bluuebunny/crossref_metadata_2025 huggingface dataset:
Do physicists need myths?
Authors: Brown Harold I.
Published: April 2006

In textbooks and popular writings physicists repeat familiar stories about the history of physics that historians have long identified as myths. Examples of remarks about Galileo and Aristotle are used to illustrate this practice. These examples lead to a discussion of several reasons why these myths might play a positive role for physicists and whether physicists can dispense with myths about the history of their field.
Electronic Confinement and Coherence in Patterned Epitaxial Graphene
Authors: Berger Claire , Song Zhimin , Li Xuebin , Wu Xiaosong , Brown Nate , Naud Cécile , Mayou Didier , Li Tianbo , Hass Joanna , Marchenkov Alexei N. , Conrad Edward H. , First Phillip N. , de Heer Walt A.
Published: April 2006

Ultrathin epitaxial graphite was grown on single-crystal silicon carbide by vacuum graphitization. The material can be patterned using standard nanolithography methods. The transport properties, which are closely related to those of carbon nanotubes, are dominated by the single epitaxial graphene layer at the silicon carbide interface and reveal the Dirac nature of the charge carriers. Patterned structures show quantum confinement of electrons and phase coherence lengths beyond 1 micrometer at 4 kelvin, with mobilities exceeding 2.5 square meters per volt-second. All-graphene electronically coherent devices and device architectures are envisaged.
The Influence of 17-Oxo- and 17-Hydroxy-16,17-secoestratriene Derivatives on Estrogen Receptor
Authors: Jovanović-Šanta Suzana , Petrović Julijana , Sakač Marija , Žakula Zorica , Isenović Esma , Ribarac-Stepić Nevena
Published: April 2006

Since many of newly synthesised D-secoestratriene derivatives showed antiestrogenic effect, with almost a total loss of estrogenic activity, we studied the effects of some of these compounds on estrogen receptors (ER), the translocation of the estrogen-ER complexes formed in presence of competing substances into the nucleus, as well as the binding of these complexes to DNA. The results of uterotrophic effects of analysed derivatives are in agreement with the influence of these compounds on activity and binding parameters of estrogen receptors. Namely, compounds that show relatively high antiestrogenic activity predominantly increaseKdand inhibit translocation to nuclei of radioactive complexes formed in their presence. On the other hand, compounds that do not significantly change binding parameters of estrogen receptors do not show antiestrogenic effect inin vivoexperiments.
Impaired mucus-bicarbonate barrier inHelicobacter pylori-infected mice
Authors: Henriksnäs Johanna , Phillipson Mia , Storm Martin , Engstrand Lars , Soleimani Manoocher , Holm Lena
Published: April 2006

To resist the harsh intrinsic milieu, several lines of defense exist in the stomach. The aim of this study was to investigate the effect of the gastric pathogen Helicobacter pylori on these mechanisms in vivo. We used FVB/N mice expressing human α-1,3/4-fucosyl transferase (producing Lewis b epitopes) and inoculated with H. pylori 1. Mice were anesthetized with isoflurane or Hypnorm-midazolam, the stomach was exteriorized, and the surface of the corpus mucosa was exposed. Mucus thickness was measured with micropipettes, juxtamucosal pH (pHjm) was measured with pH-sensitive microelectrodes, blood flow was measured with laser-Doppler flowmetry, and mRNA levels of the bicarbonate transporter SLC26A9 were quantified with real-time PCR. The increase in mucosal blood flow seen in response to luminal acid (pH 1.5) in control animals (140 ± 9% of control) was abolished in infected mice. The firmly adherent mucus layer was significantly thinner in infected mice (31 ± 2 μm) than in control mice (46 ± 5 μm), and no mucus accumulation occurred in infected mice. pHjmdecreased significantly more on exposure to luminal acid in infected mice (luminal pH 1.5, pHjm2.4 ± 0.7) than in control mice (pHjm6.4 ± 0.5). Despite reduced pHjm, SLC26A9 mRNA expression was significantly, by increased 1.9-fold, in infected mice. The reduction in pHjmby infection with H. pylori might be due to a reduced firmly adherent mucus layer, increased mucus permeability to H+, and/or inhibition of bicarbonate transport. The upregulation of SLC26A9 in H. pylori-infected epithelium might be a result of continuous inhibition of the transporter, e.g., by ammonium, a H. pylori product, which has been previously shown to inhibit SLC26A9.
Abcg5/Abcg8-independent pathways contribute to hepatobiliary cholesterol secretion in mice
Authors: Plösch Torsten , van der Veen Jelske N. , Havinga Rick , Huijkman Nicolette C. A. , Bloks Vincent W. , Kuipers Folkert
Published: April 2006

The ATP-binding cassette (ABC) half-transporters ABCG5 and ABCG8 heterodimerize into a functional complex that mediates the secretion of plant sterols and cholesterol by hepatocytes into bile and their apical efflux from enterocytes. We addressed the putative rate-controlling role of Abcg5/Abcg8 in hepatobiliary cholesterol excretion in mice during (maximal) stimulation of this process. Despite similar bile salt (BS) excretion rates, basal total sterol and phospholipid (PL) output rates were reduced by 82% and 35%, respectively, in chow-fed Abcg5−/−mice compared with wild-type mice. When mice were infused with the hydrophilic BS tauroursodeoxycholate, similar relative increases in bile flow, BS output, PL output, and total sterol output were observed in wild-type, Abcg5+/−, and Abcg5−/−mice. Maximal cholesterol and PL output rates in Abcg5−/−mice were only 15% and 69%, respectively, of wild-type values. An infusion of increasing amounts of the hydrophobic BS taurodeoxycholate increased cholesterol excretion by 3.0- and 2.4-fold in wild-type and Abcg5−/−mice but rapidly induced cholestasis in Abcg5−/−mice. Treatment with the liver X receptor (LXR) agonist T0901317 increased the maximal sterol excretion capacity in wild-type mice (fourfold), concomitant with the induction of Abcg5/ Abcg8 expression, but not in Abcg5−/−mice. In a separate study, mice were fed chow containing 1% (wt/wt) cholesterol. As expected, hepatic expression of Abcg5 and Abcg8 was strongly induced (fivefold and fourfold) in wild-type but not LXR-α-deficient ( Lxra−/−) mice. Surprisingly, hepatobiliary cholesterol excretion was increased to the same extent, i.e., 2.2-fold in wild-type mice and 2.0-fold in Lxra−/−mice, upon cholesterol feeding. Our data confirm that Abcg5, as part of the Abcg5/Abcg8 heterodimer, strongly controls hepatobiliary cholesterol secretion in mice. However, our data demonstrate that Abcg5/Abcg8 heterodimer-independent, inducible routes exist that can significantly contribute to total hepatobiliary cholesterol output.
Sex differences in regional brain response to aversive pelvic visceral stimuli
Authors: Berman Steven M. , Naliboff Bruce D. , Suyenobu Brandall , Labus Jennifer S. , Stains Jean , Bueller Joshua A. , Ruby Kim , Mayer Emeran A.
Published: April 2006

