bluuebunny/crossref_metadata_2025 huggingface dataset:
Minimizing Instrumental Broadening of the Drop Size Distribution with the M-Fast-FSSP
Authors: Schmidt Sebastian , Lehmann Katrin , Wendisch Manfred
Published: January 2005

A modified version of the Fast-FSSP (the so-called M-Fast-FSSP) is introduced. It allows minimization of the instrumental broadening of measured cloud drop size distributions caused by laser beam inhomogeneities. This is achieved by applying a new technique based on a postexperiment stepwise reduction of the probe's sampling volume. For monodisperse glass bead samples it is shown that the width of the measured size distribution is considerably reduced when applying this technique, especially for large glass bead diameters. The instrumental broadening may exceed a factor of about 4 for a mean glass bead diameter of 30 μm. The M-Fast-FSSP was applied in two cloud measurement campaigns. For two specific cloud cases, the profile of the width of the measured drop size distribution changes significantly when applying the method.
Drugs and Tourists’ Experiences
Authors: Uriely Natan , Belhassen Yaniv
Published: January 2005

This study investigates the nature of drug-related tourist experiences from a phenomenological perspective. Based on 30 in-depth interviews with drug tourists and additional ethnographic data collected at various destinations of drug tourism, the empirical analysis yields four relevant insights: (1) drug-related tourist experiences are heterogeneous in nature and might involve either a pursuit of mere pleasure or a quest for profound and meaningful experiences; (2) for those who consume drugs for pleasure, the tourist experience is an intensified extension of their leisure routine; (3) the usage of drugs while traveling is not necessarily a form of escape from the reality of everyday life; and (4) the search for meaningful tourist experiences through drugs might involve the tourist’s attempt to engage in either “authentic” aspects of the local culture or drug-related subcultures.
Linking Wine Preferences to the Choice of Wine Tourism Destinations
Authors: Brown Graham , Getz Donald
Published: January 2005

This article explores the links between wine consumers’ preferences for wine from particular countries or regions and their interest in, and propensity to travel to, specific wine regions. Data from a convenience sample of 161 wine consumers in Calgary, Canada, revealed that specific appellation-of-origin preferences (e.g., for Australian or French wines) do have an influence on travel preferences and patterns. Nearly 70% of respondents preferred to drink wines from particular origins, and planned wine-related travel by respondents closely matched those geographic preferences. Other factors, however, were also shown to be important in shaping wine tourism destinations, including distance and cognitive factors. Implications are drawn for wine tourism marketing and for destination-choice theory. Recommendations are made for future research.
Methodological Considerations in Estimating the Gender Pay Gap for Employed Professionals
Authors: Morgan Laurie A. , Arthur Michelle M.
Published: January 2005

The authors address a methodological issue in estimating pay penalties to women professionals—whether the dependent variable in the pay equation should be hourly wage or earnings measured over some other period such as weeks, months, or a year. The authors analyze data on college graduates working in professional specialty occupations and on physicians, and they report two main conclusions. First, the appropriate specification of the pay equation for (employed) professionals is with ln(earnings) as the dependent variable with ln(hours) included as an independent variable. Second, the implications of using this specification for estimates of gender pay differentials are serious. In the data on professionals, respecification of the pay equation changes the estimate of the pay penalty to women from-4 6 to-7 6 percent. In the data on physicians, it changes the estimate from no penalty to a very large one, from-1 8 to-13 .0 percent.
Thickening the Frame: Cross-Theoretical Accounts of Contexts Inside and Around Technology
Authors: Pellegrino Giuseppina
Published: January 2005

Starting from the social construction of technology approach and proposing a literature review of the concept of technological frame, the distinction or continuity between contexts inside and around technology is analyzed as constitutive of a thicker frame. A multilayered articulation of the technological frame is proposed. Organizational history, identity, interorganizational relations, along with discursive practices and communicational routines are seen as the components of the intranet technological frame. Discursive practices, therefore, mediate between macro components belonging to the organizational dimension and micro components concerning the practice of specific organizational communities or workgroups and the inscribed patterns of use through which technology is temporarily stabilized into specific artifacts. The analysis of the frame as set of practices and contexts is carried out by referring to sociotechnical literature and findings of a completed Ph.D. dissertation about intranet technology.
Robotics-Driven Activities: Can They Improve Middle School Science Learning?
Authors: Robinson Mike
Published: January 2005

