bluuebunny/crossref_metadata_2025_split huggingface dataset:
Attractive Potential Effect on the Rotational Correlation Times for Benzene-d6 in Organic Solvents
Authors: Wakai Chihiro , Nakahara Masaru 
Published: June 2006

Abstract
2H NMR spin-lattice relaxation times have been measured to obtain the rotational correlation times τ2R for benzene C6D6 (50 mol m−3) in various organic solvents, such as benzene (C6H6), hexane, decane, carbon tetrachloride, chloroform, dichloromethane, methanol, ethanol, 1-propanol, 1-butanol, and acetonitrile over the widest possible range of temperature. Plots of the determined values of τ2R against solvent viscosity η divided by temperature T are linear in the apolar and polar aprotic solvents, as predicted by the Stokes–Einstein–Debye (SED) law. However, the plots of τ2R vs. η/T in the alcohols are concave upward, the slope in the high temperature region being ca. 2 times as large as that in the low temperature region. The nonlinearity and the decrease in the slope reflect the influence of the hydrogen-bonded solvent structure. For the benzene rotation in solutions, fairly good positive linear correlations are found between the slopes and the negative dissolution enthalpies at infinite dilution at room temperature. These results indicate an important role played by attractive solute–solvent interactions in controlling the molecular rotation in solution.
Isolation and Structural Characterization of Complexes Formed in the Reactions of [{C5H4(SiMe3)}2Fe2(CO)4] and [{1,3-C5H3(SiMe3)2}2Fe2(CO)4] with Elemental Sulfur
Authors: Yamada Mikiya , Tobita Hiromi , Inomata Shinji , Ogino Hiroshi 
Published: June 2006

Abstract
The reactions of [CpS12Fe2(CO)4] and [CpS22Fe2(CO)4] with elemental sulfur afforded a tetrairon cluster containing two end-on type S2 ligands [CpS14Fe4S6] (1) and a diiron complex containing an end-on type S2 and a side-on type S2 ligands [CpS22Fe2S4] (2), respectively, where CpS1 and CpS2 stand for mono- and bis(trimethylsilyl)cyclopentadienyl ligands, respectively. From these results and the previously reported results which were obtained for the reactions of [Cp2Fe2(CO)4] and [Cp*2Fe2(CO)4] with elemental sulfur, it is suggested that [Cp′2Fe2S4] is an intermediate to give tetrairon sulfur clusters, where Cp* and Cp′ denote pentamethylcyclopentadienyl and substituted cyclopentadienyl ligands, respectively. X-Ray crystal structure analysis was carried out for the compounds 1 and 2. Crystallographic data are as follows: 1: Monoclinic, P21/c, a = 17.302(6), b = 18.646(3), c = 15.310(4) Å, β = 120.71(2)°, V = 4246(2) Å3, Z = 4, and R = 0.061 for 5850 reflections with |Fo| &gt; 3σ(Fo); 2: Triclinic, space group , a = 12.602(2), b = 12.891(2), c = 11.401(1) Å, α = 114.52(1), β = 95.45(1), γ = 88.39(1)°, V = 1677.5(4) Å3, Z = 2, and R = 0.046 for 7343 reflections with |Fo| &lt; 3σ(Fo).
Effects of the Molar Mass of a Solute on Permeability through Poly(vinyl alcohol) Gel Membranes
Authors: Yonese Masakatsu , Kondo Masatoshi , Miyata Isamu , Kugimiya Sin-ichi , Sato Shizuko , Inukai Masao 
Published: June 2006

Abstract
The effects of the molar masses of solutes on permeability through poly(vinyl alcohol) PVA gel membranes were studied using polyethylene glycol having a wide range of molar masses and other solutes, such as electrolytes, glucose, and maltose. Furthermore, the effects of the network structure and fixed charges on the permeability were studied using opaque, transparent, and charged PVA gels. The permeability coefficients of solutes through PVA gel membranes (P) depended on the hydrodynamic radius of the solute (d0) and the mesh sizes of the network (ξ). When interactions between the matrix and the solute were negligible, the normalized permeability coefficients (P/D0) were found to be the scaling function of ξ/d0.
Adsorption of CO2, CH3OH, and H2O on Fe(III)-Substituted Calcium Hydroxyapatites
Authors: Ishikawa Tatsuo , Saito Hiroshi , Yasukawa Akemi , Kandori Kazuhiko 
Published: June 2006

