bluuebunny/crossref_metadata_2025 huggingface dataset:
Approaches to the mechanisms of song memorization and singing provide evidence for a procedural memory
Authors: Hultsch Henrike , Todt Dietmar
Published: April 2005

There is growing evidence that, during song learning, birds do not only acquire 'what to sing' (the inventory of behavior), but also 'how to sing' (the singing program), including order-features of song sequencing. Common Nightingales Luscinia megarhynchos acquire such serial information by segmenting long strings of heard songs into smaller subsets or packages, by a process reminiscent of the chunking of information as a coding mechanism in short term memory. Here we report three tutoring experiments on nightingales that examined whether such 'chunking' was susceptible to experimental cueing. The experiments tested whether (1) 'temporal phrasing' (silent intersong intervals spaced out at particular positions of a tutored string), or (2) 'stimulus novelty' (groups of novel song-types added to a basic string), or (3) 'pattern similarity' in the phonetic structure of songs (here: sharing of song initials) would induce package boundaries (or chunking) at the manipulated sequential positions. The results revealed cueing effects in experiments (1) and (2) but not in experiment (3). The finding that birds used temporal variables as cues for chunking does not require the assumption that package formation is a cognitive strategy. Rather, it points towards a mechanism of procedural memory operating in the song acquisition of birds.
Evidence of tutoring in the development of subsong in newly-fledged Meyer's Parrots Poicephalus meyeri
Authors: Masin Simone , Massa Renato , Bottoni Luciana
Published: April 2005

Subsongs are vocal trials uttered by young birds to practice songs. Among songbirds, subsongs are displayed by individuals in their first year of life. Studies on Zebra Finches Poephila guttata suggest that the juveniles learn their songs from a vocal tutor, their father. In this study we examine the subsongs in six captive-born Meyer's Parrots Poicephalus meyeri, from fledging time to weaning. Recordings of songs from chicks and fathers were analyzed for similarities in frequency and time parameters. With age, the subsongs of the chicks became more similar to the vocalizations of the fathers with 20% similarity rating in the first week after fledging to 100% at weaning time. Moreover, fledged chicks were exposed to a wide range of stimuli from several species of parrots breeding pairs caged nearby but chicks exclusively learned their fathers' songs. Our data support the hypothesis that Meyer's Parrots are vocal learners and use their father as their tutor.
A memory like a female Fur Seal: long-lasting recognition of pup's voice by mothers
Authors: Mathevon Nicolas , Charrier Isabelle , Aubin Thierry
Published: April 2005

In colonial mammals like fur seals, mutual vocal recognition between mothers and their pup is of primary importance for breeding success. Females alternate feeding sea-trips with suckling periods on land, and when coming back from the ocean, they have to vocally find their offspring among numerous similar-looking pups. Young fur seals emit a 'mother-attraction call' that presents individual characteristics. In this paper, we review the perceptual process of pup's call recognition by Subantarctic Fur Seal Arctocephalus tropicalis mothers. To identify their progeny, females rely on the frequency modulation pattern and spectral features of this call. As the acoustic characteristics of a pup's call change throughout the lactation period due to the growing process, mothers have thus to refine their memorization of their pup's voice. Field experiments show that female Fur Seals are able to retain all the successive versions of their pup's call.
Are communication activities shaped by environmental constraints in reverberating and absorbing forest habitats?
Authors: Manthevon Nicolas , Aubin Thierry , Dabelsteen Torben , Vielliar Jacques M.E.
Published: April 2005

In the dense vegetation of temperate or tropical forests, communication processes are constrained by propagation-induced modifications of the transmitted sounds. The presence of leaves, trunks and branches induces important sound reverberation and absorption leading to diminution of the signal energy as well as qualitative modifications. The aim of this paper is to briefly review the different strategies used by birds to manage with these constraints. At the emitter's level, an adapted emission behavior which takes into account both the physical heterogeneities of the forest environment and the temporal variations of the acoustic constraints, is especially useful to control the active space of signaling. The coding of information into acoustic parameters that have different susceptibility to propagation constraints is also of great interest. At the receiver's level, an adaptive reception behavior (listening post) and a great tolerance to sound degradation during the decoding process are the keys to an optimal communication process.
Causes and consequences of song amplitude adjustment in a territorial bird: a case study in nightingales
Authors: Brumm Henrik
Published: April 2005

Vocal amplitude, one of the crucial factors for the exchange of acoustic signals, has been neglected in studies of animal communication, but recent studies on song variation in Common Nightingales Luscinia megarhynchos have revealed new insights into its importance in the singing behavior of territorial birds. In nightingales song amplitude is not maximized per se, but is individually regulated according to the level of masking background noise. Also, birds adjust their vocal intensity according to social variables, as in male-male interactions. Moreover, during such interactions, males exploited the directionality of their songs to broadcast them in the direction of the intended receivers ensuring the most effective signal transmission. Studies of the development of this typical long-range signaling suggest that sound level is highly interrelated with overall developmental progression and learning, and thus should be viewed as an integral part of song ontogeny. I conclude that song amplitude is a dynamic feature of the avian signal system, which is individually regulated according to the ecological demands of signal transmission and the social context of communication.
Complex communication signals: the case of the Blue-black Grassquit Volatinia jacarina (Aves, Emberizidae) song. Part I - A structural analysis
Authors: Fandiño-Mariño Hernán , Vielliard Jacques M.E.
Published: April 2005

