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Kinds of Data. Selected AbstractsEvaluation of Three Algorithms to Identify Incident Breast Cancer in Medicare Claims DataHEALTH SERVICES RESEARCH, Issue 5 2007Heather T. Gold Objective. To test the validity of three published algorithms designed to identify incident breast cancer cases using recent inpatient, outpatient, and physician insurance claims data. Data. The Surveillance, Epidemiology, and End Results (SEER) registry data linked with Medicare physician, hospital, and outpatient claims data for breast cancer cases diagnosed from 1995 to 1998 and a 5 percent control sample of Medicare beneficiaries in SEER areas. Study Design. We evaluate the sensitivity and specificity of three algorithms applied to new data compared with original reported results. Algorithms use health insurance diagnosis and procedure claims codes to classify breast cancer cases, with SEER as the reference standard. We compare algorithms by age, stage, race, and SEER region, and explore via logistic regression whether adding demographic variables improves algorithm performance. Principal Findings. The sensitivity of two of three algorithms is significantly lower when applied to newer data, compared with sensitivity calculated during algorithm development (59 and 77.4 percent versus 90 and 80.2 percent, p<.00001). Sensitivity decreases as age increases, and false negative rates are higher for cases with in situ, metastatic, and unknown stage disease compared with localized or regional breast cancer. Substantial variation also exists by SEER registry. There was potential for improvement in algorithm performance when adding age, region, and race to an indicator variable for whether the algorithm determined a subject to be a breast cancer case (p<.00001). Conclusions. Differential sensitivity of the algorithms by SEER region and age likely reflects variation in practice patterns, because the algorithms rely on administrative procedure codes. Depending on the algorithm, 3,5 percent of subjects overall are misclassified in 1998. Misclassification disproportionately affects older women and those diagnosed with in situ, metastatic, or unknown-stage disease. Algorithms should be applied cautiously to insurance claims databases to assess health care utilization outside SEER-Medicare populations because of uneven misclassification of subgroups that may be understudied already. [source] Correlation of Density Pedestal Width and Neutral Penetration LengthCONTRIBUTIONS TO PLASMA PHYSICS, Issue 1-3 2004X. Q. Xu Abstract Pedestal studies in DIII-D and MAST find good correlation between the width of the H-mode density barrier and the neutral penetration length [1, 2]. These results suggest that the width may be set by the combined effects of neutrals and plasma transport. This paper is a report on fluid simulations of boundary plasma using the BOUT code[3] with a neutral source added. Thus both neutral and plasma physics are treated. The plasma transport is self-consistently driven by boundary turbulence due to the resistive X-point mode, while neutrals are described by a simple analytic model. The plasma profiles are evolved on the same time scale as the turbulence for the given heat source from the core plasma and particle source from the neutrals. For prescribed neutral profiles, we find the formation of a density pedestal inside the separatrix in the L-mode even though the calculated plasma diffusion coefficients are almost radially constant and without the formation of a temperature pedestal. These results support the hypothesis that particle fueling can provide the dominant control for the size of the H-mode density barrier. The width of the density barrier decreases as the pedestal density increases which is also consistent with experimental data. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Blob Transport in the Tokamak Scrape-off-LayerCONTRIBUTIONS TO PLASMA PHYSICS, Issue 1-3 2004D. A. D'Ippolito Abstract Recent experimental evidence suggests the importance of fast radial plasma transport in the scrape-off-layer (SOL) of tokamaks. The outward transport appears to be convective rather than diffusive, extends into the far SOL, and can produce significant recycling from the main-chamber walls, partially bypassing the divertor. A plausible theoretical mechanism to explain this phenomenon is the radial transport of "blobs" of locally dense plasma created by turbulent processes. A related process is the inward transport of "holes" of reduced density plasma, which provides a mechanism for rapid inward transport of impurities. The blob model is also consistent with the spatial and temporal intermittency and the non-Gaussian statistics observed in the SOL plasma. This paper reviews the present status of blob theory, including analytic models and simulations, and discusses the preliminary comparisons of the blob model with experimental data. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Application of mean-separation-works method to protein crystal nucleationCRYSTAL RESEARCH AND TECHNOLOGY, Issue 3 2008Christo N. Nanev Abstract Using mean-separation-works method of Stranski and Kaischew calculations of nucleus form and energy barrier for its formation are performed for globular protein crystals. This is done on the basis of a simple model suggested for crystal nucleation of such proteins. The prerequisite for the model is the fact that strict selection of definite sticky patches on protein molecule surface is obligatory for forming crystal lattices. The calculation results are in agreement with experimental data. (© 2008 WILEY -VCH Verlag GmbH & Co. KGaA, Weinheim) [source] The impact of SiC substrate treatment on the heteroepitaxial growth of GaN by plasma assisted MBECRYSTAL RESEARCH AND TECHNOLOGY, Issue 10-11 2005A. S. Brown Abstract We report on the impact of the preparation of the Si-face 4H-SiC(0001)Si substrate using a Ga flash-off process on the epitaxial growth of GaN by plasma-assisted molecular beam epitaxy. The nucleation, as well as the resultant structural and morphological properties of GaN grown directly on 4H-SiC(0001)Si are strongly influenced by the chemical and morphological modifications of the SiC surface induced by the Ga flash-off process. Herein we describe the impact of the specific concentration of Ga incident on the surface (quantified in terms of monolayer (ML) coverage): of 0.5 ML, 1ML and 2ML. The residual oxygen at the SiC surface, unintentional SiC nitridation and the formation of cubic GaN grains during the initial nucleation stage, are all reduced when a 2 ML Ga flash is used. All of the above factors result in structural improvement of the GaN epitaxial layers. The correlation between the SiC surface modification, the initial nucleation stage, and the GaN epitaxial layer structural quality has been articulated using x-ray photoelectron spectroscopy, x-ray diffraction, atomic force microscopy and spectroscopic ellipsometry data. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Pilot-scale combustion of fast-pyrolysis bio-oil: Ash deposition and gaseous emissionsENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 3 2009Ala Khodier Abstract Fast pyrolysis is a promising method to transform solid biomass into a liquid product called "bio-oil" with an energy density of four to five times greater than the feedstock. The process involves rapidly heating biomass to 450,600°C in the absence of air and condensing the vapor produced to give bio-oil. Typically, 50,75% (weight) of the feedstock is converted into bio-oil that has a number of uses, for example energy production or bio-refinery feedstock. This study investigated the gaseous emissions and ash deposition characteristics resulting from bio-oil combustion in a pilot scale combustion test rig at Cranfield University. A feeding system with heated lines and heated/stirred reservoir was used to feed a spray nozzle in the combustion chamber. Ash deposit samples were collected from the resulting flue gas using three air-cooled probes that simulate heat exchanger tubes with surface temperatures of 500, 600, and 700°C. The deposits formed were analyzed using SEM/EDX and XRD techniques to assess the corrosion potential of the deposits. The results are compared to measured ash deposit compositions formed from biomass combustion. Thermodynamic modeling software was used to make predictions for the partitioning of a range of elements for bio-oil combustion and the results compared to the measured data. © 2009 American Institute of Chemical Engineers Environ Prog, 2009 [source] Solid-State and Solution Structure of Lanthanide(III) Complexes with a Flexible Py-N6 Macrocyclic LigandEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 8 2009Cristina Núñez Abstract Lanthanide complexes of a hexaaza macrocyclic ligand containing a pyridine head unit (L) were synthesized (Ln = La,Lu, except Pm). The solid-state structures of the corresponding La, Ce, Pr, Nd, and Lu complexes were determined by single-crystal X-ray crystallography, and they reveal the presence of three different mononuclear complexes with three different conformations of the macrocycle and coordination environments around the metal ions. In all complexes the lanthanide ion is coordinated in an endomacrocyclic manner to the six nitrogen donor atoms of the ligand. In the La, Ce, and Pr complexes the metal ions show a 12-coordinate mononuclear environment in which 3 nitrate anions coordinate in a bidentate fashion. However, in the Nd analogue the metal ion displays a 10-coordinated environment with the coordination of 2 bidentate nitrate groups, whereas Lu shows a 9-coordinate environment interacting with 2 nitrate ligands, one of them acting as bidentate and the second one coordinating in a monodentate fashion. The 1H and 13C NMR spectra of the complexes recorded in CD3CN suggest that the complexes adopt in solution a similar structure to that observed for the Nd complex in the solid state. The [Ln(L)(NO3)3] and [Ln(L)(NO3)2]+ complexes were characterized by density functional theory (DFT) calculations (B3LYP model). The structures obtained from these calculations for La, Ce, Pr, and Nd are in good agreement with the experimental solid-state structures. The relative stabilities of the [Ln(L)(NO3)2]+ complexes with respect to the [Ln(L)(NO3)3] ones (Ln = La, Nd, Gd, Ho, or Lu) were studied both in vacuo and in acetonitrile solution (PCM model) at the same computational level. Our calculations indicate that in solution the [Ln(L)(NO3)2]+ species is the most stable one along the whole lanthanide series, in agreement with the NMR spectroscopic data.