bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of cigarette smoke-induced inflammatory and mucus hypersecretory changes in rat lung and the role of CXCR2 ligands in mediating this effect
Authors: Stevenson Christopher S. , Coote Kevin , Webster Ruth , Johnston Helinor , Atherton Hazel C. , Nicholls Andrew , Giddings June , Sugar Rosemary , Jackson Alan , Press Neil J. , Brown Zarin , Butler Keith , Danahay Henry
Published: November 2004

Repetitive, acute inflammatory insults elicited by cigarette smoke (CS) contribute to the development of chronic obstructive pulmonary disease (COPD), a disorder associated with lung inflammation and mucus hypersecretion. Presently, there is a poor understanding of the acute inflammatory mechanisms involved in this process. The aims of this study were to develop an acute model to investigate temporal inflammatory changes occurring after CS exposure. Rats were exposed to whole body CS (once daily) generated from filtered research cigarettes. Initial studies indicated the generation of a neutrophilic/mucus hypersecreting lung phenotype in <4 days. Subsequent studies demonstrated that just two exposures to CS (15 h apart) elicited a robust inflammatory/mucus hypersecretory phenotype that was used to investigate mechanisms driving this response. Cytokine-induced neutrophil chemoattractants (CINCs) 1–3, the rat growth-related oncogene-α family homologs, and IL-1β demonstrated time-dependent increases in lung tissue or lavage fluid over the 24-h period following CS exposure. The temporal changes in the neutrophil chemokines, CINCs 1–3, mirrored increases in neutrophil infiltration, indicative of a role in neutrophil migration. In addition, a specific CXCR2 antagonist, SB-332235, effectively inhibited CS-induced neutrophilia in a dose-dependent manner, supporting this conclusion. This modeling of the response of the rat airways to acute CS exposure indicates 1) as few as two exposures to CS will induce a phenotype with similarities to COPD and 2) a novel role for CINCs in the generation of this response. These observations represent a paradigm for the study of acute, repetitive lung insults that contribute to the development of chronic disease.
Effect of an Essential Oil Mouthrinse, with and without Fluoride, on Plaque Metabolic Acid Production and pH after a Sucrose Challenge
Authors: Zhang J.Z. , Harper D.S. , Vogel G.L. , Schumacher G.
Published: November 2004

This clinical study evaluated the effect of rinsing with an essential oil-containing antiseptic mouthrinse, with or without 100 mg/kg fluoride ion, on the plaque metabolic acid production and plaque pH response after a sucrose challenge. This observer-blind, randomized study used a three-way crossover design. Twenty-four subjects rinsed with 20 ml of one of the following rinses: (1) essential oil (EO) mouthrinse, (2) essential oil mouthrinse plus 100 mg/kg fluoride, or (3) negative control, for 30 s, twice daily for 16 days. On day 17, 1 h after the last mouthrinse, subjects rinsed with 20 ml of mass fraction 10% sucrose solution for 1 min. Seven minutes after the sucrose challenge, supragingival plaque was collected from molar and premolar teeth. Plaque pH and metabolic acid ions were analyzed using a micro pH electrode and capillary electrophoresis, respectively. The results showed that after EO mouthrinse dental plaque produced 36% less lactate, 36% less acetate and 44% less propionate than after the negative control rinse. The dental plaque also exhibited a pH 0.42 unit higher after EO rinse than after the negative control rinse. These results were not affected by the addition of 100 mg/kg fluoride to the EO mouthrinse. From these results we concluded that this EO antiseptic mouthrinse, with or without fluoride ion, is effective in reduction of plaque acidogenicity after a sucrose challenge.
Action of Fluoroquinolones and Linezolid on Logarithmic- and Stationary-Phase Culture of Mycobacterium tuberculosis
Authors: García-Tapia A. , Rodríguez J.C. , Ruiz M. , Royo G.
Published: November 2004

Background: The new challenges involved in the chemotherapy of tuberculosis make it necessary to find novel drugs, especially ones that are useful in the latent phase of the disease. Methods: We evaluated the activity of linezolid and fluoroquinolones against logarithmic- and stationary-phase Mycobacterium tuberculosis. Results: We observed that linezolid exhibits antibacterial action, although slowly, in both situations. Quinolones with an 8-methoxy group exhibit greater activity than levofloxacin in logarithmic growth phases, whereas levofloxacin exhibits greater activity in stationary-phase growth. Conclusion: The study of the activity of drugs against the M. tuberculosis microorganism in the latent phase is one of the most important tools available in the fight against the tuberculosis epidemic, and both linezolid and the new fluoroquinolones appear to be promising drugs.
In vitro Antimicrobial Activity of Gatifloxacin Compared with Other Quinolones against Clinical Isolates from Cancer Patients
Authors: Rolston Kenneth V.I. , Vaziri Irfan , Frisbee-Hume Susan , Streeter Harriet , LeBlanc Barbara
Published: November 2004

Owing to the predominance of gram-positive pathogens in neutropenic cancer patients, newer generation quinolones with an expanded gram-positive spectrum and enhanced potency, may have a role to play for prophylaxis and/or empiric therapy in such patients. The in vitro activity of gatifloxacin was compared with that of ciprofloxacin, levofloxacin and trovafloxacin against 848 recent clinical isolates from cancer patients. Against gram-positive organisms, gatifloxacin was the most active agent tested inhibiting all Aerococcus, Listeria monocytogens, Micrococcus, Stomatococcus mucilaginous, Bacillus, and Rhodococcus equi strains at ≤2 mg/l, its designated susceptibility breakpoint. It was also very active against methicillin-susceptible staphylococci and Streptococcus spp. (including penicillin nonsusceptible Streptococcus pneumoniae and viridans streptococci). It had moderate activity against methicillin-resistant staphylococci and Enterococcus faecalis, inhibiting 68–80% of these strains at ≤2 mg/l. Gatifloxacin also had good activity against the Enterobacteriaceae (although ciprofloxacin was more potent) inhibiting >95% of isolates at ≤1 mg/l. Nonfermentative gram-negative organisms were less susceptible to all 4 agents. Gatifloxacin was very active against Acinetobacter lwoffi (MIC100 0.12 mg/l) and had moderate activity against Acinetobacter baumanii, Chryseobacterium spp., Stenotrophomonas maltophilia, Pseudomonas aeruginosa and other Pseudomonas species. Alcaligenes xylosoxidans strains were relatively resistant to all 4 agents.
Neonatal TSH Levels as an Index of Iodine Sufficiency: Differences Related to Time of Screening Sampling and Methodology
Authors: Gruñeiro-Papendieck Laura , Chiesa Ana , Mendez Virginia , Bengolea Sonia , Prieto Laura
Published: November 2004

