bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micelle Formation by Sodium Dodecyl Sulfate in Water–Additive Systems
Authors: Bakshi Mandeep Singh 
Published: June 2006

Abstract
The conductances of sodium dodecyl sulfate (SDS) have been determined in water in the presence of various additives, such as strong nitrogen organic bases (pyridine, 3- and 4-methylpyridines, and 2,6-dimethylpyridine), carboxylic acids (acetic acid, propionic acid, and butyric), and alcohols (methanol (MeOH), 1-butanol (BuOH), 2-methyl-1-propanol, 2-methyl-2-propanol, and 2-methyl-2-butanol) at 25 °C. The conductances of SDS in water in the presence of pyridine and acetic acid at temperatures between 15 and 45 °C have also been measured. From the conductivity data, the critical micellar concentration (cmc), degree of counter-ion association (α), molar conductivities at infinite dilution (Λ0), limiting ionic molar conductivities (), free energy of transfer of the surfactant hydrocarbon chain from medium to the micelle (), free energy of transfer of surface contributions (), and standard enthalpies of micellisation () of SDS have been computed. It has been found that the presence of strong nitrogen organic bases causes strong micelle denaturation, whereas the presence of carboxylic acids and alcohols stabilizes the micelles, with the exception of MeOH and 2-methyl-2-butanol.
The temperature effect on the micellisation of SDS in the presence of pyridine shows that the enthalpy of micellisation becomes less negative along with an increase in temperature. However, the enthalpy of transfer of a hydrocarbon group from an aqueous to a nonpolar environment in the presence of acetic acid is endothermic.
SNP Studies on the Structure of the Short-Lived Radical Pair Generated in the Hydrogen Abstraction Reaction of Anthraquinone from Xanthene
Authors: Shindo Koji , Yamamoto Kaoru , Maeda Kiminori , Azumi Tohru 
Published: June 2006

Abstract
Nuclear-polarization-detected ESR (NP-detected ESR) spectra were measured in the hydrogen abstraction reaction of anthraquinone from xanthene for the purpose of assigning of the radical pair and the geminate product generated from the radical pair. By properly choosing of the nuclear spin of the product, we can obtain the SNP spectra of the two component radicals individually. The sign of the hyperfine coupling constant is discussed and the SNP spectra are assigned as 9-xanthenyl radical and 10-hydroxy-9-anthryloxyl radical from the spectrum simulated by the radical pair theory. Additionally, the features of the cross relaxation process in the intermediate free radical are discussed by examining the DNP components of spectra.
Remarkable Difference between the Kinetic Parameters of a Selective Catalytic Reduction of NO by Ethene on a Copper Ion-Exchanged MFI Zeolite and Al2O3
Authors: Takeda Hiroshi , Iwamoto Masakazu 
Published: June 2006

Abstract
The kinetic parameters have been determined in reaction systems of NO + O2 + C2H4, NO2 + O2 + C2H4, NO + O2, and O2 + C2H4 over a copper ion-exchanged MFI zeolite (Cu-MFI) and Al2O3. The rate equations for the N2 formation in the NO + O2 + C2H4 system on Cu-MFI (553—593 K) and Al2O3 (673—773 K) were expressed by exp (−168000/RT) and exp (−294000/RT), respectively. The significant difference between the equations reveals that the reaction mechanisms or rate-determining steps on Cu-MFI and Al2O3 greatly differ. In addition, the rate equations for N2 and CO2 production were the same on Cu-MFI, while they were different on Al2O3. The reaction mechanism is discussed based on the equations.
Crystal and Molecular Structures of Novel Metal–Carbene Complexes II. Tris{1,1′-(perhydropyrimidine-1,3-diyl-κC2)bis[(ethylimino)methanethiolato-κ2SS′]}tripalladium(II) and {1,1′-(Perhydropyrimidine-1,3-diyl-κC2)bis[(methylimino)methanethiolato-κ2SS′]}(pyridine)palladium(II); Intensity Measurements Using Rapid X-Ray Diffractometers
Authors: Iwasaki Fujiko , Manabe Noriko , Yasui Masanori , Matsumura Noboru , Kamiya Nobuo , Iwasaki Hitoshi 
Published: June 2006

