bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vertex Spirals in Fullerenes and Their Implications for Nomenclature of Fullerene Derivatives
Authors: Fowler Patrick W. , Horspool Daniel , Myrvold Wendy 
Published: December 2006

AbstractThe IUPAC nomenclature of fullerene derivatives is based on the vertex spiral, but not all fullerenes possess one. There are 1495 isomers with ≤20 vertices (66 isolated‐pentagon isomers with ≤150 vertices) that are vertex‐aspiral, but only four for which all vertex spiral starts succeed. Vertex‐aspiral trivalent polyhedra are common (40 190 with ≤24 vertices); infinite series include truncates of all trivalents larger than the tetrahedron. An alternative and readily automated breadth‐first‐search numbering scheme is proposed to deal with all trivalent polyhedra including fullerenes and incidentally to give robust, efficient determination of the automorphism/point group. For fullerenes, the new scheme has two clear advantages over the vertex spiral nomenclature: it is exception‐free, removing the need for complex prescriptions to deal with exceptional cases, and it is mathematically simpler in that the numbering can be found in linear rather than quadratic time (as all canonical numberings for a fullerene begin on a pentagon).
First Comprehensive Investigation of Suzuki Couplings of Alkenyl Nonaflates with Aryl and Alkenyl Boronic Acid Derivatives by Using Classical Conditions and Microwave Heating
Authors: Högermeier Jens , Reißig Hans‐Ulrich 
Published: December 2006

AbstractAlkenyl nonaflates (nonafluorobutanesulfonates) are excellent substrates in a variety of palladium‐catalysed coupling reactions. We herein demonstrate that bicyclic nonaflates generated from 8‐heterobicyclo[3.2.1]octan‐3‐one derivatives can be coupled with aryl or alkenyl boronic acids in a very efficient manner. The resulting densely functionalised bicyclic skeletons are highly suitable for further synthetic elaboration. The thermal Suzuki couplings provided the expected products in moderate to good yields. Microwave (MW) irradiation dramatically shortened reaction times and gave superior results. Bisboronic ester 19 was also coupled with bicyclic nonaflates, for example, with 14, and double Suzuki‐coupling products, such as 22, were isolated in good yields. We demonstrated the great synthetic potential of aryl‐substituted 8‐heterobicyclo[3.2.1]octene derivatives, such as 15, by the stereoselective conversion of this compound into highly substituted furanose 31 or substituted pyran derivative 33, which were obtained in short and efficient reaction sequences.
Stereoselective analysis of hydroxybupropion and application to drug interaction studies
Authors: Xu Hongmei , Loboz Katarzyna K. , Gross Annette S. , McLachlan Andrew J. 
Published: December 2006

AbstractA sensitive and stereoselective assay has been developed for the quantitation of the enantiomers of hydroxybupropion, an active metabolite of bupropion, in human plasma. The assay used liquid–liquid extraction and a Cyclobond I 2000 HPLC column with a mobile phase containing 3% acetonitrile, 0.5% triethylamine, and 20 mM ammonium acetate (pH 3.8). The technique was linear over the concentration range of 12.5–500 ng/ml for (2R,3R)‐ and (2S,3S)‐hydroxybupropion. The method was reproducible as both interday and intraday variabilities were less than 10% for both hydroxybupropion enantiomers. Overall extraction recovery of hydroxybupropion enantiomers and the internal standard phenacetin from plasma was greater than 80% and reproducible over the concentration range of 12.5–500 ng/ml for each enantiomer. The limit of quantification (LOQ) of hydroxybupropion enantiomers was 12.5 ng/ml. The stereoselective pharmacokinetics of both (2R,3R)‐ and (2S,3S)‐hydroxybupropion in healthy male subjects (n= 16) were investigated after a single dose of (rac)‐bupropion either alone or during rifampicin administration. (2R,3R)‐Hydroxybupropion was the predominant enantiomer present in plasma. A stereoselective effect of rifampicin on hydroxybupropion concentrations was observed, with rifampicin influencing the pharmacokinetics of each hydroxybupropion enantiomer in a different manner. The ratio of (2R,3R)‐hydroxybupropion (AUC0–24) to (2S,3S)‐hydroxybupropion (AUC0–24) increased from 4.9 ± 1.6 to 8.3 ± 1.9 during rifampicin administration (P< 0.001). A time‐dependent change in the hydroxybupropion enantiomeric ratio was observed after (rac)‐bupropion administration both before and during rifampicin coadministration, with an increase in the relative proportion of (2S,3S)‐hydroxybupropion over the 24 h postdose period. Chirality 19, 2007. © 2006 Wiley‐Liss, Inc.
The role of 2‐deoxy‐2‐[F‐18]fluoro‐D‐glucose positron emission tomography in disseminated carcinoma of unknown primary site
Authors: Sève Pascal , Billotey Claire , Broussolle Christiane , Dumontet Charles , Mackey John R. 
Published: December 2006