Introduction: Current WHO guidelines consider that under adequate iodine intake <3% of newborns should have neonatal TSH levels of >5 mU/l blood when screening is performed in cord blood or at 3 days to 3 weeks of age. Objective: To estimate whether this absolute criterion when applied to newborns older than 48 h of age and native to Buenos Aires coincides with the traditional ones (goiter and urinary iodine in school-age children (SAC)), and if the evaluation varies with either the methodology used for TSH measurements and/or the time of specimen sampling. Population and Methods: TSH was measured by an immunofluorometric assay (IFMA) on filter paper blood spots of 186 cord blood samples, 112 babies <48 h of age and 1,500 newborns >48 h of age, and by immunoradiometric assay (IRMA) in 238 newborns. The WHO ICCIDD absolute criteria were applied to each population. Thyroid volume was assessed by direct palpation in 500 SAC, and in 100 of them urinary iodine levels were measured. Results: TSH levels were >5 mU/l blood in 11.3% of the cord blood samples and in 3.6% of the samples from babies <48 h of age, suggesting mild iodine deficiency. TSH was >5 mU/l in 2.7% of newborns >48 h of age tested by IFMA (iodine sufficient) and in 30% measured by IRMA (moderate iodine insufficiency). Median urinary iodine and goiter prevalence in SAC were 143 µg/l and 4.5%, respectively, as expected in an iodine-sufficient area. Conclusion: The TSH levels in Buenos Aires conform with the WHO criterion that defines iodine sufficiency. Application of this criterion, however, to cord blood samples or samples from babies <48 h old and the use of different methodologies may lead to erroneous conclusions.
Decorin Deficiency Leads to Impaired Angiogenesis in Injured Mouse Cornea
Authors: Schönherr Elke , Sunderkötter Cord , Schaefer Liliana , Thanos Solon , Grässel Susanne , Oldberg Åke , Iozzo Renato V. , Young Marian F. , Kresse Hans
Published: November 2004

Small leucine-rich proteoglycans play important roles in the organization of the extracellular matrix as well as for the regulation of cell behavior; two biological processes that are essential for angiogenesis. We investigated consequences of the targeted ablation of decorin (DCN), biglycan (BGN) and fibromodulin (FMOD) genes on inflammation-induced angiogenesis in the cornea. In wild-type mice, DCN was localized exclusively to the corneal stroma, while FMOD and BGN were more prominently expressed in epithelial cells. Endothelial cells from limbus blood vessels expressed BGN and FMOD, but no DCN. However, after induction of angiogenesis by chemical cauterization, DCN was expressed in the newly formed capillaries, together with BGN and FMOD. Notably, in DCN-deficient mice, the growth of vessels was significantly diminished, whereas it did not significantly change in FMOD- or BGN-deficient animals. Moreover, blood vessels of DCN-deficient mice exhibited a similar expression level of BGN as control mice, while FMOD was increased on day 3 after injury. These results indicate that DCN, in addition to its effects on fibrillogenesis, plays a regulatory role in angiogenesis and that FMOD in endothelial cells may be able to partially substitute for DCN.
Natural Saline-Flush Is Sufficient to Maintain Patency of Immobilized-Urokinase Double-Lumen Catheter Used to Provide Temporary Blood Access for Hemodialysis
Authors: Kaneko Yoshikatsu , Iwano Masako , Yoshida Hitomi , Kosuge Miyoko , Ito Sanae , Narita Ichiei , Gejyo Fumitake , Suzuki Masashi
Published: November 2004

Background: Thrombotic occlusion is a frequent complication of central venous catheters used to provide temporary blood access on hemodialysis therapy. Heparin-lock is conventionally used to maintain patency of the catheter, but the necessity of heparin-lock has not been determined yet. Methods: After the immobilized-urokinase double-lumen central venous catheter was inserted into 48 Japanese hemodialysis patients, 22 patients randomized to the heparin group received a 20-ml saline-flush, followed by 2 ml of 1,000 U/ml heparin-lock, and 26 patients randomized to the saline group received only the 20-ml saline-flush once a day for each lumen. Results: Thrombotic occlusion was observed in only 1 out of 22 patients in the heparin group and 1 out of 26 patients in the saline group. No significant difference of the catheter survival was observed between the two groups (p = 0.8599). Conclusions: Natural saline-flush is sufficient for maintaining the patency of an immobilized-urokinase double-lumen central venous catheter.
The Essential Connection Between the Two Parts of the Work of Jacques Ellul
Authors: Vanderburg Willem H.
Published: November 2004

Almost without exception, interpretations of Jacques Ellul’s work focus either on his sociopolitical thought or on his Christian reflections. However, each one drives the other, thereby exposing how we collectively journey through time and reality on amagic carpet of myths (in the sense of cultural anthropology). Ellul challenges us to give up these myths and face the relational character of our being in the world, which leads to an iconoclasm and a need for genuine reference points for life. Turning this into a theoretical system of any kind (be it sociopolitical, philosophical, or theological) is a negation of life and an invitation to a new totalitarianism.
Induction and Inhibition of Diapause by the Same Photoperiod: Experimental Evidence for a “Double Circadian Oscillator Clock”
Authors: Spieth Hubert R. , Xue Fangsen , Strau Katharina
Published: November 2004