Abstract
The crystal structures of tris{1,1′-(perhydropyrimidine-1,3-diyl-κC2)bis[(ethylimino)methanethiolato-κ2SS′]}tripalladium(II) (5b) and {1,1′-(perhydropyrimidine-1,3-diyl-κC2)bis[(methylimino)methanethiolato-κ2SS′]}(pyridine)palladium(II) (6a) were determined by X-ray structure analyses. When {1,1′-(perhydropyrimidine-1,3-diyl-κC2)bis[(alkylimino)methanethiolato-κ2SS′]}(triphenylphosphine)palladium(II) (3) was treated with 18% HCl aq, a compound (5) was obtained with an elimination of the triphenylphosphine group. A reaction of 5 with pyridine gave a pyridine-coordinating metal–carbene complex (6). Complex 5 has a trimeric structure of the metal–pentalenes consisting of a cyclic (Pd–S)3 framework. In the trimer, each Pd atom is coordinated by three S atoms and one C atom in a square-planar arrangement. Two of the S atoms belong to the same pentalene ring and one belongs to the next pentalene ring. The lengths of interpentalene Pd–S (2.38 Å) are significantly longer than those of intrapentalene Pd–S (2.28 Å). This difference suggests that a trimer is easily cleaved in pyridine to form a pyridine complex 6. The trimeric structure is considered to show an intermediate-like structure of the ligand exchange reaction. Intensity data of 5 were measured by rapid X-ray diffractometers with imaging plates as a two-dimensional detector.
Orbital Phase Control of the Stabilities of π-Conjugated Diradicals
Authors: Iwase Koji , Inagaki Satoshi 
Published: June 2006

Abstract
The concept of orbital phase continuity–discontinuity was applied to π-conjugated diradicals. Cyclic orbital interactions are involved in the spin polarization and delocalization in acyclic π-conjugated diradicals. The relative stabilities of the singlet isomers, those of the triplet isomers, and the spin multiplicities of the ground states were shown to be predicted by the orbital phase properties. The heteroatom effects on the spin preference was shown to be related to the degree of the continuity (discontinuity) of the orbital phase.
Cycloaddition of Carbon Dioxide to 1,2-Epoxypropane Catalyzed by Tetra-t-butylphthalocyaninatoaluminium(III) Hydroxide
Authors: Kasuga Kuninobu , Kato Takao , Kabata Naohiko , Handa Makoto 
Published: June 2006

Abstract
Carbon dioxide was fixed as propane-1,2-diol carbonate (PDC) with 1,2-epoxypropane (EP) catalyzed by Al(OH){pc(t-Bu)4} in the presence of such a quaternary ammonium halide (HAX) as [HO(CH2)2N(CH3)2(C4H9)]X (X = Cl, Br, I). Although the yield was scarcely affected by the structure of HAX, it was dependent on the kind of halide ion. While PDC was formed in chloroform or dichloromethane, the yield decreased extremely in DMSO or pyridine, and PDC was not prepared in methanol. Although halohydrin was formed in a chloroform solution of EP, Al(OH){pc(t-Bu)4}, and HAX, it was not an intermediate.
The formation of a hexa-coordinate complex of Al(OH){pc(t-Bu)4} with HAX and EP was spectroscopically confirmed, and the complex catalyzed the preparation of PDC from carbon dioxide and EP.
Biopolymer–Surfactant Interaction 2: Kinetics of Binding of Cetyltrimethylammonium Bromide with Bovine Serum Albumin
Authors: Maulik Sudeshna , Moulik Satya Priya , Chattoraj Dipti Kumar 
Published: June 2006

Abstract
The results of the kinetics of binding of the surfactant cetyltrimethylammonium bromide (CTAB) with bovine serum albumin (BSA) under varied conditions of CTAB concentration, pH, ionic strength and temperature are presented. The kinetic process has been found to be comprised of either two or three stages; the rate constants of the first, second, and third stages follow the general order of k1 &gt;&gt; k2 &gt; k3. The three-stage kinetic process has been observed at higher CTAB concentrations, higher temperature and in presence of the protein denaturant urea. The activation parameters for this three-stage kinetic process have been determined. Most entropies of activation have been found to be negative (a very few are positive) whereas the activation enthalpies and energies are both positive and negative. The enthalpy and entropy for all the kinetic stages in different environmental conditions have been found to compensate each other, whereas the free energy of activation has remained unaffected. A model for the three-stage kinetic process has been proposed.
Selective Oxyfunctionalization of Ketones Using 1-Oxopiperidinium Salt
Authors: Ren Tan , Liu You-Cheng , Guo Qing-Xiang 
Published: June 2006