AbstractBACKGROUND.The authors conducted a comprehensive review of the efficacy of 2‐deoxy‐2‐[F‐18]fluoro‐D‐glucose positron emission tomography (FDG‐PET) in the detection of primary tumors in patients with disseminated carcinoma of unknown primary site.METHODS.Ten studies (involving a total of 221 patients) tat were published between 1998 and 2006 were reviewed. Each study evaluated the role of FDG‐PET in the detection of unknown primary tumors after a conventional diagnostic workup. Although 94% of patients had a single site of metastases, the studies otherwise were very heterogeneous in the studied population, study design, and additional diagnostic workup.RESULTS.In 41% of patients, FDG‐PET detected primary tumors that were not apparent after conventional workup. In this group of patients, the overall sensitivity, specificity, and accuracy rates of FDG‐PET in detecting unknown primary tumors were 91.9%, 81.9%, and 80.5%, respectively. FDG‐PET imaging also led to the detection of previously unrecognized metastases in 37% of patients. Lung cancers represented 59% of the detected tumors. FDG‐PET had a notably high false‐positive rate (58.3%) in tumors of the lower digestive tract. FDG‐PET altered the clinical management in 34.7% of patients. Most of those patients (53%) received specific chemotherapy for lung and pancreatic cancers; whereas 12% received specific therapy for breast, ovarian, and prostate cancers; and 14% underwent surgery with curative intent.CONCLUSIONS.FDG‐PET was an efficient method for detecting primary tumors that were undetected by other modalities and was sensitive for the detection of previously unrecognized metastases. FDG‐PET significantly changed clinical management in approximately one‐third of the patients studied. Cancer 2007. © 2006 American Cancer Society.
Steady‐state characteristics on a single‐phase buck rectifier with improved input‐current waveform
Authors: Motegi Shin‐Ichi , Maeda Akeshi 
Published: December 2006

AbstractA single‐phase buck rectifier applying pulse width modulation (PWM) creates a large amount of low‐order harmonics flow out in the input current. A high‐inductance inductor must be used to reduce the pulsations of the DC inductor current and to produce a sinusoidal input current. To address this, the authors propose a single‐phase buck rectifier with improved input current waveform by adding a switch for back flow of the DC inductor current to the conventional structural elements. In this paper, the main circuit configuration and operating theory of the proposed rectifier are explained, and its effectiveness is confirmed through experimental results and simulations. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(4): 56–65, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20330
Performance evaluation of media access control protocols using an algorithm generating graphs for effect estimation of hidden terminals
Authors: Shigeyasu Tetsuya , Matsuno Hiroshi , Morinaga Norihiko 
Published: December 2006

AbstractHidden terminals can significantly lower the throughput of such competitive MAC protocols as CSMA. Therefore, a large number of MAC protocols that implement different hidden terminal strategies have been developed. In this paper we propose an algorithm for generating evaluation networks with different ratios of hidden terminals in order to evaluate the effect of hidden terminals on competitive MAC protocols. In addition, we use the same algorithm to report results that elucidate the characteristics of throughput as the ratio of hidden terminals that exist in a network is varied for both CSMA, a representative competitive MAC protocol, and MACA, a MAC protocol that makes use of RTS/CTS control, a representative hidden terminal strategy. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 90(4): 46–55, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20343
On a construction of a nonstabilizer clifford quantum code for 2h(2j+1)‐level states
Authors: Hagiwara Manabu , Imai Hideki 
Published: December 2006

AbstractThe construction of an infinite number of nonstabilizer codes of Clifford type was given for the first time by the authors. However, the method of construction was restricted to encoding from odd prime p‐level quantum states to 2p‐level states. In this paper, the result is extended to the construction of nonstabilizer‐type quantum codes which encode quantum states of arbitrary odd 2j+1‐level to quantum states of 2h(2j+1)‐level, where h are mutually prime 2j+1. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(4): 63 – 68, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20222
Improved spectral subtraction utilizing iterative processing
Authors: Yamashita Kohei , Ogata Shin'Ya , Shimamura Tetsuya 
Published: December 2006

