bluuebunny/crossref_metadata_2025_split huggingface dataset:
Susceptibility of frog (Rana temporaria) and toad (Bufo bufo) eggs to invasion by Saprolegnia
Authors: Griffiths Richard , Robinson Jim , Jeffries Peter 
Published: October 2003

AbstractInfections of amphibian eggs sometimes cause catastrophic losses of reproductive effort, but susceptibility to infection in different species is poorly understood. Using laboratory trials we showed that direct hyphal invasion of adjacent eggs by Saprolegnia caused a higher incidence of infection than invasion by zoospores. Moreover, we observed that dead eggs were much more readily colonized than live eggs when challenged with zoospores from two strains of Saprolegnia. The two strains were equally effective in causing infections of Rana temporaria eggs, but differed in their ability to infect eggs of Bufo bufo. In live R. temporaria eggs, early stages (pre-tailbud) were more frequently infected by hyphal invasion than later stages by the same strains, suggesting that susceptibility to infection decreases as development proceeds.
A new species of Elachistocleis (Anura: Microhylidae) from the Andean Yungas of Argentina, with comments on the Elachistocleis ovalis - E. bicolor controversy
Authors: Ferrari Liliana , Vaira Marcos , Lavilla  
Published: October 2003

AbstractElachistocleis skotogaster spec. nov. is described from the Andean Yungas of Argentina. It is unique in the genus in having belly and legs densely spotted with brown, an uniformly dark brown dorsal mottled with black, absence of a light vertebral strip, a fold behind the mouth but not a postcommisural gland. Its natural history and advertisement call are briefly noted. Elachistocleis ovalis and E. bicolor are considered different species, and Buenos Aires, Argentina, is established as type locality for the latter one. Se describe Elachistocleis skotogaster n. sp. de las Yungas andinas de Argentina. Se diferencia de las restantes especies del género por presentar vientre y región inferior de los miembros posteriores densamente punteada de castaño, la región dorsal castaño oscuro, punteada en negro, sin banda vertebral clara, y el área por detrás de la boca con un pliegue pero sin glándula postcomisural. Elachistocleis ovalis y E. bicolor son consideradas especies diferentes y se establece Buenos Aires, Argentina, como localidad tipo de esta última.
A new frog of the genus Mantidactylus from the rainforests of north-eastern Madagascar, and its karyological affinities
Authors: Odierna Gaetano , Vences Miguel , Aprea Gennaro , Andreone Franco 
Published: October 2003

AbstractWe describe a new species of the genus Mantidactylus found during field inventories in the north-eastern rainforests of Madagascar. Mantidactylus salegy sp. n. reaches a snout-vent length of 45-50 mm, has evident dorsolateral ridges and whitish spots on the upper jaws (mainly in females). The vocal sacs in males are distinctly visible and paired subgular, without strongly inflatable areas recognizable between the blackish lateral skin flaps on the throat. This frog exhibits a mosaic of characters previously thought to be typical for either the subgenera Gephyromantis or Phylacomantis. Therefore, it is a crucial discovery towards better understanding of the relationships between the taxa included in these two subgenera, supporting previous molecular results which indicated their paraphyly. The call of M. salegy consists of a rapid series of 8-11 rattling notes emitted at 1000-3500 Hz. We also provide karyological data for M. salegy, and for several related species, M. granulatus, M. leucomaculatus, M. moseri, M. redimitus, M. zavona, and M. pseudoasper (attributed to the subgenus Phylacomantis) and M. luteus (subgenus Gephyromantis). In terms of general chromosome morphology and structure, NOR localisation and heterochromatin characteristics, M. salegy shows similarities to M. redimitus, M. zavona and M. leucomaculatus, all included within Phylacomantis. Our data confirm that NOR position is a phylogenetically informative character.
Two new species of the Boophis mandraka complex (Anura, Mantellidae) from the Andasibe region in eastern Madagascar
Authors: Glaw Frank , Vences Miguel , Vallan Denis 
Published: October 2003