Abstract
4-Methoxy-2,2,6,6-tetramethyl-1-oxopiperidinium chloride, made from the corresponding 1-piperidinyloxyl radical and chlorine gas, was used as an oxyfunctionalizing reagent for a number of enolizable ketones. Regioselective α- or γ-oxygenated carbonyl compounds were obtained smoothly at ambient temperature in moderate to good yields. Oxyfunctionalization of (+)-carvone and (−)-carvone proceeded stereoselectively, and provided cis-product (5R, 6S)- and (5S, 6R)-2-cyclohexen-1-ones, respectively. Interestingly, unsymmetrical ketones afforded isomeric α- and α′-oxygenated ketones, while allyl ketones gave the regiospecific γ-oxygenated products with the migration of the double bond in the allylic group.
Selective Synthesis of Sulfoxides and Sulfones by Methyltrioxorhenium-Catalyzed Oxidation of Sulfides with Hydrogen Peroxide
Authors: Yamazaki Shigekazu 
Published: June 2006

Abstract
Methyltrioxorhenium-catalyzed oxidation of sulfides with hydrogen peroxide in ethanol has been found to be an efficient catalytic system for the selective formation of sulfoxides and sulfones. The oxidation using an equimolar amount of hydrogen peroxide afforded sulfoxides in excellent yield, and the use of two molar amounts of hydrogen peroxide gave sulfones quantitatively. Strongly deactivated sulfide, bis(4-nitrophenyl) sulfide, was converted smoothly to the corresponding sulfoxide and sulfone in excellent yields. The functional group in the side chain of sulfide such as a carbon–carbon double bond was not affected under the reaction conditions, and the sulfur atom was selectively oxidized.
Fluorescent α,β-Unsaturated Carbonyl Compounds and 2-Methylpyridines. Their Application to a Quantitative Analysis of Carnitine
Authors: Nakaya Ken-ichi , Funabiki Kazumasa , Shibata Katsuyoshi , Muramatsu Hiroshige , Matsui Masaki 
Published: June 2006

Abstract
α,β-Unsaturated carbonyl compounds and 2-methylpyridines containing a 4-(dialkylamino)phenyl substituent can be used as fluorescent labeling reagents for the quantitative analysis of carnitine. 6-(4-Aminophenyl)-3-cyano-4-[4-(diethylamino)phenyl]-2-methylpyridine showed the best properties among the synthesized reagents.
Novel Zirconium–Iron Multinuclear Complex Catalysts for Olefin Polymerizations
Authors: Mitani Makoto , Hayakawa Michiya , Yamada Tohru , Mukaiyama Teruaki 
Published: June 2006

Abstract
Novel zirconium–iron dinuclear complexes, [FcSiMe2(R1R2Cp)ZrCl2Cp] (Fc; Ferrocenyl, R1 = R2 = H; 2a, R1 = Me, R2 = H; 2b, R1 = R2 = Me; 2c, R1 = Ph, R2 = H; 2d), [FcSiMe2Cp{ZrCl2(Me5Cp)}] (3a), hafnium–iron dinuclear complex, [FcSiMe2Cp{HfCl2(Me5Cp)}] (3b) and zirconium–iron trinuclear complex, [ZrCl2(FcSiMe2Cp)2] (4), were synthesized and complexes 2d and 4 were characterized by an X-ray diffraction method. Olefin polymerizations were conducted by using these multimetallic zirconocene catalysts with the coexistence of methylaluminoxane or tetrakis(pentafluorophenyl)borates. The maximum catalytic activities of complexes 2, 3 and 4 were observed at low temperatures (15—45 °C) in ethylene polymerization, contrary to the conventional zirconocene catalyst ([ZrCl2Cp2]), showing the maximum activity at between 70—80 °C. A detailed investigation of ethylene polymerization and NMR measurements of the active species suggested that the interesting behavior of these complexes arose from an electronic cooperative effect between the zirconium and iron atoms. It was also revealed that complexes 2 were highly reactive toward propylene or diene in the copolymerization of ethylene and propylene or terpolymerization of ethylene, propylene and diene.
Preparation of Optically Active Diol Derivatives by the Enzymatic Hydrolysis of Cyclic Carbonates
Authors: Matsumoto Kazutsugu , Fuwa Seiji , Shimojo Megumi , Kitajima Hidehiko 
Published: June 2006

