bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel saturated red‐emitting poly(p‐phenylenevinylene) copolymers with narrow‐band‐gap units of 2,1,3‐benzothiadiazole synthesized by a palladium‐catalyzed Stille coupling reaction
Authors: Li Xianzhen , Zhang Yong , Yang Renqiang , Huang Jian , Yang Wei , Cao Yong
Published: April 2005

Novel poly(p‐phenylenevinylene) (PPV) copolymers derived from 1‐methoxy‐4‐octyloxyphenylene (MOP), 2,1,3‐benzothiadiazole (BT), and trans‐1,2‐bis(tributylstannyl)ethylene were first prepared by a palladium‐catalyzed Stille coupling reaction. The feed ratios of MOP to BT were 99.5:0.5, 99:1, 95:5, 85:15, 70:30, and 50:50. An efficient energy transfer from the 2‐methoxy‐5‐octyloxy‐p‐phenylenevinylene segment to the narrow‐band‐gap units was observed. The poly(2‐methoxy‐5‐octyloxy‐p‐phenylenevinylene‐2,1,3‐benzothiadiazolevinylene) copolymers emitted deep red light. The maximum electroluminescence emission of these PPV copolymers occurred at 659–724 nm and was accompanied by gradual redshifting with an increasing BT concentration. The photophysical properties were examined in comparison with those of copolymers based on BT and fluorene or N‐alkylcarbazole doped with the same BT concentration in the copolymer main chain. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2325‐2336, 2005
Improved thermosets obtained from cycloaliphatic epoxy resins and γ‐butyrolactone with lanthanide triflates as initiators. I. Study of curing by differential scanning calorimetry and Fourier transform infrared
Authors: Mas Cristina , Mantecón Ana , Serra Angels , Ramis Xavier , Salla Josep Maria
Published: April 2005

3,4‐Epoxycyclohexylmethyl 3,4‐epoxycyclohexane carboxylate was cured with different proportions of γ‐butyrolactone with lanthanum, samarium, and ytterbium triflates as catalysts. The curing was studied with differential scanning calorimetry (DSC) and Fourier transform infrared in the attenuated‐total‐reflection mode (FTIR/ATR). FTIR/ATR was used to monitor the competitive reactive processes and to quantify the evolution of the epoxide, lactone, and intermediate spiroorthoester groups. The glass‐transition temperature of the crosslinked materials was high and increased when the proportion of lactone decreased. The kinetics were studied with DSC experiments and were analyzed with isoconversional procedures. The differences in the reactivities of the systems were related to the Lewis acidity of the lanthanide salt used as the initiator. An increase in the proportion of lactone produced an increase in the reaction rate. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2337‐2347, 2005
Quantification of imidacloprid toxicity to avocado thrips, Scirtothrips perseae Nakahara (Thysanoptera: Thripidae), using a combined bioassay and ELISA approach
Authors: Byrne Frank J , Toscano Nick C , Urena Anthony A , Morse Joseph G
Published: April 2005

A competitive ELISA (enzyme‐linked immunosorbent assay) technique was evaluated for quantifying titres of imidacloprid in homogenates of leaf discs sampled from avocado plants treated with systemic applications of imidacloprid 240 g litre−1SC (Admire®). Matrix effects were evident with undiluted leaf tissue homogenates, but these were effectively eliminated by dilution of homogenates in water. In a field trial conducted in a commercial nursery, there was an excellent correlation between imidacloprid residues within leaves and avocado thrips (Scirtothrips perseae Nakahara) mortality. However, with subsequent sampling over a 2‐month period, the relationship between mortality and apparent imidacloprid concentration became less robust, suggesting that the material was being degraded within the plant to non‐toxic metabolites. Nevertheless, assessments of thrips mortality on leaves that had been recently treated with imidacloprid established a lower threshold of activity for imidacloprid residues of 6 ng cm−2 leaf. Limitations on the use of ELISA to quantify the impact of systemic insecticides on pest populations are discussed. Copyright © 2005 Society of Chemical Industry
Simultaneous analysis of twenty‐one glucocorticoids in equine plasma by liquid chromatography/tandem mass spectrometry
Authors: Luo Y. , Uboh C. E. , Soma L. R. , Guan F. Y. , Rudy J. A. , Tsang D. S.
Published: April 2005

A method for the simultaneous separation, identification, quantification and confirmation of the presence of 21 glucocorticoids (GCC) in equine plasma by liquid chromatography coupled with triple stage quadrupole tandem mass spectrometry (LC/TSQ‐MS/MS) is described. Plasma sample augmented with the 21 GCC was extracted with methyltert‐butyl ether (MTBE) and analyzed by positive electrospray ionization. Desoxymetasone or dichlorisone acetate was used as the internal standard (IS). Quantification was performed by IS calibration. For each drug, one major product ion was chosen and used for screening for that drug. Analyte confirmation was performed by using the three most intense product ions formed from the precursor ion and the corresponding mass ratios. The recovery of the 21 GCC when spiked into blank plasma at 5 ng/mL was 45–200% with coefficient of variation (CV) from 0.3–18%. The limit of detection (LOD) and that of quantification (LOQ) for most of the analytes were 50–100 pg/mL and 1 ng/mL, respectively, whereas that of confirmation (LOC) was 100–300 pg/mL depending on the analyte. Intra‐ and inter‐day precisions expressed as CV for quantification of 1 and 10 ng/mL was 1.0–17%, and 0.51–19%, respectively, and the accuracy was from 84–110%. The linear concentration range for quantification was 0.1–100 ng/mL (r2 > 0.997). Estimated measurement uncertainty was from 11–37%. This study was undertaken to develop a method for simultaneous screening, identification, quantification and confirmation of these agents in post‐race equine plasma samples. The method has been successfully applied to screening of a large number of plasma samples obtained from racehorses in competition and in pharmacokinetic studies of dexamethasone in the horse and concurrent changes in endogenous GCC, hydrocortisone and cortisone. The method is simple, sensitive, selective and reliably reproducible. Copyright © 2005 John Wiley & Sons, Ltd.
Denaturation of metalloproteins with EDTA to facilitate enzymatic digestion and mass fingerprinting
Authors: Janecki Dariusz J. , Reilly James P.
Published: April 2005