This study used case studies from three science teachers to compare three groups of students studying Grade 8 physics using Robolab instead of traditional lab materials. The three teachers represented an English as a second language class, a regular class with many English language learner students, and a Mathematics, Engineering, Science Achievement class of afterschool volunteer students. The teachers responded to nine questions regarding issues such as how robotics addresses the middle school physics standards, promotes inquiry learning and science literacy in students, increases applications and connection of science to everyday life, and provides the scaffolding for more discussion of everyday English and science academic language through the use of robotics materials and lab groups. The results indicated that robotics can promote inquiry, make physics more interesting, and help students learn and practice new words in English, among others.
Ellul and the Weather
Authors: Byrne John , Glover Leigh
Published: January 2005

Global climate change may result in a wide array of social and environmental harms, and this prospect has given rise to an international treaty, the 1992 UN Framework Convention on Climate Change. Scientific uncertainties, nation state politics, and economic resistance had to be addressed before this landmark environmental agreement could be realized. However, questions remain about the foundations and core commitments of this agreement. Ellul's characterology of technique is applied to the task of building a critique of the current international response to climate change and is allied to the proposition that ecological justice should guide the social response to climate change. It is argued that contemporary international efforts are directed at producing a “rational climate,” rather than a climate for ecological justice
Commodification of Ghana's Volta River: An Example of Ellul's Autonomy of Technique
Authors: Agbemabiese Lawrence , Byrne John
Published: January 2005

Jacques Ellul argued that modernity's nearly exclusive reliance on science and technology to design society would threaten hunan freedom. Of particular concern for Ellul was the prospect of the technical milieu overwhelming culture. The commodification of the Volta River in order to modernize Ghana illustrates the Ellulian dilemma of the autonomy of technique. Displacing a commons way of life, the Volta River Project has imposed an energy commodity regime and a technocratic management scheme to rule the basin, which now includes modern aluminum manufacturing. But after 50 years of modernization, there is little evidence of poverty alleviation or an advance of freedom.
Individual and Ecological Assets and Thriving Among African American Adolescent Male Gang and Community-Based Organization Members
Authors: Taylor Carl S. , Smith Pamela R. , Taylor Virgil A. , von Eye Alexander , Lerner Richard M. , Balsano Aida Bilalbegovic , Anderson Pamela M. , Banik Rumeli , Almerigi Jason B.
Published: January 2005

The third wave of the Overcoming the Odds longitudinal study involves data about individual and ecological developmental assets and thriving among African American male adolescents in inner-city Detroit gangs (N = 43) or in youth development, communitybased organizations (CBO; N = 50). Both groups had comparable levels of either low or high assets across the three waves. Stability in asset levels was not related to either of two measures of thriving or to a second measure of assets. The CBO youth had higher thriving and asset scores. More so for gang youth than CBO youth, there was evidence that asset and thriving scores were interrelated within this wave. Program and policy implications of these group differences are discussed.
Thriving in Adolescence
Authors: King Pamela Ebstyne , Dowling Elizabeth M. , Mueller Ross A. , White Krystal , Schultz William , Osborn Peter , Dickerson Everett , Bobek Deborah L. , Lerner Richard M. , Benson Peter L. , Scales Peter C.
Published: January 2005

This study assesses if correspondence existed between concepts scholars use to discuss positive youth development (PYD) and terms used by practitioners, parents, and youth to discuss exemplary PYD, or thriving. Qualitative and quantitative analyses of 173 interviews about the meaning of thriving found no significant commonality between the terms used in the scholarly literature and the specific words or phrases used by the adult and youth participants. However, the terms generated by the adults and youthwere able to be grouped into categories that reflect the general concepts used in the PYD literature (e.g., the five Cs ofcompetence, confidence, connection, character, caring, and the sixth C, contribution). Applications to public education youth programs are discussed.
Positive Youth Development, Participation in Community Youth Development Programs, and Community Contributions of Fifth-Grade Adolescents
Authors: Lerner Richard M. , Lerner Jacqueline V. , Almerigi Jason B. , Theokas Christina , Phelps Erin , Gestsdottir Steinunn , Naudeau Sophie , Jelicic Helena , Alberts Amy , Ma Lang , Smith Lisa M. , Bobek Deborah L. , Richman-Raphael David , Simpson Isla , Christiansen Elise DiDenti , von Eye Alexander
Published: January 2005