Abstract
A simple enzymatic method for the preparation of optically active 1,2- and 1,3-diol derivatives is disclosed. In the screening of enzymes, racemic 4-[(2-benzyloxy)ethyl]-1,3-dioxolan-2-one (1a) was enantioselectively hydrolyzed by porcine pancreas lipase (PPL) to give optically active (R)-1a and (S)-4-(benzyloxy)butane-1,2-diol (2a). The addition of 10% i-Pr2O to the reaction system dramatically improved the reactivity to afford optically pure (R)-1a in 31% yield. PPL also catalyzed the hydrolysis of several five-membered cyclic carbonates with high enatioselectivity. It is noteworthy that the increment of the carbon number of the substituents reflects the drastic increase in enantioselectivity. On the other hand, the hydrolyses of six- and seven-membered cyclic carbonates were also catalyzed by PPL. In particular, the reaction of a six-membered substrate enantioselectively proceeded. This reaction afforded optically active 1,3-diol derivatives which could not be directly prepared by hitherto known methods using hydrolytic enzymes.
Novel Degradation of Sugar Skeleton by Diazidation
Authors: Yokoyama Masataka , Kobayashi Naoki , Hachiya Takeshi , Kubo Misao , Togo Hideo 
Published: June 2006

Abstract
O-Benzylated acyclic sugars are allowed to react with azidotrimethylsilane in the presence of boron trifluoride–diethyl ether to afford the corresponding 1,1-diazido sugars, cyano sugars, and interestingly, 1,1-diazido sugars degradated at the 1-position of carbon.
Acid Suppressive Therapy Use on an Inpatient Internal Medicine Service
Authors: Pham Co QD , Regal Randolph E , Bostwick Thomas R , Knauf Kara S 
Published: June 2006

Background: Use of acid suppressant medications has increased in both frequency and breadth in recent years. Data have indicated that questionable use of acid suppressants for non-accepted indications is common. Objective: To assess the indications and prevalence of acid suppressants used by inpatients on admission and at discharge. Methods: A retrospective chart review of 213 patients admitted to the University of Michigan Hospital non-critical care general medical service was conducted. Relevant medical history, acid suppressant drug used, and indications were collected from both inpatient medical records and discharge medication lists. Results: Of the 213 patients reviewed, 29% were taking acid suppressants prior to admission, with 33% being proton pump inhibitors (PPIs). Once patients were admitted, acid suppressant use increased to 71% (152 of 213), with 84% PPIs, 11% histamine2-receptor antagonists, and 5% combination therapy. Based upon our criteria, only 10% (15 of 152) of those on acid suppressants were found to have an acceptable indication. In patients where any history of gastroesophageal reflux disorder (GERD) was deemed as an acceptable indication (32 other patients), 31% (47 of 152) had an acceptable indication. For the 137 patients with non-accepted indications, 29% had no discernable indication and 38% were prescribed acid suppressants for corticosteroid-associated or stress ulcer prophylaxis. A history of gastrointestinal bleeds or peptic ulcer disease of more than 3 months since initial diagnosis or documented exacerbation of symptoms comprised 8% of the population. The aforementioned group of GERD patients made up 23% of this group. Compared to the 29% of patients taking acid suppressants prior to admission, 54% (115 of 213) of patients were prescribed acid suppressants at discharge. If only recent exacerbations of GERD were deemed as long-term indications, 10% (12 of 115) of these patients were found to have accepted indications. If all GERDs were acceptable long-term indications, 27% (31 of 115) would have met criteria for acceptable outpatient use. Conclusions: There is considerable excess usage of acid suppressants in both the inpatient and outpatient settings.
Does Celecoxib Potentiate the Anticoagulant Effect of Warfarin? A Randomized, Double-Blind, Controlled Trial
Authors: Dentali Francesco , Douketis James D , Woods Karen , Thabane Lehana , Foster Gary , Holbrook Anne , Crowther Mark 
Published: June 2006