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Synthesis, Characterisation and Optical Properties of Silica Nanoparticles Coated with Anthracene Fluorophore and Thiourea Hydrogen-Bonding SubunitsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 36 2008Pilar Calero Abstract Bifunctionalised hybrid silica nanoparticles have been synthesised and characterised, and their optical emission properties in the presence of certain anions in acetonitrile solutions have been studied. The alkoxysilane derivatives N -butyl- N, -[3-(trimethoxysilyl)propyl]thiourea (1), N -phenyl- N, -[3-(trimethoxysilyl)propyl]thiourea (2) and 3-[(anthracen-10-yl)methylthio]propyltriethoxysilane (3) were prepared and used to functionalise uncoated LUDOX silica nanoparticles with a mean diameter of 18,±,2 nm. The functionalisation of the nanoparticle surfaces was carried out by two different approaches. The first approach relies on the consecutive grafting of the two subunits. In this protocol, the nanoparticles were first functionalised with anthracene derivative 3 (solid NA), and then treated with the corresponding binding sites 1 or 2 to result in the NA-Pt3 and NA-Bt3 solids. The second approach deals with the simultaneous grafting of 1 or 2 and the signalling subunit 3 in different ratios. This method was used for the preparation of the NA1Pt1, NA1Bt1, NA1Pt3 and NA1Bt3 nanoparticles. The bifunctionalised silica nanoparticles were characterised by using standard techniques. Acetonitrile suspensions of NA nanoparticles (5 mg in 20 mL) showed anthracene bands centred at ca. 350, 370 and 390 nm. Upon excitation at 365 nm, a typical emission band with fine structure in the 390,450 nm range was observed. Similar absorption and emission spectra were found for the bifunctionalised nanoparticles. The work is completed with a prospective study of the fluorescence of the prepared nanoparticles in the presence of organic (acetate, benzoate) and inorganic (F,, Cl,, Br,, CN,, HSO4, and H2PO4,) anions. The apparent binding constants (adsorption constants) for the interaction of NA-Pt3 with anions in acetonitrile were determined by performing a Langmuir-type analysis of fluorescence titration data.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Ligand-Exchange Processes on Solvated Lithium Cations: Acetonitrile and Hydrogen Cyanide,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2007Ewa Pasgreta Abstract Solutions of LiClO4 in solvent mixtures of acetonitrile and water, or acetonitrile and nitromethane, were studied by 7Li NMR spectroscopy. Measured chemical shifts indicate that the Li+ cation is coordinated by four acetonitrile molecules. In the binary water/acetonitrile mixture, water coordinates more strongly to Li+ than acetonitrile such that addition of water immediately leads to the formation of [Li(H2O)4]+. The solvent-exchange mechanism for [Li(L)4]+ (L = CH3CN and HCN) was studied by using DFT calculations (RB3LYP/6-311+G**). This process was found to follow a limiting associative mechanism involving the formation of relatively stable five-coordinate intermediates. The suggested mechanisms are discussed with reference to available experimental and theoretical data. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Receptor versus Counterion: Capability of N,N, -Bis(2-aminobenzyl)-diazacrowns for Giving Endo- and/or Exocyclic Coordination of ZnIIEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2007Lea Vaiana Abstract The structure of ZnII complexes with receptors L1 and L2[L1 = N,N, -bis(2-aminobenzyl)-1,10-diaza-15-crown-5 and L2 = N,N, -bis(2-aminobenzyl)-4,13-diaza-18-crown-6] was studied both in the solid state and in acetonitrile solution. Both receptors form mononuclear ZnII complexes in this solvent, while no evidence for the formation of dinuclear complexes was obtained. This is in contrast with previous investigations that demonstrated the formation of dinuclear complexes of L2 with first-row transition metals such as NiII, CoII and CuII. Compounds of formula [Zn(L1)](ClO4)2 (1), [Zn(L1)](NO3)2·2CH3CN (2), [Zn(L2)](ClO4)2 (3) and [Zn(L2)(NO3)2] (4) were isolated and structurally characterised by X-ray diffraction analyses. L1 forms seven-coordinate ZnII complexes in the presence of both nitrate and perchlorate anions, as a consequence of the good fit between the macrocyclic cavity and the ionic radius of the metal ion. The ZnII ion is deeply buried into the receptor cavity and the anions are forced to remain out of the metal coordination sphere. The cation [Zn(L1)]2+ present in 1 and 2 is one of the very few examples of seven-coordinate Zn complexes. Receptor L2 provides a very rare example of a macrocyclic receptor allowing endocyclic and exocyclic coordination on the same guest cation, depending on the nature of the anion present. Thus, in 3 the ZnII ion is endocyclically coordinated, placed inside the crown hole coordinated to four donor atoms of the ligand in a distorted tetrahedral environment, whereas in 4, the presence of a strongly coordinating anion such as nitrate results in an exocyclic coordination of ZnII, which is directly bound only to the two primarily amine groups of L2 and two nitrate ligands. Spectrophotometric titrations of [Zn(L2)]2+ with tetrabutylammonium nitrate in acetonitrile solution demonstrate the stepwise formation of 1:1 and 1:2 adducts with this anion in acetonitrile solution. The [Zn(L1)]2+, [Zn(L2)]2+ and [Zn(L2)(NO3)2] systems were characterised by means of DFT calculations (B3LYP model). The calculated geometries show an excellent agreement with the experimental structures obtained from X-ray diffraction analyses. Calculated binding energies of the macrocyclic ligands to ZnII are also consistent with the experimental data.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Hydrogen Evolution from Peroxides , a Concerted ReactionEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 14 2004Werner R. Thiel Abstract DFT calculations provide strong evidence that the evolution of hydrogen from mixtures of aldehydes and hydrogen peroxide proceeds by a concerted mechanism. The electronic influence of a series of substituents is correlated with the enthalpies of activation and reaction, and the calculated isotope effect of the reaction is compared with experimentally obtained data. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Stereoselective Hydrolysis of Quaternary Quinuclidinium Benzoates Catalyzed by ButyrylcholinesteraseEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 2 2003Ines Primoz Abstract Four chiral, quaternary, N -methyl and N -benzyl derivatives of (R)- and (S)-quinuclidin-3-yl benzoates were synthesized and studied as substrates of horse serum butyrylcholinesterase (BChE). The kcat for the substrates decreased in the order (R)- N -methyl > (R)- N -benzyl (2.3-fold slower) >> (S)- N -methyl (70.5-fold slower reaction), while for the (S)- N -benzyl ester inhibition of the enzyme was observed. The kinetics of inhibition (Ka = 3.3 ,M) indicated that binding to the catalytic site of BChE occurred. From the ratio of the kcat/KM values of both enantiomers an enantiomeric excess of 95% was calculated for N -methyl derivatives. Thus, BChE is suitable as a biocatalyst for the resolution of racemic quaternary quinuclidinium esters. In order to explain the experimental data, combined quantum chemical (HF/3,21G*) and semiempirical (PM3) calculations within the ONIOM scheme of the stable species in the acylation step were performed. Geometry optimizations were carried out for all benzoate esters for an assumed active site model of BChE. It was confirmed that hydrolysis is affected to an appreciable extent by a proper geometrical orientation of substrates at the choline subsite. The energies of the optimized systems were in good agreement with the experimental data. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] A contribution to the phylogeny of annual species of Astragalus (Fabaceae) in the Old World using hair micromorphology and other morphological charactersFEDDES REPERTORIUM, Issue 5-6 2007F. Taeb A cladistic analysis including 32 annual and nine perennial species of Astragalus along with four outgroups from related genera is performed using characters from hair micromorphology, floral morphology and some other morphological sources. The hair characters show the similar evolutionary trends as known earlier for the genus Astragalus, but they exhibit lower variability in comparison with other major subgroups of Astragalus. The obtained data was compared with the data from molecular systematics. The most important results of this study are: 1) medifixed hairs are developed at least two times among annual Astragalus, 2) fruit morphology, does not provide strong evidence in delimitation of the sections within annual Astragalus, 3) presence of long and thick hairs with largely tuberculate base should be considered as an advanced character, and can be regarded as an important synapomorphy among annual Astragalus, 4) the position of some species of the large and heterogeneous sect. Sesamei, e.g. A. persepolitanus and A. coronilla, and their possible close relationship with the species of the sect. Oxyglottis should be re-assessed, 5) the species of the sect. Ankylotus show close relationship to sect. Platyglottis, based on floral morphology and hair characters, 6) there are not enough supports from hair, floral morphology and biogeography for considering A. annularis, A. epiglottis (as Glottis epiglottis), A. pelecinus (as Biserrula pelecinus) and A. vogelii (as Podlechiella vogelii) as separated from Astragalus (as suggested by molecular data). Moreover, the inclusion of Barnebyella calycina again in Astragalus is well supported by morphological data. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Zur Phylogenie annueller Arten von Astragalus (Fabaceae) in der Alten Welt auf der Basis der Haar-Mikromorphologie und anderer morphologischer Merkmale Eine kladistische Analyse, umfassend 32 annuelle und neun perennierende Arten von Astragalus mit vier Nebengruppen verwandter Gattungen, wurde auf der Basis von Mikromorphologie, Blütenmorphologie und einiger anderer morphologischer Quellen vorgenommen. Die Merkmale der Haare zeigen ähnliche evolutionäre Tendenzen wie sie bereits früher von der Gattung Astragalus bekannt waren, doch zeigen sie im Vergleich zu anderen, umfassenderen Untergruppen von Astragalus, eine geringere Variabilität. Die so gewonnenen Daten werden mit Daten der molekularen Systematik verglichen. Die wichtigsten Ergebnisse dieser Studie sind: 1. Die im mittleren Bereich fixierten Haare entwickelten sich innerhalb der annuellen Astragalus zweimal; 2. Die Morphologie der Früchte liefert keinen eindeutigen Beweis zur Abgrenzung der Sektionen innerhalb der annuellen Astragalus -Arten; 3. Die Anwesenheit langer, dicker Haare mit einer großen tuberkularen Basis ist als abgeleitetes Merkmal zu betrachten und kann als wichtige Synapomorphie innerhalb annueller Astragalus -Arten betrachtet werden; 4. Die Stellung einiger Arten der großen, heterogenen Sekt. Sesamei, z. B. A. persepolitanus und A. coronilla und ihre möglicherweise enge Verwandtschaft mit den Arten der Sekt. Oxyglottis sollte neu beurteilt werden. 