The song of the Blue-black Grassquit Volatinia jacarina is different for every individual and the structural differences between individuals are quite complex. Samples of songs from different Brazilian localities, as well as from Venezuela and Mexico, were studied through a comparative analysis of their sonograms. From the structural point of view, the results show a song composed of a single note that is compacted in a ''window'' between 2 and 13 kHz and rarely occupying more than half of a second. The note is essentially pure and is repeatedly uttered with a high level of fidelity. A global frequency modulation decreases from the beginning to the end of the song. The main song components are referred to as ''Blocks'' and are of three types: ''Vibrations'' (Buzzes or Vibratos), ''Arabesques'' (complex notes) and ''Isolated Modulations'' (simple syllables). Among other characteristics are double voices, which are quite diverse and probably function as codes for individual recognition. This song is considered a special case where a signature system has been developed to a high level of inter-individual variability.
Comparative analysis of the song of the Rufous-collared Sparrow Zonotrichia capensis (Emberizidae) between Campinas and Botucatu, São Paulo State, Brazil
Authors: Avelino Márcio F. , Vielliard Jacques M.E.
Published: April 2005

The regional dialects or regiolects of the Rufous-collared Sparrow Zonotrichia capensis were compared between Campinas (47º06'W-22º90'S) and Botucatu (48º44'W-22º88'S), São Paulo State, Southeastern Brazil. Songs of 88 individuals from thirteen localities were recorded. Sonograms showed that two areas presented more homogeneous songs, forming two regiolects. In 11 localities most individuals shared the same song type. At the other two localities, they sang up to 5 different song types. This occurs at the boundaries of the regiolects, and was also where individuals singing more than one song type were found. Similarities between song types were not related to geographic distance between the respective singers. A comparative analysis showed similarities in these regiolects with song of populations from Northeastern Brazil.
Acoustic communication in the Red-vented Bulbul Pycnonotus cafer
Authors: Kumar Anil
Published: April 2005

This paper deals with acoustic communication in the Red-vented Bulbul Pycnonotus cafer. This species emits a high variety of vocal signals that can be classified on the basis of their acoustical features and context of production. Individuals sang throughout the year and most songs were discrete and stereotyped. The songs were composed of strophes (phrases) with minor structural variations of elements that were preceded and followed by a temporal gap (3 to 12s). Most strophes were composed of 2 to 6 elements that were often dissimilar in structure and ranging from 0.98 to 4.5 kHz. The biological function of the song appeared to be to maintain pair bonds and to synchronize breeding activities. Different types of context-specific calls were identified. Individuals produced Type-I alarm calls (fast and wide-band, 1.03 to 6.36 kHz) under low predation pressure andType-II calls (narrowfrequency range, 1.37 to 3.39 kHz) under high predation pressure. Roosting calls were fast and wide-band signals phonetically similar to Type-I alarm calls. Three types of begging/contact calls were recorded in nestlings/fledglings. Greeting calls and flight calls were composed of complex phrases, like song, but were short and used for proximate functions.
Long-distance calls in Neotropical primates
Authors: Oliveira Dilmar A.G. , Ades César
Published: April 2005

Long-distance calls are widespread among primates. Several studies concentrate on such calls in just one or in few species, while few studies have treated more general trends within the order. The common features that usually characterize these vocalizations are related to long-distance propagation of sounds. The proposed functions of primate long-distance calls can be divided into extragroup and intragroup ones. Extragroup functions relate to mate defense, mate attraction or resource defense, while intragroup functions involve group coordination or alarm. Among Neotropical primates, several species perform long-distance calls that seem more related to intragroup coordination, markedly in atelines. Callitrichids present long-distance calls that are employed both in intragroup coordination and intergroup contests or spacing. Examples of extragroup directed long-distance calls are the duets of titi monkeys and the roars and barks of howler monkeys. Considerable complexity and gradation exist in the long-distance call repertoires of some Neotropical primates, and female long-distance calls are probably more important in non-duetting species than usually thought. Future research must focus on larger trends in the evolution of primate long-distance calls, including the phylogeny of calling repertoires and the relationships between form and function in these signals.
Bioacoustics of human whistled languages: an alternative approach to the cognitive processes of language
Authors: Meyer Julien
Published: April 2005

Whistled languages are a valuable heritage of human culture. This paper gives a first survey about a new multidisciplinary approach to these languages. Previous studies on whistled equivalents of languages have already documented that they can provide significant information about the role of rhythm and melody in language. To substantiate this, most whistles are represented by modulations of frequency, centered around 2000 Hz (±1000 Hz) and often reach a loudness of about 130 dB (measured at 1m from the source). Their transmission range can reach up to 10 km (as verified in La Gomera, Canary Island), and the messages can remain understandable, even if the signal is deteriorated. In some cultures the use of whistled language is associated with some "talking musical instruments" (e.g. flutes, guitars, harps, gongs, drums, khens). Finally, whistles as a means of conveying information have some analogues in the animal kingdom (e.g. some birds, cetaceans, primates), providing opportunities to compare the acoustic characteristics of the respective signals. With such properties as a reference, the project reported here has two major tasks: to further elucidate the many facets of whistled language and, above all, help to immediately stop the process of its gradual disappearance.
Identification of Tibicen cicada species by a Principal Components Analysis of their songs
Authors: Ohya Eiji
Published: April 2005