On the southern Iberian Peninsula, the seasonal life history of the large white butterfly, Pieris brassicae, comprises 2 different photoperiodically induced developmental arrests: a hibernation diapause at photophases < 11 h and an estivation diapause at photophases > 14 h. At intermediate photophases (12 h to 13 h), the butterfly responds with a nondiapause. Combined with the experimental setup to determine photosensitivity in insects, the different photoperiodic responses at long-, intermediate-, and short-night conditions were examined to gain more insight into the time measurement mechanism in P. brassicae. The study reveals evidence for a “double circadian oscillator clock” mechanism that is based on 2 submechanisms, a “short-night determining system” and a separate “long-night determining system.” This conclusion was drawn from the facts that an LD 9:15 long-night induces a hibernation diapause but inhibits an estivation diapause and, conversely, that an LD 16:8 short-night inhibits a hibernation diapause but induces an estivation diapause. This opposite effect of the same photoperiod supports the argument for the existence of 2 independent targets for light-dark cycles, interpreted as 2 antagonistic time measurement systems. The existence and independence of 2 systems was further shown by differences in long-night versus short-night responses regarding photosensitivity, temperature dependence, and heritable factors. The long-night measurement system is most effective in the 5th larval stage, is highly affected by temperature, and is easy to manipulate by selective inbreeding. The short-night measurement system is most effective in the 4th larval stage, is largely temperature compensated, and is not affected by experimental manipulation of the longnight measurement system.
A Percolation Approach for Investigating the Sol-Gel Phase Transition of κ-Carrageenan: A Steady-State Fluorescence Study
Authors: Tari Ö. , Pekcan Ö.
Published: November 2004

A steady-state fluorescence technique was employed to study sol-gel transitions in K-carrageenan systems at various carrageenan concentrations. Scattered light, Isc, and fluorescence intensity, I, were monitored against temperature to determine critical phase transition temperatures and exponents. Pyranine was used as a fluorescence probe to monitor these phase transitions. It was observed that coil-to-helix (sol-gel) transition temperatures, Tch, strongly correlated with carrageenan concentration. The weight average degree of polymerization, DPw and gel fraction G, exponents (γ and β) were measured and found to be in accord with the classical Flory-Stockmayer model.
Evaluation of Dendritic Gadolinium Complexes as MRI Contrast Agents
Authors: Yan Guo-Ping , Bottle Steven E. , Zhuo Ren-Xi , Wei Li , Liu Mai-Li , Li Li-Yun
Published: November 2004

A series of dendritic gadolinium complexes based on dendrimers with 1,4,7,10-tetraazacyclododecane as the core were synthesized. Both diethylenetriaminepentaacetic acid and pyridoxamine were incorporated to the amine groups on the surface to give the dendritic ligands. These dendritic ligands were then reacted with gadolinium chloride to yield the corresponding dendritic gadolinium complexes. The dendritic ligands and their gadolinium complexes were characterized by 1HNMR, IR, UV and elemental analysis. Relaxivity studies showed that the dendritic gadolinium complexes have higher relaxation effectiveness than that of the clinically used small molecular gadolinium complexes. Magnetic resonance imaging of the liver in rats indicated that the dendritic gadolinium complex containing pyridoxamine enhances the image contrast of the liver, provides prolonged intravascular duration and produces highly contrasted visualization of blood vessels in the liver.
Perspectives on Modification of Aliphatic Polyesters by Radiation Processing
Authors: Södergård Anders
Published: November 2004

Aliphatic polyesters have been studied mainly for medical applications, but also for other uses. Although the properties of different aliphatic polyesters are broad, there is a need for modifications to achieve desired material properties. Plasma modification of polymers has been applied to surface modification of polymers, while the bulk of the polymer remains unchanged. High energy radiation induced processing is an established technique that is used in polymer science. Radiation is used to initiate radical polymerizations and for modifications such as degradation, cross-linking, and graft-copolymerization. In this paper article radiation processing of aliphatic polyesters is reviewed. Included are synthetic polyesters, like polyglycolide, polylactide, poly(ε-caprolactone), poly(lactide-co-caprolactone) and two commonly occurring bacterial polyesters, polyhydroxybutyrate and poly(hydroxybutyrate- co-valerate). Relevant processing parameters as well as the effects and applications of the radiation modification are presented.
New Contact Lens Based on Chitosan/Gelatin Composites
Authors: Xin-Yuan Shi , Tian-Wei Tan
Published: November 2004

A series of chitosan/gelatin composite films were prepared by solvent evaporation and characterized for oxygen permeability, optical transmittance, water absorptivity and mechanical properties. The results indicate that the introduction of gelatin was beneficial to increasing water absorption and that oxygen and solute permeability of chitosan composite film was improved. Chitosan/gelatin composite films are more permeable, transparent, flexible and biocompatible films and could potently be used for contact lens material.
The expression Of Cultural Sensitivity in the Presence of African Americans
Authors: Akiba Daisuke , Miller Fayneese
Published: November 2004

This study explores the motivational factors underlying European American individuals’ tendency to display more culturally sensitive behavior in the presence of African Americans. European American male college students (N = 75) individually viewed and evaluated racially insensitive humor, ostensibly in small groups with two confederates. The confederates’ racialbackgrounds were varied so that they consisted of either (a)two European Americans, (b) one European American and one African American, or (c) two African Americans. Half of the participants in each condition reacted to the humor privately, whereas the other half responded to the humor publicly. It was revealed that the mere perception of the presence of an African American individual prompted participants to display cultural sensitivity, evaluating the anti-African American humor negatively. It was interesting that this tendency was equally prevalent when participants rated the humor publicly and when they rated it privately. Implications for understanding the nature of cultural sensitivity and interracial self disclosure are discussed.
The Effects of National Culture and Anonymity on Flaming and Criticalness in GSS-Supported Discussions
Authors: Reinig Bruce A. , Mejias Roberto J.
Published: November 2004