AbstractIn this paper, the authors propose a new noise suppression technique that executes iterative processing and sets parameters that are suited for that processing in the spectral subtraction method, which is a noise reduction technique for noise‐added speech. Iterative processing is a technique in which speech enhancement processing is executed by considering the estimated speech that is obtained when noise reduction processing is executed once as the input signal again so that a reduction of the residual noise is anticipated. A further reduction of residual noise for which speech degradation is controlled can be achieved by adjusting the parameters for each iteration. The authors also simultaneously propose a technique for maintaining the real‐time nature of spectral subtraction when the proposed technique is executed. They use actual speech to which white noise, automobile noise, and crowd babble noise is added to compare the characteristics of the two proposed methods with the conventional spectral subtraction method and its improvements. The authors verified according to objective and subjective evaluations that each proposed technique showed superior results in all noisy environments. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(4): 39 –51, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20242
Mutation spectrum in UVB‐exposed skin epidermis of Xpa‐knockout mice: Frequent recovery of triplet mutations
Authors: Ikehata Hironobu , Yanase Fumitaka , Mori Toshio , Nikaido Osamu , Tanaka Kiyoji , Ono Tetsuya 
Published: December 2006

AbstractKnockout mutations in both alleles of the Xpa gene give rise to a complete deficiency in nucleotide excision repair (NER) in mammalian cells. We used transgenic mice harboring the λ‐phage‐based lacZ mutational reporter gene to study the effect of Xpa null mutation (Xpa−/−) on damage induction, repair, and mutagenesis in mouse skin epidermis after UVB irradiation. UVB induced equal amounts of cyclobutane pyrimidine dimers (CPDs) and pyrimidine(6‐4)pyrimidone photoproducts (64PPs) in mouse skin epidermis of Xpa−/− and wild‐type mice. Neither photolesion was removed in the Xpa−/− epidermis by 12 hr after irradiation whereas removal of 64PPs was observed in the epidermis of wild‐type mice. Irradiation with 200 and 300 J/m2 UVB increased the lacZ mutant frequency in the epidermis of Xpa−/− mice, but the induced mutant frequencies were not significantly different from those previously determined for wild‐type mice. One‐hundred lacZ mutants isolated from the UVB‐exposed epidermis of Xpa−/− mice were analyzed and compared with mutant sequences previously determined for irradiated wild‐type mice. The distribution of the mutations along the lacZ transgene and the preferred dipyrimidine context of the UV‐specific mutations were similar in mutants from the Xpa−/− and wild‐type mice. The spectra of the mutations in the two genotypes were both highly UV‐specific and similar in a dominance of C → T transitions at dipyrimidine sites; however, Xpa−/− mice had a higher frequency than wild‐type mice of two‐base tandem substitutions, including CC → TT mutations, three‐base tandem mutations and double base substitutions that were separated by one unchanged base in a three‐base sequence (alternating mutations). These tandem/alternating mutations included a remarkably large number of triplet mutations, a recently reported, novel type of UV‐specific mutation, characterized by multiple base substitutions or frameshifts within a three‐nucleotide sequence containing a dipyrimidine. We conclude that the triplet mutation is a UV‐specific mutation that preferably occurs in NER‐deficient genetic backgrounds. Environ. Mol. Mutagen., 2007. © 2006 Wiley‐Liss, Inc.
Capturing temporal variability for estimates of annual hydrochemical export from a first‐order agricultural catchment in southern Ontario, Canada
Authors: Macrae M. L. , English M. C. , Schiff S. L. , Stone M. 
Published: December 2006

