bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sound generation in the searobin (Prionotus carolinus), a fish with alternate sonic muscle contraction
Authors: Connaughton Martin A. 
Published: April 2004

SUMMARY
The Northern searobin (Prionotus carolinus) contracts its paired sonic muscles alternately rather than simultaneously during sound production. This study describes this phenomenon and examines its effect on sound production by recording sound and EMGs during voluntary and electrically stimulated calls. Sounds produced by a single twitch resulted in a two-part sound representing contraction and relaxation sounds. The relaxation sound of one twitch coincides with the contraction sound of the next twitch of that muscle. Maximum amplitude of evoked sounds occurs between 100 Hz and 140 Hz,approximately half the fundamental frequency of a voluntarily calling fish. The muscle is capable of following electrical stimulation at frequencies of up to 360 Hz. Rapid damping and response over a wide frequency range indicate that the swimbladder is a highly damped, broadly tuned resonator. A consequence of alternate contraction is a 3.3 dB loss in acoustic pressure due to the contraction of a single sonic muscle at a time. This decrease in amplitude is offset by a doubling of fundamental frequency and a constructive interaction between the sides of the bladder, resulting in increased amplitude of each unilaterally produced sound. The alternate contraction of the bilateral sonic muscles represents a novel solution to the inherent trade-off between speed and force of contraction in rapidly contracting sonic muscles.
Laser scanning cytometry and tissue microarray analysis of salinity effects on killifish chloride cells
Authors: Lima Raquel N. , Kültz Dietmar 
Published: April 2004

SUMMARYThe effects of salinity on chloride cells (CC) and Na+/K+-ATPase content in gill epithelium of euryhaline killifish Fundulus heteroclitus were analyzed using laser scanning cytometry (LSC) and tissue microarrays (TMAs). Salinity acclimations consisted of acute transfer from freshwater (FW) to 1× seawater (SW) and gradual transfer from FW to 2.4× SW. Suspensions of dissociated gill epithelial cells were stained with DASPMI and evaluated using LSC. CC number and volume are proportional to external salinity, being lower in FW(0.5±0.2×105 and 405±32 μm3,respectively) and higher after 5 weeks in 2.4× SW(3.7±0.9×105 and 2697±146 μm3,respectively). TMAs were constructed from fixed gill tissues and developed using antibody for Na+/K+-ATPase to visualize CCs in situ and compare their characteristics with isolated CCs. Na+/K+-ATPase content per CC increases transiently (from 2.2±0.5×106 to 4.8±1.1×106relative fluorescence units, RFU) after 1 week of acute acclimation to 1× SW but returns to baseline values(2.4±0.5×106 RFU) within 5 weeks. In contrast, gradual acclimation to 2.4× SW permanently increases Na+/K+-ATPase content per CC (from 2.0±0.8×106 to 6.7±2.7×106 RFU after 5 weeks). CC size in situ did not correlate well to salinity because of basolateral membrane infoldings. Taken together, these data suggest that euryhaline fishes are capable of sensing environmental salinity to utilize transient short-term and permanent long-term adaptations for coping with salinity changes. These results also demonstrate the power of LSC and TMA for comparative biology.
Bumblebee search time without ultraviolet light
Authors: Dyer Adrian G. , Chittka Lars 
Published: April 2004

SUMMARY
Bees often facilitate pollination of important greenhouse crops. Individual bumblebees Bombus terrestris were therefore tested in an indoor flight arena to evaluate whether or not search time to find flowers was influenced by the inclusion or exclusion of ultraviolet radiation. Plastic model flowers of similar spectral properties to flowers of tomato Lycopersicon esculentum Mill. were used to evaluate bee search efficiency. The results show that bumblebees perceive when ultraviolet radiation is either removed or added to an illumination source; however, the bumblebees rapidly learn to find model flowers with equal efficiency in either illumination environment. The behavioural results are interpreted in relation to a colorimetric analysis showing how bumblebees are capable of using their visual system to forage efficiently in environments that exclude ultraviolet radiation.
Metabolic rates of captive grey seals during voluntary diving
Authors: Sparling Carol E. , Fedak Michael A. 
Published: April 2004