Metal ions bound to a protein often stabilize tertiary and/or quaternary structure. Consequently, the digestion of metalloproteins that precedes analysis by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry is frequently incomplete. It is demonstrated that ethylenediaminetetraacetic acid (EDTA) successfully destabilizes metalloprotein structure and thereby facilitates tryptic digestion and protein identification. Copyright © 2005 John Wiley & Sons, Ltd.
Vertical gradients of δ15N and δ18O in soil atmospheric N2O—temporal dynamics in a sandy soil
Authors: Van Groenigen Jan Willem , Zwart Kor B. , Harris David , van Kessel Chris
Published: April 2005

The greenhouse gas nitrous oxide (N2O) can be both formed and consumed by microbial processes in the soil. As these processes fractionate strongly in favour of 14N and 16O, δ15N and δ18O gradients of N2O in the soil profile may elucidate patterns of N2O formation, consumption or emission to the atmosphere. We present the first in situ data of such gradients over time for a mesic typic Haplaquod seeded with potatoes (Solanum tuberosum L.). On two adjacent fields in 2002 and 2003, topsoil N2O fluxes were measured and the soil atmosphere was regularly sampled for N2O concentrations, δ15N and δ18O signatures of N2O at depths of 18, 48 and 90 cm during ∼400 days. During the entire sampling period, the N2O concentrations were the highest and the δ15N signatures the lowest in the subsoil (48 or 90 cm depth) as compared with the topsoil, indicating production of N2O in the subsoil. For δ15N, differences greater than 30‰ between topsoil and subsoil on the same date were regularly observed. The highest N2O concentration of 100385 μL m−3 at 90 cm depth on 1 July 2003, was preceded by the lowest δ15N value of −43.5‰ one week earlier. This was followed by a 150‐day general decrease of N2O concentrations at 90 cm depth to 1723 μL m−3 and a simultaneous enrichment of δ15N to +7.1‰, mostly without a significant topsoil flux. There was a negative logarithmic relationship between N2O concentration at 90 cm depth and its δ15N signature. This relationship indicated a δ15N signature of −40 to −45‰ during the production of N2O in the subsoil, and a subsequent enrichment during the consumption of N2O. We conclude that the isotopic signature of the N2O topsoil flux is the result of various processes of consumption and production at different depths in the soil profile. It is therefore not a reliable estimator for the overall δ15N signature of N2O in the soil atmosphere, nor for indirect losses of N2O to the environment. Therefore, these findings will pose a further challenge to ongoing efforts to draw up a global isotopic budget for N2O. Copyright © 2005 John Wiley & Sons, Ltd.
B5C5 Anionic Molecules Trapped in a Solid Matrix: The Crystal and Electronic Structures of LaBC
Authors: Babizhetskyy Volodymyr , Mattausch Hansjürgen , Gautier Régis , Bauer Josef , Halet Jean‐François , Simon Arndt
Published: April 2005

The crystal structure of LaBC, prepared by arc melting of mixtures of the pure elements and subsequent annealing at 1000 °C, has been determined from single crystal X‐ray diffraction data. It crystallizes in a new structure type with the orthorhombic space group P212121 (a = 8.646(1), b = 8.691(1), c = 12.479(1) Å, R1 = 0.021 (wR2 = 0.057) for 4437 reflections with Io > 2σ(Io)). Its structural arrangement consists of a three‐dimensional framework of lanthanum atoms resulting from the stacking of slightly corrugated two‐dimensional square nets, leading to voids filled with B5C5 finite chains. Isostructural compounds are formed with Ce, Pr, Nd and Sm. Structural and theoretical analysis suggests a formulation as (La5)8.3+(B5C5)8.3−. Density functional theory calculations reveal significant covalent bonding between the metal atom framework and the boron carbon chains.
Mg1−xRhB ‐ a New Boridometallide with 2D Polyanion
Authors: Alekseeva A. M. , Abakumov A. M. , Leithe‐Jasper A. , Schnelle W. , Prots Yu. , Hadermann J. , Van Tendeloo G. , Antipov E. V. , Grin Yuri
Published: April 2005

A new magnesium boridometallide Mg1−xRhB has been prepared by reaction of the elements in an argon‐filled sealed Ta container at 1323 K. A narrow homogeneity range (0.05 ≤ × ≤ 0.08) was established by X‐ray powder diffraction data and EDXS investigations. The crystal structure of Mg1−xRhB (x = 0.05) was solved using single‐crystal X‐ray diffraction data and confirmed by electron diffraction and high‐resolution electron microscopy (space group P6222, a = 5.2394(1), c = 9.4251(3) Å, Z = 6, 228 reflections, 19 variables, R(F) = 0.025). The structure can be topologically described as a derivative of the CeCo3B2 structure type where the positions in the cobalt layers are occupied by magnesium and rhodium atoms in an ordered manner. From the bonding analysis using the electron localization function, Mg1−xRhB is described as a two‐dimensional [RhB] polyanion with embedded magnesium cations. The material is weakly diamagnetic and reveals metallic electrical conductivity.
Coordination Polymers that Contain Accessible Metal Centres ‐ Synthesis and Structure of a Nickel Cluster Connected Porphyrin Network
Authors: Kempe Rhett
Published: April 2005