Background: The management of patients who are receiving warfarin therapy and have musculoskeletal problems that require treatment with a nonsteroidal antiinflammatory drug (NSAID) is problematic because NSAID use may increase the risk for bleeding. Cyclooxygenase-2 selective NSAIDs such as celecoxib may be less likely to promote gastrointestinal bleeding; however, there are concerns that they could potentiate the anticoagulation effect of warfarin. Objective: To determine whether celecoxib potentiates the anticoagulant effect of warfarin, as measured by the international normalized ratio (INR). Methods: We performed a randomized, controlled, crossover trial to assess the effect on INR of celecoxib versus codeine (control treatment) in 15 patients who were receiving warfarin therapy and required analgesic treatment for osteoarthritis. During Phase 1 of the study, patients were randomly allocated to receive celecoxib 200 mg/day or codeine phosphate 7–15 mg 3–4 times daily for 5 weeks. During Phase 2 of the study, patients stopped the first study medication and started the other study medication; there was no drug-free interval between phases. Weekly INR testing was performed during the 10 week study period. Adopting the intent-to-treat principle, we used generalized estimating equations to analyze the data. Results: There was no significant difference in the mean INR values during each 5 week treatment period when patients received either celecoxib or codeine. There was, therefore, insufficient evidence to reject the hypothesis that these 2 treatments had an equal effect on the INR (mean difference [95% CI] 0.10 [-0.04 to 0.24]; p=0.16) based on mean imputation. This finding was confirmed after we repeated the analysis with multiple imputations (mean difference [95% CI] 0.093 [-0.16 to 0.35]; p = 0.47). Conclusions: Our results suggest that treatment with celecoxib does not potentiate the INR when taken with warfarin. Larger randomized trials are warranted to address the effects of coadministered warfarin and celecoxib on clinical outcomes.
Drug Dosage Adjustments According to Renal Function at Hospital Discharge
Authors: van Dijk Elisabeth A , Drabbe Nathalie RG , Kruijtbosch Martine , De Smet Peter AGM 
Published: June 2006

Background: Adequate dosing of medication in renal impairment to prevent hospitalizations and adverse reactions is a growing concern in the aging society. There are several dosing guidelines available, but structural use is uncommon. Objective: To perform a retrospective analysis of the incidence of required versus implemented dosage adjustments according to guidelines in patients with renal insufficiency at discharge and evaluate specific determinants responsible for the percentage of overlooked dosage adjustments. Methods: Medication and laboratory data were collected from patients at discharge during February and November 2004. For patients with a calculated creatinine clearance less than 51 mL/min/1.73 m2, the necessity for dosage adjustments was evaluated by pharmacists. All data were collected for further research and subsequent statistical analysis. Results: At discharge, 237 of 647 (36.6%) patients had a calculated creatinine clearance less than 51 mL/min/1.73 m2. Dosage adjustment based on renal function was necessary in 411 of 1718 (23.9%) of prescriptions. These adjustments were performed in 242 (58.9%) prescriptions and not performed in 169 (41.1%) cases. The risk of not adjusting the dosage was significantly associated with serum creatinine levels greater than 1.71 mg/dL and creatinine clearance less than 35 mL/min/1.73 m2 (p <0.05). The risk of not adjusting the dosage was also significantly associated with drugs producing severe consequences when dosing guidelines were overlooked (p < 0.05). Conclusions: In patients with a calculated creatinine clearance less than 51 mL/min/1.73 m2, dosing according to their renal function can be improved. Because of the need and the association found in this study, an alert system could help prescribers and pharmacists to adapt drug dosage in patients with renal impairment.
N-Cadherin Transsynaptically Regulates Short-Term Plasticity at Glutamatergic Synapses in Embryonic Stem Cell-Derived Neurons
Authors: Jüngling Kay , Eulenburg Volker , Moore Robert , Kemler Rolf , Lessmann Volkmar , Gottmann Kurt 
Published: June 2006

The cell adhesion molecule N-cadherin has been proposed to regulate synapse formation in mammalian central neurons. This is based on its synaptic localization enabling alignment of presynaptic and postsynaptic specializations by an adhesion mechanism. However, a potential role of N-cadherin in regulating synaptic transmission has remained elusive. In this paper, a functional analysis of N-cadherin knock-out synapses was enabled byin vitroneuronal differentiation of mouse embryonic stem cells circumventing the early embryonic lethality of mice genetically null for N-cadherin. In ourin vitrosystem, initial synapse formation was not altered in the absence of N-cadherin, which might be attributable to compensatory mechanisms. Here, we demonstrate that N-cadherin is required for regulating presynaptic function at glutamatergic synapses. An impairment in the availability of vesicles for exocytosis became apparent selectively during high activity. Short-term plasticity was strongly altered with synaptic depression enhanced in the absence of N-cadherin. Most intriguingly, facilitation was converted to depression under specific stimulation conditions. This indicates an important role of N-cadherin in the control of short-term plasticity.To analyze, whether N-cadherin regulates presynaptic function by a transsynaptic mechanism, we studied chimeric cultures consisting of wild-type neocortical neurons and ES cell-derived neurons. With N-cadherin absent only postsynaptically, we observed a similar increase in short-term synaptic depression as found in its complete absence. This indicates a retrograde control of short-term plasticity by N-cadherin. In summary, our results revealed an unexpected involvement of a synaptic adhesion molecule in the regulation of short-term plasticity at glutamatergic synapses.