To explore sex differences in the response of seven brain regions to an aversive pelvic visceral stimulus, functional magnetic resonance images were acquired from 13 healthy adults (6 women) during 15 s of cued rectal distension at two pressures: 25 mmHg (uncomfortable), and 45 mmHg (mild pain), as well as during an expectation condition (no distension). Random-effects analyses combining subject data voxelwise found 45-mmHg pressure significantly activated the insular and anterior cingulate cortices in both sexes. In men only, the left thalamus and ventral striatum were also activated. Although all activations appeared more extensive in men, no sex difference attained significance. To explore the presence of deactivations, which are generally cancelled by more numerous activations when subjects are combined for each voxel, the number of activated voxels, number of deactivated voxels, and ratio of deactivated voxels to total voxels affected were assessed via random-effects, mixed-model analyses combining subject data at the region level. Greater insula activation in men compared with women was seen during the expectation condition and during the 25-mmHg distension. Greater deactivations in women were seen in the amygdala (25-mmHg distension) and midcingulate (45-mmHg distension). Women had a significantly higher proportion of deactivated voxels than men in all four subcortical structures during 25-mmHg distension. Greater familiarity of females with physiological pelvic visceral discomfort may have enhanced brain systems that dampen arousal networks during lower levels of discomfort.
PYY(3–36) reduces food intake and body weight and improves insulin sensitivity in rodent models of diet-induced obesity
Authors: Vrang Niels , Madsen Andreas Nygaard , Tang-Christensen Mads , Hansen Gitte , Larsen Philip Just
Published: April 2006

The gut hormone peptide YY (PYY) was recently proposed to comprise an endogenous satiety factor. We have studied acute anorectic functions of PYY(3–36) in mice and rats, as well as metabolic effects of chronic PYY(3–36) administration to diet-induced obese (DIO) mice and rats. A single intraperitoneal injection of PYY(3–36) inhibited food intake in mice, but not in rats. We next investigated the effects of increasing doses (100, 300, and 1,000 μg·kg−1·day−1) of PYY(3–36) administered subcutaneously via osmotic minipumps on food intake and body weight in DIO C57BL/6J mice. Whereas only the highest dose (1,000 μg·kg−1·day−1) of PYY(3–36) significantly reduced food intake over the first 3 days, body weight gain was dose dependently reduced, and on day 28 the group treated with 1,000 μg·kg−1·day−1PYY(3–36) weighed ∼10% less than the vehicle-treated group. Mesenteric, epididymal, retroperitoneal, and inguinal fat pad weight was dose dependently reduced. Subcutaneous administration of PYY(3–36) (250 and 1,000 μg·kg−1·day−1) for 28 days reduced body weight and improved glycemic control in glucose-intolerant DIO rats. Neither 250 nor 1,000 μg/kg PYY(3–36) elicited a conditioned taste aversion in male rats.
Bimodal distribution of vasodilator responsiveness to adenosine due to difference in nitric oxide contribution: implications for exercise hyperemia
Authors: Martin Elizabeth A. , Nicholson Wayne T. , Eisenach John H. , Charkoudian Nisha , Joyner Michael J.
Published: April 2006

To gain insight into the role of adenosine (Ado) in exercise hyperemia, we compared forearm vasodilation induced by intra-arterial infusion of three doses of Ado with vasodilation during three workloads of forearm handgrip exercise in 27 human subjects. We measured forearm blood flow (FBF) using Doppler ultrasound and mean arterial pressure (MAP) via brachial artery catheters and calculated forearm vascular conductance (FVC = FBF/MAP) during each infusion dose or workload. We found that about half of the subjects demonstrated robust vasodilator responsiveness to both Ado infusion and exercise, and the other half demonstrated blunted vasodilator responsiveness to Ado infusion compared with exercise. In 15 subjects (identified as “Ado responders”), the change in FVC above baseline was 209 ± 33, 419 ± 57, and 603 ± 75 ml·min−1·100 mmHg−1for the low, medium, and high doses of Ado, respectively, and 221 ± 35, 413 ± 54, and 582 ± 70 ml·min−1·100 mmHg−1for the low, medium, and high exercise workloads, respectively. In the other 12 subjects (identified as “Ado nonresponders”), the change in FVC above baseline was 102 ± 36, 113 ± 42, and 151 ± 54 ml·min−1·100 mmHg−1for the low, medium, and high doses of Ado, respectively ( P < 0.05 vs. Ado responders), whereas exercise hyperemia was not different from Ado responders ( P > 0.05). Furthermore, infusion of NG-monomethyl-l-arginine (l-NMMA) blunted vasodilator responses to Ado infusion only in Ado responders ( P < 0.01 vs. post-l-NMMA) and had no effect on exercise in either group. We also found differences in vasodilator responses to isoproterenol at all doses, but acetylcholine only at one dose, between Ado responders and nonresponders. We conclude that vasodilator responsiveness to Ado exhibits a bimodal distribution among human subjects involving differences in the contribution of nitric oxide to Ado-mediated vasodilation. Finally, our data support the concept that neither Ado nor nitric oxide is obligatory for exercise hyperemia.
Hyperphagia, lower body temperature, and reduced running wheel activity precede development of morbid obesity in New Zealand obese mice
Authors: Jürgens Hella S. , Schürmann Annette , Kluge Reinhart , Ortmann Sylvia , Klaus Susanne , Joost Hans-Georg , Tschöp Matthias H.
Published: April 2006

