bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phase I Study of Depsipeptide in Pediatric Patients With Refractory Solid Tumors: A Children's Oncology Group Report
Authors: Fouladi Maryam , Furman Wayne L. , Chin Thomas , Freeman Burgess B. , Dudkin Lorina , Stewart Clinton F. , Krailo Mark D. , Speights Roseanne , Ingle Ashish M. , Houghton Peter J. , Wright John , Adamson Peter C. , Blaney Susan M. 
Published: July 2006

Purpose To determine the maximum-tolerated dose (MTD), dose-limiting toxicities (DLT), pharmacokinetic profile, and pharmacodynamics of the histone deacetylase inhibitor, depsipeptide, in children with refractory or recurrent solid tumors. Patients and Methods Depsipeptide was administered as a 4-hour infusion weekly for 3 consecutive weeks every 28 days at dose levels of 10 mg/m2, 13 mg/m2, 17 mg/m2, and 22 mg/m2. Pharmacokinetics and histone acetylation studies were performed in the first course. The levels of H3 histone and acetyl-H3 histone were evaluated in peripheral blood mononuclear cells (PBMC) using immunofluorescence techniques. Results There were 24 patients, and 18 who were assessable were enrolled. DLTs included reversible, asymptomatic T-wave inversions, without any associated changes in troponin levels or evidence of ventricular dysfunction, in the inferior leads in two patients at 22 mg/m2 and in the lateral leads in one patient at 13 mg/m2 (n = 1), and transient asymptomatic sick sinus syndrome and hypocalcemia in one patient at 17 mg/m2. At the MTD (17 mg/m2), the median depsipeptide clearance was 6.8 L/h/m2 with an area under the plasma depsipeptide concentration-time curve from 0 to infinity of 2,414 ng/mL/h, similar to adults. Accumulation of acetylated H3 histones was seen in all patients in a dose independent manner, with maximal accumulation at a median of 4 hours, (range, 0 hours to 20 hours) after the end of the infusion. No objective tumor responses were observed. Conclusion Depsipeptide is well tolerated in children with recurrent or refractory solid tumors when administered weekly for 3 consecutive weeks every 28 days and inhibits histone deacetylase activity in PBMC in a dose-independent manner. The recommended phase II dose in children with solid tumors is 17 mg/m2.
Increasing Negative Lymph Node Count Is Independently Associated With Improved Long-Term Survival in Stage IIIB and IIIC Colon Cancer
Authors: Johnson Paul M. , Porter Geoff A. , Ricciardi Rocco , Baxter Nancy N. 
Published: July 2006

Purpose The purpose of this study was to examine the impact of the number of negative lymph nodes on survival in patients with stage III colon cancer. Patients and Methods Patients who underwent surgery for stage III colon cancer between January 1988 and December 1997 were identified from the Surveillance, Epidemiology and End Results cancer registry. The number of negative and positive nodes was determined for 20,702 eligible patients. Disease-specific survival was examined by substage according to the number of negative nodes identified. A proportional hazards model was constructed to determine the effect of the number of negative nodes on survival. Results For stage IIIB and IIIC patients, there was a significant decrease in disease-specific mortality as the number of negative nodes increased; cumulative 5-year cancer mortality was 27% in stage IIIB patients with 13 or more negative nodes identified versus 45% in those with three or fewer negative lymph nodes evaluated (P < .0001). In patients with stage IIIC cancer, those with 13 or more negative nodes had a 5-year mortality of 42% versus 65% in those with three or fewer negative lymph nodes evaluated (P < .0001). There was no association between the number of negative nodes identified and disease-specific survival for patients with stage IIIA disease. After controlling for the number of positive nodes, a higher number of negative nodes was found to be independently associated with improved disease-specific survival. Conclusion The number of negative nodes is an important independent prognostic factor for patients with stage IIIB and IIIC colon cancer.
Charge-Transfer Molecular Complexes of Thianes with σ and π Electron Acceptors
Authors: Hamed Maher M A , Mohamed Mona B , Mahmoud Mohamed R 
Published: July 2006