The 4-H Study of Positive Youth Development (PYD), a longitudinal investigation of a diverse sample of 1,700 fifth graders and 1,117 of their parents, tests developmental contextual ideas linking PYD, youth contributions, and participation in community youth development (YD) programs, representing a key ecological asset. Using data from Wave 1 of the study, structural equation modeling procedures provided evidence for five firstorder latent factors representing the “Five Cs” of PYD (competence, confidence, connection, character, and caring) and for their convergence on a second-order PYD latent construct. A theoretical construct, youth contribution, was also created and examined. Both PYD and YD program participation independently related to contribution. The importance of longitudinal analyses for extending the present results is discussed.
Burnt Orange
Authors: Hermes Joke
Published: January 2005

The Dutch tend to see themselves as a tolerant and antiracist nation, despite frequent evidence to the contrary. One area in cultural life that is both a site of stardom for nonwhite Dutch and a site of extreme racism and prejudice is popular sports and especially football (or soccer). Games played by the national soccer team are major events, in particular when the team comes near the finals in a European or world championship. In such cases, practices of television viewing run over into public social life and carnivalesque outbursts of sports loving and nationalist joy. This article will draw on interviews held with soccer fans that focused on nationalism and ethnicity. The author is interested in the pleasures of television sports viewing and football fandom, and in the representation of the male body (often signified in explicitly ethnic and racial terms) in television sports reporting as perceived by audiences.
The Frenzy of the Audible
Authors: Smith Jacob
Published: January 2005

The recorded laugh has been a potent index of authentic presence used to bridge the gap between recorded sound and listener. An analysis of the recorded genres of laughing songs and laughing stories shows that the phonographic laugh played an important role as a precursor to broadcast laugh track. Moving from these early phonographic examples, the pre-recorded laugh track is placed in the historical and discursive contexts of radio and television and their ideology of liveness. Throughout these different media contexts, the laugh has been presented as the ultimate expression of the human, and its mechanical reproduction serves as a lightning rod for anxieties concerning authenticity and the social dimensions of mass media consumption.
Sphingosine kinase-1 enhances endothelial cell survival through a PECAM-1–dependent activation of PI-3K/Akt and regulation of Bcl-2 family members
Authors: Limaye Vidya , Li Xiaochun , Hahn Chris , Xia Pu , Berndt Michael C. , Vadas Mathew A. , Gamble Jennifer R.
Published: January 2005

Sphingosine-1-phosphate (S1P), the bioactive product of sphingosine kinase (SK) activation, is a survival factor for endothelial cells. The mechanism of SK-mediated survival was investigated in endothelial cells with moderately raised intracellular SK activity. Overexpression of SK mediated survival primarily through the activation of the phosphatidyl inositol 3-kinase (PI-3K)/protein kinase B (Akt/PKB) pathway and an associated up-regulation of the antiapoptotic protein B cell lymphoma gene 2 (Bcl-2) and down-regulation of the proapoptotic protein bisindolylmaleimide (Bcl-2 interacting mediator of cell death; Bim). In addition there was an up-regulation and dephosphorylation of the junctional molecule platelet endothelial cell adhesion molecule-1 (PECAM-1), which was obligatory for activation of the PI-3K/Akt pathway, for SK-induced cell survival, and for the changes in the apoptosis-related proteins. Thus, raised intracellular SK activity induced a molecule involved in cell–cell interactions to augment cell survival through a PI-3K/Akt–dependent pathway. This is distinct from the activation of both PI-3K/Akt and mitogen-activated protein kinase (MAPK) pathways seen with exogenously added S1P. Cells overexpressing SK showed enhanced survival under conditions of serum deprivation and absence of attachment to extracellular matrix, suggesting a role for SK in the regulation of vascular phenomena that occur under conditions of stress, such as angiogenesis and survival in unattached states, as would be required for a circulating endothelial cell.
Fibrinogen Philadelphia, a hypodysfibrinogenemia characterized by abnormal polymerization and fibrinogen hypercatabolism due to γ S378P mutation
Authors: Keller Margaret A. , Martinez Josè , Baradet Timothy C. , Nagaswami Chandrasekaran , Chernysh Irina N. , Borowski Meggin K. , Surrey Saul , Weisel John W.
Published: January 2005