Specific identification of three Tibicen cicadas, T. japonicus, T. flammatus and T. bihamatus, by their chirping sounds was carried out using Principal Components Analysis (PCA). High quality recordings of each species were used as the standards. The peak and mean frequencies and the pulse rate were used as the variables. Out of 12 samples recorded in the fields one fell in the vicinity of T. japonicus and all other were positioned near T. bihamatus. Then the cluster analysis of the PCA scores clearly separated each species and allocated the samples in the same way.
Application of automated bioacoustic identification in environmental education and assessment
Authors: Oba Teruyo
Published: April 2005

Developments in electronics and computer science have led to the introduction of an automated bioacoustic identification device used to resolve commonly encountered problems in the identification of animal species in the field. This technology aids our auditory observations, and also improves the quality of biological surveys and environmental monitoring. In this paper the future roles and possibilities of bioacoustics are discussed, providing some examples from the realm of environmental education and monitoring that focus on the use of nature sounds.
A remark on soliton equation of mean curvature flow
Authors: Ma Li , Yang Yang
Published: April 2005

In this note, we consider self-similar immersions of the mean curvature flow and show that a graph solution of the soliton equation, provided it has bounded derivative, converges smoothly to a function which has some special properties (see Theorem 1.1).
Finite approximate controllability for semilinear heat equations in noncylindrical domains
Authors: Menezes Silvano B. de , Limaco Juan , Medeiros Luis A.
Published: April 2005

We investigate finite approximate controllability for semilinear heat equation in noncylindrical domains. First we study the linearized problem and then by an application of the fixed point result of Leray-Schauder we obtain the finite approximate controllability for the semilinear state equation.
Chemical constituents from Vellozia graminifolia (Velloziaceae)
Authors: Branco Alexsandro , Pinto Angelo C. , Braz Filho Raimundo
Published: April 2005

From the hexane and ethyl acetate extracts obtained from stems, roots and leaf sheaths of Vellozia graminifolia, a mixture of linear hydrocarbons, a mixture of pentacyclic triterpenes, five monoisoprenylated flavonoids and one labdane diterpene, (-)-ent-3beta-hydroxy-8(17)-labden-15-oic acid, were isolated. The linear hydrocarbons and minor triterpenes were identified in their corresponding mixtures by High Resolution Gas Chromatography (HRGC) and HRGC coupled to mass spectrometry. The major pentacyclic triterpenes and the diterpene were characterized by spectral data, including 2D NMR experiments, and chemical transformations.
Effects of insulin and actin on phosphofructokinase activity and cellular distribution in skeletal muscle
Authors: Silva Ana Paula P. , Alves Gutemberg G. , Araújo Alexandre H.B. , Sola-Penna Mauro
Published: April 2005

In this work, we report evidences that the association of phosphofructokinase and F-actin can be affected by insulin stimulation in rabbit skeletal muscle homogenates and that this association can be a mechanism of phos-phofructokinase regulation. Through co-sedimentation techniques, we observed that on insulin-stimulated tissues, approximately 70% of phosphofructokinase activity is co-located in an actin-enriched fraction, against 28% in control. This phenomenon is accompanied by a 100% increase in specific phosphofructokinase activity in stimulated homogenates. Purified F-actin causes an increase of 230% in phosphofructokinase activity and alters its kinetic parameters. The presence of F-actin increases the affinity of phosphofructokinase for fructose 6-phosphate nevertheless, with no changes in maximum velocity (Vmax). Here we propose that the modulation of cellular distribution of phosphofructokinase may be one of the mechanisms of control of glycolytic flux in mammalian muscle by insulin.
The transition from memory retrieval to extinction
Authors: Cammarota Martín , Barros Daniela M. , Vianna Mónica R.M. , Bevilaqua Lia R.M. , Coitinho Adriana , Szapiro Germán , Izquierdo Luciana A. , Medina Jorge H. , Izquierdo Iván
Published: April 2005

Memory is measured by measuring retrieval. Retrieval is often triggered by the conditioned stimulus (CS); however, as known since Pavlov, presentation of the CS alone generates extinction. One-trial avoidance (IA) is a much used conditioned fear paradigm in which the CS is the safe part of a training apparatus, the unconditioned stimulus (US) is a footshock and the conditioned response is to stay in the safe area. In IA, retrieval is measured without the US, as latency to step-down from the safe area (i.e., a platform). Extinction is installed at the moment of the first unreinforced test session, as clearly shown by the fact that many drugs, including PKA, ERK and protein synthesis inhibitors as well as NMDA receptor antagonists, hinder extinction when infused into the hippocampus or the basolateral amygdala at the moment of the first test session but not later. Some, but not all the molecular systems required for extinction are also activated by retrieval, further endorsing the hypothesis that although retrieval is behaviorally and biochemically necessary for the generation of extinction, this last process constitutes a new learning secondary to the unreinforced expression of the original trace.
Approximate Entropy as a measure of complexity in sap flow temporal dynamics of two tropical tree species under water deficit
Authors: Souza Gustavo M. , Ribeiro Rafael V. , Santos Mauro G. , Ribeiro Henrique L. , Oliveira Ricardo F.
Published: April 2005

Approximate Entropy (ApEn), a model-independent statistics to quantify serial irregularities, was used to evaluate changes in sap flow temporal dynamics of two tropical species of trees subjected to water deficit. Water deficit induced a decrease in sap flow of G. ulmifolia, whereas C. legalis held stable their sap flow levels. Slight increases in time series complexity were observed in both species under drought condition. This study showed that ApEn could be used as a helpful tool to assess slight changes in temporal dynamics of physiological data, and to uncover some patterns of plant physiological responses to environmental stimuli.
Cones in the Euclidean space with vanishing scalar curvature
Authors: Barbosa João Lucas M. , Carmo Manfredo do
Published: April 2005

