bluuebunny/crossref_metadata_2025_split huggingface dataset:
Acoustic communication in noise: regulation of call characteristics in a New World monkey
Authors: Brumm Henrik , Voss Katrin , Köllmer Ireen , Todt Dietmar 
Published: December 2003

SUMMARY
This study on common marmosets Callithrix jacchus is the first to examine noise-dependent mechanisms of vocal plasticity in a New World monkey. Since acoustic communication can be considerably impaired by environmental noise, some animals have evolved adaptations to counteract its masking effects. The studied marmosets increased the sound level of their spontaneous calls in response to increased levels of white noise broadcast to them. Possibly, such noise-dependent adjustment of vocal amplitude serves to maintain a specific signal-to-noise ratio that is favourable for signal production. Concurrently, the adjustment of vocal amplitude can maintain a given active space for communication. In contrast to some bird species, no noise-induced increase in the number of syllables per call series could be found, showing that an increased serial redundancy of vocal signals was not used to communicate under noisy conditions. Finally, we examined a possible noise-dependent prolongation of vocal signals. This approach was guided by the findings of perceptional studies, which suggest an increased detection probability of prolonged signals in noise by temporal summation. Marmosets indeed increased the duration of their call syllables along with increasing background noise levels. This is the first evidence of such mechanism of vocal plasticity in an animal communication system.
Kinematics of the transition between aquatic and terrestrial locomotion in the newtTaricha torosa
Authors: Ashley-Ross Miriam A. , Bechtel Brett F. 
Published: December 2003

SUMMARYCalifornia newts (Taricha torosa) are capable of locomotion in both aquatic and terrestrial environments. The transition between swimming and terrestrial walking was examined by videotaping individual Tarichawalking both up and down a ramp, inclined at 15° to the horizontal, that had its lower end immersed in water and its upper end out of the water. When ascending the ramp, California newts first approached it by swimming, then used their limbs to walk while still in water, and finally left the water using a normal terrestrial walking gait. The reverse of this sequence was observed when individuals descended the ramp. In both directions, Taricha used a lateral sequence walk with a duty factor of approximately 76% when out of the water. Timing of footfalls was more variable in water and featured shorter duty factors, leading to periods of suspension. Comparison of angular and timing variables revealed effects due to direction and degree of immersion. Few timing variables showed differences according to stride within sequence (indicating whether the animal was in or out of the water), suggesting that the basic walking pattern is equally good in both environments.
The binding and recall of snapshot memories in wood ants (Formica rufaL.)
Authors: Graham Paul , Durier Virginie , Collett Thomas S. 
Published: December 2003

SUMMARYInsects can locate spatial goals by means of 2-D retinotopic views of the surrounding landmarks, which they memorise from the vantage point of the goal. Wood ants acquire such snapshot memories while fixating conspicuous landmarks with frontal retina, and their snapshots extend horizontally at least 120°into the periphery. Are spatially separate items within such an extended snapshot bound together so that a snapshot is recalled as a whole, or are its components recognised individually?We approached this question by training ants to find food midway between two upright black cylinders of different sizes and then examined where they searched when they were given two cylinders of the same size. If the ants know which cylinder replaces the small cylinder and which the large, they should search at a position where the two equal-sized cylinders subtend the same angles as do the training cylinders when viewed from the feeder. Ants conformed to this prediction under one condition, searching at a shorter distance from the substitute for the large cylinder than from the substitute for the small cylinder. But, under another condition, ants were unable to distinguish between the two equal-sized cylinders. Ants failed when white curtains completely surrounded the platform on which the cylinders were placed. They succeeded when one side of the platform had a patterned curtain.We suggest that ants take two snapshots at the feeding site, one when facing the small cylinder and one when facing the large cylinder, and that each snapshot includes the patterned curtain, if it is there. Ants will view the patterned curtain with the lateral retina of one eye when facing the small cylinder and with the lateral retina of the other eye when facing the large cylinder. Our data suggest that there may be associative links between these spatially separate components of the snapshot, which cause the memory of the small cylinder or the large cylinder to be recalled according to which eye sees the curtain. It seems that an extended snapshot not only enhances the accuracy of localisation but can also increase the reliability of snapshot recall, provided that the components of a snapshot are bound together.
The tale of the tail: limb function and locomotor mechanics inAlligator mississippiensis
Authors: Willey Jeffrey S. , Biknevicius Audrone R. , Reilly Stephen M. , Earls Kathleen D. 
Published: December 2003