Abstract
Calcium hydroxyapatites (CaHAP) substituted with Fe3+ ions of different atomic ratios Fe/(Ca + Fe) = XFe from 0 to 0.23 were synthesized and characterized by various methods. The number of Ca2+ ions in CaHAP substituted by one Fe3+ ion was higher than one, implying that the formation of cation vacancies and the protonation of PO43− ions are caused by Fe(III)-substitution. XFe of the surface layer of the particles determined by XPS was less than the total XFe. IR spectra of Fe(III)-substituted CaHAP contain a band at 3707 cm−1 assigned to the surface Fe–OH groups in addition to the surface P–OH bands at 3688, 3677, and 3658 cm−1. With an increase in XFe, the amount of irreversible adsorption of CO2 decreased whilst those of CH3OH and H2O first decreased and then increased. IR results showed that the surface Fe–OH groups act as stronger irreversible adsorption sites for CO2 and CH3OH compared to the surface P–OH groups.
Unimolecular Dissociation Kinetics of Benzene Cluster Ions
Authors: Ohashi Kazuhiko , Adachi Kei , Nishi Nobuyuki 
Published: June 2006

Abstract
The “unimolecular” dissociation processes of benzene cluster ions prepared by resonant 2-photon ionization (R2PI) of neutral clusters were investigated by using a time-of-flight mass spectrometer equipped with a reflectron. The dissociation rates were determined for fast-decay processes (kfast) in the acceleration region and slow dissociations (kslow) in the drift region of the spectrometer. The ejection of one neutral molecule was a dominant dissociation channel of small (C6H6)n+ in the drift region; in addition, the ejection of two molecules was observed for n − 2 ≥ 14. These size-specific dissociation channels and the size dependence of the kslow values imply a closing of the first shell of (C6H6)n+ at n = 14. The magnitude of both kfast and kslowwas found to be independent of the excess energy upon R2PI, suggesting rapid cooling of the nascent hot ions by prompt dissociation within the laser focus. For slow dissociation within a well-defined time window, the measured values of kslow were compared with those calculated according to a statistical theory of unimolecular reaction. The comparison deduced the average internal energies of (C6H6)n+ at ca. 1 μs after preparation.
Pressure Effect on Inter- and Intramolecular Vibrations of the p-Xylene Crystals
Authors: Shimizu Fumio , Yoshikai Kazumasa , Kawano Hiroshi , Nibu Yoshinori , Shimada Hiroko , Shimada Ryoichi 
Published: June 2006

Abstract
The Raman active inter- and intramolecular vibrations of the [1H10]- and [2H10]p-xylene crystals were studied under various pressures between 1 atm and 7.5 GPa. The pressure effect of the frequency of the Raman bands due to the intermolecular vibrations indicates that the coupling between the intramolecular torsional vibration of the methyl group and the intermolecular rotational vibrations takes place under about 1 and 2.5 GPa in the [1H10]- and [2H10]p-xylene crystals, respectively. The calculated pressure-induced frequency shift of the intramolecular vibrations explains fairly well the observed frequency shifts and supports the conclusion given in the previous work that the contribution of the first-order differential of the intermolecular potential to the pressure-induced frequency shift is vanishingly small when the potential is well approximated.
Spectroscopic Characterization and Biological Potential of Palladium(II) Complexes of Benzylidenehydrazinecarboxamide or -carbothioamide
Authors: Fahmi Nighat , Saxena Chitra , Singh Ranvir V 
Published: June 2006

Abstract
In this article a brief account of the synthesis, stereochemistry, and biochemical behavior of palladium(II) complexes of benzylidenehydrazinecarboxamide or -carbothioamide is presented. The bimolar addition and substitution products have been characterized by elemental analyses, conductance measurements, molecular-weight determinations, magnetic susceptibilities, and spectral studies viz., IR, 1H NMR, 19F NMR, and UV. The data support the binding of sulfur or oxygen and nitrogen to the palladium in and (X is O or S) types of complexes. The square-planar geometry has been proposed. The representative free ligands () and their respective metal complexes were tested in vitro against a number of microorganisms to assess their antimicrobial properties and in vivo to test their sterilizing potential. The results are indeed positive.
Elucidation of Salt Effects on the Indicator Acidity in Acetonitrile
Authors: Hojo Masashi , Hasegawa Hiroshi , Yoneda Hitoshi 
Published: June 2006

