bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of the hASCT2-binding domain of the Env ERVWE1/syncytin-1 fusogenic glycoprotein
Authors: Cheynet Valérie , Oriol Guy , Mallet François
Published: August 2006

The cellular HERV-W envelope/syncytin-1 protein, encoded by the envelope gene of the ERVWE1 proviral locus is a fusogenic glycoprotein probably involved in the formation of the placental syncytiotrophoblast layer. Syncytin-1-induced in vitro cell-cell fusion is dependent on the interaction with hASCT2. As no receptor binding domain has been clearly defined in the SU of neither the HERV-W Env nor the retroviruses of the same interference group, we designed an in vitro binding assay to evaluate the interaction of the HERV-W envelope with the hASCT2 receptor. Using truncated HERV-W SU subunits, a region consisting of the N-terminal 124 amino acids of the mature SU glycoprotein was determined as the minimal receptor-binding domain. This domain contains several sub-domains which are poorly conserved among retroviruses of this interference group but a region of 18 residus containing the SDGGGX2DX2R conserved motif was proved to be essential for syncytin-1-hASCT2 interaction.
Candidate polyanion microbicides inhibit HIV-1 infection and dissemination pathways in human cervical explants
Authors: Fletcher Patricia S , Wallace Gregory S , Mesquita Pedro MM , Shattock Robin J
Published: August 2006

Background

Heterosexual intercourse remains the major route of HIV-1 transmission worldwide, with almost 5 million new infections occurring each year. Women increasingly bear a disproportionate burden of the pandemic, thus there is an urgent need to develop new strategies to reduce HIV-1 transmission that could be controlled by women themselves. The potential of topical microbicides to reduce HIV transmission across mucosal surfaces has been clearly identified, and some agents are currently under evaluation in clinical trials. Many of these "first generation" microbicides consist of polyanionic compounds designed to interfere with viral attachment. Here we have evaluated two candidate polyanion compounds in clinical trials, PRO 2000 and dextrin sulphate (DxS) to determine their safety and efficacy against in vitro HIV-1 and HSV-2 infection using cellular and tissue explant models.

Results

PRO 2000 and DxS potently inhibited infection by HIV-1 X4 and R5 isolates when present during viral exposure. However PRO 2000 required 10-fold and DxS 2000-fold more compound to block infection with R5 virus than X4. While both compounds were virucidal for X4 HIV-1, neither was virucidal for R5 virus. PRO 2000 efficiently inhibited infection of cervical explants and dissemination of virus by migratory DC. DxS was less active, able to completely inhibit cervical explant infection, but providing only partial reduction of virus dissemination by DC. PRO 2000, but not DxS, also inhibited HIV-1 binding to DC-SIGN+ cells and trans infection of co-cultured target cells. The inflammatory potential of both compounds was screened by measurement of cytokine production from cervical explants, and statistically significant increases were only observed for IL-1β and RANTES following treatment with PRO 2000. Both compounds also demonstrated potent activity against HSV-2 infection of cervical epithelial cells.

Conclusion

Our results demonstrate that PRO 2000 is a potent inhibitor of R5 HIV-1 infection and dissemination pathways in human cervical explants. DxS, while demonstrating significant inhibition of R5 infection, was less active against DC mediated dissemination pathways. PRO 2000 has now entered human phase III efficacy trials.
Role of scavenger receptor MARCO in macrophage responses to CpG oligodeoxynucleotides
Authors: Józefowski Szczepan , Sulahian Timothy H , Arredouani Mohamed , Kobzik Lester
Published: August 2006

The macrophage Class A scavenger receptor MARCO (macrophage receptor with a collagenous structure) functions as a pattern-recognition receptor for bacterial components, but its role in responses to CpG oligonucleotide sequences (CpG-ODN) in microbial DNA has not been characterized. Phosphorothioate (PS)-linked CpG-ODN stimulated IL-12 and NO production in wild-type but not in MARCO-deficient, thioglycollate-elicited peritoneal macrophages. MARCO and the related class A receptor SR-A belong to a redundant system of receptors for PS ODNs. The ability of MARCO to bind CpG-ODNs and conversely, to costimulate IL-12 and NO production upon specific ligation with immobilized mAb is consistent with MARCO being a signaling receptor for CpG-ODNs, costimulating TLR9-mediated NO and IL-12 production in macrophages. In contrast to MARCO, SR-A is likely to mediate negative regulation of macrophage responses to CpG-ODNs. In particular, increased affinity toward SR-A may contribute to decreased potency of oligo G-modified CpG-ODNs in stimulating IL-12 production. The results suggest that differential involvement of activating and inhibitory membrane receptors, such as SR-A and MARCO, may underlie profound differences observed in biological activities of different ODN sequences.
Blood glucose testing for adults prescribed atypical antipsychotics in primary and secondary care
Authors: Tarrant Catharine Jane
Published: August 2006

Aims and Method

The routine monitoring of blood glucose indices for all patients on atypical antipsychotics in 2004 in a rural adult psychiatric sector was examined. Pragmatic and practical standards were based on consensus expert opinion, National Institute for Clinical Excellence and prescribing guidelines.

Results

The audit was completed on 60 atypical antipsychotic prescriptions. Testing of blood glucose prior to the initiation or change of an atypical antipsychotic was largely followed, with an overall adherence rate of 82%. However, there were large differences in testing between in-patient and community settings. Routine yearly monitoring in the community was inadequate, with an adherence rate of 63%.

Clinical Implications

There is a welcome emphasis on the physical health of those with severe and enduring mental illness. New initiatives, including prescribing guidelines, the care programme approach and primary care registers, offer the opportunity to develop consistency and coordination between primary and secondary care in the routine monitoring of psychiatric treatments and physical health in these patients.
Increased Risk of Breast Cancer Associated With CHEK2*1100delC
Authors: Weischer Maren , Bojesen Stig Egil , Tybjærg-Hansen Anne , Axelsson Christen Kirk , Nordestgaard Børge Grønne
Published: August 2006

Purpose

CHEK2*1100delC heterozygosity has been associated with increased risk of breast, prostate, and colorectal cancer in case-control studies. We tested the hypothesis that CHEK2*1100delC heterozygosity in the general population increases the risk of cancer in general, and breast, prostate, and colorectal cancer in particular.