SUMMARYCrocodilians tow their large muscular tail behind them during terrestrial bouts when they high walk (a walking trot). Analysis of ground reaction forces in the American alligator (Alligator mississippiensis) revealed the consequences of tail-dragging. Individual limb and tail ground reaction force records show that the hindlimbs of Alligator take on a substantial role in body mass support consistent with the more caudal location of its center of mass due to the presence of a particularly heavy tail (representing nearly 28% of total body mass). Furthermore, because the constant drag imposed by the tail is substantial, both fore- and hindlimbs in Alligatorhave a heightened propulsive role as a means of countering the net braking effect of the tail. Ground reaction forces of the whole body were used to assess how well Alligator was able to utilize mechanical energy-saving mechanisms (inverse pendulum or mass-spring). A high-walking Alligator recovers, on average, about 20% of its mechanical energy by inverse pendulum mechanics. These modest energy recovery levels are likely to be due to a combination of factors that may include low locomotor speed,imprecise coordination of contralateral limbs in the trot, frequent dragging of feet of protracting limbs during swing phase and, possibly, tail dragging.
Inhibition of the increased 17β-estradiol-induced mast cell number by melatonin in the testis of the frog Rana esculenta, in vivo and in vitro
Authors: Izzo Gaia , d'Istria Michela , Serino Ismene , Minucci Sergio 
Published: December 2003

SUMMARY
In the present study, we have utilized 17β-estradiol to induce the increase of mast cell number in order to verify the melatonin effect on mast cell accumulation in the frog testicular interstitium. Data obtained from in vivo experiments confirm that 17β-estradiol increases the mast cell number and indicate a melatonin-inhibitory role in their accumulation in the frog testis. In addition, melatonin interferes with the effects of estradiol on the increase of mast cell number in short-term cultured testes, and this result has also been obtained in a dose-response experiment at physiological concentration. The data suggest that melatonin acts on mast cell number directly via its local action in the frog gonads. In conclusion, our study shows, for the first time, that melatonin may interfere, probably via estrogen receptors, with the differentiation and/or proliferation of mast cells induced by estradiol treatment either in vivo or in vitro in the testis of the frog Rana esculenta.
Effect of aestivation on long bone mechanical properties in the green-striped burrowing frog,Cyclorana alboguttata
Authors: Hudson Nicholas J. , Bennett Michael B. , Franklin Craig E. 
Published: December 2003

SUMMARYThe green-striped burrowing frog, Cyclorana alboguttata, survives extended drought periods by burrowing underground and aestivating. These frogs remain immobile within cocoons of shed skin and mucus during aestivation and emerge from their burrows upon heavy rains to feed and reproduce. Extended periods of immobilisation in mammals typically result in bone remodelling and a decrease in bone strength. We examined the effect of aestivation and, hence,prolonged immobilisation on cross-sectional area, histology and bending strength in the femur and tibiofibula of C. alboguttata. Frogs were aestivated in soil for three and nine months and were compared with control animals that remained active, were fed and had a continual supply of water. Compared with the controls, long bone size, anatomy and bending strength remained unchanged, indicating an absence of disuse osteoporosis. This preservation of bone tissue properties enables C. alboguttata to compress the active portions of their life history into unpredictable windows of opportunity, whenever heavy rains occur.
Stereoselective Hydrolysis of p-Nitrophenyl Glycoside by Boronic Acid
Authors: Ohe Takeru , Kida Toshiyuki , Zhang Wanbin , Nakatsuji Yohji , Ikeda Isao 
Published: December 2003