Among polygenic mouse models of obesity, the New Zealand obese (NZO) mouse exhibits the most severe phenotype, with fat depots exceeding 40% of total body weight at the age of 6 mo. Here we dissected the components of energy balance including feeding behavior, locomotor activity, energy expenditure, and thermogenesis compared with the related lean New Zealand black (NZB) and obese B6.V-Lepob/J (ob/ob) strains (11% and 65% fat at 23 wk, respectively). NZO mice exhibited a significant hyperphagia that, when food intake was expressed per metabolic body mass, was less pronounced than that of the ob/ob strain. Compared with NZB, NZO mice exhibited increased meal frequency, meal duration, and meal size. Body temperature as determined by telemetry with implanted sensors was reduced in NZO mice, but again to a lesser extent than in the ob/ob strain. In striking contrast to ob/ob mice, NZO mice were able to maintain a constant body temperature during a 20-h cold exposure, thus exhibiting a functioning cold-induced thermogenesis. No significant differences in spontaneous home cage activity were observed among NZO, NZB, and ob/ob strains. When mice had access to voluntary running wheels, however, running activity was significantly lower in NZO than NZB mice and even lower in ob/ob mice. These data indicate that obesity in NZO mice, just as in humans, is due to a combination of hyperphagia, reduced energy expenditure, and insufficient physical activity. Because NZO mice differ strikingly from the ob/ob strain in their resistance to cold stress, we suggest that the molecular defects causing hyperphagia in NZO mice are located distal from leptin and its receptor.
Gene expression and specificity in the mature zone of the lobster olfactory organ
Authors: Stepanyan Ruben , Day Kristen , Urban Jason , Hardin Debra L. , Shetty Ranjit S. , Derby Charles D. , Ache Barry W. , McClintock Timothy S.
Published: April 2006

The lobster olfactory organ is an important model for investigating many aspects of the olfactory system. To facilitate study of the molecular basis of olfaction in lobsters, we made a subtracted cDNA library from the mature zone of the olfactory organ of Homarus americanus, the American lobster. Sequencing of the 5′-end of 5,184 cDNA clones produced 2,389 distinct high-quality sequences consisting of 1,944 singlets and 445 contigs. Matches to known sequences corresponded with the types of cells present in the olfactory organ, including specific markers of olfactory sensory neurons, auxiliary cells, secretory cells of the aesthetasc tegumental gland, and epithelial cells. The wealth of neuronal mRNAs represented among the sequences reflected the preponderance of neurons in the tissue. The sequences identified candidate genes responsible for known functions and suggested new functions not previously recognized in the olfactory organ. A cDNA microarray was designed and tested by assessing mRNA abundance differences between two of the lobster's major chemosensory structures: the mature zone of the olfactory organ and the dactyl of the walking legs, a taste organ. The 115 differences detected again emphasized the abundance of neurons in the olfactory organ, especially a cluster of mRNAs encoding cytoskeletal-associated proteins and cell adhesion molecules such as 14-3-3ζ, actins, tubulins, trophinin, Fax, Yel077cp, suppressor of profilin 2, and gelsolin.
Common Genetic Variation in Five Thrombosis Genes and Relations to Plasma Hemostatic Protein Level and Cardiovascular Disease Risk
Authors: Kathiresan Sekar , Yang Qiong , Larson Martin G. , Camargo Amy L. , Tofler Geoffrey H. , Hirschhorn Joel N. , Gabriel Stacey B. , O’Donnell Christopher J.
Published: April 2006

Objective—We undertook a linkage disequilibrium (LD)–based genetic approach to investigate the hypothesis that common sequence variants in 5 thrombosis genes influence plasma hemostatic protein levels or risk of cardiovascular disease (CVD).

Methods and Results—In a reference panel, we characterized LD structure at the fibrinogen gene cluster (fibrinogen-β[FGB],FGA, andFGG), factor VII (F7), and tissue plasminogen activator (PLAT) loci. Forty-one tag single nucleotide polymorphisms (SNPs) were genotyped in 1811 unrelated Framingham Heart Study participants. There were significant associations of 9FGBSNPs with fibrinogen level (minimumP=0.002) and of 7F7SNPs and factor VII level (minimumP<0.0001). SNPs at thePLATlocus were not associated withPLATlevel. In stepwise analysis, a singleFGBvariant explained 1% of the residual variance in fibrinogen level, and 2F7SNPs together explained 10% of the residual variance in factor VII level. TwoPLAThaplotypes were associated with CVD (multivariable-adjusted globalP=0.0004).

Conclusions—A comprehensive survey of common sequence variation demonstrates thatcis-regulatory SNPs explain a modest proportion of the residual variance in circulating fibrinogen and factor VII level andPLAThaplotypes increase the risk of CVD. Additional studies are warranted to confirm the association ofPLATsequence variation and risk of CVD.
Young Adults With Family History of Coronary Heart Disease Have Increased Arterial Vulnerability to Metabolic Risk Factors
Authors: Juonala Markus , Viikari Jorma S. A. , Räsänen Leena , Helenius Hans , Pietikäinen Matti , Raitakari Olli T.
Published: April 2006

Objective—

Subjects with family history for coronary heart disease (CHD) may be more susceptible to the adverse effects of risk factors than subjects without family history. We investigated the occurrence of subclinical atherosclerosis in young adults with family history of CHD and tested the hypothesis that their arteries are more vulnerable to the proatherogenic effects of metabolic risk factors.

Methods and Results—

Carotid artery intima-media thickness (IMT), carotid artery compliance (CAC), and brachial artery flow-mediated dilation (FMD) were measured in the 21-year follow-up of the Cardiovascular Risk in Young Finns Study in 2265 white adults 24 to 39 years of age. Subjects with positive family history of CHD had greater IMT compared with those with negative history (mean±SEM; 0.600±0.006 versus 0.578±0.002 mm;
P
=0.003, respectively). No differences were observed in CAC or FMD (both
P
>0.2). The difference in IMT remained similar after adjustment with current risk factors (
P
=0.008) or childhood risk factors measured 21 years earlier (
P
=0.002). The number of metabolic risk factors (components of the NCEP metabolic syndrome) correlated more strongly with IMT in subjects with family history of CHD than those without (
P
=0.007 for interaction).