SUMMARYThe energetic cost of diving in marine mammals is a difficult value to derive given the problems of assessing metabolic rate for an animal at sea. Nevertheless, it is fundamental to our understanding of the foraging strategies of air-breathers exploiting underwater food sources. We measured the metabolic rates of eight captive grey seals, voluntarily diving in a quasi-natural setting. Oxygen consumption during post-dive surface periods was measured using open-flow respirometry, and dive behaviour of the seals was recorded using time depth recorders (TDRs). Mean diving metabolic rate (DMR)for both adults and juveniles was 1.7 times the predicted standard metabolic rate of terrestrial animals of equal size. For all animals, DMR was lower than the rate of metabolism measured whilst they were resting at the water's surface. On a dive-by-dive basis, DMR decreased with dive duration but increased with mean swim speed. Regressing the maximum 5% of DMRs against dive duration resulted in a significant negative relationship that was not significantly different from the relationship between the calculated maximum rate of aerobic metabolism and dive duration, suggesting that these seals were diving within, and up to, their aerobic limits. We developed a model that allows the prediction of DMR from information on dive behaviour of the type routinely collected in telemetry studies of wild seals. The model accurately predicts DMR using behavioural data from periods of diving with known metabolism data. This model can be used to predict the at-sea metabolic rate of wild grey seals, an important input into ecosystem models.
A FRET Study of Guest Delivery to Concanavaline A by Supramolecular Hosts Composed of an Adamantyl-Appended Cyclophane and Saccharide-Branched Cyclodextrins
Authors: Hayashida Osamu , Hamachi Itaru 
Published: April 2004

Abstract
Water-soluble supramolecular hosts composed of an adamantyl-appended cyclophane and glucosyl- or maltosyl-α-cyclodextrins were developed as a transporter for fluorescent guest toward Concanavaline A (Con A), α-d-glucoside-binding lectin. The delivery of perylene as a model guest from aqueous media to Con A surfaces was monitored by fluorescence resonance energy transfer (FRET) spectroscopy.
An Optically Active Hydrogel Composed of Cross-linked Poly(4-carboxyphenyl isocyanide) with a Macromolecular Helicity Memory
Authors: Ishikawa Masayoshi , Taura Daisuke , Maeda Katsuhiro , Yashima Eiji 
Published: April 2004

Abstract
Hydrogels composed of a poly(phenyl isocyanide) bearing a carboxylate group with a macromolecular helicity memory were synthesized by cross-linking with achiral diamines in water, and the obtained hydrogels were found to maintain their memory even at 90 °C in water, although the helical polymer before the cross-linking lost its memory at high temperature.
A New Method for the Esterification of Carboxylic Acids with Various Alcohols by Using Di-2-thienyl Carbonate, a New Coupling Reagent
Authors: Mukaiyama Teruaki , Oohashi Yoshiaki , Fukumoto Kentarou 
Published: April 2004

Abstract
Esterification of carboxylic acids with alcohols by using di-2-thienyl carbonate in the presence of a catalytic amount of 4-(dimethylamino)pyridine (DMAP) proceeded smoothly under mild conditions to afford the corresponding esters and 2(5H)-thiophenone in good to high yields.
Distinction of Acid-type on Solid Acid Surface by Comparison of Adsorption Heats of Nitrogen and Argon
Authors: Matsuhashi Hiromi , Yamagata Keiko , Arata Kazushi 
Published: April 2004