Abstract
The alkaline hydrolysis of p-nitrophenyl α-D-glucoside, α-D-galactoside, and β-D-mannoside was selectively accelerated by addition of methyl boronic acid, as compared to that of the corresponding β-D-glucoside, β-D-galactoside, and α-D-mannoside. In the case of p-nitrophenyl α (or β)-D-glucoside, the α/β selectivity was increased up to 110 when four molar equivalents of methyl- or phenylboronic acid were added.
Hydrolysis of Acetyl-methionine-containing Dipeptides Promoted by Palladium(II) Complexes Containing Methionine-amino Acids as Ligands
Authors: Luo Xuemei , Chen Xiaohua , Song Yongcheng , Zhu Longgen 
Published: December 2003

Abstract
The [Pd(N,S-Met-a′a′H)(N,S-AcMet-aaH)]+(a′a′H and aaH = amino acids) was characterized by electrospray ionization mass spectrometer(ESI-MS) and 1H NMR, in which Met-a′a′H, as ligand, coordinates to Pd(II) via thioether and terminal amino group, and AcMet-aaH, as substrate, coordinates to Pd(II) via thioether and deprotonated amide nitrogen of methionine. The Met-a′a′ bond in ligand is intact, the Met-aa bond in substrate, however, is activated toward hydrolysis. The difference in hydrolysis behavior between ligand and substrate may be due to a fused six-membered and five-membered ring formation via thioether, deprotonated amide nitrogen and carbonyl oxygen of methionine residue in substrate.
Novel Synthesis of 5-Phenyliodonium Triflate Substituted Uracil Nucleosides
Authors: Roh Kyoung Rok , Kim Joong Young , Kim Yong Hae 
Published: December 2003

Abstract
5-Phenyliodonium triflate substituted uracil nucleosides have been prepared by one step reaction of uracil nucleosides with (diacetoxyiodo)benzene-trifluoromethanesulfonic acid.
Molecular Recognition by Novel Macrotetracyclic Cyclophanes Having Dipeptide Segments
Authors: Tanaka Akinori , Shimada Shintaro , Hirohashi Tomoko , Hayashi Takashi , Hisaeda Yoshio 
Published: December 2003

Abstract
Novel macrotetracyclic cyclophanes, which are constructed with four cyclophane units having eight dipeptide moieties, have been prepared and characterized by various spectroscopic methods. The guest-binding behavior of the host toward water-soluble porphyrines was examined by electronic spectroscopy.
T-Site Selective Photocleavage of DNA by Cationic Schiff Base Complex of Manganese(III)
Authors: Sakamoto Fuminori , Sumiya Tomoyuki , Fujita Masaaki , Tada Toshiji , Tan Xiang Shi , Suzuki Eiji , Okura Ichiro , Fujii Yuki 
Published: December 2003

Abstract
Manganese(III)-Schiff base complexes of cationic salen and salph derivatives were newly prepared and their molecular structures were determined by X-ray crystal structure analysis. The cationic salph complex effectively cleaved T-site of DNA in ca. 88% selectivity upon visible light irradiation.
STM Observation of Chiral 1,2-Dihydroxyoctadecane Monolayer Self-assembled on the Graphite Surface
Authors: Qian Pu , Nanjo Hiroshi , Yokoyama Toshiro , Suzuki Toshishige M 
Published: December 2003

Abstract
Chiral 1,2-dihydroxyoctadecane (C16H33CH(OH)CH2OH) self-assembled on graphite surface was observed by STM and the molecular patterns obtained were interpreted by homochiral association of constituent molecules at hydroxyl groups.
Synthesis of Heterodiquinanes by Photoreaction of β-Keto Esters with Oxime Methyl Ethers Derived from 3-Acyl-1,2-dihydrocinnoline-1,2-dicarboximides
Authors: Tanaka Satoko , Seguchi Kazuyoshi 
Published: December 2003