Conclusions—

Young healthy adults with family history of CHD have increased carotid IMT. This is partly explained by their increased vulnerability to metabolic risk factors.
Reducing Ryanodine Receptor Open Probability as a Means to Abolish Spontaneous Ca
2+
Release and Increase Ca
2+
Transient Amplitude in Adult Ventricular Myocytes
Authors: Venetucci L.A. , Trafford A.W. , Díaz M.E. , O’Neill S.C. , Eisner D.A.
Published: April 2006

The aim of this work was to investigate whether it is possible to remove arrhythmogenic Ca
2+
release from the sarcoplasmic reticulum that occurs in calcium overload without compromising normal systolic release. Exposure of rat ventricular myocytes to isoproterenol (1 μmol/L) resulted in an increased amplitude of the systolic Ca
2+
transient and the appearance of waves of diastolic Ca
2+
release. Application of tetracaine (25 to 50 μmol/L) decreased the frequency or abolished the diastolic Ca
2+
release. This was accompanied by an increase in the amplitude of the systolic Ca
2+
transient. Cellular Ca
2+
flux balance was investigated by integrating Ca
2+
entry (on the L-type Ca
2+
current) and efflux (on Na–Ca
2+
exchange). Isoproterenol increased Ca
2+
influx but failed to increase Ca
2+
efflux during systole (because of the abbreviation of the duration of the Ca
2+
transient). To match this increased influx the bulk of Ca
2+
efflux occurred via Na–Ca
2+
exchange during a diastolic Ca
2+
wave. Subsequent application of tetracaine increased systolic Ca
2+
efflux and abolished the diastolic efflux. The increase of systolic efflux in tetracaine resulted from both increased amplitude and duration of the systolic Ca
2+
transient. In the presence of isoproterenol, those Ca
2+
transients preceded by diastolic release were smaller than those where no diastolic release had occurred. When tetracaine was added, the amplitude of the Ca
2+
transient was similar to those in isoproterenol with no diastolic release and larger than those preceded by diastolic release. We conclude that tetracaine increases the amplitude of the systolic Ca
2+
transient by removing the inhibitory effect of diastolic Ca
2+
release.
Sociologists Engaging with Computers
Authors: Wellman Barry
Published: April 2006

This article introduces the Symposium on the History of CITASA, the Communication and Information Technologies section of the American Sociological Association, from 1988 through 2005. It traces this history from the interest of those who founded the original Microcomputing section in developing computer applications for doing sociological research and teaching. It discusses the fit of this interest with the continuing “war” in the organization of computing between computer center centralization and individually autonomous decentralization. It explains the expansion of the scope and membership of the session to encompass the sociological study of communication and information technologies.
Learning About Politics in Low-Income Communities
Authors: Lay J. Celeste
Published: April 2006

Many take for granted that children living in impoverished communities are disadvantaged on several social outcomes, including civic knowledge, because of their poverty and the circumstances that go along with this condition. However, most analyses of poor communities are conducted only in urban neighborhoods. In this article, the author examines the paradox of small-town life: On one hand, many rural areas and small towns are just as or even more impoverished than many urban neighborhoods; on the other hand, these same communities are praised as the most civically minded and politically knowledgeable places within the United States. How can two similarly poor community types produce such different outcomes? The author shows that the best explanation for these differences is the social interaction that characterizes small towns and rural areas. Political discussion within smaller towns is beneficial for adolescents'levels of political knowledge, whereas this discussion in urban areas is associated with lower levels of knowledge.
cMYB is involved in the regulation of fetal hemoglobin production in adults
Authors: Jiang Jie , Best Steve , Menzel Stephan , Silver Nicholas , Lai Mei I. , Surdulescu Gabriela L. , Spector Tim D. , Thein Swee Lay
Published: April 2006

A quantitative trait locus (QTL) controlling HbF levels has previously been mapped to chromosome 6q23 in an Asian-Indian kindred with β thalassemia and heterocellular hereditary persistence of fetal hemoglobin (HPFH). Five protein-coding genes, ALDH8A1, HBS1L, cMYB, AHI1, and PDE7B reside in this 1.5-megabase (Mb) candidate interval of 6q23. To direct sequencing efforts we compared the expression profiles of these 5 genes between 12 individuals with elevated and 14 individuals with normal HbF levels during adult erythropoiesis by real-time quantitative reverse transcription–polymerase chain reaction (RT-PCR). Two genes, cMYB and HBS1L, demonstrated simultaneous transcriptional down-regulation in individuals with elevated HbF levels. Transfection of K562 cells encoding human cDNA of cMYB and HBS1L genes showed that, although overexpression of ectopic cMYB inhibited γ-globin gene expression, overexpression of HBS1L had no effect. Low levels of cMYB were associated with low cell expansions, accelerated erythroid maturation, and higher number of macrophages in erythroid cell culture. These observations suggest that differences in the intrinsic levels of cMYB may account for some of the variation in adult HbF levels. The possible mechanism of cMYB influencing γ- to β-globin switching is discussed.
Activation of the Lutropin/Choriogonadotropin Receptor in MA-10 Cells Stimulates Tyrosine Kinase Cascades that Activate Ras and the Extracellular Signal Regulated Kinases (ERK1/2)
Authors: Shiraishi Koji , Ascoli Mario
Published: April 2006

We show that activation of the recombinant lutropin/choriogonadotropin receptor (LHR) in mouse Leydig tumor cells (MA-10 cells) leads to the tyrosine phosphorylation of Shc (Src homology and collagen homology) and the formation of complexes containing Shc and Sos (Son of sevenless), a guanine nucleotide exchange factor for Ras. Because a dominant-negative mutant of Shc inhibits the LHR-mediated activation of Ras and the phosphorylation of ERK1/2, we conclude that the LHR-mediated phosphorylation of ERK1/2 is mediated, at least partially, by the classical pathway used by growth factor receptors. We also show that the endogenous epidermal growth factor receptor (EGFR) present in MA-10 cells is phosphorylated upon activation of the LHR. The LHR-mediated phosphorylation of the EGFR and Shc, the activation of Ras, and the phosphorylation of ERK1/2 are inhibited by expression of a dominant-negative mutant of Fyn, a member of the Src family kinases (SFKs) expressed in MA-10 cells and by PP2, a pharmacological inhibitor of the SFKs. These are also inhibited, but to a lesser extent, by AG1478, an inhibitor of the EGFR kinase. We conclude that the SFKs are responsible for the LHR-mediated phosphorylation of the EGFR and Shc, the formation of complexes containing Shc and Sos, the activation of Ras, and the phosphorylation of ERK1/2.
Selective Conjugate Reduction of α,β-Unsaturated Esters and Amides via SmI2-Promoted Electron Transfer Process
Authors: Inanaga Junji , Sakai Shino , Handa Yuichi , Yamaguchi Masaru , Yokoyama Yasuo
Published: April 2006