Abstract
Charge-transfer complexes of cyclic thioethers with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone; tetracyanoethylene; chloranil as π-acceptors and with iodine as a σ-acceptor, have been investigated. The spectral characteristics and stability of the formed CT complexes were examined, and are discussed in terms of the donor molecular structure, the nature of the electron acceptor and the solvent polarity. It is deduced that the formed CT complexes are mainly of the weak n–π or n–σ type, where the ground-state wave function is described primarily in terms of the nonbonding structure (D–A). The ionization potentials of the donors were calculated based on the CT energies of their CT complexes. Moreover, solid 1 : 1 CT complexes were synthesized and characterized.
Oxidation Potentials and Absorption Spectra of Phenothiazine Derivatives I. Benzophenothiazines and Triphenodithiazine
Authors: Urasaki Naoyuki , Yoshida Sadamu , Ogawa Takashi , Kozawa Kozo , Uchida Tokiko 
Published: July 2006

Abstract
The homogeneous electrochemical oxidations of four phenothiazine derivatives, three isomers of benzophenothiazine and triphenodithiazine, were studied in acetonitrile solution together with phenothiazine itself. Their first and second redox potentials were determined by means of cyclic voltammetry. In all the materials examined, reversible one-electron oxidations were characterized. The electrogenerated cation radicals, except for triphenodithiazine, underwent a second one-electron oxidation and, after a subsequent chemical transformation, formed the corresponding benzophenothiazinium cations. For triphenodithiazine, only the first oxidation potential was observable under our experimental conditions. The electronic states of both the intermediates and the final products of electrolytic oxidation were identified by their electronic absorption spectra and electron spin resonance absorption spectra. The values of the first oxidation potential of the benzophenothiazines were proportional to the ionization energies, which were given by molecular orbital calculations.
The Phase Transition in the Gel State of the 1,3 : 2,4-Di-O-benzylidene-d-sorbitol/Ethylene Glycol System
Authors: Yamasaki Seiji , Tsutsumi Hisao 
Published: July 2006

Abstract
In chiral oil gelators, only 1,3 : 2,4-di-O-benzylidene-d-sorbitol (d-DBS) can form gels with alcoholic solvents. The d-DBS concentration dependence of the state in the binary system d-DBS/ethylene glycol, were studied using optical, rheological and spectral measurements. Based on the changes in the transmission and mechanical properties, two phase transition points, which depended upon the d-DBS concentration, were observed at 10 and 30 mM. The low-concentration point was the critical gel concentration. The gel was formed above 10 mM. d-DBS formed spherical domains in the gel between 10—30 mM and made continuous crystals on the entire gel above 30 mM. The aggregated structure of d-DBS in ethylene glycol was studied, utilizing electronic and circular dichroism measurements. According to the gelation, the absorption of the transition moment along the long axis of the benzene ring was red-shifted. The relative orientation changed in 10—30 mM from the hyperchromism and hypochromism of the electronic absorptions, but was fixed above 30 mM. d-DBS exhibited remarkable CD enhancements due to the formation of a gel. The concentration dependence of the molar ellipticities of the CD absorptions was similar to the tendency of the electronic spectra. This indicated that the aggregated structure was changed, depending upon the d-DBS concentration in ethylene glycol; the optical and mechanical properties were related to the aggregated structure which d-DBS formed.
Structure Analysis of Adsorbed Layers Formed from Methanol on Platinum Electrodes with an Electrochemical Quartz Crystal Microbalance
Authors: Shimazu Katsuaki , Kaneda Kyohei , Kita Hideaki 
Published: July 2006