Patients and Methods

We performed a prospective study of 9,231 individuals from the Danish general population, who were observed for 34 years, and we performed a case-control study including 1,101 cases of breast cancer and 4,665 controls.

Results

Of the general population, 0.5% were heterozygotes and 99.5% were noncarriers. In the prospective study, multifactorially adjusted hazard ratios by CHEK2*1100delC heterozygosity versus noncarriers were 1.2 (95% CI, 0.7 to 2.1) for all cancers, 3.2 (95% CI, 1.0 to 9.9) for breast cancer, 2.3 (95% CI, 0.6 to 9.5) for prostate cancer, and 1.6 (95% CI, 0.4 to 6.5) for colorectal cancer. In the case-control study, age-matched odds ratio for breast cancer by CHEK2*1100delC heterozygosity versus noncarriers was 2.6 (95% CI, 1.3 to 5.4). The absolute 10-year risk of breast cancer in CHEK2*1100delC heterozygotes amounted to 24% in women older than 60 years undergoing hormone replacement therapy, with a body mass index of 25 kg/m2 or higher.

Conclusion

CHEK2*1100delC heterozygosity is associated with a three-fold risk of breast cancer in women in the general population.
Low Social Support and Poor Emotional Regulation Are Associated with Increased Stress Hormone Reactivity to Mental Stress in Systemic Hypertension
Authors: Wirtz Petra H. , von Känel Roland , Mohiyeddini Changiz , Emini Luljeta , Ruedisueli Katharina , Groessbauer Sara , Ehlert Ulrike
Published: August 2006

Context: There is strong evidence for a physiological hyperreactivity to stress in systemic hypertension, but data on associated or potentially moderating psychological factors are scarce.

Objective: The objective of the study was to identify psychological correlates of physiological stress reactivity in systemic hypertension.

Design: This was a cross-sectional, quasiexperimentally controlled study. Study participants underwent an acute standardized psychosocial stress task combining public speaking and mental arithmetic in front of an audience.

Setting: The study was conducted in the population in the state of Zurich, Switzerland.

Subjects: Subjects included 22 hypertensive and 26 normotensive men (mean ± sem 44 ± 2 yr).

Main Outcome Measures: We assessed the psychological measures social support, emotional regulation, and cognitive appraisal of the stressful situation. Moreover, we measured salivary cortisol and plasma epinephrine and norepinephrine before and after stress and several times up to 60 min thereafter as well as blood pressure and heart rate.

Results: We found poorer hedonistic emotional regulation (HER) and lower perceived social support in hypertensives, compared with normotensives (P < 0.01). Compared with normotensives, hypertensives showed higher cortisol, epinephrine, and norepinephrine secretions after stress (P < 0.038) as well as higher systolic and diastolic blood pressure (P < 0.001). Cortisol reactivity and norepinephrine secretion were highest in hypertensive men with low HER (P < 0.05). In contrast, hypertensives with high HER did not significantly differ from normotensives in both cortisol and norepinephrine secretion after stress. Epinephrine secretion was highest in hypertensives with low social support but was not different between hypertensives with high social support and normotensives.

Conclusions: The findings suggest that both low social support and low HER are associated with elevated stress hormone reactivity in systemic hypertension.
Predictors of Postabsorptive Ghrelin Secretion after Intake of Different Macronutrients
Authors: Marzullo P. , Caumo A. , Savia G. , Verti B. , Walker G. E. , Maestrini S. , Tagliaferri A. , Di Blasio A. M. , Liuzzi A.
Published: August 2006

Context: Release of ghrelin, a gastrointestinal hormone regulating feeding and energy balance, is blunted in obesity, a condition associated with insulin resistance.

Objective: The objective was to identify anthropometric and metabolic predictors of postabsorptive ghrelin secretion.

Design: We evaluated ghrelin, insulin, glucose, and leptin secretion overnight and after intake of different macronutrients.

Subjects: Ten obese subjects (age, 31.8 ± 2.5 yr; body mass index, 43.4 ± 0.8 kg/m2) and six lean subjects (age, 33.5 ± 2.4 yr; body mass index, 21.8 ± 1.4 kg/m2) participated in the study.

Main Outcome Measures: The main outcome measures were resting energy expenditure (REE); fat mass; nighttime approximate entropy (ApEn) and synchronicity (cross-ApEn) of ghrelin, insulin, and leptin; insulin sensitivity by homeostatic model approach insulin-sensitivity (HOMA-S%); postabsorptive area under the curve (AUC); and Δ of ghrelin, insulin, glucose, and leptin after carbohydrate-, lipid-, and protein-rich test meals.

Results: Nighttime ApEn scores were higher in obese than lean subjects (P < 0.01). Cross-ApEn revealed a synchronicity between ghrelin-insulin, ghrelin-leptin, and insulin-leptin in both groups. Compared with baseline, ghrelin decreased significantly (P < 0.01) in lean and obese subjects after carbohydrates (42.2 vs. 28.5%; P < 0.05), lipids (40.2 vs. 26.2%; P < 0.01), and proteins (42.2 vs. 26.3%; P < 0.01) devoid of between-meal ghrelin differences. Significant associations occurred between nocturnal ghrelin ApEn and insulin (r = 0.53; P < 0.05), postmeal ghrelin AUCs and REE (r = −0.57; P < 0.05), and HOMA-S% (r = 0.52; P < 0.05), postmeal ghrelin Δ and HOMA-S% (r = 0.60; P < 0.05). REE (β = −0.57; P = 0.02) and ghrelin ApEn (β = −0.62; P = 0.01) were predictors of postmeal ghrelin AUC and Δ, respectively.