α,β-Unsaturated esters and amides were rapidly and selectively reduced to the corresponding saturated ones under mild conditions without affecting coexisting isolated double or triple bonds by using the reduction system, SmI2-N,N-dimethylacetamide (DMA)-proton source.
Pheophorbide as Efficient Sensitizer for DNA Photocleavage. An Implication to Its Role in Photodynamic Cancer Therapy
Authors: Komiyama Makoto , Kobayashi Masami , Harada Makoto
Published: April 2006

By use of pheophorbide a as sensitizer, DNA has been efficiently cleaved on visible light irradiation either in the presence or the absence of molecular oxygen. The possibility of DNA scission by pheophorbide a in photodynamic cancer therapy is indicated.
Absolute Configurations of Iron(III) Complexes of an Enterobactin Model, a Hexapus Cyclophane with Catechol Segments
Authors: Hisaeda Yoshio , Ihara Takeshi , Ohno Teruhisa , Murakami Yukito
Published: April 2006

The absolute configuration of an iron(III) complex of N,N′,N″-tris[N-(4-ditetradecylcarbamoy1-2,3-dihydroxybenzoyl)alanyl]-2,11,20-triaza[3.3.3]paracyclophane, an enterobactin model, was subjected to change by the chirality of the alanine residues; the l-alanine residue prefers to give out the Λ-configuration, while the d-residue stabilizes the Δ-configuration.
Chromogenic Calix[4]arene
Authors: Shimizu Hiroyasu , Iwamoto Koji , Fujimoto Kiyoshi , Shinkai Seiji
Published: April 2006

A chromogenic calix[4]arene which has within a molecule both the triester moiety as a metal-binding site and the azophenol moiety as a coloration site was synthesized. This calix[4]arene showed the high Li+ selectivity.
A New Photochromic Vinylnaphthol Derivative
Authors: Uchida Manabu , Irie Masahiro
Published: April 2006

A vinylnaphthol derivative with a thiophene ring at α-position of the vinyl group underwent photochromic reaction in nonpolor solvents. The structure of the colored form, which was isolated by HPLC, was assigned to a closed-ring naphthopyran.
Stereoselective Michael Addition Reactions of Acylated Oxazolidinones to Ethyl 3-Trifluoromethylacrylate
Authors: Yamazaki Takashi , Haga Jiro , Kitazume Tomoya
Published: April 2006

Michael addition reactions of acyl oxazolidinones to ethyl 3-trifluoromethylacrylate were found to proceed smoothly with a high degree of diastereo- as well as diastereofacial selectivity at the new carbon–carbon bond.
Importance of β Phenyl Group in Ipso Substitution of Arylvinyl Cations
Authors: Kitamura Tsugio , Soda Shin-ichi , Nakamura Ichizo , Fukuda Tetsuro , Taniguchi Hiroshi
Published: April 2006

Intramolecular and intermolecular ipso substitutions of arylvinyl cations, i.e., α-[p-(2-hydroxyethoxy)phenyl]vinyl cations and α-(p-methoxyphenyl)vinyl cations, were studied with respect to the effect of the β substituent and phenyl group as the β substituent was found to exert a significant influence on the ipso substitution.
Catalyses of Fe and FeS2 on the Reaction of Di(1-naphthyl)methane
Authors: Wei Xian-yong , Ogata Eisuke , Niki Etsuo
Published: April 2006

Reactions of di(1-naphthyl)methane (DNM) over Fe and FeS2 at 300 °C were carried out to investigate the catalytic activities and selectivities of the two catalysts. Both catalysts showed high activities for the reaction of DNM but Fe catalyzed DNM hydrogenation whereas FeS2 catalyzed DNM hydrocracking. This difference can be ascribed to the presence of sulfur.
Oxidation of 5-Bromo- and 5-Fluoro-1,3-dimethyluracils by Peroxomono- and Peroxodisulfate Ions
Authors: Itahara Toshio , Nishino Akihiro
Published: April 2006

Oxidation of 5-bromo-1,3-dimethyluracil by KHSO5 gave 5,5-dibromo-6-hydroxy- and 5,5,6-trihydroxy-1,3-dimethyl-5,6-dihydrouracils and that of 5-fluoro-1,3-dimethyluracil by Na2S2O8 gave a 6,6′-dimeric product.
A Direct NMR Observation of Stilbene Dianion in Solution
Authors: Yokoyama Yukihiro , Koizumi Terutake , Kikuchi Osamu
Published: April 2006

The NMR spectra of stilbene dianion have been observed in solution. The dianions derived from cis- and trans-stilbene are identical and only one species exists in solution even at −70 °C. From the vicinal coupling constant 3Jαα′, it is concluded that the configuration around the central bond Cα–Cα′ of the dianions is not fixed at the trans-form but the rotation about the bond occurs.
Solvolysis of (Z)- and (E)-2-Ethylidene-1-adamantyl Chlorides and Mesylates. A Unique Example Showing the Greater F-Strain Effect in the Chloride than in the Mesylate
Authors: Takeuchi Ken’ichi , Ohga Yasushi , Munakata Motohiro , Kitagawa Toshikazu
Published: April 2006

The Z/E rate ratio in the trifluoroethanolysis at 25 °C of the title chlorides and mesylates are 1023 and 126, respectively, showing the greater front strain (F-strain) effect in the (Z)-chloride than in the (Z)-mesylate. The results were supported by MM2 and AM1 calculations.
A New Squalene-type Triterpene from the Woods of Eurycoma longifolia
Authors: Itokawa Hideji , Kishi Etsuko , Morita Hiroshi , Takeya Koichi , Iitaka Yoichi
Published: April 2006