Abstract
The adsorbed species formed from methanol on platinum electrodes have been examined with an electrochemical quartz crystal microbalance (EQCM). The mass of the adsorbed species per surface platinum site was determined from the frequency response of the EQCM, together with number of electrons per Pt site required to oxidize the adsorbed species and coverage from the current response of the EQCM. These values were used to calculate the molar mass of the adsorbed species and the number of adsorption sites. The average composition of the adsorbed species was similar both in 0.1 M HClO4 and 0.01 M NaOH, and was COH2.0—2.4. The composition was independent of the adsorption time and the adsorption potential unless the coverage was below 0.2, where accurate determination of the composition was not possible. The average number of adsorption sites was 3.0 in 0.1 M HClO4 and 2.6 in 0.01M NaOH.
Conductometric Study of Ion Association between Tris(oxalato)chromate(III) and Alkali Metal Ions at Temperatures from 0 to 50 °C
Authors: Yokoyama Haruhiko , Hiramoto Toshiaki , Shinozaki Kazuteru 
Published: July 2006

Abstract
Conductivities for aqueous solutions of alkali metal salts of tris(oxalato)chromate(III) ([Cr(ox)3]3−) were measured at various temperatures from 0 to 50 °C. Ion-association constants (KA) between the complex ion and alkali metal ions increased in the order Li+ &lt;&lt; Na+ &lt; K+ &lt; Rb+ &lt; Cs+ and had minimum values (KA(min)) at characteristic temperatures (tmin) in the observed temperature range except for the lithium ion. The appearance of minima of KA suggested the formation of contact ion pairs besides that of solvent-separated ones. The contact ion-pair formation was considered to be assisted by weak hydration of alkali metal ions and enhanced with decreasing their hydration strength. The lithium ion was presumed to form only solvent-separated ion pairs on the basis of extremely small ion-association constants. Temperature dependence of log KAfor each ion association could be represented by the equation: log KA = p(t − tmin)2 + log KA(min). A common relationship between p and tmin was found out for the ion-association systems of [Cr(ox)3]3−, [Co(NH3)6]3+, and [Co(en)3]3+ (en = ethylenediamine), and p was expressed by an empirical quadratic equation in tmin. The standard enthalpy changes of ion association (ΔHas°) at any temperature for these complex systems could be reproduced within ±0.2 kJ mol−1 by use of these equations with the experimental tmin. Hydration behavior of [Cr(ox)3]3− was also discussed based on limiting molar conductivities and their temperature dependence.
Determination of Trace Copper in Natural Waters after Selective Separation by Flotation
Authors: Ghazy Shaban E , Kabil Mohamed A 
Published: July 2006

Abstract
Microgram amounts of copper(II) in one liter of water are quantitatively separated selectively as copper(II) acetate with oleic acid surfactant at pH range 6.5—7.5. The floated scum is separated, after shaking for few seconds, and measured colorimetrically at 700 nm. Beer’s law is obeyed in the concentration range (0.5—5) × 10−4 mol dm−3, {3.18—31.8 ppm of copper(II)}. Alternatively, the copper in the scum is eluted by nitric acid 0.1 mol dm−3, completed to the suitable volume required for copper atomic absorption measurement at 324.7 nm with 1 ppm detection limit. The different factors affecting the selective flotation of copper(II) have been studied. It has been found that iron(III) seriously depresses the flotation efficiency. The flotation mechanism is discussed. The method of the separation and determination is rapid and applicable to 50 ppb copper(II) concentration level in natural waters.
Dithionite as a New Reductant in the Thiocyanate Method for the Spectrophotometric Determination of Molybdenum
Authors: Dass Rameshwar , Mehta Jaswant Ram 
Published: July 2006

Abstract
Sodium dithionite has been recommended as a new reductant in the thiocyanate method for the spectrophotometric determination of molybdenum. The study is based on prior extraction of molybdenum(VI)–thiocyanate species in ethyl acetate from 0.8 mol dm−3 HCl medium followed by reduction of the complex with dithionite in the organic extract. The orange yellow color so obtained is measured at λmax 468 nm against a reagent blank. The 1 : 5 (Mo : SCN) complex is stable for 1 h in ethyl acetate and obeys Beer’s law over the concentration range 0—2.6 ppm of molybdenum (optimum range for accurate determination is 0.7—2.5 ppm). The molar absorptivity and Sandell sensitivity of the complex are 1.79 × 104 dm3 mol−1 cm−1 and 0.0053 μg Mo cm−2, respectively. The relative standard deviation for nine replicate determinations of 2 μg Mo cm−3 is ±1.1%. Of the tested 40 cations and 24 anions including complexing agents only thiourea interferes in the procedure. The method is sensitive and highly selective. It is applicable to the determination of molybdenum in steels and flue dust samples with satisfactory results.
Hydration to the Poly(oxyethylene) Derivative Complexes of Alkali Metal Ions and Barium Ion in 1,2-Dichloroethane
Authors: Kikuchi Yoichi , Kubota Mitsuru , Suzuki Toshio , Sawada Kiyoshi 
Published: July 2006