A porous nickel porphyrin coordination polymer was prepared via solvothermal synthesis starting from 5,10,15,20‐tetrakis‐(4‐carboxyphenyl)‐21H,23H‐porphine and Ni(NO3)2·6H2O. The product was characterized by single crystal X‐ray diffraction and elemental analysis. Space group: ${\rm P}{\bar 1}$, triclinic, a = 9.817(2), b = 15.465(3), c = 17.928(3) Å, α = 94.14(1), β = 103.30(1), γ = 97.77(1)°, V = 2609.4(9) Å3, Z = 2, R = 0.079, wR2 (all data) = 0.225. The structure determination revealed the porous coordination polymer:

a) to be a nickel cluster connected porphyrin 3‐D network, which can provide up to six coordination sites per cluster unit after removal of the labile bound water ligands and

b) to have two types of channels of the dimensions [atom to atom distances] of 18 × 6 and 13 × 6Å2.
Tri‐n‐Butyl‐Phosphan‐Silber(I)‐Komplexe mit Carboxylat‐, Troponolat‐ bzw. N‐Hydroxyphthalimid‐Teilstrukturen; Synthese und Verwendung als Spin‐On‐Precursoren
Authors: Jakob A. , Schmidt H. , Walfort B. , Rheinwald G. , Frühauf S. , Schulz S. , Gessner T. , Lang H.
Published: April 2005

Tri‐n‐Butyl‐Phosphane Silver(I) Complexes with Carboxylate‐, Tropolonate‐ or N‐Hydroxyphthalimide Building Blocks; Synthesis and their Use as Spin‐on Precursors

Treatment of AgNO3 (1) with one equivalent of HX (2a, X = trop; 2b, X = phthal; trop = troponolate; phthal = N‐hydroxy‐phthalimide anion) in presence of NEt3 affords the silver(I) salts [AgX] (3a, X = trop; 3b, X = phthal) in quantitative yield. When instead of 2a and 2b oxalic acid (4a) or quadratic acid (1,2‐dihydroxycyclobutene‐3,4‐dione) (4b) are reacted with 1 under similar reaction conditions, then the corresponding disilver salts [Ag2E] (5a, E = ox; 5b, E = quad; ox = oxalate; quad = quadratic acid dianion) are accessible in excellent yield.

The reaction of 3 and 5 with m equivalents of nBu3P (6) produces the phosphane silver(I) complexes (nBu3P)mAgX (m = 1: 7a, X = trop; 7b, X = phthal; m = 2: 8a, X = trop; 8b, X = phthal) and (nBu3P)mAg‐E‐Ag(PnBu3)m (m = 1: 9a, E = ox; 9b, E = quad; m = 2: 10a, E = ox; 10b, E = quad; m = 3: 11a, E = ox; 11b, E = quad), which can be isolated after appropriate work‐up as colourless (9–11), yellow (7a, 8a) or red‐purple (7b, 8b) species.

The solid‐state structures of 7b and 9a are reported. Complex 7b exists of two (nBu3P)Ag(phthal) units in which the oxygen atoms of the N‐hydroxyphthalimide anions are μ‐bridging both silver atoms. The thus formed 4‐membered Ag2O2 cycle is planar and the silver atoms show the coordination number 3. Complex 9a exhibits a planar dinuclear structure with the anticipated oxalate building block in a μ‐1,2,3,4 bridging mode. As typical for 7b also for 9a a tricoordinated silver(I) ion is present, whereby the phosphanes act as neutral capping ligands.

The thermal behaviour of selected species (7b, 8b, 9a, 10a, 11a and 11b) was studied by applying thermogravimetry. The decomposition of the latter complexes starts between 100–160 °C and is completed in the region of 350–400 °C. One – four decomposition steps are typical. The decomposition of 9a was studied in detail. Elimination of nBu3P occurs at first, while loss of CO2 from in‐situ generated [Ag2ox] gives elemental silver. For that reason, 9a was used as spin‐on precursor in the deposition of silver on TiN‐coated oxidized silicon wafers. REM studies showed that closed and homogeneous silver layers were formed. The resistivity was determined to 3.4 μΩcm.
Synthese und Kristallstrukturen von PrSe2 und NdSe2
Authors: Doert Thomas , Graf Christian
Published: April 2005

Synthesis and Crystal Structures of PrSe2 and NdSe2

Crystals of PrSe2 and NdSe2 can be made by chemical transport reactions starting from pre‐annealed powders (800 – 600 °C, 2 weeks, I2 as transport agent). Both compounds adopt the CeSe2‐type structure. They crystallize in the monoclinic space group P21/a with four formula units and lattice parameters of a = 8.396(2) Å, b = 4.184(1) Å, c = 8.431(2) Å, and β = 90.08(4)° (PrSe2) and a = 8.352(2) Å, b = 4.164(1) Å, c = 8.412(2) Å, and β = 90.00(3)° (NdSe2), respectively. The crystal structures consist of puckered double layers of Ln and Se atoms and planar Se layers stacked in an alternating way along the crystallographic c axis. The Se atoms of the planar layers form diselenide dumb‐bells , which are arranged in a herringbone‐like pattern. The Se–Se distances in the Se‐dimers are 2.467(1) Å in PrSe2 and 2.476(1) Å in NdSe2.
Silver‐Hydrogen Interactions in Crystalline Silver Dodecahydrododecaborates
Authors: Volkov Oleg , Hu Chunhua , Paetzold Peter
Published: April 2005

The syntheses and structures of the three silver dodecahydrododecaborates: AmAgB12H12, Am(AgL)2Ag(B12H12)2, and (AgL)2B12H12 (Am = benzyltriethylammonium, NBzlEt3; L = acetonitrile) are presented. The silver cations are connected to the B12H122− cages by single or double hydrogen bonds to give chains, layers, or a three‐dimensional connection, respectively. For comparison, it is also reported on the syntheses and structures of the dodecabromododecaborates (AgL′)2B12Br12 (L′ = acetone) and Am2B12Br12.
M4N2Te3 (M = La – Nd): Die ersten Nitridtelluride der dreiwertigen Lanthanide
Authors: Lissner Falk , Schleid Thomas
Published: April 2005

