bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Dynamical Simulation of the Community Atmosphere Model Version 3 (CAM3)
Authors: Hurrell James W. , Hack James J. , Phillips Adam S. , Caron Julie , Yin Jeffrey 
Published: June 2006

Abstract
The dynamical simulation of the latest version of the Community Atmosphere Model (CAM3) is examined, including the seasonal variation of its mean state and its interannual variability. An ensemble of integrations forced with observed monthly varying sea surface temperatures and sea ice concentrations is compared to coexisting observations. The most significant differences from the previous version of the model [Community Climate Model version 3 (CCM3)] are associated with changes to the parameterized physics package. Results show that these changes have resulted in a modest improvement in the overall simulated climate; however, CAM3 continues to share many of the same biases exhibited by CCM3.
At sea level, CAM3 reproduces the basic observed patterns of the pressure field. Simulated surface pressures are higher than observed over the subtropics, however, an error consistent with an easterly bias in the simulated trade winds and low-latitude surface wind stress. The largest regional differences over the Northern Hemisphere (NH) occur where the simulated highs over the eastern Pacific and Atlantic Oceans are too strong during boreal winter, and erroneously low pressures at higher latitudes are most notable over Europe and Eurasia. Over the Southern Hemisphere (SH), the circumpolar Antarctic trough is too deep throughout the year.
The zonal wind structure in CAM3 is close to that observed, although the middle-latitude westerlies are too strong in both hemispheres throughout the year, consistent with errors in the simulated pressure field and the transient momentum fluxes. The observed patterns and magnitudes of upper-level divergent outflow are also well simulated by CAM3, a finding consistent with an improved and overall realistic simulation of tropical precipitation. There is, however, a tendency for the tropical precipitation maxima to remain in the NH throughout the year, while precipitation tends to be less than indicated by satellite estimates along the equator.
The CAM3 simulation of tropical intraseasonal variability is quite poor. In contrast, observed changes in tropical and subtropical precipitation and the atmospheric circulation changes associated with tropical interannual variability are well simulated. Similarly, principal modes of extratropical variability bear considerable resemblance to those observed, although biases in the mean state degrade the simulated structure of the leading mode of NH atmospheric variability.
A method for dynamic subtraction MR imaging of the liver
Authors: Mainardi Luca T , Passera Katia M , Lucesoli Agnese , Potepan Paolo , Setti Ernesto , Musumeci Renato 
Published: June 2006

Abstract

Background
Subtraction of Dynamic Contrast-Enhanced 3D Magnetic Resonance (DCE-MR) volumes can result in images that depict and accurately characterize a variety of liver lesions. However, the diagnostic utility of subtraction images depends on the extent of co-registration between non-enhanced and enhanced volumes. Movement of liver structures during acquisition must be corrected prior to subtraction. Currently available methods are computer intensive. We report a new method for the dynamic subtraction of MR liver images that does not require excessive computer time.

Methods
Nineteen consecutive patients (median age 45 years; range 37–67) were evaluated by VIBE T1-weighted sequences (TR 5.2 ms, TE 2.6 ms, flip angle 20°, slice thickness 1.5 mm) acquired before and 45s after contrast injection. Acquisition parameters were optimized for best portal system enhancement. Pre and post-contrast liver volumes were realigned using our 3D registration method which combines: (a) rigid 3D translation using maximization of normalized mutual information (NMI), and (b) fast 2D non-rigid registration which employs a complex discrete wavelet transform algorithm to maximize pixel phase correlation and perform multiresolution analysis. Registration performance was assessed quantitatively by NMI.

Results
The new registration procedure was able to realign liver structures in all 19 patients. NMI increased by about 8% after rigid registration (native vs. rigid registration 0.073 ± 0.031 vs. 0.078 ± 0.031, n.s., paired t-test) and by a further 23% (0.096 ± 0.035 vs. 0.078 ± 0.031, p < 0.001, paired t-test) after non-rigid realignment. The overall average NMI increase was 31%.