Abstract
A series of poly(oxyethylene) derivatives (POE compound) complexes of alkali metal and barium ions were extracted into 1,2-dichloroethane (1,2-DCE) by forming ion-pairs with picrate ion. Water molecules were coextracted into 1,2-DCE with the ion-pairs. The mean number of water molecules bound to the POE compound, XH2O,S, and its complex, XH2O,comp, in water saturated with 1,2-DCE was determined by means of aquametry. The XH2O,S value increases with the increase in the number of the oxyethylene units (EO unit) of the POE compound. The XH2O,comp value decreases in the order Li+ &gt; Na+ &gt; K+ ≈ Rb+ ≈ Cs+ in any POE compound systems, and increases with the number of EO units of the POE compounds for a given metal ion. These results are interpreted by the hypothesis that the water molecules bound to the complex are those hydrated to the central metal ion, and the hydrated metal ion is surrounded by the EO chain with a helical conformation in the complex. The large number of water molecules are coordinating to the lithium ion complexes and bring about a serious distortion in the helical structure of the complexes. Because of the ion-pair formation with two picrate ions, the XH2O,comp values of barium ion complexes are smaller than those of potassium ion complexes.
Kinetics and Mechanisms of a New Type of Catalysis in the Activated Carbon for the Ligand-Substitution Reaction between the Inert Complex [Co(NH3)5Cl]2+ and EDTA in Aqueous Media
Authors: Kimura Masaru , Miyamoto Ikuko 
Published: July 2006

Abstract
The ligand-substitution reaction of the pentaamminechlorocobalt(III) ion, [Co(NH3)5Cl]2+, with ethylenediaminetetraacetate (EDTA) (which denotes all the forms of EDTA, i.e. edta4−, Hedta3−, H2edta2− etc.) occurred efficiently in the presence of the activated carbon (AC) in aqueous media of pH 4.7, where the AC acts as a catalyst of the electron-transfer mediator. The ligand-substitution reaction constitutes a chain reaction composed of an AC and AC+ cycle, where the substitution reaction is initiated by the electron-transfer from AC to the cobalt(III) complex. The formation rate of [Co(edta)]− by the substitution reaction between [Co(NH3)5Cl]2+ and EDTA was of the first-order with respect to concentrations of not only [Co(NH3)5Cl]2+ but also AC, and was of the zero-order with respect to the EDTA concentration. Further, the rate was irrespective of the dissolved oxygen O2. The substitution reaction was always quantitative, i.e. [[Co(NH3)5Cl]2+]decreased = [[Co(edta)]−]formed at any reaction time up to completion of reaction.
Physicochemical Perturbation of α-Linolenic Acid Related to Cell Proliferation
Authors: Fukui Hiroki , Sato Toshinori , Sunamoto Junzo 
Published: July 2006