M4N2Te3 (M = La – Nd): The First Nitride Tellurides with Trivalent Lanthanides

The oxidation of the light lanthanides (M = La – Nd) with tellurium and sodium azide (NaN3) in the presence of the corresponding trichlorides (MCl3) yields the first nitride tellurides of the lanthanides with the composition M4N2Te3 when appropriate molar ratios of the reactants are used. Additional sodium chloride (NaCl) as a flux secures complete and fast reactions (7 d) at 900 °C in evacuated silica tubes as well as the formation of black single crystals. The orthorhombic crystal structure (Pnma, Z = 4) was determined from single crystal X‐ray diffraction data for La4N2Te3 (a = 746.58(6), b = 1184.16(9), c = 1160.71(9) pm), Ce4N2Te3 (a = 739.26(6), b = 1169.73(9), c = 1148.04(9) pm), Pr4N2Te3 (a = 734.75(6), b = 1163.82(9), c = 1139.53(9) pm), and Nd4N2Te3 (a = 730.61(6), b = 1159.57(9), c = 1131.46(9) pm). Three crystallographically different M3+ cations are present, two of them (M1 and M2) reside in sixfold coordination of two N3− and four Te2− anions forming trigonal prisms. The third cation (M3) is coordinated by two N3− and five Te2− in the shape of a monocapped trigonal prism. However, the main feature of the crystal structure comprises N3−‐centred (M3+)4 tetrahedra which are connected via trans‐edges to build up one‐dimensional infinite chains {[NM]3+} (e = edge‐sharing). These chains, caused by a significant tilting of the single tetrahedra relative to each other, are not stretched to ideal linearity, so a doubled repetition period compared to the single one (≈ two edge lengths of a tetrahedron) is necessary. They get bundled along [010] like a hexagonal rod packing and held together by two crystallographically different Te2− anions. Further motifs for the interconnection of [NM4]9+ tetrahedra in crystal structures of nitride chalcogenides and halides of the rare‐earth elements (M = Sc, Y, La; Ce – Lu) with ratios of N : M = 1 : 2 are presented and discussed for comparison.
Zum chemischen Transport und zur Kristallstruktur von Seltenerdarsenaten(V)
Authors: Schmidt Marcus , Müller Ulf , Cardoso Gil Raul , Milke Edgar , Binnewies Michael
Published: April 2005

Chemical Vapour Transport and Crystal Structure of Rare‐Earth Arsenates(V)

Crystals of a series of rare‐earth arsenates(V) REAsO4 (RE = Sc, Y, La–Nd, Sm–Lu) and mixed crystals of selected composition were obtained by endothermic chemical transport with TeCl4 as a transport medium. The gaseous phase of the transport reaction has been studied using mass spectrometry. The crystal structures of LaAsO4 and NdAsO4 (space group: P21/n (No. 14); Pearson symbol: mP24) as well as of HoAsO4 and ScAsO4 (space group: I41/amd (No. 141); Pearson symbol: tI24) were refined from single crystal X‐ray diffraction data.
NH4Cd(H2O)2(BP2O8)·0.72H2O: a New Borophosphate with Abnormal Structure Changes Caused by Hydrogen Interactions
Authors: Ge Ming‐Hui , Liu Wei , Chen Hao‐Hong , Li Man‐Rong , Yang Xin‐Xin , Zhao Jing‐Tai
Published: April 2005

A new borophosphate NH4Cd(H2O)2(BP2O8)·0.72H2O has been synthesized under mild hydrothermal conditions. The crystal structure was characterized by single crystal X‐ray diffraction method. Crystal Data: Hexagonal, P65 (No.176), a = 9.6978(16) Å, c = 16.026(4) Å, V = 1305.3(4) Å3, Z = 6, R1 = 0.0256 and wR2 = 0.0665 for 1409 observed unique reflections and 146 variables. The structure is characterized by corner‐sharing PO4 and BO4 tetrahedra, leading to infinite helical {[BP2O8]3−} ribbons, which are connected by CdO4(H2O)2 coordination octahedra. Nevertheless, the structure reveals significant difference from its other ammonium containing analogues with respect to the occupations of NH4+ and the metal cation. The abnormal changes of the unit cells comparing with cadmium borophosphates with other counter cations were presumably due to the anisotropic hydrogen bonds along the c‐axis or on the ab‐plane. Its UV‐Vis fluorescence property was investigated for the first time.
Polar [NbOCl3]2n and [NbOX4−]n (X = Cl, Br) Chains in the Structures of NbOCl3 and the Thallium‐Halogenooxoniobates Tl[NbOCl4] and Tl[NbOBr4] ‐ Synthesis, Crystal Structures and Optical Second Harmonic Generation
Authors: Beck Johannes , Bordinhão Jairo
Published: April 2005

The reactions of thallium(I)halides TlCl and TlBr with Nb2O5 and NbCl5, and NbBr5, respectively, under the conditions for chemical vapour transport in closed evacuated ampoules in a temperature gradient from 350 °C to 300 °C give yellow Tl[NbOCl4] and red Tl[NbOBr4] in 50 % yield. The crystal structures (Tl[NbOCl4]: orthorhombic, Pbca, a = 1259.9(1), b = 791.9(1), c = 1506.9(1) pm; Tl[NbOBr4]: monoclinic, C2, a = 1304.9(3), b = 402.7(3), c = 770.6(3) pm, β = 108.150(3)) are built of linear chains of associated [NbOX4−]n (X = Cl, Br) ions and of Tl+ ions located between the chains. The individual square‐pyramidal [NbOX4−] ions are linked by asymmetric O···Nb–O bridges. The Tl+ ions are coordinated by halogen atoms in form of strongly distorted square antiprisms for X = Cl, and in form of cubes for X = Br. The two structures are not isotypic even though they are made up of analogous building units. The centrosymmetry of the Tl[NbOCl4] structure causes the polar chains to run in opposite directions. The structure of Tl[NbOBr4] is acentric and the polar [NbOBr4−]n chains all point into the same direction. An optical second harmonic generation experiment confirmed the recently performed redetermination of the structure of NbOCl3 (Stroebele, Meyer 2002). NbOCl3 crystallizes acentric with analogously polar [Nb2O2Cl6]n chains.
[ClBe{MeN(CH2CH2NMe2)2}]+Cl− ‐ ein kationischer Berylliumkomplex
Authors: Neumüller Bernhard , Dehnicke Kurt
Published: April 2005

