations were obtained by cobalt and manganese compounds dissolved in the glaze, respectively. Yellow and orange decorations were obtained by particles of lead antimonate and hematite. Finally, black decorations were obtained using compounds rich in manganese and iron. The study contributes to knowledge on the production of Castelli ceramics and presents first archaeometric data on the maiolica production from Ascoli Piceno. The scientific examination highlights continuity with the Renaissance production, and the joint contribution of the three analytical techniques suggests distinctive features among different productions, thus integrating and refining the information obtained by the art-historical study.

  17. Mechanisms of antimony adsorption onto soybean stover-derived biochar in aqueous solutions.

    PubMed

    Vithanage, Meththika; Rajapaksha, Anushka Upamali; Ahmad, Mahtab; Uchimiya, Minori; Dou, Xiaomin; Alessi, Daniel S; Ok, Yong Sik

    2015-03-15

    Limited mechanistic knowledge is available on the interaction of biochar with trace elements (Sb and As) that exist predominantly as oxoanions. Soybean stover biochars were produced at 300 °C (SBC300) and 700 °C (SBC700), and characterized by BET, Boehm titration, FT-IR, NMR and Raman spectroscopy. Bound protons were quantified by potentiometric titration, and two acidic sites were used to model biochar by the surface complexation modeling based on Boehm titration and NMR observations. The zero point of charge was observed at pH 7.20 and 7.75 for SBC300 and SBC700, respectively. Neither antimonate (Sb(V)) nor antimonite (Sb(III)) showed ionic strength dependency (0.1, 0.01 and 0.001 M NaNO3), indicating inner sphere complexation. Greater adsorption of Sb(III) and Sb(V) was observed for SBC300 having higher -OH content than SBC700. Sb(III) removal (85%) was greater than Sb(V) removal (68%). Maximum adsorption density for Sb(III) was calculated as 1.88 × 10(-6) mol m(-2). The Triple Layer Model (TLM) successfully described surface complexation of Sb onto soybean stover-derived biochar at pH 4-9, and suggested the formation of monodentate mononuclear and binuclear complexes. Spectroscopic investigations by Raman, FT-IR and XPS further confirmed strong chemisorptive binding of Sb to biochar surfaces.

  18. Kinetic modeling of antimony(V) adsorption-desorption and transport in soils.

    PubMed

    Zhang, Hua; Li, Lulu; Zhou, Shiwei

    2014-09-01

    Antimonate [Sb(V)] adsorption-desorption and transport in an acidic red soil (Yingtan) and a calcareous soil (Huanjiang) was investigated using kinetic batch and miscible displacement experiments. Different formulations of a multi-reaction model (MRM) were evaluated for their capabilities of describing the retention and transport mechanisms of Sb(V) in soils. The experimental results showed that adsorption of Sb(V) by two soils was kinetically controlled and largely irreversible. The Sb(V) adsorption capacity and kinetic rate of the acidic red soil was much higher than that of the calcareous soil. The asymmetrical breakthrough curves indicated the strong dominance of non-equilibrium retention of Sb(V). A four step sequential extraction procedure provided evidence that majority of applied Sb(V) was irreversibly retained. A formulation of MRM with two kinetic sorption sites (reversible and irreversible) successfully described Sb(V) adsorption-desorption data. The use of kinetic batch rate coefficients for predictions of breakthrough curves (BTCs) underestimated Sb(V) retention and overestimated its mobility. In an inverse mode with optimized rate coefficients, the MRM formulation was capable of simulating Sb(V) transport in soil columns.

  19. Chronic exposure to arsenic in drinking water can lead to resistance to antimonial drugs in a mouse model of visceral leishmaniasis.

    PubMed

    Perry, Meghan R; Wyllie, Susan; Raab, Andrea; Feldmann, Joerg; Fairlamb, Alan H

    2013-12-01

    The Indian subcontinent is the only region where arsenic contamination of drinking water coexists with widespread resistance to antimonial drugs that are used to treat the parasitic disease visceral leishmaniasis. We have previously proposed that selection for parasite resistance within visceral leishmaniasis patients who have been exposed to trivalent arsenic results in cross-resistance to the related metalloid antimony, present in the pentavalent state as a complex in drugs such as sodium stibogluconate (Pentostam) and meglumine antimonate (Glucantime). To test this hypothesis, Leishmania donovani was serially passaged in mice exposed to arsenic in drinking water at environmentally relevant levels (10 or 100 ppm). Arsenic accumulation in organs and other tissues was proportional to the level of exposure and similar to that previously reported in human liver biopsies. After five monthly passages in mice exposed to arsenic, isolated parasites were found to be completely refractory to 500 μg · mL(-1) Pentostam compared with the control passage group (38.5 μg · mL(-1)) cultured in vitro in mouse peritoneal macrophages. Reassessment of resistant parasites following further passage for 4 mo in mice without arsenic exposure showed that resistance was stable. Treatment of infected mice with Pentostam confirmed that resistance observed in vitro also occurred in vivo. We conclude that arsenic contamination may have played a significant role in the development of Leishmania antimonial resistance in Bihar because inadequate treatment with antimonial drugs is not exclusive to India, whereas widespread antimonial resistance is.

  20. Antimony (Sb) and arsenic (As) in Sb mining impacted paddy soil from Xikuangshan, China: differences in mechanisms controlling soil sequestration and uptake in rice.

    PubMed

    Okkenhaug, Gudny; Zhu, Yong-Guan; He, Junwen; Li, Xi; Luo, Lei; Mulder, Jan

    2012-03-20

    Foods produced on soils impacted by antimony (Sb) mining activities are a potential health risk due to plant uptake of the contaminant metalloids (Sb) and arsenic (As). Here we report for the first time the chemical speciation of Sb in soil and porewater of flooded paddy soil, impacted by active Sb mining, and its effect on uptake and speciation in rice plants (Oryza sativa L. cv Jiahua). Results are compared with behavior and uptake of As. Pot experiments were conducted under controlled conditions in a climate chamber over a period of 50 days. In pots without rice plants, flooding increased both the concentration of dissolved Sb (up to ca. 2000 μg L(-1)) and As (up to ca. 1500 μg L(-1)). When rice was present, Fe plaque developing on rice roots acted as a scavenger for both As and Sb, whereby the concentration of As, but not Sb, in porewater decreased substantially. Dissolved Sb in porewater, which occurred mainly as Sb(V), correlated with Ca, indicating a solubility governed by Ca antimonate. No significant differences in bioaccumulation factor and translocation factor between Sb and As were observed. Greater relative concentration of Sb(V) was found in rice shoots compared to rice root and porewater, indicating either a preferred uptake of Sb(V) or possibly an oxidation of Sb(III) to Sb(V) in shoots. Adding soil amendments (olivine, hematite) to the paddy soil had no effect on Sb and As concentrations in porewater. PMID:22309044

  1. Chronic exposure to arsenic in drinking water can lead to resistance to antimonial drugs in a mouse model of visceral leishmaniasis

    PubMed Central

    Perry, Meghan R.; Wyllie, Susan; Raab, Andrea; Feldmann, Joerg; Fairlamb, Alan H.

    2013-01-01

    The Indian subcontinent is the only region where arsenic contamination of drinking water coexists with widespread resistance to antimonial drugs that are used to treat the parasitic disease visceral leishmaniasis. We have previously proposed that selection for parasite resistance within visceral leishmaniasis patients who have been exposed to trivalent arsenic results in cross-resistance to the related metalloid antimony, present in the pentavalent state as a complex in drugs such as sodium stibogluconate (Pentostam) and meglumine antimonate (Glucantime). To test this hypothesis, Leishmania donovani was serially passaged in mice exposed to arsenic in drinking water at environmentally relevant levels (10 or 100 ppm). Arsenic accumulation in organs and other tissues was proportional to the level of exposure and similar to that previously reported in human liver biopsies. After five monthly passages in mice exposed to arsenic, isolated parasites were found to be completely refractory to 500 μg⋅mL−1 Pentostam compared with the control passage group (38.5 μg⋅mL−1) cultured in vitro in mouse peritoneal macrophages. Reassessment of resistant parasites following further passage for 4 mo in mice without arsenic exposure showed that resistance was stable. Treatment of infected mice with Pentostam confirmed that resistance observed in vitro also occurred in vivo. We conclude that arsenic contamination may have played a significant role in the development of Leishmania antimonial resistance in Bihar because inadequate treatment with antimonial drugs is not exclusive to India, whereas widespread antimonial resistance is. PMID:24167266

  2. A new method for antimony speciation in plant biomass and nutrient media using anion exchange cartridge.

    PubMed

    Tisarum, Rujira; Ren, Jing-Hua; Dong, Xiaoling; Chen, Hao; Lessl, Jason T; Ma, Lena Q

    2015-11-01

    A selective separation method based on anion exchange cartridge was developed to determine antimony (Sb) speciation in biological matrices by graphite furnace atomic absorption spectrophotometry (GFAAS). The selectivity of the cartridge towards antimonite [Sb(III)] and antimonate [Sb(V)] reversed in the presence of deionized (DI) water and 2mM citric acid. While Sb(V) was retained by the cartridge in DI water, Sb(III) was retained in citric acid media. At pH 6, Sb(III) and Sb(V) formed Sb(III)- and Sb(V)-citrate complexes, but the cartridge had higher affinity towards the Sb(III)-citrate complex. Separation of Sb(III) was tested at various concentrations in fresh and spent growth media and plant tissues. Our results showed that cartridge-based Sb speciation was successful in plant tissues, which was confirmed by HPLC-ICP-MS. The cartridge retained Sb(III) and showed 92-104% Sb(V) recovery from arsenic hyperaccumulator Pteris vittata roots treated with Sb(III) and Sb(V). The cartridge procedure is an effective alternative for Sb speciation, offering low cost, reproducible results, and simple Sb analysis using GFAAS. PMID:26452943

  3. In vivo antileishmanial activity and chemical profile of polar extract from Selaginella sellowii.

    PubMed

    Queiroz, Dayane Priscilla de Souza; Carollo, Carlos Alexandre; Kadri, Mônica Cristina Toffoli; Rizk, Yasmin Silva; Araujo, Vanessa Carneiro Pereira de; Monteiro, Paulo Eduardo de Oliveira; Rodrigues, Patrik Oening; Oshiro, Elisa Teruya; Matos, Maria de Fátima Cepa; Arruda, Carla Cardozo Pinto de

    2016-03-01

    The polar hydroethanolic extract from Selaginella sellowii(SSPHE) has been previously proven active on intracellular amastigotes (in vitro test) and now was tested on hamsters infected with Leishmania (Leishmania) amazonensis (in vivo test). SSPHE suppressed a 100% of the parasite load in the infection site and draining lymph nodes at an intralesional dose of 50 mg/kg/day × 5, which was similar to the results observed in hamsters treated with N-methylglucamine antimonate (Sb) (28 mg/Kg/day × 5). When orally administered, SSPHE (50 mg/kg/day × 20) suppressed 99.2% of the parasite load in infected footpads, while Sb suppressed 98.5%. SSPHE also enhanced the release of nitric oxide through the intralesional route in comparison to Sb. The chemical fingerprint of SSPHE by high-performance liquid chromatography with diode-array detection and tandem mass spectrometry showed the presence of biflavonoids and high molecular weight phenylpropanoid glycosides. These compounds may have a synergistic action in vivo. Histopathological study revealed that the intralesional treatment with SSPHE induced an intense inflammatory infiltrate, composed mainly of mononuclear cells. The present findings reinforce the potential of this natural product as a source of future drug candidates for American cutaneous leishmaniasis.

  4. A fruitful demonstration in sensors based on upconversion luminescence of Yb3+/Er3+codoped Sb2O3-WO3-Li2O (SWL) glass-ceramic

    NASA Astrophysics Data System (ADS)

    Prasad Sukul, Prasenjit; Kumar, Kaushal

    2016-07-01

    In this article, erbium and ytterbium doped lithium tungsten antimonate (Yb3+/Er3+:Sb2O3-WO3-Li2O) glass-ceramics (GC) is synthesized and its novel applications in temperature sensing and detection of latent fingerprints is studied. It is also estimated that this material could be useful as a solar cell concentrator. The upconversion emission studies on Yb3+/Er3+:SWL glass-ceramics have shown intense green emission at 525 nm (2H11/2 → 4I15/2) & 545 nm (4s3/2 → 4I15/2). The variation of UC intensities with external temperature have shown a well-fashioned pattern, which suggests that the 2H11/2 and 4S3/2 levels of Er3+ ion are thermally coupled and can act as a temperature sensor in the 300–500 K temperature range. Dry powder of Yb3+/Er3+:SWL glass-ceramic is used to develop latent fingerprint with high contrast in green color on glass slide.

  5. High antiferromagnetic transition temperature of a honeycomb compound SrRu2O6

    DOE PAGESBeta

    Tian, Wei; Svoboda, Chris; Ochi, M.; Matsuda, M.; Cao, Huibo; Cheng, J. -G.; Sales, B. C.; Mandrus, D.; Arita, R.; Trivedi, Nandini; et al

    2015-09-14

    We study the high-temperature magnetic order in a quasi-two-dimensional honeycomb compound SrRu2O6 by measuring magnetization and neutron powder diffraction with both polarized and unpolarized neutrons. SrRu2O6 crystallizes into the hexagonal lead antimonate (PbSb2O6, space group P31m) structure with layers of edge-sharing RuO6 octahedra separated by Sr2+ ions. SrRu2O6 is found to order at TN = 565 K with Ru moments coupled antiferromagnetically both in plane and out of plane. The magnetic moment is 1.30(2) μB/Ru at room temperature and is along the crystallographic c axis in the G-type magnetic structure. We perform density functional calculations with constrained random-phase approximation (RPA)more » to obtain the electronic structure and effective intra- and interorbital interaction parameters. The projected density of states shows strong hybridization between Ru 4d and O 2p. By downfolding to the target t2g bands we extract the effective magnetic Hamiltonian and perform Monte Carlo simulations to determine the transition temperature as a function of interand intraplane couplings. We find a weak interplane coupling, 3% of the strong intraplane coupling, permits three-dimensional magnetic order at the observed TN .« less

  6. A new method for antimony speciation in plant biomass and nutrient media using anion exchange cartridge.

    PubMed

    Tisarum, Rujira; Ren, Jing-Hua; Dong, Xiaoling; Chen, Hao; Lessl, Jason T; Ma, Lena Q

    2015-11-01

    A selective separation method based on anion exchange cartridge was developed to determine antimony (Sb) speciation in biological matrices by graphite furnace atomic absorption spectrophotometry (GFAAS). The selectivity of the cartridge towards antimonite [Sb(III)] and antimonate [Sb(V)] reversed in the presence of deionized (DI) water and 2mM citric acid. While Sb(V) was retained by the cartridge in DI water, Sb(III) was retained in citric acid media. At pH 6, Sb(III) and Sb(V) formed Sb(III)- and Sb(V)-citrate complexes, but the cartridge had higher affinity towards the Sb(III)-citrate complex. Separation of Sb(III) was tested at various concentrations in fresh and spent growth media and plant tissues. Our results showed that cartridge-based Sb speciation was successful in plant tissues, which was confirmed by HPLC-ICP-MS. The cartridge retained Sb(III) and showed 92-104% Sb(V) recovery from arsenic hyperaccumulator Pteris vittata roots treated with Sb(III) and Sb(V). The cartridge procedure is an effective alternative for Sb speciation, offering low cost, reproducible results, and simple Sb analysis using GFAAS.

  7. A fruitful demonstration in sensors based on upconversion luminescence of Yb3+/Er3+codoped Sb2O3-WO3-Li2O (SWL) glass-ceramic

    NASA Astrophysics Data System (ADS)

    Prasad Sukul, Prasenjit; Kumar, Kaushal

    2016-07-01

    In this article, erbium and ytterbium doped lithium tungsten antimonate (Yb3+/Er3+:Sb2O3-WO3-Li2O) glass-ceramics (GC) is synthesized and its novel applications in temperature sensing and detection of latent fingerprints is studied. It is also estimated that this material could be useful as a solar cell concentrator. The upconversion emission studies on Yb3+/Er3+:SWL glass-ceramics have shown intense green emission at 525 nm (2H11/2 → 4I15/2) & 545 nm (4s3/2 → 4I15/2). The variation of UC intensities with external temperature have shown a well-fashioned pattern, which suggests that the 2H11/2 and 4S3/2 levels of Er3+ ion are thermally coupled and can act as a temperature sensor in the 300-500 K temperature range. Dry powder of Yb3+/Er3+:SWL glass-ceramic is used to develop latent fingerprint with high contrast in green color on glass slide.

  8. Polychrome glass from Etruscan sites: first non-destructive characterization with synchrotron μ-XRF, μ-XANES and XRPD

    NASA Astrophysics Data System (ADS)

    Arletti, R.; Vezzalini, G.; Quartieri, S.; Ferrari, D.; Merlini, M.; Cotte, M.

    2008-07-01

    This work is devoted to the characterization of a suite of very rare, highly decorated and coloured glass vessels and beads from the VII to the IV century BC. The most serious difficulty in developing this study was that any sampling even micro-sampling was absolutely forbidden. As a consequence, the mineralogical and chemical nature of chromophores and opacifiers present in these Iron Age finds were identified by means of the following synchrotron-based, strictly non-destructive, techniques: micro X-ray fluorescence (μ-XRF), Fe K-edge micro X-ray absorption near edge spectroscopy (μ-XANES) and X-ray powder diffraction (XRPD). The μ-XRF mapping evidenced high levels of Pb and Sb in the yellow decorations and the presence of only Sb in the white and light-blue ones. Purple and black glass show high amounts of Mn and Fe, respectively. The XRPD analyses confirmed the presence of lead and calcium antimonates in yellow, turquoise and white decorations. Fe K-edge μ-XANES spectra were collected in different coloured parts of the finds, thus enabling the mapping of the oxidation state of these elements across the samples. In most of the samples iron is present in the reduced form Fe2+ in the bulk glass of the vessels, and in the oxidized form Fe3+ in the decorations, indicating that these glass artefacts were produced in at least two distinct processing steps under different furnace conditions.

  9. Photoassisted reduction of molecular oxygen to hydrogen peroxide catalyzed by oxoalkoxomolybdenum(V) porphyrin

    SciTech Connect

    Ledon, H.J.; Bonnet, M.; Galland, D.

    1981-10-07

    Formation of the oxomolybdenum (IV) porphyrin O = M/sub 0//sup IV/(TPP)-OCH/sub 3/(2), by photoinduced hemolysis of the Mo-OCH/sub 3/ bond was confirmed by EPR spectroscopy and spin-trapping experiments. When an oxygen-free benzene solution of 0 = M/sub 0//sup V/(TPP)-OCH/sub 3/(1) was irradiated directly in the cavity of an EPR spectrometer, the intensity of the characteristic nine-line spectra of 1 slowly diminished with time but again was fully restored when the cell was open to air and one drop of methanol was added, confirming the formation of a diamagnetic molybdoporphyrin complex upon irradiation. The reoxidation of O = Mo/sup IV/(TPP)(2) in a benzene-methanol mixture was monitored by uv-visible spectrometry, which showed the reaction to follow strict second-order kinetics. This second dependence on molybdenum suggests a two-electron reduction of molecular oxygen to hydrogen peroxide which was actually identified in separate experiments. In order to evaluate the efficiency and possible uses of the photoreduction of 1, a catalytic cycle was devised by coupling the reactions described. The results of these studies clearly established the ability of molybdenum porphyrins to harvest solar energy to produce reactive intermediates by redox processes.

  10. Co-occurrence of a cerebral cavernous malformation and an orbital cavernous hemangioma in a patient with seizures and visual symptoms: Rare crossroads for vascular malformations

    PubMed Central

    Choudhri, Omar; Feroze, Abdullah H.; Lad, Eleonora M.; Kim, Jonathan W.; Plowey, Edward D.; Karamchandani, Jason R.; Chang, Steven D.

    2014-01-01

    Background: Cerebral cavernous malformations (CCMs) are angiographically occult vascular malformations of the central nervous system. As a result of hemorrhage and mass effect, patients may present with focal neurologic deficits, seizures, and other symptoms necessitating treatment. Once symptomatic, most often from hemorrhage, CCMs are treated with microsurgical resection. Orbital cavernous hemangiomas (OCHs) are similar but distinct vascular malformations that present within the orbital cavity. Even though CCMs and OCHs are both marked by dilated endothelial-lined vascular channels, they are infrequently seen in the same patient. Case Description: We provide a brief overview of the two related pathologies in the context of a patient presenting to our care with concomitant lesions, which were both resected in full without complication. Conclusion: This is the first known report that describes a case of concomitant CCM and OCH and explores the origins of two pathologies that are rarely encountered together in neurosurgical practice. Recognition of disparate symptomatologies is important for properly managing these patients. PMID:25071938

  11. Cross-conjugated hexaphyrins and their bis-rhodium complexes.

    PubMed

    Naoda, Koji; Sung, Young Mo; Lim, Jong Min; Kim, Dongho; Osuka, Atsuhiro

    2014-06-16

    A cross-conjugated hexaphyrin that carries two meso-oxacyclohexadienylidenyl (OCH) groups 9 was synthesized from the condensation of 5,10-bis(pentafluorophenyl)tripyrrane with 3,5-di-tert-butyl-4-hydroxybenzaldehyde. The reduction of 9 with NaBH4 afforded the Möbius aromatic [28]hexaphyrin 10. Bis-rhodium complex 11, prepared from the reaction of 10 with [{RhCl(CO)2}2], displays strong Hückel antiaromatic character because of the 28 π electrons that occupy the conjugated circuit on the enforced planar structure. The oxidation of 11 with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) yielded complexes 12 and 13 depending upon the reaction conditions. Both 12 and 13 are planar owing to bis-rhodium metalation. Although complex 12 bears two meso-OCH groups at the long sides and is quinonoidal and nonaromatic in nature, complex 13 bears 3,5-di-tert-butyl-4-hydroxyphenyl and OCH groups and exhibits a moderate diatropic ring current despite its cross-conjugated electronic circuit. The diatropic ring current increases upon increasing the solvent polarity, most likely due to an increased contribution of an aromatic zwitterionic resonance hybrid. PMID:24805261

  12. Photoelectron velocity-map imaging spectroscopic and theoretical study on the reactivity of the gold atom toward CH3SH, CH3OH, and H2O.

    PubMed

    Qin, Zhengbo; Cong, Ran; Wu, Xia; Liu, Zhiling; Xie, Hua; Tang, Zichao; Jiang, Ling; Fan, Hongjun

    2013-07-21

    Photoelectron velocity-map imaging spectroscopy has been used to study the reaction of the anionic gold atom with the HR (R = SCH3, OCH3, OH) molecules. The solvated [Au···HR](-) and inserted [HAuR](-) products have been experimentally observed for R = SCH3, whereas only solvated [Au⋯HR](-) products were found for R = OCH3 and OH. This significant difference in the photoelectron spectra suggests the different reactivity of the Au(-) toward the CH3SH, CH3OH, and H2O molecules. Second order Møller-Plesset perturbation theory and coupled-cluster single double triple excitation calculations have been performed to aid the structural assignment of the spectra and to explore the reaction mechanism. Activation energies for the isomerizations of the solvated structures to the inserted ones in the Au(-)∕Au + HR reactions (R = OCH3 and OH) are predicted to be much higher than those for the Au(-)∕Au + CH3SH reactions, supporting the experimental observation. Theoretical calculations provide the evidence that the intriguing [HAuSCH3](-) product may be formed by the attachment of the electron onto the neutral HAuSCH3 species or the isomerization from the anionic [Au···HSCH3](-) one. These findings should be helpful for understanding the feature that the thiols are able to form the staple motifs, whereas CH3OH and H2O are not.

  13. Synthesis and characterisation of new types of side chain cholesteryl polymers.

    PubMed

    Wang, Bin; Du, Haiyan; Zhang, Junhua

    2011-01-01

    A series of cholesterol derivatives have been synthesised via the alkylation reaction of the 3-hydroxyl group with the aliphatic bromide compounds with different chain lengths, namely 3β-alkyloxy-cholesterol. The double bond between the C5 and C6 positions in these cholesterol derivatives was oxidised into epoxy, followed by an epoxy-ring-opening reaction with the treatment with acrylic acid, resulting in a series of 3β-alkyloxy-5α-hydroxy-6β-acryloyloxycholesterol, C(n)OCh (n=1, 2, 4, 6, 8, 10, 12), The acrylate group is connected to the C6 position, which is confirmed by the single crystal structure analysis. The corresponding polymers, PC(n)OCh, were prepared via free radical polymerisation. The structure of monomers and the resulting polymers were characterised with nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). The thermal properties of PC(n)OCh were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). To determine the secondary structure of polymers, circular dichroism (CD) spectra were performed. It was found that not all monomers produce high-molecular-weight polymers because of steric hindrance. However, all polymers have a helical structure, which can be enhanced by increasing the alkoxy chain length. In addition, increasing the alkoxy chain length decreases the glass transition temperature and increases the decomposition temperature of the polymers. PMID:21070795

  14. Methyl-perfluoroheptene-ethers (CH3OC7F13): measured OH radical reaction rate coefficients for several isomers and enantiomers and their atmospheric lifetimes and global warming potentials.

    PubMed

    Jubb, Aaron M; Gierczak, Tomasz; Baasandorj, Munkhbayar; Waterland, Robert L; Burkholder, James B

    2014-05-01

    Mixtures of methyl-perfluoroheptene-ethers (CH3OC7F13, MPHEs) are currently in use as replacements for perfluorinated alkanes (PFCs) and poly-ether heat transfer fluids, which are persistent greenhouse gases with lifetimes >1000 years. At present, the atmospheric processing and environmental impact from the use of MPHEs is unknown. In this work, rate coefficients at 296 K for the gas-phase reaction of the OH radical with six key isomers (including stereoisomers and enantiomers) of MPHEs used commercially were measured using a relative rate method. Rate coefficients for the six MPHE isomers ranged from ∼ 0.1 to 2.9 × 10(-12) cm(3) molecule(-1) s(-1) with a strong stereoisomer and -OCH3 group position dependence; the (E)-stereoisomers with the -OCH3 group in an α- position relative to the double bond had the greatest reactivity. Rate coefficients measured for the d3-MPHE isomer analogues showed decreased reactivity consistent with a minor contribution of H atom abstraction from the -OCH3 group to the overall reactivity. Estimated atmospheric lifetimes for the MPHE isomers range from days to months. Atmospheric lifetimes, radiative efficiencies, and global warming potentials for these short-lived MPHE isomers were estimated based on the measured OH rate coefficients along with measured and theoretically calculated MPHE infrared absorption spectra. Our results highlight the importance of quantifying the atmospheric impact of individual components in an isomeric mixture.

  15. Solid Electrolyte Interphase Growth and Capacity Loss in Silicon Electrodes.

    PubMed

    Michan, Alison L; Divitini, Giorgio; Pell, Andrew J; Leskes, Michal; Ducati, Caterina; Grey, Clare P

    2016-06-29

    The solid electrolyte interphase (SEI) of the high capacity anode material Si is monitored over multiple electrochemical cycles by (7)Li, (19)F, and (13)C solid-state nuclear magnetic resonance spectroscopies, with the organics dominating the SEI. Homonuclear correlation experiments are used to identify the organic fragments -OCH2CH2O-, -OCH2CH2-, -OCH2CH3, and -CH2CH3 contained in both oligomeric species and lithium semicarbonates ROCO2Li, RCO2Li. The SEI growth is correlated with increasing electrode tortuosity by using focused ion beam and scanning electron microscopy. A two-stage model for lithiation capacity loss is developed: initially, the lithiation capacity steadily decreases, Li(+) is irreversibly consumed at a steady rate, and pronounced SEI growth is seen. Later, below 50% of the initial lithiation capacity, less Si is (de)lithiated resulting in less volume expansion and contraction; the rate of Li(+) being irreversibly consumed declines, and the Si SEI thickness stabilizes. The decreasing lithiation capacity is primarily attributed to kinetics, the increased electrode tortuousity severely limiting Li(+) ion diffusion through the bulk of the electrode. The resulting changes in the lithiation processes seen in the electrochemical capacity curves are ascribed to non-uniform lithiation, the reaction commencing near the separator/on the surface of the particles.

  16. Duplex stabilities of phosphorothioate, methylphosphonate, and RNA analogs of two DNA 14-mers.

    PubMed Central

    Kibler-Herzog, L; Zon, G; Uznanski, B; Whittier, G; Wilson, W D

    1991-01-01

    The duplex stabilities of various phosphorothioate, methylphosphonate, RNA and 2'-OCH3 RNA analogs of two self-complementary DNA 14-mers are compared. Phosphorothioate and/or methylphosphonate analogs of the two sequences d(TAATTAATTAATTA) [D1] and d(TAGCTAATTAGCTA) [D2] differ in the number, position, or chirality (at the 5' terminal linkage) of the modified phosphates. Phosphorothioate derivatives of D1 are found to be less destabilized when the linkage modified is between adenines rather than between thymines. Surprisingly, no base sequence effect on duplex stabilization is observed for any methylphosphonate derivatives of D1 or D2. Highly modified phosphorothioates or methylphosphonates are less stable than their partially modified counterparts which are less stable than the unmodified parent compounds. The 'normal' (2'-OH) RNA analog of duplex D1 is slightly destabilized, whereas the 2'-OCH3 RNA derivative is significantly stabilized relative to the unmodified DNA. For the D1 sequence, at approximately physiological salt concentration, the order of duplex stability is 2'-OCH3 RNA greater than unmodified DNA greater than 'normal' RNA greater than methylphosphonate DNA greater than phosphorothioate DNA. D2 and the various D2 methylphosphonate analogs investigated all formed hairpin conformations at low salt concentrations. PMID:1711677

  17. Synthesis and characterisation of new types of side chain cholesteryl polymers.

    PubMed

    Wang, Bin; Du, Haiyan; Zhang, Junhua

    2011-01-01

    A series of cholesterol derivatives have been synthesised via the alkylation reaction of the 3-hydroxyl group with the aliphatic bromide compounds with different chain lengths, namely 3β-alkyloxy-cholesterol. The double bond between the C5 and C6 positions in these cholesterol derivatives was oxidised into epoxy, followed by an epoxy-ring-opening reaction with the treatment with acrylic acid, resulting in a series of 3β-alkyloxy-5α-hydroxy-6β-acryloyloxycholesterol, C(n)OCh (n=1, 2, 4, 6, 8, 10, 12), The acrylate group is connected to the C6 position, which is confirmed by the single crystal structure analysis. The corresponding polymers, PC(n)OCh, were prepared via free radical polymerisation. The structure of monomers and the resulting polymers were characterised with nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FT-IR) and gel permeation chromatography (GPC). The thermal properties of PC(n)OCh were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). To determine the secondary structure of polymers, circular dichroism (CD) spectra were performed. It was found that not all monomers produce high-molecular-weight polymers because of steric hindrance. However, all polymers have a helical structure, which can be enhanced by increasing the alkoxy chain length. In addition, increasing the alkoxy chain length decreases the glass transition temperature and increases the decomposition temperature of the polymers.

  18. Substituent effects on hydrogen bonding of aromatic amide-carboxylate.

    PubMed

    Sen, Ibrahim; Kara, Hulya; Azizoglu, Akın

    2016-10-01

    N-(p-benzoyl)-anthranilic acid (BAA) derivatives have been synthesized with different substituents (X: Br, Cl, OCH3, CH3), and their crystal structures have been analyzed in order to understand the variations in their molecular geometries with respect to the substituents by using (1)H NMR, (13)C NMR, IR and X-ray single-crystal diffraction. The carboxylic acid group forms classic OH⋯O hydrogen bonded dimers in a centrosymmetric R2(2)(8) ring motifs for BAA-Br and BAA-Cl. However, no carboxylic acid group forms classic OH⋯O hydrogen bonded dimers in BAA-OCH3 and BAA-CH3. The asymmetric unit consists of two crystallographically independent molecules in BAA-OCH3. DFT computations show that the interaction energies between monomer and dimer are in the range of 0.5-3.8kcal/mol with the B3LYP/6-31+G*, B3LYP/6-31++G*, B3LYP/6-31++G**, and B3LYP/AUG-cc-pVDZ levels of theory. The presence of different hydrogen bond patterns is also governed by the substrate. For monomeric compounds studied herein, theoretical calculations lead to two low-energy conformers; trans (a) and cis (b). Former one is more stable than latter by about 4kcal/mol. PMID:27239947

  19. Solid Electrolyte Interphase Growth and Capacity Loss in Silicon Electrodes.

    PubMed

    Michan, Alison L; Divitini, Giorgio; Pell, Andrew J; Leskes, Michal; Ducati, Caterina; Grey, Clare P

    2016-06-29

    The solid electrolyte interphase (SEI) of the high capacity anode material Si is monitored over multiple electrochemical cycles by (7)Li, (19)F, and (13)C solid-state nuclear magnetic resonance spectroscopies, with the organics dominating the SEI. Homonuclear correlation experiments are used to identify the organic fragments -OCH2CH2O-, -OCH2CH2-, -OCH2CH3, and -CH2CH3 contained in both oligomeric species and lithium semicarbonates ROCO2Li, RCO2Li. The SEI growth is correlated with increasing electrode tortuosity by using focused ion beam and scanning electron microscopy. A two-stage model for lithiation capacity loss is developed: initially, the lithiation capacity steadily decreases, Li(+) is irreversibly consumed at a steady rate, and pronounced SEI growth is seen. Later, below 50% of the initial lithiation capacity, less Si is (de)lithiated resulting in less volume expansion and contraction; the rate of Li(+) being irreversibly consumed declines, and the Si SEI thickness stabilizes. The decreasing lithiation capacity is primarily attributed to kinetics, the increased electrode tortuousity severely limiting Li(+) ion diffusion through the bulk of the electrode. The resulting changes in the lithiation processes seen in the electrochemical capacity curves are ascribed to non-uniform lithiation, the reaction commencing near the separator/on the surface of the particles. PMID:27232540

  20. Fluorine in drug design: a case study with fluoroanisoles.

    PubMed

    Xing, Li; Blakemore, David C; Narayanan, Arjun; Unwalla, Ray; Lovering, Frank; Denny, R Aldrin; Zhou, Huanyu; Bunnage, Mark E

    2015-04-01

    Anisole and fluoroanisoles display distinct conformational preferences, as evident from a survey of their crystal structures. In addition to altering the free ligand conformation, various degrees of fluorination have a strong impact on physicochemical and pharmacokinetic properties. Analysis of anisole and fluoroanisole matched molecular pairs in the Pfizer corporate database reveals interesting trends: 1) PhOCF3 increases log D by ~1 log unit over PhOCH3 compounds; 2) PhOCF3 shows lower passive permeability despite its higher lipophilicity; and 3) PhOCF3 does not appreciably improve metabolic stability over PhOCH3 . Emerging from the investigation, difluoroanisole (PhOCF2 H) strikes a better balance of properties with noticeable advantages of log D and transcellular permeability over PhOCF3 . Synthetic assessment illustrates that the routes to access difluoroanisoles are often more straightforward than those for trifluoroanisoles. Whereas replacing PhOCH3 with PhOCF3 is a common tactic to optimize ADME properties, our analysis suggests PhOCF2 H may be a more attractive alternative, and greater exploitation of this motif is recommended.

  1. Substituent effects on hydrogen bonding of aromatic amide-carboxylate

    NASA Astrophysics Data System (ADS)

    Sen, Ibrahim; Kara, Hulya; Azizoglu, Akın

    2016-10-01

    N-(p-benzoyl)-anthranilic acid (BAA) derivatives have been synthesized with different substituents (X: Br, Cl, OCH3, CH3), and their crystal structures have been analyzed in order to understand the variations in their molecular geometries with respect to the substituents by using 1H NMR, 13C NMR, IR and X-ray single-crystal diffraction. The carboxylic acid group forms classic Osbnd H ⋯ O hydrogen bonded dimers in a centrosymmetric R22(8) ring motifs for BAA-Br and BAA-Cl. However, no carboxylic acid group forms classic Osbnd H ⋯ O hydrogen bonded dimers in BAA-OCH3 and BAA-CH3. The asymmetric unit consists of two crystallographically independent molecules in BAA-OCH3. DFT computations show that the interaction energies between monomer and dimer are in the range of 0.5-3.8 kcal/mol with the B3LYP/6-31 + G*, B3LYP/6-31 ++G*, B3LYP/6-31 ++G**, and B3LYP/AUG-cc-pVDZ levels of theory. The presence of different hydrogen bond patterns is also governed by the substrate. For monomeric compounds studied herein, theoretical calculations lead to two low-energy conformers; trans (a) and cis (b). Former one is more stable than latter by about 4 kcal/mol.

  2. Saccharomyces Cerevisiae Hoc1, a Suppressor of Pkc1, Encodes a Putative Glycosyltransferase

    PubMed Central

    Neiman, A. M.; Mhaiskar, V.; Manus, V.; Galibert, F.; Dean, N.

    1997-01-01

    The Saccharomyces cerevisiae gene PKC1 encodes a protein kinase C isozyme that regulates cell wall synthesis. Here we describe the characterization of HOC1, a gene identified by its ability to suppress the cell lysis phenotype of pkc1-371 cells. The HOC1 gene (Homologous to OCH1) is predicted to encode a type II integral membrane protein that strongly resembles Och1p, an α-1,6-mannosyltransferase. Immunofluorescence studies localized Hoc1p to the Golgi apparatus. While overexpression of HOC1 rescued the pkc1-371 temperature-sensitive cell lysis phenotype, disruption of HOC1 lowered the restrictive temperature of the pkc1-371 allele. Disruption of HOC1 also resulted in hypersensitivity to Calcofluor White and hygromycin B, phenotypes characteristic of defects in cell wall integrity and protein glycosylation, respectively. The function of HOC1 appears to be distinct from that of OCH1. Taken together, these results suggest that HOC1 encodes a Golgi-localized putative mannosyltransferase required for the proper construction of the cell wall. PMID:9055074

  3. Comments on the ring-opening polymerization of morpholine-2,5-dione derivatives by various metal catalysts and characterization of the products formed in the reactions involving R2SnX2, where X = OPr(i) and NMe2 and R = Bu(n), Ph and p-Me2NC6H4.