Technologies for supporting collaborative work are often developed to improve various aspects of group performance such as idea generation and decision quality; however, less attention has been given to the effects that such technology has upon the nature of group communication. In this article, we examine the phenomena of flaming and comment criticalness in computer-mediated communication as they occur in group support systems (GSS) supported discussions. A 2 X 2 factorial experimental design was used to examine the effects of national culture (U.S. and Hong Kong) and anonymity (identified and anonymous pen name) on the number of comments classified as flames and on the number of comments classified as critical in 39 GSS discussions. Experimental results indicate that both national culture and anonymity influence the number of critical comments occurring in such discussions. However, the findings were not significant with respect to the number of comments categorized as flames.
Chemotherapy-Associated Oxidative Stress: Impact on Chemotherapeutic Effectiveness
Authors: Conklin Kenneth A.
Published: November 2004

Antineoplastic agents induce oxidative stress in biological systems. During cancer chemotherapy, oxidative stress-induced lipid peroxidation generates numerous electrophilic aldehydes that can attack many cellular targets. These products of oxidative stress can slow cell cycle progression of cancer cells and cause cell cycle checkpoint arrest, effects that may interfere with the ability of anticancer drugs to kill cancer cells. The aldehydes may also inhibit drug-induced apoptosis (programmed cell death) by inactivating death receptors and inhibiting caspase activity. These effects would also diminish the efficacy of the treatment. The use of anti-oxidants during chemotherapy may enhance therapy by reducing the generation of oxidative stress-induced aldehydes.
Ultrafast Intramolecular Electron Transfer in Peripherally Ruthenated Zinc Tetraarylporphyrins
Authors: Wall Mark H , Akimoto Seiji , Yamazaki Tomoko , Ohta Nobuhiro , Yamazaki Iwao , Sakuma Takuya , Kido Hiroaki
Published: November 2004

Ultrafast fluorescence quenching has been examined for 5-pyridyl-10,15,20-triphenylporphinatozinc (ZnP), which is coordinatively linked to ruthenium complex (oxo-acetatobridged-triruthenium ions) (Ru), and for its derivatives having cyanopyridyl groups (Ru1) or 4-(N,N-dimethylamino)pyridyl groups (Ru2). The fluorescence for these peripherally elaborated zinc tetraarylporphyrins are > 99% quenched relative to ZnP. Fluorescence decays were measured in different solvents using the technique of femtosecond fluorescence up-conversion for these three compounds: ZnP–Ru+, ZnP–Ru+–Ru1+, and ZnP–Ru+–Ru2+. The fluorescence lifetime for ZnP* (τf = 1.7—1.8 ns in ZnP monomer) is dramatically decreased by the linkage of ruthenium moieties to the periphery of ZnP; τf = 460—530 fs for ZnP*–Ru+, τf = 380—400 fs for ZnP–Ru+–Ru1+, and τf = 300—380 fs for ZnP–Ru+–Ru2+. This fluorescence quenching behavior is in accord with a semiempirical estimation of the free energy for electron transfer from ZnP* to Ru+. Thus the ultrafast fluorescence quenching process in these molecules is attributed to an intramolecular electron transfer governed by the following equations: ZnP*–Ru+ → ZnP+–Ru0 and ZnP*–Ru+–Ru1+ (or Ru2+) → ZnP+–Ru0–Ru1+ (or Ru2+).
Tetradecyltrimethylammonium Bromide + Dodecyltrimethylammonium Bromide Mixed Micelles in Aqueous Glycol Oligomers
Authors: Bakshi Mandeep Singh , Kaur Ushwinder
Published: November 2004

The conductances of tetradecyltrimethylammonium bromide (TTAB) + dodecyltrimethylammonium bromide (DTAB) mixtures over the entire mole fraction range of TTAB (αTTAB) were measured in pure water as well as in the presence of various aqueous ethylene glycol oligomers containing 5 and 10 wt% of each additive in their respective binary mixtures at 30 °C. From the conductivity data, the critical micellar concentrations (cmc) and degrees of micelle ionization (χ) for TTAB + DTAB mixtures were computed. From the slopes of the conductivity curves, the equivalent conductivities of the monomeric (Λm), monomeric in the presence of additive (Λm,a) and the micelle (Λmic) state were calculated, the results are discussed with respect to the glycol-additive effects in the whole mole fraction range of the binary mixture. The micellar parameters of both surfactants and of their mixtures show a significant dependence on the amount in comparison to the number of repeating units of glycol oligomers. These results have been explained on the basis of the medium effects of aqueous additive, which are drastically influenced by the increase in the amount of additive rather than by the increase in the number of repeating units. The non-ideality in TTAB + DTAB mixtures was evaluated by using the regular solution theory and Motomura’s formulation based on the excess thermodynamic quantities. It has been found that the regular solution interaction parameter (β) and micellar mole fraction () remain almost unaffected even in the presence of up to 10 wt% of each additive and molecular weight 4000. These results suggest that there are no significant interactions between the glycol oligomers and the micelles of single and mixed surfactants.
Analysis of Electrolysis Reactions of Metal Complexes Using On-Line Electrospray Ionization Mass Spectrometry with a Compact Electrolytic Flow-Through Cell
Authors: Arakawa Ryuichi , Abura Tsutomu , Fukuo Tsuyoshi , Horiguchi Hironobu , Matsubayashi Gen-etsu
Published: November 2004

An on-line electrospray ionization mass-spectrometric analysis for an electrolysis reaction was developed by the installation of a compact, efficient flow-through cell upstream of an electrospraying needle. The electrode was designed to avoid any reduction of the oxidation products formed during electrolysis. The electrolytic oxidation reaction of a Ru and Os metal complex was carried out to examine the performance of the system. From the electrolysis of [M(bpy)3](PF6)2 (where M = Ru and Os, and bpy = 2,2′-bipyridine) we detected the one-electron oxidation product, [M(bpy)3]3+. The electrolysis of [Ru(bpy)2(en)](ClO4)2 (en = ethylenediamine) formed two complex products along with the elimination of two and four hydrogen atoms from the en ligand. The structure of the two complex products was determined to be a monoimine and diimine complex, based on an electrolysis experiment using a deuterium-labeled complex, [Ru(bpy)2(ed)](ClO4)2 (ed = ethylene-d4-diamine, H2N–CD2–CD2–NH2). The results indicate that electrochemical oxidation occurs at the ethylenediamine ligand and that the monoimine complex is a reaction intermediate for the formation of a diimine complex.
Stereochemical Study of a Lewis Acid-Promoted Reaction of 2-Silyloxypyrrole with Aliphatic and Aromatic Aldehydes
Authors: Uno Hidemitsu , Nishihara Yasuaki , Mizobe Noboru , Ono Noboru
Published: November 2004