[ClBe{MeN(CH2CH2NMe2)2}]+Cl− ‐ a Cationic Beryllium Complex

Beryllium(II)chloride reacts with N,N,N′,N″,N″‐pentamethyldiethylentriamine (PMDETA) in dichloromethane suspension to give the cationic complex [ClBe{MeN(CH2CH2NMe2)2}]+Cl− (1), which crystallizes with one equivalent of CH2Cl2. 1 is characterized by IR spectroscopy and by X‐ray single crystal structure analysis. 1·CH2Cl2: Space group P21, Z = 2, lattice dimensions at 193 K: a = 696.2(1), b = 1107.7(2), c = 1113.4(1) pm, β = 98.20(1)°, R1 = 0.0355.
GPS Receiver Operations on the Disaster Monitoring Constellation Satellites
Authors: Ebinuma Takuji , Rooney Elizabeth , Gleason Scott , Unwin Martin
Published: April 2005

The Disaster Monitoring Constellation (DMC) is an international Earth observation programme to provide a rapid global remote sensing service for the monitoring and mitigation of natural and man-made disasters. Although the Global Positioning System (GPS) was originally designed for terrestrial and air applications, satellite operations have benefited greatly from the use of on-board GPS receivers. This paper describes the GPS receiver operations on the DMC satellites, performance analysis, lessons learned, and upgrades planned for the future.
Parental preference for one-stage versus two-stage surgical repair for children with congenital heart disease
Authors: Chang Ruey-Kang R. , Joyce James J.
Published: April 2005

Background:Little is known regarding parental preference for a one-stage complete repair versus a two-staged approach with initial palliation, followed by repair, of the congenital cardiac malformation.Methods:We interviewed 103 parents of healthy children referred to a clinic for pediatric cardiology. Participants were presented with a hypothetical scenario in which their children had a cardiac lesion requiring surgery. The surgery could be performed either by means of one-stage complete repair, or using a two-stage approach, with palliation first followed by complete repair a year later. The mortality rate for the one-stage repair was set at 5%. Participants were asked to choose between the one- and two-stage approaches, with differing mortality rates for the two-stage approach. The scenarios included options when the two-stage combined mortality rate was lower than the one-stage mortality, and the first stage mortality rate was at 1% and 3%, and when the two-stage combined mortality rate was the same as that for one-stage mortality, these being set at 1% and 3%.Results:When the two-stage combined mortality rate was lower than that of the one-stage repair, participants were more likely to choose the two-stage approach if the first stage mortality rate was 1% as compared to 3% (57% and 44%, respectively, p = 0.04). When the two-stage combined mortality rate was the same as the one-stage approach, participants choosing the two-stage approach when the mortality rate was set at 1%, and when it was raised to 3%, were not significantly different (42% and 34%, respectively, p = 0.24). When the combined two-stage mortality was the same as that set for one-stage repair, participants with no insurance were less likely to choose the two-stage approach than those covered by insurance (p = 0.03).Conclusions:In the chosen scenarios, when the mortality for a two-stage combined approach is the same as that for one-staged repair, more parents choose the one-staged repair. If the two-stage combined mortality is lower than that for one-staged repair, parents are more likely to choose the two-stage repair if the mortality for the first stage is lower. When the mortality rates for the one-stage and two-stage approaches are the same, people without insurance are more likely to choose one-staged repair.
Anomalous left coronary artery from the non-adjacent sinus of the pulmonary trunk
Authors: Kannan Bhava R. J. , Anil Sivadasan R. , Krishna Kumar R.
Published: April 2005

We report a rare variant of anomalous origin of the left coronary artery from the non-adjacent sinus of the pulmonary trunk. The patient also had the right coronary artery arising from the non-facing sinus of the aorta.
Large pericardial effusions of inflammatory origin in childhood
Authors: Mok Geoffrey Chi Fung , Menahem Samuel
Published: April 2005