    PubMed

    Chisholm, M H; Galucci, J; Krempner, C; Wiggenhorn, C

    2006-02-14

    (3S,6S)-3-Isopropyl-6-methyl-morpholine-2,5-dione (1), and (3S,6S)-3,6-dimethyl-morpholine-2,5-dione (2), do not enter into ring-opening polymerization reactions with metal catalyst precursors commonly employed for lactides, and with Sn(II) octanoate, only low molecular weight oligomers are obtained. Reactions with R2SnX2 compounds, where R = Ph, Bu(n) and p-Me2NC6H4 and X = OPr(i) or NMe2, reveal that ring-opening of the morpholine-2,5-diones does occur, but that polymerization is terminated by the formation of kinetically-inert products such as {Ph2Sn[mu,eta(3)-OCH(Me)CONCH(Pr(i))COOPr(i)]}2 (3), and {[Bu(n))2Sn[mu,eta(3)-OCH(Me)CONCH(Me)CONMe2]}2 (4), with elimination of HX. Ph3SnOPr(i) is seen to react reversibly with morpholine-2,5-diones in toluene-d8 by 1H NMR spectroscopy while (Bu(n))3SnNMe2 reacts by ring opening to give (Bu(n))3SnOCH(Me)C(O)NHCHMeC(O)NMe2. The new organotin compounds have been characterized by 1H, 13C{1H} and 118Sn NMR spectroscopy and compounds 1, 2, 3 and 4 by single crystal X-ray crystallography.

  4. [Dependence of the operation stress degree from the kind of operative intervention for an acute cholecystitis in the patients with high operative-anesthesiological risk].

    PubMed

    Bezruchko, M V; Malyk, S V; Kravchenko, S P; Osipov, O S; Sytnik, D A

    2013-03-01

    The results of comparison between the operation stress degree in various kinds of surgical interventions, performed for an acute cholecystitis, using determination of cortizol, prolactin and glucose content before the operation, intraoperatively and postoperatively in 50 patients, are adduced. There was established, that the largest (in 5.3 times) and the most durable (more than 24 hours) intr erative raising of the cortizol level in the blood serum was noted in patients, to whom open cholecystectomy (OCH) was done, and the minimal (in 2.2 times) and the least durable (up to 1 hour)--while performing transcutaneous transhepatic draining (TTD) of gallbladder under ultrasonographic control. While performance of laparoscopic cholecystectomy (LCH) there was noted the most pronounced intraoperative raising of prolactin level (in 3.6 times) and more rapid its lowering (during 24 hours) in comparison with such while the OCH performance (during 72 hours). In TTD there was observed the minimal intraoperative inhancing of the prolactin level (in 2.3 times) and its duration (during 1 hour) postoperatively. The above mentioned have witnessed, that while TTD of gallbladder performance stimulation of the anterior hypophysis is significantly lesser, than while LCH and OCH.

  5. Preparation and characterization of oligochitosan-tragacanth nanoparticles as a novel gene carrier.

    PubMed

    Fattahi, Ali; Sadrjavadi, Komail; Golozar, Mohammad Ali; Varshosaz, Jaleh; Fathi, Mohammad-Hossein; Mirmohammad-Sadeghi, Hamid

    2013-09-12

    The nanoparticles of oligochitosan-water soluble tragacanth (OCH-WST) as novel gene carriers have been prepared and their transfection efficiency has been investigated on Hela and HepG2 cell lines. Different OCH:WST weight ratios were prepared to obtain particles with low size distribution and high surface charge, and also in range of below 200 nm. Nanoparticles with 132.5 ± 6.77 nm size, polydispersity index 1.92 ± 0.061, surface charge 30.45 ± 1.84 and spherical morphology, have been chosen as gene carrier. Nanoparticle-DNA complexes (nanoplexes) showed better transfection efficiency in both Hela and HepG2 cells than chitosan polyplexes, with 1.26 × 10(6) versus 9.05 × 10(5) and 7.76 × 10(5) versus 2.16 × 10(5), respectively. Higher transfection efficiency of nanoplexes could be attributed to their weaker complexation. Decreasing of transfection in presence of galactose in HepG2 cells, indicated receptor mediated endocytosis of nanoplexes. These properties all together, make OCH-WST nanoparticles as potential gene carrier for active gene delivery into cells containing sugar receptors.

  6. Comments on the ring-opening polymerization of morpholine-2,5-dione derivatives by various metal catalysts and characterization of the products formed in the reactions involving R2SnX2, where X = OPr(i) and NMe2 and R = Bu(n), Ph and p-Me2NC6H4.

    PubMed

    Chisholm, M H; Galucci, J; Krempner, C; Wiggenhorn, C

    2006-02-14

    (3S,6S)-3-Isopropyl-6-methyl-morpholine-2,5-dione (1), and (3S,6S)-3,6-dimethyl-morpholine-2,5-dione (2), do not enter into ring-opening polymerization reactions with metal catalyst precursors commonly employed for lactides, and with Sn(II) octanoate, only low molecular weight oligomers are obtained. Reactions with R2SnX2 compounds, where R = Ph, Bu(n) and p-Me2NC6H4 and X = OPr(i) or NMe2, reveal that ring-opening of the morpholine-2,5-diones does occur, but that polymerization is terminated by the formation of kinetically-inert products such as {Ph2Sn[mu,eta(3)-OCH(Me)CONCH(Pr(i))COOPr(i)]}2 (3), and {[Bu(n))2Sn[mu,eta(3)-OCH(Me)CONCH(Me)CONMe2]}2 (4), with elimination of HX. Ph3SnOPr(i) is seen to react reversibly with morpholine-2,5-diones in toluene-d8 by 1H NMR spectroscopy while (Bu(n))3SnNMe2 reacts by ring opening to give (Bu(n))3SnOCH(Me)C(O)NHCHMeC(O)NMe2. The new organotin compounds have been characterized by 1H, 13C{1H} and 118Sn NMR spectroscopy and compounds 1, 2, 3 and 4 by single crystal X-ray crystallography. PMID:16437180

  7. Reactions of Monomeric [1,2,4-(Me3C)3C5H2]2CeH and CO with orwithout H2:An Experimental and Computational Study

    SciTech Connect

    Werkema, Evan L.; Maron, Laurent; Eisenstein, Odile; Andersen,Richard A.

    2006-09-07

    Addition of CO to [1,2,4-(Me3C)3C5H2]2CeH, Cp'2CeH, intoluene yields the cis (Cp'2Ce)2(mu-OCHCHO), in which the cis enediolategroup bridges the two metallocene fragments. The cis enediolatequantitatively isomerizes intramolecularly to the trans-enediolate inC6D6 at 100oC over seven months. When the solvent is pentane,Cp'2Ce(OCH2)CeCp'2 forms, in which the oxomethylene group or theformaldehyde dianion bridges the two metallocene fragments. The cisenediolate is suggested to form by insertion of CO into the Ce-C bond ofCp'2Ce(OCH2)CeCp'2 generating Cp'2CeOCH2COCeCp'2. The stereochemistry ofthe cis-enediolate is determined by a 1,2-hydrogen shift in the OCH2COfragment that has the OC(H2) bond anti periplanar relative to the carbenelone pair. The bridging oxomethylene complex reacts with H2, but not withCH4, to give Cp'2CeOMe, which is also the product of the reaction betweenCp'2CeH and a mixture of CO and H2. The oxomethylene complex reacts withCO to give the cis enediolate complex. DFT calculations on C5H5 modelmetallocenes show that the reaction of Cp2CeH with CO and H2 to giveCp2CeOMe is exoergic by 50 kcal mol-1. The net reaction proceeds by aseries of elementary reactions that occur after the formyl complex,Cp2Ce(eta-2 CHO), is formed by further reaction with H2. The key pointthat emerges from the calculated potential energy surface is thebifunctional nature of the metal formyl in which the carbon atom behavesas a donor and acceptor. Replacing H2 by CH4 increases the activationenergy barrier by 17 kcal mol-1.

  8. Direct Formation of the C5′-Radical in the Sugar-Phosphate Backbone of DNA by High Energy Radiation

    PubMed Central

    Adhikary, Amitava; Becker, David; Palmer, Brian J.; Heizer, Alicia N.; Sevilla, Michael D.

    2012-01-01

    Neutral sugar radicals formed in DNA sugar-phosphate backbone are well-established as precursors of biologically important damage such as DNA-strand scission and crosslinking. In this work, we present electron spin resonance (ESR) evidence showing that the sugar radical at C5′ (C5′•) is one of the most abundant (ca. 30%) sugar radicals formed by γ- and Ar ion-beam irradiated hydrated DNA samples. Taking dimethyl phosphate as a model of sugar-phosphate backbone, ESR and theoretical (DFT) studies of γ-irradiated dimethyl phosphate were carried out. CH3OP(O2−)OCH2• is formed via deprotonation from the methyl group of directly ionized dimethyl phosphate at 77 K. Formation of CH3OP(O2−)OCH2• is independent of dimethyl phosphate concentration (neat or in aqueous solution) or pH. ESR spectra of C5′• found in DNA and of CH3OP(O2−)OCH2• do not show an observable β-phosphorous hyperfine coupling (HFC). Further, C5′• found in DNA does not show a significant C4′-H β–proton HFC. Applying the DFT/B3LYP/6-31G(d) method, a study of conformational dependence of the phosphorous HFC in CH3OP(O2−)OCH2• shows that in its minimum energy conformation, CH3OP(O2−)OCH2• has a negligible β-phosphorous HFC. Based on these results, formation of radiation-induced C5′• is proposed to occur via a very rapid deprotonation from the directly ionized sugar-phosphate backbone and rate of this deprotonation must be faster than that of energetically downhill transfer of the unpaired spin (hole) from ionized sugar-phosphate backbone to the DNA bases. Moreover, C5′• in irradiated DNA is found to be in a conformation that does not exhibit β proton or β phosphorous HFCs. PMID:22553971

  9. Comparison of success rate of intubation through Air-Q with ILMA using two different endotracheal tubes

    PubMed Central

    Malhotra, SK; Bharath, KV; Saini, Vikas

    2016-01-01

    Background and Aims: Air-Q™ is a newly introduced airway device, which can be used to facilitate endotracheal intubation. The primary aim of this study was to assess whether use of two different endotracheal tubes (ETTs) (standard polyvinyl chloride [PVC] and reinforced PVC) increases the success rate of blind intubation through Air-Q™ (Group Q) when compared with intubating laryngeal mask airway (ILMA- Fastrach™) keeping ILMA as control (Group I). Methods: One hundred and twenty patients aged between 18 and 60 years with American Society of Anesthesiologists physical status I-II, undergoing elective surgery under general anaesthesia, were enrolled into this prospective, randomised, case–control study to compare the success rate of tracheal intubation between ILMA (Fastrach™) and Air-Q™ intubating laryngeal airway. Those patients with anticipated difficult airway were excluded from the study. All the recruited patients completed the study. Reinforced PVC ETT was used in both airway devices to secure intubation. Since standard PVC tube is recommended for use in Air-Q, when first intubation attempt failed, second or third attempt was made with standard PVC ETT. Total of three attempts were made for each procedure: Whereas in ILMA group, only reinforced tube was used in all three attempts. Results: The overall success rate after three attempts was more with Air-Q (96.6%) in our study compared with ILMA (91.6%) but no significant difference was seen between the groups (P = 0.43). Conclusion: The present study shows that when intubation with reinforced tube fails, the success rate with use of conventional PVC tube is more with Air-Q when compared with ILMA. PMID:27141106

  10. Do physical examination and CT-scan measures of femoral neck anteversion and tibial torsion relate to each other?

    PubMed

    Sangeux, Morgan; Mahy, Jessica; Graham, H Kerr

    2014-01-01

    Informed clinical decision making for femoral and/or tibial de-rotation osteotomies requires accurate measurement of patient function through gait analysis and anatomy through physical examination of bony torsions. Validity of gait analysis has been extensively studied; however, controversy remains regarding the accuracy of physical examination measurements of femoral and tibial torsion. Comparison between CT-scans and physical examination measurements of femoral neck anteversion (FNA) and external tibial torsion (ETT) were retrospectively obtained for 98 (FNA) and 64 (ETT) patients who attended a tertiary hospital for instrumented gait analysis between 2007 and 2010. The physical examination methods studied for femoral neck anteversion were the trochanteric prominence angle test (TPAT) and the maximum hip rotation arc midpoint (Arc midpoint) and for external tibial torsion the transmalleolar axis (TMA). Results showed that all physical examination measurements statistically differed to the CT-scans (bias(standard deviation): -2(14) for TPAT, -10(12) for Arc midpoint and -16(9) for TMA). Bland and Altman plots showed that method disagreements increased with increasing bony torsions in all cases but notably for TPAT. Regression analysis showed that only TMA and CT-scan measurement of external tibial torsion demonstrated good (R(2)=57%) correlation. Correlations for both TPAT (R(2)=14%) and Arc midpoint (R(2)=39%) with CT-scan measurements of FNA were limited. We conclude that physical examination should be considered as screening techniques rather than definitive measurement methods for FNA and ETT. Further research is required to develop more accurate measurement methods to accompany instrumented gait analysis.

  11. A model for an early role of auxin in Arabidopsis gynoecium morphogenesis

    PubMed Central

    Hawkins, Charles; Liu, Zhongchi

    2014-01-01

    The female reproductive organ of angiosperms, the gynoecium, often consists of the fusion of multiple ovule-bearing carpels. It serves the important function of producing and protecting ovules as well as mediating pollination. The gynoecium has likely contributed to the tremendous success of angiosperms over their 160 million year history. In addition, being a highly complex plant organ, the gynoecium is well suited to serving as a model system for use in the investigation of plant morphogenesis and development. The longstanding model of gynoecium morphogenesis in Arabidopsis holds that apically localized auxin biosynthesis in the gynoecium results in an apical to basal gradient of auxin that serves to specify along its length the development of style, ovary, and gynophore in a concentration-dependent manner. This model is based primarily on the observed effects of the auxin transport blocker N-1-naphthylphthalamic acid (NPA) as well as analyses of mutants of Auxin Response Factor (ARF) 3/ETTIN (ETT). Both NPA treatment and ett mutation disrupt gynoecium morphological patterns along the apical–basal axis. More than a decade after the model’s initial proposal, however, the auxin gradient on which the model critically depends remains elusive. Furthermore, multiple observations are inconsistent with such an auxin-gradient model. Chiefly, the timing of gynoecium emergence and patterning occurs at a very early stage when the organ has little-to-no apical–basal dimension. Based on these observations and current models of early leaf patterning, we propose an alternate model for gynoecial patterning. Under this model, the action of auxin is necessary for the early establishment of adaxial–abaxial patterning of the carpel primordium. In this case, the observed gynoecial phenotypes caused by NPA and ett are due to the disruption of this early adaxial–abaxial patterning of the carpel primordia. Here we present the case for this model based on recent literature and

  12. Independent Review of Elemental Phosphorus Remediation at the Eastern Michaud Flats FMC Operable Unit near Pocatello, Idaho

    SciTech Connect

    Martino, L. E.; Jerden, J. J.; Kimmell, T. A.; Quinn, J.

    2016-01-01

    If, despite risks to workers and these potential impacts, stakeholders decide that P4 wastes need to be excavated and treated, the Review Team determined that a number of the ETTs examined warrant further consideration for the treatment of P4 waste that has been characterized (for example, P4 waste present in the historical ponds). Nevertheless, concerns about the health and safety of site investigation workers using then-available investigation approaches prevented the collection of subsurface samples containing P4 from large areas of the site (e.g., the railroad swale, the vadose zone beneath the Furnace Building, and the abandoned railcars), As a result, the contaminant CSM in those particular areas was not refined enough to allow the Review Team to draw conclusions about using some of the ETTs to treat P4 waste in those areas. The readiness of an ETT for implementation varies depending on many factors, including stakeholder input, permitting, and remedial action construction requirements. Technologies that could be ready for use in the near term (within 1 year) include the following: mechanical excavation, containment technologies, off-site incineration, and drying and mechanical mixing under a tent structure. Technologies that could be ready for use in the mid-term (1 to 2 years) include cutter suction dredging, thermal-hydraulic dredging, and underground pipeline cleaning technologies. Technologies requiring a longer lead time (2 to 5 years) include on-site incineration, a land disposal restriction waste treatment system, an Albright & Wilson batch mud still, post-treatment on-site disposal, and post-treatment off-site disposal.

  13. Autoinducer-2 of Streptococcus mitis as a Target Molecule to Inhibit Pathogenic Multi-Species Biofilm Formation In Vitro and in an Endotracheal Intubation Rat Model

    PubMed Central

    Wang, Zhengli; Xiang, Qingqing; Yang, Ting; Li, Luquan; Yang, Jingli; Li, Hongong; He, Yu; Zhang, Yunhui; Lu, Qi; Yu, Jialin

    2016-01-01

    Streptococcus mitis (S. mitis) and Pseudomonas aeruginosa (P. aeruginosa) are typically found in the upper respiratory tract of infants. We previously found that P. aeruginosa and S. mitis were two of the most common bacteria in biofilms on newborns’ endotracheal tubes (ETTs) and in their sputa and that S. mitis was able to produce autoinducer-2 (AI-2), whereas P. aeruginosa was not. Recently, we also found that exogenous AI-2 and S. mitis could influence the behaviors of P. aeruginosa. We hypothesized that S. mitis contributes to this interspecies interaction and that inhibition of AI-2 could result in inhibition of these effects. To test this hypothesis, we selected PAO1 as a representative model strain of P. aeruginosa and evaluated the effect of S. mitis as well as an AI-2 analog (D-ribose) on mono- and co-culture biofilms in both in vitro and in vivo models. In this context, S. mitis promoted PAO1 biofilm formation and pathogenicity. Dual-species (PAO1 and S. mitis) biofilms exhibited higher expression of quorum sensing genes than single-species (PAO1) biofilms did. Additionally, ETTs covered in dual-species biofilms increased the mortality rate and aggravated lung infection compared with ETTs covered in mono-species biofilms in an endotracheal intubation rat model, all of which was inhibited by D-ribose. Our results demonstrated that S. mitis AI-2 plays an important role in interspecies interactions with PAO1 and may be a target for inhibition of biofilm formation and infection in ventilator-associated pneumonia. PMID:26903968

  14. Effect of noble metal alloy post and core material on the fracture resistance of endodontically treated teeth.

    PubMed

    Toksavul, Suna; Toman, Muhittin; Sarikanat, Mehmet; Nergiz, Ibrahim; Schmage, Petra

    2010-03-01

    The aim of this study was to investigate the effect of one particular brand of post and core system (ER Post) consisted of different post and core materials on the fracture resistance of endodontically treated teeth. Fifty caries-free maxillary central incisors were randomly assigned to five groups (n=10). All teeth were sectioned at the cemento-enamel junction except for the teeth in the control group. Four experimental groups consisted of cast gold post-and-core group (GG), Heraplat post/cast gold core group (HG), titanium post/composite core (TC), and titanium post/cast gold core (TG). The control group (ETT) consisted of endodontically treated teeth without posts. All posts were cemented in the roots with zinc phosphate cement. Following thermal cycling (5000 cycles between 5 degrees C and 55 degrees C with a dwell time of 30 seconds) a static load was applied to 2 mm below the incisal edge on the palatal surface of each specimen until they were fractured. Fracture data obtained and statistically analyzed with one-way ANOVA and a Tukey's test (p<0.05). Means of the fracture resistance during static loading were: 423.76 N (GG), 529.46 N (HG), 389.08 N (TC), 408.7 N (TG), 404.4 N (ETT, control). Heraplat post with cast gold core exhibited the highest fracture load than the other groups (p<0.05). Specimens in groups HG and ETT (control) showed the most repairable failure. Heraplat post with cast gold core had the highest fracture resistance of endodontically treated teeth.

  15. Retrograde and submental intubation.

    PubMed

    Ramsey, Cyrus A; Dhaliwal, Sukhdeep S

    2010-03-01

    Direct laryngoscopy remains the technique of choice for placing an endotracheal tube (ETT). However, alternative techniques are needed for the difficult airway or unsuccessful intubation. Retrograde intubation may be used in adult or pediatric patients, whether awake, sedated, or obtunded. Contraindications include nonpalpable neck landmarks, pretracheal mass, severe flexion deformities of the neck, tracheal stenosis, coagulopathies, and infections. Submental intubation allows simultaneous access to the dental occlusion and nasal pyramid without the morbidity associated with tracheostomy. Contraindications include patients who require long periods of assisted ventilation and a severe traumatic wound on the floor of mouth. Complications include localized infection and sepsis, poor wound healing or scarring, and postoperative salivary fistula.

  16. High temperature shock tube and theoretical studies on the thermal decomposition of dimethyl carbonate and its bimolecular reactions with H and D-atoms.

    PubMed

    Peukert, S L; Sivaramakrishnan, R; Michael, J V

    2013-05-01

    The shock tube technique was used to study the high temperature thermal decomposition of dimethyl carbonate, CH3OC(O)OCH3 (DMC). The formation of H-atoms was measured behind reflected shock waves by using atomic resonance absorption spectrometry (ARAS). The experiments span a T-range of 1053-1157 K at pressures ∼0.5 atm. The H-atom profiles were simulated using a detailed chemical kinetic mechanism for DMC thermal decomposition. Simulations indicate that the formation of H-atoms is sensitive to the rate constants for the energetically lowest-lying bond fission channel, CH3OC(O)OCH3 → CH3 + CH3OC(O)O [A], where H-atoms form instantaneously at high temperatures from the sequence of radical β-scissions, CH3OC(O)O → CH3O + CO2 → H + CH2O + CO2. A master equation analysis was performed using CCSD(T)/cc-pv∞z//M06-2X/cc-pvtz energetics and molecular properties for all thermal decomposition processes in DMC. The theoretical predictions were found to be in good agreement with the present experimentally derived rate constants for the bond fission channel (A). The theoretically derived rate constants for this important bond-fission process in DMC can be represented by a modified Arrhenius expression at 0.5 atm over the T-range 1000-2000 K as, kA(T) = 6.85 × 10(98)T (-24.239) exp(-65250 K/T) s(-1). The H-atom temporal profiles at long times show only minor sensitivity to the abstraction reaction, H + CH3OC(O)OCH3 → H2 + CH3OC(O)OCH2 [B]. However, H + DMC is an important fuel destruction reaction at high temperatures. Consequently, measurements of D-atom profiles using D-ARAS allowed unambiguous rate constant measurements for the deuterated analog of reaction B, D + CH3OC(O)OCH3 → HD + CH3OC(O)OCH2 [C]. Reaction C is a surrogate for H + DMC since the theoretically predicted kinetic isotope effect at high temperatures (1000 - 2000K) is close to unity, kC ≈ 1.2 kB. TST calculations employing CCSD(T)/cc-pv∞z//M06-2X/cc-pvtz energetics and molecular properties

  17. On the structural and electronic considerations concerning the reactivity of metal-metal multiple bonds

    NASA Astrophysics Data System (ADS)

    Glasgow, Katherine Campbell

    2000-10-01

    The previously known compound W2(OCH2tBu) 6(py)2 is crystallographically characterized. Its solid state structure is described and compared with other M2(OR)6L 2 complexes. Upon treatment with isoprene, the complex W2(OCH 2tBu)6(py)(mu-isoprene) forms. The solid state structure is disordered with respect to the orientation of the diene; two different configurations are seen in the crystal structure. These two isomers are in equilibrium in solution and are visible by 1H NMR spectroscopy. Multidimensional NMR experiments are used to assign the structures of the two isomers in solution. Through the use of spin magnetization transfer, it has been determined that the two isomers interconvert through the loss of isoprene. The DeltaH° and DeltaS° values for the equilibrium are determined. The starting material W2(OCH2tBu) 6(py)2 had been previously determined to be an olefin hydrogenation catalyst. It has been determined that cyclic olefins are hydrogenated in a cis manner, and a kinetic isotope effect of 1.7 has been measured. It has been determined that olefins which form isolable adducts with W 2(OCH2tBu)6(py)2, such as isoprene, undergo hydrogenation at approximately the same rate as olefins which do not show evidence of adduct formation. The complex W2(OCH2tBu)6(py) 2had been found to couple aldehydes and ketones stoichiometrically to give olefins. The reaction was found to proceed in a stepwise manner through the alkylidene intermediate W2(OCH2tBu) 6(py)(O)(mu-CHR), allowing the selective cross coupling of aldehydes and ketones. More studies have been undertaken to help determine the scope of the reaction. Competition experiments have been performed to determine reaction preferences. Unsaturated and functionalized aldehydes have been studied to determine the tolerance of the reaction to certain chemical groups. The role of pyridine in this reaction has been studied, especially concerning its reactivity with the alkylidene intermediate. The dimetal tetracarboxylate

  18. Changes in vacuolation in the root apex cells of soybean seedlings in microgravity

    NASA Astrophysics Data System (ADS)

    Klymchuk, D. O.; Kordyum, E. L.; Vorobyova, T. V.; Chapman, D. K.; Brown, C. S.

    2003-05-01

    Changes in the vacuolation in root apex cells of soybean ( Glycine max L. [Merr.]) seedlings grown in microgravity were investigated. Spaceflight and ground control seedlings were grown in the absence or presence of KMnO 4 (to remove ethylene) for 6 days. After landing, in order to study of cell ultrastructure and subcellular free calcium ion distribution, seedling root apices were fixed in 2.5% (w/v) glutaraldehyde in 0.1 M cacodylate buffer and 2% (w/v) glutaraldehyde, 2.5% (w/v) formaldehyde, 2% (w/v) potassium antimonate K[Sb(OH) 6] in 0.1 M K 2HPO 4 buffer with an osmolarity (calculated theoretically) of 0.45 and 1.26 osmol. The concentrations of ethylene in all spaceflight canisters were significantly higher than in the ground control canisters. Seedling growth was reduced in the spaceflight-exposed plants. Additionally, the spaceflight-exposed plants exhibited progressive vacuolation in the root apex cells, particularly in the columella cells, to a greater degree than the ground controls. Plasmolysis was observed in columella cells of spaceflight roots fixed in solutions with relatively high osmolarity (1.26 osmol). The appearance of plasmolysis permitted the evaluation of the water status of cells. The water potential of the spaceflight cells was higher than the surrounding fixative solution. A decrease in osmotic potential and/or an increase in turgor potential may have induced increases in cell water potential. However, the plasmolysed (i.e. nonturgid) cells implied that increases in water potential were accompanied with a decrease in osmotic potential. In such cells changes in vacuolation may have been involved to maintain turgor pressure or may have been a result of intensification of other vacuolar functions like digestion and storage

  19. Changes in vacuolation in the root apex cells of soybean seedlings in microgravity

    NASA Astrophysics Data System (ADS)

    Klymchuk, D.; Kordyum, E.; Chapman, D.; Brown, C.; Vorobyova, T.

    In this study, changes in the vacuolation in root apex cells of soybean (Glycine max L. [Merr.]) seedlings grown in microgravity were investigated. Dry seeds were mounted within BRIC (Biological Research in Canister) before launching, activated and germinated on board the space shuttle Columbia (STS 87). Spaceflight and- ground control seedlings were grown in the presence of KMnO4 (to remove ethylene) and in the absence of KMnO4 for 6 days. After landing, seedling root apices were fixed in a solutions (2.5% (w/v) glutaraldehyde in 0.1 M cacodilate buffer and 2% (w/v) glutaraldehyde, 2.5% (w/v) formaldehyde, 2% (w/v) potassium antimonate K[Sb(OH)6] in 0.1 M K2HPO4 buffer) with osmolarity (accounted theoretically) 0.45 and 1.26 osmol for study of cell ultrastructure and subcellular free calcium ion distribution correspondingly. The concentration of ethylene in all spaceflight canisters were significantly higher than in the ground controls. Seedling growth and lateral root formation decreased in microgravity and the progressive vacuolation in root apex cells, particularly in collumela cells, was observed unlike the ground controls. In addition, plasmolysis in collumela cells of spaceflight roots treated by solution with relatively high osmolarity occurred. The appearance of plasmolysis permitted the evaluation of the water status of cells. The water potential of the spaceflight cells is higher than the surrounding fxative solution (1.26 osmol). Ai decrease in osmotic potential and/or an increase in turgor potential may bring about increases in cell water potential. However, the plasmolysed (i.e. nonturgid) cells imply that increases in water potential accompanied with a decrease in osmotic potential. In such cells, changes in vacuolation, which may be involved to maintain turgor pressure or may be a result of intensification of other vacuole functions as digestion, storage are discussed.

  20. Three-Dimensional Reduced Graphene Oxide Coupled with Mn3O4 for Highly Efficient Removal of Sb(III) and Sb(V) from Water.

    PubMed

    Zou, Jian-Ping; Liu, Hui-Long; Luo, Jinming; Xing, Qiu-Ju; Du, Hong-Mei; Jiang, Xun-Heng; Luo, Xu-Biao; Luo, Sheng-Lian; Suib, Steven L

    2016-07-20

    Highly porous, three-dimensional (3D) nanostructured composite adsorbents of reduced graphene oxides/Mn3O4 (RGO/Mn3O4) were fabricated by a facile method of a combination of reflux condensation and solvothermal reactions and systemically characterized. The as-prepared RGO/Mn3O4 possesses a mesoporous 3D structure, in which Mn3O4 nanoparticles are uniformly deposited on the surface of the reduced graphene oxide. The adsorption properties of RGO/Mn3O4 to antimonite (Sb(III)) and antimonate (Sb(V)) were investigated using batch experiments of adsorption isotherms and kinetics. Experimental results show that the RGO/Mn3O4 composite has fast liquid transport and superior adsorption capacity toward antimony (Sb) species in comparison to six recent adsorbents reported in the literature and summarized in a table in this paper. Theoretical maximum adsorption capacities of RGO/Mn3O4 toward Sb(III) and Sb(V) are 151.84 and 105.50 mg/g, respectively, modeled by Langmuir isotherms. The application of RGO/Mn3O4 was demonstrated by using drinking water spiked with Sb (320 μg/L). Fixed-bed column adsorption experiments indicate that the effective breakthrough volumes were 859 and 633 mL bed volumes (BVs) for the Sb(III) and Sb(V), respectively, until the maximum contaminant level of 5 ppb was reached, which is below the maximum limits allowed in drinking water according to the most stringent regulations. The advantages of being nontoxic, highly stable, and resistant to acid and alkali and having high adsorption capacity toward Sb(III) and Sb(V) confirm the great potential application of RGO/Mn3O4 in Sb-spiked water treatment. PMID:27355752

  1. Anion-Controlled Positional Switching of a Phenyl Group about the Dinuclear Core of a AuSb Complex.

    PubMed

    Sen, Srobona; Ke, Iou-Sheng; Gabbaï, François P

    2016-09-19

    As part of our continuing interest in redox-active, anion-responsive main-group transition-metal platforms, we have investigated the effect of chloride by fluoride anion substitution on the core structure of a dinuclear AuSb platform. Starting from [(o-(iPr2P)C6H4)2Cl2SbPh]AuCl (2) in which the antimony-bound phenyl group is positioned trans to the gold atom, we found that the introduction of fluoride anions, as in [(o-(iPr2P)C6H4)2F2SbPh]AuCl (3) and [(o-(iPr2P)C6H4)2ClFSbPh]AuCl (4), produces structures in which the phenyl group switches to a perpendicular direction with respect to the gold atom. Replacement of the gold-bound chloride anion in 3 by a fluoride anion can be achieved by successive treatment with TlPF6 and [nBu4N][Ph3SiF2]. These reactions, which proceed via the intermediate zwitterionc gold antimonate complex [o-(iPr2P)C6H4)2F3SbPh]Au (6), trigger migration of the phenyl group to gold and afford [(o-(iPr2P)C6H4)2F3Sb]AuPh (7). Because the phenyl group in 7 is orthogonal to that in 3 and opposite to that in 2, the title AuSb platform can be regarded as a molecular analogue of a mechanical three-way switch in which the switching element is a phenyl group. Finally, while all complexes involved retain a Au → Sb interaction, this interaction is no longer present in the zwitterionic derivative 6 because of the neutralization of the Lewis acidity of the antimony center. PMID:27583565

  2. Changes in vacuolation in the root apex cells of soybean seedlings in microgravity

    NASA Technical Reports Server (NTRS)

    Klymchuk, D. O.; Kordyum, E. L.; Vorobyova, T. V.; Chapman, D. K.; Brown, C. S.

    2003-01-01

    Changes in the vacuolation in root apex cells of soybean (Glycine max L. [Merr.]) seedlings grown in microgravity were investigated. Spaceflight and ground control seedlings were grown in the absence or presence of KMnO4 (to remove ethylene) for 6 days. After landing, in order to study of cell ultrastructure and subcellular free calcium ion distribution, seedling root apices were fixed in 2.5% (w/v) glutaraldehyde in 0.1 M cacodylate buffer and 2% (w/v) glutaraldehyde, 2.5% (w/v) formaldehyde, 2% (w/v) potassium antimonate K[Sb(OH)6] in 0.1 M K2HPO4 buffer with an osmolarity (calculated theoretically) of 0.45 and 1.26 osmol. The concentrations of ethylene in all spaceflight canisters were significantly higher than in the ground control canisters. Seedling growth was reduced in the spaceflight-exposed plants. Additionally, the spaceflight-exposed plants exhibited progressive vacuolation in the root apex cells, particularly in the columella cells, to a greater degree than the ground controls. Plasmolysis was observed in columella cells of spaceflight roots fixed in solutions with relatively high osmolarity (1.26 osmol). The appearance of plasmolysis permitted the evaluation of the water status of cells. The water potential of the spaceflight cells was higher than the surrounding fixative solution. A decrease in osmotic potential and/or an increase in turgor potential may have induced increases in cell water potential. However, the plasmolysed (i.e. non-turgid) cells implied that increases in water potential were accompanied with a decrease in osmotic potential. In such cells changes in vacuolation may have been involved to maintain turgor pressure or may have been a result of intensification of other vacuolar functions like digestion and storage. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

  3. Antimony uptake, efflux and speciation in arsenic hyperaccumulator Pteris vittata.

    PubMed

    Tisarum, Rujira; Lessl, Jason T; Dong, Xiaoling; de Oliveira, Letuzia M; Rathinasabapathi, Bala; Ma, Lena Q

    2014-03-01

    Even though antimony (Sb) and arsenic (As) are chemical analogs, differences exist on how they are taken up and translocated in plants. We investigated 1) Sb uptake, efflux and speciation in arsenic hyperaccumulator Pteris vittata after 1 d exposure to 1.6 or 8 mg/L antimonite (SbIII) or antimonate (SbV), 2) Sb uptake by PV accessions from Florida, China, and Brazil after 7 d exposure to 8 mg/L SbIII, and 3) Sb uptake and oxidation by excised PV fronds after 1 d exposure to 8 mg/L SbIII or SbV. After 1 d exposure, P. vittata took 23-32 times more SbIII than SbV, with all Sb being accumulated in the roots with the highest at 4,192 mg/kg. When exposed to 8 mg/L SbV, 98% of Sb existed as SbV in the roots. In comparison, when exposed to 8 mg/L SbIII, 81% of the total Sb remained as SbIII and 26% of the total Sb was effluxed out into the media. The three PV accessions had a similar ability to accumulate Sb at 12,000 mg/kg in the roots, with >99% of total Sb in the roots. Excised PV fronds translocated SbV more efficiently from the petioles to pinnae than SbIII and were unable to oxidize SbIII. Overall, P. vittata displayed efficient root uptake and efflux of SbIII with limited ability to translocate and transform in the roots.

  4. Global Regulator IscR Positively Contributes to Antimonite Resistance and Oxidation in Comamonas testosteroni S44

    PubMed Central

    Liu, Hongliang; Zhuang, Weiping; Zhang, Shengzhe; Rensing, Christopher; Huang, Jun; Li, Jie; Wang, Gejiao

    2015-01-01

    Antimonial compounds can be found as a toxic contaminant in the environment. Knowledge on mechanisms of microbial Sb oxidation and its role in microbial tolerance are limited. Previously, we found that Comamonas testosteroni S44 was resistant to multiple heavy metals and was able to oxidize the toxic antimonite [Sb(III)] to the much less toxic antimonate [Sb(V)]. In this study, transposon mutagenesis was performed in C. testosteroni S44 to isolate genes responsible for Sb(III) resistance and oxidation. An insertion mutation into iscR, which regulates genes involved in the biosynthesis of Fe-S clusters, generated a strain called iscR-280. This mutant strain was complemented with a plasmid carrying iscR to generate strain iscR-280C. Compared to the wild type S44 and iscR-280C, strain iscR-280 showed lower resistance to Sb(III) and a lower Sb(III) oxidation rate. Strain iscR-280 also showed lower resistance to As(III), Cd(II), Cu(II), and H2O2. In addition, intracellular γ-glutamylcysteine ligase (γ-GCL) activity and glutathione (GSH) content were decreased in the mutated strain iscR-280. Real-time RT-PCR and lacZ fusion expression assay indicated that transcription of iscR and iscS was induced by Sb(III). Results of electrophoretic mobility shift assay (EMSA) and bacterial one-hybrid (B1H) system demonstrated a positive interaction between IscR and its promoter region. The diverse defective phenotypes and various expression patterns suggest a role for IscR in contributing to multi-metal(loid)s resistance and Sb(III) oxidation via Fe-S cluster biogenesis and oxidative stress protection. Bacterial Sb(III) oxidation is a detoxification reaction. PMID:26734615

  5. Residence of silver in mineral deposits of the Thunder Mountain caldera complex, Central Idaho, U.S.A.

    USGS Publications Warehouse

    Leonard, B.F.; Christian, R.P.