AbstractThe treefrog genus Boophis is represented in Madagascar by 50 described species. In this paper we describe two new cryptic species: B. liami sp. nov. and B. solomaso sp. nov. are similar to B. mandraka in morphology and colouration, but are clearly different in bioacoustic and genetic characters. The existence of many sibling species within Boophis shows the importance of detailed studies to clarify the distribution and the ecological requirements of the species in this genus. Les anoures arboricoles du genre Boophis sont représentés à Madagascar par 50 espèces. Dans cet article nous décrivons deux nouvelles espèces cryptiques : B. liami sp. nov. et B. solomaso sp. nov. ressemblent a B. mandraka par la coloration et la morphologie, mais ce distinguent clairement par la bioacoustique et le caractères génétiques. L'existence de beaucoup de "sibling species" dans le genre Boophis montre l'importance des études détailles pour qu'on puisse clarifier les questions concernant la répartition et les demandes écologiques des espèces de ce genre.
Phylogeography of the genus Xenopus in southern Africa
Authors: Channing  , Measey  
Published: October 2003

AbstractXenopus laevis (Daudin, 1802) has been the subject of numerous studies but is taxonomically poorly understood. Part of the Cytochrome b gene in mitochondrial DNA was sequenced from 50 individual Xenopus from three currently recognised species, taken from 28 localities in southern Africa, and from an outgroup of two West African X. epitropicalis. Phylogenetic analyses of these data reveal well-supported tree structure, demonstrating three clades within what is currently regarded as X. laevis : X. l. laevis from the Cape, X. l. petersii, and X. l. laevis from further north. This evidence agrees with other studies (on morphology, call and parasite data) which suggest that what is currently regarded as X. laevis encompasses more than one species. Workers using Xenopus collected away from the Cape of South Africa are not safe in assuming that they are using X. laevis.
Digestive ecology of two omnivorous Canarian lizard species (Gallotia, Lacertidae)
Authors: Valido Alfredo , Nogales Manuel 
Published: October 2003

AbstractOmnivorous endemic Canarian lacertids (Gallotia atlantica and G. galloti) do not present any specific digestive and physiological adaptations to herbivorous diet, compared to species and populations with a different degree of herbivory in the Canarian archipelago. The only characteristics that could be related to the type of diet were the number of cusps per tooth (between species) and the number of small stones contained in droppings (between species and populations). The rest of measured traits were correlated with lizard size and for this reason G. galloti has longer intestines, heavier stomachs and livers, more teeth and cusps, and longer gut passage. These data suggest that body size is a major determinant of the reliance on plant food (mainly fleshy fruits) in these lizards and facilitates mutualistic interactions with fleshy-fruited plant species.
Aggregation behaviour and movement patterns in the large-scaled girdled lizard, Cordylus macropholis
Authors: Mouton P. Le Fras , Nieuwoudt Cara , Flemming Alexander 
Published: October 2003

AbstractAggregation behaviour and movement patterns were studied in the large-scaled girdled lizard, Cordylus macropholis. The size of aggregations within Euphorbia caput-medusae plants ranged from one to 14 individuals. Aggregation was a year-round phenomenon and aggregations were generally larger during autumn/winter than during spring/summer. Most aggregations consisted of an adult pair together with a varying number of juveniles. Site fidelity was low, with females showing significantly higher site fidelity than males. Movement of individuals in and out of the marked population was high, with no sex differences. Females covered slightly greater distances than males outside the mating season, whereas males covered slightly greater distances than females within the mating season. The results suggest that aggregation behaviour and high degree of movement in C. macropholis are the result of competition for a limited plant resource. The results do not confirm differential movement patterns between the sexes.
Geographic variability and taxonomy of the nose-horned viper, Vipera ammodytes (L. 1758), in the central and eastern parts of the Balkans: A multivariate study
Authors: Džukić Georg , Tomović Ljiljana 
Published: October 2003