Conclusions: Obesity determined a decreased orderliness of ghrelin secretion and a relative loss of ghrelin-insulin synchrony. Postabsorptive ghrelin secretion decreased significantly both in obese and lean subjects, was related to insulin sensitivity, and was predicted by energy expenditure and hormone pulsatility.
Predictive Value of Circulating Insulin-Like Growth Factor I Levels in Ischemic Stroke Outcome
Authors: Bondanelli Marta , Ambrosio Maria Rosaria , Onofri Alessandro , Bergonzoni Antonella , Lavezzi Susanna , Zatelli Maria Chiara , Valle Domenico , Basaglia Nino , degli Uberti Ettore C.
Published: August 2006

Context: Cerebrovascular disease is highly prevalent in the general population, frequently leading to permanent invalidity and reduced quality of life. IGF-I is recognized as an important neuroprotective factor against cerebral hypoxic insult.

Objective: The objective of the study was to evaluate pituitary function, in particular GH-IGF-I axis, in adult patients receiving rehabilitation after an ischemic stroke.

Subjects and Methods: We studied 42 patients (12 females; age range, 50–88 yr) during rehabilitation after stroke, evaluating the relationship between the GH-IGF-I axis and the severity (National Institutes of Health stroke scale) and outcome [Rancho Los Amigos Scale of Cognitive Functioning (LCFS); Functional Independence Measure (FIM); modified Ranking Scale] from stroke.

Results: GH deficiency was demonstrated in five patients (11.9%). Peak GH after GHRH + arginine test and IGF-I levels did not correlate with severity of stroke. IGF-I was positively correlated with LCFS (r = 0.305, P < 0.05) and the difference between FIM on admission and at discharge from rehabilitation (ΔFIM; r = 0.361, P < 0.02). Outcome indexes (LCFS, FIM at discharge, ΔFIM) and occurrence of favorable outcome (modified Ranking Scale 0–1) were significantly (P < 0.05) higher in patients with IGF-I levels 161.8 μg/dl or greater (50th percentile of the patient distribution). LH-FSH deficiency (three cases), ACTH deficiency (one case), and hyperprolactinemia (two cases) were detected. One patient had primary hypogonadism, and six males had low testosterone with normal LH and FSH levels. By multivariate analysis, IGF-I level was the main significant predictor of ΔFIM and LCFS.

Conclusions: Ischemic stroke may be associated with pituitary dysfunction, particularly GH and gonadotropin deficiencies. The higher IGF-I levels observed in patients with better outcome suggest a possible neuroprotective role of IGF-I. Circulating IGF-I may predict functional performance during rehabilitation and ischemic stroke outcome.
Long-Term Mortality and Incidence of Renal Dialysis and Transplantation in Type 1 Diabetes Mellitus
Authors: Stadler M. , Auinger M. , Anderwald C. , Kästenbauer T. , Kramar R. , Feinböck C. , Irsigler K. , Kronenberg F. , Prager R.
Published: August 2006

Aims: We investigated long-term mortality and requirement of renal replacement therapy (RRT) in type 1 diabetes mellitus (T1DM) to study risk factors and late complication incidence of T1DM in a prospective cohort study at Lainz Hospital, Vienna, Austria.

Methods: In 1983–1984, T1DM patients [n = 648; 47% females, 53% males; age, 30 ± 11 yr; T1DM duration, 15 ± 9 yr; body mass index, 24 ± 4 kg/m2; glycated hemoglobin (HbA1c), 7.6 ± 1.6%] were stratified into HbA1c quartiles [1st, 5.9 ± 0.5% (range, 4.2–6.5%); 2nd, 6.9 ± 0.3% (6.6–7.4%); 3rd, 7.9 ± 0.3% (7.5–8.4%); and 4th, 9.6 ± 1.3% (8.5–14.8%)]. Twenty years later, both endpoints (death and RRT) were investigated by record linkage with national registries.

Results: At baseline, creatinine clearance, blood pressure, and body mass index were comparable among the HbA1c quartiles, whereas albuminuria was more frequent in the 4th quartile (+15%; P < 0.03). After the 20-yr follow-up, 13.0% of the patients had died [rate, 708 per 100,000 person-years (95% confidence interval, 557–859)], and 5.6% had received RRT [311 per 100,000 person-years (95% confidence interval, 210–412)]. Patients with the highest HbA1c values (4th quartile) had a higher mortality rate and a greater incidence of RRT (P < 0.04). In the Cox proportional hazards analysis, age, male gender, increased HbA1c, albuminuria, and reduced creatinine clearance were predictors of mortality (P < 0.05). Predictors of RRT were albuminuria (P < 0.001), reduced creatinine clearance (P < 0.001), and belonging to the 4th HbA1c quartile (P = 0.06). In Kaplan-Meier analysis, mortality was linearly associated with poor glycemia, whereas RRT incidence appeared to rise at a HbA1c threshold of approximately 8.5%.

Conclusion/Interpretation: In the Lainz T1DM cohort, 13.0% mortality and 5.6% RRT were directly associated with and more frequently found in poor glycemia, showing that good glycemic control is essential for the longevity and quality of life in T1DM.
Regulation of epithelial wound closure and intercellular adhesion by interaction of AF6 with actin cytoskeleton
Authors: Lorger Mihaela , Moelling Karin
Published: August 2006