Objectives:Our aim was to review the clinical records from children with large pericardial effusions of inflammatory origin presenting to a tertiary referral centre over the last 21 years, with emphasis on their clinical presentation, management and outcome.Background:The common identifiable causes of pericardial effusion in children include prior cardiac surgery, bacterial pericarditis, malignancy, and connective tissue disorders. In a significant number of children, however, despite extensive investigation, it is not possible to identify a clear aetiology. A viral cause is often considered, though rarely confirmed. The clinical course of such large idiopathic pericardial effusions in children has not been extensively reported.Methods and results:We reviewed retrospectively the records of all patients seen between 1981 and 2001 with large pericardial effusions of inflammatory origin requiring drainage, excluding the effusions related to cardiac surgery or malignancy. We found 31 patients fulfilling our criterions for study. They could be divided into three groups, with 15 patients having no specific identifiable aetiology despite extensive investigation, 12 patients having evidence of bacterial pericarditis, and four with a probable immunologic disorder. Fever was present in only eight patients (53%) in the idiopathic group. All patients in the other groups had fever. Except for fever and the resultant tachycardia, it was not possible to distinguish on clinical grounds, nor on the presence or otherwise of cardiac tamponade, between those with idiopathic aetiology and those with bacterial infection. Of the patients with presumed bacterial pericarditis, five (42%) had both positive blood and pericardial fluid cultures, three (25%) had positive blood cultures, while a further three patients (25%) had only positive pericardial fluid cultures. All patients required drainage of the pericardial effusion, either under echocardiographic guidance or surgically. None of the patients died. The hospital stay was significantly shorter for those with idiopathic as opposed to bacterial pericarditis. Of those with an idiopathic aetiology, six required readmission due to recurrence of the pericardial effusion, with four patients requiring further surgical drainage. No patients required readmission with a bacterial or immunologic aetiology. No patient developed constrictive pericarditis after a median follow-up of 22 months.Conclusion:Patients with large idiopathic pericardial effusion had relatively few constitutional symptoms as compared with their gross echocardiographic findings. Those with bacterial pericarditis had more urgent need for treatment. Patients with pericardial effusion of inflammatory origin, when treated appropriately, had an excellent outcome with no mortality or development of constrictive pericarditis.
Normal patterns of flow in the superior caval, hepatic and pulmonary veins as measured using Doppler echocardiography during childhood
Authors: Ayabakan Canan , Özkutlu Süheyla
Published: April 2005

To date, no reference values have been provided for right and left atrial filling in normal children. The aim of our study, therefore, was to characterize measurements of superior caval, hepatic, and pulmonary venous flow using Doppler echocardiography in a large group of normal children to reflect the effects of age, body mass index, sex, heart rate and respiration.

Doppler echocardiographic examinations of the superior caval, hepatic and pulmonary veins were performed during inspiration and expiration in 72 healthy children with a mean age of 6.73 ± 5.10 years. The subjects were segregated into four age groups, namely infants <2 years, preschool children between the ages of 2 and 7 years, children of school age between 7 and 11 years, and adolescents older than 11 years.

Age has significant effect on the systolic and reverse atrial flows within the superior caval vein (p < 0.05). No change in the Doppler velocities was observed related to body mass index or sex. All peak systolic velocities decreased significantly during expiration (p < 0.05). This decrease was most prominent in the hepatic vein (26%), but less remarkable in the superior caval vein (5.7%) and the pulmonary veins (3.9%). During expiration, the peak diastolic flow in the superior caval and the hepatic veins decreased, while the reverse atrial flow in the hepatic vein increased (p < 0.05). Pulmonary venous velocities were similar in all age groups (p > 0.05). Except for the systolic pulmonary venous velocities, these parameters were not influenced by respiration (p > 0.05). The diastolic time, the interval between reverse atrial flow and ventricular systole reflected by the R wave on the electrocardiogram, and the interval between ventricular systole and diastolic flow, were negatively correlated with heart rate (p < 0.05; r = −0.35, −0.85, and −0.8 respectively), and positively correlated with age (p < 0.05; r = 0.3, 0.8, and 0.7 respectively). They were not influenced by respiration.

Our study provides data of the patterns and the normal ranges of velocities of superior caval, hepatic, and pulmonary venous flow in a series of normal children. The results can now be used for comparison with the patterns found in the setting of disease.
Constraining the components of the Kerguelen mantle plume: A Hf‐Pb‐Sr‐Nd isotopic study of picrites and high‐MgO basalts from the Kerguelen Archipelago
Authors: Doucet Sonia , Scoates James S. , Weis Dominique , Giret André
Published: April 2005

We report geochemical and Hf‐Pb‐Sr‐Nd isotopic analyses of a suite of picrites and associated high‐MgO volcanic rocks (6–17 wt.% MgO) from the Kerguelen Archipelago, which are rare compared to other oceanic islands, to better constrain the nature and the origin of components present in the Kerguelen mantle plume source. The Sr and Nd isotopic compositions of the transitional to mildly alkalic picrites and high‐MgO basalts closely match those of the 24 Ma mildly alkalic basalts from the Courbet Peninsula, whose compositions are considered to reflect the present geochemical expression of the enriched component of the Kerguelen mantle plume. However, linear trends in Pb isotopic compositions in the studied samples reflect involvement of a component with lower 206Pb/204Pb and 208Pb/204Pb than that inferred for the enriched Kerguelen plume. Contamination of the MgO‐rich magmas by the Kerguelen Plateau cannot account for the observed Hf‐Pb‐Sr‐Nd isotopic variations. Isotopic systematics in the picrites and the high‐MgO basalts are inconsistent with simple binary mixing between two distinct end‐members and indicate the presence of small‐scale heterogeneities within the Kerguelen plume itself as has been observed in other hot spot environments such as Hawaii and Iceland. The 34 to 26 Ma Kerguelen plume‐related basalts that formed when the archipelago was close to the ridge axis (∼50 to 250 km) show geochemical evidence for significant involvement of a Southeast Indian Ridge (SEIR)‐like source. In contrast, the 24–25 Ma mildly alkalic basalts from the eastern and southeastern parts of the archipelago, which erupted about 400 km away from the SEIR, and the picrites and high‐MgO basalts from this study show little or no contribution from a SEIR‐like component. Thus chemical interaction between the SEIR axis and the Kerguelen plume effectively ceased prior to 25 Ma.
Measurement of the Henry's law coefficient and first order loss rate of PAN in n‐octanol
Authors: Roberts James M.
Published: April 2005

The Henry's Law solubility and first order loss rates of PAN (peroxyacetic nitric anhydride, CH3C(O)OONO2) in a model non‐polar solvent, n‐octanol, were measured for a range of temperatures pertinent to the lower troposphere (273–298 °K). The solubility was found to be factors of 6 to 12 higher than those measured previously for pure water, ranging between 110 ± 7.5 M/atm at 273°K and 34 ± 1.7 M/atm at 298°K. The loss rates were found to vary from below 0.5 × 10−5 sec−1 at 273°K to 5.2 ± 1.9 × 10−5 sec−1 at 298°K. Several simple approaches were used to estimate that the uptake of PAN on organic aerosol has a negligible impact on ambient PAN concentrations.
Deterministic earthquake scenario for the Basel area: Simulating strong motions and site effects for Basel, Switzerland
Authors: Opršal Ivo , Fäh Donat , Mai P. Martin , Giardini Domenico
Published: April 2005