AbstractA multivariate analyses of various morphological characters (morphometric, meristic and qualitative) of nose-horned viper (Vipera ammodytes) revealed a complex morphological differentiation of populations from the central and the eastern Balkan Peninsula. Analyses of quantitative data showed no clear morphological discrimination or well-defined taxonomical units. On the contrary, analyses of qualitative traits separated two discrete taxa in the analysed area. One, inhabiting the eastern and the southern part of the Balkans, includes samples from most parts of Bulgaria, Former Yugoslav Republic of Macedonia and south-eastern Serbia, whereas the other ranges from north-western Bulgaria through the main part of Serbia (except the south-east) to Montenegro.
Torque loss in spur gears with interference
Authors: Spiegelberg C , Christie M 
Published: October 2003

Gears with interference (zero backlash) are used in robots and other precision equipment. The reason for using interference gearing is to improve positioning and motion control. It is then also desirable to compensate for the friction losses and therefore it is important to model the friction losses accurately. In this paper, results from a model for simulating spur gears with interference are compared with results from a test rig for spur gears with interference. FZG gears are used both in the test rig and in the simulations. Brief descriptions of the test rig and the simulation model are given in the paper; more thorough descriptions can be found in studies by Hedström and Kårhammar and by Spiegelberg, Andersson and Sellgren respectively. There is also a description of the measurements and the procedure of making them. The aim of this paper is to compare the results from the test rig with the results from the simulation model and to analyse the results from the test rig. The results show that the simulated torque loss corresponds well with the measured torque loss within the range of the test rig. The results from both the test rig and the simulation model show that there are large variations in the frictional torque during one mesh of a gear tooth. The loss increases with the number of contact points and the lowest loss is found when a driving gear flank passes the pitch point. The overall efficiency decreases when the mesh force increases and the lowest efficiency readings are found when a combination of high mesh force and low load is applied.
Versatility of the Titanium(IV)–Porphyrin Reagent for Determining Hydrogen Peroxide
Authors: Takamura Kiyoko , Matsubara Chiyo 
Published: October 2003

Abstract
Hydrogen peroxide has been an important analyte in many fields for many years. The Ti–TPyP reagent, i.e., an acidic aqueous solution of oxo[5,10,15,20-tetra(4-pyridyl)porphyrinato]titanium(IV) complex, was developed as a highly sensitive spectrophotometric reagent for determining traces of hydrogen peroxide. Following the addition of hydrogen peroxide to the reagent, the absorbance at 432 nm decreased and a new peak appeared at 450 nm (the Soret band) accompanied by the consumption of the complex and the formation of its monoperoxo complex, respectively. The degrees of the absorbance changes were found to be proportional to the hydrogen peroxide concentration with the apparent molar absorptivities of 1.9 × 105 (432 nm) and 1.1 × 105 (450 nm) M−1 cm−1 (1 M = 1 mol dm−3). Both values are much larger than those obtained by the conventional analysis methods. Based on these facts, the determination of hydrogen peroxide was made by a batch method and a flow injection analysis (FIA) method with the detection limits of 25 pmol and 0.5 pmol per test, respectively. In this account, the Ti–TPyP reagent is assessed for determining hydrogen peroxide in rainwater and in the atmosphere, and for determining several components in foods and biofluids mediated by appropriate oxidase enzymes, to demonstrate its potential for a broad range of applications.
PdII-Catalyzed Reaction of Phenols with Propiolic Esters. A Single-Step Synthesis of Coumarins
Authors: Kitamura Tsugio , Yamamoto Kiyomi , Kotani Masashi , Oyamada Juzo , Jia Chengguo , Fujiwara Yuzo 
Published: October 2003