In the presence of BF3·OEt2, the reaction of 1-t-butoxycarbonyl-2-t-butyldimethylsiloxypyrrole with aliphatic and aromatic aldehydes in ether occurred stereoselectively to give the corresponding erythro and threo isomers, respectively, while a similar reaction in the presence of SnCl4showed completely opposite selectivity. The transition states leading to the major isomers are discussed.
Scandium Trifluoromethanesulfonate-Catalyzed Cleavage of Esters Bearing a Coordinative Group at a Vicinal Position
Authors: Kajiro Hiroshi , Mitamura Shuichi , Mori Atsunori , Hiyama Tamejiro
Published: November 2004

Scandium trifluoromethanesulfonate is found to be a Lewis acid catalyst for selective cleavage of esters containing a coordinative group adjacent to an ester moiety. The reaction proceeds under weak acidic conditions at room temperature; the catalyst can be recovered and reused. Even α-acyloxy ketones are deacetylated without racemization. Selective monodeacetylation at C-10 of paclitaxel has been achieved.
Ni-Promoted Syntheses of New 3,3′-Dichloro-5,5′-bipyrazoles and Poly(bipyrazole-5,5′-diyl)s and Isolation of Nickel Complexes Relevant to the Syntheses
Authors: Murakami Yasuharu , Yamamoto Takakazu
Published: November 2004

Reactions of 3,5-dichloropyrazoles and 3,3′-dichloro-5,5′-bipyrazoles with zerovalent nickel complex, Ni(0)Lm, have been studied. In cases of 3,5-dichloro-1,4-dimethylpyrazole and 3,5-dichloro-4-methoxycarbonyl-1-methylpyrazole, only the C(5)–Cl bond of the two C–Cl bonds reacts with Ni(0)Lm to afford novel bis(pyrazolyl)nickel(II) complexes with the intact C(3)–Cl bond in moderate yields. Treatment of the bis(pyrazolyl)nickel(II) complexes with H2SO4 gives the new dichloro monomers: 3,3′-dichloro-1,1′,4,4′-tetramethyl-5,5′-bipyrazole and its 4,4′-bis(methoxycarbonyl) analogue. These undergo dehalogenative polycondensation to give poly(1,1′,4,4′-tetramethyl-5,5′-bipyrazole-3,3′-diyl) (6) and its 4,4′-bis(methoxycarbonyl) analogue (7), respectively. Polymer 6 is soluble in formic acid, and gives an intrinsic viscosity of 39 cm3 g−1 in formic acid, whereas polymer 7 is soluble in various organic solvents and has an Mn value of 8800 (Mw/Mn = 1.56) as estimated from GPC. They show photoluminescent peaks at the onset position of the respective π–π* absorption bands.
Photophysical and Photochemical Primary Processes of Diphenylacetylene Derivatives and Related Compounds in Liquid Phase
Authors: Hirata Yoshinori
Published: November 2004

Photophysical and photochemical primary processes of diphenylacetylene (DPA) derivatives and related compounds have been reviewed. Curious photophysical properties of the low lying excited singlet states of DPA, such as an exceptionally slow S2 → S1 internal conversion, a distinct temperature effect of the S2 lifetime, and a strong excitation energy dependence of the fluorescence yield, were correlated with the S2–S1 energy gap. Contradictions of the assignments of the lowest excited singlet states of DPA were resolved and the mechanism of the S2 → S1 internal conversion was proposed from the comparison of the dynamic behavior of DPA with that of diphenylpolyenes. The small S2–S1 energy gap as well as the large displacement between the potential curves of the upper and lower electronic states can be a reason why the S2 state of the DPA derivatives is exceptionally long-lived. The DPA derivatives of which the intramolecular charge-separated states are formed in polar solvents were used as probe molecules of the solvent–solute interaction. Significant enhancement of the charge recombination of aminophenyl(phenyl)acetylene in protic solvents should be due to the interaction between amino nitrogen atom of the solute molecule and the hydrogen-bonded solvent oligomer.
The Chemistry of Germanium-Containing Heavy Ketones
Authors: Tokitoh Norihiro , Matsumoto Tsuyoshi , Okazaki Renji
Published: November 2004

The recent applications of an extremely bulky and efficient steric protection group, 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (denoted as Tbt in this article), to the kinetic stabilization of a series of doubly bonded compounds between germanium and heavier chalcogen atoms (we coin the expression “germanium-containing heavy ketones” for this family of heavier congeners of germanone) are described. Combination of a Tbt group with some other bulky aromatic or alkyl substituent enabled us to synthesize the novel germanium-containing double-bond species [Tbt(R)Ge=X; R = 2,4,6-triisopropylphenyl (Tip) or bis(trimethylsilyl)methyl (Dis)] such as germanethiones (X = S), germaneselones (X = Se), and germanetellones (X = Te) as stable crystalline compounds, while the germanone [Tbt(Tip)Ge=O], the most reactive species among the germanium-containing heavy ketones, was found to be very difficult to isolate and was evidenced only by the trapping reactions. The X-ray crystallographic analysis of the isolated germanium-containing heavy ketones revealed a completely trigonal planar geometry around their germachalcogenocarbonyl units and their ideally doubly bonded character, which was also confirmed by their spectroscopic data.
Stereoselectivity for S-Bridged Polynuclear Transition Metal Complexes Formed by Aggregation of Octahedral Complexes to Square-Planar Palladium(II)
Authors: Okamoto Ken-ichi , Sasaki Chieko , Yamada Yasunori , Konno Takumi
Published: November 2004