The Basel earthquake of 18 October 1356 is considered one of the most serious earthquakes in Europe in recent centuries (I0 = IX, M ≈ 6.5–6.9). In this paper we present ground motion simulations for earthquake scenarios for the city of Basel and its vicinity. The numerical modeling combines the finite extent pseudodynamic and kinematic source models with complex local structure in a two‐step hybrid three‐dimensional (3‐D) finite difference (FD) method. The synthetic seismograms are accurate in the frequency band 0–2.2 Hz. The 3‐D FD is a linear explicit displacement formulation using an irregular rectangular grid including topography. The finite extent rupture model is adjacent to the free surface because the fault has been recognized through trenching on the Reinach fault. We test two source models reminiscent of past earthquakes (the 1999 Athens and the 1989 Loma Prieta earthquake) to represent Mw ≈ 5.9 and Mw ≈ 6.5 events that occur approximately to the south of Basel. To compare the effect of the same wave field arriving at the site from other directions, we considered the same sources placed east and west of the city. The local structural model is determined from the area's recently established P and S wave velocity structure and includes topography. The selected earthquake scenarios show strong ground motion amplification with respect to a bedrock site, which is in contrast to previous 2‐D simulations for the same area. In particular, we found that the edge effects from the 3‐D structural model depend strongly on the position of the earthquake source within the modeling domain.
Effects of amantadine and budipine on antidepressant drug‐evoked changes in extracellular 5‐HT in the frontal cortex of freely moving rats
Authors: Owen Jenny C E , Whitton Peter S
Published: April 2005

Evidence has recently suggested that NMDA receptors may play a role in the aetiology and possible treatment of depression and that weak noncompetitive NMDA receptor antagonists such as amantadine can synergize with conventional antidepressants in a model of the illness.

To try to obtain a neurochemical rationale for these findings, we have studied the effects of acute and chronic administration of amantadine or the related drug budipine on cortical release of 5‐hydroxytryptamine (5‐HT) following the antidepressants reboxitine (REB), paroxetine (PAROX) and clomipramine (CLOM) in freely moving rats by using microdialysis.

Acute administration of amantadine (40 mg kg−1), budipine (10 mg kg−1), REB (10 mg kg−1), PAROX (10 mg kg−1) or CLOM (10 mg kg−1) all failed to significantly alter extracellular 5‐HT in the cortex. However, when either amantadine or budipine was administered 30 min prior to any of the three antidepressants, a significant rise in 5‐HT was observed.

For chronic studies, the effects of the drugs were studied at 4, 7, 14 and 21 days. Amantadine and budipine did not significantly alter extracellular 5‐HT at any time point. The three antidepressant drugs all elicited a gradual increase in 5‐HT, which became significant after 14 days and tended to plateau thereafter. When either amantadine (20 mg kg−1) or budipine (5 mg kg−1) was coadministered with any of the three antidepressants, two differences were seen compared with the effects of the antidepressants alone. Firstly, the time required for significant increases in cortical 5‐HT was reduced with elevated levels now being observed by 7 days. Secondly, the absolute magnitude of the increase in extracellular 5‐HT was markedly greater in these rats from day 7 until the end of the experiment.

If, as is widely considered, an increase in extracellular 5‐HT represents a critical step in the mechanism of action of antidepressants, these data suggest that combined treatment with clinically tolerated NMDA antagonists such as amantadine could reduce the delay in therapeutic onset of antidepressants as well as possibly enhance their efficacy.

British Journal of Pharmacology (2005) 145, 587–592. doi:10.1038/sj.bjp.0706188
The cardiovascular actions of anandamide: more targets?
Authors: Randall Michael D
Published: April 2005

British Journal of Pharmacology (2005) 145, 565–566. doi:10.1038/sj.bjp.0706234
A mean field approach for molecular simulations of fluid systems
Authors: Brancato Giuseppe , Di Nola Alfredo , Barone Vincenzo , Amadei Andrea
Published: April 2005

In this paper we introduce a mean field method for simulating complex molecular systems like liquids and solutions. Using well-established theoretical principles and models, we obtained a relatively simple approach which seems to provide a reliable description of the bulk molecular behavior of liquid water. Moreover, we have applied this approach to study simple solutes in solution, like sodium and chloride ions and acetone. Comparison with standard simulations, performed with periodic boundary conditions, shows that such a mean field method can reproduce the same structural and thermodynamical properties at low computational costs and represents a valid alternative for simulating solute-solvent systems, like solutions of large biomolecules.
Structure of dense hydrogen fluoride gas from neutron diffraction and molecular dynamics simulations
Authors: Kreitmeir Markus , Heusel Gerhard , Bertagnolli Helmut , Tödheide Klaus , Mundy Christopher J. , Cuello Gabriel J.
Published: April 2005

The gas phase of hydrogen fluoride has been investigated by neutron diffraction experiments at three different particle densities. All investigated states are within the liquid-gas coexistence region of hydrogen fluoride. From the obtained diffraction data we deduced information about the local structure of the gas phase, which consists of small agglomerates. This has been expected as liquid hydrogen fluoride forms the strongest hydrogen bonds known. Molecular dynamics simulations with a modified potential have been carried out for all experimentally investigated states. The results confirmed that the size of the formed agglomerates in the gas phase is growing with increasing density of the gas phase.
Determination of the Duration of Preoperative Smoking Cessation to Improve Wound Healing after Head and Neck Surgery
Authors: Kuri Michioki , Nakagawa Masashi , Tanaka Hideo , Hasuo Seiko , Kishi Yoshihiko
Published: April 2005

Background

Preoperative smoking cessation has been suggested to be effective in reducing various postoperative complications. However, the optimal duration of preoperative smoking cessation for reducing wound complications is unclear.