Abstract
The intermolecular reaction of phenols with propiolic esters in TFA in the presence of a Pd(OAc)2 catalyst, affording coumarin derivatives, is described. An exclusive formation of 5,6,7-trimethoxy-4-phenylcoumarin was observed in the reaction of 3,4,5-trimethoxyphenol and ethyl phenylpropiolate with a catalytic amount of Pd(OAc)2. The reaction in the absence of Pd(OAc)2 did not give any coumarin at all. Coumarin derivatives were obtained in high yields in the cases of electron-rich phenols, such as 3,4-methylenedioxyphenol, 3-methoxyphenol, 2-naphthol, and 3,5-dimethoxyphenol. Furthermore, the reaction of some phenols with various 2-alkynoates or with diethyl acetylenedicarboxylate gave the corresponding coumarins in good-to-high yields.
Conformational Analysis of (±)-(1,1′-Biindene)-3,3′-dione, 2,2′,3,3′-Tetrahydro-(1,1′-binaphthalene)-4,4′(1H,1′H)-dione, and (1,1′-Bibenzosuberene)-5,5′-dione
Authors: Lam Yulin , Ma Ngai Ling , Huang Hsing-Hua , Liang Eping 
Published: October 2003

Abstract
The dipole moments of (±)-(1,1′-biindene)-3,3′-dione 1, (±)-2,2′,3,3′-tetrahydro-(1,1′-binaphthalene)-4,4′(1H,1′H)-dione 2, and (±)-(1,1′-bibenzosuberene)-5,5′-dione 3 in carbon tetrachloride and benzene were measured over a range of temperatures. Analyses of the relative permittivity data in carbon tetrachloride and benzene showed that at 25 °C, 1 exists predominantly in the gauche conformation, whilst 2 and 3 favor the trans form. The experimentally derived values of the energy difference between the gauche and trans rotamers and the gauche/trans population quotient were compared with values predicted by molecular-orbital calculations. The crystal and molecular structures of 2 and 3 were determined by single-crystal X-ray diffraction methods. Both compounds exist in the trans conformation in the solid-state. Dynamic 1H NMR was employed to 3 in order to determine the activation parameters for the barriers to rotation in solution.
Electronic Structure of Sulfanenitriles
Authors: Bharatam Prasad V , Amita  , Kumar P Senthil 
Published: October 2003

Abstract
Ab initio calculations have been carried out to analyze the electronic structure of organosulfur compounds with S≡N. The electronic structures of R3S≡N, R(O)S≡N, and RS≡N have been compared. The calculations suggest that the S–N interactions should be taken as a hybrid of the S≡N triple bond and the S+–N− single bond. The balance between the two resonating structures shift towards a S≡N triple-bonded arrangement with an increase in the electronegativity of substituents on sulfur. The strength of the Lewis basicity of sulfanenitriles has been estimated by studying their proton affinities and the complexation energies with BH3. On the potential energy surface of H3S≡N, this hypervalent compound has been shown to be a high-energy local minimum; although its 1,2-H shift isomers are all more stable, the barrier for the 1,2-shift is very high.
Decomposition of Trichlorobenzene Isomers by Co-Grinding with CaO
Authors: Tanaka Yasumitsu , Zhang Qiwu , Mizukami Koichi , Saito Fumio 
Published: October 2003

Abstract
Two types of trichlorobenzene (TCB) isomers, 1,2,3- and 1,3,5-, were subjected to grinding in air with CaO in a planetary ball mill to investigate their decomposition phenomena. Results showed that TCB samples were decomposed by the co-grinding to form calcium chloride hydrate and amorphous carbon as the main products, with other minor compositions such as carbon dioxide and water. There was no significant difference in the decomposition phenomena between the two isomers. Radicals were generated during the decomposition process, predominantly due to the rupture of C–Cl bonds in the molecule. Supported by the simulation data, we concluded that dehydrochlorination during TCB decomposition process to form hydrochloride (HCl, further to CaOHCl) exhibited the lower possibility, suggesting dechlorination rather than dehydrochlorination as the plausible decomposition pathway.
Lowest Electronically Excited Triplet States of 1,2,4,5-Tetracyanobenzene and Tetracyanopyrazine by Matrix-Isolation Infrared Spectroscopy Combined with a Density-Functional-Theory Calculation
Authors: Akai Nobuyuki , Miura Isamu , Kudoh Satoshi , Shigehara Kiyotaka , Nakata Munetaka 
Published: October 2003