Given a hypersurface M on a unit sphere of the Euclidean space, we define the cone based on M as the set of half-lines issuing from the origin and passing through M. By assuming that the scalar curvature of the cone vanishes, we obtain conditions under which bounded domains of such cone are stable or unstable.
Gap junctions in hematopoietic stroma control proliferation and differentiation of blood cell precursors
Authors: Bodi Estevão , Hurtado Sandra P. , Carvalho Marcelo A. , Borojevic Radovan , Carvalho Antônio C. Campos de
Published: April 2005

We examined gap junction communication in an in vitro model of hematopoiesis, using the murine bone marrow stroma cell line S-17, and primary cultures of murine marrow-derived blood cell precursors. S-17 cells express several connexins, the major one being connexin 43. Connexin expression and formation of functional gap junctions is modulated by stroma cell density. Transfection of S-17 cells with a vector containing connexin 43 sense or anti-sense sequences increased or decreased, respectively, connexin 43 synthesis and intercellular dye coupling. Under these conditions, modulation of gap junction-mediated communication modified the growth pattern of stroma itself, as well as the ability of the stroma to sustain hematopoiesis. Increased connexin 43 expression was associated with a delay in differentiation of blood cells, resulting in increased production of hematopoietic precursors, while decreased connexin 43 expression elicited an accelerated differentiation of myeloid blood cell precursor cells. These results suggest that connexin-mediated coupling in the stroma modulates the ratio between proliferation and differentiation of hematopoietic precursors. We therefore propose that increased gap junction communication in the stroma elicits an enhanced production of immature bone marrow cells through the delay in their terminal differentiation, inducing consequently an extended proliferation period of blood cell precursors.
SHRIMP U-Pb zircon dating of Pedras Grandes Suite, southern Santa Catarina State, Brazil
Authors: Jelinek Andréa R. , Bastos-Neto Artur C. , Leite Jayme A.D. , Hartmann Léo A. , McNaughton Neal J.
Published: April 2005

Two major magmatic pulses of the granitic Florianópolis Batholith in Santa Catarina State, southern Brazil, occurred between 613±5Ma and 595±5 Ma, during the Neoproterozoic Brasiliano Cycle. These ages were obtained by U-Pb isotopic determinations with the sensitive high mass-resolution ion microprobe on igneous zircons from Pedras Grandes Suite in Santa Catarina State. Euhedral zircons remained unaltered close to a fluorite vein deposited at 180?C or more. These ages suggest a northern limit for the Pedras Grandes Suite, explaining the spatial relationship between the fluorite veins and the source rock.
Mineral chemistry of tantalate species new in the Borborema Pegmatitic Province, Northeast Brazil
Authors: Beurlen Hartmut , Soares Dwight R. , Thomas Rainer , Prado-Borges Lucila E. , Castro Cláudio de
Published: April 2005

Tantalate samples, supposedly of the columbite group, were collected in the Borborema Pegmatitic Province, aiming to test the Mn/(Mn+Fe) and Ta/(Ta+Nb) ratios as geochemical indicators of pegmatite fractionation. Surprisingly, preliminary microprobe data allowed recognizing some species, so far unknown in the Province, namely titanian ixiolite, fersmite, brannerite, strüverite, natrobistantite, plumbo- and stibiomicrolite, plumboand uranpyrochlore. The identification of these exotic tantalates with unusual composition, in addition to its distribution in several pegmatites, far from the classical Alto do Giz and Seridozinho pegmatites, indicate that the elevated degree of fractionation is not restricted to these two occurrences but may be reached in other pegmatite areas of the Province. It indicates also that this degree of fractionation may be very variable between pegmatites in small areas. The zoning patterns observed in the titanian ixiolite, with Ti and Nb enrichment at the borders at expense of Ta enriched in the core, are also quite unusual and reverse in comparison with the normal trend of progressive Ta and Mn enrichment in tantalates with the degree of fractionation. A similar "reverse" trend was observed in titanian wodginite of petalite/pollucite bearing pegmatites of the Separation Rapids Province in Ontario, Canada.
Supercritical Water as a Solvent
Authors: Weingärtner Hermann , Franck Ernst Ulrich
Published: April 2005

Water is not restricted to moderate temperatures and low pressures, but can exist up to very high temperatures, far above its critical point at 647 K. In this supercritical regime, water can be gradually compressed from gas‐like to liquid‐like densities. The resulting dense supercritical states have extraordinary properties which can be tuned by temperature and pressure, and form the basis for innovative technologies. This Review covers the current knowledge of the major properties of supercritical water and its solutions with nonpolar, polar, and ionic compounds, and of the underlying molecular processes.
Cover Picture: Self‐Assembly and Cross‐Linking of Bionanoparticles at Liquid–Liquid Interfaces (Angew. Chem. Int. Ed. 16/2005)
Authors: Russell Justin T. , Lin Yao , Böker Alexander , Su Long , Carl Philippe , Zettl Heiko , He Jinbo , Sill Kevin , Tangirala Ravisubhash , Emrick Todd , Littrell Kenneth , Thiyagarajan Pappannan , Cookson David , Fery Andreas , Wang Qian , Russell Thomas P.
Published: April 2005