Conclusion
This new method for realigning dynamic contrast-enhanced 3D MR volumes of liver leads to subtraction images that enhance diagnostic possibilities for liver lesions.
Long-Term Progestin-Only Contraceptives Result in Reduced Endometrial Blood Flow and Oxidative Stress
Authors: Hickey M. , Krikun G. , Kodaman P. , Schatz Frederick , Carati C. , Lockwood C. J. 
Published: June 2006

AbstractContext: Because of their safety and efficacy, long-term progestin-only contraceptives (LTPOCs) are well-suited for women with restricted access to health care. However, abnormal uterine bleeding (AUB) causes half of all users to discontinue therapy within 12 months. Endometria of LTPOC-treated patients display aberrant angiogenesis with abnormally enlarged, thin-walled, fragile blood vessels, inflammation, and focal hemorrhage. In this study, similar effects were observed with a new third-generation implantable LTPOC.Objective: We hypothesized that LTPOC reduces uterine and endometrial blood flow, leading to hypoxia/reperfusion, which triggers the generation of reactive oxygen species. The latter induce aberrant angiogenesis, causing AUB.Design: Endometrial perfusion was measured by laser-Doppler fluxmetry in women requesting LTPOCs. Endometrial biopsies were obtained for in vivo and in vitro experiments.Setting: The study was conducted in the Yale University School of Medicine and Family-Planning Center in Western Australia.Patients: Seven women 18 yr or older requesting implantable LTPOCs were recruited in Western Australia.Intervention: Women received etonorgestrel implants.Main Outcome: LTPOC treatment resulted in reduced endometrial perfusion and increased endometrial oxidative damage.Conclusions: We propose that LTPOCs result in hypoxia reperfusion, which leads to aberrant angiogenesis resulting in AUB.
Benzyltriphenylphosphonium Peroxodisulfate (PhCH2PPh3)2S2O8: a Mild and Inexpensive Reagent for Efficient Oxidation of Organic Compounds under Nonaqueous and Aprotic Conditions
Authors: Mohammadpoor-Baltork Iraj , Hajipour Abdol Reza , Mohammadi Hasan 
Published: June 2006

Abstract
Benzyltriphenylphosphonium peroxodisulfate is an easily prepared and stable reagent. It could be used as an oxidant under aprotic and nonaqueous conditions in organic solvents. This reagent oxidizes different classes of alcohols to carbonyl compounds, thiols to disulfides, sulfides to sulfoxides, oximes to carbonyl compounds and aromatic amines to azo compounds efficiently. α-Hydroxy carboxylic acids and phenylacetic acids undergo oxidative decarboxylation to produce carbonyl compounds.
Conformational Analysis of Oligomers of (R)-3-Hydroxybutanoic Acid in Solutions by 1H NMR Spectroscopy
Authors: Li Jun , Uzawa Jun , Doi Yoshiharu 
Published: June 2006

Abstract
Oligomers of (R)-3-hydroxybutanoic acid (3-HB) with different end groups and chain lengths have been prepared as model compounds of bacterial poly[(R)-3-hydroxybutanoate] [P(3-HB)]. They were studied in terms of their conformational behavior generated by rotation about CH2–CH bond of 3-HB units in solutions. The conformational behaviors of 3-HB oligomers were investigated in various solvents by analysis of vicinal coupling in the 500-MHz 1H NMR spectra. For all 3-HB oligomers studied in this work, 3-HB units without hydroxy group were found, in every solvent, to adopt similar conformational distributions to those of P(3-HB) polymer backbone in solutions, in which trans and gauche conformers are preferable, while the other gauche conformer is strongly disfavored. On the other hand, 3-HB units adjacent to hydroxy terminal group in 3-HB oligomers show different conformational behaviors relative to those of other 3-HB units. In non-polar organic solvents, only gauche conformer is predominant, due to the formation of an intramolecular hydrogen bond between hydroxy and carbonyl groups, while in polar organic solvents, the conformer distributions are similar to those of 3-HB units without hydroxy groups. In aqueous solution, for 3-HB units adjacent to hydroxy terminal group, the fractions of gauche conformer are still higher than those of trans conformer due to the formation of an intramolecular hydrogen bond.
High-Performance Liquid Chromatography Stationary Phases Based on π–π Electron Interaction. Aminopropyl Silica Gels Modified with Metal Phthalocyanines
Authors: Mifune Masaki , Shimomura Yuki , Saito Yutaka , Mori Yoshihiro , Onoda Midori , Iwado Akimasa , Motohashi Noriko , Haginaka Jun 
Published: June 2006