    1987-01-01

    Silver is an accessory element in gold, antimony, and tungsten deposits of the caldera complex. Most of the deposits are economically of low grade and genetically of xenothermal or epithermal character. Their gold- and silver-bearing minerals are usually disseminated, fine grained, and difficult to study. Sparsely disseminated pyrite and arsenoprite are common associates. Identified silver minerals are: native silver and electrum; the sulfides acanthite, argentite (the latter always inverted to acanthite), and members of the Silberkies group; the sulfosalts matildite, miargyrite, pyrargyrite, argentian tetrahedrite, and unnamed Ag-Sb-S and Ag-Fe-Sb-S minerals; the telluride hessite and the selenide naumannite; halides of the cerargyrite group; and the antimonate stetefeldtite. Suspected silver minerals include the sulfide uytenbogaardtite and the sulfosalts andorite, diaphorite, and polybasite. Electrum, acanthite, and argentian tetrahedrite are common, though nowhere abundant. The other silver minerals are rare. Silver is present as a minor element in the structure of some varieties of other minerals. These include arsenopyrite, chalcopyrite, chalcostibite, covelline, digenite, galena, sphalerite, and stibnite. The search for adventitious Ag in most of these minerals has been cursory. The results merely indicate that elemental silver is not confined to discrete silver minerals and is, therefore, an additional complication for the recovery of silver-bearing material from some deposits. Silver occurs cryptically in some plants of the region. At Red Mountain, for example, the ashed sapwood of Douglas-fir (Pseudotsuga menziesii) contains 2 to 300 ppm Ag. Silver in the ashed wood is roughly 100 times as abundant as it is in soil. The phenomenon, useful in biogeochemical exploration, deserves the attention of mineralogists. ?? 1987 Springer-Verlag.

  6. In vivo/In vitro immune responses to L. major isolates from patients with no clinical response to Glucantime

    PubMed Central

    Saberi, Sedigheh; Arjmand, Reza; Soleimanifard, Simindokht; Khamesipour, Ali; Hosseini, Seyed Mohsen; Salehi, Mansoor; Varshosaz, Jaleh; Palizban, Abbas Ali; Hejazi, Seyed Hossein

    2016-01-01

    Background: Leishmaniasis is a major health problem in some endemic areas of tropical and subtropical areas of the world. Interleukin-12 (IL-12) and interferon gamma (IFN-γ) are essential cytokines associated with initiation of Th1 response. The main objective of this study was to evaluate of the type of immune response to L. major isolates from patients with no clinical response to antimonite (Glucantime). Materials and Methods: This experimental study was carried out during 2013–2014. In the current study Leishmania major were isolated from 10 CL patients with a history of at least one course of treatment with Meglumine antimonate (Sb5). The isolates were used to evaluate in vitro and in vivo response to Sb5. J774 murine macrophage cell line was used for in vitro tests and Balb/c mice was used for in vivo studies. IL-12 gene expression was evaluated using Real-time PCR and IFN-γ serum level was quantified using ELISA technique. SPSS (version: 20), analysis of Covariance (ANCOVA) was used for statistical analysis. Results: PCR results confirmed that all 10 isolates were L. major. The mean of IL-12 gene expression in vitro, in vivo and IFN-γ serum levels (pg/ml) after 2 and 3 weeks treatment in vivo, increased significantly following the treatment with Glucantime in the two groups of Balb/c mice infected either with patients' isolates or standard L. major. No significant difference was seen between the patients' isolates and standard species. Conclusions: Although the L. major were isolated from patients with active lesion and no clinical response to Glucantime after at least one courses of Glucantime treatment but in vivo and in vitro immune response of L. major isolates showed no difference between the patients' isolates and standard L. major. PMID:27563636

  7. Simultaneous removal of Cd(II) and Sb(V) by Fe-Mn binary oxide: Positive effects of Cd(II) on Sb(V) adsorption.

    PubMed

    Liu, Ruiping; Liu, Feng; Hu, Chengzhi; He, Zan; Liu, Huijuan; Qu, Jiuhui

    2015-12-30

    The coexistence of cadmium ion (Cd(II)) and antimonate (Sb(V)) creates the need for their simultaneous removal. This study aims to investigate the effects of positively-charged Cd(II) on the removal of negative Sb(V) ions by Fe-Mn binary oxide (FMBO) and associated mechanisms. The maximum Sb(V) adsorption density (Qmax,Sb(V)) increased from 1.02 to 1.32 and 2.01 mmol/g in the presence of Cd(II) at 0.25 and 0.50 mmol/L. Cd(2+) exhibited a more significant positive effect than both calcium ion (Ca(2+)) and manganese ion (Mn(2+)). Cd(2+) showed higher affinity towards FMBO and increased its ζ-potential more significantly compared to Ca(2+) and Mn(2+). The simultaneous adsorption of Sb(V) and Cd(II) onto FMBO can be achieved over a wide initial pH (pHi) range from 2 to 9, and QSb(V) decreases whereas QCd(II) increases with elevated pHi. Their combined values, as expressed by QSb(V)+Cd(II), amount to about 2 mmol/g and vary slightly in the pHi range 4-9. FTIR and XPS spectra indicate the significant synergistic effect of Cd(II) on Sb(V) adsorption onto FMBO, and that little chemical valence transformation occurs. These results may be valuable for the treatment of wastewater with coexisting heavy metals such as Cd(II) and Sb(V). PMID:26340552

  8. High antiferromagnetic transition temperature of a honeycomb compound SrRu2O6

    SciTech Connect

    Tian, Wei; Svoboda, Chris; Ochi, M.; Matsuda, M.; Cao, Huibo; Cheng, J. -G.; Sales, B. C.; Mandrus, D.; Arita, R.; Trivedi, Nandini; Yan, Jiaqiang

    2015-09-14

    We study the high-temperature magnetic order in a quasi-two-dimensional honeycomb compound SrRu2O6 by measuring magnetization and neutron powder diffraction with both polarized and unpolarized neutrons. SrRu2O6 crystallizes into the hexagonal lead antimonate (PbSb2O6, space group P31m) structure with layers of edge-sharing RuO6 octahedra separated by Sr2+ ions. SrRu2O6 is found to order at TN = 565 K with Ru moments coupled antiferromagnetically both in plane and out of plane. The magnetic moment is 1.30(2) μB/Ru at room temperature and is along the crystallographic c axis in the G-type magnetic structure. We perform density functional calculations with constrained random-phase approximation (RPA) to obtain the electronic structure and effective intra- and interorbital interaction parameters. The projected density of states shows strong hybridization between Ru 4d and O 2p. By downfolding to the target t2g bands we extract the effective magnetic Hamiltonian and perform Monte Carlo simulations to determine the transition temperature as a function of interand intraplane couplings. We find a weak interplane coupling, 3% of the strong intraplane coupling, permits three-dimensional magnetic order at the observed TN .

  9. Localization of calcium in the pericarp cells of tomato fruits during the development of blossom-end rot.

    PubMed

    Suzuki, K; Shono, M; Egawa, Y

    2003-01-01

    Blossom-end rot (BER) of tomato ( Lycopersicon esculentum) fruits is considered to be a physiological disorder caused by calcium deficiency. We attempted to clarify the localization of calcium in the pericarp cells and the ultrastructural changes during the development of BER. Calcium precipitates were observed as electron-dense deposits by an antimonate precipitation method. Some calcium precipitates were localized in the cytosol, nucleus, plastids, and vacuoles at an early developmental stage of normal fruits. Calcium precipitates were increased markedly on the plasma membrane during the rapid-fruit-growth stage compared with their level at the early stage. Cell collapse occurred in the water-soaked region at the rapid-fruit-growth stage in BER fruits. There were no visible calcium precipitates on the traces of plasma membrane near the cell wall of the collapsed cells. The amount of calcium precipitates on plasma membranes near collapsed cells was smaller than that in the cells of normal fruits and normal parts of BER fruits, and the amount on cells near collapsed cells was small. The amount of calcium precipitates on the plasma membranes increased as the distance from collapsed cells increased. On the other hand, calcium precipitates were visible normally in the cytosol, organelles, and vacuoles and even traces of them in collapsed cells. The distribution pattern of the calcium precipitates on the plasma membrane was thus considerably different between normal and BER fruits. On the basis of these observations, we concluded that calcium deficiency in plasma membranes caused cell collapses in BER tomato fruits.

  10. Oxalic Acid Has an Additional, Detoxifying Function in Sclerotinia sclerotiorum Pathogenesis

    PubMed Central

    Heller, Annerose; Witt-Geiges, Tanja

    2013-01-01

    The mechanism of the diseases caused by the necrotroph plant pathogen Sclerotinia sclerotiorum is not well understood. To investigate the role of oxalic acid during infection high resolution, light-, scanning-, transmission electron microscopy and various histochemical staining methods were used. Our inoculation method allowed us to follow degradation of host plant tissue around single hyphae and to observe the reaction of host cells in direct contact with single invading hyphae. After penetration the outer epidermal cell wall matrix appeared degraded around subcuticular hyphae (12-24 hpi). Calcium oxalate crystals were detected in advanced (36-48 hpi) and late (72 hpi) infection stages, but not in early stages. In early infection stages, surprisingly, no toxic effect of oxalic acid eventually secreted by S. sclerotiorum was observed. As oxalic acid is a common metabolite in plants, we propose that attacked host cells are able to metabolize oxalic acid in the early infection stage and translocate it to their vacuoles where it is stored as calcium oxalate. The effects, observed on healthy tissue upon external application of oxalic acid to non-infected, living tissue and cell wall degradation of dead host cells starting at the inner side of the walls support this idea. The results indicate that oxalic acid concentrations in the early stage of infection stay below the toxic level. In plant and fungi oxalic acid/calcium oxalate plays an important role in calcium regulation. Oxalic acid likely could quench calcium ions released during cell wall breakdown to protect growing hyphae from toxic calcium concentrations in the infection area. As calcium antimonate-precipitates were found in vesicles of young hyphae, we propose that calcium is translocated to the older parts of hyphae and detoxified by building non-toxic, stable oxalate crystals. We propose an infection model where oxalic acid plays a detoxifying role in late infection stages. PMID:23951305

  11. Fiberoptic intubation through laryngeal mask airway for management of difficult airway in a child with Klippel–Feil syndrome

    PubMed Central

    Bhat, Ravi; Mane, Rajesh S.; Patil, Manjunath C.; Suresh, S. N.

    2014-01-01

    The ideal airway management modality in pediatric patients with syndromes like Klippel-Feil syndrome is a great challenge and is technically difficult for an anesthesiologist. Half of the patients present with the classic triad of short neck, low hairline, and fusion of cervical vertebra. Numerous associated anomalies like scoliosis or kyphosis, cleft palate, respiratory problems, deafness, genitourinary abnormalities, Sprengel's deformity (wherein the scapulae ride high on the back), synkinesia, cervical ribs, and congenital heart diseases may further add to the difficulty. Fiberoptic bronchoscopy alone can be technically difficult and patient cooperation also becomes very important, which is difficult in pediatric patients. Fiberoptic bronchoscopy with the aid of supraglottic airway devices is a viable alternative in the management of difficult airway in children. We report a case of Klippel-Feil syndrome in an 18-month-old girl posted for cleft palate surgery. Imaging of spine revealed complete fusion of the cervical vertebrae with hypoplastic C3 and C6 vertebrae and thoracic kyphosis. We successfully managed airway in this patient by fiberoptic intubation through classic laryngeal mask airway (LMA). After intubation, we used second smaller endotracheal tube (ETT) to stabilize and elongate the first ETT while removing the LMA. PMID:25191201

  12. Fibre reinforcement in a structurally compromised endodontically treated molar: a case report

    PubMed Central

    de Ataide, Ida de Noronha; Fernandes, Marina; Lambor, Rajan

    2016-01-01

    The reconstruction of structurally compromised posterior teeth is a rather challenging procedure. The tendency of endodontically treated teeth (ETT) to fracture is considerably higher than vital teeth. Although posts and core build-ups followed by conventional crowns have been generally employed for the purpose of reconstruction, this procedure entails sacrificing a considerable amount of residual sound enamel and dentin. This has drawn the attention of researchers to fibre reinforcement. Fibre-reinforced composite (FRC), designed to replace dentin, enables the biomimetic restoration of teeth. Besides improving the strength of the restoration, the incorporation of glass fibres into composite resins leads to favorable fracture patterns because the fibre layer acts as a stress breaker and stops crack propagation. The following case report presents a technique for reinforcing a badly broken-down ETT with biomimetic materials and FRC. The proper utilization of FRC in structurally compromised teeth can be considered to be an economical and practical measure that may obviate the use of extensive prosthetic treatment. PMID:27200283

  13. Numerical investigation of pulmonary drug delivery under mechanical ventilation conditions

    NASA Astrophysics Data System (ADS)

    Banerjee, Arindam; van Rhein, Timothy

    2012-11-01

    The effects of mechanical ventilation waveform on fluid flow and particle deposition were studied in a computer model of the human airways. The frequency with which aerosolized drugs are delivered to mechanically ventilated patients demonstrates the importance of understanding the effects of ventilation parameters. This study focuses specifically on the effects of mechanical ventilation waveforms using a computer model of the airways of patient undergoing mechanical ventilation treatment from the endotracheal tube to generation G7. Waveforms were modeled as those commonly used by commercial mechanical ventilators. Turbulence was modeled with LES. User defined particle force models were used to model the drag force with the Cunningham correction factor, the Saffman lift force, and Brownian motion force. The endotracheal tube (ETT) was found to be an important geometric feature, causing a fluid jet towards the right main bronchus, increased turbulence, and a recirculation zone in the right main bronchus. In addition to the enhanced deposition seen at the carinas of the airway bifurcations, enhanced deposition was also seen in the right main bronchus due to impaction and turbulent dispersion resulting from the fluid structures created by the ETT. Authors acknowledge financial support through University of Missouri Research Board Award.

  14. Airway accidents in critical care unit: A 3-year retrospective study in a Public Teaching Hospital of Eastern India

    PubMed Central

    Dasgupta, Sugata; Singh, Shipti Shradha; Chaudhuri, Arunima; Bhattacharya, Dipasri; Choudhury, Sourav Das

    2016-01-01

    Background: Although tracheal tubes are essential devices to control and protect airway in a critical care unit (CCU), they are not free from complications. Aims: To document the incidence and nature of airway accidents in the CCU of a government teaching hospital in Eastern India. Methods: Retrospective analysis of all airway accidents in a 5-bedded (medical and surgical) CCU. The number, types, timing, and severity of airway accidents were analyzed. Results: The total accident rate was 19 in 233 intubated and/or tracheostomized patients over 1657 tube days (TDs) during 3 years. Fourteen occurred in 232 endotracheally intubated patients over 1075 endotracheal tube (ETT) days, and five occurred in 44 tracheostomized patients over 580 tracheostomy TDs. Fifteen accidents were due to blocked tubes. Rest four were unplanned extubations (UEs), all being accidental extubations. All blockages occurred during night shifts and all UEs during day shifts. Five accidents were mild, the rest moderate. No major accident led to cardiorespiratory arrest or death. All blockages occurred after 7th day of intubation. The outcome of accidents were more favorable in tracheostomy group compared to ETT group (P = 0.001). Conclusions: The prevalence of airway accidents was 8.2 accidents per 100 patients. Blockages were the most common accidents followed by UEs. Ten out of the 15 blockages and all 4 UEs were in endotracheally intubated patients. Tracheostomized patients had 5 blockages and no UEs. PMID:27076709

  15. Fluid flow and particle transport in mechanically ventilated airways. Part I. Fluid flow structures.

    PubMed

    Van Rhein, Timothy; Alzahrany, Mohammed; Banerjee, Arindam; Salzman, Gary

    2016-07-01

    A large eddy simulation-based computational study of fluid flow and particle transport in upper tracheobronchial airways is carried out to investigate the effect of ventilation parameters on pulmonary fluid flow. Respiratory waveforms commonly used by commercial mechanical ventilators are used to study the effect of ventilation parameters and ventilation circuit on pulmonary fluid dynamics. A companion paper (Alzahrany et al. in Med Biol Eng Comput, 2014) reports our findings on the effect of the ventilation parameters and circuit on particle transport and aerosolized drug delivery. The endotracheal tube (ETT) was found to be an important geometric feature and resulted in a fluid jet that caused an increase in turbulence and created a recirculation zone with high wall shear stress in the main bronchi. Stronger turbulence was found in lower airways than would be found under normal breathing conditions due to the presence of the jet caused by the ETT. The pressure-controlled sinusoidal waveform induced the lowest wall shear stress on the airways wall. PMID:26563199

  16. Who gets admitted to the Chest Pain Unit (CPU) and how do we manage them? Improving the use of the CPU in Waikato DHB, New Zealand.

    PubMed

    Jade, Judith; Huggan, Paul; Stephenson, Douglas

    2015-01-01

    Chest pain is a commonly encountered presentation in the emergency department (ED). The chest pain unit at Waikato DHB is designed for patients with likely stable angina, who are at low risk of acute coronary syndrome (ACS), with a normal ECG and Troponin T, who have a history which is highly suggestive of coronary artery disease (CAD). Two issues were identified with patient care on the unit (1) the number of inappropriate admissions and (2) the number of inappropriate exercise tolerance tests. A baseline study showed that 73% of admissions did not fulfil the criteria and the majority of patients (72%) had an exercise tolerance test (ETT) irrespective of clinical picture. We delivered educational presentations to key stakeholders and the implementation of a new fast track chest pain pathway for discharging patients directly from the ED. There was an improvement in the number of patients inappropriately admitted, which fell to 61%. However, the number of inappropriate ETTs did not decrease, and were still performed on 76.9% of patients.

  17. The role of SEUSS in auxin response and floral organ patterning.

    PubMed

    Pfluger, Jennifer; Zambryski, Patricia

    2004-10-01

    Genetic and physiological analyses implicate auxin flux in patterning, initiation and growth of floral organs. Within the Arabidopsis flower, the ETTIN/ARF3 transcription factor responds to auxin to effect perianth organ number and reproductive organ differentiation. This work describes a modifier of ettin that causes filamentous, mispositioned outer whorl organs and reduced numbers of malformed stamens in the double mutant. The modifier was discovered to be a new allele of the seuss (seu) mutant. SEU encodes a novel protein that is predicted to transcriptionally co-repress the AGAMOUS floral organ identity gene. The effects of seu on ett are shown to be independent of the SEU-AG pathway. Furthermore, morphological, physiological and genetic evidence implicate SEU in auxin-regulated growth and development. seu has a pleiotropic phenotype that includes reductions in several classic auxin responses such as apical dominance, lateral root initiation, sensitivity to exogenous auxin and activation of the DR5 auxin response reporter. seu displays a synergistic interaction with the auxin response mutant pinoid, producing flowers with few outer whorl organs. Collectively, these data suggest that SEU is a novel factor affecting auxin response. A model is proposed in which SEU functions jointly with ETT in auxin response to promote floral organ patterning and growth.

  18. Exaggerated blood pressure response during the exercise treadmill test as a risk factor for hypertension

    PubMed Central

    Lima, S.G.; Albuquerque, M.F.P.M.; Oliveira, J.R.M.; Ayres, C.F.J.; Cunha, J.E.G.; Oliveira, D.F.; Lemos, R.R.; Souza, M.B.R.; Silva, O. Barbosa e

    2013-01-01

    Exaggerated blood pressure response (EBPR) during the exercise treadmill test (ETT) has been considered to be a risk factor for hypertension. The relationship of polymorphisms of the renin-angiotensin system gene with hypertension has not been established. Our objective was to evaluate whether EBPR during exercise is a clinical marker for hypertension. The study concerned a historical cohort of normotensive individuals. The exposed individuals were those who presented EBPR. At the end of the observation period (41.7 months = 3.5 years), the development of hypertension was analyzed within the two groups. Genetic polymorphisms and blood pressure behavior were assessed as independent variables, together with the classical risk factors for hypertension. The I/D gene polymorphism of the angiotensin-converting enzyme and M235T of angiotensinogen were ruled out as risk factors for hypertension. EBPR during ETT is not an independent influence on the chances of developing hypertension. No differences were observed between the hypertensive and normotensive individuals regarding gender (P = 0.655), skin color (P = 0.636), family history of hypertension (P = 0.225), diabetes mellitus (P = 0.285), or hypertriglyceridemia (P = 0.734). The risk of developing hypertension increased with increasing body mass index (BMI) and advancing age. The risk factors, which independently influenced the development of hypertension, were age and BMI. EBPR did not constitute an independent risk factor for hypertension and is probably a preclinical phase in the spectrum of normotension and hypertension. PMID:23598646

  19. Effect of nebulized eucalyptus on contamination of microbial plaque of endotracheal tube in ventilated patients

    PubMed Central

    Amini, Nazanin; Rezaei, Korosh; Yazdannik, Ahmadreza

    2016-01-01

    Background: Formation of biofilm and bacterial colonization within the endotracheal tube (ETT) are significant sources of airway contamination and play a role in the development of ventilator-associated pneumonia (VAP). This study was conducted to examine the effect of nebulized eucalyptus (NE) on bacterial colonization of ETT biofilm. Materials and Methods: We performed a randomized clinical trial in three intensive care units (ICUs) of an educational hospital. Seventy intubated patients were selected and randomly divided into intervention (n = 35) and control (n = 35) groups. The intervention group received 4 ml (5%) of eucalyptus in 6 ml normal saline every 8 h. The placebo group received only 10 ml of normal saline in the same way. On extubation, the interior of the tube was immediately sampled using a sterile swab for standard microbiological analysis. Chi-square and Fisher's exact tests were used for statistical analysis in SPSS. P values less than 0.05 were considered statistically significant. Results: In both samples, Klebsiella pneumoniae and Acinetobacter baumannii were the most frequently isolated bacteria. In the control group, heavy colonization was greater than in the intervention group (P = 0.002). The frequency of isolation of K. pneumoniae in the intervention group was lower than in the control group (P < 0.001). However, there was no difference between the two groups in other isolated bacteria. Conclusions: NE can reduce microbial contamination of the endotracheal tube biofilm in ventilated patients. Moreover, K. pneumoniae was the most sensitive to NE. PMID:27095990

  20. Who gets admitted to the Chest Pain Unit (CPU) and how do we manage them? Improving the use of the CPU in Waikato DHB, New Zealand

    PubMed Central

    Jade, Judith; Huggan, Paul; Stephenson, Douglas

    2015-01-01

    Chest pain is a commonly encountered presentation in the emergency department (ED). The chest pain unit at Waikato DHB is designed for patients with likely stable angina, who are at low risk of acute coronary syndrome (ACS), with a normal ECG and Troponin T, who have a history which is highly suggestive of coronary artery disease (CAD). Two issues were identified with patient care on the unit (1) the number of inappropriate admissions and (2) the number of inappropriate exercise tolerance tests. A baseline study showed that 73% of admissions did not fulfil the criteria and the majority of patients (72%) had an exercise tolerance test (ETT) irrespective of clinical picture. We delivered educational presentations to key stakeholders and the implementation of a new fast track chest pain pathway for discharging patients directly from the ED. There was an improvement in the number of patients inappropriately admitted, which fell to 61%. However, the number of inappropriate ETTs did not decrease, and were still performed on 76.9% of patients. PMID:26734314

  1. Who gets admitted to the Chest Pain Unit (CPU) and how do we manage them? Improving the use of the CPU in Waikato DHB, New Zealand.

    PubMed

    Jade, Judith; Huggan, Paul; Stephenson, Douglas

    2015-01-01

    Chest pain is a commonly encountered presentation in the emergency department (ED). The chest pain unit at Waikato DHB is designed for patients with likely stable angina, who are at low risk of acute coronary syndrome (ACS), with a normal ECG and Troponin T, who have a history which is highly suggestive of coronary artery disease (CAD). Two issues were identified with patient care on the unit (1) the number of inappropriate admissions and (2) the number of inappropriate exercise tolerance tests. A baseline study showed that 73% of admissions did not fulfil the criteria and the majority of patients (72%) had an exercise tolerance test (ETT) irrespective of clinical picture. We delivered educational presentations to key stakeholders and the implementation of a new fast track chest pain pathway for discharging patients directly from the ED. There was an improvement in the number of patients inappropriately admitted, which fell to 61%. However, the number of inappropriate ETTs did not decrease, and were still performed on 76.9% of patients. PMID:26734314

  2. Archaeology and direct imaging of exoplanets

    NASA Astrophysics Data System (ADS)

    Campbell, John B.

    The search for extraterrestrial technology effectively began 45 years ago with Frank Drake's Project Ozma and a radioastronomy start to the search for extraterrestrial intelligence (SETI). Eventually searches began for possible interstellar probes in stable orbits in the Solar System, as well as for infrared excesses from possible Dyson spheres round Sun-like stars. Whilst the Cold War was still underway, some scientists looked for evidence of nuclear waste dumps and nuclear wars elsewhere in the Milky Way. None of this work was carried out by archaeologists, even though by their very nature archaeologists are experts in the detection of ancient technologies. The technologies being searched for would have been partly ancient in age though advanced in techniques and science. The development of ESA's Darwin and NASA's TPF for detection and imaging of Earth-like exoplanets in our galactic neighbourhood represents an opportunity for the testing of techniques for detecting signatures of technological activities. Ideally, both Darwin and TPF might be able to provide spectroscopic data on the chemistry and biochemistry of the atmospheres of Earth-like exoplanets, and thus to detect some of the signs of life. If this can be accomplished successfully, then in theory evidence for pollution and nuclear accidents and wars should be detectable. Some infrared signatures of ETT on or round exoplanets might be detectable. Direct visual imaging of ETT structures will probably not be feasible till we have extremely powerful interstellar telescopes or actually send orbital craft.

  3. A genetic link between epigenetic repressor AS1-AS2 and a putative small subunit processome in leaf polarity establishment of Arabidopsis.

    PubMed

    Matsumura, Yoko; Ohbayashi, Iwai; Takahashi, Hiro; Kojima, Shoko; Ishibashi, Nanako; Keta, Sumie; Nakagawa, Ayami; Hayashi, Rika; Saéz-Vásquez, Julio; Echeverria, Manuel; Sugiyama, Munetaka; Nakamura, Kenzo; Machida, Chiyoko; Machida, Yasunori

    2016-01-01

    Although the DEAD-box RNA helicase family is ubiquitous in eukaryotes, its developmental role remains unelucidated. Here, we report that cooperative action between the Arabidopsis nucleolar protein RH10, an ortholog of human DEAD-box RNA helicase DDX47, and the epigenetic repressor complex of ASYMMETRIC-LEAVES1 (AS1) and AS2 (AS1-AS2) is critical to repress abaxial (ventral) genes ETT/ARF3 and ARF4, which leads to adaxial (dorsal) development in leaf primordia at shoot apices. Double mutations of rh10-1 and as2 (or as1) synergistically up-regulated the abaxial genes, which generated abaxialized filamentous leaves with loss of the adaxial domain. DDX47 is part of the small subunit processome (SSUP) that mediates rRNA biogenesis. In rh10-1 we found various defects in SSUP-related events, such as: accumulation of 35S/33S rRNA precursors; reduction in the 18S/25S ratio; and nucleolar hypertrophy. Double mutants of as2 with mutations of genes that encode other candidate SSUP-related components such as nucleolin and putative rRNA methyltransferase exhibited similar synergistic defects caused by up-regulation of ETT/ARF3 and ARF4 These results suggest a tight link between putative SSUP and AS1-AS2 in repression of the abaxial-determining genes for cell fate decisions for adaxial development. PMID:27334696

  4. Postprocedural chest radiograph: Impact on the management in critical care unit.

    PubMed

    Gupta, Prashant K; Gupta, Kumkum; Jain, Manish; Garg, Tanuj

    2014-01-01

    Postprocedural chest radiograph is done to illustrate the position of endotracheal tubes (ETTs), nasogastric and drainage tubes, indwelling catheters, and intravascular lines or any other lifesaving devices to confirm their position. These devices are intended to save life, but may be life-threatening if in the wrong place. The incidence of malposition and complications ranges from 3% to 14%, respectively. The portable chest radiograph is of tremendous value, inexpensive and can be obtained quickly at the patient's bedside in any location of the hospital. A systemic literature search was performed in PubMed and the Cochranre library by setting up the search using either single text word or combinations. Those studies were also included where the chest radiograph was compared with other imaging modalities. Its clinical efficacy, cost-effectiveness and practicality allow anesthesiologist to evaluate the post-procedural position and complications of ETT, indwelling catheters, and multi lumen intravascular lines. Knowledge of the radiological features of commonly used devices is of utmost importance. PMID:25886216

  5. Core-Level Crossing and the High-Pressure Equation of State of Heavy Elements

    NASA Astrophysics Data System (ADS)

    Wills, John

    2015-06-01

    The structural properties of the 5d transition metal osmium have recently been probed at static pressures up to ~ 770 GPa. In this study, anomalies in the hcp c/a ratio were found at pressures of in the vicinity of 150 GPa and 440 GPa. The anomaly at 150 GPa approximately coincides in pressure with an electron topological transition (ETT) observed in Density Functional Theory (DFT) band structure. However, no ETT is observed at higher pressures. Instead, we find that the anomaly in the c / a ratio of osmium is correlated with the crossing of the 5p3 / 2 and 4f7 / 2 ``core'' levels, which at this pressure are found to have bandwidths ~ .2-.3 Ry, in our DFT calculations. In this talk, I discuss the calculated structural properties and calculated equation of state of osmium and other heavy 5d elements at pressures less than 1 TPa and the effect of core-level crossing on the equation of state and structural properties of these elements.

  6. A genetic link between epigenetic repressor AS1-AS2 and a putative small subunit processome in leaf polarity establishment of Arabidopsis

    PubMed Central

    Matsumura, Yoko; Ohbayashi, Iwai; Takahashi, Hiro; Kojima, Shoko; Ishibashi, Nanako; Keta, Sumie; Nakagawa, Ayami; Hayashi, Rika; Saéz-Vásquez, Julio; Echeverria, Manuel; Sugiyama, Munetaka; Nakamura, Kenzo; Machida, Chiyoko

    2016-01-01

    ABSTRACT Although the DEAD-box RNA helicase family is ubiquitous in eukaryotes, its developmental role remains unelucidated. Here, we report that cooperative action between the Arabidopsis nucleolar protein RH10, an ortholog of human DEAD-box RNA helicase DDX47, and the epigenetic repressor complex of ASYMMETRIC-LEAVES1 (AS1) and AS2 (AS1-AS2) is critical to repress abaxial (ventral) genes ETT/ARF3 and ARF4, which leads to adaxial (dorsal) development in leaf primordia at shoot apices. Double mutations of rh10-1 and as2 (or as1) synergistically up-regulated the abaxial genes, which generated abaxialized filamentous leaves with loss of the adaxial domain. DDX47 is part of the small subunit processome (SSUP) that mediates rRNA biogenesis. In rh10-1 we found various defects in SSUP-related events, such as: accumulation of 35S/33S rRNA precursors; reduction in the 18S/25S ratio; and nucleolar hypertrophy. Double mutants of as2 with mutations of genes that encode other candidate SSUP-related components such as nucleolin and putative rRNA methyltransferase exhibited similar synergistic defects caused by up-regulation of ETT/ARF3 and ARF4. These results suggest a tight link between putative SSUP and AS1-AS2 in repression of the abaxial-determining genes for cell fate decisions for adaxial development. PMID:27334696

  7. A case of sick building syndrome in a Japanese office worker.

    PubMed

    Nakazawa, Hiroko; Ikeda, Hiroki; Yamashita, Toshio; Hara, Ichiro; Kumai, Yuko; Endo, Ginji; Endo, Yoko

    2005-04-01

    The adverse health effects caused by indoor air pollution are termed "sick building syndrome". We report such a patient whose symptoms appeared in the workplace. A 36-year-old female office worker developed nausea and headache during working hours in a refurbished office. After eight months of seeking help at other clinics or hospitals without improvement, she was referred to our hospital. At that time she reacted to the smells of various chemicals outside of the office building. Biochemical findings were all within normal ranges. Specific IgE antibody to cedar pollen was positive and the ratio of TH1/TH2 was 4.5. In the Eye Tracking Test (ETT), vertical eye movement was saccadic. Her anxiety level was very high according to the State-Trait Anxiety Inventory (STAI) questionnaire. Subjective symptoms, ETT findings and anxiety levels on STAI gradually improved during two years of follow-up. One year after the onset of her illness, the formaldehyde concentrations in the building air ranged from 0.017-0.053 ppm. Even though relatively low, chemical exposure from building materials such as formaldehyde induced a range of symptoms. Also, lack of recognition by superiors and doctors that sick building syndrome might have been the source of her illness coupled with her high state of anxiety may have exacerbated her symptoms and led to the onset of multiple chemical sensitivity. Thus psychosocial factors may contribute to sick building syndrome in the workplace.

  8. Exploring the intrinsic polar [4+2(+)] cycloaddition reactivity of gaseous carbosulfonium and carboxonium ions.

    PubMed

    Basher, Muftah M; Corilo, Yuri E; Sparrapan, Regina; Benassi, Mario; Augusti, Rodinei; Eberlin, Marcos N; Riveros, José M

    2012-11-01

    Gas-phase reactions of model carbosulfonium ions (CH(3)-S(+)=CH(2;) CH(3)CH(2)-S(+)=CH(2) and Ph-S(+)=CH(2)) and an O-analogue carboxonium ion (CH(3)-O(+)=CH(2)) with acyclic (isoprene, 1,3-butadiene, methyl vinyl ketone) and cyclic (1,3-cyclohexadiene, thiophene, furan) conjugated dienes were systematically investigated by pentaquadrupole mass spectrometry. As corroborated by B3LYP/6-311 G(d,p) calculations, the carbosulfonium ions first react at large extents with the dienes forming adducts via simple addition. The nascent adducts, depending on their stability and internal energy, react further via two competitive channels: (1) in reactions with acyclic dienes via cyclization that yields formally [4+2(+)] cycloadducts, or (2) in reactions with the cyclic dienes via dissociation by HSR loss that yields methylenation (net CH(+) transfer) products. In great contrast to its S-analogues, CH(3)-O(+)=CH(2) (as well as C(2)H(5)-O(+)=CH(2) and Ph-O(+)=CH(2) in reactions with isoprene) forms little or no adduct and proton transfer is the dominant reaction channel. Isomerization to more acidic protonated aldehydes in the course of reaction seems to be the most plausible cause of the contrasting reactivity of carboxonium ions. The CH(2)=CH-O(+)=CH(2) ion forms an abundant [4+2(+)] cycloadduct with isoprene, but similar to the behavior of such α,β-unsaturated carboxonium ions in solution, seems to occur across the C=C bond. PMID:23147832

  9. Searching for trans ethyl methyl ether in Orion KL★,★★

    PubMed Central

    Tercero, B.; Cernicharo, J.; López, A.; Brouillet, N.; Kolesniková, L.; Motiyenko, R. A.; Margulès, L.; Alonso, J. L.; Guillemin, J.-C.

    2015-01-01

    We report on the tentative detection of trans ethyl methyl ether (tEME), t-CH3CH2OCH3, through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for gauche-trans-n-propanol, Gt-n-CH3CH2CH2OH, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30 m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are ≤(4.0 ± 0.8) × 1015 cm−2 and ≤(1.0 ± 0.2)× 1015 cm−2 for tEME and Gt-n-propanol, respectively. The rotational temperature is ~100 K for both molecules. We also provide maps of CH3OCOH, CH3CH2OCOH, CH3OCH3, CH3OH, and CH3CH2OH to compare the distribution of these organic saturated O-bearing species containing methyl and ethyl groups in this region. Abundance ratios of related species and upper limits to the abundances of non-detected ethers are provided. We derive an abundance ratio N(CH3OCH3)/N(tEME) ≥ 150 in the compact ridge of Orion. PMID:26869726

  10. Intracluster ion-molecule reactions of Ti+ with ether clusters

    NASA Astrophysics Data System (ADS)

    Koo, Young-Mi; Kim, Min-Kyung; Jung, Kwang-Woo

    2005-05-01

    The intracluster ion-molecule reactions of Ti+(CH3OR)n (R = CH3, n-C3H7, n-C4H9, t-C4H9) complexes produced by the mixing of laser-vaporized plasmas and pulsed supersonic beams were investigated using a reflectron time-of-flight mass spectrometer (RTOFMS). The reactions of Ti+ with dimethyl ether clusters were found to be dominated by the CH3 elimination reaction, which produces Ti+(OCH3)m(CH3OCH3)n clusters (m = 1-3). The mass spectra resulting from the reactions of Ti+ with the other ether clusters indicate the formation of major sequences of heterocluster ions with the formula Ti+(OCH3)x(OR)y(CH3OR)n, where x = 1-3 and y = 0-2. These sequences are attributed to the insertion of Ti+ ions into the CO bonds of the ether molecules within the heteroclusters, followed by alkyl radical elimination. The prevalence of radical elimination of longer alkyl groups rather than of CH3 radicals suggests that R elimination from the [CH3OTi+R] intermediate is the preferred decomposition pathway after the selective insertion of a Ti+ ion into the CO bond of an OR group. Our results also indicate that consecutive insertions of a Ti+ ion can occur for up to three precursor molecules. The experiments also show that the molecular eliminations of H2 and alkanes, resulting from CH and CC bond insertion, respectively, play an increasingly important role as the size of the alkyl group (R) in the ether molecule increases. The reaction energetics and the formation mechanisms of the observed heterocluster ions are also discussed.