AbstractThis 2‐year study (2000, 2001) reports annual nutrient (phosphorus, nitrate) export from a first‐order agricultural watershed in southern Ontario based on an intensive monitoring programme. The importance of storm and melt events in annual export estimates is demonstrated and the temporal variability in nutrient loading during events is related to processes occurring within the catchment. The feasibility of predicting event‐related nutrient export from hydrometric data is explored. The importance of sampling frequency throughout events is also shown. Export of total phosphorus (TP), soluble reactive phosphorus (SRP) and nitrate ($NO_{3}^{-}$) for 2000 and 2001 averaged 0·35 kg ha−1 year−1, 0·09 kg ha−1 year−1, and 35 kg ha−1 year−1 (as N) respectively. Approximately 75% of annual TP export, 80% of annual SRP export and 70% of annual $NO_{3}^{-}$ export occurred during 28 events per year. A small number of large‐magnitude events (>34 mm) accounted for 18–42% of annual TP export, 0–61% of annual SRP export and 13–33% of annual NO$NO_{3}^{-}$ export. Our results show that temporal variability in nutrient export is largely governed by discharge in this basin, and $NO_{3}^{-}$ export can be predicted from discharge. SRP and TP export can also be predicted from discharge, but only for events that are not large in magnitude. The sampling interval throughout events is important in obtaining precise estimates of nutrient export, as infrequent sampling intervals may over‐ or under‐estimate nutrient export by ± 45% per event for P. This study improves our understanding of $NO_{3}^{-}$ and P export patterns and our ability to predict or model them by relating temporal variability in event nutrient export to discharge and processes occurring within the basin, and also by exploring the significance of sampling interval in the context of the importance of individual events, season and temporal variability during events. Copyright © 2006 John Wiley & Sons, Ltd.
The suppressive effect of myeloid elf‐1‐like factor (MEF) in osteogenic differentiation
Authors: Kim Youn‐Jeong , Kim Byung‐Gyu , Lee Seung‐Jin , Lee Ho‐Kyung , Lee Sang‐Han , Ryoo Hyun‐Mo , Cho Je‐Yoel 
Published: December 2006

AbstractMyeloid Elf‐1 like factor (MEF) is a member of the Ets transcription factor family. Ets family proteins control the expression of genes that are critical for biological processes such as proliferation, differentiation, and cell death. Some of Ets factors are also known to regulate bone development. In this study, we investigated the role of MEF in osteoblast differentiation. MEF expression was highest early in the differentiation of MC3T3‐E1 osteoblasts and was reduced by treatment with BMP‐2. The expression of MEF suppressed the alkaline phosphatase activity and expression induced by BMP‐2 stimulation and mediated by Runx2. The expression of MEF also reduces osteocalcin mRNA levels, and mineralization in MC3T3‐E1 cells. We found that the MEF‐mediated suppression of osteogenic differentiation was critically related to Runx2 regulation. The MEF and Runx2 proteins physically interact to form a complex, and this interaction interferes with Runx2 binding to the cis‐acting element OSE2 derived from the osteocalcin promoter. Co‐transfection of MEF inhibited the 6xOSE2‐luciferase reporter activity induced by Runx2. In addition, MEF stimulated the transcription of a negative mediator Msx2, and a transcriptional repressor, Mab21L1, and suppressed the transcription of a positive mediator, Dlx5 in osteoblast differentiation. MEF overexpression stimulated C2C12 cell proliferation. Together, our findings suggest that MEF promotes cell proliferation and functions as a negative regulator of osteogenic differentiation by directly interacting with Runx2 and suppressing its transcriptional activity. J. Cell. Physiol. 211: 253–260, 2007. © 2006 Wiley‐Liss, Inc.
Endothelial cell motility is compatible with junctional integrity
Authors: Guo Renyong , Sakamoto Hiroshi , Sugiura Shigeki , Ogawa Minetaro 
Published: December 2006

AbstractConfluent endothelial cells in culture are generally regarded as a model of resting endothelium in blood vessels (i.e., forming junctions at points of cell–cell contact, losing ability to proliferate in response to growth factors, and remaining stationary). However, incompatibility between junctional integrity and endothelial cell motility remains uncertain. The aim of this study was to determine whether endothelial cells (in colonies generated from differentiating embryonic stem cells in contact with OP9 stromal cell layer) have a resting endothelial phenotype (i.e., lack motility). Time‐lapse analyses showed that though endothelial cells were connected to each other through adherens junctions and tight junctions, they were moving continuously within the colonies. Endothelial cell movement was accompanied by formation of lamellipodia, which transiently accumulated green fluorescent protein‐tagged β‐actin and p41‐Arc (a subunit of the actin‐related protein 2/3 complex) at their anterior tips, suggesting that the movement is an active behavior of endothelial cells. Endothelial cell‐specific expression of yellow fluorescent protein‐tagged vascular endothelial‐cadherin and claudin‐5 revealed that adherens junctions and tight junctions persisted during endothelial cell migration. Furthermore, intercellular junctions underwent dynamic remodeling at the leading edge of moving endothelial cells. These results suggest that endothelial cells can remain highly motile without losing intercellular junctions. J. Cell. Physiol. 211: 327–335, 2007. © 2006 Wiley‐Liss, Inc.
Dopamine stimulates 45Ca2+ uptake through cAMP, PLC/PKC, and MAPKs in renal proximal tubule cells
Authors: Han Ji Yeon , Heo Jung Sun , Lee Yun Jung , Lee Jang Hern , Taub Mary , Han Ho Jae 
Published: December 2006