Abstract
The influence of fatty acids, α-linolenic acid (ALA), and linoleic acid (LA), on lipid membrane dynamics and cell proliferation was investigated. Electron-spin resonance measurements with 2-hexyl-2-(10-methoxycarbonyldecyl)-4,4-dimethyl-3-oxazolidinyloxyl revealed that the penetration of ALA or LA into the liposomal membrane causes an increase in the membrane fluidity and a decrease in the phase-transition temperature of the lipid membrane. When human colon cancer cells (RPMI4788 and BM314) and normal mouse fibroblast (L-cell) were incubated with ALA, the membrane fluidity of the cancer cells significantly increased over that of normal cells. ALA made the cancer cell membrane more fluid than did LA. When ALA was administered at a concentration of 40 μg ml−1, it showed a strong cytotoxicity against the cancer cells, but not to the normal cells. On the other hand, LA (up to 80 μg ml−1) rather promoted growth of the cancer cells. These results seem able to be interpreted as an aspect of the selective cytotoxicities of ALA.
Transformation of Alkyl N-(Vinyloxy)benzimidates to Alkyloxazoles. Mechanism and Extension
Authors: Yokoyama Masataka , Menjo Yasuhiro , Ubukata Makoto , Irie Masakazu , Watanabe Mikari , Togo Hideo 
Published: July 2006

Abstract
Transformation of alkyl N-(vinyloxy)benzimidates to alkyloxazoles proceeds through the intermediates: a charge-separated 1,2-oxazetidine derivative and then 1-hydroxy-2-[[methylthio(phenyl)methylene]imino]maleic acid diester, while their photochemical transformation takes place via a concerted [1,3] sigmatropic shift. As the extension of this reaction, the preparation of the precursor proposed for virginiamycin M2 synthesis and the reaction of N-analogs of alkyl N-(vinyloxy)benzimidates are described.
Solvent Effects on the Solvolysis of Benzyl p-Toluenesulfonates
Authors: Fujio Mizue , Susuki Toshihiro , Goto Mutsuo , Tsuji Yutaka , Yatsugi Ken-ichi , Saeki Yoshihiro , Kim Sung Hong , Tsuno Yuho 
Published: July 2006

Abstract
Solvolysis rates of benzyl p-toluenesulfonate were determined in a wide variety of solvents. The solvent effects were analyzed based on the Winstein–Grunwald equation. The solvent effect on benzyl solvolysis failed to give a single linear correlation with the 2-adamantyl YOTs parameter. The lower response to the solvent polarity and the pattern of dispersion for each binary solvent series can be qualitatively interpreted in terms of nucleophilic solvent assistance. The Winstein–Grunwald analysis gave m = 0.67 and l = 0.36, but with less satisfactory precision. The use of the polarity scale Yneo derived from 2-methyl-2-phenylpropyl solvolysis in place of YOTs gave an improved correlation. A solvent polarity scale Yneo is better applicable to benzyl solvolysis than 2-adamantyl-based YOTs, since the former is compatible with the entire π-delocalization of cationic charge between aryl ring and the reaction center in the transition state.
Stereochemical Control in Microbial Reduction. XXIII. Thermal Treatment of Bakers’ Yeast for Controlling the Stereoselectivity of Reductions
Authors: Kawai Yasushi , Kondo Shin-ichi , Tsujimoto Munekazu , Nakamura Kaoru , Ohno Atsuyoshi 
Published: July 2006

Abstract
The diastereoselectivity in a bakers’ yeast reduction of various alkyl 2-alkyl-3-oxoalkanoates can be controlled by a thermal treatment of the yeast in the presence of methyl vinyl ketone. Pretreated bakers’ yeast gives the corresponding (2R,3S)-hydroxy esters selectively. Two β-keto ester reductases, named l-enzyme-1 and l-enzyme-2, are actual reductants of intact bakers’ yeast reduction. The thermal stability and inhibition constants of the purified enzymes can dictate the stereochemical outcome of pretreated bakers’ yeast reductions.
Aerobic Enantioselective Epoxidation of Unfunctionalized Olefins Catalyzed by Optically Active Salen–Manganese (III) Complexes
Authors: Yamada Tohru , Imagawa Kiyomi , Nagata Takushi , Mukaiyama Teruaki 
Published: July 2006