Interfacial activities of the cowpea mosaic virus (CPMV) between two immiscible liquids are examined by fluorescent labeling. The cover picture shows a ribbon diagram of CPMV, fluorescence laser scanning confocal microscopy images of perfluorodecalin droplets in water encapsulated by a layer of CPMV, and the structure of a CPMV particle labeled with a fluorescent dye and biotin. In their Communication on page 2420 ff., T. P. Russell, Q. Wang, and co‐workers describe the formation of robust membranes by the self‐assembly of CPMV bionanoparticles at liquid–liquid interfaces.
Determination of New Group Contributions to Calculate Limiting Oxygen Concentrations
Authors: Fuß O. , Molnarne M. , Schröder V. , Schönbucher A.
Published: April 2005

A few years ago, Subramaniam and Cangelosi published a group contribution method for calculating the limiting oxygen concentration (LOC) of combustible gases. In the present article, these LOC values are compared with recommended values from the database CHEMSAFE, measured experimentally according to German standard DIN 51649. Evaluation of the results shows that the calculated LOCs differ widely from those taken from CHEMSAFE, so that the group contribution values of some substances have to be redetermined on the basis of the more recent data material.
Dosing Pumps with Innovative Drive Concept
Authors: Eggert B.
Published: April 2005

Displacement pumps of the DME and DMS types offer quite a number of valuable advantages useful for the chemical and process industries. They have a wide setting range, with constant dosing accuracy. The cam‐crank drive eliminates the water hammer problem of solenoid driven diaphragm pumps.
Enhance Cyanide Recovery by UsingAir‐Sparged Hydrocyclone
Authors: Parga Torres J.R. , Cocke D.L.
Published: April 2005

Human health and environmental concerns dictate that industrial processes be improved or replaced. Recovery or recycling is an important activity that allows cyanide residue from the industrial processes to be re‐used, reducing its production cost and disposal problems. In this regard, the air‐sparged hydrocyclone (ASH) has been used as a reactor for the treatment of cyanide solutions for cyanide recycling by acidification/volatilization using the Mexican modification of the Mills‐Crowe process. Aqueous cyanide‐ion concentration can be reduced from 250 ppm to below 20 ppm in the ASH with recoveries greater than 80 % in a single stage.
Tuning Photoinduced Energy‐ and Electron‐Transfer Events in Subphthalocyanine–Phthalocyanine Dyads
Authors: González‐Rodríguez David , Claessens Christian G. , Torres Tomas , Liu Shenggao , Echegoyen Luis , Vila Nuria , Nonell Santi
Published: April 2005

A series of subphthalocyanine–phthalocyanine dyads has been prepared by means of palladium‐catalyzed cross‐coupling reactions between a monoalkynylphthalocyanine and different monoiodosubphthalocyanines. Electronic coupling between the two photoactive units is ensured by a rigid and π‐conjugated alkynyl spacer. In addition, the electronic characteristics of the subphthalocyanine moiety were modulated by the introduction of different peripheral substituents. Cyclic and Osteryoung square‐wave voltammetry experiments revealed that the reduction potential of this subunit can be decreased by about 400 mV on going from thioether or no substituents to nitro groups. As a consequence, the energy level of the charge‐transfer state could be fine‐tuned so as to gain control over the fate of the photoexcitation energy in each subunit. The diverse steady‐state and time‐resolved photophysical techniques employed demonstrated that, when the charge‐transfer state lies high in energy, a quantitative singlet–singlet energy‐transfer mechanism from the excited subphthalocyanine to the phthalocyanine takes place. On the contrary, stabilization of the radical pair by lowering the redox gap between electron donor and acceptor results in a highly efficient photoinduced electron‐transfer process, even in solvents of low polarity such as toluene (ΦET≈0.9). These features, together with the extraordinary absorptive cross section that these molecular ensembles display across the whole UV/Vis spectrum, make them model candidates for application in situations where broadband light sources are needed.
Assembly of Heteropoly Acid Nanoparticles in SBA‐15 and Its Performance as an Acid Catalyst
Authors: Yu Shu‐Yuan , Wang Li‐Ping , Chen Bo , Gu Ying‐Ying , Li Jing , Ding Han‐Ming , Shan Yong‐Kui
Published: April 2005

Keggin‐type 12‐tungstophosphoric acid (TPA) nanocrystals have been assembled inside the pores of mesoporous silica through a vacuum impregnation method by using large‐pore SBA‐15 as a nanoreactor. The product was characterized by Brunauer–Emmet–Teller particle size distribution (BET‐PSD), NMR and FT‐IR spectroscopy, X‐ray diffraction (XRD), tranmsission electron microscopy (TEM), differential thermal analysis (DTA) and FT‐IR of adsorbed pyridine. The experimental results illustrate that the TPA nanocrystals are excellent Brønsted acid catalytic materials at room temperature.
Influence of dT20 and [d(AT)10]2 on Cisplatin Hydrolysis Studied by Two‐Dimensional [1H,15N] HMQC NMR Spectroscopy
Authors: Vinje Jo , Sletten Einar , Kozelka Jiří
Published: April 2005