A new squalene-type triterpene with cytostatic activity, named as longilene peroxide, was isolated from the woods of Eurycoma longifolia. The solution and solid forms were elucidated by spectroscopic and X-ray analysis.
Immobilization of Myoglobin in a Multilayer Film of Two-Dimensional Polymer Network
Authors: Hamachi Itaru , Fujimura Hidetoshi , Kunitake Toyoki
Published: April 2006

Myoglobin, dioxygen storage protein, was effectively entrapped without denaturation in a multilayered, two-dimensional polymer network that was prepared by using a cast film of a phosphate bilayer membrane as molecular template. The spatial orientation of Mb observed in the presence of the bilayer matrix was lost by its solvent extraction.
Fixation of Carbon Dioxide to Carbon by Catalytic Reduction over Metal Oxides
Authors: Ishihara Tatsumi , Fujita Takanori , Mizuhara Yukako , Takita Yusaku
Published: April 2006

The catalytic reduction of CO2 to carbon with hydrogen was studied on the oxide catalysts for the fixation of carbon dioxide. Carbon dioxide was reduced to carbon and carbon monoxide selectively on the oxide catalysts. The catalyst, WO3, is highly active for reducing carbon dioxide to carbon.
Electrochemical Wacker Type Reaction with a Double Mediatory System Consisting of Palladium Complex and Tri(4-bromophenyl)amine
Authors: Inokuchi Tsutomu , Ping Liu , Hamaue Fumihiro , Izawa Miyoko , Torii Sigeru
Published: April 2006

The electrochemical Wacker type oxidation of terminal olefins by using palladium chloride or palladium acetate and tri(4-bromophenyl)amine as a recyclable mediator in either a divided cell or an undivided cell afforded the corressponding methyl ketones in good yields.
Fluorescence Excitation Spectra and Quantum Yield in Vacuum Ultraviolet Photodissociation of CF3CN
Authors: Che Dock-Chil , Kasai Toshio , Ohoyama Hiroshi , Kuwata Keiji , Kono Mitsuhiko , Tabayashi Kiyohiko , Shobatake Kosuke
Published: April 2006

The fluorescence excitation spectra of CN(A,B → X) and CF3(2A′1 → 1A″2) and the quantum yield for the CN(B) radical formation were measured in the photodissociation of CF3CN in 105–135 nm. The quantum yield for the CN(B) radical formation was found to be only a few percent. The similarity in the excitation energy dependence of CN(B → X) and of CN(A → X) indicated a common dissociation mechanism via the 3s Rydberg state of CF3CN for both states.
Synthesis of Ether-linked Disaccharide and Trisaccharide Derivatives of the Type (3-5)-d-Xylan
Authors: Martin Patrick , Conan Jacques Yves , Harmouch Benali , Postel Denis , Ronco Gino , Rouch Claude , Villa Pierre
Published: April 2006

We have synthesized a series of non-glycosidically linked di- and trisaccharide monoethers of the type (3-5)-d-xylan, by a one-pot reaction between the alcohol ROH and 3,5-anhydro-l,2-O-isopropylidene-α-d-xylofuranose, in the presence of KOH and toluene-DMSO at 80 °C.
Photolysis of trans(t-N,S)-[Co{S(O)2CH2COO-S,O}(tren)]+ (t-N = tertiary amine nitrogen; tren = tris(2-aminoethyl)amine). Linkage and Geometrical Isomerization
Authors: Akhter Farooque MD , Kojima Masaaki , Yoshii Toshihito , Kashino Setsuo , Yoshikawa Yuzo
Published: April 2006

On photolysis of trans(t-N,S)-[Co{S(O)2CH2COO-S,O}(tren)]+ with visible light, both linkage isomerization (sulfinato-S to sulfinato-O) and geometrical isomerization (trans to cis) took place to yield cis(t-N,O(S))- and trans(t-N,O(S))-[Co{OS(O)CH2COO-O,O}(tren)]+ (O(S) = oxygen of sulfinate group).
Photocontrol of Micellar Structure of an Azobenzene Containing Amphiphilic Sequential Polypeptide
Authors: Higuchi Masahiro , Minoura Norihiko , Kinoshita Takatoshi
Published: April 2006

Photo-induced structural changes were observed for an aggregate composed of amphiphilic sequential polypeptides with an azobenzene moiety in the main chain. The polypeptides associated with each other and formed micelle in aqueous solution in the dark. Photo-isomerization of the azobenzene moiety of the polypeptides induced a deaggregation of the micelle, via the bending structure formation of the polypeptide at the azobenzene moiety.
Effects of the Oxide/Metal Exposed Interface on Hydrogen Permeabilities of V2O5/Cu Multilayered Films
Authors: Shirai Hiroo , Tanaka Hidenori , Sakaguchi Hiroki , Adachi Gin-ya
Published: April 2006

Hydrogen permeabilities of V2O5/Cu multilayered films having various lengths of the perimeter of the V2O5/Cu interface were investigated. Although the hydrogen permeability of the multilayered film increased with the length of the perimeter, it increased only slowly when the length of the perimeter exceeded 9.6 × 10−2 m since the hydrogen concentration of the V2O5 layer is saturated at the region near the V2O5/Cu interface.
Selective Permeation of Carbon Dioxide through Synthetic Polymeric Membranes Having Amine Moiety
Authors: Yoshikawa Masakazu , Fujimoto Kiyoshi , Kinugawa Hirokazu , Kitao Toshio , Ogata Naoya
Published: April 2006

Permeation of CO2 was investigated by using synthetic polymeric membranes having a tertiary amine moiety, 2-(N,N-dimethyl)aminoethoxycarbonyl group. Permselectivity of the present membranes for CO2 was achieved. Through the DMAEMA/AN-199 membrane, separation factor towards CO2 for CO2/N2 separation ranged from 60 to 90.
Pyrimidines as Ferromagnetic Exchange Couplers in Dinuclear Oxovanadium(IV) Complexes
Authors: Mitsubori Shin-ichi , Ishida Takayuki , Nogami Takashi , Iwamura Hiizu
Published: April 2006