Novel pentanuclear complexes, [Pd{Pd(aet)}{M(aet)2}{M(aet)3}2]4+ (M = Rh (1); Ir (2); aet = 2-aminoethanethiolate) and [Pd2{Pd(aet)2}{Co(aet)3}2]4+ (4), were prepared by the reactions of fac(S)-[M′(aet)3] (M′ = M, Co) with Na2[PdCl4]. Molecular structures for 1, 2 and 4 were determined by X-ray diffraction. In 1 and 2, two Pd atoms forming the parallel planes are spanned by the aggregation of two octahedral fac(S)-[M(aet)3] units and cis(N)-[M(S)2(aet)2] unit. In these complexes, one of the aet ligands in the starting fac(S)-[M(aet)3] transfers from the M ( = Rh, Ir) atom to the Pd one. Two Pd atoms in 4 are bridged by two fac(S)-[Co(aet)3] units and cis(S)-[Pd(aet)2] unit. In this complex, two aet ligands transfer to the Pd one. The methylation reaction for one non-bridging S atom in 1 gave the corresponding complex [Pd{Pd(aet)}{Rh(aet)(smaet}{Rh(aet)3}2]5+ (3; smaet = S-methyl-2-aminoethanethiolate), whose structure was also determined by X-ray diffraction. For all of the complexes, the chiral configurations are selectively regulated owing to the octahedral units (Δ or Λ) and the bridging sulfur atoms (R or S), and they are characterized on the basis of the electronic absorption, circular dichroism (CD) and 13C NMR spectral behavior. The binding modes of the octahedral units in 1, 2, and 4 are also discussed in relation to their stereochemical behavior.
Classification of Low-Energy Conformations of Met-Enkephalin in the Gas Phase and in a Model Solvent Based on the Extended Scaled Particle Theory
Authors: Mitsutake Ayori , Irisa Masayuki , Okamoto Yuko , Hirata Fumio
Published: November 2004

We employed Monte Carlo simulated annealing to classify the low-energy conformations of Met-enkephalin in the gas phase and in aqueous solution. In order to include the free energy of cavity formation in aqueous solution, we used the method of extended scaled particle theory. This is the first attempt to combine the Monte Carlo simulated annealing method and the extended scaled particle theory. We conducted 20 Monte Carlo simulated annealing runs of 10000 Monte Carlo sweeps both in the gas phase and in aqueous solution. It was found that the obtained conformations (20 each) can be classified into 3 groups of similar structure both in the gas phase and in aqueous solution. We studied in detail the structural characteristics of the classified conformations. It was found that the cavity-formation effects of aqueous solution do not drastically change the backbone structures obtained in the gas phase. The relation between the solvent-accessible surface area and the cavity-formation free energy was studied in detail. The results show unambiguously that the cavity-formation free energy is not neccessarily proportional to the accessible surface area, at least for a small peptide.
Structure Analyses of Two Crystal Forms of Paroxetine Hydrochloride
Authors: Yokota Masaaki , Uekusa Hidehiro , Ohashi Yuji
Published: November 2004

Two crystal forms of (−)-trans-4-(p-fluorophenyl)-3-(3,4-methylenedioxyphenoxymethyl)piperidine hydrochloride salt (paroxetine HCl) have been analyzed by X-rays. One form (Form I) is obtained as a hemihydrate and the other (Form II) is crystallized as the propan-2-ol solvate. The crystal of Form I belongs to the monoclinic system and the space group is P21. The unit-cell dimensions are; a = 14.5888(10), b = 10.1591(7), c = 13.0255(10) Å, β = 107.095(3)°, and V = 1845.2(2) Å3. There are two crystallographically independent protonated paroxetine molecules with different conformations and chloride anions, and one water molecule in an asymmetric unit. The crystal of Form II also belongs to the monoclinic system and the space group is P21. The unit-cell dimensions are; a = 11.6504(7), b = 5.7374(3), c = 16.4107(10) Å, β = 90.959(2)°, and V = 1096.79(11) Å3. There are one protonated paroxetine molecule, one chloride anion, and one solvent propan-2-ol molecule in an asymmetric unit. The protonated paroxetine molecule in Form II has a different conformation from those in Form I. The solvent propan-2-ol molecule is disordered in the channel formed by paroxetine molecules and chloride anions. The crystal was easily decomposed in open air at room temperature because the propan-2-ol molecules are easily released through the channel.
X-Ray Structural Analyses of Rare Earth Trifluoromethanesulfonate Complexes Bearing Urea Derivatives
Authors: Nishiura Masayoshi , Okano Naoko , Imamoto Tsuneo
Published: November 2004

X-Ray structural analyses of the rare earth(III) trifluoromethanesulfonates (triflates) with urea derivatives are described. The reactions of anhydrous rare earth triflates with 8 equiv of tetrahydro-2-pyrimidinone (trimethyleneurea (PU)) in methanol give [M(pu)8](OTf)3 (OTf = triflate) (M = Sm: 1a; M = Y: 1b; M = Nd: 1c; M = Eu: 1d; M = Gd: 1e; M = Tb: 1f; M = Dy: 1g; M = Ho: 1h; M = Yb: 1i), and [Sc(pu)6](OTf)3 (2). X-Ray crystallographic analyses of these complexes indicate that a pair of PU ligands are interacting with each other through the hydrogen bonds. The reaction of anhydrous samarium(III) triflate with 6 equiv of 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (1,3-dimethyltrimethyleneurea (DMPU)) in tetrahydrofuran (THF) affords [Sm(dmpu)6](OTf)3 (3) which has a hexa-coordinated octahedral structure. Anhydrous samarium(III) triflate reacts with 5 equiv of 1,3-dimethyl-2-imidazolidinone (DMI) to give [Sm(Otf)2(dmi)5]OTf (4) which has a hepta-coordinated pentagonal bipyramidal structure. Five DMI ligands in 4 coordinate to the samarium atom in a propeller-like fashion.
Computational Studies on Chiral Discrimination Mechanism of Phenylcarbamate Derivatives of Cellulose
Authors: Yamamoto Chiyo , Yashima Eiji , Okamoto Yoshio
Published: November 2004