Abstract
Enantioselective epoxidation of unfunctionalized olefins is achieved by the combined use of molecular oxygen and pivalaldehyde in the presence of a catalytic amount of optically active Mn(III)–salen complexes. N-Alkylimidazoles are effective axial ligands to produce optically active epoxides with high enantioselectivities in the present procedure; that is, 1,2-dihydronaphthalene derivatives and 2,2-dialkyl-2H-chromene derivatives are converted into the corresponding optically active epoxides with 60—92% enantiomeric excess. The key intermediates in the present aerobic epoxidation are also discussed.
Nickel- and Palladium-Catalyzed Aldol-Type Condensation by Enol Esters
Authors: Masuyama Yoshiro , Sakai Tatsuya , Kato Takeshi , Kurusu Yasuhiko 
Published: July 2006

Abstract
PdCl2(PhCN)2–SnCl2, bis(1,5-cyclooctadiene)nickel(0) [Ni(cod)2]/PPh3–Zn, NiBr2(PPh3)2–Zn, or Pd(OAc)2/PPh3–Zn catalytic systems induced aldol-type condensation of isopropenyl acetate with aldehydes to produce 4-substituted (E)-3-buten-2-ones. PdCl2(PhCN)2–SnCl2 was utilized in the aldol-type reaction with any arenecarbaldehyde, bearing either an electron-donating group or an electron-withdrawing group, at 50 °C in acetonitrile. Catalytic systems using zinc, in particular Ni(cod)2/PPh3–Zn, exhibited some high chemoselectivities at 60 °C in dioxane: (1) an aldehyde only reacted in the presence of an internal ester or ketone, (2) olefinic aldehydes only reacted in the presence of saturated aliphatic aldehydes, (3) reactivity in the condensation with substituted benzaldehydes is the inverse of that in usual nucleophilic addition to carbonyl compound, and (4) 2-methoxybenzaldehyde only reacted in the presence of 4-methoxybenzaldehyde. Using PdCl2(PhCN)2–SnCl2, Ni(cod)2/PPh3–Zn, or Pd(OAc)2/PPh3–Zn, cyclic enol ester, namely 5-methyl-2(3H)-furanone also caused aldol-type reaction with carbonyl compounds. The reaction with Ni(cod)2/PPh3–Zn or Pd(OAc)2/PPh3–Zn at 60 °C in dioxane selectively produced 5-substituted 4-acetyl-2(5H)-furanones via dehydrogenation of γ-substituted β-acetyl-γ-butyrolactones.
Oxidative Coupling of Methane over Calcined Coral-Sands: Their Catalytic Property and Comparison with Other Natural Calcium Carbonates
Authors: Yamagata Nobutsugu , Usami Ken , Okazaki Susumu 
Published: July 2006

Abstract
Coral sands calcined at high temperatures of 800 and 1000 °C were found to be an effective catalyst for the oxidative coupling of methane to C2 hydrocarbons, especially with high selectivity. The coral-sand catalyst was almost composed of calcium oxide; however, it also contained small amounts of Na, Sr, Mg ions etc., and had a characteristic structure with many small pores of 2—8 μm in diameter, which were formed during calcination. In order to investigate the role of their components in C2 formation, nine kinds of catalysts were prepared from other natural calcium carbonates, such as turbo shell, short-necked clam shells, and marbles; their catalytic properties were compared with that of the coral-sand catalyst. Consequently, it seemed that the C2 yield was related to the bulk and surface concentrations of sodium in the catalyst, while the maximum-C2 selectivity at 700—800 °C was related to those of strontium. The catalysts of corals and coral sands showed the highest maximum-C2 selectivity as well as the highest strontium-content (about 1.2wt%). It was considered that the strontium ions are well-dispersed in the catalyst and that they enhance the basicity in combination with sodium ions (main active species), leading to the high C2 selectivity.
Contribution of the First-Order Differential of the Potential to the Pressure-Induced Frequency Shift of the Intramolecular Vibrations in Crystal
Authors: Kawano Hiroshi , Maehara Masayoshi , Nibu Yoshinori , Shimada Hiroko , Shimada Ryoichi 
Published: July 2006

Abstract
The pressure-induced frequency shift of the intramolecular vibrations in crystal was calculated using an atom–atom type intermolecular potential. The calculation indicates that the contribution of the first-order differential of the potential to the frequency shift is very small when the potential is well approximated.