Abstract
Aminopropyl silica gels were modified with two porphyrin derivatives and five phthalocyanine derivatives. The modified silica gels were evaluated for the usefulness as high-performance liquid chromatography stationary phases for the separation of π-electron-rich polyaromatic hydrocarbons (PAHs) such as naphthalene and phenanthrene. As a result of the modification, the aminopropyl silica gels acquired a function of π–π electron interaction with PAHs. In particular, the aminopropyl silica gel modified with copper phthalocyanine (Cu-PCS) showed the strongest π–π electron interaction with PAHs. It was the most suited as a stationary phase for the separations of PAHs among the modified silica gels tested. The Cu-PCS column could be utilized for the separation of π-electron-rich compounds including medicines, mutagens, and pollutants.
Methane Hydroxylation on a Diiron Model of Soluble Methane Monooxygenase
Authors: Yoshizawa Kazunari , Ohta Takehiro , Yamabe Tokio 
Published: June 2006

Abstract
A concerted mechanism is proposed for the conversion of methane to methanol on intermediate Q of soluble methane monooxygenase (sMMO), the active species of which is considered to involve an Fe2(μ-O)2 diamond core. A hybrid density functional theory (DFT) method is used. Methane is highly activated on the dinuclear iron complex through the formation of the Q(CH4) complex, in which a four-coordinate iron plays a central role in the bonding interactions between intermediate Q and methane. An H atom abstraction via a four-centered transition state and a methyl migration via a three-centered transition state successively occur within the complex, leading to the formation of product methanol. The reaction pathway for the methane hydroxylation on the diiron complex follows the mechanism for the gas-phase reaction by the bare FeO+ complex described in a previous paper (K. Yoshizawa, Y. Shiota, and T. Yamabe, Chem. Eur. J., 3, 1160 (1997)). Our mechanism for the methane hydroxylation by sMMO is against a radical mechanism which has been widely believed to play a role in hydrocarbon hydroxylations by cytochrome P450.
Reactions of Phenyl(styryl)iodonium Tetrafluoroborate with Halide Ions
Authors: Okuyama Tadashi , Oka Hajime , Ochiai Masahito 
Published: June 2006

Abstract
Reactions of (E)-phenyl(styryl)iodonium tetrafluoroborate with chloride, bromide, and iodide ions are examined under various conditions. The products are those of substitution and elimination, involving (Z)-1-halo-2-phenylethene (2), phenylacetylene (3), and iodobenzene as main products as well as minor products of (E)-2 and 1-halo-1-phenylethene. Results of product analysis, UV absorption spectroscopy, and kinetic measurements are consistent with major pathways involving pre-equilibrium formation of halo-λ3-iodane and iodate intermediates, leading to the in-plane vinylic SN2 substitution to (Z)-2 and the intramolecular β-elimination to 3. The minor retained product (E)-2 is concluded to be formed through the vinylenebenzenium ion intermediate in 2,2,2-trifluoroethanol through the ligand coupling within the λ3-iodane intermediate in acetonitrile. 1-Bromo-1-phenylethene is considered to be derived from 3 by reaction with HBr formed during the reaction.
Fluorination of Orthothioesters through Oxidative Desulfurization–Fluorination
Authors: Furuta Satoru , Kuroboshi Manabu , Hiyama Tamejiro 
Published: June 2006

Abstract
The oxidative desulfurization-fluorination of orthothioesters of type RCH2C(SMe)3 using n-Bu4NH2F3 and 1,3-dibromo-5,5-dimethylhydantoin gave bromodifluorination products RCHBrCF2SMe in good yields. The products were converted into bromodifluoro olefins RCBr=CF2 via oxidation and thermolysis. In a similar way, the orthothioesters of type RCH(OH)C(SMe)3 or RCH(OAc)C(SMe)3 were fluorinated to afford difluoro ketones RCOCF2SMe or difluoro acetates RCH(OAc)CF2SMe, respectively. The difluoro acetates were reduced to RCH(OAc)CF2H by radical reduction. The mechanisms are discussed for difluorination accompanied by bromination or oxidation.
Reduction of Potassium Chromate By Tannins
Authors: Arakawa Hirohumi , Watanabe Norimoto , Tamura Rui , Rao Chebrolu Pulla 
Published: June 2006