The intramolecular magnetic interactions between 1/2 spins of two oxovanadium(IV) ions were studied in the complexes L[VO(hfac)2]2 (hfac = hexafluoroacetylacetonate, L = 4-methyl-, 4,6-dimethyl-, 4-amino- and unsubstitute-pyrimidines, and quinazoline). The magnetic measurements revealed that the vanadium spins were ferromagnetically coupled through the pyrimidine bridges with J/kB = 1.1–2.7 K. The intermolecular ferromagnetic interaction was found in the case of L = pyrimidine.
Preparation of Bridgehead Substituted Bicyclo[3.3.0]octane Derivatives by the BF3·OEt2-Catalyzed Rearrangement of Bicyclo[3.2.1]oct-6-en-8-ols
Authors: Hayashi Yujiro , Ushio Hiroyuki , Narasaka Koichi
Published: April 2006

6-t-Butyldimethylsilyl-7-methylthiobicyclo[3.2.1]oct-6-en-8-ol derivatives prepared from the [2+2] cycloadducts of 1-t-butyldimethylsilyl-2-methylthioacetylene and 2-cyclohexenones are rearranged by the treatment with BF3·OEt2 into two types of bicyclo[3.3.0]octane compounds, bicyclo[3.3.0]oct-3-en-2-one or 2-methylenebicyclo[3.3.0]oct-3-ene derivatives selectively, depending on the substituent at C-1 position.
In Situ Formation Process of LiCoO2 in the Molten Lithium-Potassium Carbonate Eutectic at 923 K
Authors: Yamada Kohta , Uchida Isamu
Published: April 2006

The spontaneous oxidation of Co metal in a molten (62Li + 38K)mol% carbonate mixture with an oxygen partial pressure has been characterized at 923 K. When a thin Co film electroplated on a gold substrate was immersed into the melt, the open circuit potential (OCP) decayed gradually, indicating well-defined, three potential plateaus, and the oxide films produced at each potential plateau were identified by X-ray diffraction. The surface products at the first and second plateaus were CoIIO, but the film impedance decreased rapidly at the second plateau, suggesting the formation of the lithiated CoIIO. It was found that LiCoIIIO2 was formed at the third OCP plateau (ca. −0.4 V vs.(1 : 2)O2/CO2 reference electrode) and OCP reached to the Nernst potential of oxygen electrode reaction after the completion of LiCoO2 formation.
Induced Assembly of Aromatic Rings Caused by a CH···π Interaction
Authors: Jitsukawa Koichiro , Iwai Kouji , Masuda Hideki , Ogoshi Hisanobu , Einaga Hisahiko
Published: April 2006

The bis-(N-pyridoxy-l-phenylalaninato)cobalt(III) complex exhibiting an anomalous assembly of aromatic rings around the pyridoxy 2′-methyl group has been synthesized and characterized by 1H-NMR spectroscopy and X-ray analysis. The 1H-NMR spectrum of the complex in D2O, methanol-d4 and dimethylsulfoxide-d6 revealed peculiar upfield shift in 2′-methyl group. The detailed examination of the crystal structure demonstrated that the two C–H bond vectors of 2′-methyl group were directed toward the planes of the pyridoxy pyridine and phenylalanyl benzene rings, respectively. These findings indicate the induced assembly of aromatic rings through a CH···π interaction.
Remarkable Enhancement of 7-Ethoxycoumarin O-Deethylation by Lys250, Arg251 and Lys253 Mutations of Cytochrome P450 1A2
Authors: Sato Hideaki , Shimizu Toru , Murakami Yoshinori , Hatano Masahiro
Published: April 2006

Catalytic efficiency, kcat/Km, for 7-ethoxycoumarin O-deethylation was remarkably enhanced up to 6-fold by mutations at Lys250, Arg251 or Lys253 in cytochrome P450 1A2, while that for methanol hydroxylation was not changed by the same mutations. It is thus suggested that this ionic site is located at or near one of the hydrophobic substrate-interacting sites of this enzyme.
New Linear-Type Tetranuclear Complex, [{Cp*Rh(μ-SMe)3Mo(O)2}2(μ-O)] (Cp* = η5-C5Me5)
Authors: Xi Rimo , Wang Bateer , Ozawa Yoshiki , Abe Masaaki , Isobe Kiyoshi
Published: April 2006

A mixed metal tetranuclear complex with two MoVI(μ-SMe)3RhIII groups, [{Cp*Rh(μ-SMe)3Mo(O)2}2(μ-O)] has been obtained from the reaction of the triple-cubane type oxide cluster [(Cp*Rh)4Mo4O16] with MeSH. The complex has been characterized by X-ray analysis and variable-temperature 1H NMR spectroscopy. The latter has revealed that the complex exists as a mixture of isomers which show interconversion due to the inversion at the pyramidal sulfur center.
A Selective Synthesis of 3,5-Diphenyl-1,2,4-Oxadiazole by a Reaction of Bezylcobaloxime with Alkyl Nitrite
Authors: Kijima Masashi , Nakazato Katsuhiko , Sato Takeo
Published: April 2006

Benzyl ligand of Benzylbis(dimethylglyoximato)pyridine cobalt complexe was selectively converted to 3,5-diphenyl-1,2,4-oxadiazole by a reaction with alkyl nitrite under irradiation of visible light. The reaction proceeds via an in situ formation of an oxime and a nitrile oxide.
Partition Characteristics of Metal(II, III) Acetylacetonates between Sodium Dodecyl Sulfate Micelles and Water
Authors: Katsuta Shoichi , Saitoh Koichi
Published: April 2006

Partition coefficients of neutral acetylacetonates of Cr(III), Co(III), Rh(III), and Pd(II) between sodium dodecyl sulfate micelles and water were measured by micellar electrokinetic chromatography. The partition coefficients were much larger than those obtained between heptane and water. It was explained in terms of hydration of the complexes in the micellar phase.
Nucleophilic Substitution Reaction of Aromatic Chlorides with Cyclic Tertiary Amines under High Pressure
Authors: Ibata Toshikazu , Shang Muhong , Demura Tetsuo
Published: April 2006