Abstract
The salt effects on the proton-transfer from CF3COOH to an acid-base indicator, ‘Methyl Yellow’ [p-(dimethylamino)-azobenzene], were examined in acetonitrile by means of spectrophotometry. The addition of LiClO4 to the indicator (Ind) and CF3COOF mixture (both 2.0 × 10−4 mol dm−3) caused an increase and a successive decrease in the absorbance (λmax = 514 nm) of IndH+. The promoted increase of the IndH+ concentration with increasing concentration of LiClO4 was explained on a quantitative basis concerning the formation of a triple cation, CF3COO−(Li+)2, as well as an ion pair, CF3COO−Li+: Ind–CF3COOH + 2 Li+ IndH+ + CF3COO−(Li+)2. The successive decrease in the absorbance at 514 nm with a large excess of LiClO4 was attributed to an ion-exchange reaction: IndH+ + Li+ IndLi+ + H+. The addition of NaClO4 to Ind–CF3COOH caused only an increase in the IndH+ concentration, and no deprotonation from IndH+. Alkaline-earth metal ions (M2+ = Mg2+, Ca2+, Sr2+, and Ba2+) promoted protonation by the formation of complex species, CF3COO−M2+. Although distinct deprotonation from IndH+ was observed with Mg(ClO4)2, no deprotonation occurred with Ba(ClO4)2. The effects of the chloride ion (Et4NCl) on deprotonation from IndH+ (In + CF3SO3H) were explained by the formation of homoconjugated species (HCl2−), and not by the mere formation of HCl. The apparent changes in pH or the Hammett acidity function with the presence of various salts were elucidated by the ‘complex’ formation in acetonitrile.
Electron Transfer Reaction Accompanied by a Structural Change. In the Case of Reaction with [Ru(NH3)5(butyl sulfoxide)]2+ and cis-[Ru(NH3)4(pyridine-4-carboxamide)2]3+
Authors: Sano Mitsuru , Sago Hiromitsu , Tomita Atsuko 
Published: June 2006

Abstract
The oxidation of [Ru(NH3)5(butyl sulfoxide)]2+ by cis-[Ru(NH3)4(pyridine-4-carboxamide)2]3+ has been studied as a case of an electron transfer reaction accompanied by a structural change. Even in an excess of one of the reaction partners, the reaction shows complex kinetic behavior. Treatment of the experimental data points to a mechanism in which the first step is an up-hill electron transfer between the complexes and in which the second step involves isomerization of the unstable sulfoxide complex produced in the first step.
Motivation, Governance, and the Viability of Hybrid Forms in Open Source Software Development
Authors: Shah Sonali K. 
Published: June 2006

Open source software projects rely on the voluntary efforts of thousands of software developers, yet we know little about why developers choose to participate in this collective development process. This paper inductively derives a framework for understanding participation from the perspective of the individual software developer based on data from two software communities with different governance structures.In both communities, a need for software-related improvements drives initial participation. The majority of participants leave the community once their needs are met, however, a small subset remains involved. For this set of developers, motives evolve over time and participation becomes a hobby. These hobbyists are critical to the long-term viability of the software code: They take on tasks that might otherwise go undone and work to maintain the simplicity and modularity of the code. Governance structures affect this evolution of motives. Implications for firms interested in implementing hybrid strategies designed to combine the advantages of open source software development with proprietary ownership and control are discussed.
Fondaparinux for Thromboembolic Treatment and Prophylaxis of Heparin-Induced Thrombocytopenia
Authors: Efird Leigh E , Kockler Denise R 
Published: June 2006

Objective: TO review literature evaluating the use of fondaparinux for thromboembolic treatment and prophylaxis in patients with heparin-induced thrombocytopenia (HIT). Data Sources: A MEDLINE search (1966–February 2006) was conducted using the search terms fondaparinux, heparin, low-molecular-weight heparin, and thrombocytopenia to identify English-language articles. Additional sources were identified from bibliographies of select articles and the manufacturer. Data Synthesis: Fondaparinux, a pentasaccharide that selectively inhibits factor Xa, has been reported to have negligible or no cross-reactivity in vitro with HIT antibodies. Thromboembolic treatment and prophylaxis with fondaparinux in patients with HIT has been described. Three cases reported patients who were successfully treated for thromboembolic events with fondaparinux after developing HIT during therapy with unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH). Another report showed positive outcomes using fondaparinux for prophylaxis in a patient who had previously developed HIT after receiving UFH. Moreover, 2 case series, one using fondaparinux for prophylaxis in patients with a previous diagnosis of HIT and the other using fondaparinux for treatment in patients who developed HIT while receiving UFH or LMWH, reported normal platelet counts during fondaparinux treatment. Finally, results of a retrospective review demonstrated that fondaparinux prevented thromboembolic events or recurrent thrombocytopenia in patients with a prior HIT diagnosis. Conclusions: Limited data support the use of fondaparinux for thromboembolic treatment or prophylaxis in patients with antibody assay–confirmed HIT who do not have a contraindication for fondaparinux use. Randomized controlled trials have not been published; therefore, questions remain regarding efficacy, safety, optimal doses, treatment duration, and incidence of thromboembolic events when fondaparinux is used in this setting. Prospective trials evaluating the efficacy and safety of fondaparinux in this patient population need to be conducted to answer these questions.
The Evolution of Mobile DNAs: When Will Transposons Create Phylogenies That Look As If There Is a Master Gene?
Authors: Brookfield John F Y , Johnson Louise J 
Published: June 2006