Abstract
The reduction of potassium chromate has been carried out with several tannin substances, including gallic acid, pyrogallol, ethyl gallate, polygalloylglucose, and withered oak-leaf tannin. Each reaction was followed by colorimetry, EPR spectroscopy, electrochemistry, and molecular-sieve chromatography. The progress of the chromate reductions was monitored by measuring the VIS and EPR spectra as a function of time. The observed preudo-first-order reaction rate constants for Cr(III) formation were derived based on the intensities of the Cr(III) signals of the EPR spectra. Cyclic voltammograms of the simple reductants and their final Cr(III)-containing products formed from the reductions of chromate have also been measured. The formation of Cr(III)–tannin complexes was indicated by separation on a Sephadex G-25 column. The results obtained from VIS, EPR, and cyclic voltammetry were found to be mutually dependent, and showed close correlations among the data. The rate of reduction for Cr(VI) revealed the following trend: gallic acid &gt; pyrogallol &gt; ethyl gallate &gt; polygalloylglucose &gt; witheredoak-leaf tannin. The results obtained in the present study suggest that the rates of reduction for Cr(VI) in the tannins depend upon their peak oxidation potentials and stabilities for Cr(III)–tannin complexes.
Electrochemical Studies of Spinel LiMn2O4 Films Prepared by Electrostatic Spray Deposition
Authors: Nishizawa Matsuhiko , Uchiyama Takayuki , Dokko Kaoru , Yamada Kohta , Matsue Tomokazu , Uchida Isamu 
Published: June 2006

Abstract
An uniform, dense film of spinel LiMn2O4 (thickness, about 0.5 μm) was prepared by the electrostatic spray deposition method onto a Pt film electrode on Si substrate kept at 400 °C. Electrochemical properties of the LiMn2O4 film in a solution of 1 M LiClO4/propylene carbonate were studied by cyclic voltammetry and potential-step chronoamperometry. The oxidation and reduction of the film, which are accompanied by the extraction/insertion of lithium ions, proceeded almost quantitatively around 4 V vs. Li/Li+ with excellent coulombic reversibility. The apparent chemical diffusion coefficient of Li+ in Li1−xMn2O4 spinel phase varied on the order between 10−10 and 10−12 cm2 s−1 as a function of electrode potentials with minima at the potentials corresponding to the voltammetric current peaks.
High Photocurrent Quantum Yields in Short Wavelengths for Nanocrystalline Anatase-Type TiO2 Film Electrodes Compared with Those for Rutile-Type
Authors: Shiga Akira , Tsujiko Akira , Yae Shinji , Nakato Yoshihiro 
Published: June 2006

Abstract
Photoelectrochemical activity of nanocrystalline TiO2 film electrodes prepared by use of various TiO2 particles has been studied comparatively. It is confirmed that the photocurrent (or photoactivity) for anatase-type TiO2 is in general higher than that for the rutile-type. The photocurrent quantum yield (ηpc) for anatase-type TiO2 is nearly equal to that for rutile-type in long wavelengths but increases more and more with decreasing wavelength in contrast to the ηpc for rutile-type, and thus the ηpc for anatase-type becomes much higher than the ηpc for rutile-type in short wavelengths around 300 nm, indicating that the high photoactivity for anatase-type TiO2 is due to this high ηpc in short wavelengths. There are some discussions on the reasons for the high ηpc for anatase-type TiO2 in short wavelengths, including the possibility of contribution of hot electrons or holes in the TiO2 film.
Solvent Extraction of Copper(I) and Copper(II) from Aqueous Halide Solutions with Tetrabutylammonium Ions into Chloroform
Authors: Nasu Akinobu , Kato Koji , Sekine Tatsuya 
Published: June 2006