Abstract
Photoreaction of hydrazodicarboximide with β-keto esters in acetonitrile in the presence and absence of triethylamine afforded intriguing heterodiquinane-based tricycles in moderate yields, together with both rearranged and dimeric products.
Time-resolved UV-Vis Spectroelectrochemical Studies of the Conformational Rearrangement in the Electron Transfer of Cytochrome c
Authors: Wu Ling-Ling , Huang Huai-Guo , Li Jing-Xin , Luo Jin , Lin Zhong-Hua 
Published: December 2003

Abstract
The present work used mainly electrochemical in situ time-resolved UV-Vis subtractive reflectance spectroscopy to study the electron transfer process of cytochrome c in the presence of promoter(the equal molal mixture of guanine and cytosine). Three new absorption bands, 420 nm, 450 nm and 500 nm, are observed in the spectra with different time resolutions, as well as two bipolar absorption bands 250 nm and 300 nm. All the results show that the electron transfer of cytochrome c is accompanied by significant conformational rearrangement.
Novel Cage Polycarbosilanes. Preparation and Characterization of Dodecamethyl-2,3,5,6,7,8-hexasilabicyclo[2.2.2]octane and Its Derivatives
Authors: Shimizu Masaki , Inamasu Naoko , Nishihara Yasushi , Hiyama Tamejiro 
Published: December 2003

Abstract
2,2,3,3,5,5,6,6,7,7,8,8-Dodecamethyl-2,3,5,6,7,8-hexasilabicyclo[2.2.2]octane (1) was synthesized for the first time via three steps in 56% overall yield through triple silylation with three dichlorodimethyldisilane molecules of two trianionic molecules derived from bis(phenylthio)methane. The molecular structure of 1 was shown to be slightly distorted from an ideal bicyclo[2.2.2]octane skeleton by X-ray analysis. The derivatization of 1 and UV spectra of those compounds are described.
Synthesis of α-Methoxy-α,β-unsaturated Esters by Iodine-oxidation of the Anions of Fischer-type Carbene Complexes
Authors: Iwasawa Nobuharu , Fuchibe Kohei 
Published: December 2003

Abstract
α-Methoxy vinyl tungsten species, generated by the deprotonation reaction of Fischer-type carbene complexes or by the Michael addition of lithium enolates to α,β-unsaturated carbene complexes, were found to give α-methoxy-α,β-unsaturated esters in good yields by iodine-oxidation in the presence of silver triflate.
Syntheses, Structures, and Insulin-like Activities of Oxovanadium(IV) Complexes with Tetra- and Penta-dentate Histidine Derivatives
Authors: Kawabe Kenji , Suekuni Tomonari , Inada Takanori , Yamato Kazuhiro , Tadokoro Makoto , Kojima Yoshitane , Fujisawa Yae , Sakurai Hiromu 
Published: December 2003

Abstract
[VO(pmH)(ClO4)], [VO(HeY)], and [VO((pm)2H)](ClO4) were prepared by reactions of VOSO4 and pmH (N-2-pyridylmethyl-(S)-histidine), HeY (N,N′-ethylene-(S)-histidine-(S)-tyrosine), and (pm)2H (N,N-bis(2-pyridylmethyl)-(S)-histidine), respectively, and followed with Ba(ClO4)2. X-ray structure analysis of [VO(HeY)] showed that a pentadentate ligand and an oxoanion were coordinated with a vanadium(IV) ion, thereby forming a distorted octahedral geometry. In in vitro evaluation using isolated rat adipocytes, a tetradentate complex [VO(pmH)(ClO4)](IC50 = 0.762 mM) was found to be more active at lower concentration than VOSO4 (IC50 = 3.56 mM) in term of IC50 value, a 50% inhibition concentration of FFA release from the adipocytes. On the other hand, two VO complexes of pentadentate (HeY and (pm)2H) ligands were found to be inactive for insulin-like activities.
Investigations of the Thermal Inversion Rates of Azobenzenes in Supercritical and Gaseous CO2: A Shift from the Energy-Transfer-Limited to the TST-Valid Region at Low Densities
Authors: Usui Toshinori , Funahashi Shigenobu , Takagi Hideo D , Asano Tsutomu 
Published: December 2003