AF6 is a human multi-domain protein involved in signaling and organization of cell junctions during embryogenesis. Its homologue in rat is called afadin. Three different AF6 transcripts are known, but only isoform 1 (AF6i1) has been characterized as protein. We focused on the AF6 isoform 3 (AF6i3), which differs from the AF6i1 by an additional C-terminal F-actin-binding site. Knockdown of AF6i3 in epithelial cells, which express only this isoform, resulted in impaired E-cadherin-dependent intercellular adhesion due to concomitantly reduced association of E-cadherin with F-actin and p120-catenin. Impaired intercellular adhesion also accelerated wound closure due to increased directionality of cell migration and delayed de novo formation of cell junctions. In contrast to AF6i3, the AF6i1 displayed a reduced association with the actin cytoskeleton and did not stabilize intercellular adhesion. Therefore, we propose that the AF6i3 protein stabilizes E-cadherin-dependent adhesion during dynamic processes, such as wound closure and formation of cell junctions, by linking the E-cadherin-catenin complex to the actin cytoskeleton via its F-actin-binding site.
Inositol 1,4,5-trisphosphate supports the arrhythmogenic action of endothelin-1 on ventricular cardiac myocytes
Authors: Proven Andrew , Roderick H. Llewelyn , Conway Stuart J. , Berridge Michael J. , Horton Jeffrey K. , Capper Stephen J. , Bootman Martin D.
Published: August 2006

Although ventricular cardiomyocytes express inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] receptors, it is unclear how these Ca2+ channels contribute to the effects of Gq-coupled agonists. Endothelin-1 augmented the amplitude of pacing-evoked Ca2+ signals (positive inotropy), and caused an increasing frequency of spontaneous diastolic Ca2+-release transients. Both effects of endothelin-1 were blocked by an antagonist of phospholipase C, suggesting that Ins(1,4,5)P3 and/or diacylglycerol production was necessary. The endothelin-1-mediated spontaneous Ca2+ transients were abolished by application of 2-aminoethoxydiphenyl borate (2-APB), an antagonist of Ins(1,4,5)P3 receptors. Incubation of electrically-paced ventricular myocytes with a membrane-permeant Ins(1,4,5)P3 ester provoked the occurrence of spontaneous diastolic Ca2+ transients with the same characteristics and sensitivity to 2-APB as the events stimulated by endothelin-1. In addition to evoking spontaneous Ca2+ transients, stimulation of ventricular myocytes with the Ins(1,4,5)P3 ester caused a positive inotropic effect. The effects of endothelin-1 were compared with two other stimuli, isoproterenol and digoxin, which are known to induce inotropy and spontaneous Ca2+ transients by overloading intracellular Ca2+ stores. The events evoked by isoproterenol and digoxin were dissimilar from those triggered by endothelin-1 in several ways. We propose that Ins(1,4,5)P3 receptors support the development of both inotropy and spontaneous pro-arrhythmic Ca2+ signals in ventricular myocytes stimulated with a Gq-coupled agonist.
Conserved and specific functions of axoneme components in trypanosome motility
Authors: Branche Carole , Kohl Linda , Toutirais Géraldine , Buisson Johanna , Cosson Jacky , Bastin Philippe
Published: August 2006

The Trypanosoma brucei flagellum is unusual as it is attached along the cell body and contains, in addition to an apparently conventional axoneme, a structure called the paraflagellar rod, which is essential for cell motility. Here, we investigated flagellum behaviour in normal and mutant trypanosome cell lines where expression of genes encoding various axoneme proteins (PF16, PF20, DNAI1, LC2) had been silenced by RNAi. First, we show that the propulsive wave (normally used for forward motility) is abolished in the absence of outer dynein arms, whereas the reverse wave (normally used for changing direction) still occurs. Second, in contrast to Chlamydomonas - but like metazoa, the central pair adopts a fixed orientation during flagellum beating. This orientation becomes highly variable in central-pair- and outer-dynein-arm-mutants. Third, the paraflagellar rod contributes to motility by facilitating three-dimensional wave propagation and controlling cell shape. Fourth, motility is required to complete the last stage of cell division in both insect and bloodstream stages of the parasite. Finally, our study also reveals the conservation of molecular components of the trypanosome flagellum. Coupled to the ease of reverse genetics, it raises the interest of trypanosomes as model organisms to study cilia and flagella.
Cell and fibronectin dynamics during branching morphogenesis
Authors: Larsen Melinda , Wei Cindy , Yamada Kenneth M.
Published: August 2006

Branching morphogenesis is a dynamic developmental process shared by many organs, but the mechanisms that reorganize cells during branching morphogenesis are not well understood. We hypothesized that extensive cell rearrangements are involved, and investigated cell migration using two-color confocal time-lapse microscopy to image cell and extracellular-matrix dynamics in developing salivary glands. We labeled submandibular salivary gland (SMG) epithelial cells with green fluorescent protein and matrix with fluorescent fibronectin. Surprisingly, we observed substantial, rapid and relatively random migration of individual epithelial cells during branching morphogenesis. We predicted that cell migration would decrease after formation of acini and, indeed, found that rapid cell movements do not occur in SMG from newborn mice. However, in embryonic SMG epithelial cells, we observed an absence of choreographed cell migration, indicating that patterned cell migration alone cannot explain the highly ordered process of branching morphogenesis. We therefore hypothesized a role for directional fibronection assembly in branching. Washout and pulse-chase experiments revealed that older fibronectin accumulates at the base of the clefts and translocates inwards as a wedge, with newer fibronectin assembling behind it. These findings identify a new mechanism for branching morphogenesis involving directional fibronectin translocation superimposed on individual cell dynamics.
centrosomin's beautiful sister (cbs)encodes a GRIP-domain protein that marks Golgi inheritance and functions in the centrosome cycle inDrosophila
Authors: Eisman Robert C. , Stewart Natasha , Miller David , Kaufman Thomas C.
Published: August 2006