Abstract
The solvent extraction of copper(I) and copper(II) from 1 mol dm−3 Na(X, NO3), where X−is Cl−, Br−, or I−, as ion-pairs of anionic halide complexes with tetrabutylammonium ions (tba+) into chloroform was studied in the absence and presence of a reducing agent, ascorbic acid. The extraction of copper(II) with 2-thenoyltrifluoroacetone (Htta) in chloroform from these aqueous solutions was also studied. In the absence of ascorbic acid, the extraction of copper which was added as Cu2+ with tba+ was negligible from chloride and bromide solutions but tba+CuIII3− and (tba+)2CuIII42− were extracted from iodide solutions. In the presence of ascorbic acid, the extraction of tba+CuIX2− was found from all of these halide solutions. Only copper(II) was extracted with Htta from these solutions. The distribution ratio was lower when the halide concentration was higher due to formation of copper(II) complexes in the absence of ascorbic acid and it was much lower in the presence of this reducing agent due to formation of copper(I) complexes, which were stabler than the copper(II) complexes. From the extraction data with tba+ and with Htta, the formation constants of copper(I) and copper(II) halide complexes from Cu2+ in the aqueous phase as well as the extraction constants of certain complexes into the organic phase were determined. It was concluded that the dominant metal species in the aqueous phase was Cu2+ when the halide concentration was low even in the presence of the reducing agent and thus copper(I) anionic complexes were extracted into the organic phase and the molar ratio of copper(I) complex species to Cu2+ in the aqueous phase was higher at higher halide concentrations.
Infrared Spectroscopic Study of High Temperature Behavior of the Brønsted Acidic Hydroxyl Groups on Zeolites
Authors: Lee Byongjin , Kondo Junko N , Wakabayashi Fumitaka , Domen Kazunari 
Published: June 2006

Abstract
Quantitative analysis of the high-temperature behavior of the Brønsted acidic hydroxyl groups on H-ZSM-5 and H-mordenite zeolites was conducted by in situ IR spectroscopy. The integrated intensity of the Brønsted acidic hydroxyl band on H-ZSM-5 was decreased to 67% at 873 K compared with that at room temperature. This was considered to reflect the deprotonation of hydroxyls at high temperature. Attributing the decreased OH groups at high temperature region to the conversion to IR inactive dissociated species, we estimated the energy difference between the nondissociated and dissociated hydroxyls as 24 kJ mol−1 on H-ZSM-5.
Synthesis and Properties of Dihexylbithienoquinonoid Derivatives with Head-to-head, Head-to-tail, and Tail-to-tail Orientations
Authors: Higuchi Hiroyuki , Yoshida Shima , Uraki Yoshiyuki , Ojima Juro 
Published: June 2006

Abstract
2,2′-(Dihexyl-2,2′-bithienylidene-5,5′-diylidene)bis(propanedinitrile)s (dihexylbithienoquinonoid derivatives), in which two 3-hexylthiophene moieties are connected with head-to-tail (HT) and tail-to-tail (TT) orientations, were synthesized. HT bithienoquinonoid was isolated in a single form together with a small amount of its bromo derivative, similarly to the case for the head-to-head (HH) orientational isomer. On the other hand, TT isomer exhibited a peculiar feature in solution, affording an equilibrium mixture of two geometrical isomers. Electronic and electrochemical properties of these bithienoquinonoids were studied and compared with those of HH isomer. The results proved that all these bithienoquinonoid compounds possess highly polarizable and electron-acceptable properties. HH bithienoquinonoid was reduced through one two-electron transfer process, while HT and TT isomers were reduced through two one-electron transfer processes via stable radical anions to the corresponding dianions.
Studies on Active Species for Selective Catalytic Reduction of NO on Alumina-Supported Cobalt Oxide Catalysts
Authors: Nanba Tetsuya , Uemura Atsushi , Ueno Akifumi , Haneda Masaaki , Hamada Hideaki , Kakuta Noriyoshi , Miura Hiroshi , Ohfune Hitoshi , Udagawa Yasuo 
Published: June 2006

Abstract
Alumina-supported cobalt oxide catalysts were prepared by three different methods: The impregnation and sol/gel methods using either an acid or a base as a precipitant. The catalysts prepared by sol/gel methods, followed by calcination at 773 K, exhibited a significant activity for the selective catalytic reduction (SCR) of NO with propene as a reductant. The catalyst prepared by impregnation showed poor activity when it was calcined at 773 K, but exhibited enhanced activity when calcined at 1073 K. This is attributed to tiny CoAl2O4 crystallites formed during calcination of the catalyst at 1073 K. However, in sol/gel catalysts, finely-divided CoAl2O4 crystallites were formed during calcination, even at 773 K, because of the high dispersion of Co ions in the alumina support. Thus, the active species of alumina-supported cobalt oxide catalysts for SCR of NO with propene were concluded to be tiny CoAl2O4 crystallites dispersed on alumina.