AbstractWe have examined the effect of dopamine on Ca2+ uptake and its related signaling pathways in primary renal proximal tubule cells (PTCs). Dopamine increased Ca2+ uptake in a concentration (>10−10 M) and time‐ (>8 h) dependent manner. Dopamine‐induced increase in Ca2+ uptake was prevented by SCH 23390 (a DA1 antagonist) rather than spiperone (a DA2 antagonist). SKF 38393 (a DA1 agonist) increased Ca2+ uptake unlike the case with quinpirole (a DA2 agonist). Dopamine‐induced increase in Ca2+ uptake was blocked by nifedipine and methoxyverapamil (L‐type Ca2+ channel blockers). Moreover, dopamine‐induced increase in Ca2+ uptake was blocked by pertussis toxin (a Gi protein inhibitor), protein kinase A (PKA) inhibitor amide 14/22 (a PKA inhibitor), and SQ 22536 (an adenylate cyclase inhibitor). Subsequently, dopamine increased cAMP level. The PLC inhibitors (U 73122 and neomycin), the PKC inhibitors (staurosporine and bisindolylmaleimide I) suppressed the dopamine‐induced increase of Ca2+ uptake. SB 203580 (a p38 MAPK inhibitor) and PD 98059 (a MAPKK inhibitor) also inhibited the dopamine‐induced increase of Ca2+ uptake. Dopamine‐induced p38 and p42/44 MAPK phosphorylation was blocked by SQ 22536, neomycin, and staurosporine. The stimulatory effect of dopamine on Ca2+ uptake was significantly inhibited by the NF‐κB inhibitors SN50, TLCK, and Bay 11‐7082. In addition, dopamine significantly increased the level of NF‐κB p65, which was prevented by either SQ 22536, neomycin, staurosporine, PD 98059, or SB 203580. Thus, dopamine stimulates Ca2+ uptake in PTCs, initially through by Gs coupled dopamine receptors, PLC/PKC, followed by MAPK, and ultimately by NF‐κB activation. J. Cell. Physiol. 211: 486–494, 2007. © 2006 Wiley‐Liss, Inc.
An improved sample preparation for an LC method used in the age estimation based on aspartic acid racemization from human dentin
Authors: Yekkala Raja , Meers Carine , Hoogmartens Jos , Lambrichts Ivo , Willems Guy , Van Schepdael Ann 
Published: December 2006

AbstractThe determination of age on the basis of aspartic acid (Asp) racemization in teeth is one of the most reliable and accurate methods to date. In this paper, the usefulness of HPLC coupled with fluorescence detection for determination of Asp racemization was evaluated. A modified sample preparation is proposed for better stability of o‐phthaldialdehyde‐N‐acetyl‐L‐cysteine derivatives of D/L‐Asp (due to the instability below pH 7). To ensure the accuracy of the method, the validation parameters' specificity, precision, linearity, and LOD were determined. Three dentin samples of premolar teeth, extracted from living individuals (bucco‐lingual longitudinal sections of 1 mm thickness), were analyzed and quantitative results are discussed.
Validation of theory of n‐column separations with gas chromatograms predicted by commercial software
Authors: Williamson Yuping , Davis Joe M. 
Published: December 2006

AbstractA probability theory for the average number of compounds resolved by the partial separation of complex mixtures on n columns was tested using commercial‐software predictions of gas chromatograms. Such n‐column separations are traditional means for addressing peak overlap, in which one chooses additional columns of different selectivity to separate compounds that cannot be separated by a single column. Gas chromatograms of five types of complex mixtures containing from 99 to 283 compounds were predicted for eight stationary phases using both optimized and other temperature programs. The number n of columns for different mixtures varied from 2 to 5. The numbers of compounds separated as singlet peaks at different resolution thresholds were compared to predictions, as evaluated with point‐process statistical‐overlap theory based on a Poisson distribution. A good agreement between theory and results was found in all cases corresponding to low saturation. Both good and poor agreements were found for cases corresponding to high saturation. A good agreement also was found for results based on resolving complex mixtures by a single column subject to two temperature programs. The moments and distribution of the number of resolved compounds were computed by Monte Carlo simulation, thus gauging the significance of departures between results and theory. The potential of such simulations to explore the limitations of theory was briefly investigated.