Methods

One hundred eighty-eight consecutive patients who underwent reconstructive head and neck surgery at the authors' institution were included in this retrospective study. Information on preoperative smoking habits was obtained from the patients' medical records. Smokers were defined as having smoked within 7 days before surgery. Late, intermediate, and early quitters were defined as patients whose duration of abstinence from smoking was 8-21, 22-42, and 43 days or longer before the operation, respectively. Patients who required postoperative debridement, resuture, or reconstruction of their flap before hospital discharge were defined as having had impaired wound healing.

Results

The incidences (95% confidence intervals) of impaired wound healing among the late, intermediate, and early quitters and nonsmokers were 67.6% (52-83%), 55.0% (33-77%), 59.1% (47-71%), and 47.5% (32-63%), respectively, and the incidence of impaired wound healing was significantly lower among the intermediate quitters, early quitters, and nonsmokers than among the smokers (85.7% [73-97%]). After controlling for sex, age, American Society of Anesthesiologists physical status, operation time, history of diabetes mellitus, chemotherapy, radiation therapy, and the type of flap, the odds ratios (95% confidence intervals) for development of impaired wound healing in the late, intermediate, early quitters, and nonsmokers were 0.31 (0.08-1.24), 0.17 (0.04-0.75), 0.17 (0.05-0.60), and 0.11 (0.03-0.51), respectively, compared with the smokers.

Conclusions

Preoperative smoking abstinence of longer than 3 weeks reduces the incidence of impaired wound healing among patients who have undergone reconstructive head and neck surgery.
Sevoflurane Blocks Cholinergic Synaptic Transmission Postsynaptically but Does Not Affect Short-term Potentiation
Authors: Naruo Hiroaki , Onizuka Shin , Prince David , Takasaki Mayumi , Syed Naweed I.
Published: April 2005

Background

As compared with their effects on both inhibitory and excitatory synapses, little is known about the mechanisms by which general anesthetics affect synaptic plasticity that forms the basis for learning and memory at the cellular level. To test whether clinically relevant concentrations of sevoflurane affect short-term potentiation involving cholinergic synaptic transmission, the soma-soma synapses between identified, postsynaptic neurons were used.

Methods

Uniquely identifiable neurons visceral dorsal 4 (presynaptic) and left pedal dorsal 1 (postsynaptic) of the mollusk Lymnaea stagnalis were isolated from the intact ganglion and paired overnight in a soma-soma configuration. Simultaneous intracellular recordings coupled with fluorescent imaging of the FM1-43 dye were made in either the absence or the presence of sevoflurane.

Results

Cholinergic synapses, similar to those observed in vivo, developed between the neurons, and the synaptic transmission exhibited classic short-term, posttetanic potentiation. Action potential-induced (visceral dorsal 4), 1:1 excitatory postsynaptic potentials were reversibly and significantly suppressed by sevoflurane in a concentration-dependent manner. Fluorescent imaging with the dye FM1-43 revealed that sevoflurane did not affect presynaptic exocytosis or endocytosis; instead, postsynaptic nicotinic acetylcholine receptors were blocked in a concentration-dependent manner. To test the hypothesis that sevoflurane affects short-term potentiation, a posttetanic potentiation paradigm was used, and synaptic transmission was examined in either the presence or the absence of sevoflurane. Although 1.5% sevoflurane significantly reduced synaptic transmission between the paired cells, it did not affect the formation or retention of posttetanic potentiation at this synapse.

Conclusions

This study demonstrates that sevoflurane blocks cholinergic synaptic transmission postsynaptically but does not affect short-term synaptic plasticity at the visceral dorsal 4-left pedal dorsal 1 synapse.
Xenon Attenuates Cerebral Damage after Ischemia in Pigs
Authors: Schmidt Michael , Marx Thomas , Glöggl Egon , Reinelt Helmut , Schirmer Uwe
Published: April 2005

Background

Cerebral blood flow may be compromised in a variety of anesthetic procedures, and ischemic cerebral complications represent the leading cause of morbidity after cardiac operations. With the growing importance of neuroprotective strategies, the current study was designed to determine whether xenon would attenuate cardiac arrest-induced brain injury in pigs.

Methods

Twenty-four pigs (aged 12-16 weeks) were investigated in a randomized design. General hemodynamics, intracranial pressure, brain tissue oxygenation, and cerebral microdialysis parameters were investigated. The animals were assigned to two groups to receive anesthesia with either xenon (75%) in oxygen (25%) or total intravenous anesthesia combined with air in oxygen (25%) ventilation 15 min before cardiac arrest. After induction (t0) of cardiac arrest of 4 min, cardiopulmonary resuscitation was performed for 1 min, and the induced ventricular fibrillation was terminated by electrical defibrillation. The investigation time was 240 min.

Results

Approximately 60 s after cardiac arrest, brain tissue oxygenation decreased to a critical level of less than 5 mmHg, paralleled by a decrease in electroencephalographic activity. Glycerol as a damage marker increased significantly (> 200 m; P < 0.05), with a peak 90 min after cardiac arrest in both groups. Glycerol concentrations during reperfusion were significantly lower and normalized faster in the xenon group as compared with the total intravenous anesthesia group.

Conclusion

Although the primary ischemic lesion in this model was similar in both groups, the cerebral microdialysis data show that xenon induces a differential neurochemical benefit in cerebral cell damage and metabolism as compared with total intravenous anesthesia in vivo during cerebral reperfusion after cardiac arrest in a pig model.