Abstract
The infrared spectra of photoexcited transient species produced during UV irradiation from 1,2,4,5-tetracyanobenzene (TCNB) and tetracyanopyrazine (TCNP) in low-temperature argon matrices were measured with a Fourier-transform infrared (FTIR) spectrophotometer. The produced transient species were identified as the lowest electronically excited triplet states, T1, by a comparison of the observed infrared spectra with the calculated spectral patterns obtained by the hybrid density-functional-theory (DFT) method. The vibrational wavenumbers of the asymmetric C≡N stretching modes in the T1 states were found to be shifted to the low-wavenumber side by about 150 cm−1, indicating that the bonds of the cyano groups, –C≡N, in the T1 states are close to cumulative double bonds, C=C=N. This observation is supported by calculations of the optimized geometrical structures and the Mulliken spin density obtained by the DFT method.
Structure and Physical Properties of Low-Dimensional Molecular Conductors, [PXX][FeIII(Pc)(CN)2] and [PXX][CoIII(Pc)(CN)2] (PXX = peri-xanthenoxanthene, Pc = phthalocyaninato)
Authors: Matsuda Masaki , Asari Takehiro , Naito Toshio , Inabe Tamotsu , Hanasaki Noriaki , Tajima Hiroyuki 
Published: October 2003

Abstract
A novel low-dimensional molecular conductor, [PXX][FeIII(Pc)(CN)2], has been synthesized. This salt contains the magnetic FeIII ion (S = 1/2), and is isomorphous with [PXX][CoIII(Pc)(CN)2] which includes the non-magnetic CoIII ion. In both salts, the [MIII(Pc)(CN)2] (M = Fe or Co) units form a two-leg ladder chain. The two salts exhibit a similar temperature dependence of the thermoelectric power and a similar reflectance spectrum. The FeIII salt shows semiconducting behavior in its electrical resistivity over the temperature range measured, while the isomorphous CoIII salt exhibits metallic behavior in its resistivity above 100 K. The difference in the transport properties between the two salts suggests that the conduction electrons in the FeIII salt are seriously scattered by the local magnetic moment. Spontaneous magnetization is observed below 8 K in the FeIII salt. Upon applying a magnetic field, the resistivity of the FeIII salt drastically decreases below 50 K. The decrease in the resistivity is highly anisotropic to the field orientation. The field orientation dependence is highly consistent with the g-tensor anisotropy in the [FeIII(Pc)(CN)2] unit, suggesting that the negative magnetoresistance originates from the large π–d interaction self-contained in the [FeIII(Pc)(CN)2] unit.
Synthesis and Structural Characterization of 2,5-Bis(N-aryliminomethyl)pyrrolyl Complexes of Aluminum
Authors: Matsuo Yutaka , Tsurugi Hayato , Yamagata Tsuneaki , Tani Kazuhide , Mashima Kazushi 
Published: October 2003

Abstract
Reaction of tridentate ligands, 2,5-bis(N-aryliminomethyl)pyrroles (1a–e), with 1 equiv of AlMe3 in toluene afforded aluminum dimethyl complexes, AlMe2[2,5-bis(N-aryliminomethyl)pyrrolyl] (2a–e) with the release of one equiv of methane. In solution the aluminum complexes 2a–e showed Cs-symmetry as characterized by their 1H NMR spectra, while in solid the geometry around the Al atom as crystallographically determined for 2a and 2b was found to a tetrahedral by an amido nitrogen atom of the pyrrolyl anion, a nitrogen atom of one of two imino groups and two methyl groups. The aluminum complex 2e upon activated by one equiv of B(C6F5)3 became a catalyst for ethylene polymerization (Activity = 80 g-PE/mol-cat·h).
Syntheses and Structural Analyses of 1,3-Diphenyldisiloxanes as a Building Block of Silsesquioxanes
Authors: Seto Isamu , Gunji Takahiro , Kumagai Kaoru , Arimitsu Koji , Abe Yoshimoto 
Published: October 2003