  11. Kinetics of the degradation of sulfur mustard on ambient and moist concrete.

    PubMed

    Brevett, Carol A S; Sumpter, Kenneth B; Nickol, Robert G

    2009-02-15

    The rate of degradation of the chemical warfare agent sulfur mustard, bis(2-chloroethyl) sulfide, was measured on ambient and moist concrete using (13)C Solid State Magic Angle Spinning Nuclear Magnetic Resonance (SSMAS NMR). Three samples of concrete made by the same formulation, but differing in age and alkalinity were used. The sulfur mustard eventually degraded to thiodiglycol and 1,4-oxathiane via the intermediate sulfonium ions CH-TG, H-TG, H-2TG and O(CH(2)CH(2))(2)S(+)CH(2)CH(2)OH on all of the concrete samples, and in addition formed 8-31% vinyl moieties on the newer, more alkaline concrete samples. This is the first observation of the formation of O(CH(2)CH(2))(2)S(+)CH(2)CH(2)OH on a solid substrate. The addition of 2-chloroethanol to concrete on which mustard had fully degraded to thiodiglycol and 1,4-oxathiane resulted in the formation of O(CH(2)CH(2))(2)S(+)CH(2)CH(2)OH, thus demonstrating the reversibility of sulfur mustard degradation pathways. The sulfur mustard degradation half-lives on ambient concrete at 22 degrees C ranged from 3.5 to 54 weeks. When the substrates were moistened, the degradation half-lives at 22 degrees C ranged from 75 to 350h. The degradation of sulfur mustard occurred more quickly at elevated temperatures and with added water. The non-volatile toxic sulfonium ions persisted for months to years on concrete at 22 degrees C and weeks to months on concrete at 35 degrees C, before decomposing to the relatively non-toxic compounds thiodiglycol and 1,4-oxathiane. PMID:18584953

  12. Phospholipase C and myosin light chain kinase inhibition define a common step in actin regulation during cytokinesis

    PubMed Central

    Wong, Raymond; Fabian, Lacramioara; Forer, Arthur; Brill, Julie A

    2007-01-01

    Background Phosphatidylinositol 4,5-bisphosphate (PIP2) is required for successful completion of cytokinesis. In addition, both PIP2 and phosphoinositide-specific phospholipase C (PLC) have been localized to the cleavage furrow of dividing mammalian cells. PLC hydrolyzes PIP2 to yield diacylglycerol (DAG) and inositol trisphosphate (IP3), which in turn induces calcium (Ca2+) release from the ER. Several studies suggest PIP2 must be hydrolyzed continuously for continued cleavage furrow ingression. The majority of these studies employ the N-substituted maleimide U73122 as an inhibitor of PLC. However, the specificity of U73122 is unclear, as its active group closely resembles the non-specific alkylating agent N-ethylmaleimide (NEM). In addition, the pathway by which PIP2 regulates cytokinesis remains to be elucidated. Results Here we compared the effects of U73122 and the structurally unrelated PLC inhibitor ET-18-OCH3 (edelfosine) on cytokinesis in crane-fly and Drosophila spermatocytes. Our data show that the effects of U73122 are indeed via PLC because U73122 and ET-18-OCH3 produced similar effects on cell morphology and actin cytoskeleton organization that were distinct from those caused by NEM. Furthermore, treatment with the myosin light chain kinase (MLCK) inhibitor ML-7 caused cleavage furrow regression and loss of both F-actin and phosphorylated myosin regulatory light chain from the contractile ring in a manner similar to treatment with U73122 and ET-18-OCH3. Conclusion We have used multiple inhibitors to examine the roles of PLC and MLCK, a predicted downstream target of PLC regulation, in cytokinesis. Our results are consistent with a model in which PIP2 hydrolysis acts via Ca2+ to activate myosin via MLCK and thereby control actin dynamics during constriction of the contractile ring. PMID:17509155

  13. Hydrogen-bonding Interactions between Apigenin and Ethanol/Water: A Theoretical Study

    PubMed Central

    Zheng, Yan-Zhen; Zhou, Yu; Liang, Qin; Chen, Da-Fu; Guo, Rui; Lai, Rong-Cai

    2016-01-01

    In this work, hydrogen-bonding interactions between apigenin and water/ethanol were investigated from a theoretical perspective using quantum chemical calculations. Two conformations of apigenin molecule were considered in this work. The following results were found. (1) For apigenin monomer, the molecular structure is non-planar, and all of the hydrogen and oxygen atoms can be hydrogen-bonding sites. (2) Eight and seven optimized geometries are obtained for apigenin (I)–H2O/CH3CH2OH and apigenin (II)–H2O/CH3CH2OH complexes, respectively. In apigenin, excluding the aromatic hydrogen atoms in the phenyl substituent, all other hydrogen atoms and the oxygen atoms form hydrogen-bonds with H2O and CH3CH2OH. (3) In apigenin–H2O/CH3CH2OH complexes, the electron density and the E(2) in the related localized anti-bonding orbital are increased upon hydrogen-bond formation. These are the cause of the elongation and red-shift of the X−H bond. The sum of the charge change transfers from the hydrogen-bond acceptor to donor. The stronger interaction makes the charge change more intense than in the less stable structures. (4) Most of the hydrogen-bonds in the complexes are electrostatic in nature. However, the C4−O5···H, C9−O4···H and C13−O2···H hydrogen-bonds have some degree of covalent character. Furthermore, the hydroxyl groups of the apigenin molecule are the preferred hydrogen-bonding sites. PMID:27698481

  14. CNN pincer ruthenium catalysts for hydrogenation and transfer hydrogenation of ketones: experimental and computational studies.

    PubMed

    Baratta, Walter; Baldino, Salvatore; Calhorda, Maria José; Costa, Paulo J; Esposito, Gennaro; Herdtweck, Eberhardt; Magnolia, Santo; Mealli, Carlo; Messaoudi, Abdelatif; Mason, Sax A; Veiros, Luis F

    2014-10-13

    Reaction of [RuCl(CNN)(dppb)] (1-Cl) (HCNN=2-aminomethyl-6-(4-methylphenyl)pyridine; dppb=Ph2 P(CH2 )4 PPh2 ) with NaOCH2 CF3 leads to the amine-alkoxide [Ru(CNN)(OCH2 CF3 )(dppb)] (1-OCH2 CF3 ), whose neutron diffraction study reveals a short RuO⋅⋅⋅HN bond length. Treatment of 1-Cl with NaOEt and EtOH affords the alkoxide [Ru(CNN)(OEt)(dppb)]⋅(EtOH)n (1-OEt⋅n EtOH), which equilibrates with the hydride [RuH(CNN)(dppb)] (1-H) and acetaldehyde. Compound 1-OEt⋅n EtOH reacts reversibly with H2 leading to 1-H and EtOH through dihydrogen splitting. NMR spectroscopic studies on 1-OEt⋅n EtOH and 1-H reveal hydrogen bond interactions and exchange processes. The chloride 1-Cl catalyzes the hydrogenation (5 atm of H2 ) of ketones to alcohols (turnover frequency (TOF) up to 6.5×10(4) h(-1) , 40 °C). DFT calculations were performed on the reaction of [RuH(CNN')(dmpb)] (2-H) (HCNN'=2-aminomethyl-6-(phenyl)pyridine; dmpb=Me2 P(CH2 )4 PMe2 ) with acetone and with one molecule of 2-propanol, in alcohol, with the alkoxide complex being the most stable species. In the first step, the Ru-hydride transfers one hydrogen atom to the carbon of the ketone, whereas the second hydrogen transfer from NH2 is mediated by the alcohol and leads to the key "amide" intermediate. Regeneration of the hydride complex may occur by reaction with 2-propanol or with H2 ; both pathways have low barriers and are alcohol assisted. PMID:25195979

  15. Kinetics of the degradation of sulfur mustard on ambient and moist concrete.

    PubMed

    Brevett, Carol A S; Sumpter, Kenneth B; Nickol, Robert G

    2009-02-15

    The rate of degradation of the chemical warfare agent sulfur mustard, bis(2-chloroethyl) sulfide, was measured on ambient and moist concrete using (13)C Solid State Magic Angle Spinning Nuclear Magnetic Resonance (SSMAS NMR). Three samples of concrete made by the same formulation, but differing in age and alkalinity were used. The sulfur mustard eventually degraded to thiodiglycol and 1,4-oxathiane via the intermediate sulfonium ions CH-TG, H-TG, H-2TG and O(CH(2)CH(2))(2)S(+)CH(2)CH(2)OH on all of the concrete samples, and in addition formed 8-31% vinyl moieties on the newer, more alkaline concrete samples. This is the first observation of the formation of O(CH(2)CH(2))(2)S(+)CH(2)CH(2)OH on a solid substrate. The addition of 2-chloroethanol to concrete on which mustard had fully degraded to thiodiglycol and 1,4-oxathiane resulted in the formation of O(CH(2)CH(2))(2)S(+)CH(2)CH(2)OH, thus demonstrating the reversibility of sulfur mustard degradation pathways. The sulfur mustard degradation half-lives on ambient concrete at 22 degrees C ranged from 3.5 to 54 weeks. When the substrates were moistened, the degradation half-lives at 22 degrees C ranged from 75 to 350h. The degradation of sulfur mustard occurred more quickly at elevated temperatures and with added water. The non-volatile toxic sulfonium ions persisted for months to years on concrete at 22 degrees C and weeks to months on concrete at 35 degrees C, before decomposing to the relatively non-toxic compounds thiodiglycol and 1,4-oxathiane.

  16. Hydrogen-bonding Interactions between Apigenin and Ethanol/Water: A Theoretical Study

    NASA Astrophysics Data System (ADS)

    Zheng, Yan-Zhen; Zhou, Yu; Liang, Qin; Chen, Da-Fu; Guo, Rui; Lai, Rong-Cai

    2016-10-01

    In this work, hydrogen-bonding interactions between apigenin and water/ethanol were investigated from a theoretical perspective using quantum chemical calculations. Two conformations of apigenin molecule were considered in this work. The following results were found. (1) For apigenin monomer, the molecular structure is non-planar, and all of the hydrogen and oxygen atoms can be hydrogen-bonding sites. (2) Eight and seven optimized geometries are obtained for apigenin (I)–H2O/CH3CH2OH and apigenin (II)–H2O/CH3CH2OH complexes, respectively. In apigenin, excluding the aromatic hydrogen atoms in the phenyl substituent, all other hydrogen atoms and the oxygen atoms form hydrogen-bonds with H2O and CH3CH2OH. (3) In apigenin–H2O/CH3CH2OH complexes, the electron density and the E(2) in the related localized anti-bonding orbital are increased upon hydrogen-bond formation. These are the cause of the elongation and red-shift of the X‑H bond. The sum of the charge change transfers from the hydrogen-bond acceptor to donor. The stronger interaction makes the charge change more intense than in the less stable structures. (4) Most of the hydrogen-bonds in the complexes are electrostatic in nature. However, the C4‑O5···H, C9‑O4···H and C13‑O2···H hydrogen-bonds have some degree of covalent character. Furthermore, the hydroxyl groups of the apigenin molecule are the preferred hydrogen-bonding sites.

  17. Inositol triphosphate participates in an oestradiol nongenomic signalling pathway involved in accelerated oviductal transport in cycling rats.

    PubMed

    Orihuela, Pedro A; Parada-Bustamante, Alexis; Zuñiga, Lidia M; Croxatto, Horacio B

    2006-03-01

    Oestradiol (E(2)) accelerates oviductal transport of oocytes in cycling rats through a nongenomic pathway that involves the cAMP-PKA signalling cascade. Here we examined the role of the inositol triphosphate (IP3) and mitogen-activated protein kinase (MAPK) signalling cascades in this nongenomic pathway. Oestrous rats were injected with E(2) s.c. and intrabursally (i.b) with the selective inhibitors of phospholipase C (PLC) ET-18-OCH(3) or MAPK PD98059. The number of eggs in the oviduct assessed 24 h later showed that ET-18-OCH(3) blocked E(2)-induced egg transport acceleration, whereas PD98059 had no effect. Other oestrous rats were treated with E(2) s.c. and 1, 3 or 6 h later oviducts were excised and the levels of IP3 and phosphorylated MAPK p44/42 (activated) were determined by radioreceptor assay and western blot, respectively. Oestradiol administration increased IP3 level at 1 and 6 h after treatment, whereas activated MAPK p44/42 level was unchanged. Finally, we explored whether cAMP-PKA and PLC-IP3 signalling cascades are coupled. Inhibition of adenylyl cyclase by i.b. injection of SQ 22536 blocked the increase of IP3 levels induced by E(2), while inhibition of PLC by ET-18-OCH(3) had no effect on E(2)-induced PKA activity. Furthermore, activation of adenylyl cyclase by Forskolin increased oviductal IP3 levels. Thus, activation of PLC-IP3 by E(2) requires previous stimulation of cAMP-PKA. We conclude that the nongenomic pathway utilised by E(2) to accelerate oviductal transport of oocytes in cycling rats involves successive activation of the cAMP-PKA and PLC-IP3 signalling cascades and does not require activation of MAPK. These findings clearly illustrate a non-genomic pathway triggered by E(2) that regulates a complex physiologic process accomplished by an entire organ.

  18. Preventing and curing citrulline-induced autoimmune arthritis in a humanized mouse model using a Th2-polarizing iNKT cell agonist.

    PubMed

    Walker, Kyle M; Rytelewski, Mateusz; Mazzuca, Delfina M; Meilleur, Shannon A; Mannik, Lisa A; Yue, David; Brintnell, William C; Welch, Ian; Cairns, Ewa; Haeryfar, S M Mansour

    2012-07-01

    Invariant natural killer T (iNKT) cells are innate lymphocytes with unique reactivity to glycolipid antigens bound to non-polymorphic CD1d molecules. They are capable of rapidly releasing pro- and/or anti-inflammatory cytokines and constitute attractive targets for immunotherapy of a wide range of diseases including autoimmune disorders. In this study, we have explored the beneficial effects of OCH, a Th2-polarizing glycolipid agonist of iNKT cells, in a humanized mouse model of rheumatoid arthritis (RA) in which citrullinated human proteins are targeted by autoaggressive immune responses in mice expressing an RA susceptibility human leukocyte antigen (HLA) DR4 molecule. We found for the first time that treatment with OCH both prevents and cures citrulline-induced autoimmune arthritis as evidenced by resolved ankle swelling and reversed histopathological changes associated with arthritis. Also importantly, OCH treatment blocked the arthritogenic capacity of citrullinated antigen-experienced splenocytes without compromising their global responsiveness or altering the proportion of splenic naturally occurring CD4(+)CD25(+)FoxP3(+) regulatory T cells. Interestingly, administering the Th1-promoting iNKT cell glycolipid ligand α-C-galactosylceramide into HLA-DR4 transgenic mice increased the incidence of arthritis in these animals and exacerbated their clinical symptoms, strongly suggesting a role for Th1 responses in the pathogenesis of citrulline-induced arthritis. Therefore, our findings indicate a role for Th1-mediated immunopathology in citrulline-induced arthritis and provide the first evidence that iNKT cell manipulation by Th2-skewing glycolipids may be of therapeutic value in this clinically relevant model, a finding that is potentially translatable to human RA. PMID:21912419

  19. Metallacryptate single-molecule magnets: effect of lower molecular symmetry on blocking temperature.

    PubMed

    Zaleski, Curtis M; Depperman, Ezra C; Dendrinou-Samara, Catherine; Alexiou, Maria; Kampf, Jeff W; Kessissoglou, Dimitris P; Kirk, Martin L; Pecoraro, Vincent L

    2005-09-21

    The structural characterization of complexes [Mn(II)4Mn(III)22(pdol)12(OCH3)12(O)16(N3)6] (1) and [Mn(II)4Mn(III)22(pdol)12(OCH3)12(O)16(OH)2(H3O)(OCH3)3].ClO4.5CH3OH (2), where pdol(2-) is di-2-pyridyl methanediol, reveals that each has a metallacryptand shell that encapsulates a manganese oxide core. Variable-temperature direct current magnetic susceptibility measurements on 2 indicate a paramagnetic ground state that results from an overall antiferromagnetic interaction in the cluster, with chiT values decreasing from 300 K (51.2 cm3 K mol(-1)) to 2 K (19.8 cm3 K mol(-1)). Variable-temperature alternating current magnetic susceptibility measurements imply that both 1 and 2 behave as single-molecule magnets. Fitting the frequency-dependent out-of-phase magnetic susceptibility to the Arrhenius equation yields an effective energy barrier, Ueff, to magnetization relaxation of 16.5 +/- 0.7 K (11.5 +/- 0.5 cm(-1)) for 1 and 36.2 +/- 2.0 K (25.1 +/- 1.4 cm(-1)) for 2. The larger value for 2 is in agreement with the lower molecular symmetry, larger magnetoanisotropy, and higher ground spin state of 2 compared to those of 1. This observation suggests a new strategy for increasing the blocking temperatures in high-nuclearity manganese clusters.

  20. Detection and Identification of the Keto-Hydroperoxide (HOOCH2OCHO) and Other Intermediates during Low-Temperature Oxidation of Dimethyl Ether.

    PubMed

    Moshammer, Kai; Jasper, Ahren W; Popolan-Vaida, Denisia M; Lucassen, Arnas; Diévart, Pascal; Selim, Hatem; Eskola, Arkke J; Taatjes, Craig A; Leone, Stephen R; Sarathy, S Mani; Ju, Yiguang; Dagaut, Philippe; Kohse-Höinghaus, Katharina; Hansen, Nils

    2015-07-16

    In this paper we report the detection and identification of the keto-hydroperoxide (hydroperoxymethyl formate, HPMF, HOOCH2OCHO) and other partially oxidized intermediate species arising from the low-temperature (540 K) oxidation of dimethyl ether (DME). These observations were made possible by coupling a jet-stirred reactor with molecular-beam sampling capabilities, operated near atmospheric pressure, to a reflectron time-of-flight mass spectrometer that employs single-photon ionization via tunable synchrotron-generated vacuum-ultraviolet radiation. On the basis of experimentally observed ionization thresholds and fragmentation appearance energies, interpreted with the aid of ab initio calculations, we have identified HPMF and its conceivable decomposition products HC(O)O(O)CH (formic acid anhydride), HC(O)OOH (performic acid), and HOC(O)OH (carbonic acid). Other intermediates that were detected and identified include HC(O)OCH3 (methyl formate), cycl-CH2-O-CH2-O- (1,3-dioxetane), CH3OOH (methyl hydroperoxide), HC(O)OH (formic acid), and H2O2 (hydrogen peroxide). We show that the theoretical characterization of multiple conformeric structures of some intermediates is required when interpreting the experimentally observed ionization thresholds, and a simple method is presented for estimating the importance of multiple conformers at the estimated temperature (∼100 K) of the present molecular beam. We also discuss possible formation pathways of the detected species: for example, supported by potential energy surface calculations, we show that performic acid may be a minor channel of the O2 + ĊH2OCH2OOH reaction, resulting from the decomposition of the HOOCH2OĊHOOH intermediate, which predominantly leads to the HPMF.

  1. Detection and Identification of the Keto-Hydroperoxide (HOOCH2OCHO) and Other Intermediates during Low-Temperature Oxidation of Dimethyl Ether.

    PubMed

    Moshammer, Kai; Jasper, Ahren W; Popolan-Vaida, Denisia M; Lucassen, Arnas; Diévart, Pascal; Selim, Hatem; Eskola, Arkke J; Taatjes, Craig A; Leone, Stephen R; Sarathy, S Mani; Ju, Yiguang; Dagaut, Philippe; Kohse-Höinghaus, Katharina; Hansen, Nils

    2015-07-16

    In this paper we report the detection and identification of the keto-hydroperoxide (hydroperoxymethyl formate, HPMF, HOOCH2OCHO) and other partially oxidized intermediate species arising from the low-temperature (540 K) oxidation of dimethyl ether (DME). These observations were made possible by coupling a jet-stirred reactor with molecular-beam sampling capabilities, operated near atmospheric pressure, to a reflectron time-of-flight mass spectrometer that employs single-photon ionization via tunable synchrotron-generated vacuum-ultraviolet radiation. On the basis of experimentally observed ionization thresholds and fragmentation appearance energies, interpreted with the aid of ab initio calculations, we have identified HPMF and its conceivable decomposition products HC(O)O(O)CH (formic acid anhydride), HC(O)OOH (performic acid), and HOC(O)OH (carbonic acid). Other intermediates that were detected and identified include HC(O)OCH3 (methyl formate), cycl-CH2-O-CH2-O- (1,3-dioxetane), CH3OOH (methyl hydroperoxide), HC(O)OH (formic acid), and H2O2 (hydrogen peroxide). We show that the theoretical characterization of multiple conformeric structures of some intermediates is required when interpreting the experimentally observed ionization thresholds, and a simple method is presented for estimating the importance of multiple conformers at the estimated temperature (∼100 K) of the present molecular beam. We also discuss possible formation pathways of the detected species: for example, supported by potential energy surface calculations, we show that performic acid may be a minor channel of the O2 + ĊH2OCH2OOH reaction, resulting from the decomposition of the HOOCH2OĊHOOH intermediate, which predominantly leads to the HPMF. PMID:25695304

  2. Inference of nitrogen cycling in three watersheds of northern Florida, USA, by multivariate statistical analysis

    NASA Astrophysics Data System (ADS)

    Fu, Ji-Meng; Winchester, John W.

    1994-03-01

    Nitrogen in fresh waters of three rivers in northern Florida - the Apalachicola-Chattahoochee-Flint (ACF) River system, Ochlockonee (Och), and Sopchoppy (Sop) - is inferred to be derived mostly from atmospheric deposition. Because the N:P mole ratios in the rivers are nearly three times higher than the Redfield ratio for aquatic photosynthesis, N is saturated in the ecosystems, not a limiting nutrient, although it may be chemically transformed. Absolute principal component analysis (APCA), a receptor model, was applied to many years of monitoring data for Apalachicola River water and rainfall over its basin in order to better understand aquatic chemistry of nitrogen in the watershed. The APCA model describes the river water as mainly a mixture of components with compositions resembling fresh rain, aged rain, and groundwater. In the fresh rain component, the ratio of atmospheric nitrate to sulfate is close to that in rainwater, as if some samples had been collected following very recent rainfall. The aged rain component of the river water is distinguished by a low NO 3-/SO 42- ratio, signifying an atmospheric source but with most of its nitrate having been lost or transformed. The groundwater component, inferred from its concentration to contribute on average about one fourth of the river water, contains abundant Ca 2+ but no detectable nitrogen. Results similar to ACF were obtained for Sop and Och, though Och exhibits some association of NO 3- with the Ca 2+-rich component. Similar APCA of wet precipitation resolves mainly components that represent acid rain, with NO 3-, SO 42- and NH 4+ and sea salt, with Na +, Cl - and Mg 2+. Inland, the acid rain component is relatively more prominent and Cl - is depleted, while at atmospheric monitoring sites nearer the coastal region sea salt tends to be more prominent.

  3. Multiheteromacrocycles that Complex Metal Ions. Second Progress Report, 1 May 1975 -- 30 April 1976

    DOE R&D Accomplishments Database

    Cram, D. J.

    1976-01-15

    Objective is to develop cyclic and polycyclic host organic compounds to complex and lipophilize metal ions. Macrorings were synthesized: (OCH{sub 2} CH{sub 2} O CH{sub 2}COCH{sub 2} COCH{sub 2}){sub 2} and (OCH{sub 2} CH{sub 2} O CH{sub 2} COCH{sub 2} COCH{sub 2}){sub 3}. The smaller ring complexes divalent metals 10{sup 1+9} times better than the open-chain model CH{sub 3} O CH{sub 2} CO CH{sub 2} COCH{sub 2} O CH{sub 3}, and the order in which metal ions are complexed is Cu{sup 2+}, UO{sub 2}{sup 2+} greater than Ni{sup 2+} greater than Fe{sup 2+}, Co{sup 2+}, Zn{sup 2+}, Cd{sup 2+} greater than Mn{sup 2+}. The UO{sub 2}{sup 2+} and Cu{sup 2+} complexes were isolated and characterized. The larger ring complexes trivalent metals 10{sup 0.9-1.7} times better than the open- chain model compound, and the order is La{sup 3+}, Ce{sup 3+} greater than Cr{sup 3+}. Five other macrocycles were also synthesized, and their binding constants with Na, K, NH{sub 4}, and Cs picrates were measured. Six compounds containing one macroring and two inward-pointing ArOH or ArOCH{sub 3} groups were also prepared and tested for binding of Li, Na, K, Rb, and NH{sub 4} picrates. Racemic compounds containing two binaphthyls and its sulfur analog were prepared. Cage-shaped multiheteromacrocycles containing ten O ligand sites or four S and six O ligand sites were prepared and the binding capability of the first compound for picrates studied. Two ring systems with phosphonate ester groups were also prepared. (DLC)

  4. The effect of solution chemistry on the preparation of MgAl{sub 2}O{sub 4} by hydrothermal-assisted sol-gel processing

    SciTech Connect

    Amini, M.M. . E-mail: m-pouramini@cc.sbu.ac.ir; Mirzaee, M.; Sepanj, N.

    2007-03-22

    Preparation of magnesium aluminate spinel powder by hydrothermal-assisted sol-gel processing from MgAl{sub 2}(OCH{sub 2}CH{sub 2}OR){sub 8}, R=CH{sub 3} (1), CH{sub 2}CH{sub 2}OCH{sub 3} (2), MgAl{sub 2}[OCH(CH{sub 3}){sub 2}]{sub 8} (3) and MgAl{sub 2}(O- {sup s}Bu){sub 8} (4) in toluene and parent alcohol has been investigated. Coordination status of aluminum atom in precursors was determined by {sup 27}Al NMR and correlation between coordination number of aluminum and development of spinel phase in hydrothermal-assisted sol-gel processing has been studied. The gels obtained from hydrothermal-assisted hydrolysis of magnesium-aluminum alkoxides that contain six-coordinated aluminum atoms in solution (1 and 2) after calcination at 700 deg. C resulted in the formation of pure spinel phase, whereas in similar hydrolysis and calcination processes of precursors that contain four-coordinated aluminum (3 and 4) spinel phase forms along with some Al{sub 2}O{sub 3} and MgO. Selected powders obtained from hydrothermal-assisted sol-gel processing were characterized by thermal analysis (TGA/DSC), X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). Results indicate that the coordination status of aluminum in the precursor is very crucial for the formation of pure phase spinel. The morphology of prepared spinels was studied by SEM and the results showed that the solvent in hydrothermal-assisted sol-gel processing has a marked effect on the morphology of the resulting MgAl{sub 2}O{sub 4}. In hydrothermal-assisted sol-gel processing of aluminum-magnesium alkoxides in hydrophobic solvent, spherical particles are formed, while in the parent alcohol, non-spherical powders are formed.

  5. FTIR gas-phase kinetic study on the reactions of some acrylate esters with OH radicals and Cl atoms.

    PubMed

    Moreno, A; Gallego-Iniesta, M P; Taccone, R; Martín, M P; Cabañas, B; Salgado, M S

    2014-10-01

    Acrylate esters are α,β-unsaturated esters that contain vinyl groups directly attached to the carbonyl carbon. These compounds are widely used in the production of plastics and resins. Atmospheric degradation processes of these compounds are currently not well understood. The kinetics of the gas phase reactions of OH radicals with methyl 3-methylacrylate and methyl 3,3-dimethylacrylate were determined using the relative rate technique in a 50 L Pyrex photoreactor using in situ FTIR spectroscopy at room temperature (298 ± 2 K) and atmospheric pressure (708 ± 8 Torr) with air as the bath gas. Rate coefficients obtained were (in units cm(3) molecule(-1) s(-1)): (3.27 ± 0.33) × 10(-11) and (4.43 ± 0.42) × 10(-11), for CH3CH═CHC(O)OCH3 and (CH3)2CH═CHC(O)OCH3, respectively. The same technique was used to study the gas phase reactions of hexyl acrylate and ethyl hexyl acrylate with OH radicals and Cl atoms. In the experiments with Cl, N2 and air were used as the bath gases. The following rate coefficients were obtained (in cm(3) molecule(-1) s(-1)): k3 (CH2═CHC(O)O(CH2)5CH3 + Cl) = (3.31 ± 0.31) × 10(-10), k4(CH2═CHC(O)OCH2CH(CH2CH3)(CH2)3CH3 + Cl) = (3.46 ± 0.31) × 10(-10), k5(CH2═CHC(O)O(CH2)5CH3 + OH) = (2.28 ± 0.23) × 10(-11), and k6(CH2═CHC(O)OCH2CH(CH2CH3)(CH2)3CH3 + OH) = (2.74 ± 0.26) × 10(-11). The reactivity increased with the number of methyl substituents on the double bond and with the chain length of the alkyl group in -C(O)OR. Estimations of the atmospheric lifetimes clearly indicate that the dominant atmospheric loss process for these compounds is their daytime reaction with the hydroxyl radical. In coastal areas and in some polluted environments, Cl atom-initiated degradation of these compounds can be significant, if not dominant. Maximum Incremental Reactivity (MIR) index and global warming potential (GWP) were also calculated, and it was concluded that these compounds have significant MIR values, but they do

  6. (R)-2,2'-Bis(meth-oxy-meth-oxy)-1,1'-binaphth-yl.

    PubMed

    Zhou, Liang; Eli, Wumanjiang

    2012-05-01

    The asymmetric unit of the title compound, C(24)H(22)O(4), contains two independent mol-ecules in both of which the naphthalene ring systems adopts a transoid arrangement. The dihedral angles between the naphthalene ring system in the two mol-ecules are 83.0 (1) and 89.0 (1)°. There are slight differences in the C(H(3))-O-C(H(2))-O- torsion angles of the eqivalent meth-oxy-meth-oxy groups. In the crystal, weak C-H⋯O hydrogen bonds are present.

  7. Atmospheric chemistry of a model biodiesel fuel, CH3C(O)O(CH2)2OC(O)CH3: kinetics, mechanisms, and products of Cl atom and OH radical initiated oxidation in the presence and absence of NOx.

    PubMed

    Hurley, M D; Ball, J C; Wallington, T J; Toft, A; Nielsen, O J; Bertman, S; Perkovic, M

    2007-04-01

    Relative rate techniques were used to study the kinetics of the reactions of Cl atoms and OH radicals with ethylene glycol diacetate, CH3C(O)O(CH2)2OC(O)CH3, in 700 Torr of N2/O2 diluent at 296 K. The rate constants measured were k(Cl + CH3C(O)O(CH2)2OC(O)CH3) = (5.7 +/- 1.1) x 10(-12) and k(OH + CH3C(O)O(CH2)2OC(O)CH3) = (2.36 +/- 0.34) x 10(-12) cm3 molecule-1 s-1. Product studies of the Cl atom initiated oxidation of ethylene glycol diacetate in the absence of NO in 700 Torr of O2/N2 diluent at 296 K show the primary products to be CH3C(O)OC(O)CH2OC(O)CH3, CH3C(O)OC(O)H, and CH3C(O)OH. Product studies of the Cl atom initiated oxidation of ethylene glycol diacetate in the presence of NO in 700 Torr of O2/N2 diluent at 296 K show the primary products to be CH3C(O)OC(O)H and CH3C(O)OH. The CH3C(O)OCH2O* radical is formed during the Cl atom initiated oxidation of ethylene glycol diacetate, and two loss mechanisms were identified: reaction with O2 to give CH3C(O)OC(O)H and alpha-ester rearrangement to give CH3C(O)OH and HC(O) radicals. The reaction of CH3C(O)OCH2O2* with NO gives chemically activated CH3C(O)OCH2O* radicals which are more likely to undergo decomposition via the alpha-ester rearrangement than CH3C(O)OCH2O* radicals produced in the peroxy radical self-reaction.

  8. Propenyl ether monomers for photopolymerization

    DOEpatents

    Crivello, James V.

    1996-01-01

    Propenyl ether monomers of formula V A(OCH.dbd.CHCH.sub.3).sub.n wherein n is an integer from one to six and A is selected from cyclic ethers, polyether and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of formula V together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

  9. Process for making propenyl ethers and photopolymerizable compositions containing them

    DOEpatents

    Crivello, James V.

    1996-01-01

    Propenyl ether monomers of formula V A(OCH.dbd.CHCH.sub.3).sub.n wherein n is an integer from one to six and A is selected from cyclic ethers, polyether and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of formula V together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

  10. Characterization of supramolecular (H2O)18 water morphology and water-methanol (H2O)15(CH3OH)3 clusters in a novel phosphorus functionalized trimeric amino acid host.

    PubMed

    Raghuraman, Kannan; Katti, Kavita K; Barbour, Leonard J; Pillarsetty, Nagavarakishore; Barnes, Charles L; Katti, Kattesh V

    2003-06-11

    Phosphorus functionalized trimeric alanine compounds (l)- and (d)-P(CH(2)NHCH(CH(3))COOH)(3) 2 are prepared in 90% yields by the Mannich reaction of Tris(hydroxymethyl)phosphine 1 with (l)- or (d)- Alanine in aqueous media. The hydration properties of (l)-2 and (d)-2 in water and water-methanol mixtures are described. The crystal structure analysis of (l)-2.4H(2)O, reveals that the alanine molecules pack to form two-dimensional bilayers running parallel to (001). The layered structural motif depicts two closely packed monolayers of 2 each oriented with its phosphorus atoms projected at the center of the bilayer and adjacent monolayers are held together by hydrogen bonds between amine and carboxylate groups. The water bilayers are juxtaposed with the H-bonded alanine trimers leading to 18-membered (H(2)O)(18) water rings. Exposure of aqueous solution of (l)-2 and (d)-2 to methanol vapors resulted in closely packed (l)-2 and (d)-2 solvated with mixed water-methanol (H(2)O)(15)(CH(3)OH)(3) clusters. The O-O distances in the mixed methanol-water clusters of (l)-2.3H(2)O.CH(3)OH and (d)-2.3H(2)O.CH(3)OH (O-O(average) = 2.857 A) are nearly identical to the O-O distance observed in the supramolecular (H(2)O)(18) water structure (O-O(average) = 2.859 A) implying the retention of the hydrogen bonded structure in water despite the accommodation of hydrophobic methanol groups within the supramolecular (H(2)O)(15)(CH(3)OH)(3) framework. The O-O distances in (l)-2.3H(2)O.CH(3)OH and (d)-2.3H(2)O.CH(3)OH and in (H(2)O)(18) are very close to the O-O distance reported for liquid water (2.85 A).

  11. New sandwich-type lanthanide complexes based on closed-macrocyclic Schiff base and phthalocyanine molecules.

    PubMed

    Gao, Feng; Feng, Xiaowan; Yang, Liu; Chen, Xiaoyu

    2016-04-25

    Two new sandwich-type lanthanide complexes with the general formula [(Pc)2Ln3(L)(OAc)(OCH3)2] (Ln(3+) = Dy(3+) () and Er(3+) ()) were successfully synthesized and structurally characterized based on closed-macrocyclic Schiff base and phthalocyanine molecules. The magnetic properties and structure-property relationship in this multi-decker system were investigated. Interestingly, the corresponding dysprosium complex shows typical single-molecule magnetic behavior with ferromagnetic dipole-dipole interactions and the slow relaxation of magnetization. PMID:27044594

  12. Increasing the activity and enantioselectivity of lipases by sol-gel immobilization: further advancements of practical interest

    NASA Astrophysics Data System (ADS)

    Tielmann, Patrick; Kierkels, Hans; Zonta, Albin; Ilie, Adriana; Reetz, Manfred T.

    2014-05-01

    The entrapment of lipases in hydrophobic silicate matrices formed by sol-gel mediated hydrolysis of RSi(OCH3)3/Si(OCH3)4 as originally reported in 1996 has been improved over the years by a number of modifications. In the production of second-generation sol-gel lipase immobilizates, a variety of additives during the sol-gel process leads to increased activity and enhanced stereoselectivity in esterifying kinetic resolution. Recent advances in this type of lipase immobilization are reviewed here, in addition to new results regarding the sol-gel entrapment of the lipase from Burkholderia cepacia. It constitutes an excellent heterogeneous biocatalyst in the acylating kinetic resolution of two synthetically and industrially important chiral alcohols, rac-sulcatol and rac-trans-2-methoxycyclohexanol. The observation that the catalyst can be used 10 times in recycling experiments without losing its significant activity or enantioselectivity demonstrates the practical viability of the sol-gel approach.The entrapment of lipases in hydrophobic silicate matrices formed by sol-gel mediated hydrolysis of RSi(OCH3)3/Si(OCH3)4 as originally reported in 1996 has been improved over the years by a number of modifications. In the production of second-generation sol-gel lipase immobilizates, a variety of additives during the sol-gel process leads to increased activity and enhanced stereoselectivity in esterifying kinetic resolution. Recent advances in this type of lipase immobilization are reviewed here, in addition to new results regarding the sol-gel entrapment of the lipase from Burkholderia cepacia. It constitutes an excellent heterogeneous biocatalyst in the acylating kinetic resolution of two synthetically and industrially important chiral alcohols, rac-sulcatol and rac-trans-2-methoxycyclohexanol. The observation that the catalyst can be used 10 times in recycling experiments without losing its significant activity or enantioselectivity demonstrates the practical viability of

  13. Theoretical study of the pyrolysis of vanillin as a model of secondary lignin pyrolysis

    NASA Astrophysics Data System (ADS)

    Wang, Meng; Liu, Chao; Xu, Xiaoxiao; Li, Qibin

    2016-06-01

    The unimolecular and bimolecular decomposition reactions in processes of vanillin pyrolysis were theoretically investigated by employing density functional theory (DFT) method at M06-2X/6-31 G+(d,p) level. The result shows that the homolytic cleavage of O-CH3 bond could be the dominant initial step in the pyrolysis of vanillin. The hydrogen abstractions from functional groups of vanillin by the formed radicals play important roles in the formation of main products. Both formyl, hydroxyl and methoxyl group contribute to the formation of CO. Benzene is formed from the hydrogen addition reaction between hydrogen radical and phenol at high temperature.