Abstract
The heats of adsorption of N2 and Ar on solid acids were compared by applying the Clausius–Clapeyron equation to isotherms. The heats on H-mordenite and H4SiW12O40 supported on SiO2 decreased gradually with increasing the adsorption amount in parallel with each other, while sulfated zirconia and Al2O3 gave large difference between N2 and Ar in low adsorption range more than 30 and 15 kJ mol−1, respectively, enabling the result to distinguish the Brönsted- and Lewis-acid types.
Aromatic Iodine-Assisted Self-assembly of a Cobalt(II) Complex of Ferron (Ferron = 7-iodo-8-hydroxyquinoline-5-sulfonate)
Authors: Zhang Feng , Li Yi-Zhi , Gao Xu , Chen Hui-Lan , Liu Qi-Tao , Odani Akira , Yamauchi Osamu 
Published: April 2004

Abstract
A dimeric Co(II) complex of ferron (=7-iodo-8-hydroxyquinoline-5-sulfonate) was isolated as crystals and structurally characterized. Weak I···H and I···C interactions involving the iodoquinoline rings and complementary steric requirements for I···I contacts led to self-assembly of the complex, which indicates versatile nature of the iodine atom in intermolecular interactions.
Surface Reactions on MoO3 Induced by Tunable Pulse Infrared Free Electron Laser
Authors: Sato Shisuke , Niimi Hironobu , Suzuki Shushi , Chun Wang-Jae , Irokawa Katsumi , Kuroda Haruo , Asakura Kiyotaka 
Published: April 2004

Abstract
We have carried out ethanol conversion reactions on the MoO3 under the pulse infrared irradiations (period = 2 s) with several wavelengths emitted from free-electron-laser. We found a piece of evidence to show the dependence of activities in the ethanol conversion rate on the infrared wavelengths. When the wavelength was tuned to 967 cm−1, which corresponded to the absorption frequency of 0.167 nm Mo=O bond, C2H5OH was converted mainly to C2H4 with CH3CHO as a minor product while no reaction occurred at 1200 cm−1 where no resonant vibration mode of MoO3 was present. The reaction products were different from those produced in thermal reactions.
New Epoxide Molten Salts: Key Intermediates for Designing Novel Ionic Liquids
Authors: Demberelnyamba D , Yoon Sang Jun , Lee Huen 
Published: April 2004

Abstract
Room temperature ILs, based pyridinium and imidazolium cations containing glycidyl (2,3-epoxypropyl) chains have been synthesized in an attempt to design new functionalized ILs. The epoxides in glycidyl ILs comprise an extremely versatile group of intermediates and can react with a large range of nucleophiles, electrophiles and others, resulting in the production of novel ILs with different functional groups.
Mechanistic Study on the Radiolysis of Dilute PVA Aqueous Solutions
Authors: Zhang Shu-Juan , Yu Han-Qing 
Published: April 2004

Abstract
The mechanisms behind the radiolytic degradation of PVA in dilute aqueous solutions were elucidated. The formation of hydrogen as the main gaseous product, as well as the analysis of degradation intermediates by NMR, FTIR, UV–vis, and viscosity determination demonstrated that the mechanism of the radiolytic degradation of PVA was hydrogen abstraction, followed by chain scission.
Layer-by-Layer Assembly of Low Molecular Weight Dye/Enzyme Composite Thin Films for Biosensor Appilcation
Authors: Li Yangmei , Chen Zhichun , Jiang Xiuming , Lin Xianfu 
Published: April 2004

Abstract
The multilayer films of low molecular weight dye methylene blue (MB) and horseradish peroxidase (HRP) were fabricated by layer-by-layer assembly through electrostatic force. MB was pre-absorbed with anionic polyelectrolyte poly(sodium-p-styrenesulfonate) (PSS). The MB/HRP multilayer film-modified Au electrode functioned as a biosensor for H2O2.
Acidic Properties and Catalytic Activities of Sol–gel Derived Zn2SiO4
Authors: Shino Yoritsugu , Nakabayashi Hirotoshi 
Published: April 2004