5. Die Arten der Sekt. Ankylotus zeigen aufgrund ihrer Blütenmorphologie und der Merk- male ihrer Haare enge Verwandtschaft zur Sekt. Platyglottis; 6. Es gibt nicht genügend Hinweise bezüglich Haare, Blütenmorphologie und Biogeographie um A. annularis, A. epiglottis (als Glottis epiglottis), A. pelecinus (als Biserrula pelecinus) und A. vogelii (als Podlechiella vogelii) von Astragalus abzutrennen (wie es die molekularen Daten aussagen). Dagegen ist die Wiedereingliederung von Barnebyella calycina in die Gattung Astragalus gut durch die morphologischen Daten gestützt. [source] Numeracy and the shortcomings of utility assessment in head and neck cancer patients,,HEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 5 2004Seth R. Schwartz MD Abstract Background. Because survival differences between surgical and nonsurgical treatment for head and neck cancer (HNC) are hard to detect, increasing focus has been placed on quality of life (QOL) differences after treatment. Utility assessment provides insight into QOL. Evidence suggests that a patient's comfort with numerical concepts ("numeracy") may influence utility measures. We hypothesize that patients who are nonnumerate provide inconsistent utility data in QOL studies. Methods. New HNC (n = 18) patients were recruited to participate. Patients completed a numeracy questionnaire, a utility assessment, and a global QOL questionnaire. Higher scores reflect better function. Interviewers rated the functional level of each patient. For both numerate and nonnumerate patients, utility scores were compared with global QOL (good vs poor) and observer-rated function. Results. Half of the patients were numerate. Numerate patients who rated their QOL as good had significantly higher utility scores than did patients with poor global QOL (0.95 vs 0.43, p = .03). In contrast, nonnumerate patients with good QOL had lower utility scores than did patients with poor QOL (0.45 vs 0.77, NS). Utility scores for numerate patients correlated well with observer-rated function (r = 0.41 to r = 0.57), whereas those of nonnumerate patients did not (r = ,0.16 to r = 0.06). Conclusions. QOL evaluation through utility assessment may provide inaccurate and contradictory data about patient functioning for nonnumerate patients. This may confound QOL assessment when interpreting utility data. © 2004 Wiley Periodicals, Inc. Head Neck26: 401,407, 2004 [source] Synthesis, characterization, and solution properties of some new organotellurium compounds based on di(cyclohexylmethyl)tellurideHETEROATOM CHEMISTRY, Issue 1 2007Ali Z. Al-Rubaie A new series of organotellurium(IV) compounds based on di(cyclohexylmethyl)telluride (1) (i.e., (C6H11CH2)2TeX2 and (C6H11CH2)2Te(R)X) was prepared by the reaction of compound 1 with halogens, N-bromosuccinimide, and alkyl halides. Phenylation of (C6H11CH2)2TeX2 with sodium tetraphenylborate gave di(cyclohexylmethyl)phenyltelluronium tetraphenylborate in good yield. Conductivity measurements in dimethylsulfoxide (DMSO) showed a considerable ionic character of these compounds and they behave as 1:1 electrolytes. 1H NMR studies in CDCl3 solution indicated that telluronium salts employed in this study are unstable toward reductive elimination. Reaction of di(cyclohexylmethyl)telluride, (C6H11CH2)2Te(CH3)I, and (C6H11CH2)2Te(PhCH2)Br with HgX2 (X = Cl or Br) afforded 1:1 complexes. All compounds were characterized by elemental analyses and spectroscopic data. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:93,99, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20240 [source] Regioselective formation of a 2,3-oxaphosphabicyclo[2.2.2]octene 3-oxide in Baeyer,Villiger type oxidation; a dual pathway for its fragmentationHETEROATOM CHEMISTRY, Issue 5 2006Stefan Jankowski The O-insertion reaction of a 7-phos- phanorbornene (3) unsubstituted on the double- bond gave the corresponding 2,3-oxaphosphabicyclo- [2.2.2]octene oxide (4a) in a regioselective manner that was useful in the fragmentation-related phosphonylation of alcohols. Both the UV-light mediated and the thermoinduced phosponylation accomplished on the bridged P-heterocycle (4a) were found to be sensitive toward steric factors, suggesting that beside the well-known elimination,addition reaction path taking place via metaphosphonate (11), a competitive novel addition--elimination route involving an intermediate with a pentacoordinated P-atom (12) is also present. This was confirmed by the kinetic consideration of our experimental data. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:369,375, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20213 [source] An expedient synthesis of novel, fused pyrimido[4,5- d]pyrimidine and pyrimido [5,4- e] [1,2,4]triazolo[4,3- c]pyrimidine analogues from 4-amino-2,6-dichloro-pyrimidineHETEROATOM CHEMISTRY, Issue 4 2006Pratibha Sharma A number of potent pyrimido[4,5-d]pyrimidine have efficiently been synthesized by the condensation of 4-amino-2,6-dichloropyrimidine with various substituted benzaldehyde followed by cyclization with ammonium thiocyanate. Also, these newly synthesized derivatives were utilized for the construction of novel pyrimido[5,4-e][1,2,4]triazolo[4,3-c]pyrimidine analogues via oxidative cyclization involving 1,5-hydrogen abstraction. Structure of all the newly constructed derivatives was corroborated by the elemental and spectral data. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:245,253, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20177 [source] Syntheses and spectroscopic investigation of some cyclophosphazanes: Analysis of pseudo-triplet splittingHETEROATOM CHEMISTRY, Issue 4 2006Khodayar Gholivand Some new phosphoramidates, 1,3, and the corresponding cyclophosphazanes, 4,6, with formula Cl2P(p -NHC6H4CH3) 1, Cl2P(O)(p -NHC6H4NO2) 2, (CH3)2NP(O)Cl(p -NHC6H4CH3)3, [ClP(p -NC6H4CH3)]24, [ClP(O)(p -NC6H4NO2)]25, and [(CH3)2NP(O)(p -NC6H4CH3)]26 were synthesized and characterized by 1H, 13C, 31P NMR, IR, mass spectroscopy, and elemental analysis. A pseudo-triplet signal was observed in the 1H NMR spectrum of molecule 6 for the N(CH3)2 protons. The A6A, 6X2 spin system was suggested for the pseudo-triplet pattern of 3JPNCH coupling in this molecule. Ab initio calculations were performed at the HF and B3LYP levels of theory with 6-311G** standard basis set on the geometry of compound 6. Also, the NMR chemical shift calculations were done to compare the computed results with the experimental ones. The calculated results are in good agreement with experimental data. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:337,343, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20229 [source] Chemistry of phosphorus ylides 21 new route for the synthesis of azetidinones.HETEROATOM CHEMISTRY, Issue 6 2005Reaction of phosphonium ylides with benzil-, o -naphthoquinone-, triketonemonoanils Active vinylidenetriphenylphosphoranes are nucleophilic reagents which can be con- sidered as versatile synthons for the synthesis of new heterocycles. The active phosphacumulene ylides, namely N -phenylimino- 2a, 2-oxo- 2b or 2-thioxo-vinylidenetriphenylphosphoranes (2c), react with benzil- (1a,b), o -naphthoquinone- (8), or triketone-monoanils (11), to give the corresponding phenylimino- (3a, d, 9a, 12a), oxo- (3b, e, 9b, 12b), or thioxoazetidinones (3c, f, 9c, 12c), respectively, which constitute an important class of organic compounds with medicinal and biological importance. On the other hand, quinone monoanils 1a, 8, 11 can be converted by reaction with the stabilized alkylidenephosphoranes (5a,d), namely acetylmethylene- 5a, methoxycarbonylmethylene- 5b, ethoxycarbonylmethylene- 5c, and benzoylmethylene-triphenylphosphorane 5d, into the phosphoranylidenes (7a,d, 10a,d, 13a,d). No reaction was observed between iminophosphorane (14) and the monoanil (11). The structures of the new products were assigned according to consistent analytical and spectroscopic data. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:476,483, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20144 [source] Reactions of 2-amino-3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophene and 2-amino-3-cyano-4,7-diphenyl-5-methyl-4H -pyrano[2,3- c] pyrazole with phenylisocyanate, carbon disulfide, and thioureaHETEROATOM CHEMISTRY, Issue 1 2005Ahmed S. A. Youssef 2-Amino-3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophene 1a or 2-amino-3-cyano-4,7-di- phenyl-5-methyl-4H -pyrano[2,3- c]pyrazole 2a reacted with phenylisocyanate in dry pyridine to give 2-(3-phenylureido)-3-cyanobenzo[b]thiophene 1b or 2-disubstituted amino-3-cyanopyranopyrazole 2b derivative. However, when 1a and 2a were refluxed with carbon disulfide in 10% ethanolic sodium hydroxide solution, they afforded the thieno[2,3- d]pyrimidin-2,4-dithione derivative 5 in the former case, 2,4-dicyano-1,3-bis(dithio carboxamino)cyclobuta-1,3- diene 6 and pyrazolopyranopyrido[2,3- d]pyrimidin- 2,4-dithione derivative 7 in the latter one. Treatment of 2a with thiourea in refluxing ethanol in the presence of potassium carbonate gave 2,2,-dithiobispyrimidine derivative 9 (major) in addition to pyranopyrazole derivative 10 and 2,2,-dithiobis ethoxypyrimidine derivative 11 in minor amounts. The structures of all products were evidenced by microanalytical and spectral data. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:6,11, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20070 [source] Synthesis of sulfur-containing heterocycles: spiropyrimidinetriones, thioxopyrimidinediones, pyrazolidinediones, and isoxazolidinediones,part iiHETEROATOM CHEMISTRY, Issue 3 2001D. Bhaskar Reddy 1-Aroyl-2-styrylsulfonylethene is the precursor for 4,4-dimethoxycarbonyl-2,,5-diaryl-3-(1,,3,-dioxolano)-1-thia-1,1-dioxide (4), which is the key intermediate for the synthesis of 7-aroyl-11-aryl-2,4-diazaspiro[5,5]undecane-1,3,5-trione-9-thia-9,9-dioxide(10)/3-thioxo-1,5-dione-9-thia-9,9-dioxide (11), 6-aroyl-10-aryl-2,3-diazaspiro[4,5]decane-1,4-dione-8-thia-8,8-dioxide (12)/2-oxo-3-azaspiro [4,5]decane-1,4-dione-8-thia-8,8-dioxide (13). The new compounds were characterized by IR and 1H NMR spectral data. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:131,135, 2001 [source] Neuropsychological correlates of hippocampal and rhinal cortex volumes in patients with mesial temporal sclerosisHIPPOCAMPUS, Issue 8 2003Catherine E. O'Brien Abstract Considerable progress has been made toward understanding the function of the primate rhinal cortex, comprising the entorhinal (ErC) and perirhinal (PrC) cortices. However, translating animal models to human memory has been limited by the technological problems associated with characterizing neural structures in vivo. Functional correlates of hippocampal and rhinal cortex volume changes were examined in a sample of 61 temporal lobe epilepsy patients with mesial temporal sclerosis (MTS; 33 left, 28 right). Patients were administered the Wechsler Adult Intelligence Scale (revised or third edition), the Wechsler Memory Scale (revised or third edition), and a spatial maze task. Neuropsychological data, together with rhinal cortex and hippocampal volumes, collected in our earlier study (O'Brien CE, Bowden SC, Whelan G, Cook MJ, unpublished observations), were analyzed using multiple regression. The only significant predictor of verbal memory function was the difference score between the volume of left hippocampus and the left PrC. Spatial maze scores were predicted by the bilateral sum of ErC volume. The difference score between the left hippocampus and left PrC volumes was the most powerful predictor of verbal episodic memory. Right hippocampal volume was not a significant predictor of nonverbal episodic memory. Verbal and nonverbal semantic memory were not significantly predicted