The calculations of interaction energies between cellulose tris(phenylcarbamate) (CTPC) or cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) and trans-stilbene oxide (1) or benzoin (2) were performed by various methods. The purpose was to gain insight into the mechanism for the chiral recognition on phenylcarbamate derivatives of cellulose which are useful chiral stationary phases for HPLC. The calculations were roughly divided into two methods: 1) Enantiomers were generated around the NH proton and the C=O oxygen of the carbamoyl group of CTPC and CDMPC which are considered to be the most important adsorption sites, and then the interaction energy was calculated. 2) Enantiomers were randomly generated by the Monte Carlo method on the surface of CTPC and CDMPC, and then the interaction energy was calculated. The results of both calculations were in good agreement with the results in the chromatographic resolution of 1 and 2 by CTPC and CDMPC.
Rotational Isomerization of (E)-(2-Anthryl)ethenes. A Consideration Why Are the s-cis Rotamers More Stable than the s-trans Rotamers in the Excited State and Less Stable in the Ground State?
Authors: Karatsu Takashi , Itoh Hajime , Yoshikawa Nobuko , Kitamura Akihide , Tokumaru Katsumi
Published: November 2004

Rotational isomerism between s-cis and s-trans rotamers of (E)-1-(2-anthryl)-2-phenylethene (E-2APE) and (E)-1-(2-anthryl)-3,3-dimethyl-1-butene (E-2ADB) were investigated by comparing the absorption, emission and transient absorption spectra with those of the model compounds. The s-trans isomer is more stable than the s-cis rotamer in the ground state; however, the s-cis isomer is more stable than the s-trans rotamer in the excited state (the lowest singlet and triplet excited state). In the triplet excited state, s–trans → s–cis one-way rotational isomerization is observed with activation energies of 30 and 18 kJ mol−1 for E-2APE and E-2ADB, respectively. Explanations of why the s-cis rotamer is more stable than the s-trans rotamer in the excited state and less stable in the ground state are proposed using the HOMO and LUMO coefficients estimated by a MOPAC93 (PM3) calculation.
Synthesis of 13C-Labeled Biosynthetic Precursor of Lipid A and Its Analogue with Shorter Acyl Chains
Authors: Oikawa Masato , Shintaku Tetsuya , Sekljic Harald , Fukase Koichi , Kusumoto Shoichi
Published: November 2004

The synthesis of regiospecifically 13C-labeled compounds of a biosynthetic precursor of lipid A and its analogue with shorter acyl chains is described. d-(6-13C)Glucose was converted into a suitably protected glucosamine derivative via 1,6-anhydro-β-d-(6-13C)glucose. After coupling with glycosyl donors, the desired compounds were synthesized through a 6-step reaction sequence. The total yields were 1.7% for the biosynthetic precursor, and 6.4% for the short acyl analogue, respectively, for a total of 18 steps from d-(6-13C)glucose.
Preparation of Primary Amines by the Alkylation of O-Sulfonyloximes of Benzophenone Derivatives with Grignard Reagents
Authors: Tsutsui Hironori , Ichikawa Tomoko , Narasaka Koichi
Published: November 2004

Primary amines are prepared by the electrophilic amination of Grignard reagents with benzophenone O-sulfonyloxime derivatives. 4,4′-Bis(trifluoromethyl)benzophenone O-sulfonyloximes react with alkyl Grignard reagents in the presence of a catalytic amount of CuCN in tetrahydrofuran-hexamethylphosphoric triamide to give N-alkylimines, which are readily hydrolyzed to primary amines. 3,3′,5,5′-Tetrakis(trifluoromethyl)benzophenone O-p-tolylsulfonyloxime is arylated to the corresponding N-arylimines with aryl Grignard reagents in ether–toluene, and hydrolysis of the resulting imines gives aniline derivatives.
Effects of Substitution of Hydrophobic Amino Acids by Tryptophan on Receptor Binding and Biological Activity of Neuropeptide Nociceptin
Authors: Okada Kazushi , Sujaku Tetsujo , Nakashima Rie , Nose Takeru , Yamada Yoshinari , Yokoyama Masayuki , Nagahisa Atushi , Shimohigashi Yasuyuki
Published: November 2004

Nociceptin is a neuropeptide that binds to and activates the opioid receptor-like ORL1 receptor. In order to explore the structural elements necessary for receptor recognition and activation, we designed and synthesized a series of nociceptin analogues, in which nonpolar amino acid residues such as Gly6, Ala7, Ala11, Leu14, and Ala15were substituted respectively by Trp. [Trp6]- and [Trp7]nociceptins exhibited rather weak activities (5—15% of nociceptin), and [Trp11]- and [Trp15]nociceptins also showed reduced activities (40—50%). These results suggested that the space available for these particular residues are relatively restricted. By contrast, the Trp/Leu-substitution at position 14 retained full receptor binding activity, and the resulting [Trp14]nociceptin exhibited an increased biological activity in the functional assay using [35S]GTPγS. This suggested that the receptor residue interacting with nociceptin-Leu14 is the aromatic amino acid.
Asymmetric Hydroformylation of Olefins in Highly Crosslinked Polymer Matrixes
Authors: Nozaki Kyoko , Shibahara Fumitoshi , Itoi Yohei , Shirakawa Eiji , Ohta Tetsuo , Takaya Hidemasa , Hiyama Tamejiro
Published: November 2004