Abstract
The ZnO–SiO2 binary oxides prepared by sol–gel method were calcined at various temperatures in order to reveal the relations between the surface properties as acid catalysts and the bulk structures. It was found that the catalytic activities and the acid amounts remarkably increased when the Zn2SiO4 phase was just formed by the calcination at 1173 K.
Potassium Ion Selective Signaling Based on Intramolecular Dimer Formation of Biscrown Ether Azochromophore —Chemosensor Exhibiting Forceps Function—
Authors: Hayashita Takashi , Murakami Akiko , Teramae Norio 
Published: April 2004

Abstract
A novel bisbenzo-15-crown-5 azochromophore, 2, which exhibits forceps function, has been designed. 2 shows selective UV–vis spectral response for K+ in acetonitrile, which is based on the exciton interaction of the two azochromophores upon forming an intramolecular sandwich complex with K+.
Anomalous Ring Cleavage of 1,3-Dithiole- and 1,3-Diselenole-2-thiones under the Cross-Coupling Conditions Using Triethyl Phosphite
Authors: Iyoda Masahiko , Watanabe Ryoji , Miyake Yosihiro 
Published: April 2004

Abstract
The ring cleavage of 4,5-ethylenedioxy-1,3-dithiole- and -1,3-diselenole-2-thiones, followed by the reaction with 4,5-bis(methoxycarbonyl)-1,3-diselenole-2-one took place under the phosphite-mediated cross-coupling conditions to afford 2-thioxo- and 2-(selenoxomethylidene)-1,3-diselenoles. The structure of 4,5-bis(methoxycarbonyl)-2-(thioxoalkylidene)-1,3-diselenole was confirmed by X-ray analysis.
Comparison of Objective Methods for Assessment of Annoyance of Low Frequency Noise with the Results of a Laboratory Listening Test
Authors: Poulsen Torben 
Published: April 2004

Subjective assessments made by test persons were compared to results from a number of objective measurement and calculation methods for the assessment of low frequency noise. Eighteen young persons with normal hearing listened to eight environmental low frequency noises and evaluated the annoyance of the noises. The noises were stationary noise with and without tones, intermittent noise, music, traffic noise and impulsive low frequency noise. The noises were presented twice in a random order at LAeq levels of 20 dB, 27.5 dB and 35 dB. The assessment methods were those used in Sweden, Germany, The Netherlands, Poland and Denmark. It was found that the Danish assessment method gave the best relation to the subjective assessments made by the test persons. An important property of this method is that it includes a 5 dB penalty for noises having an impulsive character.
A Generic Model for Evaluating the Performance of Base-Isolated Buildings
Authors: Talbot J.P. , Hunt H.E.M. 
Published: April 2004

Ground-borne vibration has existed ever since the development of urban road and rail networks. Vibration generated by the moving traffic propagates through the ground and into buildings, resulting in unacceptable levels of internal noise and vibration. A common solution to this increasingly significant problem is the base-isolation of buildings by incorporating vibration isolation bearings between the buildings and their foundations. This technique has been employed for over forty years but the exact performance of base isolation remains uncertain. This paper describes a generic computational model; generic in that it accounts for the essential dynamic behaviour of a typical base-isolated building in order to make predictions of isolation performance. The model is a linear one, formulated in the frequency domain, and consists of a two-dimensional portal-frame model of a building coupled to a three-dimensional boundary-element model of a piled-foundation. Both components of the model achieve computational efficiency by assuming they are infinitely long and using periodic structure theory. Following an overview of the model, a virtual case study is presented to illustrate its practical application. Along with some initial observations, the case of a point-load surface excitation of the foundation is used to investigate the isolation performance of typical isolation bearings.
External thought—does sketching assist problem analysis?
Authors: Sachse Pierre , Hacker Winfried , Leinert Sven 
Published: April 2004