The mechanism of inheritance of the Golgi complex is an important problem in cell biology. In this study, we examine the localization and function of a Golgi protein encoded by centrosomin's beautiful sister (cbs) during cleavage in Drosophila melanogaster. Cbs contains a GRIP domain that is 57% identical to vertebrate Golgin-97. Cbs undergoes a dramatic relocalization during mitosis from the cytoplasm to an association with chromosomes from late prometaphase to early telophase, by a transport mechanism that requires the GRIP domain and Arl1, the product of the Arf72A locus. Additionally, Cbs remains independent of the endoplasmic reticulum throughout cleavage. The use of RNAi, Arf72A mutant analysis and ectopic expression of the GRIP domain, shows that cycling of Cbs during mitosis is required for the centrosome cycle. The effects on the centrosome cycle depend on Cbs concentration and Cbs transport from the cytoplasm to DNA. When Cbs levels are reduced centrosomes fail to mature, and when Cbs transport is impeded by ectopic expression of the GRIP domain, centrosomes undergo hypertrophy. We propose that, Cbs is a trans-Golgi protein that links Golgi inheritance to the cell cycle and the Drosophila Golgi is more vertebrate-like than previously recognized.
A Structure-Activity Relationship in the Binding of Multicharged Anionic Azo and Pyrene Dyes to Serum Albumin
Authors: Murakami Kiyofumi , Akamatsu Miki , Sano Takayuki
Published: August 2006

The binding of 11 azo and pyrene dyes (which have 1 to 4 sulfonato groups) to bovine serum albumin at pH = 7.0 and 25 °C has been studied by spectrophotometry, equilibrium dialysis, and/or ultrafiltration method. Binding parameters were determined assuming one or two classes of independent binding sites. By combining with data reported before, we examined the effects of hydrophobicity and net charge number of ligands on the binding parameters for a total of 19 dyes. The ratio of the binding ability to the primary sites to the total binding ability, a measure of binding specificity, was found to increase with an increase in the anionic charge number of ligands. The values of binding constant for nonspecific binding of the monoanionic dyes and for the primary binding of the multicharged dyes were found to have a strong correlation to both the hydrophobicity and the anionic charge number of ligands. A multiple regression analysis has derived the equation:

where K is a binding constant, P is the partition coefficient in 1-octanol/water system, and m and αi are respectively the number of anionic groups and the degree of dissociation of the i-th group. From this equation, the contribution of electrostatic interactions due to a unit net charge on ligands to the standard free energy change of binding was estimated to be −11.4 kJ mol−1. The role of electrostatic interactions has been discussed in detail.
Decoupling Surface Analysis of Cl+Cl2 Reaction Embedded in Ar52 Cluster
Authors: Someda Kiyohiko , Nakamura Hiroki
Published: August 2006

A model triatomic reaction Cl + Cl2 → Cl2 + Cl embedded in an Ar52 van der Waals cluster is analyzed classical mechanically by a novel theoretical method called “decoupling surface analysis”. This method generates new reactive and vibrational variables in which the kinetic coupling as well as the potential coupling are minimized. An analysis of local frequencies of the vibrational variables along the reaction coordinate clarifies how the motions of ambient Ar atoms are coupled with the central Cl3 system. When the local frequencies are plotted as a function of the reaction coordinate, avoided crossings among these curves are observed. Mixing of Cl motion and Ar motion is clearly detected by these avoided crossings. The vibrational mode having a character of the symmetric stretch of Cl3 shows exclusively strong coupling with the reactive motion. This mode, however, very weakly couples with the ambient Ar motion. On the other hand, the bending and translation of Cl3 are strongly mixed with the motions of ambient Ar atoms and produce unstable modes, which play the most significant role in energy exchange between the central reaction system and the ambient Ar atoms.
Electrochemical Characteristics of Polythiophene Film Electrodes in Acetonitrile Solution
Authors: Komura Teruhisa , Kitani Naoki , Takahashi Koshin
Published: August 2006

The effect of electrode potential and film thickness on the kinetic parameters of the oxidation process of polythiophene (PT) was investigated by an a.c. impedance method and conductivity measurements. The conductivity of a PT film increased with its oxidation and reached a limiting value at higher potentials than 0.8 V despite a rise in oxidation state of PT. The oxidation of the PT film lowered the activation energy of electric conduction, which suggested the broadening of a polaron band. An increase in the oxidized form of thiophene unit brings about the decrease in charge transfer resistance at the polymer electrode in the lower potential range than the half-wave potential of PT. Both the redox capacitance of the polymer and d.c. resistance associated with the diffusion of a charge carrier indicated the dependence on the potential and film thickness which was expected from a finite diffusion model. A large capacitance of the order of 1—30 mF cm−2 in the oxidized state is explained in terms of the charge saturation effect due to the finite thickness and porous nature of the polymer film.
Mechanism of Dye-Sensitized Reaction of Excited Singlet of Anthracene Derivatives through Triplet Energy Transfer and the Annihilation Processes
Authors: Usui Yoshiharu , Tanaka Naomi , Yoshida Masao , Asai Yasufumi , Hirayama Masatoshi
Published: August 2006

Absorption of visible light by acridine orange (AOH+) brought about the photoaddition of CCl4 to the excited singlet of anthracene derivatives, (1A*), which occurred by the direct excitation with UV light. From the dependence of the quantum yields on the concentrations of CCl4 and A and on the light intensity in ethanol solution, a mechanism involving the triplet energy transfer from 3AOH+ to A and the annihilation of 3A to form 1A* is proposed.
Crystal Structure and Physical Properties of (BDT-TTP)2ClO4
Authors: Mori Takehiko , Misaki Yohji , Fujiwara Hideki , Yamabe Tokio
Published: August 2006

The ClO4, BF4, and ReO4 salts of BDT-TTP, 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene, are isostructural, having uniform columns of the donor molecules. These salts are essentially metallic down to low temperatures, though the resistivity increases to some extent below 200 K. The thermoelectric power and ESR show simple metal-like behavior down to low temperatures.
Oxidation of Iron(II) during Solvent Extraction with Benzoyltrifluoroacetone into Carbon Tetrachloride in the Absence and Presence of Tetrabutylammonium Ion or Trioctylphosphine Oxide
Authors: Sekine Tatsuya , Nguyen Thi Kim Dung
Published: August 2006