Abstract
Some families of mammalian interspersed repetitive DNA, such as the Alu SINE sequence, appear to have evolved by the serial replacement of one active sequence with another, consistent with there being a single source of transposition: the “master gene.” Alternative models, in which multiple source sequences are simultaneously active, have been called “transposon models.” Transposon models differ in the proportion of elements that are active and in whether inactivation occurs at the moment of transposition or later. Here we examine the predictions of various types of transposon model regarding the patterns of sequence variation expected at an equilibrium between transposition, inactivation, and deletion. Under the master gene model, all bifurcations in the true tree of elements occur in a single lineage. We show that this property will also hold approximately for transposon models in which most elements are inactive and where at least some of the inactivation events occur after transposition. Such tree shapes are therefore not conclusive evidence for a single source of transposition.
Environmental Controls of UV‐B Radiation in Forested Streams of Northern Michigan
Authors: Frost Paul C. , Mack Alyson , Larson James H. , Bridgham Scott D. , Lamberti Gary A. 
Published: June 2006

ABSTRACTWe examined UV‐B radiation flux and its environmental control within and among streams of northern Michigan. UV‐B flux was estimated in streams by plastic dosimetry strips, which allow for the simultaneous and repeated in situ measurement of solar radiation. During the summer of 2004, UV‐B flux was measured across depth gradients and along longitudinal transects in seven streams, which were chosen to encompass a range of dissolved organic carbon (DOC) concentrations and canopy cover. Attenuation coefficients of UV‐B (Kd UV‐B) were estimated using plastic dosimeters placed along a depth gradient. Kd UV‐B were positively correlated with DOC concentration and similar to values obtained with laboratory and in situ spectrometry. Along 100 m longitudinal transects, UV‐B flux varied along all streams regardless of their canopy cover and DOC concentration. Within‐stream fluxes of UV‐B were correlated to canopy cover in the only two streams that both had relatively low DOC concentration and variable canopy cover. Large differences were found among streams in the average UV‐B flux (corrected for incident solar flux) reaching the dosimeters at 5 cm depth. These among‐stream differences were largely accounted for by the stream width, canopy cover, and DOC concentration. Our results illustrate an inherent variability in UV‐B flux within and among streams of northern Michigan that is strongly tied to the interactions of DOC concentration, stream size and riparian vegetation.
Light‐driven Hydrogen Production by a Hybrid Complex of a [NiFe]‐Hydrogenase and the Cyanobacterial Photosystem I
Authors: Ihara Masaki , Nishihara Hirofumi , Yoon Ki‐Seok , Lenz Oliver , Friedrich Bärbel , Nakamoto Hitoshi , Kojima Kouji , Honma Daisuke , Kamachi Toshiaki , Okura Ichiro 
Published: June 2006

ABSTRACTIn order to generate renewable and clean fuels, increasing efforts are focused on the exploitation of photosynthetic microorganisms for the production of molecular hydrogen from water and light. In this study we engineered a ‘hard‐wired’ protein complex consisting of a hydrogenase and photosystem I (hydrogenase‐PSI complex) as a direct light‐to‐hydrogen conversion system. The key component was an artificial fusion protein composed of the membrane‐bound [NiFe] hydrogenase from the β‐proteobacterium Ralstonia eutropha H16 and the peripheral PSI subunit PsaE of the cyanobacterium Thermosy‐nechococcus elongatus. The resulting hydrogenase‐PsaE fusion protein associated with PsaE‐free PSI spontaneously, thereby forming a hydrogenase‐PSI complex as confirmed by sucrosegradient ultracentrifuge and immunoblot analysis. The hydrogenase‐PSI complex displayed light‐driven hydrogen production at a rate of 0.58 μmol H2· mg chlorophyll−1· h−1. The complex maintained its accessibility to the native electron acceptor ferredoxin. This study provides the first example of a light‐driven enzymatic reaction by an artificial complex between a redox enzyme and photosystem I and represents an important step on the way to design a photosynthetic organism that efficiently converts solar energy and water into hydrogen.
Design and Trial of a Computer-Assisted Lesson in Rhythm
Authors: Placek Robert W. 
Published: June 2006