The influence of the presence of DNA on the kinetics of cisplatin (cis‐[PtCl2(NH3)2]) aquation (replacement of Cl− by H2O) and anation (replacement of H2O by Cl−) involved in the hydrolysis of cisplatin have been determined by two‐dimensional [1H,15N] HMQC NMR spectroscopy. Single‐stranded dT20 and double‐stranded [d(AT)10]2 oligonucleotides were used as DNA models, avoiding guanines which are known to react rapidly with aquated cisplatin forms. Reactions starting from cis‐[PtCl2(15NH3)2], or from a stoichiometric mixture of cis‐[Pt(15NH3)2(H2O)2]2+ and Cl− (all 0.5 mM PtII; in ionic strength, adjusted to 0.095 M or 0.011 M with NaClO4, pH between 3.0 and 4.0) were followed in an NMR tube in both the absence and presence of 0.7 mM dT20 or [d(AT)10]2. In the presence of dT20, we observed a slight and ionic‐strength‐independent decrease (15–20 %) of the first aquation rate constant, and a more significant decrease of the second anation rate constant. The latter was more important at low ionic strength, and can be explained by efficient condensation of cis‐[Pt(15NH3)2(H2O)2]2+ on the surface of single‐stranded DNA, in a region depleted of chloride anions. At low ionic strength, we observed an additional set of [1H,15N] HMQC spectral signals indicative of an asymmetric species of PtN2O2 coordination, and we assigned them to phosphate‐bound monoadducts of cis‐[Pt(15NH3)2(H2O)2]2+. Double‐stranded [d(AT)10]2 slowed down the first aquation step also by approximately 15 %; however, we could not determine the influence on the second hydrolysis step because of a significant background reaction with cis‐[Pt(NH3)2(H2O)2]2+.
Preparation of a chiral ferrocenyl derivative containing a biphenyl unit via nickel‐mediated homocoupling
Authors: Patti Angela , Pedotti Sonia
Published: April 2005

Ferrocenyl derivative 2, which possesses a biphenyl unit, was prepared by nickel(0)‐mediated homocoupling of a chiral ferrocenyloxazoline. Compound 2 exists as an equilibrium mixture of two diastereomers, in a ratio dependent on temperature and solvent, due to the partially hindered rotation around biaryl bond. Upon complexation with Cu(I) or Zn(II), complete fixation of the stereogenic axis was obtained and a single stable atropoisomer was formed, whose absolute configuration was assigned on the basis of its NOESY spectrum. The 2–Cu(I) complex was used as catalyst in the cyclopropanation of styrene. Chirality 17:233–236, 2005. © 2005 Wiley‐Liss, Inc.
Expression and structure of interleukin 4 receptors in primary meningeal tumors
Authors: Puri Sachin , Joshi Bharat H. , Sarkar Chitra , Mahapatra Ashok Kumar , Hussain Ejaz , Sinha Subrata
Published: April 2005

BACKGROUND

It was reported previously that malignant human tumors, like glioma and medulloblastoma, express high‐density interleukin (IL‐4) receptor mRNA and protein. Because IL‐4 receptors (R) are sensitive targets for targeted therapeutics, knowledge of the expression of these receptors in other central nervous system tumors is of great interest. In this study, the authors examined the expression and subunit composition of IL‐4R complex in primary human meningiomas.

METHODS

Reverse transcription‐polymerase chain reaction (RT‐PCR) analysis for IL‐13Rα1, IL‐4Rα and IL‐2Rγc was performed on total RNA extracted from 35 meningiomas and a normal human brain tissue sample. Results were confirmed in nine randomly selected tumors by quantitative real‐time PCR and in situ immunofluorescence assay.

RESULTS

Transcripts for the IL‐4Rα and IL‐13Rα1 chains were overexpressed in meningiomas compared with normal brain tissue. The levels of IL‐4Rα mRNA appeared to be higher compared with the levels of IL‐13Rα1 mRNA. The results also showed that tumors with higher disease grade tended to have increased mRNA expression for the IL‐4Rα chain. This IL‐4Rα mRNA overexpression appeared to be more frequent in younger patients (age < 37 years). The transcripts for IL‐2Rγc chain were not detected in any of the tumor samples or in normal brain tissue. Quantitative real‐time PCR confirmed the results of the RT‐PCR analysis. Meningiomas also demonstrated a bright immunofluorescent staining for the IL‐4Rα and IL‐13Rα1 chains but no staining for IL‐2Rγc.

CONCLUSIONS

Expression of the IL‐4Rα and IL‐13Rα1 chains and absence of IL‐2γc expression established that meningiomas expressed type II IL‐4Rs. These receptors may serve as a target for cytotoxin/immunotoxin therapy in patients with meningioma who are not amenable to surgical resection or for recurrent tumors. Cancer 2005. © 2005 American Cancer Society.
Modulation of tamoxifen sensitivity by antisense Bcl‐2 and trastuzumab in breast carcinoma cells
Authors: Kim Ryungsa , Tanabe Kazuaki , Emi Manabu , Uchida Yoko , Toge Tetsuya
Published: April 2005

BACKGROUND

Because the overexpression of HER‐2 and Bcl‐2 is associated with resistance to tamoxifen (TAM), the authors examined the effect of antisense (AS) Bcl‐2 on sensitivity to TAM compared with the effect of trastuzumab on sensitivity to TAM in breast carcinoma cell lines.

METHODS

Drug sensitivity was assessed in vitro using a [3‐4,5‐dimethylthiazol‐2‐yl]‐2,5‐diphenyltetrazolium bromide assay with the breast carcinoma cell lines ZR‐75‐1, MDA‐MB‐453, and BT‐474. AS Bcl‐2 18‐mer phosphorothioate oligonucleotide was applied. Apoptotic cell death was assessed with the terminal deoxynucleotidyl transferase‐mediated biotinylated UTP nick‐end labeling method, and gene expression was evaluated with Western blot analysis.