When polymer-immobilized chiral phosphine-phosphite–Rh(I) complexes were used, the asymmetric hydroformylation of styrene gave 2- and 3-phenylpropanals with a substrate/catalyst ratio of 2000, iso/normal ratios of 84/16 to 89/11, and 89% R enantiomeric excess of 2-phenylpropanal; these results were at the highest level in catalytic activity, regio-, and enantioselectivities. Recovery-reuse of the catalyst was examined. Asymmetric hydroformylation of vinyl acetate, (Z)-2-butene, and 3,3,3-trifluoropropene was also successfully performed with the polymer-supported catalysts.
Carbonylation of Formaldehyde with Carbon Monoxide over Cation-Exchange Resin Catalysts
Authors: Wang Zheng Bao , Shimada Takashi , Takagi Hiroyuki , Ahn Cheol-Hee , Sano Tsuneji , Soga Kazuo , Takahashi Ikuo , Masuda Takashi
Published: November 2004

The carbonylation of formaldehyde with carbon monoxide was carried out over two kinds of cation-exchange resins as solid acid catalysts. Effects of reaction conditions on the catalytic performance were studied. From 1H NMR, 13C NMR, IR, and GC-MS analyses of the products obtained, it was found that 1,3-dioxolan-4-one (1,3-DOX-4) is selectively produced over the cation-exchange resins. The carbonylation of formaldehyde with carbon monoxide over the cation-exchange resins proceeds under milder reaction conditions, as compared with HZSM-5 zeolite.
Synthesis and Characterization of a Novel Green Photoluminescent Silicon-Containing Poly(p-phenylenevinylene)
Authors: Chen Zhi-Kuan , Wang Lian-Hui , Kang En-Tang , Lai Yee-Hing , Huang Wei
Published: November 2004

A novel solution processable photoluminescent polymer containing silyl groups has been successfully synthesized through a polycondensation reaction. The polymer was characterized through FT-IR, NMR, UV-vis spectroscopy, photoluminescent spectroscopy (PL), elemental analysis and cyclic voltammetry (CV). A TGA analysis shows that the polymer is stable up to 300 °C both in air and in nitrogen. The UV-vis absorption spectra for both the solution and film samples are very similar. The band gap obtained from the optical spectra is 2.53 eV. The maximum emissions of photoluminescence are at 494 and 507 nm for the solution and film samples, respectively. The UV-vis spectrum of its polymer film also shows a very small temperature dependence. A cyclic voltammogram illustrates that the polymer can be reversibly n-doped and dedoped in a negative sweep and irreversibly p-doped during a positive sweep. All of the results demonstrate that the obtained polymer is a promising green-light emission material for PLED applications.
Preparation and Properties of a New Hard Material of Composition C3N3.6-4.5O1.1-1.2H4.1-4.2
Authors: Kawaguchi Masayuki , Tokimatsu Yasuyo , Nozaki Koji , Kaburagi Yutaka , Hishiyama Yoshihiro
Published: November 2004

A new material of composition C3N3.6–4.5O1.1–1.2H4.1–4.2, which is harder than a quartz glass plate and shows ferromagnetism at room temperature, has been prepared by the reaction of C3N3Cl3 with Li3N at 220 °C.
Generation, Characterization and Some Reactions of 1,1-Ethylene-1H-azulenium Ion
Authors: Oda Mitsunori , Kajioka Takanori , Okujima Tetsuo , Itoh Shunji , Morita Noboru , Miyatake Ryuta , Kuroda Shigeyasu
Published: November 2004

The title carbocation, generated from 1,1-ethylene-1,6-dihydroazulene and trityl tetrafluoroborate in deuterated acetonitrile at −20 °C, was characterized by means of low temperature NMR spectroscopy, and was found to undergo expansion of the cyclopropane ring at elevated temperature and to react with nucleophiles to give the addition products at the cyclopropane methylene carbon.
Crystal Structure and Electrical Conducting Properties of [BEDT-BDTBT]3[ReO4]2, an Organic Conductor Based on a Novel Benzo[c]thiophene-Extended Donor
Authors: Ise Toshihiro , Mori Takehiko , Takahashi Kazuko
Published: November 2004

Conducting behavior and X-ray crystal structure of ReO4 salt of a new benzo[c]thiophene-extended donor have been investigated, revealing that the packing mode as well as the donor to anion ratio varies distinctly by changing the central hetero atom.
Novel Concurrent Formation of Mo–Si and Si–C Bonds by the Reaction between [MoH4(Ph2PCH2CH2PPh2)2] and PhSiH3
Authors: Zhou Da-Yang , Minato Makoto , Ito Takashi , Yamasaki Mikio
Published: November 2004

Reaction of [MoH4(Ph2PCH2CH2PPh2)2] with PhSiH3 in refluxing toluene yielded doubly chelated novel complexes with the Si–C–C–P–Mo framework as a result of the oxidative addition involving Si–H bond cleavage concurrent with the selective activation of the ortho C–H bonds of the dppe ligands.
Synthesis, Extraction and Enrichment of Dy Endohedral Fullerenes
Authors: Takabayashi Yasuhiro , Kubozono Yoshihiro , Hiraoka Koji , Inoue Takashi , Mimura Kazue , Maeda Hironobu , Kashino Setsuo
Published: November 2004

The Dy endohedral C60 (Dy@C60) was extracted with aniline under ultrasonic irradiation from the soot prepared by arc-heating of Dy2O3/graphite composite rod under He pressure of 80 Torr. The purification of Dy@C60 was performed by using high performance liquid chromatography (HPLC) technique. Furthermore, the Dy endohedral C82 (Dy@C82) was effectively extracted from the soot with N,N-dimethylformamide (DMF).
Fluorescence Properties of BDD Molecules Doped in Si-Ti Binary Oxide Systems by the Sol-Gel Method
Authors: Zhang Jinlong , Yamashita Hiromi , Anpo Masakazu
Published: November 2004

The characteristics of the fluorescence spectra of 2,5-bis(4-diethyl-aminophenyl)-1,3,4-oxadiazole(BDD) doped in Si-Ti binary oxides by the sol-gel method were investigated as a function of time in its transitions from sol to gel to xerogel. The characteristic BDD excimer fluorescence was observed during the transition from gel to xerogel only in a mixture of TEOS and TPOT but not in pure TEOS, indicating that the presence of a tetrahedrally coordinated titanium ion species plays a significant role in the formation of the excimer.