Abstract
Studies of slow thermal Z/E isomerization reactions around the N=N double bond of azobenzenes in supercritical and gaseous carbon dioxide revealed that a shift from the energy-transfer-limited to the TST-valid region predicted by Kramers takes place at relatively low densities.
Quantitative Separation of Alkaline Earth Metal Ions by Triple-phase Separation Method
Authors: Komatsu Yu , Umetani Shigeo , Tsurubou Shigekazu , Michiue Yuichi , Sasaki Takayoshi 
Published: December 2003

Abstract
The triple-phase separation system has been designed for the first time combining the solvent-extraction and the ion-exchange methods. Owing to the reverse selectivity tendency of the solvent extraction and the ion exchange methods for alkaline earth metal ions (Mg2+, Ca2+, Sr2+ and Ba2+), the quantitative separation could be achieved by the triple-phase separation method.
A Facile Synthesis and Electro-optical Properties of New Liquid Crystals Having a vic-Difluoro Olefinic Moiety
Authors: Kanie Kiyoshi , Tanaka Yoichiro , Takehara Sadao , Hiyama Tamejiro 
Published: December 2003

Abstract
A facile method for the difluorination of olefins was exploited and applied to the synthesis of novel liquid crystals (LCs) having a vic-difluoro olefinic moiety. The physical and electro-optical properties of these LCs were compared with those of the corresponding parent olefinic LCs.
Bioaffinity Sensor to Anti-DNA Antibodies Using DNA Modified Au Electrode
Authors: Katayama Yoshiki , Nakayama Masamichi , Irie Hiroshi , Nakano Koji , Maeda Mizuo 
Published: December 2003

Abstract
Calf thymus DNA was modified on Au electrode as chemoreceptive ligand. This sensor responded selectively to anti-DNA antibody which recognizes DNA molecule. This sensing system is potentially worthy for the development of biosensor of DNA binding proteins.
Proton Conductive Silica Gels Doped with Several Acids and Their Application to Electric Double-Layer Capacitor
Authors: Matsuda Atsunori , Honjo Hiroshi , Tatsumisago Masahiro , Minami Tsutomu 
Published: December 2003

Abstract
Polyvinyl alcohol-containing silica gels doped with HClO4, H2SO4, or H3PO4 prepared by the sol-gel method exhibited high proton conductivities of 10−5-10−2S cm−1 at room temperature. Totally solid state electric double-layer capacitors fabricated using the gels as an electrolyte and activated carbon powder, ACP, as a polarizable electrode showed large capacitances of 31-44F/(gram of total ACP), which were comparable to those of the capacitors with liquid electrolytes.
Molecular Imprinting of Protected Amino Acids in Ultrathin Multilayers of TiO2 Gel
Authors: Lee Seung-Woo , Ichinose Izumi , Kunitake Toyoki 
Published: December 2003

Abstract
A complex of carbobenzyloxy-L-alanine and titanium n-butoxide was adsorbed to hydroxylated surfaces repeatedly to produce ultathin multilayers, which, upon removal of the amino acid template, showed selective binding of carbobenzyloxy-L-amino acids.
Chemical Species Active for Selective Oxygenation of Methane with Hydrogen Peroxide Catalyzed by Vanadium-containing Compounds
Authors: Seki Yasuhiro , Mizuno Noritaka , Misono Makoto 
Published: December 2003

Abstract
UV-vis data revealed that monoperoxomonovanadate is an active species for liquid-phase oxygenation of methane with hydrogen peroxide catalyzed vanadium-containing catalysts in trifluoroacetic anhydride.
Self-assembled Monolayers of Dendron-thiol on Solid Substrate
Authors: Bo Zhishan , Zhang Li , Zhao Bing , Zhang Xi , Shen Jiacong , Höppener Stephanie , Chi Lifeng , Fuchs Harald 
Published: December 2003