RESULTS

The expression of Bcl‐2 was identified in ZR‐75‐1 and BT‐474 cells and, to a lesser extent, in MDA‐MB‐453 cells. Overexpression of HER‐2 was identified in BT‐474 cells, and moderate expression was identified in MDA‐MB‐453 and ZR‐75‐1 cells. Combination treatment with trastuzumab or AS Bcl‐2 enhanced TAM sensitivity in ZR‐75‐1 cells, which showed 50% inhibitory concentration (IC50) values of 0.9 μM (7.2‐fold increase) and 0.5 μM (13.0‐fold), respectively. Combination treatment with trastuzumab or AS Bcl‐2 slightly enhanced TAM sensitivity of BT‐474 cells, with IC50 values of 3.0 μM (1.3‐fold) and 1.5 μM (2.6‐fold), respectively. The sensitivity of MDA‐MB‐453 cells to TAM was not enhanced by combination with trastuzumab or AS Bcl‐2. Modulation of TAM sensitivity by AS Bcl‐2 was superior to modulation by trastuzumab in HER‐2‐expressing and Bcl‐2‐expressing breast carcinoma cells. Enhanced sensitivity in combination with AS Bcl‐2 was associated with down‐regulation of Bcl‐2 and pAkt, which was correlated with the induction of Bax and caspase‐3, leading to apoptosis.

CONCLUSIONS

AS Bcl‐2 appeared to be superior to trastuzumab with respect to regulating the signal‐transduction pathways involved in breast carcinoma cells. Cancer 2005. © 2005 American Cancer Society.
Prognostic value of CD44 isoform expression in thymic epithelial neoplasms
Authors: Sonobe Satoshi , Miyamoto Hideaki , Nobukawa Bunsei , Izumi Hiroshi , Futagawa Toshiro , Ishikawa Noboru , Yamazaki Akio , Uekusa Toshimasa , Abe Hiroshi , Suda Koichi
Published: April 2005

BACKGROUND

Many histologic classifications of thymic epithelial tumors have been reported to date, but to the authors' knowledge, none of them closely reflect the clinical behavior or prognosis of the tumor. Therefore, it is necessary to establish a biologic marker for thymic epithelial tumors. Variants of CD44 may be important in promoting tumor progression and metastasis. Accordingly, the expression of CD44 isoforms in thymic epithelial neoplasms was investigated using immunohistochemistry to assess their possible value as prognostic indicators.

METHODS

Expression of CD44v6 in thymic epithelial tumors was investigated with immunohistochemistry using consecutive surgical specimens resected from 108 patients between 1983 and 2002 at Juntendo University Hospital in Tokyo, Japan.

RESULTS

Among the 108 thymic epithelial tumors, 70 were negative for CD44v6, 20 were weakly positive, and 18 were strongly positive. The status of CD44v6 expression (negative vs. weakly plus strongly positive) was found to be correlated with the tumor stage according to the Masaoka staging system (noninvasive vs. invasive tumors) (P = 0.0214). When patients with tumors that were negative and weakly positive for CD44v6 expression were combined, the 5‐year, 10‐year, and 15‐year recurrence‐free survival rates were 98.2%, 95.9%, and 86.1%, respectively, whereas the corresponding rates for patients with strongly positive tumors were 73.5%, 73.5%, and 55.1%, respectively. Therefore, these two groups demonstrated a significant difference with regard to recurrence‐free survival (P = 0.0172).

CONCLUSIONS

CD44v6 expression in thymic epithelial neoplasms demonstrated a significant difference based on the World Health Organization classification, the Masaoka stage (invasive vs. noninvasive tumors), and recurrence, if an appropriate cutoff value was chosen in each case. This suggests that CD44v6 can be used as a marker that reflects the stage of thymic tumors. Cancer 2005. © 2005 American Cancer Society.
Design and characterization of a compact dual channel virus counter
Authors: Stoffel Carrie L. , Kathy Robin Finch , Rowlen Kathy L.
Published: April 2005

Background

Although there is a growing need in the field of biotechnology to rapidly and accurately quantify viruses, time‐consuming techniques such as the plaque titer method remain the “gold standard.” Flow cytometric methods for virus quantification offer the advantages of rapid analysis and statistical treatment. The technique presented in this work represents the first demonstration of a flow cytometric determination of a viral count that is directly related to the count obtained by plaque titer.

Methods

A flow cytometric instrument for rapid quantification of virus particles was designed, constructed, and thoroughly characterized. A two‐color method, which involved staining the viral genome and the protein coat for baculoviruses, was developed in addition to an algorithm to identify simultaneous events on the DNA and protein channels.

Results

The instrument was fully characterized, which included analysis of the data acquisition rate, sampling time, flow rate, detection efficiency, linear dynamic range, channel cross‐talk, and the limit of detection. Baculovirus samples were analyzed and the results were compared with concentrations obtained by a one‐channel flow cytometer and plaque assay.