AbstractAn experimental study (n = 60 students) tests the advantages of being allowed to sketch a representation of a mechanical system (involving components such as weights, ropes and pulleys) when one is to be subsequently asked questions about this system. In comparison to a control group who were not allowed to sketch the system, the main advantages of sketching were found to be a reduction in the perceived difficulty of the problems and an increase in the likelihood of correctly inferring relations between the components. These advantages came at no extra cost in terms of additional time being needed to analyse the situation or solve the problems. However, sketching conferred no advantage in terms of the correct recall of system components. Copyright © 2004 John Wiley & Sons, Ltd.
Quantum‐Chemical Studies on the Geometric and Electronic Structures of Bertholloide Cobalt Oxynitrides
Authors: Lumey M.‐W. , Dronskowski R. 
Published: April 2004

AbstractWe report electronic structure calculations using density‐functional theory (local density approximation (LDA) and generalized gradient approximation (GGA); plane waves and muffin‐tin orbitals; pseudopotentials and all‐electron approaches) on non‐stoichiometric CoNxO1–x oxynitride phases. The preference of the experimentally suggested zinc‐blende structure type over the rock‐salt type is confirmed and explained, on the basis of COHP (crystal orbital Hamilton population) chemical bonding analyses, by reduced Co–Co antibonding interactions in the ZnS structural alternative. A pressure‐induced phase transition into the NaCl type, however, is predicted at approximately 30 GPa. Supercell calculations touching upon the exact composition and local structure of CoNxO1–x provide evidence for a broad range of energetically metastable compositions with respect to the zinc‐blende‐type boundary phases CoN and CoO, especially for the more oxygen‐rich phases. All non‐stoichiometric compounds are predicted to be metallic materials which do not exhibit significant magnetic moments. Likewise, there is no indication for anionic ordering such that random anion arrangements are preferred.
The Regioisomeric Triphenylaminoethanols –Comparison of their Efficiency in Enantioselective Catalysis
Authors: Braun Manfred , Fleischer Ralf , Mai Brigitte , Schneider Marc‐André , Lachenicht Stefan 
Published: April 2004

AbstractBoth enantiomers of the novel amino alcohol (R)‐ and (S)‐2 are prepared from the corresponding enantiomer of the mandelic acid‐derived ethanediol 3. The regioisomeric amino alcohols 1 and 2 are converted into the imines 7 and 8, respectively. Titanium complexes 9 and 10 derived therefrom are used as catalysts for the addition of diethylzinc to benzaldehyde and yield the alcohol 11 in up to 92% ee. On the other hand, the chloro‐substituted titanium complexes 14 and 15 are able to mediate the Torgov cyclization reaction of the diketone 16 to give the estrone derivative 17. In both reactions titanium complexes 10 and 15 derived of the novel amino alcohol 2 give higher enantioselectivities than the complexes 9 and 14 that are based on the regioisomeric amino alcohol 1.
High‐Pressure 31P{1H} NMR Studies of RhH(CO)(TPPTS)3 in the Presence of Methylated Cyclodextrins: New Light on Rhodium‐Catalyzed Hydroformylation Reaction Assisted by Cyclodextrins
Authors: Monflier E. , Bricout H. , Hapiot F. , Tilloy S. , Aghmiz A. , Masdeu‐Bultó A. M. 
Published: April 2004

AbstractThe effect of methylated cyclodextrins on the RhH(CO)(TPPTS)3 complex in hydroformylation conditions [50 atm of CO/H2 (1/1) and 80 °C] has been investigated by high‐pressure 31P{1H} NMR spectroscopy. In the presence of methylated β‐cyclodextrin, the equilibria between the rhodium species lie in favor of phosphine low‐coordinated rhodium species. The formation of a stable inclusion complex between this cyclodextrin and the trisulfonated triphenylphosphine ligand (TPPTS) was found to be the key to understanding the displacement of the equilibria. Indeed, the methylated α‐cyclodextrin which does not interact with the TPPTS and the methylated γ‐cyclodextrin which can weakly bind to the TPPTS have no and a very low effect on the equilibria, respectively. These results explain for the first time why a decrease in the normal to branched aldehydes ratio is always observed when cyclodextrins are used as mass‐transfer agents in aqueous biphasic hydroformylation processes.
Preparation of the Novel Mesoporous Solid Acid Catalyst UDCaT‐4 via Synergism of Persulfated Alumina and Zirconia into Hexagonal Mesoporous Silica for Alkylation Reactions
Authors: Yadav Ganapati D. , Murkute Ambareesh D. 
Published: April 2004