  14. FTIR gas-phase kinetic study on the reactions of some acrylate esters with OH radicals and Cl atoms.

    PubMed

    Moreno, A; Gallego-Iniesta, M P; Taccone, R; Martín, M P; Cabañas, B; Salgado, M S

    2014-10-01

    Acrylate esters are α,β-unsaturated esters that contain vinyl groups directly attached to the carbonyl carbon. These compounds are widely used in the production of plastics and resins. Atmospheric degradation processes of these compounds are currently not well understood. The kinetics of the gas phase reactions of OH radicals with methyl 3-methylacrylate and methyl 3,3-dimethylacrylate were determined using the relative rate technique in a 50 L Pyrex photoreactor using in situ FTIR spectroscopy at room temperature (298 ± 2 K) and atmospheric pressure (708 ± 8 Torr) with air as the bath gas. Rate coefficients obtained were (in units cm(3) molecule(-1) s(-1)): (3.27 ± 0.33) × 10(-11) and (4.43 ± 0.42) × 10(-11), for CH3CH═CHC(O)OCH3 and (CH3)2CH═CHC(O)OCH3, respectively. The same technique was used to study the gas phase reactions of hexyl acrylate and ethyl hexyl acrylate with OH radicals and Cl atoms. In the experiments with Cl, N2 and air were used as the bath gases. The following rate coefficients were obtained (in cm(3) molecule(-1) s(-1)): k3 (CH2═CHC(O)O(CH2)5CH3 + Cl) = (3.31 ± 0.31) × 10(-10), k4(CH2═CHC(O)OCH2CH(CH2CH3)(CH2)3CH3 + Cl) = (3.46 ± 0.31) × 10(-10), k5(CH2═CHC(O)O(CH2)5CH3 + OH) = (2.28 ± 0.23) × 10(-11), and k6(CH2═CHC(O)OCH2CH(CH2CH3)(CH2)3CH3 + OH) = (2.74 ± 0.26) × 10(-11). The reactivity increased with the number of methyl substituents on the double bond and with the chain length of the alkyl group in -C(O)OR. Estimations of the atmospheric lifetimes clearly indicate that the dominant atmospheric loss process for these compounds is their daytime reaction with the hydroxyl radical. In coastal areas and in some polluted environments, Cl atom-initiated degradation of these compounds can be significant, if not dominant. Maximum Incremental Reactivity (MIR) index and global warming potential (GWP) were also calculated, and it was concluded that these compounds have significant MIR values, but they do

  15. Reactions of alkoxysilanes on metal oxide surfaces: decomposition of tetraethoxysilane on MgO(100) and Al 2O 3(0001)

    NASA Astrophysics Data System (ADS)

    Danner, J. B.; Vohs, J. M.

    1993-12-01

    The thermal decomposition of tetraethoxysilane (TEOS) on MgO(100) and Al 2O 3(0001) surfaces was investigated using temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), and high-resolution electron energy-loss spectroscopy (HREELS). TEOS was found to dissociate on both MgO(100) and Al 2O 3(0001) to form ethoxysilane species, Si(OCH 2CH 3) n, n=2, 3. The ethoxysilanes are stable to a temperature of 600 K at which point they decompose, liberating ethanol, ethylene and ethyl radicals and depositing SiO 2.

  16. The Formation of N- and O-Heterocycles from the Irradiation of Benzene and Naphthalene in H2O/NH3- Containing Ices

    NASA Technical Reports Server (NTRS)

    Sandford, S. A.; Materese, C. K.; Nuevo, M.

    2015-01-01

    Aromatic hydrocarbons are an important class of molecules for both astrochemistry and astrobiology (Fig. 1). Within this class of molecules, polycyclic aromatic hydrocarbons (PAHs) are known to be ubiquitous in many astrophysical environments, and are likely present in interstellar clouds and protostellar disks. In dense clouds, PAHs are expected to condense onto grains as part of mixed molecular ice mantles dominated by small molecules like H2O,CH3OH, NH3, CO, and CO2. These ices are exposed to ionizing radiation in the form of cosmic rays and ambient high-energy X-ray and UV photons.

  17. Synthesis of elusive chloropnictenium ions.

    PubMed

    Hering-Junghans, Christian; Thomas, Max; Villinger, Alexander; Schulz, Axel

    2015-04-27

    This work describes the synthesis and full characterization of elusive chloropnictenium ion salts of the type [(R)Ar*N(SiMe)ECl][A] ((R)Ar* = 2,6-(CHPh2)-4-R-C6H2, R = Me, tBu; E = Sb, Bi; A(-) = GaCl4, Al(OCH(CF3)2)4). In these species the cation is significantly stabilized by weak arene interactions to flanking phenyl groups of the (R)Ar* moiety. In this context the bonding situation has been studied by computational means and the reactivity towards the Lewis base 4-dimethylaminopyridine (dmap) was investigated.

  18. [INFECTION OF BLOOD-SUCKING MOSQUITOES (DIPTERA: CULICIDAE) WITH DIROFILARIAE (SPIRURIDA, ONCHOCERCIDAE) IN THE TULA REGION].

    PubMed

    Bogacheva, A S; Ganushkina, L A; Lopatina, Yu V

    2016-01-01

    Blood-sucking mosquitoes (n = 2277) collected in Tula and its Region in 2013-2014 were examined using a PCR assay for dirofilariae. A total of 12 species from 4 genera (Culiseta, Aedes, Ochlerotatus [foreign character] Culex) out of 18 found mosquito species were infected with Dirofilaria immitis and D. repens. The proportion of the infected mosquitoes was 2.5% (D. immitis, 1.5%; D.repens, 1%). According to preliminary data, the most efficient Dirofilaria vectors, in the Tula Region may be Ae. vexans, Ae. geniculatus, Och. cantans, and Cx. pipiens. PMID:27405207

  19. Process for making propenyl ethers and photopolymerizable compositions containing them

    DOEpatents

    Crivello, J.V.

    1996-01-23

    Propenyl ether monomers of formula A(OCH{double_bond}CHCH{sub 3}){sub n} (V) wherein n is an integer from one to six and A is selected from cyclic ethers, polyether, and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of formula V together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

  20. Propenyl ether monomers for photopolymerization

    DOEpatents

    Crivello, J.V.

    1996-10-22

    Propenyl ether monomers of formula A(OCH{double_bond}CHCH{sub 3}){sub n} wherein n is an integer from one to six and A is selected from cyclic ethers, polyether and alkanes are disclosed. The monomers are readily polymerized in the presence of cationic photoinitiators, when exposed to actinic radiation, to form poly(propenyl ethers) that are useful for coatings, sealants, varnishes and adhesives. Compositions for preparing polymeric coatings comprising the compounds of the above formula together with particular cationic photoinitiators are also disclosed, as are processes for making the monomers from allyl halides and readily available alcohols. The process involves rearranging the resulting allyl ethers to propenyl ethers.

  1. Differentiation of Boc-protected alpha,delta-/delta,alpha- and beta,delta-/delta,beta-hybrid peptide positional isomers by electrospray ionization tandem mass spectrometry.

    PubMed

    Raju, G; Ramesh, V; Srinivas, R; Sharma, G V M; Shoban Babu, B

    2010-06-01

    Two new series of Boc-N-alpha,delta-/delta,alpha- and beta,delta-/delta,beta-hybrid peptides containing repeats of L-Ala-delta(5)-Caa/delta(5)-Caa-L-Ala and beta(3)-Caa-delta(5)-Caa/delta(5)-Caa-beta(3)-Caa (L-Ala = L-alanine, Caa = C-linked carbo amino acid derived from D-xylose) have been differentiated by both positive and negative ion electrospray ionization (ESI) ion trap tandem mass spectrometry (MS/MS). MS(n) spectra of protonated isomeric peptides produce characteristic fragmentation involving the peptide backbone, the Boc-group, and the side chain. The dipeptide positional isomers are differentiated by the collision-induced dissociation (CID) of the protonated peptides. The loss of 2-methylprop-1-ene is more pronounced for Boc-NH-L-Ala-delta-Caa-OCH(3) (1), whereas it is totally absent for its positional isomer Boc-NH-delta-Caa-L-Ala-OCH(3) (7), instead it shows significant loss of t-butanol. On the other hand, second isomeric pair shows significant loss of t-butanol and loss of acetone for Boc-NH-delta-Caa-beta-Caa-OCH(3) (18), whereas these are insignificant for its positional isomer Boc-NH-beta-Caa-delta-Caa-OCH(3) (13). The tetra- and hexapeptide positional isomers also show significant differences in MS(2) and MS(3) CID spectra. It is observed that 'b' ions are abundant when oxazolone structures are formed through five-membered cyclic transition state and cyclization process for larger 'b' ions led to its insignificant abundance. However, b(1)(+) ion is formed in case of delta,alpha-dipeptide that may have a six-membered substituted piperidone ion structure. Furthermore, ESI negative ion MS/MS has also been found to be useful for differentiating these isomeric peptide acids. Thus, the results of MS/MS of pairs of di-, tetra-, and hexapeptide positional isomers provide peptide sequencing information and distinguish the positional isomers.

  2. [INFECTION OF BLOOD-SUCKING MOSQUITOES (DIPTERA: CULICIDAE) WITH DIROFILARIAE (SPIRURIDA, ONCHOCERCIDAE) IN THE TULA REGION].

    PubMed

    Bogacheva, A S; Ganushkina, L A; Lopatina, Yu V

    2016-01-01

    Blood-sucking mosquitoes (n = 2277) collected in Tula and its Region in 2013-2014 were examined using a PCR assay for dirofilariae. A total of 12 species from 4 genera (Culiseta, Aedes, Ochlerotatus [foreign character] Culex) out of 18 found mosquito species were infected with Dirofilaria immitis and D. repens. The proportion of the infected mosquitoes was 2.5% (D. immitis, 1.5%; D.repens, 1%). According to preliminary data, the most efficient Dirofilaria vectors, in the Tula Region may be Ae. vexans, Ae. geniculatus, Och. cantans, and Cx. pipiens.

  3. Reactions of 3-OXETANONE at High Temperatures

    NASA Astrophysics Data System (ADS)

    Wright, Emily; Warner, Brian; Foreman, Hannah; Urness, Kimberly N.; McCunn, Laura R.

    2015-06-01

    The pyrolysis of 3-oxetanone, O(CH2)2CO, has been studied in a resistively heated SiC tubular reactor at 400-1200 °C. Products of pyrolysis were identified via matrix-isolation FTIR spectroscopy and photoionization mass spectrometry in separate experiments. While 3-oxetanone is expected to dissociate into ketene and formaldehyde, these experiments show that ethylene oxide and carbon monoxide are also produced. Methyl radical and ethylene were observed as additional products and are thought to be the result of reactions involving ethylene oxide.

  4. Exposures of preschool children to chlorpyrifos, diazinon, pentachlorophenol, and 2,4-dichlorophenoxyacetic acid over 3 years from 2003 to 2005: A longitudinal model.

    PubMed

    Wilson, Nancy K; Strauss, Warren J; Iroz-Elardo, Nicole; Chuang, Jane C

    2010-09-01

    The impact of the US EPA-required phase-outs starting in 2000-2001 of residential uses of the organophosphate (OP) pesticides chlorpyrifos (CPF) and diazinon (DZN) on preschool children's pesticide exposures was investigated over 2003-2005, in the Raleigh-Durham-Chapel Hill area of North Carolina. Data were collected from 50 homes, each with a child initially of age 3 years (OCh) and a younger child (YCh). Environmental samples (indoor and outdoor air, dust, soil) and child-specific samples (hand surface residue, urine, diet) were collected annually over 24-h periods at each home. Child time-activity diaries and household pesticide use information were also collected. Analytes included CPF and DZN; pentachlorophenol (PCP); 2,4-dichlorophenoxyacetic acid (2,4-D); the CPF metabolite 3,5,6-trichloro-2-pyridinol (TCP); and the DZN metabolite 2-isopropyl-6-methyl-4-pyrimidinol (IMP). Exposures (ng/day) through the inhalation, dietary ingestion, and indirect ingestion were calculated. Aggregate potential doses in ng/kg body weight per day (ng/kg/day) were obtained by summing the potential doses through the three routes of exposure. Geometric mean aggregate potential doses decreased from 2003 to 2005 for both OCh and YCh, with the exception of 2,4-D. Child-specific longitudinal modeling indicated significant declines across time of the potential doses of CPF, DZN, and PCP for both children; declines of IMP for both children, significant only for OCh; a decline of TCP for OCh but an increase of TCP for YCh; and no significant change of 2,4-D for either child. Age-adjusted modeling indicated significant effects of the child's age for all except CPF, and of time for all except PCP and 2,4-D. Within-home variability was small compared with that between homes; variability was smallest for 2,4-D, both within and between homes. The aggregate potential doses of CPF and DZN were well below published reference dose values. These findings show the success of the US EPA restrictions

  5. Artocarpin-galactomannan interaction: characterization of combining site of artocarpin.

    PubMed

    Chowdhury, S; Chatterjee, B P

    1993-01-01

    Artocarpin, a lectin purified from Artocarpus lakoocha seeds, precipitates well several galactomannans having terminal D-Gal-alpha-(1-6)-residues. Quantitative precipitin-inhibition studies using various haptens suggest that the -OCH2-group at C-1 and hydroxyl groups at C-4, and partially at C-6, in the alpha-glycoside of D-galactose configuration are necessary for lectin-sugar interaction. The formation of an artocarpin-fenugreek galactomannan complex was dependent on temperature, pH, ionic strength and the number of hydroxy groups of alditols added to the medium.

  6. Two tri-spin complexes based on gadolinium and nitronyl nitroxide radicals: Structure and ferromagnetic interactions

    SciTech Connect

    Zhou Na; Ma Yue; Wang Chao; Xu Gongfeng; Tang Jinkui; Yan Shiping; Liao Daizheng

    2010-04-15

    Three Radical-Ln(III)-Radical complexes based on nitronyl nitroxide radicals have been synthesized, structurally and magnetically characterized: [Gd(hfac){sub 3}(NITPhOEt){sub 2}] (1) (hfac=hexafluoroacetylacetonate, and NITPhOEt=4'-ethoxy-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), [Gd(hfac){sub 3}(NITPhOCH{sub 2}Ph){sub 2}] (2) (NITPhOCH{sub 2}Ph=4'-benzyloxy-phenyl-4,4,5, 5-tetramethylimidazoline-1-oxyl-3-oxide) and [Lu(hfac){sub 3}(NITPhOCH{sub 2}Ph){sub 2}] (3). The X-ray crystal structure analyses show that the structures of the three compounds are similar and all consist of the isolated molecules, in which central ions Gd{sup III} or Lu{sup III} are coordinated by six oxygen atoms from three hfac and two oxygen atoms from nitronyl radicals. The magnetic studies show that in both of the two Gd{sup III} complexes, there are ferromagnetic Gd{sup III}-Rad interactions and antiferro-magnetic Rad-Rad interactions in the molecules (with J{sub Rad-Gd}=0.27 cm{sup -1}, j{sub Rad-Rad}=-2.97 cm{sup -1} for 1: and J{sub Rad-Gd}=0.62 cm{sup -1}, j{sub Rad-Rad}=-7.01 cm{sup -1} for 2). An analogous complex of [Lu(hfac){sub 3} (NITPhOCH{sub 2}Ph){sub 2}] (3) containing diamagnetic Lu{sup III} ions has also been introduced for further demonstrating the nature of magnetic coupling between radicals. - Graphical abstract: Two tri-spin complexes based on gadolinium-radical have been synthesized and characterized, the magnetic studies show that in the two complexes the Gd-radical interaction is ferromagnetic and the radical-radical interaction is antiferromagnetic. An analogous complex containing the diamagnetic Lu{sup III} ions has also been synthesized to further demonstrate the nature of the magnetic coupling between radicals.

  7. New secoiridoids from the fruits of Ligustrum lucidum Ait with triglyceride accumulation inhibitory effects.

    PubMed

    Zhang, Yi; Liu, Lili; Gao, Jing; Wu, Chunhua; Han, Lifeng; Liu, Erwei; Shi, Pingping; Gao, Xiumei; Wang, Tao

    2013-12-01

    Five new secoiridoids, nuzhenal C (1), 6'-O-trans-cinnamoyl iso-8-epikingisidic acid (2), ligulucidumosides A (3), B (4), and C (5), were obtained from the fruits of Ligustrum lucidum Ait. Their structures were elucidated by chemical and spectroscopic methods (UV, IR, HRESI-TOF-MS, 1D and 2D NMR). Among them, compound 3 is the first 1-OCH3 substituent secoiridoid obtained from plant kingdom. Furthermore, activity screening results showed that all of the isolates had triglyceride accumulation inhibitory effects in HepG2 cells. PMID:24001714

  8. Gas-phase reactions of [VO2(OH)2]- and [V2O5(OH)]- with methanol: experiment and theory.

    PubMed

    Harris, Benjamin L; Waters, Tom; Khairallah, George N; O'Hair, Richard A J

    2013-02-14

    The gas-phase reactivity of the vanadium hydroxides [VO(2)(OH)(2)](-) and [V(2)O(5)(OH)](-) toward methanol was examined using a combination of ion-molecule reactions (IMRs) and collision-induced dissociation (CID) in a quadrupole ion trap mass spectrometer. Isotope-labeling experiments with CD(3)OH, (13)CH(3)OH, and CH(3)(18)OH were used to confirm the stoichiometry of ions and the observed sequence of reactions. The experimental data were interpreted with the aid of density functional theory calculations, carried out at the B3LYP/SDD6-311++G** level of theory. While [VO(2)(OH)(2)](-) is unreactive, [V(2)O(5)(OH)](-) undergoes a metathesis reaction to yield [V(2)O(5)(OCH(3))](-). The DFT calculations reveal that the metathesis reaction of methanol with [VO(2)(OH)(2)](-) suffers from a barrier of +0.52 eV (relative to separated reactants) but that the reaction of [V(2)O(5)(OH)](-) with methanol readily proceeds via addition/elimination reactions with both transition states being below the energy of the separated reactants. CID of [V(2)O(5)(OCH(3))](-) (m/z 213) yields three ions arising from activation of the methoxo ligand: [V(2), O(6), C, H](-) (m/z 211); [V(2), O(5), H](-) (m/z 183); and [V(2), O(4), H](-) (m/z 167). Additional experiments and DFT calculations suggest that these ions arise from losses of H(2), formaldehyde and the sequential losses of H(2) and CO(2), respectively. The use of an (18)O-labeled methoxo ligand in [V(2)O(5)((18)OCH(3))](-) (m/z 215) showed the competing losses of H(2)C(16)O and H(2)C(18)O and [H(2) and C(16)O(18)O] and [H(2) and C(16)O(2)], highlighting that (16)O/(18)O exchange between the methoxo ligand and the vanadium oxide occurs prior to the subsequent fragmentation of the ligand. DFT calculations reveal that a key step involves hydrogen atom transfer from the methoxo ligand to the oxo ligand of the same vanadium center, producing the intermediate [V(2)O(4)(OH)(OCH(2))](-) containing a ketyl radical ligand and a hydroxo ligand

  9. Insight into selected reactions in low-temperature dimethyl ether combustion from Born-Oppenheimer molecular dynamics.

    PubMed

    Andersen, Amity; Carter, Emily A

    2006-02-01

    Dimethyl ether is under consideration as an alternative diesel fuel. Its combustion chemistry is as yet ill-characterized. Here we use Born-Oppenheimer molecular dynamics (BOMD) based on DFT-B3LYP forces to investigate the short-time dynamics of selected features of the low-temperature dimethyl ether (DME) oxidation potential energy surface. Along the chain propagation pathway, we run BOMD simulations from the transition state involving the decomposition of (*)CH(2)OCH(2)OOH to two CH(2)=O and an (*)OH radical. We predict that formaldehyde C-O stretch overtones are excited, consistent with laser photolysis experiments. We also predict that O-H overtones are excited for the (*)OH formed from (*)CH(2)OCH(2)OOH dissociation. We also investigate short-time dynamics involved in chain branching. First, we examine the isomerization transition state of (*)OOCH(2)OCH(2)OOH --> HOOCH(2)OCHOOH. The latter species is predicted to be a short-lived metastable radical that decomposes within 500 fs to hydroperoxymethyl formate (HPMF; HOOCH(2)OC(=O)H) and the first (*)OH of chain branching. The dissociation of HOOCH(2)OCHOOH exhibits non-RRKM behavior in its lifetime profile, which may be due to conformational constraints or slow intramolecular vibrational energy transfer (IVR) from the nascent H-O bond to the opposite end of the radical, where O-O scission occurs to form HPMF and (*)OH. In a few trajectories, we see HOOCH(2)OCHOOH recross back to (*)OOCH(2)OCH(2)OOH because the isomerization is endothermic, with only an 8 kcal/mol barrier to recrossing. Therefore, some inhibition of chain-branching may be due to recrossing. Second, trajectories run from the transition state leading to the direct decomposition of HPMF (an important source of the second (*)OH radical in chain branching) to HCO, (*)OH, and HC(=O)OH show that these products can recombine to form many other possible products. These products include CH(2)OO + HC(=O)OH, H(2)O + CO + HC(=O)OH, HC(=O)OH + HC(=O)OH, and HC

  10. Non-strinking siloxane polymers

    DOEpatents

    Loy, Douglas A.; Rahimian, Kamyar

    2001-01-01

    Cross-linked polymers formed by ring-opening polymerization of a precursor monomer of the general formula R[CH.sub.2 CH(Si(CH.sub.3).sub.2).sub.2 O].sub.2, where R is a phenyl group or an alkyl group having at least two carbon atoms. A cross-linked polymer is synthesized by mixing the monomer with a co-monomer of the general formula CH.sub.2 CHR.sup.2 (SiMe.sub.2).sub.2 O in the presence of an anionic base to form a cross-linked polymer of recurring units of the general formula R(Me.sub.2 SiOCH.sub.2 CHSiMe.sub.2).sub.2 [CH.sub.2 CHR.sup.2 (SiMe.sub.2).sub.2 O].sub.n, where R.sup.2 is hydrogen, phenyl, ethyl, propyl or butyl. If the precursor monomer is a liquid, the polymer can be directly synthesized in the presence of an anionic base to a cross-linked polymer containing recurring units of the general formula R(Me.sub.2 SiOCH.sub.2 CHSiMe.sub.2).sub.2. The polymers have approximately less than 1% porosity and are thermally stable at temperatures up to approximately 500.degree. C. The conversion to the cross-linked polymer occurs by ring opening polymerization and results in shrinkage of less than approximately 5% by volume.

  11. A noticeable phenomenon: thiol terminal PEG enhances the immunogenicity of PEGylated emulsions injected intravenously or subcutaneously into rats.

    PubMed

    Wang, Chunling; Cheng, Xiaobo; Sui, Yue; Luo, Xiang; Jiang, Gongping; Wang, Yu; Huang, Zhenjun; She, Zhennan; Deng, Yihui

    2013-11-01

    Repeated intravenous injection of long-circulating methoxy-polyethylene glycol (PEG)-liposomes alters the pharmacokinetics and biodistribution of the second administration, regarded as the "accelerated blood clearance (ABC) phenomenon." Nevertheless, the effect of terminal groups of distearoylphosphatidylethanolamine-polyethylene glycol (DSPE-PEG) on the induction of the ABC phenomenon had not been reported previously. In this study, rats were injected intravenously or subcutaneously with PEG coated emulsions (DE) which were prepared using PEG terminated with either the methoxyl (OCH3), hydroxyl (OH), amino (NH2), carboxyl (COOH), or thiol (SH) group. DE-OCH3 demonstrated the longest prolonged half-life in vivo after a single intravenous injection, followed by DE-SH and DE-COOH. In contrast, DE-OH was rapidly removed from the blood circulation, as was DE-NH2. Moreover, we observed a strong positive relationship between the circulation time of initially injected PEGylated emulsions and the extent to which the ABC phenomenon was induced, but a exception of DE-SH increasing the ABC effect. Furthermore, the present study suggested that thiols might stimulate the proliferation and differentiation of B cells to induce the fastest clearance of the second intravenous administration by inducing the synthesis of the cell membrane and cytosolic proteins or reacting with follicular dendritic cells. The results strongly suggested that thiol groups played a stimulatory role in the immune response and provided a considerable implication for multiple drug therapy of thiol groups. PMID:24129310

  12. Reactive Capture of Gold Nanoparticles by Strongly Physisorbed Monolayers on Graphite

    SciTech Connect

    Wei, Xiaoliang; Tong, Wenjun; Fidler, Vlastimil; Zimmt, Matthew B.

    2012-12-01

    Anthracene Diels Alder adducts (DAa) bearing two long side chains (H-(CH2)22O(CH2)6OCH2-) at the 1- and 5-positions form self-assembled monolayers (SAMs) at the phenyloctane - highly oriented pyrolytic graphite (HOPG) interface. The long DAa side chains promote strong physisorption of the monolayer to HOPG and maintain the monolayer morphology upon rinsing or incubation in ethanol and air-drying of the substrate. Incorporating a carboxylic acid group on the DAa core enables capture of 1 - 4 nm diameter gold nanoparticles (AuNP) provided (i) the monolayer containing DAa-carboxylic acids is treated with Cu2+ ions and (ii) the organic coating on the AuNP contains carboxylic acids (11-mercaptoundecanoic acid, MUA-AuNP). AuNP capture by the monolayer proceeds with formation of Cu2+ - carboxylate coordination complexes. The captured AuNP appear as mono- and multi-layered clusters at high coverage on HOPG. The surface density of the captured AuNPs can be adjusted from AuNP multi-layers to isolated AuNPs by varying incubation times, MUA-AuNP concentration, the number density of carboxylic acids in the monolayer, the number of MUA per AuNP, and the post-incubation treatments.

  13. Insight into the evolution, redox, and metal binding properties of dissolved organic matter from municipal solid wastes using two-dimensional correlation spectroscopy.

    PubMed

    He, Xiao-Song; Xi, Bei-Dou; Zhang, Zong-Yong; Gao, Ru-Tai; Tan, Wen-Bing; Cui, Dong-Yu

    2014-12-01

    Two-dimensional correlation spectroscopy was employed to investigate the evolution, redox, and metal binding properties of dissolved organic matter (DOM) from municipal solid wastes (MSWs) during composting. The results showed that the DOM was degraded during composting in the order of aliphatic substances > proteinaceous compounds > cellulose, hemicellulose and lignin, while humic substances transformed during the process in the order of fulvic-like matter > humic-like substances > protein-like matter. The fulvic- and humic-like substances originated from lignin and polysaccharide-like substances with the function groups of CH3, CCH2, CCH, OCH3, OCH, O--C--O, aromatic C, and COO, while the protein-like matter was derived from aliphatic and proteinaceous compounds with the functional groups of CCH3 and N--C==O. The aromatic C and COO were responsible for the oxidation capacity of the MSW-derived DOM, while the O--C--O and COO accounted for the Cu and Zn binding capacity of the DOM.

  14. Conformational, electronic and antioxidant properties of lucidone, linderone and methyllinderone: DFT, QTAIM and NBO studies

    NASA Astrophysics Data System (ADS)

    Kabanda, Mwadham M.; Tan Tran, Van; Seema, Kamogelo M.; Serobatse, Kemoabetswe R. N.; Tsiepe, Tshepiso J.; Tran, Quoc Tri; Ebenso, Eno E.

    2015-04-01

    Theoretical studies on lucidone, linderone and methyllinderone were performed to investigate factors that contribute to structural stability and to elucidate the antioxidant properties and mechanisms. The study was performed in different media utilising the density functional theory with different functionals and the 6-311+ G(d,p) basis set. The antioxidant activity has been considered through the electron transfer and metal chelation mechanisms. The results show that the stability of the tautomers and conformers is due to the presence of several intramolecular hydrogen bonds. The ionisation potential values suggest that the antiradical activity increases with the increase in the number of OCH3 groups substituted on the cyclopentene-1,3-dione ring. In vacuo, the spin density of the Fe(II) cation upon ligand coordination decreases to 3.0-3.5, whereas the ligand spin density approaches 1, indicating that it is oxidised to a radical cation. The metal ion affinity (MIA) is influenced by the position and number of OCH3 substituted on the acylcyclopentene-1,3-dione ring. A very favourable MIA, in vacuo, is obtained when Fe(II) is chelated between the sp2 O and sp3 O atoms. An estimation of MIA in an aqueous solution shows a remarkable decrease with respect to the results in vacuo.

  15. Synthesis and biological evaluation of pyrazolylthiazole carboxylic acids as potent anti-inflammatory-antimicrobial agents.

    PubMed

    Khloya, Poonam; Kumar, Satish; Kaushik, Pawan; Surain, Parveen; Kaushik, Dhirender; Sharma, Pawan K

    2015-03-15

    Current Letter presents design, synthesis and biological evaluation of a novel series of pyrazolylthiazole carboxylates 1a-1p and corresponding acid derivatives 2a-2p. All 32 novel compounds were tested for their in vivo anti-inflammatory activity by carrageenan-induced rat paw edema method as well as for in vitro antimicrobial activity. All the tested compounds exhibited excellent AI activity profile. Three compounds 1p (R=Cl, R(1)=Cl), 2c (R=H, R(1)=F) and 2n (R=Cl, R(1)=OCH3) were identified as potent anti-inflammatory agents exhibiting edema inhibition of 93.06-89.59% which is comparable to the reference drug indomethacin (91.32%) after 3h of carrageenan injection while most of the other compounds displayed inhibition ⩾80%. In addition, pyrazolylthiazole carboxylic acids (2a-2p) also showed good antimicrobial profile. Compound 2h (R=OCH3, R(1)=Cl) showed excellent antimicrobial activity (MIC 6.25μg/mL) against both Gram positive bacteria comparable with the reference drug ciprofloxacin (MIC 6.25μg/mL).

  16. Mechanistic study of atomic layer deposition of Al{sub x}Si{sub y}O thin film via in-situ FTIR spectroscopy

    SciTech Connect

    Cho, Jea; Kim, Taeseung; Seegmiller, Trevor; Chang, Jane P.

    2015-09-15

    A study of surface reaction mechanism on atomic layer deposition (ALD) of aluminum silicate (Al{sub x}Si{sub y}O) was conducted with trimethylaluminum (TMA) and tetraethoxysilane (TEOS) as precursors and H{sub 2}O as the oxidant. In-situ Fourier transform infrared spectroscopy (FTIR) was utilized to elucidate the underlying surface mechanism that enables the deposition of Al{sub x}Si{sub y}O by ALD. In-situ FTIR study revealed that ineffective hydroxylation of the surface ethoxy (–OCH{sub 2}CH{sub 3}) groups prohibits ALD of SiO{sub 2} by TEOS/H{sub 2}O. In contrast, effective desorption of the surface ethoxy group was observed in TEOS/H{sub 2}O/TMA/H{sub 2}O chemistry. The presence of Al-OH* group in vicinity of partially hydroxylated ethoxy (–OCH{sub 2}CH{sub 3}) group was found to propagate disproportionation reaction, which results in ALD of Al{sub x}Si{sub y}O. The maximum thickness from incorporation of SiO{sub x} from alternating exposures of TEOS/H{sub 2}O chemistry in Al{sub x}Si{sub y}O was found to be ∼2 Å, confirmed by high resolution transmission electron microscopy measurements.

  17. Catalyst Structure-Performance Relationship Identified by High-Throughput Operando Method: New Insight for Silica-Supported Vanadium Oxide for Methanol Oxidation

    SciTech Connect

    Li, Guosheng; Hu, Dehong; Xia, Guanguang; Zhang, Z Conrad

    2010-02-01

    A prototype high throughput operando reactor, that integrates FT-IR imaging for rapid reaction product analysis and parallel Raman imaging for catalyst characterization, has been designed to accelerate catalyst discovery and, concurrently, fundamental research toward reliable correlations between catalyst active sites and catalyst performance for at-line real catalytic conditions. This reactor, consisting of six parallel reaction channels, is demonstrated for methanol oxidation using silica supported vanadium oxide catalysts at various reaction conditions. The results of semi-quantitative analysis of a large array of operando Raman scattering bands, specifically for C-H bonds in Si-OCH3 and V-OCH3 surface intermediates, obtained simultaneously on multiple catalyst surfaces with a time resolution of 60s for each set at different temperatures, reveal for the first time methanol activation at surface vanadium oxide cluster edge on silica support at lower reaction temperatures, <175°C. This activation phenomenon is not observed at a higher reaction temperature, 225°C.

  18. Mechanistic understanding of hydrogenation of acetaldehyde on Au(111): A DFT investigation

    NASA Astrophysics Data System (ADS)

    Meng, Qingsen; Shen, Yongli; Xu, Jing; Ma, Xinbin; Gong, Jinlong

    2012-11-01

    This paper describes the reaction pathways for hydrogenation of acetaldehyde on atomic hydrogen pre-adsorbed Au(111) employing density functional theory (DFT) calculations. All the surface species involved in the reaction scheme have low diffusion barriers, suggesting that the rearrangement and movement of these species on the surface are facile under reaction condition. The hydroxyethyl is proposed to be the intermediate for the hydrogenation of acetaldehyde, and the activation energy for its formation is 0.37 eV. Additionally, the coupling reaction of hydroxyethyl and acetaldehyde - resulting in the formation of the ethylidene ethylene glycol (CH3C*HOCH(CH3)OH) species - also readily occurs at the reaction condition. Two-dimensional (2-D) polyacetaldehyde ((CH3CHO)2) can be easily hydrogenated to ethylidene ethylene glycol or ethoxy hemiacetal (CH3CH2OCH(CH3)O*); the latter can be converted to ethanol and acetaldehyde via further hydrogenation. As the hydrogenation products of ethylidene ethylene glycol and ethoxy hemiacetal, ethoxyethanol (CH3CH2OCH(CH3)OH) can be deeply hydrogenated to hydroxyethyl and ethanol. Our calculations also suggest that the formation of an ethoxyl intermediate is not likely, which agrees with the experimental observation that no deuterated acetaldehydes have been detected in isotopic measurements.

  19. Rational discovery and development of a mitochondria-targeted antioxidant based on cinnamic acid scaffold.

    PubMed

    Teixeira, José; Soares, Pedro; Benfeito, Sofia; Gaspar, Alexandra; Garrido, Jorge; Murphy, Michael P; Borges, Fernanda

    2012-05-01

    A novel mitochondria-targeted antioxidant (TPP-OH) was synthesized by attaching the natural hydrophilic antioxidant caffeic acid to an aliphatic lipophilic carbon chain containing a triphenylphosphonium (TPP) cation. This compound has similar antioxidant activity to caffeic acid as demonstrated by measurement of DPPH/ABTS radical quenching and redox potentials, but is significantly more hydrophobic than its precursor as indicated by the relative partition coefficients. The antioxidant activity of both compounds was intrinsic related to the ortho-catechol system, as the methoxylation of the phenolic functions, namely in TPP-OCH(3) and dimethoxycinnamic acid, gave compounds with negligible antioxidant action. The incorporation of the lipophilic TPP cation to form TTP-OH and TPP-OCH(3) allowed the cinnamic derivatives to accumulate within mitochondria in a process driven by the membrane potential. However, only TPP-OH was an effective antioxidant: TPP-OH protected cells against H(2)O(2) and linoleic acid hydroperoxide-induced oxidative stress. As mitochondrial oxidative damage is associated with a number of clinical disorders, TPP-OH may be a useful lead that could be added to the family of mitochondria-targeted antioxidants that can decrease mitochondrial oxidative damage.

  20. Ion-molecule reactions involving HCO+ and N2H+: Isotopologue equilibria from new theoretical calculations and consequences for interstellar isotope fractionation

    NASA Astrophysics Data System (ADS)

    Mladenović, M.; Roueff, E.

    2014-06-01

    Aims: We revisit with new augmented accuracy the theoretical dynamics of basic isotope exchange reactions involved in the 12C/13C, 16O/18O, and 14N/15N balance because these reactions have already been studied experimentally in great detail. Methods: Electronic structure methods were employed to explore potential energy surfaces, full-dimensional rovibrational calculations to compute rovibrational energy levels that are numerically exact, and chemical network models to estimate the abundance ratios under interstellar conditions. Results: New exothermicities, derived for HCO+ reacting with CO, provide rate coefficients markedly different from previous theoretical values in particular at low temperatures, resulting in new abundance ratios relevant for carbon chemistry networks. In concrete terms, we obtain a reduction in the abundance of H12C18O+ and an increase in the abundance of H13C16O+ and D13C16O+. In all studied cases, the reaction of the ion with a neutral polarizable molecule proceeds through the intermediate proton-bound complex found to be very stable. For the complexes OCH+··· CO, OCH+··· OC, COHOC+, N2··· HCO+, N2H+··· OC, and N2HN2+, we also calculated vibrational frequencies and dissociation energies. Conclusions: The linear proton-bound complexes possess sizeable dipole moments, which may facilitate their detection.