The solvent extraction of iron(II) in aqueous 0.1 mol dm−3 sodium nitrate solutions containing ascorbic acid with benzoyltrifluoroacetone (Hbfa) into carbon tetrachloride was studied in the absence and presence of tetrabutylammonium ion (tba+) or trioctylphosphine oxide (TOPO). By the addition of tba+, the tba+Fe(bfa)3− species, and by the addition of TOPO, the Fe(bfa)2TOPOn (n = 1 or 2) species were extracted in addition to the Fe(bfa)2 species and the extraction was greatly enhanced. The iron(II) in the benzoyltrifluoroacetonate complex extracted in the organic phase was oxidized rather quickly and the rate of this oxidation was also studied. An addition of tba+ or TOPO to the system slowed down the oxidation reaction, and the reason for the effects of tba+ and TOPO on the rate of oxidation is discussed.
Synthesis and Characterization of Ta2O5–SiO2 Mixed Oxides
Authors: Guiu Garbine , Grange Paul
Published: August 2006

Mixed oxides, especially silica containing multicomponent oxides, have recently found many applications in the production of glasses, ceramics and catalysts. This paper reports for the first time the synthesis of SiO2–Ta2O5 mixed oxide by the sol–gel method. The advantage of the sol–gel method is that a relatively large concentration of tantalum can be incorporated in the mixed oxide structure. Physicochemical characterization shows that tantalum atoms are incorporated into the silica matrix producing Si–O–Ta bonds.
Studies on the Interaction between Iron(III) and Glycerol or Related Polyols over a Wide pH Range
Authors: Mori Yasuyoshi , Yokoi Hiroshi
Published: August 2006

The interaction between iron(III) and glycerol or related polyols was studied in some detail over a pH range of 1 to 13 mainly by spectrophotometric and NMR measurements. At acidic pH, there appeared a new absorption band at 350 nm in the difference spectra of iron(III) before and after the addition of glycerol, showing that iron(III) and glycerol form a 1 : 1 complex. Although the 13C NMR relaxation rates for all of the carbon atoms of glycerol and 1,3-propanediol were markedly affected by the addition of iron(III), the rate for C-2 of 1,4-butanediol remained unchanged. These facts indicate that either 1,2- or 1,3-diol, as didentate ligand, coordinates to a hydrolyzed iron(III) ion at acidic pH. In all of the present systems of iron(III) and polyols, iron(III) hydroxide-like precipitates resulted at around neutral pH. The polyols were removed in some quantities from solutions by adsorption on the precipitates; the removability depended on their molecular structures. In these polyols, only glycerol, which has three neighboring OH groups, formed soluble complexes at pH > 9 if R > 20. Accordingly, three neighboring OH groups seemed to be essential in the formation of soluble complexes at alkaline pH. In conclusion, the interaction between iron(III) and polyols are severely dependent upon the molecular structures of the polyols.
Stability on Drying of Cyclodextrin Precipitates of Volatile Nonelectrolytes
Authors: Sanemasa Isao , Wu Yue , Koide Yuuki , Fujii Toshie , Takahashi Hiroko , Deguchi Toshio
Published: August 2006

Cyclodextrins (CyD’s) were precipitated in aqueous medium at 25 °C as inclusion complexes with twenty-two volatile nonelectrolytes (guests). The guest/CyD molar ratios of precipitates were measured immediately after preparation and after drying. Drying the precipitates for five hours at 50 °C under reduced pressure using a water-suction pump gave the same guest/CyD molar ratios as those obtained by drying in a desiccator over diphosphorus pentaoxide and stored there for two weeks. An iodine–α-CyD complex is quite stable on drying and, next to it are 1,2,3-trimethylbenzene–α-CyD and 1,2,4-trimethylbenzene–β-CyD complexes; other guest–CyD complexes are more or less unstable. The stability was found to be roughly correlated to the van der Waals volume of guest molecule(s) resident maximally in the CyD cavity.
MM2 Molecular Mechanics Studies of Periplanone B and Nitroxides. Empirical Methods to Evaluate the Stretching (ks) and Bending (kb) Force Constants of the MM2 Force Field
Authors: Sakakibara Kazuhisa , Kawamura Hidetaka , Nagata Takashi , Ren Jingzhu , Hirota Minoru , Shimazaki Kazuko , Chuman Tastuji
Published: August 2006

The MM2 force field has been extended so as to deal with periplanone B and nitroxides by using empirical relationships which enable us to derive the MM2 stretching (ks) and bending force (kb) constants systematically. The stretching force constants (ks) could be correlated well with the bond order (N) and equilibrium bond length (r0) by the equation ks = a(N/r03) + b. Three different sets of parameters (a, b) were assigned to the bonds, which were classified according to the atoms forming the bonds. The bending force constants (kb) could be estimated by the equation , where ks1 and ks2 are the stretching force constants of the bonds which comprise the bond angle. The angle types were classified into six groups in the MM2 force field. After assigning ks and kb, the torsional parameters (V1, V2, V3) were determined so as to reproduce the ab initio conformational energies and structural data of the model compounds for the periplanone B and nitroxides. The MM2 calculations using the parameters thus obtained reproduced the experimental structures and conformational energies of periplanone B and the spin adducts of nitrone spin traps correctly.
Preparation of New Nitrogen-Bridged Heterocycles. 37. Synthesis and Rearrangement of Full-Conjugated Oxepino[2,3-b]indolizine Derivatives
Authors: Kakehi Akikazu , Ito Suketaka , Muranaka Hideyuki
Published: August 2006

The title compounds were first synthesized in considerably good yields by acid-catalyzed dehydration of the corresponding ethyl 2-arylcarbonyl-3-hydroxy-3-phenyl-2,3-dihydrooxepino[2,3-b]indolizin-4-carboxylate derivatives with methanesulfonic acid in boiling chloroform. Although these full-conjugated oxepino[2,3-b]indolizines with a nonaromatic 16π electron system were stable at room temperature, upon heating them in boiling ethanol, they were smoothly rearranged to ethyl 2-arylcarbonyl-1-oxo-2-phenyl-1,2-dihydropyrido[1,2-a]indole-3-carboxylates in good yields. The structures of these oxepino[2,3-b]indolizines and the rearranged pyrido[1,2-a]indol-1(2H)-ones were distinctly determined by physical and spectral means, including X-ray analyses.
Claisen Rearrangement of 4-Allyloxytropones and Cerium(IV) Ammonium Nitrate-Oxidation of 4-Hydroxytropones
Authors: Nakamura Arisa , Kubo Kanji , Ikeda Yukari , Mori Akira , Takeshita Hitoshi
Published: August 2006