Conclusions

The dual channel virus counter yields a representative value for the concentration of active viruses in an unpurified sample when compared with plaque assay and a one‐channel flow cytometer. The technique is rapid (within minutes), requires only minimal sample preparation and minimum sample size (∼100 μl). © 2005 Wiley‐Liss, Inc.
Expression and regulation of mouse SERDIN1, a highly conserved cardiac‐specific leucine‐rich repeat protein
Authors: Adameyko Igor I. , Mudry Ryan E. , Houston‐Cummings Nga Rewa M. , Veselov Alexander P. , Gregorio Carol C. , Tevosian Sergei G.
Published: April 2005

Despite recent progress, the precise mechanisms responsible for vertebrate cardiac development are still enigmatic. Better understanding of cardiac biology and disease necessitates identification and analysis of a full spectrum of regulatory and structural proteins specific to the developing heart. By performing an in silico screen, we identified a cardiac‐specific gene we named Serdin1. The Serdin1 gene is conserved, and the message is restricted to the heart in several vertebrate species, thus implicating Serdin1 as an important gene in cardiac development. In situ hybridization confirmed that the Serdin1 message is cardiac‐specific in mice as early as embryonic day 8.5. Antibody staining demonstrated predominantly nuclear staining in immortalized cardiac cell lines (P19 and HL‐1) and proliferating cultured cardiomyocytes, whereas in vivo SERDIN1 localizes to I bands of the sarcomere. Seven kilobases of the upstream regulatory sequence of Serdin1 is sufficient for cardiac‐specific expression. Computer analysis revealed an 80‐bp homologous region between the mouse and the human Serdin genes that contains GATA, SRF, and MEF sites. Cardiac specificity and localization patterns suggest that SERDIN1 is intimately integrated with the molecular pathways controlling cardiogenesis in vertebrates. Developmental Dynamics 233:540–552, 2005. © 2005 Wiley‐Liss, Inc.
Region‐specific expression of mario reveals pivotal function of the anterior nondigit region on digit formation in chick wing bud
Authors: Amano Takanori , Tamura Koji
Published: April 2005

We report the region‐specific expression of a novel gene, named mario, whose expression domain is in the distal tip of the presumptive and developing digit 2 region in the developing chick wing bud. The anterior region‐specific expression of mario corresponds well with the presence of digit 2, and fate map analysis showed that mario expression at early stages represents the presumptive digit 2 region. Using mario expression as a region‐specific marker for the digit 2 region, several surgical operations were performed to obtain insights into digit 2 development in the chick wing. Cell fate tracing concomitant with a zone of polarizing activity (ZPA) implantation revealed that an additional digit 2 in the ZPA implantation into the anterior or middle region of wing bud is derived from the original digit 2 region (mario‐positive region). Surgical manipulations revealed that the anterior nondigit region has an inhibitory effect on digit 2 formation. Taken together, these results suggest that the most‐anterior region, including the anterior necrotic zone, restricts the position of digit 2 region by limiting the anterior border of the digit 2 region and preventing its expansion. Developmental Dynamics 233:326–336, 2005. © 2005 Wiley‐Liss, Inc.
A nonlinear atomization model for computation of drop size distributions and spray simulations
Authors: Park Hongbok , Yoon Sam S. , Heister Stephen D.
Published: April 2005

A model has been developed to provide a comprehensive simulation of a spray formed by a high‐speed liquid jet. The primary atomization process is simulated in a completely nonlinear fashion using the boundary element method under the assumption of axisymmetric, inviscid flow. The presence of the orifice boundary layer is simulated with a ring vortex whose strength and location are uniquely determined from boundary layer properties at the orifice exit plane. Droplet and axisymmetric ligament tracking models have been developed to provide more comprehensive spray simulations. The breakup of the axisymmetric ligaments shed from the parent surface is assessed both in a nonlinear fashion as well as using the linear stability analysis of Ponstein. Using this latter approach, drop size distributions have been generated from first principles and compared with the popular Rosin–Rammler model. Copyright © 2005 John Wiley & Sons, Ltd.
An open study of risperidone liquid in the acute phase of schizophrenia
Authors: Yoshimura Reiji , Nakamura Jun , Shinkai Koji , Goto Makiko , Yamada Yasuhisa , Kaji Kyoko , Kakihara Shingo , Ueda Nobuhisa , Kohara Kimio , Ninomiya Hideaki , Egami Hideaki , Maeda Hisao
Published: April 2005

An open‐label study was performed to investigate the clinical efficacy and mechanisms of risperidone liquid in ameliorating positive symptoms in the acute phase of schizophrenia. Eighty‐eight patients (M/F: 50/38; age: 18–74 years;, mean±SD =32±16 years) meeting DSM‐IV criteria for schizophrenia and treated with risperidone liquid (14 patients also used lorazepam) were evaluated with regard to their clinical improvement and extrapyramidal side effects using the positive and negative syndrome scale (PANSS) and the Simpson and Angus scale (SAS), while plasma concentrations of HVA and MHPG were analysed by HPLC‐ECD before and 4 weeks after risperidone liquid administration. Patients showing a 50% or greater improvement in PANSS scores were defined as responders. An improvement in the PANSS scores related to excitement, hostility and poor impulse control was seen within 7 days after administration of risperidone liquid, and an improvement with regard to hallucinatory behaviour and uncooperativeness was seen within 14 days after its administration. Finally, 68% of patients were classified as responders 4 weeks after risperidone liquid administration. The scores of SAS were not changed after risperidone liquid administration. Pretreatment plasma homovanillic acid (HVA) levels in the responders (8.1±2.9 ng/ml) were higher than those in nonresponders (5.9±1.9 ng/ml). In addition, a negative correlation was seen between the changes in plasma HVA levels and the percentage of improvement in PANSS scores. On the other hand, there were no differences between pretreatment plasma 3‐methoxy‐4‐hydroxyphenylglycol (MHPG) levels and those of nonresponders. These results suggest that risperidone liquid is effective and well tolerated for the treatment of acute phase schizophrenic patients, and that efficacy is related to its affects on dopaminergic activity, not noradrenergic activity. Copyright © 2005 John Wiley & Sons, Ltd.