Abstract
A polyther dendron with a thiol group at the focal point was synthesized and well characterized, and then used for the preparation of self-assembly monolayers (SAMs) on metal surface. The monolayers on metal surface were studied by Fourier transform surface enhanced Raman scattering spectroscopy(FT-SERS) and STM etc.
The Half-sandwich Hydride and 16-Electron Complexes of Rhodium and Iridium Containing (1S,2S)-N-(p-Toluenesulfonyl)-1,2-diphenylethylenediamine: Relevant to the Asymmetric Transfer Hydrogenation
Authors: Mashima Kazushi , Abe Tomoyuki , Tani Kazuhide 
Published: December 2003

Abstract
We prepared the half-sandwich hydride and 16-electron complexes of rhodium and iridium bearing an anion of (1S,2S)-N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine: for the iridium catalyst system, a 16-electron complex 2b and an 18-electron, hydride complex 3b were synthesized, while only a 16-electron complex 2a was detected for the rhodium catalyst.
Simple and Convenient Method for the Synthesis of Δ9(11)-3-Hydroxy, Δ1,4- and Δ1,4,9(11)-3-Ketosteroids by Selective Dehydrogenation of 3-Hydroxy-12-Ketosteroids
Authors: Kongkathip Boonsong , Kongkathip Ngampong , Khunnavutimanotum Ponsak , Sakee Uthai 
Published: December 2003

Abstract
Hecogenin can be selectively dehydrogenated to the corresponding Δ9(11)-3-hydroxysteroid, Δ1,4- and Δ1,4,9(11)-3-ketosteroids by the treatment of 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) with a variety of solvents.
Efficient Construction of A,B-Rings Component for Syntheses of Phycocyanobilin and Its Derivative
Authors: Jayasundera Krishanthi Padmarani , Kinoshita Hideki , Inomata Katsuhiko 
Published: December 2003

Abstract
Total syntheses of phycocyanobilin and its photoactivatable derivative were accomplished by developing a new and versatile method for the construction of A,B-rings component, which consists of the Wittig-type new coupling reaction of 4-(1-methoxyethyl)-3-methyl-5-tosyl-1,5-dihydro-2H-pyrrol-2-one and a 2-formyl pyrrole derivative in the presence of nBu3P and a base, followed by reduction with aluminum amalgam and subsequent acid treatment.
Lipase-Catalyzed Transesterification of trans-2,5-Disubstituted Pyrrolidines: Effect of Substituent on Enantioselectivity
Authors: Kawanami Yasuhiro , Iizuna Noriko , Okano Kiyoka 
Published: December 2003

Abstract
Kinetic resolution of racemic N-arylmethylated trans-2-acetoxy-methyl-5-hydroxymethylpyrrolidines by using lipasecatalyzed transesterification has been studied. The enantioselectivity depends significantly on the structure of the aryl ring and N-3,5-dimethylbenzylpyrrolidine was found to be the best substrate for the present reaction.
Multilayer Organic Electroluminescent Device with Dithienosilole Derivative
Authors: Adachi Akira , Ohshita Joji , Kunai Atsutaka , Kido Junji , Okita Koichi 
Published: December 2003

Abstract
Dithienosilole derivatives (DTS) improved an electron injection efficiency of the typical organic electroluminescent device, indicating that DTS may have a high electron affinity.DTS also exibited a blue light emitting and hole injection properties.
Extremely High Pseudo-Capacitance of RuO2 Highly Dispersed on Glassy Carbon
Authors: Takasu Yoshio , Matsuo Chiemi , Ohnuma Takeshi , Ueno Mitsuo , Murakami Yasushi 
Published: December 2003

Abstract
By means of a model electrode method, it has been found that the ruthenium oxide highly dispersed on glassy carbon produces an extremely large surface charge density which corresponds to more than one proton adsorbs on every ruthenium loaded on the glassy carbon, if the charge was supposed to be caused only by the adsorption of proton on the RuO2.