For this study, a computer-assisted lesson for teaching selected behaviors that are related to the area of rhythm perception was designed and programed for students majoring in elementary education. The lesson's effects on students were then determined by testing the lesson with subjects from the University of Illinois at Urbana-Champaign. The investigator used the computer-based Education Research Laboratory at the University of Illinois to design and program the lesson, set it into operational form, and test it. The TUTOR language and PLATO III system were used, consisting of a keyset, cathode-ray tube, and random-access slide selector. Also used was a random-access audio device designed for the PLATO IV. Two program objectives were stated for the CAI lesson, called RHYTHM: (1) The student can demonstrate a knowledge of the function of basic rhythmic notation, and (2) the student can demonstrate a knowledge of the relation of rhythmic notation to aural rhythmic patterns. During the two-week experimental program, data were collected by the computer and printed out, then analyzed and reported. The data included: (1) total time spent and amount of program covered, (2) amount of time on each main routine, (3) number of tries and OK or NO responses from the computer, and (4) special keys pressed within an exercise problem. At the end of each lesson session, the investigator interviewed individual students to find out their opinions of the enjoyable and frustrating aspects of the CAI lesson. Participating students generally felt that the lesson was enjoyable and valuable. They especially valued PLATO'S ability to feedback and to define a task, demand input, and quickly judge input. As a whole, students felt they had learned the basic behaviors related to notation encountered in the lesson. Most students felt that certain messages of the audio output were transmitted poorly.
Grading Students in Performing Groups: A Comparison of Principals' Recommendations with Directors' Practices
Authors: McCoy Claire Wehr 
Published: June 2006

The purpose of this study was to examine how directors determine grades for students in high school band and choral classes and how the directors' grading systems compare with grading systems proposed by principals. Data were obtained from responses to questionnaires sent to band directors, choral directors, and principals at 98 randomly selected Illinois high schools. Results showed that directors relied most heavily on nonmusic criteria to determine grades; psychomotor criteria related to performance were the next most heavily weighted, followed by affective and cognitive criteria. In contrast, the principals' proposed grading systems assigned the greatest weight to psychomotor criteria, followed by nonmusic, cognitive, and affective criteria. Analyses of variance revealed significant differences ( p > .05) between the two groups of directors and principals: Principals placed more weight on cognitive criteria and on basic performance technique and less weight on attendance at concerts and behavior than did directors. Directors with 5 or more years' experience placed more weight on psychomotor criteria than did directors with fewer than 5 years of experience.
The Aural Perception of Similarity in Nontraditional Chords Related by Octave Equivalence
Authors: Gibson Don B. 
Published: June 2006

The purpose of this study was to determine the aural significance of the octave-equivalence I assumption, which is essential to the notion of “pitch class.” To address this question, the author developed a series of 22 experimental items, each consisting of two pairs of nontraditional chords presented harmonically. The two chords of one of the pairs in each item contained the same pitch classes, with each pitch class in the second chord of that pair in a different octave than it had been in the first chord. The two chords in the other pair did not have identical pitch classes. These chord pairs (A, A1) and (A, B) were constructed so that a given chord (A) would be compared alternately with two other chords (A1 and B). The subjects were to judge which pair sounded more alike. The items included chords ranging in size from three to nine pitches. The number of new pitches in Chord B was also treated as a variable in the experiment. An Apple IIe, equipped with three ALF MC16 Music Cards, presented a random ordering of the experimental items to each of the 51 music majors and 50 nonmusic majors who completed the experiment. Statistical analysis of the 2, 222 individual item responses demonstrated some evidence of the perception of similarity in chords containing six, seven, and eight pitches. The relative number of new pitches in Chord B did not seem to affect the responses of the subjects. Additionally, the responses of the majors did not differ significantly from those of the nonmajors. There was also a significant tendency for both majors and nonmajors to choose the first pair of chords more frequently than the second pair. This tendency was more pronounced for the majors than for the nonmajors. Additional data provided by a group of 26 professional musicians supported the results obtained in this study.