  1. Competing Noncovalent Host-guest Interactions and H/D Exchange: Reactions of Benzyloxycarbonyl-Proline Glycine Dipeptide Variants with ND3

    NASA Astrophysics Data System (ADS)

    Miladi, Mahsan; Olaitan, Abayomi D.; Zekavat, Behrooz; Solouki, Touradj

    2015-11-01

    A combination of density functional theory calculations, hydrogen/deuterium exchange (HDX) reactions, ion mobility-mass spectrometry, and isotope labeling tandem mass spectrometry was used to study gas-phase "host-guest" type interactions of a benzyloxycarbonyl (Z)-capped proline (P) glycine (G) model dipeptide (i.e., Z-PG) and its various structural analogues with ND3. It is shown that in a solvent-free environment, structural differences between protonated and alkali metal ion (Na+, K+, or Cs+)-complexed species of Z-PG affect ND3 adduct formation. Specifically, [Z-PG + H]+ and [Z-PG-OCH3 + H]+ formed gas-phase ND3 adducts ([Z-PG (or Z-PG-OCH3) + H + ND3]+) but no ND3 adducts were observed for [Z-PG + alkali metal]+ or [Z-PG + H - CO2]+. Experimentally measured and theoretically calculated collision cross sections (CCSs) of protonated and alkali metal ion-complexed Z-PG species showed similar trends that agreed with the observed structural differences from molecular modeling results. Moreover, results from theoretical ND3 affinity calculations were consistent with experimental HDX observations, indicating a more stable ND3 adduct for [Z-PG + H]+ compared to [Z-PG + alkali metal]+ species. Molecular modeling and experimental MS results for [Z-PG + H]+ and [Z-PG + alkali metal]+ suggest that optimized cation-π and hydrogen bonding interactions of carbonyl groups in final products are important for ND3 adduct formation.

  2. Dechlorination of hazardous wastes Ca/NH{sub 3}, Na/NH{sub 3} and borohydride reductions and by thermolysis over solid bases

    SciTech Connect

    Pittman, C.U. Jr.

    1996-10-01

    The dechlorination of PCBs, pentachlorophenol, CAHs, and pesticides has been carried out at 35{degrees}C by Ca/NH{sub 3} or Na/NH{sub 3} and at 68{degrees}C by NaBH{sub 2}(OCH{sub 2}CH{sub 2}OCH{sub 3}){sub 2}/NiX{sub 2} salts in THF. Remarkably, PCB-contaminated soils (clay, sandy loam) are remediated within one min at 35{degrees}C (99.9+% PCB destruction) by solvated electrons present in soil/Ca/NH{sub 3} slurries. Wet soils (>25% H{sub 2}O) are decontaminated using Ca stoichiometries far lower than the H{sub 2}O present. Alternatively, PCBs, for example, can be dechlorinated to polyhydroxylatedbiphenols by heating at 250-400{degrees}C over solid CaO/Ca(OH){sub 2}, MgO/Mg(OH){sub 2}, BaO/Ba(OH){sub 2}, KOH or Na{sub 2}CO{sub 3}. The benzyne mechanism was implicated at 375{degrees}C. More highly chlorinated congeners are destroyed more rapidly while the 2,2{prime}-dichloro- and 2-chloro-congeners are most resistant.

  3. Amphiphilic ferrocenylated alkylpyridinium: the formation of micelles and hydrogels and their disaggregation induced by an external stimulus.

    PubMed

    Suzaki, Yuji; Endo, Hirotaka; Kojima, Takahiro; Osakada, Kohtaro

    2013-12-01

    Ferrocene-containing amphiphiles [py-N-(CH2)nOCH2Fc]Cl (n = 6 (1a), 8 (1b), 10 (1c); py = C5H5N, Fc = Fe(C5H4)(C5H5)) were synthesized. The absorption spectra of 1a-1c in the presence of a small amount of dye (Nile red and pyrene) in aqueous media suggested the formation of micelles which encapsulated the dye molecules. Two critical micelle concentrations were observed at 1.1 mM and 2.3 mM at 20 °C. Compounds 1a and 1c showed a single CMC for each, while the formation of two kinds of micelles, the spherical and rod-like ones, depended on the concentrations. The addition of an oxidant, NaOCl, to the aqueous solution of the micelles of 1b turned ferrocene to ferrocenium and caused the disaggregation of the micelles. The addition of α-cyclodextrin (α-CD) to 2b caused the disaggregation of the micelle and the formation of water-soluble [2]- and [3]pseudorotaxane [{py-N-(CH2)8OCH2Fc}(α-CD)m]Cl (1b(α-CD)m) (m = 1, 2), while mixing 1c and α-CD in water formed the rotaxane gel. The addition of NaOCl to the hydrogel of 1c and α-CD changed the gel to sol. PMID:24141739

  4. Reaction of singlet-excited 2,3-diazabicyclo[2.2.2]oct-2-ene and tert-butoxyl radicals with aryl-substituted benzofuranones.

    PubMed

    Lundgren, Cecilia Vannesjö; Koner, Apurba L; Tinkl, Michael; Pischel, Uwe; Nau, Werner M

    2006-03-01

    5,7-Di-tert-butyl-3-aryl-3H-benzofuran-2-ones are lactones with potential antioxidant activity, owing to their abstractable benzylic C-H hydrogens. The fluorescence quenching of the azoalkane 2,3-diazabicyclo[2.2.2]oct-2-ene (DBO), an established probe for the hydrogen-donor propensity of chain-breaking antioxidants, was investigated for 16 aryl-substituted benzofuranone derivatives [m,m-(CF3)2, p-CN, m-CN, p-CF3, p-COOCH3, m-CF3, p-Cl, p-F, H, m-CH3, p-CH3, m,p-(CH3)2, p-OCH3, o-CH3, o-CF3, o,m-(CH3)2]. Analysis of the rate data in terms of a linear free energy relationship yielded a reaction constant of rho = +0.35. This implies that n,pi*-excited DBO acts as nucleophilic species. In contrast, hydrogen abstraction of tert-butoxyl radicals from the benzofuranones was accelerated by electron-donating substituents (rho = -0.23), in conformity with the electrophilic character of oxygen-centered alkoxyl radicals. Possible implications for the optimization of the hydrogen-donor propensity of antioxidants through structural variation are discussed.

  5. Forces on the Middle EC Module Connections Resulting From Assembly Sequence A

    SciTech Connect

    Wands, R.; /Fermilab

    1986-09-23

    The ANSYS superelement model representing the sequential assembly of the ec modules has been used to calculate the maximum forces experienced at any interface between middle modules during assembly. The assembly sequence used was devised by GTM and is referred to as Sequence A. Fig. 1 shows the assembled model and support. One-half symmetry is assumed. The superelement model supported the OCH modules at theta = 56.25 in such a way that the support was allowed to translate freely in the horizontal direction, and rotate freely about the longitudinal (beam) axis. This produces 'worst case' module connecting forces, and is justified given the importance of these connections. The middle modules were supported within the OCH arch only through theta = 56.25. Each middle module interface contained six connection points in the fmite element model through which the forces were transmitted between modules. In presenting the results here, the forces at the three connection locations at the inner radius of each interface were summed, and the largest value found. This was also done for the outer radius. In applying these results to the design of the actual connections, the forces presented here should be divided by the actual number of connection points used.

  6. T helper type 2-polarized invariant natural killer T cells reduce disease severity in acute intra-abdominal sepsis

    PubMed Central

    Anantha, R V; Mazzuca, D M; Xu, S X; Porcelli, S A; Fraser, D D; Martin, C M; Welch, I; Mele, T; Haeryfar, S M M; McCormick, J K

    2014-01-01

    Sepsis is characterized by a severe systemic inflammatory response to infection that is associated with high morbidity and mortality despite optimal care. Invariant natural killer T (iNK T) cells are potent regulatory lymphocytes that can produce pro- and/or anti-inflammatory cytokines, thus shaping the course and nature of immune responses; however, little is known about their role in sepsis. We demonstrate here that patients with sepsis/severe sepsis have significantly elevated proportions of iNK T cells in their peripheral blood (as a percentage of their circulating T cells) compared to non-septic patients. We therefore investigated the role of iNK T cells in a mouse model of intra-abdominal sepsis (IAS). Our data show that iNK T cells are pathogenic in IAS, and that T helper type 2 (Th2) polarization of iNK T cells using the synthetic glycolipid OCH significantly reduces mortality from IAS. This reduction in mortality is associated with the systemic elevation of the anti-inflammatory cytokine interleukin (IL)-13 and reduction of several proinflammatory cytokines within the spleen, notably interleukin (IL)-17. Finally, we show that treatment of sepsis with OCH in mice is accompanied by significantly reduced apoptosis of splenic T and B lymphocytes and macrophages, but not natural killer cells. We propose that modulation of iNK T cell responses towards a Th2 phenotype may be an effective therapeutic strategy in early sepsis. PMID:24965554

  7. 2-Methoxyphenyl isocyanate and 2-Methoxyphenyl isothiocyanate: conformers, vibration structure and multiplet Fermi resonance.

    PubMed

    Yenagi, Jayashree; Nandurkar, Anita R; Tonannavar, J

    2012-06-01

    IR and Raman spectral measurements in the region 3500-400/50 cm(-1) have been made for the liquid samples of 2-Methoxyphenyl isocyanate and 2-Methoxyphenyl isothiocyanate. A complete assignment of the measured bands has been proposed as aided by conformational and vibration analyses at B3LYP/6-311++G** level of calculations. Three conformers for 2-Methoxyphenyl isocyanate and two for 2-Methoxyphenyl isothiocyanate have been determined. The tilt of the isocyanate (NCO) and isothiocyanate (NCS) moieties with respect to phenyl ring are in broad agreement with their parents. Stretching mode frequencies of methyl group (-OCH(3)) in 2-Methoxyphenyl isocyanate have been lowered in the 2900-2800 cm(-1); deformation asymmetric modes are IR strong and symmetric one Raman strong. In 2-Methoxyphenyl isothiocyanate, a similar pattern is true for stretching modes but deformation asymmetric modes are IR strong and symmetric mode has not been observed. Multiplet absorption band system near 2200 cm(-1) in 2-Methoxyphenyl isocyanate has been interpreted to be caused by Fermi resonance. A similar pattern in absorption near 2100 cm(-1) in 2-Methoxyphenyl isothiocyanate but more complex Raman band pattern has also been explained through Fermi resonance from heuristic stand-point. Many Raman modes in 1300-1100 cm(-1) are intensified apparently owing to isothiocyanate than isocyanate moiety. Phenyl ring breathing mode is shifted to 1040 cm(-1) as strong Raman; the symmetric stretching mode of O-CH(3) near 1023 cm(-1) as strong absorption.

  8. Leishmania amazonensis: heme stimulates (Na(+)+K(+))ATPase activity via phosphatidylinositol-specific phospholipase C/protein kinase C-like (PI-PLC/PKC) signaling pathways.

    PubMed

    Almeida-Amaral, Elmo Eduardo; Cardoso, Viviane Carrozino; Francioli, Fernanda Gomes; Meyer-Fernandes, José Roberto

    2010-04-01

    In the present paper we studied the involvement of the phosphatidylinositol-specific PLC (PI-PLC)/protein kinase C (PKC) pathway in (Na(+)+K(+))ATPase stimulation by heme in Leishmania amazonensis promastigotes. Heme stimulated the PKC-like activity with a concentration of 50nM. Interestingly, the maximal stimulation of the PKC-like activity promoted by phorbol ester was of the same magnitude promoted by heme. However, the stimulatory effect of heme is completely abolished by ET-18-OCH(3) and U73122, specific inhibitors of PI-PLC. (Na(+)+K(+))ATPase activity is increased in the presence of increased concentrations of heme, being maximally affected at 50nM. This effect was completely reversed by 10nM calphostin C, an inhibitor of PKC. Thus, the effect of 50nM heme on (Na(+)+K(+))ATPase activity is completely abolished by ET-18-OCH(3) and U73122. Taken together, these results demonstrate that the heme receptor mediates the stimulatory effect of heme on the (Na(+)+K(+))ATPase activity through a PI-PLC/PKC signaling pathway. PMID:20045694

  9. The MAPKKK Ste11 regulates vegetative growth through a kinase cascade of shared signaling components.

    PubMed

    Lee, B N; Elion, E A

    1999-10-26

    In haploid Saccharomyces cerevisiae, the mating and invasive growth (IG) pathways use the same mitogen-activated protein kinase kinase kinase kinase (MAPKKKK, Ste20), MAPKKK (Ste11), MAPKK (Ste7), and transcription factor (Ste12) to promote either G(1) arrest and fusion or foraging in response to distinct stimuli. This exquisite specificity is the result of pathway-specific receptors, G proteins, scaffold protein, and MAPKs. It is currently not thought that the shared signaling components function under the basal conditions of vegetative growth. We tested this hypothesis by searching for mutations that cause lethality when the STE11 gene is deleted. Strikingly, we found that Ste11, together with Ste20, Ste7, Ste12, and the IG MAPK Kss1, functions in a third pathway that promotes vegetative growth and is essential in an och1 mutant that does not synthesize mannoproteins. We term this pathway the STE vegetative growth (SVG) pathway. The SVG pathway functions, in part, to promote cell wall integrity in parallel with the protein kinase C pathway. During vegetative growth, the SVG pathway is inhibited by the mating MAPK Fus3. By contrast, the SVG pathway is constitutively activated in an och1 mutant, suggesting that it senses intracellular changes arising from the loss of mannoproteins. We predict that general proliferative functions may also exist for other MAPK cascades thought only to perform specialized functions. PMID:10535982

  10. Surface chemistry of boron-doped SiO{sub 2} CVD: Enhanced uptake of tetraethyl orthosilicate by hydroxyl groups bonded to boron

    SciTech Connect

    Bartram, M.E.; Moffat, H.K.

    1993-12-31

    Insight into how dopants can enhance deposition rates has been obtained by comparing reactivities of tetraethyl orthosilicate (TEOS, Si(OCH{sub 2}CH{sub 3}){sub 4}) with silanol and boranol groups on SiO{sub 2}. This comparison is relevant for boron-doped SiO{sub 2} film growth from TEOS and trimethyl borate (TMB, B(OCH{sub 3}){sub 3}) sources since boranols and silanols are expected to be present on surface during the (CVD). A silica substrate having coadsorbed deuterated silanols (SIOD) and boranols (BOD) was reacted with TEOS in a cold-wall reactor in the mTorr pressure regime at 1000K. Reactions were followed with Fourier transform infrared spectroscopy. Use of deuterated hydroxyls allowed consumption of hydroxyls by TEOS chemisorption to be distinguished from concurrent formation of SIOH and BOH that results from TEOS decomposition. It was found that TEOS reacts with BOD at twice the rate observed for SIOD demonstrating that hydroxyl groups bonded to boron increase the rate of TEOS chemisorption. Surface ethoxy groups produced by chemisorption of TEOS decompose at a slower rate in the presence of TMB decomposition products. Possible dependencies on reactor geometries and other deposition conditions may determine which of these two competing effects will control deposition rates. This may explain (in part) why the rate enhancement effect is not always observed in boron-doped SiO{sub 2} CVD processes.

  11. Femtosecond laser spectroscopy and DFT studies of photochromic dithizonatomercury complexes.

    PubMed

    von Eschwege, Karel G; Bosman, Gurthwin; Conradie, Jeanet; Schwoerer, Heinrich

    2014-02-01

    The ultrafast dynamics of the photochromic reaction of dithizonatophenylmercury(II) was recently reported. For purpose of investigating the effect of electronically different substituents (X = o-F, m-F, p-F, p-Cl, o-CH3, m-CH3, p-CH3, m,p-diCH3, p-OCH3, o-SCH3, and p-SCH3) on this reaction, a series of phenyl-substituted dithizones were synthesized and complexed with phenylmercury(II). A variation of more than 3 ps in ground state repopulation times was observed, with the o-methyl derivative absorbing both at shortest wavelength and having the fastest repopulation time, while the p-S-methyl derivative lies at the opposite extremity. An increase in both decay times and λmax values is generally reflected by an increase in electron density in the chromophore. Ultrafast rates also proved to be dependent on solvent polarity, while a profound solvatochromic effect was observed in the transition state absorbance. Density functional theory realistically simulated isomer stabilities, electronic spectra and molecular orbitals. Increased electron density enhances stability in the photoexcited blue isomer relative to the orange resting state, as seen from a comparison between orange and blue isomer total bonding energies. A linear trend between computed HOMO energies and experimental λmax of related aliphatic substituted derivatives was found. PMID:24422764

  12. The New World whirligig beetles of the genus Dineutus Macleay, 1825 (Coleoptera, Gyrinidae, Gyrininae, Dineutini).

    PubMed

    Gustafson, Grey T; Miller, Kelly B

    2015-01-01

    All New World members of the whirligig beetle genus Dineutus Macleay, 1825 are treated. The New World Dineutus are found to be composed of 18 species and 6 subspecies: one species, Dineutusmexicanus Ochs, 1925, stat. n. is elevated from subspecies to species rank, and the subspecies Dineutuscarolinusmutchleri Ochs, 1925, syn. n. is synonymized here with the typical form. Lectotypes are designated for Dineutusdiscolor Aubé, 1838, Dineutesmetallicus Aubé, 1838, Dineutussolitarius Aubé, 1838, Dineutesanalis Régimbart, 1883, and Gyrinuslongimanus Olivier, 1795. Each taxonomic unit is provided with a taxonomic history, type locality, diagnosis, distribution, habitat information, and a discussion section. The aedeagus and male mesotarsal claws are illustrated, and dorsal and ventral habitus images of both sexes, for each species and subspecies are provided. General distribution maps are provided for all taxonimc units. A key to the genera of New World Gyrinidae, as well as all the New World Dineutus species is provided. General Dineutus anatomy as well as a clarification of homology and anatomical terms is included.

  13. The New World whirligig beetles of the genus Dineutus Macleay, 1825 (Coleoptera, Gyrinidae, Gyrininae, Dineutini)

    PubMed Central

    Gustafson, Grey T.; Miller, Kelly B.

    2015-01-01

    Abstract All New World members of the whirligig beetle genus Dineutus Macleay, 1825 are treated. The New World Dineutus are found to be composed of 18 species and 6 subspecies: one species, Dineutus mexicanus Ochs, 1925, stat. n. is elevated from subspecies to species rank, and the subspecies Dineutus carolinus mutchleri Ochs, 1925, syn. n. is synonymized here with the typical form. Lectotypes are designated for Dineutus discolor Aubé, 1838, Dineutes metallicus Aubé, 1838, Dineutus solitarius Aubé, 1838, Dineutes analis Régimbart, 1883, and Gyrinus longimanus Olivier, 1795. Each taxonomic unit is provided with a taxonomic history, type locality, diagnosis, distribution, habitat information, and a discussion section. The aedeagus and male mesotarsal claws are illustrated, and dorsal and ventral habitus images of both sexes, for each species and subspecies are provided. General distribution maps are provided for all taxonimc units. A key to the genera of New World Gyrinidae, as well as all the New World Dineutus species is provided. General Dineutus anatomy as well as a clarification of homology and anatomical terms is included. PMID:25685002

  14. Isotope Fractionation Associated with the Indirect Photolysis of Substituted Anilines in Aqueous Solution.

    PubMed

    Ratti, Marco; Canonica, Silvio; McNeill, Kristopher; Bolotin, Jakov; Hofstetter, Thomas B

    2015-11-01

    Organic micropollutants containing aniline substructures are susceptible to different light-induced transformation processes in aquatic environments and water treatment operations. Here, we investigated the magnitude and variability of C and N isotope fractionation during the indirect phototransformation of four para-substituted anilines in aerated aqueous solutions. The model photosensitizers, namely 9,10-anthraquinone-1,5-disulfonate and methylene blue, were used as surrogates for dissolved organic matter chromophores generating excited triplet states in sunlit surface waters. The transformation of aniline, 4-CH3-, 4-OCH3-, and 4-Cl-aniline by excited triplet states of the photosensitizers was associated with inverse and normal N isotope fractionation, whereas C isotope fractionation was negligible. The apparent 15N kinetic isotope effects (AKIE) were almost identical for both photosensitizers, increased from 0.9958±0.0013 for 4-OCH3-aniline to 1.0035±0.0006 for 4-Cl-aniline, and correlated well with the electron donating properties of the substituent. N isotope fractionation is pH-dependent in that H+ exchange reactions dominate below and N atom oxidation processes above the pKa value of the substituted aniline's conjugate acid. Correlations of C and N isotope fractionation for indirect phototransformation were different from those determined previously for the direct photolysis of chloroanilines and offer new opportunities to distinguish between abiotic degradation pathways. PMID:26418612

  15. Fluorinated microemulsions: A study of the phase behavior and structure

    SciTech Connect

    LoNostro, P.; Choi, S.M.; Chen, S.H.; Ku, C.Y.

    1999-06-24

    Fluorinated surfactants have been studied for their peculiar property to form micellar aggregates in water and oils (hydrocarbons or fluorocarbons) and to produce stable microemulsions. Because of their capacity to dissolve large amounts of gases (such as oxygen and carbon dioxide) and for their characteristic physicochemical properties, fluorocarbons have been tested for specific medical purposes, and their microemulsions are among the most promising candidates for the production of suitable blood substitutes and other biocompatible fluids. The authors have synthesized a new partially fluorinated nonionic surfactant, namely, F(CF{sub 2}){sub 7}-CO-(OCH{sub 2}CH{sub 2}){sub 7.2}OCH{sub 3} (I), that forms stable microemulsions with water and perfluorocarbons such as perfluorooctane (PFO). In this paper the authors describe for the first time the phase behaviors of perfluorooctanoic acid (PFOA) in water/PFH and in water/PFO, and that of ester I in water/PFO. Small-angle neutron-scattering (SANS) experiments provide a detailed description of the microstructure of the H{sub 2}O/PFO/PFOA ternary system.

  16. Lewis acid-base adducts of group 13 elements: synthesis, structure and reactivity toward benzaldehyde.

    PubMed

    Ganesamoorthy, C; Matthias, M; Bläser, D; Wölper, C; Schulz, S

    2016-07-28

    Lewis acid-base adducts [LGa-M(C6F5)3] (M = B 1, Al 2, Ga 3) were prepared by the reaction of gallanediyl LGa {L = HC[C(Me)N(2,6-i-Pr2C6H3)]2} with the Lewis acids M(C6F5)3 (M = B, Al, Ga). Benzaldehyde reacts with [LGa-M(C6F5)3] (M = B 1, Al 2) at room temperature with the insertion and formation of [LGa(C6F5){CH(Ph)(OB(C6F5)2)}] (4) and the zwitterionic species [LGa(C6F5){CH(Ph)(OAl(C6F5)2)}] (5), respectively, which was found to decompose at 80 °C with the formation of {(C6F5)2Al(OCH2Ph)}2 (6). Any attempts to isolate the insertion complex of [LGa-Ga(C6F5)3] with benzaldehyde failed and only {(C6F5)2Ga(OCH2Ph)}2 (7) was isolated at elevated temperatures. 2-5 and 7 were structurally characterized by heteronuclear NMR spectroscopy and single crystal X-ray diffraction.

  17. Capsaicin, a tasty free radical scavenger: mechanism of action and kinetics.

    PubMed

    Galano, Annia; Martínez, Ana

    2012-01-26

    The free radical scavenging activity of capsaicin (CAP), which is the pungent component of hot chili peppers, has been studied in aqueous and lipid solutions, using the density functional theory. Different mechanisms of reaction have been considered: single electron transfer (SET), hydrogen transfer (HT), and radical adduct formation (RAF). Rate constants and branching ratios of the different channels of reaction are provided, as well as an interpretation of the UV-vis spectra. CAP is predicted to react faster in aqueous solution than in nonpolar media with oxygenated free radicals, and it was found to be a more efficient scavenger than melatonin and caffeine. It was also found that while SET does not contribute to the overall reactivity of CAP toward (•)OOH, (•)OOCH(3), and (•)OCH(3) radicals, it might be important for the reactions with more electrophilic radicals such as (•)OH, (•)OCCl(3), and (•)OOCCl(3). The main process, responsible for the peroxyl scavenging activity of CAP, was found to be the HT from the OH phenolic group. For the reaction with (•)OCH(3), on the other hand, the HT from allylic sites are predicted to be the main channels of reaction. In this particular case a wider product distribution is predicted. This supports the role of the reacting free radical on the preponderant mechanism of action of free radical scavengers. PMID:22188587

  18. Design of peptides with α,β-dehydro-residues: syntheses, crystal structures and molecular conformations of two ΔPhe-Trp containing peptides

    NASA Astrophysics Data System (ADS)

    Vijayaraghavan, R.; Makker, J.; Kumar, P.; Dey, S.; Singh, T. P.

    2003-06-01

    The ΔPhe-Trp is a newly designed moiety that was found inducing a unique conformation in peptides. The peptides Boc-L-Val-ΔPhe-L-Trp-OCH 3 (I) and Boc-L-Leu-ΔPhe-L-Trp-OCH 3 (II) were synthesized by azlactone method in solution phase. The peptide (I) was crystallized from its solution in ethanol-water mixture in orthorhombic space group P2 12 12 1 with a=10.663(3) Å, b=11.204(3) Å, c=26.516(10) Å and peptide (II) was crystallized from its solution in acetone in a monoclinic space group P2 1 with a=9.354(1)Å, b=11.218(4)Å, c=15.633(1)Å and β=101.83(1)°. The structures were determined by direct methods. Peptide (I) was refined to an R value of 0.059 for 1554 observed reflections [ I≥2 σ (I)] and peptide (II) was refined to an R value of 0.043 for 2920 observed reflections [ I≥2 σ (I)]. The structures of peptides (I) and (II) were found to be identical. They formed an unusual type VIa β-turn conformation which is observed for the first time with a ΔPhe residue at ( i+2) position indicating a unique influence of ΔPhe-Trp moiety in inducing a reproducible new structure in peptides.

  19. OH Production from Reactions of Organic Peroxy Radicals with HO2 : Recent Studies on Ether-Derived Peroxy Radicals

    NASA Astrophysics Data System (ADS)

    Orlando, J. J.; Tyndall, G. S.; Kegley Owen, C. S.; Reynoldson, N.

    2013-12-01

    There is now ample evidence supporting significant formation of OH radicals in the reaction of HO2 with certain organic peroxy radicals (RO2). These reaction channels serve to promote radical propagation, and thus have the potential to alter HOx budgets and partitioning and hence tropospheric oxidative capacity. While much focus has been placed on OH production from reactions involving carbonyl-containing RO2 species, it is also the case that other oxygen- substituted peroxy species (e.g., CH3OCH2OO, HOCH2OO) likely generate OH in their reactions with HO2 (see ref. 1 and refs therein). In this work, the Cl-atom-initiated oxidation of two ethers, diethyl and diisopropyl ether, is investigated over ranges of conditions in an environmental chamber, using both FTIR and GC-FID methods for product quantification. Preliminary analysis suggests that significant OH production is occurring in the reaction of HO2 with CH3CH2OCH(OO)CH3, and also provides evidence for a rapid unimolecular reaction of diisopropyl ether-derived peroxy radicals. Details of these and other results will be described. 1. Orlando, J. J., and G. S. Tyndall, 2012: Laboratory studies of organic peroxy radical chemistry: an overview with emphasis on recent issues of atmospheric significance, Chemical Society Reviews, 41, 6294-6317, doi: 10.1039/C2CS35166H.

  20. Molecular properties of protonated homogeneous and mixed carbon oxide and carbon dioxide clusters

    NASA Astrophysics Data System (ADS)

    Szymczak, Jaroslaw J.; Roszak, Szczepan; Gora, Robert W.; Leszczynski, Jerzy

    2003-10-01

    The molecular structures and characteristics of CO and CO2 protonated homogeneous and mixed complexes were studied by theoretical, ab initio calculations. The thermodynamics, vibrational properties, charge distribution, and interaction energy decomposition components are investigated as a function of the increasing size of clusters. The study reveals the similarities and differences between homogeneous protonated carbon oxide and protonated carbon dioxide clusters. In the first-order approximation the structural differences between (CO)nH+ and (CO2)nH+ clusters are the consequence of the electronic charge distribution in the protonated OCH+ and OCOH+ core fragments. The symmetry of protonated dimers, constituting the cationic core of clusters is the second important factor in determining the overall structure of extended complexes. The OCH+ as well as the OCOH+ fragments are stabilized by cluster formation. The structures and energetics of complexes emerge as a balance between competing electrostatic, exchange, and covalent interactions. The directional covalent forces prevail and enforce the structure of the complexes, however. A universal approach is proposed which allows for the computation of interaction energies for chemical reactions involving significant relaxation of the reactants.

  1. (Acetonitrile){2-[bis-(pyridin-2-ylmethyl-κ(2)N)amino-κN]-N-(2,6-dimethyl-phen-yl)acetamide-κO}(perchlorato-κO)zinc (acetonitrile){2-[bis-(pyridin-2-ylmethyl-κ(2)N)amino-κN]-N-(2,6-dimethyl-phen-yl)acetamide-κO}zinc tris-(perchlorate).

    PubMed

    Astrand, Ove Alexander Høgmoen; Görbitz, Carl Henrik; Kristoffersen, Kenneth Aase; Rongved, Pål

    2013-02-01

    In the title salt, [Zn(C(22)H(24)N(4)O)(CH(3)CN)][Zn(ClO(4))(C(22)H(24)N(4)O)(CH(3)CN)](ClO(4))(3), two differently coordinated zinc cations occur. In the first complex, the metal ion is coordinated by the N,N',N'',O-tetra-dentate acetamide ligand and an acetonitrile N atom, generating an approximate trigonal-bipyramidal coordination geometry, with the O atom in an equatorial site and the acetonitrile N atom in an axial site. In the second complex ion, a perchlorate ion is also bonded to the zinc ion, generating a distorted trans-ZnO(2)N(4) octa-hedron. Of the uncoordinating perchlorate ions, one lies on a crystallographic twofold axis and one lies close to a twofold axis and has a site occupancy of 0.5. N-H⋯O and N-H⋯(O,O) hydrogen bonds are observed in the crystal. Disordered solvent mol-ecules occupy about 11% of the unit-cell volume; their contribution to the scattering was removed with the SQUEEZE routine of the PLATON program [Spek (2009 ▶). Acta Cryst. D65, 148-155.]. PMID:23424407

  2. Isotope Fractionation Associated with the Indirect Photolysis of Substituted Anilines in Aqueous Solution.

    PubMed

    Ratti, Marco; Canonica, Silvio; McNeill, Kristopher; Bolotin, Jakov; Hofstetter, Thomas B

    2015-11-01

    Organic micropollutants containing aniline substructures are susceptible to different light-induced transformation processes in aquatic environments and water treatment operations. Here, we investigated the magnitude and variability of C and N isotope fractionation during the indirect phototransformation of four para-substituted anilines in aerated aqueous solutions. The model photosensitizers, namely 9,10-anthraquinone-1,5-disulfonate and methylene blue, were used as surrogates for dissolved organic matter chromophores generating excited triplet states in sunlit surface waters. The transformation of aniline, 4-CH3-, 4-OCH3-, and 4-Cl-aniline by excited triplet states of the photosensitizers was associated with inverse and normal N isotope fractionation, whereas C isotope fractionation was negligible. The apparent 15N kinetic isotope effects (AKIE) were almost identical for both photosensitizers, increased from 0.9958±0.0013 for 4-OCH3-aniline to 1.0035±0.0006 for 4-Cl-aniline, and correlated well with the electron donating properties of the substituent. N isotope fractionation is pH-dependent in that H+ exchange reactions dominate below and N atom oxidation processes above the pKa value of the substituted aniline's conjugate acid. Correlations of C and N isotope fractionation for indirect phototransformation were different from those determined previously for the direct photolysis of chloroanilines and offer new opportunities to distinguish between abiotic degradation pathways.

  3. Pyrolysis of silica-immobilized benzyl phenyl ether: Competing radical rearrangement pathways under restricted diffusion

    SciTech Connect

    Buchanan, A.C. III; Britt, P.F.; Skeen, J.T.; Struss, J.A.; Elam, C.L.

    1998-12-25

    Pyrolysis studies of silica-immobilized benzyl phenyl ether ({approx}PhOCH{sub 2}Ph or {approx}BPE), a model for related ether structures in fuel resources, have been conducted at 275--325 C to examine the impact of restricted mass transport on the pyrolysis mechanism compared with previous studies in fluid phases. Significant rearrangement chemistry is observed for {approx}BPE occurring through two competitive free-radical pathways that are both promoted by the diffusional constraints. One path involves recombination of incipient benzyl and surface-bound phenoxy radicals to form benzylphenol isomers, 10. The second, previously unreported rearrangement path for {approx}BPE involves a 1,2-phenyl shift in an intermediate radical, {approx}PhOCH{center_dot}Ph, leading to formation of benzhydrol (8) and benzophenone (9) as principal products. The rearrangement products 8--10 typically account for ca. 50% of the pyrolysis products. However, the path selectivity is a sensitive function of {approx}BPE surface coverage and the presence of spacer molecules that either facilitate or hinder hydrogen atom transfer steps on the surface.

  4. Capsaicin, a tasty free radical scavenger: mechanism of action and kinetics.

    PubMed

    Galano, Annia; Martínez, Ana

    2012-01-26

    The free radical scavenging activity of capsaicin (CAP), which is the pungent component of hot chili peppers, has been studied in aqueous and lipid solutions, using the density functional theory. Different mechanisms of reaction have been considered: single electron transfer (SET), hydrogen transfer (HT), and radical adduct formation (RAF). Rate constants and branching ratios of the different channels of reaction are provided, as well as an interpretation of the UV-vis spectra. CAP is predicted to react faster in aqueous solution than in nonpolar media with oxygenated free radicals, and it was found to be a more efficient scavenger than melatonin and caffeine. It was also found that while SET does not contribute to the overall reactivity of CAP toward (•)OOH, (•)OOCH(3), and (•)OCH(3) radicals, it might be important for the reactions with more electrophilic radicals such as (•)OH, (•)OCCl(3), and (•)OOCCl(3). The main process, responsible for the peroxyl scavenging activity of CAP, was found to be the HT from the OH phenolic group. For the reaction with (•)OCH(3), on the other hand, the HT from allylic sites are predicted to be the main channels of reaction. In this particular case a wider product distribution is predicted. This supports the role of the reacting free radical on the preponderant mechanism of action of free radical scavengers.

  5. Mechanistic and kinetic study on the reactions of coumaric acids with reactive oxygen species: a DFT approach.

    PubMed

    Garzón, Andrés; Bravo, Iván; Barbero, Antonio J; Albaladejo, José

    2014-10-01

    The mechanism and kinetics of reactions between coumaric acids and a series of reactive oxygen species ((•)OX) was studied through the density functional theory (DFT). H atom abstraction from -OH and -COOH groups and addition to the nonaromatic double bond were the most representative reaction pathways chosen for which free energy barriers and rate constants were calculated within the transition state theory (TST) framework. From these calculations, it was estimated that (•)OH > (•)OCH3 > (•)OOH > (•)OOCH3 is the order of reactivity of (•)OX with any coumaric acid. The highest rate constant was estimated for p-coumaric acid + (•)OH reaction, whereas the rest of the (•)OX species are more reactive with o-coumaric acid. On the basis of the calculated rate constants, H abstraction from a -OH group should be the main mechanism for the reactions involving (•)OCH3, (•)OOH, and (•)OOCH3 radicals. Nevertheless, the addition mechanism, which sometimes is not considered in theoretical studies on reactions of phenolic compounds with electrophilic species, could play a relevant role in the global mechanism of coumaric acid + (•)OH reactions.

  6. Model biogas steam reforming in a thin Pd-supported membrane reactor to generate clean hydrogen for fuel cells

    NASA Astrophysics Data System (ADS)

    Iulianelli, A.; Liguori, S.; Huang, Y.; Basile, A.

    2015-01-01

    Steam reforming of a model biogas mixture is studied for generating clean hydrogen by using an inorganic membrane reactor, in which a composite Pd/Al2O3 membrane separates part of the produced hydrogen through its selective permeation. The characteristics of H2 perm-selectivity of the fresh membrane is expressed in terms of H2/N2 ideal selectivity, in this case equal to 4300. Concerning biogas steam reforming reaction, at 380 °C, 2.0 bar H2O:CH4 = 3:1, GHSV = 9000 h-1 the permeate purity of the recovered hydrogen is around 96%, although the conversion (15%) and hydrogen recovery (>20%) are relatively low; on the contrary, at 450 °C, 3.5 bar H2O:CH4 = 4:1, GHSV = 11000 h-1 the conversion is increased up to more than 30% and the recovery of hydrogen to about 70%. This novel work constitutes a reference study for new developments on biogas steam reforming reaction in membrane reactors.

  7. Immobilization of nanobeads on a surface to control the size, shape and distribution of pores in electrochemically generated sol-gel films

    PubMed Central

    Ciabocco, Michela; Berrettoni, Mario; Zamponi, Silvia

    2015-01-01

    Electrochemically assisted deposition of an ormosil film at a potential where hydrogen ion is generated as the catalyst yields insulating films on electrodes. When the base electrode is modified with 20-nm poly(styrene sulfonate), PSS, beads bound to the surface with 3-aminopropyltriethoxysilane (APTES) and using (CH3)3SiOCH3 as the precursor, the resulting film of organically modified silica (ormosil) has cylindrical channels that reflect both the diameter of the PSS and the distribution of the APTES-PSS on the electrode. At an electrode modified by a 20-min immersion in 0.5 mmol dm-3 APTES followed by a 30-s immersion in PSS, a 20-min electrolysis at 1.5 V in acidified (CH3)3SiOCH3 resulted in an ormosil film with 20-nm pores separated by 100 nm. Cyclic voltammetry of Ru(CN)64- at scan rates above 5 mVs-1 yielded currents controlled primarily by linear diffusion. Below 5 mVs-1, convection rather than the expected factor, radial diffusion, apparently limited the current. PMID:26167128

  8. Mechanism and kinetic properties of OH-initiated atmospheric oxidation degradation of methamidophos in the presence of O2/NO

    NASA Astrophysics Data System (ADS)

    Shi, Xiangli; Zhang, Ruiming; Zhang, Qingzhu; Wang, Wenxing

    2016-05-01

    Methamidophos is a member of the organophosphorus insecticides. In the present work, the mechanism of the OH radical-initiated atmospheric oxidation degradation of methamidophos and the possible degradation products were investigated with the aid of quantum chemical calculations. The geometrical parameters and vibrational frequencies were calculated at the MPWB1K/6-31+G(d,p) level. The energies of all the stationary points were carried out at the MPWB1K/6-311+G(3df,2p) level of theory. The rate constants of key elementary steps involved in the OH radical-initiated atmospheric degradation of methamidophos were calculated by meaning of the canonical variation transition-state (CVT) theory with the small curvature tunneling (SCT) correction over the possible atmospheric temperature range of 273-333 K. The rate-temperature formulas were fitted for the first time. The pre-exponential factor and the activation energy were obtained. Studies show that the OH additions from the trans-positions of the NH2 and OCH3 groups, the H abstractions from the SCH3 and OCH3 groups as well as the substitution reaction resulting in the products of CH3OP(O)OHNH2 and SCH3 are thermodynamically favorable reaction pathways for the reaction of methamidophos with OH radicals due to the low barrier and strong exothermicity.