Heating 4-allyloxytropones gave Claisen rearrangement products together with oxidation products such as C–C coupling dimers. The products were sensitive to oxygen. Some of the dimeric products were obtained from the cerium(IV) ammonium nitrate-oxidation of 4-hydroxytropones.
Formation of Inclusion Complexes of Oligoethylene and Its Derivatives with α-Cyclodextrin
Authors: Li Jun , Harada Akira , Kamachi Mikiharu
Published: August 2006

Oligoethylene (OE) was found to form inclusion complexes with α-cyclodextrin (α-CD) not only from aqueous solutions of α-CD but also from DMF solutions of α-CD to give stoichiometric compounds in a crystalline state in high yields. The yields depend on the oligomeric degree (n) of OE when DMF was used as solvent. OE of n less than 6 did not form complexes with α-CD in DMF solution. The complexes were characterized by IR, 1H NMR, 13C NMR, and 13C CP/MAS and PST/MAS NMR spectra, X-ray (powder), and elemental analysis. The continuous variation plots for the complex formation and the 1H NMR spectra of the complexes show that the stoichiometry of the crystalline complexes is 3 : 1 (ethylene unit–α-CD). The X-ray powder pattern of α-CD–OE complexes and the solid state 13C CP/MAS, PST/MAS NMR spectra suggest that the OE chain is included in the channel formed by α-CD molecules and that the OE backbone in the complexes is more flexible than that in uncomplexed state (OE crystal) due to being included in the cavities of α-CD. Derivatives of OE(6) with small end groups, such as hydroxyl, carboxyl and amino groups, formed crystalline complexes with α-CD, but OE(6) carrying large end groups, such as 2,4-dinitrophenyl and 2,4,6-trinitrophenyl groups, did not form complexes with α-CD. However, it is found that derivatives of OE(6) with charged end groups, such as ammonio or carboxylato groups, do not form crystalline complexes with α-CD, but can form 1 : 1 (guest molecule–α-CD) complexes which are in equilibrium in aqueous solution. The complexation of diammoniohexaethylene cation (DAHE cation) with α-CD in aqueous solution was discussed by using 1H NMR and 2D NOESY NMR spectra.
Effect of α-Cyclodextrin on the Hydration of Aliphatic Aldehydes in Water
Authors: Wang An Sheng , Matsui Yoshihisa
Published: August 2006

The 1H NMR spectrometry of aliphatic aldehydes in D2O showed that the addition of α-cyclodextrin (α-CD) causes a marked change in the hydration equilibrium of ethanal in favor of the unhydrated aldehyde. The inhibitory effect of α-CD on hydration was smaller in propanal than in ethanal and negligible in butanal, pentanal, and hexanal.
Effect of Catalyst Preparation on the Oxidative Coupling of Methane over SrO–La2O3
Authors: Okabe Kiyomi , Sayama Kazuhiro , Kusama Hitoshi , Arakawa Hironori
Published: August 2006

The surface Sr/La ratio of SrO–La2O3 catalysts was almost unchanged within the bulk ratio of Sr/La = 0.02—0.2 when calcined at 1173 K. The reaction results showed that the selectivity to C2+ hydrocarbons depends on the catalyst preparation, which affects the surface morphology and the basicity of the catalysts.
Formation of Stable Gel Colors of Calcium Alginate
Authors: Takahashi Yasuko
Published: August 2006

By a newly developed gel-preparation method using binary aqueous mixed solvents, such as a methanol–water or an ethanol–water mixture, before gelation as a sol solvent and after gelation as a gel environmental solvent, stable gel colors and xerogel colors of calcium alginate (Ca alg.) including photosensitive chlorophyll a (chl.a) were obtained. Ca alg. gel containing leucomalachite green (leuco-M) was made by using the same mixed solvents; after gelation by immersion in mixed solvents or in an acidic solution of various pH values, color development was investigated under ultraviolet irradiation (365 nm). From gel rupture stress measurements, absorption spectral measurements, and an X-ray diffraction study, etc., it was found that such gel-color stability mainly depends on the conformational stability of the host gel.
A Modification of Block–Walker’s Reaction Field for a Non-Ideal Dipole
Authors: Abe Takehiro
Published: August 2006

Block-Walker’s reaction field derived from considering a distance-dependent relative permittivity for a point dipole in the center of a spherical cavity is modified for a non-ideal dipole directed along the radius vector. The reaction field energies of the non-ideal dipole for two special cases are compared with those of the point dipole in the center of the cavity. Thus, the validity of approximation of Block–Walker’s reaction field is investigated.
The Crystal Structure of cis-β-Λ-Carbonato(S,S-triethylenetetramine)cobalt(III) Perchlorate: Spontaneous Resolution and Determination of Absolute Configuration
Authors: Masuda Hideki , Masuda Chie , Jitsukawa Koichiro , Einaga Hisahiko
Published: August 2006

The single crystal of cis-β-Λ-S,S-[Co(CO3)(trien)](ClO4)·H2O (trien = triethylenetetramine) has spontaneously resolved from the aqueous solution of cis-α-[CoCl(NH3)(trien)](ClO4)2 containing hydrogencarbonate anion, whose crystal structure has been determined by X-ray diffraction method. The complex crystallizes in the monoclinic space group P21 with a = 7.410(1), b = 12.354(3), c = 8.676(1) Å, β = 108.88(1)°, and Z = 2. The final R and Rw values for the 3056 observed reflections with Io > 3σ(Io) are 0.045 and 0.055, respectively. The tetradentate ligand, trien, is linked to the cobalt atom in cis-β-configuration, and the carbonato anion is coordinated to the metal atom as a didentate ligand. The Co–N bond lengths are 1.904(6), 1.928(4), 1.941(4), and 1.955(5) Å, and the two Co–O bond lengths are both 1.909(4). The absolute configuration of the complex cation can be designated as Λ(λλδ) and those about two secondary nitrogen atoms are both S.
Copper(I) Iodide Coordination Polymer with Tetrakis(ethylthio)tetrathiafulvalene (TTC2-TTF) and the Iodine-Doped Compound
Authors: Gan Xinmin , Munakata Megumu , Kuroda-Sowa Takayoshi , Maekawa Masahiko
Published: August 2006