The reaction of p-chloronitrobenzene with N-methylpyrrolidine under high pressure gave demethylation product and ring opening products through quaternary ammonium chloride intermediate formed by the SNAr reaction. On the other hand, the reactions with N-methylpiperidine and N-methylmorpholine gave only demethylation products. The reactions of o-chloronitrobenzene and 2,4-dichloronitrobenzene with above amines gave similar results.
A Novel and Efficient Generation of Functionalized Vinylcopper Reagents and their Reactions with Electrophiles. Synthesis of β-Methylthiobutenolides
Authors: Hojo Makoto , Harada Hajime , Hosomi Akira
Published: April 2006

Ketene dithioacetals bearing an alkoxycarbonyl group at 2-position are effectively reduced by two equimolar amounts of dimethylcuprate derived from methyllithium and cuprous cyanide to yield the corresponding functionalized vinylcopper species. These organocopper species are efficiently trapped by carbon electrophiles. Formal substitution reactions of a methylthio group in ketene dithioacetals by electrophiles can be attained by one-pot operation. Synthesis of β-thiobutenolides was also achieved.
Thermal Rearrangement of 1-Alkenyl-2-(2′,2′-diphenylethenylidene)cyclopropanes to 4-(2′,2′-Diphenylethenylidene)cyclopent-1-enes
Authors: Mizuno Kazuhiko , Sugita Hikaru , Kamada Tadashi , Otsuji Yoshio
Published: April 2006

1-Alkenyl-2-(2′,2′-diphenylethenylidene)cyclopropanes thermally rearranged to 4-(diphenylethenylidene)cyclopent-1-enes at relatively low temperature (≤373 K). Measurement of activation parameters revealed that the reactivity and mode of the reaction largely depend on structures of starting materials and products.
New Type of π-Conjugated Polymers Constituted of Quinone Units in the Main Chain
Authors: Etori Hideki , Kanbara Takaki , Yamamoto Takakazu
Published: April 2006

New π-conjugated polymers having quinone units as the recurring units, e.g., poly(2-methyl-9,10-anthraquinone-1,4-diyl) P(Me-1,4-AQ) with molecular weight of 56000, have been prepared by dehalogenation polycondensation of dichloroquinones. P(Me-1,4-AQ) exhibits unique redox behaviors due to electronic interactions between the multiple redox centers in the polymer through the π-conjugated system.
Studies on the Meerwein Arylation-Based Preparation of 2,3-Diarylbenzene-1,4-diones and Its Theoretical Interpretation
Authors: Takahashi Ichiro , Muramatsu Osamu , Fukuhara Jun , Hosokawa Yoshinao , Takeyama Naohiko , Morita Toshio , Kitajima Hidehiko
Published: April 2006

Title compounds possessing a variety of substituents are systematically prepared by means of Meerwein arylation of benzene-1,4-dione. Synthetic aspects and their MNDO calculation-based interpretation are described.
Formation and Photochemical and Thermal Reactions of Adduct between 1,2,5,3-Cobaltadithiazole and Dimethyl Acetylenedicarboxylate
Authors: Kajitani Masatsugu , Hisamatsu Naoki , Takehara Masahiro , Mori Yoshiko , Sugiyama Toru , Akiyama Takeo , Sugimori Akira
Published: April 2006

(η5-Cyclopentadienyl or η5-pentamethylcyclopentadienyl)(1-phenylmethanimine-N,1-dithiolato)cobalt(III) (1) reacts with dimethyl acetylenedicarboxylate (DMAD) to give the adducts in which Co and S of the 1,2,5,3-cobaltadithiazole ring in the cobalt complex are bridged by 1,2-dimethoxycarbonylethylene-1,2-diyl groups (3a: the complex having Cp and 3b: the complex having Cp*). The sulfur atom adjacent to N is preferentially reacted. Photolysis of 3 gives 3,4-dimethoxycarbonyl-1,2,5-cobaltadithiolene (4) with the elimination of benzonitrile. In thermolysis in benzene, 3a undergoes selectively the elimination of benzonitrile to give 4a, while 3b undergoes the elimination of either DMAD or benzonitrile to give 1 or 4.
Chiral Discrimination in the Interactions between [Co(en)3]3+ and Cholesteric Liquid Crystals by 59Co NMR Spectroscopy
Authors: Iida Masayasu , Mizuno Yuri , Koine Norio
Published: April 2006

Chiral discrimination of [Co(en)3]3+ was investigated by using 59Co NMR spectroscopy in liquid crystals comprising cesium N-dodecanoyl-l-(or d)-alaninate. The 59Co quadrupole splitting was distinguishable by diastereomeric interactions while a change in the chemical shift was the same.
N,N,N′,N′-Tetramethylazodicarboxamide (TMAD), A New Versatile Reagent for Mitsunobu Reaction. Its Application to Synthesis of Secondary Amines
Authors: Tsunoda Tetsuto , Otsuka Junko , Yamamiya Yoshiko , Itô Shô
Published: April 2006

N,N,N′,N′-Tetramethylazodicarboxamide, TMAD, was found to be more versatile in the Mitsunobu reaction than traditional diethyl azodicarboxylate or recently developed 1,1′-(azodicarbonyl)dipiperidine, when used in combination with tributylphosphine in benzene. The usefulness of the reagent was demonstrated by the highly efficient two-step synthesis of benzylcrotylamine from N-benzyltrifluoroacetamide.
A Stereoselective Synthesis of (−)-Isoiridomyrmecin. Application of the Asymmetric Aza-Claisen Rearrangement
Authors: Tsunoda Tetsuto , Tatsuki Shinji , Kataoka Kazuko , Itô Shô
Published: April 2006

(−)-Isoiridomyrmecin was synthesized stereoselectively in 6 steps starting from 1-hydroxymethyl-5-methylcyclopentene and utilizing tlle asymmetric aza-Claisen rearrangement as a key step.
Fullerene Aziridine. Facile Synthesis and Spectral Characterization of Fullerene Urethane, C60NCO2CH2CH3
Authors: Ishida Takayuki , Tanaka Kenjiro , Nogami Takashi
Published: April 2006

A fullerene urethane, C60NCO2CH2CH3, was obtained by a one-pot reaction from C60, NaN3, ClCO2CH2CH3, and 15-crown-5 ether in refluxing toluene. The structure of the product was spectroscopically determined as a closed aziridine at a 6/6-ring junction.