Abstract
Syntheses of novel 1,3-diphenyldisiloxanes were investigated. 1,1,3,3-Tetrachloro-1,3-diphenyldisiloxane (1) and 1,1,3,3-tetraisocyanato-1,3-diphenyldisiloxane (2) were obtained by vapor-phase hydrolytic condensation of trichloro(phenyl)silane and triisocyanato(phenyl)silane, respectively. The reactions of 1 with 2-propanol, t-butyl alcohol, and diethylamine provided 1,1,3,3-tetraisopropoxy-1,3-diphenyldisiloxane (3), 1,3-di-t-butoxy-1,3-dichloro-1,3-diphenyldisiloxane (5a), and 1,1,3,3-tetrakis(diethylamino)-1,3-diphenyldisiloxane (6), respectively. 1,3-Diisocyanato-1,3-diisopropoxy-1,3-diphenyldisiloxane (4) and 1,3-di-t-butoxy-1,3-diisocyanato-1,3-diphenyldisiloxane (5b) were synthesized by the reactions of 2 with 2-propanol and with t-butyl alcohol, respectively. Hydrolysis of 5a or 5b afforded 1,3-di-t-butoxy-1,3-diphenyldisiloxane-1,3-diol (7). 1,3-Diphenyldisiloxane-1,1,3,3-tetrol (8) was isolated from the hydrolysis of 1. A single crystal X-ray diffraction of 8 showed that four hydroxy groups are facing each other to form a ladder-type network by the intermolecular hydrogen bondings.
Polar Effect on the Stacking Interaction between a Zinc Complex of an Anionic Porphyrin and Anionic Aromatics
Authors: Kano Koji , Kobayashi Shiho 
Published: October 2003

Abstract
Although 2-anthracenesulfonate did not interact with a zinc complex of 5,10,15,20-tetrakis(p-sulfonatophenyl)porphyrin (ZnTPPS), anthraquinone-2-sulfonate (AQS) and -2,6-disulfonate (AQDS) formed stable molecular complexes with ZnTPPS in aqueous solution. Such results suggest the polar effect on the stacking interaction between aromatic compounds. Molecular complexation of ZnTPPS was further studied using mono-substituted benzoate anions as the partners by means of 1H NMR spectroscopy. The electron-withdrawing groups of the benzoates stabilized the complexes, while the electron-donating groups restrained the complexation. These results suggest that a reduction of the electrostatic repulsion by electron-withdrawing group(s) is important to form stable molecular complexes of ZnTPPS and anionic aromatics via the London dispersion force. A similar mechanism could be applied to the formation of the AQS dimer, which takes a slipped edge-to-edge arrangement.
Substantive intumescence from phosphorylated 1,3‐propanediol derivatives substituted on to cellulose
Authors: Zhang Sheng , Horrocks A. Richard 
Published: October 2003

AbstractCellulose flame retarded with an ammonia‐cured, polycondensed tetrakis(hydroxymethyl)phosphonium–urea derivative (as Proban CC®, Rhodia) phosphorylated by cyclic 1,3‐propanediol phosphoryl chloride and cyclic 2,2‐diethyl‐1,3‐propanediol phosphoryl chloride can give phosphorus levels up to 6.9% (w/w). Such high levels suggest up to 35.5% yields of reaction if the free secondary amine groups present in the crosslinked flame retardant and the C(6) primary hydroxyl groups are the assumed phosphorylation sites. The presence of substituted propanediol phosphonate moieties in the fibers significantly increases char formation above 400©C and scanning electron microscopy indicates that the char has an intumescent structure. The influence of the chemical structure of the propanyl moeity to the reaction extent of the possible phosphorylation sites and the char formation mechanism during thermal pyrolysis of the modified samples are discussed. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3165–3172, 2003