The title complex was synthesized by the reaction of copper(I) iodide and tetrakis(ethylthio)tetrathiafulvalene (TTC2-TTF) in acetonitrile under argon atmosphere. The new compound, [(CuI)2TTC2-TTF], crystallizes in the monoclinic system, space group P21/m with unit-cell dimensions a = 9.843(2), b = 12.946(2), c = 10.079(1) Å, β = 99.91(1)°, V = 1265.2(4) Å3, and Z = 2. It is a neutral 2 : 1 (metal/ligand) complex in which each metal ion is tetrahedrally coordinated by two bridging iodide ions and two sulfur atoms from TTC2-TTF to form coordination polymeric chains. The average Cu–I and Cu–S bond lengths are 2.601 and 2.369 Å, respectively. The complex was doped with iodine to afford [(CuI)2TTC2-TTF]I1.5 which exhibits a conductivity of 2 × 10−3 S cm−1 at 25 °C for a compacted pellet.
Silver(I) Ion-Mediated Desulfurization-Condensation of Thiocarbonyl Compounds with Several Nucleophiles
Authors: Shibuya Isao , Taguchi Yoichi , Tsuchiya Tohru , Oishi Akihiro , Katoh Eisaku
Published: August 2006

The desulfurization-condensation reaction was investigated in the presence of silver(I) salt for several kinds of thiocarbonyl compounds with nucleophiles. Such thiocarbonyl compounds as 4,4′-bis(dimethylamino)thiobenzophenone, ethylene trithiocarbonate, and N-(thiobenzoyl)morpholine react with malononitrile or other active methylene compounds in the presence of silver trifluoroacetate to afford the corresponding olefinic compounds together with silver sulfide. This reaction of thiocarbonyl compounds with some other nucleophiles, such as aniline derivatives and ethylene glycol, has also afforded imines and 1,3-dioxolane derivatives.
Synthesis of Rigid Porphyrin-Quinone Compounds for Studying Mutual Orientation Effects on Electron Transfer and Their Photophysical Properties
Authors: Tsue Hirohito , Nakashima Shuichi , Goto Yasushi , Tatemitsu Hitoshi , Misumi Soichi , Abraham Raymond J , Asahi Tsuyoshi , Tanaka Yoshinori , Okada Tadashi , Mataga Noboru , Sakata Yoshiteru
Published: August 2006

A series of covalently linked porphyrin-quinone molecules in which a porphyrin ring is connected at two fixed distances with two different kinds of rigid spacers to benzoquinone were synthesized. The spacer is either spiro[4.4]nonane or trans-decalin. These compounds were designed to have a fixed orientation of different kinds with the same redox pair, the same separation distance, and the same number of intervening bonds. The forward electron-transfer rates were studied by fluorescence–lifetime measurements. Large differences in the rates were found in each pair, and the rates for those compounds having a spiro spacer were larger than those with a trans-decalin spacer. These differences were attributed to a difference in the molecular geometry of the spacer groups in each pair.
Syntheses of Rotational Isomers of Substituted 9-t-Butyltriptycenes That Carry an Oxygen Substituent in t-Butyl Group and Outstanding Steric Effects Observed in the Synthesis of an Intermediate
Authors: Oki Michinori , Miyasaka Tsutomu , Katafuchi Osamu , Ishizuka Takayuki , Toyota Shinji
Published: August 2006

The title rotational isomers were synthesized. Reduction of methyl 2-(9-anthryl)-2-methylpropanoate caused difficulty due to severe steric effects. Thus the compound was converted to the free acid by treating it with a lithium thiolate and the resulted acid was reduced to the corresponding alcohol with borane. The alcohol was protected as either an acetate or a silyl ether and was subjected to the reaction with a benzyne. The resulted rotamers of triptycenes were separated by chromatography. Rotamers that carry an acetoxy, a hydroxy, or a t-butoxy substituent were prepared.
A Novel Synthesis of C/D-Rings Component of Phytochromobilin Dimethyl Ester
Authors: Kohori Kazuhiro , Hashimoto Masami , Kinoshita Hideki , Inomata Katsuhiko
Published: August 2006

C/D-Rings component of phytochromobilin dimethyl ester was readily synthesized by employing our recent new preparative method for 3,4-disubstituted 1,5-dihydro-2H-pyrrol-2-ones and their coupling with a 2-formylpyrrole. A convenient method for the preparation of a substituted pyrrole common to B- and C-rings was also described.
Surface Acidity-Cracking Activity Correlation in Chromium Pillared Clays
Authors: Vijayakumar S , Vijaya C , Rengaraj K , Sivasankar B
Published: August 2006

Chromium pillared montmorillonite and vermiculite catalysts have been prepared by intercalation with hydrolyzed metal ion solution. Pillaring solutions with different chromium concentrations were prepared by varying the base to chromium ratio. The catalysts were characterized by nitrogen adsorption, XRD, and IR studies. The nature of the acid sites was characterized by means of IR spectra data on pyridine adsorbed chromium pillared catalysts. The acidity of the samples was determined by butylamine titration. DSC has been used in the present study to probe the nature of the surface acidity, its heterogeneity, acid strength, and density of acidic sites. Cumene cracking was carried out as a test reaction of Brønsted acidity. Both the density and strength of Brønsted acid sites were found to influence the cracking activity.