AbstractA novel mesoporous solid acid catalyst named UDCaT‐4 was designed by loading persulfated alumina and zirconia (PAZ) into highly oredered, hexagonal mesoporous silica (HMS). UDCaT‐4 was characterized by XRD, BET surface area and pore size analysis which revealed that neither pore blocking nor structure collapse of HMS had occurred. NH3‐TPD and FTIR were used to determine the acid strength and nature of the sulfate ion retained on the surface of UDCaT‐4. It is known that HCl and water have detrimental effects on the activity of the zirconia‐based catalyst. Hence, the activity of UDCaT‐4 was evaluated in comparsion with that of bulk PAZ in the liquid‐phase alkylation of toluene with benzyl chloride and also in the vapour‐phase alkylation of mesitylene with isopropanol, where acid and water are generated in‐situ, respectively, as co‐products. The superior catalytic acivity of UDCaT‐4 is atributed to the uniform dispersion of the superacidic centers of PAZ into HMS vis‐à‐vis bulk PAZ. Reusability and time on‐stream studies reveal that UDCaT‐4 is a robust and reusable catalyst even in the presence of HCl and H2O.
Efficient Biocatalytic Synthesis of Highly Enantiopure α‐Alkylated Arylglycines and Amides
Authors: Wang Mei‐Xiang , Lin Shuan‐Jun , Liu Jun , Zheng Qi‐Yu 
Published: April 2004

AbstractA number of racemic α‐alkylarylglycine amides including 1‐amino‐1‐carbamoyl‐1,2,3,4‐tetrahydronaphthalene underwent efficient biocatalytic hydrolysis under very mild conditions to afford the corresponding (S)‐α‐alkylarylglycines and (R)‐α‐alkylarylglycine amides in excellent yields with enantiomeric excesses higher than 99.5%. Both the reaction rate and enantioselectivity of biocatalytic kinetic resolution were strongly dependent upon the nature of the substituent and the substitution pattern on the benzene ring of the substrate. In contrast, no effective biotransformation of the Strecker nitrile derived from acetophenone was observed under the catalysis of a nitrile hydratase/amidase‐containing microbial Rhodococcus sp. AJ270 whole‐cell catalyst. Coupled with the chemical hydrolysis of amide, this biotransformation process provided efficient syntheses of α‐substituted arylglycines in both enantiomeric forms from readily available racemic amides.
Optimal bimodal pore networks for heterogeneous catalysis
Authors: Gheorghiu Stefan , Coppens Marc‐Olivier 
Published: April 2004

AbstractA practical problem in the rational design of a heterogeneous catalyst is to optimize its structure at all scales. By optimizing the large‐pore network of a bimodal porous catalyst with a given nanoporosity (for example, zeolite or mesoporous catalyst) for the yield of diffusion‐limited first‐order reactions, it is found that catalysts typically benefit from a hierarchical pore network with a broad pore‐size distribution. When comparing the performance of the optimal structures to that of self‐similar, fractal‐like pore hierarchies, it is found that the latter can be made to have the same effectiveness factor as the optimal ones, suggesting that fractal‐like catalysts operate very near optimality, even if their structure is considerably different from that of the true optima. This is useful, because fractal‐like structures have the advantage of being organized in a modular, natural way, potentially easy to reproduce by templating. © 2004 American Institute of Chemical Engineers AIChE J, 50: 812–820, 2004