  9. The antiproliferative effect of hexadecylphosphocholine toward HL60 cells is prevented by exogenous lysophosphatidylcholine.

    PubMed

    Boggs, K; Rock, C O; Jackowski, S

    1998-01-01

    The mechanisms that account for the anti-proliferative properties of the biologically active lysophospholipid analog hexadecylphosphocholine (HexPC) were investigated in HL60 cells. HexPC inhibited the incorporation of choline into phosphatidylcholine and the pattern of accumulation of soluble choline-derived metabolites pinpointed CTP:phosphocholine cytidylyltransferase (CT) as the inhibited step in vivo. HexPC also inhibited recombinant CT in vitro. HexPC treatment led to accumulation of cells in G2/M phase, triggered DNA fragmentation and caused morphological changes associated with apoptosis. The supplementation of HexPC-treated cells with exogenous lysophosphatidylcholine (LPC) completely reversed the cytotoxic effects of HexPC and restored HL60 cell proliferation in the presence of the drug. LPC provided an alternate pathway for phosphatidylcholine synthesis via the acylation of exogenous LPC. This result contrasted with the response of HL60 cells to 1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine (ET-18-OCH3) where LPC overcame the cytotoxic effects but did not support continued cell proliferation. Morphological integrity, DNA stability and cell viability were maintained in cells treated with LPC plus either antineoplastic agent. Thus the inhibition of phosphatidylcholine biosynthesis at the CT step accounts for the cytotoxicity of both HexPC and ET-18-OCH3 which is overridden by providing an alternate pathway for phosphatidylcholine synthesis via the acylation of exogenous LPC.

  10. Visible-Light-Induced Olefin Activation Using 3D Aromatic Boron-Rich Cluster Photooxidants.

    PubMed

    Messina, Marco S; Axtell, Jonathan C; Wang, Yiqun; Chong, Paul; Wixtrom, Alex I; Kirlikovali, Kent O; Upton, Brianna M; Hunter, Bryan M; Shafaat, Oliver S; Khan, Saeed I; Winkler, Jay R; Gray, Harry B; Alexandrova, Anastassia N; Maynard, Heather D; Spokoyny, Alexander M

    2016-06-01

    We report a discovery that perfunctionalized icosahedral dodecaborate clusters of the type B12(OCH2Ar)12 (Ar = Ph or C6F5) can undergo photo-excitation with visible light, leading to a new class of metal-free photooxidants. Excitation in these species occurs as a result of the charge transfer between low-lying orbitals located on the benzyl substituents and an unoccupied orbital delocalized throughout the boron cluster core. Here we show how these species, photo-excited with a benchtop blue LED source, can exhibit excited-state reduction potentials as high as 3 V and can participate in electron-transfer processes with a broad range of styrene monomers, initiating their polymerization. Initiation is observed in cases of both electron-rich and electron-deficient styrene monomers at cluster loadings as low as 0.005 mol%. Furthermore, photo-excitation of B12(OCH2C6F5)12 in the presence of a less activated olefin such as isobutylene results in the production of highly branched poly(isobutylene). This work introduces a new class of air-stable, metal-free photo-redox reagents capable of mediating chemical transformations. PMID:27186856

  11. Cu(II) complexes bearing the 2,2,2-tris(1-pyrazolyl)ethanol or 2,2,2-tris(1-pyrazolyl)ethyl methanesulfonate scorpionates. X-Ray structural characterization and application in the mild catalytic peroxidative oxidation of cyclohexane.

    PubMed

    Silva, Telma F S; Mishra, Gopal S; da Silva, M Fátima Guedes; Wanke, Riccardo; Martins, Luísa M D R S; Pombeiro, Armando J L

    2009-11-14

    Reactions between CuCl2 and the functionalized scorpionate 2,2,2-tris(1-pyrazolyl)ethanol HOCH2C(pz)3 1 (pz = pyrazolyl) or 2,2,2-tris(1-pyrazolyl)ethyl methanesulfonate CH3SO2OCH2C(pz)3 2 yield the corresponding water soluble CuII complexes [CuCl2{HOCH2C(pz)3}] 3 or [CuCl2{CH3SO2OCH2C(pz)3}]2 4. In 3 the scorpionate ligand shows the typical N,N,N-coordination mode, whereas in the dinuclear complex 4 it binds the metal as a bidentate species. Compounds 1-4 have been characterized by IR, far-IR, elemental analysis and (for 2-4) single crystal X-ray diffraction. The new scorpionate complexes 3 and 4 are shown to act as catalyst precursors for the peroxidative oxidation of cyclohexane to cyclohexanol (main product) and cyclohexanone, under mild conditions (at room temperature and using an aqueous solution of H2O2) reaching TON values up to 186 in NCMe/H2O. Their hydrosolubility allows them to operate also in pure aqueous media (without any organic solvent, although less effectively), a rare feature of significance towards a green alkane oxidation process. PMID:20449198

  12. One-pot solvothermal synthesis of a well-ordered layered sodium aluminoalcoholate complex: a useful precursor for the preparation of porous Al2O3 particles

    SciTech Connect

    Li, XS; Michaelis, VK; Ong, TC; Smith, SJ; McKay, I; Muller, P; Griffin, RG; Wang, EN

    2014-01-01

    One-pot solvothermal synthesis of a robust tetranuclear sodium hexakis(glycolato)tris(methanolato)aluminate complex Na-3[Al-4(OCH3)(3)(OCH2CH2O)(6)] via a modified yet rigorous base-catalyzed transesterification mechanism is presented here. Single crystal X-ray diffraction (SCXRD) studies indicate that this unique Al complex contains three pentacoordinate Al3+ ions, each bound to two bidentate ethylene glycolate chelators and one monodentate methanolate ligand. The remaining fourth Al3+ ion is octahedrally coordinated to one oxygen atom from each of the six surrounding glycolate chelators, effectively stitching the three pentacoordinate Al moieties together into a novel tetranuclear Al complex. This aluminate complex is periodically self-assembled into well-ordered layers normal to the [110] axis with the intra-/inter-layer bonding involving extensive ionic bonds from the three charge-counterbalancing Na+ cations rather than the more typical hydrogen bonding interactions as a result of fewer free hydroxyl groups present in its structure. It can also serve as a valuable precursor toward the facile synthesis of high-surface-area alumina powders using a very efficient rapid pyrolysis technique.

  13. Electronic Structure and Optical Properties of Boron Difluoride Dibenzoylmethane Derivatives.

    PubMed

    Tikhonov, Sergey A; Vovna, Vitaliy I; Gelfand, Natalia A; Osmushko, Ivan S; Fedorenko, Elena V; Mirochnik, Anatoliy G

    2016-09-22

    Electronic structure and optical properties of boron difluoride dibenzoylmethanate BF2Dbm and its four derivatives were studied using X-ray photoelectron spectroscopy, absorption and luminescence spectroscopy, and quantum chemistry (DFT and TDDFT). In a series of the studied compounds, the relationship of molecular design and optical properties has been revealed. At the transition from BF2Dbm to BF2Dbm(OCH3)2, the HOMO-LUMO energy gap decreases, resulting in a bathochromic shift of the optical spectra. Substitution of one methoxy group by the nitro group in BF2Dbm(OCH3)2 causes a decrease in the contribution of the chelate ring π-orbital in the LUMO, resulting in a lower value of charge transfer from the substituents to the chelate ring in the case of the first excited state, which determines the characteristics of the main absorption bands. The nitro group transition from the m- to p-position of the benzene ring causes a change in the nature of the main bands of the optical spectra due to the increase of the splitting value of the LUMO and LUMO+1 levels. The main band in the optical spectra of the complex containing the C10H7 group is associated with the charge transfer transitions. PMID:27580170

  14. The effect of a paramagnetic metal ion within a molecule: comparison of the structurally identical paramagnetic [3,3-Fe(1,2-C2B9H11)2]- with the diamagnetic [3,3-Co(1,2-C2B9H11)2]- sandwich complexes.

    PubMed

    Cioran, Ana M; Teixidor, Francesc; Viñas, Clara

    2015-02-14

    Derivatives of the ferrabisdicarbollide [3,3'-Fe(1,2-C(2)B(9)H(11))(2)](-) have been produced starting from the zwitterion [3,3'-Fe(8-(OCH(2)CH(2))(2)-1,2-C(2)B(9)H(10))(1',2'-C(2)B(9)H(11))], 1, upon reaction with nucleophiles: alkoxides, halides and hydrosulfide ions HS(-). The result has been the preparation of [3,3'-Fe(8-(OCH(2)CH(2))(2)R/X-1,2-C(2)B(9)H(10))(1',2'-C(2)B(9)H(11))] (R = OMe, [2](-); OEt, [3](-); OCH(2)CH(2)OCH(3), [4](-); and X = Cl, [5](-); Br, [6](-); I, [7](-); and SH, [8](-)). The reaction behavior of is comparable to the well-studied cobalt equivalent, [3,3'-Co(8-(OCH(2)CH(2))2-1,2-C(2)B(9)H(10))(1',2'-C(2)B(9)H(11))], and the yields and stability of the resulting complexes are similar. These results are relevant taking into account that [3,3'-Fe(1,2-C(2)B(9)H(11))(2))(-) is a paramagnetic anion. Implications of this are observed in the (11)B-, (1)H and (13)C NMR spectra of [3,3'-Co(1,2-C(2)B(9)H(11))(2)](-) and [3,3'-Fe(1,2-C(2)B(9)H(11))(2)](-) that having identical sandwich molecular structures and the same negative charge have absolutely different widths of the NMR field, between 15 and -25 ppm for [3,3'-Co(1,2-C(2)B(9)H(11))(2)](-) and in the range 150 to -550 ppm for [3,3'-Fe(1,2-C(2)B(9)H(11))(2)](-). The sharpness of both spectra is on the other hand comparable, although no B-H couplings are observed in the Fe metallacarborane or its derivatives. Remarkable is the comparative influence vs. [3,3'-Co(1,2-C(2)B(9)H(11))(2)](-) of replacing Co by Fe on the elements of the cluster layer nearest to the metal. The two equivalent C cluster (Cc) atoms are influenced at 36 840 Hz, the two equivalent B atoms that are adjacent to the two Cc are influenced at 38 157 Hz and the single B that is adjacent to the two B atoms is influenced at 44 062 Hz. Remarkable is the similar influence on B and on C, taking into account that the values have been obtained from two distinct NMR spectra of (11)B and (13)C. The {(11)B-(11)B} COSY NMR and {(1)H

  15. Study of the photon-induced formation and subsequent desorption of CH3OH and H2CO in interstellar ice analogs

    NASA Astrophysics Data System (ADS)

    Martín-Doménech, R.; Muñoz Caro, G. M.; Cruz-Díaz, G. A.

    2016-05-01

    Context. Methanol and formaldehyde are two simple organic molecules that are ubiquitously detected in the interstellar medium, in both the solid and gaseous phases. An origin in the solid phase and a subsequent nonthermal desorption into the gas phase is often invoked to explain their abundances in some of the environments where they are found. Experimental simulations under astrophysically relevant conditions have been carried out in the past four decades in order to find a suitable mechanism for that process. Aims: In particular, photodesorption from pure methanol ice (and presumably from pure formaldehyde ice) has been found to be negligible in previous works, probably because both molecules are very readily dissociated by vacuum-UV photons. Therefore, we explore the in situ formation and subsequent photon-induced desorption of these species, studying the UV photoprocessing of pure ethanol ice, and a more realistic binary H2O:CH4 ice analog. Methods: Experimental simulations were performed in an ultra-high vacuum chamber. Pure ethanol and binary H2O:CH4 ice samples deposited onto an infrared transparent window at 8 K were UV-irradiated using a microwave-discharged hydrogen flow lamp. Evidence of photochemical production of these two species and subsequent UV-photon-induced desorption into the gas phase were searched for by means of a Fourier transform infrared spectrometer and a quadrupole mass spectrometer, respectively. After irradiation, ice samples were warmed up to room temperature until complete sublimation was attained for detection of volatile products. Results: Formation of CH3OH was only observed during photoprocessing of the H2O:CH4 ice analog, accounting for ~4% of the initial CH4 ice column density, but no photon-induced desorption was detected. Photochemical production of H2CO was observed in both series of experiments. Formation of formaldehyde accounted for ≤45% conversion of the initial ethanol ice, but it could not be quantified during

  16. Effects of Glutamine and Omega-3 Fatty Acids on Erythrocyte Deformability and Oxidative Damage in Rat Model of Enterocolitis

    PubMed Central

    Cehreli, Ruksan; Akpinar, Hale; Artmann, Aysegul Temiz; Sagol, Ozgul

    2015-01-01

    Background The aim of the study was to investigate preventive effects of glutamine (Gln), omega-3 fatty acids (FA) on erythrocyte deformability (EDEF) in rat model of indomethacin-induced enterocolitis. Methods Nineteen Wistar albino male rats were divided into three groups: control group, colitis induced by indomethacin and were fed with a standard laboratory diet (group 1), and colitis induced by indomethacin and were also fed with Gln, omega-3 FA (group 2). An investigation was performed in a rat model of experimental colitis induced by subcutaneous injections of 2 mL intdomethacine solution applied at 24 and 48 hours intervals to male Wistar rats for 14 days. Gln and omega-3 FA were added to the daily standard diets of the animals during 14 days of injections. During the study, changes in body weight were evaluated. The intestines were examined, and colitis was macroscopic and histologically scored. The circulating tumor necrosis factor alpha (TNF-α) and interleukine-1β (IL-1β), erythrocyte transit time (ETT) and thiobarbituric acid reactive substances (TBARS) levels were determined in addition to calculation of EDEF indices in all groups. Results No significant differences in body weight changes could be determined between the standard diet and special diet groups at the end of the experiment. After macroscopic and microscopic scoring, in all of the groups that colitis was found induced, the lowest microscopic score was observed in the group 2. But Gln and omega-3 FA supplemented diet did not change the mean macroscopic and histological scores in all rats. The proliferating cell nuclear antigen (PCNA) levels were significantly higher in group 1 and group 2 compared to the control group. Effects of the diet on circulating TNF-α and IL-1β levels were found correlated with inflammation but statistically significant differences were not found in the group 1 and group 2 (P < 0.05). The ETT and TBARS levels in standard and special diet groups were significantly

  17. Effect of age on 16.1-km time-trial performance.

    PubMed

    Balmer, James; Bird, Steve; Davison, Richard; Lucia, Alejandro

    2008-01-15

    In this study, we assessed the performance of trained senior (n = 6) and veteran (n = 6) cyclists (mean age 28 years, s = 3 and 57 years, s = 4 respectively). Each competitor completed two cycling tests, a ramped peak aerobic test and an indoor 16.1-km time-trial. The tests were performed using a Kingcycle ergometer with the cyclists riding their own bicycle fitted with an SRM powermeter. Power output, heart rate, and gas exchange variables were recorded continuously and blood lactate concentration [HLa] was assessed 3 min after the peak ramped test and at 2.5-min intervals during the time-trial. Peak values for power output (RMP(max)), heart rate (HR(peak)), oxygen uptake (VO2(peak)), and ventilation (V(Epeak)) attained during the ramped test were higher in the senior group (P < 0.05), whereas [HLa](peak), RER(peak), V(E): VO2(peak), and economy(peak) were similar between groups (P > 0.05). Time-trial values (mean for duration of race) for power output (W(TT)), heart rate (HR(TT)), VO2 (VO(2TT)), and V(E) (V(ETT)) were higher in the seniors (P < 0.05), but [HLa](TT), RER(TT), V(ETT): VO2(TT), and economy(TT) were similar between the groups (P > 0.05). Time-trial exercise intensity, expressed as %RMP(max), %HR(peak), % VO2(peak), and % V(Epeak), was similar (P > 0.05) for seniors and veterans (W(TT): 81%, s = 2 vs. 78%, s = 8; HR(TT): 96%, s = 4 vs. 94%, s = 4; VO2(TT): 92%, s = 4 vs. 95%, s = 10; V(ETT): 89%, s = 8 vs. 85%, s = 8, respectively). Overall, seniors attained higher absolute values for power output, heart rate, VO2, and V(E) but not blood lactate concentration, respiratory exchange ratio (RER), V(E): VO2, and economy. Veterans did not accommodate age-related declines in time trial performance by maintaining higher relative exercise intensity.

  18. Evaluation of the Effect of Tracheal Tube Orientation on Success of Intubation through Intubating Laryngeal Mask Airway

    PubMed Central

    Chhatrapati, Swati; Auti, Subhhash Sadashiv; Aswar, Swapnil Ganesh

    2016-01-01

    Introduction Polyvinyl Chloride Endotracheal Tube (PVC ETT) can be used as an alternative to Fastrach Silicone Wire-Reinforced Tube (FTST) for intubation through Intubating Laryngeal Mask Airway (ILMA) as the latter is expensive and has low volume high pressure cuff. Aim To evaluate the effects of orientation of PVC ETT (normal curve and reverse curve) on the success of intubation through ILMA, haemodynamic response and postoperative sore throat. Materials and Methods Sixty healthy adult patients of ASA physical status I & II scheduled for elective surgery under general anaesthesia requiring endotracheal intubation were randomly divided into two groups. In Normal (N) group (n=30), the tracheal tube was inserted with its natural curve following the 90° curvature of ILMA. In Reverse (R) group (n=30), the tracheal tube was inserted with its natural curve directed opposite to the curvature of ILMA. The time taken to intubate, number of attempts, and maneuvers required for successful endotracheal intubation along with haemodynamics and oxygen saturation were noted. Postoperative sore throat was evaluated using a Verbal Analogue Scale (VAS) (0-10). Qualitative data was analysed by Chi-Square test and Fisher’s exact test. Quantitative data was analysed by unpaired t-test and Mann-Whitney test. Results Placement of ILMA was successful in all patients. Total Intubation Time (mean±SD) in Group N was 12.53±1.78 seconds and in Group R was 11.97±1.33 seconds (p>0.05). Tracheal intubation through ILMA was successful in all patients. First attempt success rate in R Group (26 patients, 86.7%) was higher than N Group (22 patients, 73.3%) (p>0.05). Four patients (13.3%) in R Group and 8 patients (26.7%) in N Group required 2nd step of Chandy’s maneuver during second attempt for successful intubation. Incidence of sore throat 6 hours postoperatively was statistically significant (median value 2.00 in N Group vs. 0.00 in R Group) between two groups. Conclusion PVC ETT with

  19. Role of upper airway ultrasound in airway management.

    PubMed

    Osman, Adi; Sum, Kok Meng

    2016-01-01

    Upper airway ultrasound is a valuable, non-invasive, simple, and portable point of care ultrasound (POCUS) for evaluation of airway management even in anatomy distorted by pathology or trauma. Ultrasound enables us to identify important sonoanatomy of the upper airway such as thyroid cartilage, epiglottis, cricoid cartilage, cricothyroid membrane, tracheal cartilages, and esophagus. Understanding this applied sonoanatomy facilitates clinician to use ultrasound in assessment of airway anatomy for difficult intubation, ETT and LMA placement and depth, assessment of airway size, ultrasound-guided invasive procedures such as percutaneous needle cricothyroidotomy and tracheostomy, prediction of postextubation stridor and left double-lumen bronchial tube size, and detecting upper airway pathologies. Widespread POCUS awareness, better technological advancements, portability, and availability of ultrasound in most critical areas facilitate upper airway ultrasound to become the potential first-line non-invasive airway assessment tool in the future. PMID:27529028

  20. An Interactive Computer Session to Initiate Physical Activity in Sedentary Cardiac Patients: Randomized Controlled Trial

    PubMed Central

    Smith-Ray, Renae L; Dzewaltowski, David A; Glasgow, Russell E; Lee, Rebecca E; Thomas, Deborah SK; Xu, Stanley; Estabrooks, Paul A

    2015-01-01

    Background Physical activity (PA) improves many facets of health. Despite this, the majority of American adults are insufficiently active. Adults who visit a physician complaining of chest pain and related cardiovascular symptoms are often referred for further testing. However, when this testing does not reveal an underlying disease or pathology, patients typically receive no additional standard care services. A PA intervention delivered within the clinic setting may be an effective strategy for improving the health of this population at a time when they may be motivated to take preventive action. Objective Our aim was to determine the effectiveness of a tailored, computer-based, interactive personal action planning session to initiate PA among a group of sedentary cardiac patients following exercise treadmill testing (ETT). Methods This study was part of a larger 2x2 randomized controlled trial to determine the impact of environmental and social-cognitive intervention approaches on the initiation and maintenance of weekly PA for patients post ETT. Participants who were referred to an ETT center but had a negative-test (ie, stress tests results indicated no apparent cardiac issues) were randomized to one of four treatment arms: (1) increased environmental accessibility to PA resources via the provision of a free voucher to a fitness facility in close proximity to their home or workplace (ENV), (2) a tailored social cognitive intervention (SC) using a “5 As”-based (ask, advise, assess, assist, and arrange) personal action planning tool, (3) combined intervention of both ENV and SC approaches (COMBO), or (4) a matched contact nutrition control (CON). Each intervention was delivered using a computer-based interactive session. A general linear model for repeated measures was conducted with change in PA behavior from baseline to 1-month post interactive computer session as the primary outcome. Results Sedentary participants (n=452; 34.7% participation rate) without

  1. The frequency and importance of bronchial hyperreactivity in patients with allergic and non-allergic rhinitis.

    PubMed

    Dziedziczko, A; Gniazdowski, R

    1977-01-01

    A trial was undertaken to evaluate the occurrence of bronchial hyperreactivity, typical of bronchial asthma, in 50 patients with hay fever (rhinitis allergica) and 45 patients with rhinitis vasomotorica nonallergica, as opposed to a group of healthy subjects and patients with bronchial asthma. All the patients were subjected to spirographic examinations at rest (VC, FEV1, ETT, SI), after exercise (PWC170), and after histamine inhalation. The authors believe that it is expedient to study bronchial hyperreactivity in patients with hay fever and rhinitis vasomotorica nonallergica in that it affords possibilities for the prevision of the conceivable unfavourable evolution of the disease towards the atopic or non-atopic bronchial asthma, as well as for the taking of adequate preventive and therapeutic measures. PMID:920144

  2. The Making of a Best-Selling Book on Reproduction: Lennart Nilsson's A Child Is Born.

    PubMed

    Jülich, Solveig

    2015-01-01

    This article examines the 1965 first edition of Swedish photographer Lennart Nilsson's Ett barn blir till (A Child Is Born) by placing the book back in the historical context in which it was produced, marketed, and reviewed. In particular it shows how medicine and the media in Sweden were intertwined in the process of incorporating Nilsson's photographs of aborted embryos and fetuses into a best-selling book on the origin and development of human life. Nilsson's work is related to other books in the same genre as well as the popular picture magazines of the time, in order to highlight how it aspired to offer something new. It is argued that a number of commercial and other interests were involved and that an immense effort went into not only making and promoting the book but also trying to control the meaning of the images.

  3. Humidification on Ventilated Patients: Heated Humidifications or Heat and Moisture Exchangers?

    PubMed Central

    Cerpa, F; Cáceres, D; Romero-Dapueto, C; Giugliano-Jaramillo, C; Pérez, R; Budini, H; Hidalgo, V; Gutiérrez, T; Molina, J; Keymer, J

    2015-01-01

    The normal physiology of conditioning of inspired gases is altered when the patient requires an artificial airway access and an invasive mechanical ventilation (IMV). The endotracheal tube (ETT) removes the natural mechanisms of filtration, humidification and warming of inspired air. Despite the noninvasive ventilation (NIMV) in the upper airways, humidification of inspired gas may not be optimal mainly due to the high flow that is being created by the leakage compensation, among other aspects. Any moisture and heating deficit is compensated by the large airways of the tracheobronchial tree, these are poorly suited for this task, which alters mucociliary function, quality of secretions, and homeostasis gas exchange system. To avoid the occurrence of these events, external devices that provide humidification, heating and filtration have been developed, with different degrees of evidence that support their use. PMID:26312102

  4. Role of upper airway ultrasound in airway management.

    PubMed

    Osman, Adi; Sum, Kok Meng

    2016-01-01

    Upper airway ultrasound is a valuable, non-invasive, simple, and portable point of care ultrasound (POCUS) for evaluation of airway management even in anatomy distorted by pathology or trauma. Ultrasound enables us to identify important sonoanatomy of the upper airway such as thyroid cartilage, epiglottis, cricoid cartilage, cricothyroid membrane, tracheal cartilages, and esophagus. Understanding this applied sonoanatomy facilitates clinician to use ultrasound in assessment of airway anatomy for difficult intubation, ETT and LMA placement and depth, assessment of airway size, ultrasound-guided invasive procedures such as percutaneous needle cricothyroidotomy and tracheostomy, prediction of postextubation stridor and left double-lumen bronchial tube size, and detecting upper airway pathologies. Widespread POCUS awareness, better technological advancements, portability, and availability of ultrasound in most critical areas facilitate upper airway ultrasound to become the potential first-line non-invasive airway assessment tool in the future.

  5. Humidification on Ventilated Patients: Heated Humidifications or Heat and Moisture Exchangers?

    PubMed

    Cerpa, F; Cáceres, D; Romero-Dapueto, C; Giugliano-Jaramillo, C; Pérez, R; Budini, H; Hidalgo, V; Gutiérrez, T; Molina, J; Keymer, J

    2015-01-01

    The normal physiology of conditioning of inspired gases is altered when the patient requires an artificial airway access and an invasive mechanical ventilation (IMV). The endotracheal tube (ETT) removes the natural mechanisms of filtration, humidification and warming of inspired air. Despite the noninvasive ventilation (NIMV) in the upper airways, humidification of inspired gas may not be optimal mainly due to the high flow that is being created by the leakage compensation, among other aspects. Any moisture and heating deficit is compensated by the large airways of the tracheobronchial tree, these are poorly suited for this task, which alters mucociliary function, quality of secretions, and homeostasis gas exchange system. To avoid the occurrence of these events, external devices that provide humidification, heating and filtration have been developed, with different degrees of evidence that support their use.

  6. Variability of the breathing pattern before and after extubation.

    PubMed

    Krieger, B P; Chediak, A; Gazeroglu, H B; Bizousky, F P; Feinerman, D

    1988-04-01

    A stable breathing pattern during unassisted ventilation through an endotracheal tube (ETT) prior to extubation is an important factor in determining whether a patient can be successfully extubated. Proper interpretation of changes in the breathing pattern requires knowledge of the normal variability of the breathing pattern in critically ill, intubated patients. To establish these guidelines, 50 spontaneously breathing patients who were being weaned from mechanical ventilation were monitored with respiratory inductive plethysmography for one hour immediately prior to and following successful extubation. Immediately after extubation, respiratory rate (f), tidal volume (VT), minute ventilation, and mean inspiratory flow increased slightly. By 30 minutes postextubation, these parameters were similar to preextubation values. There was no significant change in variability of f or VT. Although the breathing pattern of these relatively stable, intensive care patients differed from values of normal ambulatory subjects, values were similar in the preextubation and postextubation periods.

  7. Inelastic neutron scattering from single crystal Zn under high pressure

    NASA Astrophysics Data System (ADS)

    Morgan, J. G.; von Dreele, R. B.; Wochner, P.; Shapiro, S. M.

    1996-07-01

    Inelastic neutron-scattering experiments have been performed for single crystals of Zn under pressures up to 8.8 GPa at 300 K. The phonon modes q/qmax=ξ=0.075 and ξ=0.10 were measured in the transverse acoustic branch Σ3, where q=0 corresponds with the elastic constant C44. The phonon energy showed a substantial hardening with increasing pressure. The experimental data below 6.8 GPa for ξ=0.075 yield a constant Grüneisen mode γi=-lnωi/lnV of 2.25 in good agreement with a previous calculation [H. Ledbetter, Phys. Status Solidi B 181, 81 (1994)]. Above 6.8 GPa, there is a very rapid increase of γi which is indicative of the presence of a giant Kohn anomaly. This rapid divergence at high pressure indicates that a phonon softening may occur at pressures higher than 8.8 GPa caused by the collapse of the giant Kohn anomaly via an electronic topological transition (ETT). In an earlier Mössbauer Zn study at 4 K [W. Potzel et al., Phys. Rev. Lett. 74, 1139 (1994)], a drastic drop of the Lamb-Mössbauer factor was observed at 6.6 GPa, which was interpreted as being due to phonon softening, indicating this ETT had occurred. This paper also compares the compressibility data for single crystal Zn and Zn powder using neutron scattering. The results were found to be similar to an earlier x-ray Zn powder experiment [O. Schulte et al., High Pressure Res. 6, 169 (1991)].

  8. Determinants of developing diabetes mellitus and vascular complications in patients with impaired fasting glucose

    PubMed Central

    Sharifi, Faranak; Jaberi, Yahya; Mirzamohammadi, Fatemeh; Mirzamohammadi, Hamid; Mousavinasab, Nouraddin

    2013-01-01

    Aims: To detect the risk factors of diabetes mellitus (DM) and cardiovascular complications in subjects with impaired fasting glucose (IFG). Materials and Methods: One hundred and twenty three subjects with proved IFG in Zanjan Healthy Heart Study (2002-2003) were recalled and participated in this study (2009-2010). Demographic and laboratoryinformation of the participants were collected.Ischemic heart disease (IHD) was assessed by the exercise tolerance test (ETT). All the subjects with abnormal ETT or documented past history of IHD confirmed by angiographic evaluation. Ophthalmic complications including cataract, glaucoma, and diabetic retinopathy were estimated by an ophthalmologist. Results: Incidence of DM was 19.5%. All the diabetic and pre-diabetic patients had at least one of the other components of metabolic syndrome. Obesity (P: 0.04, OR: 1.8, 95%CI: 1.2-9) and low physical activity (P < 0.001, OR: 9.6, 95%CI: 3.4-32) were the only independent prognostic risk factors for progression to DM in patients with IFG. Total incidence of IHD was 14.6% and had a strong correlation with sex (P: 0.01, OR: 1.8, 95%CI: 1.2-1.5), age (P < 0.001, OR: 23, 95%CI: 2.1-67) and cigarette smoking (P < 0.001, OR: 36.5, 95%CI: 3.9-337). Non-proliferative diabetic retinopathy was shown in 2 (1.6%) subjects who were all women. Conclusion: Obesity and low physical activity are the main factors of developing DM and its macrovascular complications in subjects with IFG. PMID:24083174

  9. The complex of ASYMMETRIC LEAVES (AS) proteins plays a central role in antagonistic interactions of genes for leaf polarity specification in Arabidopsis.

    PubMed

    Machida, Chiyoko; Nakagawa, Ayami; Kojima, Shoko; Takahashi, Hiro; Machida, Yasunori

    2015-01-01

    Leaf primordia are born around meristem-containing stem cells at shoot apices, grow along three axes (proximal-distal, adaxial-abaxial, medial-lateral), and develop into flat symmetric leaves with adaxial-abaxial polarity. Axis development and polarity specification of Arabidopsis leaves require a network of genes for transcription factor-like proteins and small RNAs. Here, we summarize present understandings of adaxial-specific genes, ASYMMETRIC LEAVES1 (AS1) and AS2. Their complex (AS1-AS2) functions in the regulation of the proximal-distal leaf length by directly repressing class 1 KNOX homeobox genes (BP, KNAT2) that are expressed in the meristem periphery below leaf primordia. Adaxial-abaxial polarity specification involves antagonistic interaction of adaxial and abaxial genes including AS1 and AS2 for the development of two respective domains. AS1-AS2 directly represses the abaxial gene ETTIN/AUXIN RESPONSE FACTOR3 (ETT/ARF3) and indirectly represses ETT/ARF3 and ARF4 through tasiR-ARF. Modifier mutations have been identified that abolish adaxialization and enhance the defect in the proximal-distal patterning in as1 and as2. AS1-AS2 and its modifiers synergistically repress both ARFs and class 1 KNOXs. Repression of ARFs is critical for establishing adaxial-abaxial polarity. On the other hand, abaxial factors KANADI1 (KAN1) and KAN2 directly repress AS2 expression. These data delineate a molecular framework for antagonistic gene interactions among adaxial factors, AS1, AS2, and their modifiers, and the abaxial factors ARFs as key regulators in the establishment of adaxial-abaxial polarity. Possible AS1-AS2 epigenetic repression and activities downstream of ARFs are discussed.

  10. Iloprost drug delivery during infant conventional and high-frequency oscillatory ventilation.

    PubMed

    DiBlasi, Robert M; Crotwell, Dave N; Shen, Shuijie; Zheng, Jiang; Fink, James B; Yung, Delphine

    2016-03-01

    Iloprost is a selective pulmonary vasodilator approved for inhalation by the Food and Drug Administration. Iloprost has been increasingly used in the management of critically ill neonates with hypoxic lung disease. This in vitro study was designed to test the hypothesis that aerosol drug delivery could be effectively administered to infants with both conventional ventilation and high-frequency oscillatory ventilation (HFOV). A neonatal test lung model configured with newborn lung mechanics was ventilated with a conventional ventilator and an HFOV with standard settings. A vibrating-mesh nebulizer was placed (1) proximal to the patient airway in the inspiratory limb between the humidifier probe and patient wye (conventional) as well as between the vent circuit and the endotracheal tube (ETT) for HFOV and (2) between the ventilator and humidifier (distal). Iloprost was nebulized in three separate runs using three new nebulizers in each of the circuit locations. A collecting filter was placed at the distal end of the ETT for each trial. Iloprost was quantified using high-performance liquid chromatography. The percentage of nominal dose delivered was greater with the nebulizer placed proximal to the airway for conventional ventilation (10.74% ± 2%) and HFOV (29% ± 2%) than with it placed in the distal position (2.96% ± 0.2% vs. 0.96% ± 0.8%, respectively; P < 0.05). Drug delivery in proximal position was nearly threefold greater during HFOV than during conventional ventilation. In conclusion, iloprost drug delivery was best achieved when the nebulizer was placed proximal to the patient airway during neonatal mechanical ventilation. Drug delivery appears to be more efficient during HFOV than during conventional ventilation.

  11. Iloprost drug delivery during infant conventional and high-frequency oscillatory ventilation.

    PubMed

    DiBlasi, Robert M; Crotwell, Dave N; Shen, Shuijie; Zheng, Jiang; Fink, James B; Yung, Delphine

    2016-03-01

    Iloprost is a selective pulmonary vasodilator approved for inhalation by the Food and Drug Administration. Iloprost has been increasingly used in the management of critically ill neonates with hypoxic lung disease. This in vitro study was designed to test the hypothesis that aerosol drug delivery could be effectively administered to infants with both conventional ventilation and high-frequency oscillatory ventilation (HFOV). A neonatal test lung model configured with newborn lung mechanics was ventilated with a conventional ventilator and an HFOV with standard settings. A vibrating-mesh nebulizer was placed (1) proximal to the patient airway in the inspiratory limb between the humidifier probe and patient wye (conventional) as well as between the vent circuit and the endotracheal tube (ETT) for HFOV and (2) between the ventilator and humidifier (distal). Iloprost was nebulized in three separate runs using three new nebulizers in each of the circuit locations. A collecting filter was placed at the distal end of the ETT for each trial. Iloprost was quantified using high-performance liquid chromatography. The percentage of nominal dose delivered was greater with the nebulizer placed proximal to the airway for conventional ventilation (10.74% ± 2%) and HFOV (29% ± 2%) than with it placed in the distal position (2.96% ± 0.2% vs. 0.96% ± 0.8%, respectively; P < 0.05). Drug delivery in proximal position was nearly threefold greater during HFOV than during conventional ventilation. In conclusion, iloprost drug delivery was best achieved when the nebulizer was placed proximal to the patient airway during neonatal mechanical ventilation. Drug delivery appears to be more efficient during HFOV than during conventional ventilation. PMID:27162615

  12. Electronic Topological Transition in Ag2Te at High-pressure

    PubMed Central

    Zhang, Yuhang; Li, Yan; Ma, Yanmei; Li, Yuwei; Li, Guanghui; Shao, Xuecheng; Wang, Hui; Cui, Tian; Wang, Xin; Zhu, Pinwen

    2015-01-01

    Recently, Ag2Te was experimentally confirmed to be a 3D topological insulator (TI) at ambient pressure. However, the high-pressure behaviors and properties of Ag2Te were rarely reported. Here, a pressure-induced electronic topological transition (ETT) is firstly found in Ag2Te at 1.8 GPa. Before ETT, the positive pressure coefficient of bulk band-gap, which is firstly found in TIs family, is found by both first-principle calculations and in situ high-pressure resistivity measurements. The electrical resistivity obtained at room temperature shows a maximum at 1.8 GPa, which is nearly 3.3 times to that at ambient pressure. This result indicates that the best bulk insulating character and topological nature in Ag2Te can be obtained at this pressure. Furthermore, the high-pressure structural behavior of Ag2Te has been investigated by in situ high-pressure synchrotron powder X-ray diffraction technique up to 33.0 GPa. The accurate pressure-induced phase transition sequence is firstly determined as P21/c → Cmca → Pnma. It is worth noting that the reported isostructural P21/c phase is not existed, and the reported structure of Cmca phase is corrected by CALYPSO methodology. The second high-pressure structure, a long puzzle to previous reports, is determined as Pnma phase. A pressure-induced metallization in Ag2Te is confirmed by the results of temperature-dependent resistivity measurements. PMID:26419707

  13. Antimony and arsenic biogeochemistry in the western Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Cutter, Gregory A.; Cutter, Lynda S.; Featherstone, Alison M.; Lohrenz, Steven E.