by any combination of rhinal cortex structures. This quantitative study suggests a lateralized or material-specific memory function for the left hippocampus and left PrC, in contrast to the bilateral role of the ErC. The left hippocampus and left PrC appear to act on verbal memory function through an opposing relationship. Finally, differentiation between hippocampal and subhippocampal components in terms of episodic and semantic memory, respectively, could not be supported by the current data. © 2003 Wiley-Liss, Inc. [source] Using feedforward neural networks and forward selection of input variables for an ergonomics data classification problemHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 1 2004Chuen-Lung Chen A method was developed to accurately predict the risk of injuries in industrial jobs based on datasets not meeting the assumptions of parametric statistical tools, or being incomplete. Previous research used a backward-elimination process for feedforward neural network (FNN) input variable selection. Simulated annealing (SA) was used as a local search method in conjunction with a conjugate-gradient algorithm to develop an FNN. This article presents an incremental step in the use of FNNs for ergonomics analyses, specifically the use of forward selection of input variables. Advantages to this approach include enhancing the effectiveness of the use of neural networks when observations are missing from ergonomics datasets, and preventing overspecification or overfitting of an FNN to training data. Classification performance across two methods involving the use of SA combined with either forward selection or backward elimination of input variables was comparable for complete datasets, and the forward-selection approach produced results superior to previously used methods of FNN development, including the error back-propagation algorithm, when dealing with incomplete data. © 2004 Wiley Periodicals, Inc. Hum Factors Man 14: 31,49, 2004. [source] Study of four genes belonging to the folate pathway: transcobalamin 2 is involved in the onset of non-syndromic cleft lip with or without cleft palate,,HUMAN MUTATION, Issue 3 2006Marcella Martinelli Abstract Cleft lip with or without cleft palate (CL/P) is the most common inborn craniofacial anomaly. Affected individuals require extensive medical and psychosocial support. Although CL/P has a complex and poorly understood etiology, increasing evidence of folate pathway involvement has been collected. So far, only the MTHFR gene has been extensively investigated as a risk factor for CL/P, while little has been done to test genetic variations in the folate biosynthetic pathways that may influence the infant's susceptibility to these birth defects. To date, this paper presents the first attempt to verify the involvement of four genes belonging to the folate pathway in nonsyndromic cleft onset. We used a case-parent triad design to test for linkage disequilibrium in the case of seven SNPs mapping on four different genes: transcobalamin 1 and 2 (TCN1 and TCN2), methionine synthase (MTR), and MTR reductase (MTRR). Our finding suggests that TCN2 is involved in causing CL/P. Indeed, significant overtransmission of the C allele was observed at the polymorphism c.776C>G (p.Pro259Arg) to the affected offspring (P=0.01). Results obtained with additional TCN2 polymorphisms suggest that c.776C>G may be functionally related to CL/P. However, because conflicting data exist with regard to the effect of the polymorphism in transcobalamin 2 function or in perturbing plasma levels of key molecules in the folate pathway, further investigation is warranted to confirm our data. © 2006 Wiley-Liss, Inc. [source] RETIREMENT WEALTH AND LIFETIME EARNINGS,INTERNATIONAL ECONOMIC REVIEW, Issue 2 2007Lutz Hendricks This article argues that a satisfactory theory of wealth inequality should account not only for the marginal distribution of wealth, but also for the joint distribution of wealth and earnings. The article describes the joint distribution of retirement wealth and lifetime earnings in the Panel Study of Income Dynamics. It then evaluates the ability of a stochastic life-cycle model to account for key features of this distribution. The life-cycle model fails to account for three key features of the data. (1) The correlation between lifetime earnings and retirement wealth is too high. (2) The wealth gaps between earnings rich and earnings poor households are too large. (3) Wealth inequality among households with similar lifetime earnings is too small. Models in which households differ in rates of return or time preferences account much better for the joint distribution of retirement wealth and lifetime earnings. [source] Ab initio chemical kinetics for the NH2 + HNOx reactions, part II: Kinetics and mechanism for NH2 + HONOINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 11 2009Shucheng Xu The kinetics and mechanism for the reaction of NH2 with HONO have been investigated by ab initio calculations with rate constant prediction. The potential energy surface of this reaction has been computed by single-point calculations at the CCSD(T)/6-311+G(3df, 2p) level based on geometries optimized at the CCSD/6-311++G(d, p) level. The reaction producing the primary products, NH3 + NO2, takes place via precomplexes, H2N,,,c -HONO or H2N,,,t -HONO with binding energies, 5.0 or 5.9 kcal/mol, respectively. The rate constants for the major reaction channels in the temperature range of 300,3000 K are predicted by variational transition state theory or Rice,Ramsperger,Kassel,Marcus theory depending on the mechanism involved. The total rate constant can be represented by ktotal = 1.69 × 10,20 × T2.34 exp(1612/T) cm3 molecule,1 s,1 at T = 300,650 K and 8.04 × 10,22 × T3.36 exp(2303/T) cm3 molecule,1 s,1 at T = 650,3000 K. The branching ratios of the major channels are predicted: k1 + k3 producing NH3 + NO2 accounts for 1.00,0.98 in the temperature range 300,3000 K and k2 producing OH + H2NNO accounts for 0.02 at T > 2500 K. The predicted rate constant for the reverse reaction, NH3 + NO2 , NH2 + HONO represented by 8.00 × 10,26 × T4.25 exp(,11,560/T) cm3 molecule,1 s,1, is in good agreement with the experimental data. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 678,688, 2009 [source] Kinetics of the gas-phase reactions of chlorine atoms with CH2F2, CH3CCl3, and CF3CFH2 over the temperature range 253,553 KINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 6 2009E. J. K. Nilsson Relative rate techniques were used to study the title reactions in 930,1200 mbar of N2 diluent. The reaction rate coefficients measured in the present work are summarized by the expressions k(Cl + CH2F2) = 1.19 × 10,17T2 exp(,1023/T) cm3 molecule,1 s,1 (253,553 K), k(Cl + CH3CCl3) = 2.41 × 10,12 exp(,1630/T) cm3 molecule,1 s,1 (253,313 K), and k(Cl + CF3CFH2) = 1.27 × 10,12 exp(,2019/T) cm3 molecule,1 s,1 (253,313 K). Results are discussed with respect to the literature data. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 401,406, 2009 [source] Kinetics and mechanism of the hydrolytic disproportionation of iodineINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 11 2004Krisztina Seb, k-Nagy Kinetics of the hydrolytic disproportionation of I2 was studied by UV,VIS spectrophotometry at 298 K and at the ionic strength 0.2 M (NaClO4) in buffered solutions in the pH range 8.91,10.50 at different initial iodide concentrations. The characterization of this reaction is fundamental for modeling oscillatory and front reactions in the presence of iodine as reactant or intermediate as well as for drinking water treatment. A matrix rank analysis confirmed three absorbing species in the beginning of the reaction, whereas later assumption of two species is enough to describe the experimental data in the visible part of the spectrum. A reaction mechanism was proposed for disproportionation by using fitting/simulation with a multipurpose program package ZiTa, by simultaneous evaluation of 17,906 points in 79 experimental curves. A parameter set was suggested, which was obtained by absolute, relative, and orthogonal fittings of the experimental data. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 36: 596,602, 2004 [source] Kinetics and mechanism for the H-for-X exchange process in the H + C6H5X reactions: A computational studyINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 11 2001I. V. Tokmakov The addition of H atoms to benzene and toluene and subsequent transformations were investigated using high level ab initio and density functional theory methods. Molecular structures and vibrational frequencies calculated at the B3LYP/6-311++G(d,p) level of theory were used in combination with adjusted G2M energetic parameters for RRKM rate constant calculations. Standard heats of formation for cyclohexadienyl and cyclohexadienyl, 6-methyl radicals calculated through isodesmic reactions amounted to 49.5 ± 2 and 42.9 ± 3 kcal/mol, respectively. Rate constants for various elementary reactions involved in the H-for-X exchange (X = D, CH3) were calculated and closely correlated with the available experimental kinetic data. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 633,653, 2001 [source] Spatially adaptive color filter array interpolation for noiseless and noisy dataINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 3 2007Dmitriy Paliy Abstract Conventional single-chip digital cameras use color filter arrays (CFA) to sample different spectral components. Demosaicing algorithms interpolate these data to complete red, green, and blue values for each image pixel, to produce an RGB image. In this article, we propose a novel demosaicing algorithm for the Bayer CFA. For the algorithm design, we assume that, following the concept proposed in (Zhang and Wu, IEEE Trans Image Process 14 (2005), 2167,2178), the initial interpolation estimates of color channels contain two additive components: the true values of color intensities and the errors that are considered as an additive noise. A specially designed signal-adaptive filter is used to remove this so-called demosaicing noise. This filter is based on the local polynomial approximation (LPA) and the paradigm of the intersection of confidence intervals applied to select varying scales of LPA. This technique is nonlinear and spatially-adaptive with respect to the smoothness and irregularities of the image. The presented CFA interpolation (CFAI) technique takes significant advantage from assuming that the original data is noise-free. Nevertheless, in many applications, the observed data is noisy, where the noise is treated as an important intrinsic degradation of the data. We develop an adaptation of the proposed CFAI for noisy data, integrating the denoising and CFAI into a single procedure. It is assumed that the data is given according to the Bayer pattern and corrupted by signal-dependant noise common for charge-coupled device and complementary-symmetry/metal-oxide semiconductor sensors. The efficiency of the proposed approach is demonstrated by experimental results with simulated and real data. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 105,122, 2007 [source] | |||||||||||||||||||||||||||||||||||||