    The subtropical to equatorial Atlantic Ocean provides a unique regime in which one can examine the biogeochemical cycles of antimony and arsenic. In particular, this region is strongly affected by inputs from the Amazon River and dust from North Africa at the surface, and horizontal transport at depth from high-latitude northern (e.g., North Atlantic Deep Water) and southern waters (e.g., Antarctic Bottom and Intermediate Waters). As a part of the 1996 Intergovernmental Oceanographic Commission's Contaminant Baseline Survey, data for dissolved As(III+V), As(III), mono- and dimethyl arsenic, Sb(III+V), Sb(III), and monomethyl antimony were obtained at six vertical profile stations and 44 sites along the 11,000 km transect from Montevideo, Uruguay, to Bridgetown, Barbados. The arsenic results were similar to those in other oceans, with moderate surface depletion, deep-water enrichment, a predominance of arsenate (>85% As(V)), and methylated arsenic species and As(III) in surface waters that are likely a result of phytoplankton conversions to mitigate arsenate "stress" (toxicity). Perhaps the most significant discovery in the arsenic results was the extremely low concentrations in the Amazon Plume (as low as 9.8 nmol/l) that appear to extend for considerable distances offshore in the equatorial region. The very low concentration of inorganic arsenic in the Amazon River (2.8 nmol/l; about half those in most rivers) is probably the result of intense iron oxyhydroxide scavenging. Dissolved antimony was also primarily in the pentavalent state (>95% antimonate), but Sb(III) and monomethyl antimony were only detected in surface waters and displayed no correlations with biotic tracers such as nutrients and chlorophyll a. Unlike As(III+V)'s nutrient-type vertical profiles, Sb(III+V) displayed surface maxima and decreased into the deep waters, exhibiting the behavior of a scavenged element with a strong atmospheric input. While surface water Sb had a slight correlation with

  14. Quantitative Antimony Speciation in Shooting-Range Soils by EXAFS Spectroscopy

    SciTech Connect

    Scheinost,A.; Rossberg, A.; Vantelon, D.; Xifra, I.; Kretzschmar, R.; Leuz, A.; Funke, H.; Johnson, C.

    2006-01-01

    The Sb speciation in soil samples from Swiss shooting ranges was determined using Sb K-edge X-ray absorption spectroscopy (XAS) and advanced statistical data analysis methods (iterative transformation factor analysis, ITFA). The XAS analysis was supported by a spectral data set of 13 Sb minerals and 4 sorption complexes. In spite of a high variability in geology, soil pH (3.1-7.5), Sb concentrations (1000-17,000 mg/kg) and shooting-range history, only two Sb species were identified. In the first species, Sb is surrounded solely by other Sb atoms at radial distances of 2.90, 3.35, 4.30 and 4.51 Angstroms, indicative of metallic Sb(0). While part of this Sb(0) may be hosted by unweathered bullet fragments consisting of PbSb alloy, Pb L{sub III}-edge XAS of the soil with the highest fraction (0.75) of Sb(0) showed no metallic Pb, but only Pb{sup 2+} bound to soil organic matter. This suggests a preferential oxidation of Pb in the alloy, driven by the higher standard reduction potential of Sb. In the second species, Sb is coordinated to 6 O-atoms at a distance of 1.98 Angstroms, indicative of Sb(V). This oxidation state is further supported by an edge energy of 30,496-30,497 eV for the soil samples with <10% Sb(0). Iron atoms at radial distances of 3.10 and 3.56 Angstroms from Sb atoms are in line with edge-sharing and bidentate corner-sharing linkages between Sb(O,OH)6 and Fe(O,OH)6 octahedra. While similar structural units exist in tripuhyite, the absence of Sb neighbors contradicts formation of this Fe antimonate. Hence the second species most likely consists of inner-sphere sorption complexes on Fe oxides, with edge and corner-sharing configuration occurring simultaneously. This pentavalent Sb species was present in all samples, suggesting that it is the prevailing species after weathering of metallic Sb(0) in oxic soils. No indication of Sb(III) was found.

  15. GEMAS: prediction of solid-solution phase partitioning coefficients (Kd) for oxoanions and boric acid in soils using mid-infrared diffuse reflectance spectroscopy.

    PubMed

    Janik, Leslie J; Forrester, Sean T; Soriano-Disla, José M; Kirby, Jason K; McLaughlin, Michael J; Reimann, Clemens

    2015-02-01

    The authors' aim was to develop rapid and inexpensive regression models for the prediction of partitioning coefficients (Kd), defined as the ratio of the total or surface-bound metal/metalloid concentration of the solid phase to the total concentration in the solution phase. Values of Kd were measured for boric acid (B[OH]3(0)) and selected added soluble oxoanions: molybdate (MoO4(2-)), antimonate (Sb[OH](6-)), selenate (SeO4(2-)), tellurate (TeO4(2-)) and vanadate (VO4(3-)). Models were developed using approximately 500 spectrally representative soils of the Geochemical Mapping of Agricultural Soils of Europe (GEMAS) program. These calibration soils represented the major properties of the entire 4813 soils of the GEMAS project. Multiple linear regression (MLR) from soil properties, partial least-squares regression (PLSR) using mid-infrared diffuse reflectance Fourier-transformed (DRIFT) spectra, and models using DRIFT spectra plus analytical pH values (DRIFT + pH), were compared with predicted log K(d + 1) values. Apart from selenate (R(2)  = 0.43), the DRIFT + pH calibrations resulted in marginally better models to predict log K(d + 1) values (R(2)  = 0.62-0.79), compared with those from PSLR-DRIFT (R(2)  = 0.61-0.72) and MLR (R(2)  = 0.54-0.79). The DRIFT + pH calibrations were applied to the prediction of log K(d + 1) values in the remaining 4313 soils. An example map of predicted log K(d + 1) values for added soluble MoO4(2-) in soils across Europe is presented. The DRIFT + pH PLSR models provided a rapid and inexpensive tool to assess the risk of mobility and potential availability of boric acid and selected oxoanions in European soils. For these models to be used in the prediction of log K(d + 1) values in soils globally, additional research will be needed to determine if soil variability is accounted on the calibration.

  16. [Evaluation of clinical and laboratory findings of adult visceral leishmaniasis cases].

    PubMed

    Ural, Serap; Kaptan, Figen; Sezak, Nurbanu; El, Sibel; Örmen, Bahar; Türker, Nesrin; Demirdal, Tuna; Vardar, İlknur; Özkan Çayıröz, Pınar; Çakalağaoğlu, Fulya

    2015-10-01

    either meglumine antimonate (Glucantime(®), 20 mg/kg/day, intramuscularly for 28 days) or liposomal amphotericin B (3 mg/kg/day, intravenously for the first 5 days, then on 14(th) and 21(st) days) according to the availability of drugs. During one year follow-up period all of the patients improved and no recurrence was seen in any patient. In conclusion, among adult patients with fever uncontrolled within 2-week course of ampiric antibiotic treatment without any infectious focus or malignancy, VL should also be considered. PMID:26649416

  17. Transformation/dissolution examination of antimony and antimony compounds with speciation of the transformation/dissolution solutions.

    PubMed

    Skeaff, James M; Beaudoin, Robert; Wang, Ruiping; Joyce, Barry

    2013-01-01

    Speciation is held to be a key factor in controlling the ecotoxicity of metals in solution. Using the United Nations transformation/dissolution protocol (T/DP) for metals and sparingly soluble metal compounds, we have examined the transformation/dissolution (T/D) characteristics in terms of the concentrations of total dissolved Sb at pH 6 and 8.5 in 1, 10, and 100 mg/L loadings over 7 d as well as the concentrations of Sb(III) and Sb(V) at the 1 mg/L loadings over 28 d, of sodium hexahydroxoantimonate (NaSb(OH)(6)), antimony metal (Sb), antimony trioxide (Sb(2) O(3)), antimony sulfide (Sb(2) S(3)), sodium antimonate (NaSbO(3)), antimony tris(ethylene glycolate) (Sb(2) (C(2) H(4) O(2) )(3)), antimony trichloride (SbCl(3)), antimony triacetate (Sb(CH(3) COO)(3)), and antimony pentoxide (Sb(2) O(5) ). We also measured the concentrations of the dissolved Sb(III) and Sb(V) species at the 1 mg/L loadings. Because of complexing, the trivalent organic Sb compounds exhibited little or no oxidation of Sb(III) to Sb(V). However, oxidation of Sb(III) to Sb(V) was evident for the trivalent inorganic Sb compounds. Conversely, with pentavalent Sb compounds, there was no reduction of Sb(V) to Sb(III). Based on the percentage of Sb in the compound dissolved or metal reacted at 28 d and 1 mg/L loadings, the solubility rankings at pH 6 are NaSb(OH)(6)  > Sb(CH(3) COO)(3)  > Sb metal > Sb(2) (C(2) H(4) O(2))(3)  > Sb(2) S(3)  > Sb(2) O(3)  > NaSbO(3)  ≈ SbCl(3)  > Sb(2) O(5). For pH 8.5 the order is NaSb(OH)(6)  > Sb(CH(3) COO)(3)  > Sb metal > Sb(2) (C(2) H(4) O(2) )(3)  > SbCl(3)  > Sb(2) O(3)  > Sb(2) S(3)  > NaSbO(3)  > Sb(2) O(5) . We provide worked examples of how the T/D data have been used to derive hazard classification proposals for Sb metal and these selected compounds for submission to the European Chemicals Agency under the Registration, Evaluation, Authorization and Restriction of CHemicals (REACH

  18. Removal of Radioactive Nuclides by Multi-Functional Microcapsules Enclosing Inorganic Ion-Exchangers and Organic Extractants

    SciTech Connect

    Mimura, H.; Akiba, K.; Onodera, Y.

    2002-02-26

    The microcapsules enclosing two kinds of functional materials, inorganic ion-exchangers and organic extractants, were prepared by taking advantage of the high immobilization ability of alginate gel polymer. The fine powders of inorganic ion-exchanger and oil drops of extractant were kneaded with sodium alginate (NaALG) solution and the kneaded sol readily gelled in a salt solution of CaCl2, BaCl2 or HCl to form spherical gel particles. The uptake properties of various nuclides, 137Cs, 85Sr, 60Co, 88Y, 152Eu and 241Am, for thirty-four specimens of microcapsules in the presence of 10-1-10-4 M HNO3 were evaluated by the batch method. The distribution coefficient (Kd) of Cs+ above 103 cm3/g was obtained for the microcapsules enclosing CuFC or AMP. The Kd of Sr2+ around 102 cm3/g was obtained for the microcapsules containing clinoptilolite, antimonic acid, zeolite A, zeolite X or titanic acid. The microcapsules enclosing DEHPA exhibited relatively large Kd values of trivalent metal ions above 103 cm3/g; for example, the Kd values of Cs+, Sr2+, Co2+, Y3+, Eu3+ and Am3+ for a favorable microcapsule (CuFC/clinoptilolite/DEHPA/CaALG) were 1.1x104, 7.5x10, 1.1x10, 1.0x104, 1.4x104, 3.4x103 cm3/g, respectively. The uptake rates of Cs+, Y3+, Eu3+ and Am3+ for this microcapsule were rather fast; the uptake percentage above 90% was obtained after 19 h-shaking and the uptake equilibrium was attained within 1 d. The AMP/CaALG exhibited high uptake ability for Cs+ even after irradiation of 188 kGy, and DEHPA/CaALG microcapsule had similar Kd values of Cs+, Sr2+, Co2+, Y3+, Eu3+ and Am3+ ions before and after irradiation. The microcapsules with various shapes such as spherical, columnar, fibrous and filmy forms were easily prepared by changing the way of dipping kneaded sol into gelling salt solution. The microcapsules enclosing inorganic ion-exchangers and extractants have a potential possibility for the simultaneous removal of various radioactive nuclides from waste solutions.

  19. Photochemical ozone creation potentials for oxygenated volatile organic compounds: sensitivity to variations in kinetic and mechanistic parameters

    NASA Astrophysics Data System (ADS)

    Jenkin, Michael E.; Hayman, Garry D.

    , and new schemes are incorporated for dimethoxy methane (CH 3OCH 2OCH 3) and dimethyl carbonate (CH 3OC(O)OCH 3), which are proposed fuel additives. New or updated POCP values are calculated for all 37 oxygenated VOCs and, where applicable, these are compared with the previous POCP values and reported Maximum Incremental Reactivity (MIR) values.

  20. Searching for trans ethyl methyl ether in Orion KL⋆

    NASA Astrophysics Data System (ADS)

    Tercero, B.; Cernicharo, J.; López, A.; Brouillet, N.; Kolesniková, L.; Motiyenko, R. A.; Margulès, L.; Alonso, J. L.; Guillemin, J.-C.

    2015-10-01

    We report on the tentative detection of trans ethyl methyl ether (tEME), t-CH3CH2OCH3, through the identification of a large number of rotational lines from each one of the spin states of the molecule towards Orion KL. We also search for gauche-trans-n-propanol, Gt-n-CH3CH2CH2OH, an isomer of tEME in the same source. We have identified lines of both species in the IRAM 30 m line survey and in the ALMA Science Verification data. We have obtained ALMA maps to establish the spatial distribution of these species. Whereas tEME mainly arises from the compact ridge component of Orion, Gt-n-propanol appears at the emission peak of ethanol (south hot core). The derived column densities of these species at the location of their emission peaks are ≤(4.0 ± 0.8) × 1015 cm-2 and ≤(1.0 ± 0.2) × 1015 cm-2 for tEME and Gt-n-propanol, respectively. The rotational temperature is ~100 K for both molecules. We also provide maps of CH3OCOH, CH3CH2OCOH, CH3OCH3, CH3OH, and CH3CH2OH to compare the distribution of these organic saturated O-bearing species containing methyl and ethyl groups in this region. Abundance ratios of related species and upper limits to the abundances of non-detected ethers are provided. We derive an abundance ratio N(CH3OCH3)/N(tEME) ≥ 150 in the compact ridge of Orion. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2011.0.00009.SV. ALMA is a partnership of ESO (representing its member states), NSF (USA), and NINS (Japan) with NRC (Canada), NSC, and ASIAA (Taiwan), and KASI (Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, AUI/NRAO, and NAOJ. This work was also based on observations carried out with the IRAM 30-m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain).Appendix A is available in electronic form at http://www.aanda.org

  1. Thermal Decomposition Mechanisms of Lignin Model Compounds: From Phenol to Vanillin

    NASA Astrophysics Data System (ADS)

    Scheer, Adam Michael

    Lignin is a complex, aromatic polymer abundant in cellulosic biomass (trees, switchgrass etc.). Thermochemical breakdown of lignin for liquid fuel production results in undesirable polycyclic aromatic hydrocarbons that lead to tar and soot byproducts. The fundamental chemistry governing these processes is not well understood. We have studied the unimolecular thermal decomposition mechanisms of aromatic lignin model compounds using a miniature SiC tubular reactor. Products are detected and characterized using time-of-flight mass spectrometry with both single photon (118.2 nm; 10.487 eV) and 1 + 1 resonance-enhanced multiphoton ionization (REMPI) as well as matrix isolation infrared spectroscopy. Gas exiting the heated reactor (300 K--1600 K) is subject to a free expansion after a residence time of approximately 100 micros. The expansion into vacuum rapidly cools the gas mixture and allows the detection of radicals and other highly reactive intermediates. By understanding the unimolecular fragmentation patterns of phenol (C6H5OH), anisole (C6H 5OCH3) and benzaldehyde (C6H5CHO), the more complicated thermocracking processes of the catechols (HO-C 6H4-OH), methoxyphenols (HO-C6H4-OCH 3) and hydroxybenzaldehydes (HO-C6H4-CHO) can be interpreted. These studies have resulted in a predictive model that allows the interpretation of vanillin, a complex phenolic ether containing methoxy, hydroxy and aldehyde functional groups. This model will serve as a guide for the pyrolyses of larger systems including lignin monomers such as coniferyl alcohol. The pyrolysis mechanisms of the dimethoxybenzenes (H3C-C 6H4-OCH3) and syringol, a hydroxydimethoxybenzene have also been studied. These results will aid in the understanding of the thermal fragmentation of sinapyl alcohol, the most complex lignin monomer. In addition to the model compound work, pyrolyisis of biomass has been studied via the pulsed laser ablation of poplar wood. With the REMPI scheme, aromatic lignin decomposition

  2. Effects of methanol on the thermodynamics of iron(III) [tetrakis(pentafluorophenyl)]porphyrin chloride dissociation and the creation of catalytically active species for the epoxidation of cyclooctene.

    PubMed

    Stephenson, Ned A; Bell, Alexis T

    2006-07-10

    In a previous study, the authors showed that iron(III) [tetrakis(pentafluorophenyl)]porphyrin chloride [(F20TPP)FeCl] is catalytically inactive for cyclooctene epoxidation by hydrogen peroxide in acetonitrile but is catalytically active if the solvent contains methanol. It was suggested that the precursor to the active species is (F20TPP)Fe(OCH3) in methanol-containing solvents. The present study was aimed at evaluating this hypothesis. (F20TPP)Fe(OCH3) was synthesized and characterized by 1H NMR but was found to be inactive in both acetonitrile and methanol. Further investigation of the interactions of (F20TPP)FeCl with methanol in acetonitrile/methanol mixtures was then carried out using NMR. Two species, characterized by 1H NMR resonances at 82 and 65 ppm, were observed. The first resonance is attributed to the beta-pyrrole protons on molecularly dissolved (F20TPP)FeCl, whereas the second is attributed to beta-pyrrole protons of [(F20TPP)Fe]+ cations that are stabilized by coordination with a molecule of methanol, viz., [(F20TPP)Fe(CH3OH)]+. The relative concentration of [(F20TPP)Fe(CH3OH)]+ increases as the fraction of methanol in the solvent increases, suggesting that methanol facilitates the dissociation of (F20TPP)FeCl into cations and anions. A thermodynamic model of the dissociation is proposed and found to describe successfully the experimental observation over a range of solvent compositions, porphyrin concentrations, and temperatures. UV-visible spectroscopy was also used to validate the developed model. In addition, the observed rate constant for cyclooctene epoxidation was found to be proportional to the concentration of [(F20TPP)Fe(CH3OH)]+ calculated using the thermodynamic model, suggesting that this intermediate is a precursor to the species that catalyzes olefin epoxidation. The catalytic activity of [(F20TPP)Fe(CH3OH)]+ was further confirmed through experiments in which (F20TPP)Fe(OCH3) dissolved in methanol was reacted with HCl(aq). This

  3. Schiff base mediated sol-gel polymerization

    SciTech Connect

    Lindquist, D.A.; Harrison, C.M.; Williams, B.; Morris, R.D.

    1996-12-31

    Formation of a Schiff base imine by reacting a primary amine with either an aldehyde or ketone was initiated by an aluminum compound acting as a Lewis acid catalyst. The water byproduct of the reaction then was used as an in situ reagent for subsequent hydrolysis and sol-gel condensation of the aluminum species. These reactions yielded a gel network containing the entrained Schiff base. Two examples of this synthetic approach are described with two different aluminum catalyst/reagents: a diethylaluminum diethylphosphate ester [(CH{sub 3}CH{sub 2}){sub 2}Al-O-P(O)(OCH{sub 2}CH{sub 3}){sub 2}] and triethyl aluminum [Al(CH{sub 3}CH{sub 2}){sub 3}]. Anhydrous ammonia and acetone were used as the Schiff base precursors.

  4. Synthesis and Fluorescence Properties of Eu(3+), Tb(3+) Complexes with Schiff Base Derivatives.

    PubMed

    Liu, Yanhong; Kong, Weihua; Yang, Zehui; Dai, Ming; Shi, Ling; Guo, Dongcai

    2016-03-01

    Novel Schiff base ligands derived from N'-benzylidene-benzohydrazide (substituted by -H, -CH3, -OCH3, -Cl) and 2-chloro-N-phenylacetamide were synthesized. The solid complexes of rare earth (Eu, Tb) nitrate with these Schiff base ligands were synthesized and characterized by elemental analysis, EDTA titrimetric analysis, thermal analysis, infrared spectra and UV-Vis spectra analysis. The fluorescence properties of rare earth (Eu, Tb) complexes in solid were studied. Under the excitation of ultraviolet light, these complexes exhibited characteristic emission of europium and terbium ions. The results showed that the ligand favored energy transfer to the emitting energy of Eu and Tb ions. Effects of different ligands on the fluorescence intensity of rare earth (Eu, Tb) complexes had been discussed. The electrochemical properties of rare earth (Eu, Tb) complexes were also investigated.

  5. Dispersive Stabilization of Liquid Crystal-in-Water with Acrylamide Copolymer/Surfactant Mixture: Nematic Curvilinear Aligned Phase Composite Film.

    PubMed

    Park; Lee

    1999-11-01

    The effect of nonionic surfactant, (H(OCH(2)-CH(2))(8)-OC(6)H(4)-C(9)H(19)), on the dispersion stabilization of liquid crystal (LC)-in-water with acrylamide copolymer containing the related nonylphenyl groups was studied. It was observed that the addition of nonionic surfactant increases the stability of LC dispersions and improves the electrooptical properties of the nematic curvilinear aligned phase (NCAP) composite film. On the basis of the surface tension, reduced viscosity, cloud point, and coalescence time measurements, it was proposed that formation of an integrated structure induced by interactions between hydrophobic groups in the polymer chains is probably important to fabrication of a polymer composite film made of LC and polymer matrix. Copyright 1999 Academic Press.

  6. Synthesis and properties of salicyladehyde salicyhydrazone derivatives and their europium complexes.

    PubMed

    Meng, Defen; Liu, Fen; Lian, Xiaomei; Yang, Zehui; Guo, Dongcai

    2014-11-01

    Four novel salicyladehyde salicyhydrazone derivatives and their corresponding europium (Eu(3+)) complexes were synthesized and characterized. The formulas of the complexes were [EuL(a-d)(NO3)2](NO3) · H2O. The investigatoin of fluoresence properties of the Eu(3+) complexes showed that the salicyladehyde salicyhydrazone derivatives were efficient sensitizers for the fluoresence of Eu(3+) ions. The fluorescence intensity of the complex substituted by methyl (-CH3) was the strongest among all the Eu(3+) complexes. The exploration of the electrochemical properties of the Eu(3+) complexes showed that the introduction of electron-donating groups methyl and methoxyl (-CH3 and -OCH3) could increase the oxidation potential and the highest occupied molecular orbital (HOMO) energy level of the Eu(3+) complex; however, the results of introduction of electron-withdrawing group were just opposite.

  7. Syntheses and spectroscopy of germanium and tin compounds with biorelevant ligands

    NASA Astrophysics Data System (ADS)

    Breitinger, D. K.; Grützner, T.; Wick, H.; Schimmer, O.; Eschelbach, H.

    1997-06-01

    The germanium and tin compounds diaquabis(glycolato)germanium(IV) Ge(OCH 2COO) 2(H 2O) 2 ( 1), bis(thioglycolato)-, bis(thiolactato)-, and bis(thiohydracrylato)-germanium(IV) Ge(SJCOO) 2 (J = CH 2 ( 2), CH(CH 3) ( 3), CH 2CH 2 ( 4)), as well as the tetrakis(alkylthioglycolato)tetrels Tt(SCH 2COOR) 4 (Tt = Ge ( 5, 6) and Sn ( 7, 8); R = Me, i-Pr, respectively), under study for their antimutagenic properties, were studied by vibrational spectrometry. Some of the skeletal vibrations of the octahedral 1 and otherwise tetrahedral compounds were assigned. Data from 1H- and 13C- NMR spectra and from mass spectra are also reported.

  8. p-type transparent conducting oxides

    NASA Astrophysics Data System (ADS)

    Sheng, Su; Fang, Guojia; Li, Chun; Xu, Sheng; Zhao, Xingzhong

    2006-06-01

    The recent advance of p-type transparent conductive oxide thin films is reviewed. The focus is on p-type transparent oxide semiconductors CuAlO2, CuGaO2, CuInO2, SrCu2O2, and LaCuOCh (Ch = chalcogen). These materials and related device applications are then shown as examples. Room temperature operation of current injection emission from ultraviolet light-emitting diodes based on p-SCO/n-ZnO p-n junctions has been demonstrated. This changed with the discovery of p-type transparent conducting oxides, thereby opening up the possibility for all-oxide transparent electronics.

  9. Radical scavenging of white tea and its flavonoid constituents by electron paramagnetic resonance (EPR) spectroscopy.

    PubMed

    Azman, Nurul A M; Peiró, Sara; Fajarí, Lluís; Julià, Luis; Almajano, Maria Pilar

    2014-06-25

    White tea (WT) presents high levels of catechins, which are known to reduce oxidative stress. WT is the least processed tea, unfermented and prepared only from very young tea leaves. The subject of this paper is the use of the spin trap method and electron paramagnetic resonance (EPR) spectroscopy as the analytical tool to measure, for the first time, the radical scavenging activity of WT and its major catechin components, epicatechin (EC), epicatechin-3-gallate (ECG), epigallocatechin (EGC), and epigallocatechin-3-gallate (EGCG), against the methoxy radical, using ferulic acid as antioxidant pattern. The antioxidant activity has been measured by the decrease of the intensity of the spectral bands of the adduct DMPO-OCH3 in the EPR with the amount of antioxidant in the reactive mixture. Tea leaves and buds were extracted with waterless methanol. It has been proved that tea compounds with more antiradical activity against methoxy radical are those with the gallate group, EGCG and ECG. PMID:24885813

  10. Fluorescence quenching in an organic donor-acceptor dyad: a first principles study.

    PubMed

    Körzdörfer, T; Tretiak, S; Kümmel, S

    2009-07-21

    Perylene bisimide and triphenyl diamine are prototypical organic dyes frequently used in organic solar cells and light emitting devices. Recent Forster-resonant-energy-transfer experiments on a bridged organic dyad consisting of triphenyl diamine as an energy-donor and perylene bisimide as an energy-acceptor revealed a strong fluorescence quenching on the perylene bisimide. This quenching is absent in a solution of free donors and acceptors and thus attributed to the presence of the saturated CH(2)O(CH(2))(12)-bridge. We investigate the cause of the fluorescence quenching as well as the special role of the covalently bound bridge by means of time dependent density functional theory and molecular dynamics. The conformational dynamics of the bridged system leads to a charge transfer process between donor and acceptor that causes the acceptor fluorescence quenching. PMID:19624200

  11. Synthesis and biological evaluation of 1-phenyl-1,2,3,4-dihydroisoquinoline compounds as tubulin polymerization inhibitors.

    PubMed

    Zheng, Can-Hui; Chen, Jun; Liu, Jia; Zhou, Xiao-Tian; Liu, Na; Shi, Duo; Huang, Jing-Jing; Lv, Jia-Guo; Zhu, Ju; Zhou, You-Jun

    2012-06-01

    A series of 1-phenyl-3,4-dihydroisoquinoline derivatives and several 1-phenyl-1,2,3,4-tetrahydroisoquinoline, 1-phenyl-isoquinoline analogues were synthesized, and their cytotoxicity and tubulin polymerization inhibitory activity were evaluated. The 1-phenyl-3,4-dihydroisoquinoline compounds were found to be potential tubulin polymerization inhibitors. Compound 5n, bearing a 3'-OH and 4'-OCH(3) substituted 1-phenyl B-ring, was shown to confer optimal bioactivity. The single-crystal structure of 5n was further determined by X-ray diffraction, and the binding mode of 5n to tubulin was obtained by molecular docking, which can explain the structure-activity relationships. The studies presented here provide a new structural type for the development of novel antitumor agents.

  12. Induced cholesteric systems based on some cyano derivatives as host phases

    NASA Astrophysics Data System (ADS)

    Shkolnikova, Natalya I.; Kutulya, Lidiya A.; Vashchenko, V. V.; Fedoryako, A. P.; Lapanik, V. I.; Posledovich, N. R.

    2002-12-01

    Macroscopical properties of some induced cholesteric compositions based on 4-pentyl-4'-cyano derivatives of biphenyl and phenylcyclohexane as host phases have been investigated. The series of N-arylidene derivatives of (S)-1-phenylethylamine with varied both rigid moiety of the N-arylidene fragment and terminal substituent was used as chiral dopants. The influence of the chiral dopant molecular structure as well as of physical properties of the host phases used on the helical twisting power, the temperature dependence of the induced helical pitch and the N* mesophase thermal stability has been characterized. It has been concluded that the distinctions in properties of the LC systems containing the OCH2 and COO linking groups are caused by their different conformational states.

  13. Extraction processes and solvents for recovery of cesium, strontium, rare earth elements, technetium and actinides from liquid radioactive waste

    DOEpatents

    Zaitsev, Boris N.; Esimantovskiy, Vyacheslav M.; Lazarev, Leonard N.; Dzekun, Evgeniy G.; Romanovskiy, Valeriy N.; Todd, Terry A.; Brewer, Ken N.; Herbst, Ronald S.; Law, Jack D.

    2001-01-01

    Cesium and strontium are extracted from aqueous acidic radioactive waste containing rare earth elements, technetium and actinides, by contacting the waste with a composition of a complex organoboron compound and polyethylene glycol in an organofluorine diluent mixture. In a preferred embodiment the complex organoboron compound is chlorinated cobalt dicarbollide, the polyethylene glycol has the formula RC.sub.6 H.sub.4 (OCH.sub.2 CH.sub.2).sub.n OH, and the organofluorine diluent is a mixture of bis-tetrafluoropropyl ether of diethylene glycol with at least one of bis-tetrafluoropropyl ether of ethylene glycol and bis-tetrafluoropropyl formal. The rare earths, technetium and the actinides (especially uranium, plutonium and americium), are extracted from the aqueous phase using a phosphine oxide in a hydrocarbon diluent, and reextracted from the resulting organic phase into an aqueous phase by using a suitable strip reagent.

  14. Synthesis and In-vitro Cytotoxicity Assessment of N-(5-(Benzylthio)-1,3,4- thiadiazol-2-yl)-2-(4-(trifluoromethyl)phenyl)acetamide with Potential Anticancer Activity

    PubMed Central

    Aliabadi, Alireza; Hasanvand, Zaman; Kiani, Amir; Mirabdali, Seyed Saber

    2013-01-01

    Cancer is the second leading cause of death in the world. Despite advances in the diagnosis and treatment, overall survival of patients still remains poor. Hence, there is an urgent need for development of new anticancer agents. Considering promising biological activity of 1,3,4-thiadiazole derivatives, in the present study, synthesis and cytotoxicity assessment of new derivatives of this ring was done. All synthesized compounds were characterized by NMR, IR and MS spectroscopic methods. Obtained data from MTT assay showed that all compounds 3a- 3l had better anticancer activity against MDA(breast cancer) compared to PC3(prostate cancer) and U87(Glioblastoma). Compound 3 g with m-OCH3 moiety on the phenyl ring was the most potent one in this series with IC50 = 9 μM against MDA breast cell line in comparison with imatinib (IC50 = 20 μM) as reference drug. PMID:24523748

  15. Formaldehyde mediated proton-transport catalysis in the ketene-water radical cation CH2C(O)OH2+

    NASA Astrophysics Data System (ADS)

    Lee, Richard; Ruttink, Paul J. A.; Burgers, Peter C.; Terlouw, Johan K.

    2006-09-01

    Previous studies have shown that the solitary ketene-water ion CH2C(O)OH2+ (1) does not isomerize into CH2C(OH)2+ (2), its more stable hydrogen shift isomer. Tandem mass spectrometry based collision experiments reveal that this isomerization does take place in the CH2O loss from low-energy 1,3-dihydroxyacetone ions (HOCH2)2CO+. A mechanistic analysis using the CBS-QB3 model chemistry shows that such molecular ions rearrange into hydrogen-bridged radical cations [CH2C(O)O(H)-H...OCH2]+ in which the CH2O molecule catalyzes the transformation 1 --> 2 prior to dissociation. The barrier for the unassisted reaction, 29 kcal mol-1, is reduced to a mere 0.6 kcal mol-1 for the catalysed transformation. Formaldehyde is an efficient catalyst because its proton affinity meets the criterion for facile proton-transport catalysis.

  16. The use of a vanadium species as a catalyst in photoinduced water oxidation.

    PubMed

    Santoni, Marie-Pierre; La Ganga, Giuseppina; Mollica Nardo, Viviana; Natali, Mirco; Puntoriero, Fausto; Scandola, Franco; Campagna, Sebastiano

    2014-06-11

    The first water oxidation catalyst containing only vanadium atoms as metal centers is reported. The compound is the mixed-valence [(V(IV)5V(V)1)O7(OCH3)12](-) species, 1. Photoinduced water oxidation catalyzed by 1, in the presence of Ru(bpy)3(2+) (bpy = 2,2'-bipyridine) and Na2S2O8, in acetonitrile/aqueous phosphate buffer takes place with a quantum yield of 0.20. A hole scavenging reaction between the photochemically generated Ru(bpy)3(3+) and 1 occurs with a bimolecular rate constant of 2.5 × 10(8) M(-1) s(-1). The time-resolved formation of the oxidized molecular catalyst 1(+) in bimolecular reactions is also evidenced for the first time by transient absorption spectroscopy. This result opens the way to the use of less expensive vanadium clusters as water oxidation catalysts in artificial photosynthesis schemes.

  17. α-Tocopherol impact on oxy-radical induced free radical decomposition of DMSO: Spin trapping EPR and theoretical studies

    NASA Astrophysics Data System (ADS)

    Jerzykiewicz, Maria; Ćwieląg-Piasecka, Irmina; Witwicki, Maciej; Jezierski, Adam

    2011-05-01

    EPR spin trapping and theoretical methods such as density functional theory (DFT) as well as combined DFT and quadratic configuration interaction approach (DFT/QCISD) were used to identify the radicals produced in the reaction of oxy-radicals and dimethyl sulfoxide (DMSO) in the presence and absence of α-tocopherol. Additionally, the mixtures of α-tocopherol with linolenic acid and glyceryl trilinoleate as well as bioglycerols (glycerol fractions from biodiesel production) were tested. α-Tocopherol inhibited oxidation of the main decomposition product of DMSO, •CH 3 to •OCH 3 but did not prevent the transformation process of N-t-butyl- α-phenylnitrone (PBN) into 2-methyl-2-nitrosopropane (MNP). Theoretical investigations confirmed the structures of proposed spin adducts and allowed to correlate the EPR parameters observed in the experiment with the spin adducts electronic structure.

  18. Process for treating radioactive waste

    SciTech Connect

    Chino, K.; Kawamura, F.; Kikuchi, M.; Yusa, H.

    1982-11-30

    N-beta-(Aminoethyl)-gamma-aminopropyltrimethoxysilane (NH2(CH2)2NH(CH2)3SI(OCH3)3) as a silane coupling agent and SiO(2 -x)(ONa)x/2(OH)x/2 as colloidal silica are mixed into a radioactive liquid waste containing sodium sulfate as a main component, coming from a boiling water-type, nuclear power plant as an effluent. The resulting mixed radioactive liquid waste is supplied into a vessel provided with a rotating shaft with blades. The rotating shaft is revolved while heating the radioactive liquid waste in the vessel, thereby making the radioactive liquid waste into powder. The resulting powder containing the silane coupling agent and the colloidal silica is shaped into pellets by a pelletizer. The pellets having a low hygroscopicity and a high strength are obtained.

  19. Luminescence from Vacuum-Ultraviolet-Irradiated Cosmic Ice Analogs and Residues

    NASA Technical Reports Server (NTRS)

    Gudipati, Murthy S.; Dworkin, Jason P.; Chillier, Xavier D. F.; Allamandola, Louis J.

    2003-01-01

    Here we report a study of the optical luminescent properties for a variety of vacuum-ultraviolet (VUV)- irradiated cosmic ice analogs and the complex organic residues produced. Detailed results are presented for the irradiated, mixed molecular ice: H2O:CH3OH:NH3:CO (100:50:1:1), a realistic representation for an interstellar/precometary ice that reproduces all the salient infrared spectral features associated with interstellar ices. The irradiated ices and the room-temperature residues resulting from this energetic processing have remarkable photoluminescent properties in the visible (520-570 nm). The luminescence dependence on temperature, thermal cycling, and VUV exposure is described. It is suggested that this type of luminescent behavior might be applicable to solar system and interstellar observations and processes for various astronomical objects with an ice heritage. Some examples include grain temperature determination and vaporization rates, nebula radiation balance, albedo values, color analysis, and biomarker identification.

  20. 5-Methoxysalicylic Acid Matrix for Ganglioside Analysis with Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Lee, Dongkun; Cha, Sangwon

    2015-03-01

    In this note, we report that high quality ganglioside profiles with minimal loss of sialic acid residues can be obtained in the positive ion mode by using a 5-methoxysalicylic acid (MSA) matrix for matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). Our results showed that MSA produced much less sialic acid losses from gangliosides than DHB, although MSA and DHB are differ only by their functional groups at their 5-positions (-OH for DHB and -OCH3 for MSA). Furthermore, our data also demonstrated that addition of an alkali metal additive was effective for simplifying ganglioside profiles, but not necessary for stabilizing glycosidic bonds of gangliosides if MSA was used as a matrix. This suggests that MALDI MS with MSA has a potential to gain additional benefits from the positive-ion mode analyses without losing performance in ganglioside profiling.