Fibrinogen Philadelphia, a hypodysfibrinogenemia described in a family with a history of bleeding, is characterized by prolonged thrombin time, abnormal fibrin polymerization, and increased catabolism of the abnormal fibrinogen. Turbidity studies of polymerization of purified fibrinogen under different ionic conditions reveal a reduced lag period and lower final turbidity, indicating more rapid initial polymerization and impaired lateral aggregation. Consistent with this, scanning and transmission electron microscopy show fibers with substantially lower average fiber diameters. DNA sequence analysis of the fibrinogen genes A, B, and G revealed a T>C transition in exon 9 resulting in a serine-to-proline substitution near the γ chain C-terminus (S378P). The S378P mutation is associated with fibrinogen Philadelphia in this kindred and was not found in 10 controls. This region of the γ chain is involved in fibrin polymerization, supporting this as the polymerization defect causing the mutation. Thus, this abnormal fibrinogen is characterized by 2 unique features: (1) abnormal polymerization probably due to a major defect in lateral aggregation and (2) hypercatabolism of the mutant protein. The location, nature, and unusual characteristics of this mutation may add to our understanding of fibrinogen protein interactions necessary for normal catabolism and fibrin formation.
Sema4D induces angiogenesis through Met recruitment by Plexin B1
Authors: Conrotto Paolo , Valdembri Donatella , Corso Simona , Serini Guido , Tamagnone Luca , Comoglio Paolo Maria , Bussolino Federico , Giordano Silvia
Published: January 2005

Semaphorins, a large family of membrane-bound and secreted proteins, signal through their transmembrane receptors, the plexins. Semaphorins and plexins share structural homologies with scatter factor receptors, a family of tyrosine kinase receptors for which Met is the prototype. Semaphorins have been studied primarily in the developing nervous system, where they act as repelling cues in axon guidance. However, they are widely expressed in several tissues, and their role in epithelial morphogenesis has been recently established. Not much is known about their role in angiogenesis, a key step during embryonic development and adulthood. Here we demonstrate that a semaphorin, Sema4D, is angiogenic in vitro and in vivo and that this effect is mediated by its high-affinity receptor, Plexin B1. Moreover, we prove that biologic effects elicited by Plexin B1 require coupling and activation of the Met tyrosine kinase. In sum, we identify a proangiogenic semaphorin and provide insight about the signaling machinery exploited by Plexin B1 to control angiogenesis.
Prognostic Index for Adult Patients With Acute Myeloid Leukemia in First Relapse
Authors: Breems Dimitri A. , Van Putten Wim L.J. , Huijgens Peter C. , Ossenkoppele Gert J. , Verhoef Gregor E.G. , Verdonck Leo F. , Vellenga Edo , De Greef Georgine E. , Jacky Emanuel , Van der Lelie Johannes , Boogaerts Marc A. , Löwenberg Bob
Published: January 2005

Purpose

The treatment of acute myeloid leukemia (AML) in first relapse is associated with unsatisfactory rates of complete responses that usually are short lived. Therefore, a clinically useful prognostic index can facilitate therapeutic decision making and evaluation of investigational treatment strategies at relapse of AML.

Patients and Methods

A prognostic score is presented based on the multivariate analysis of 667 AML patients in first relapse among 1,540 newly diagnosed non-M3 AML patients (age 15 to 60 years) entered onto three successive Dutch-Belgian Hemato-Oncology Cooperative Group and the Swiss Group for Clinical Cancer Research Collaborative Group trials.

Results

Four clinically relevant parameters are included in this index (ie, length of relapse-free interval after first complete remission, cytogenetics at diagnosis, age at relapse, and whether previous stem-cell transplantation was performed). Using this stratification system, three risk groups were defined: a favorable prognostic group A (overall survival [OS] of 70% at 1 year and 46% at 5 years), an intermediate-risk group B (OS of 49% at 1 year and 18% at 5 years), and a poor-risk group C (OS of 16% at 1 year and 4% at 5 years).

Conclusion

The prognostic index estimates the outcome of AML patients in first relapse using four commonly applied clinical parameters and might identify patients who are candidates for salvage and investigational therapy.
Hoxa2 downregulates Six2 in the neural crest-derived mesenchyme
Authors: Kutejova Eva , Engist Bettina , Mallo Moisés , Kanzler Benoît , Bobola Nicoletta
Published: January 2005

The Hoxa2 transcription factor acts during development of the second branchial arch. As for most of the developmental processes controlled by Hox proteins, the mechanism by which Hoxa2 regulates the morphology of second branchial arch derivatives is unclear. We show that Six2, another transcription factor, is genetically downstream of Hoxa2. High levels of Six2 are observed in the Hoxa2 loss-of-function mutant. By using a transgenic approach to overexpress Six2 in the embryonic area controlled by Hoxa2, we observed a phenotype that is reminiscent of the Hoxa2 mutant phenotype. Furthermore, we demonstrate that Hoxa2 regulation of Six2 is confined to a 0.9 kb fragment of the Six2 promoter and that Hoxa2 binds to this promoter region. These results strongly suggest that Six2 is a direct target of Hoxa2.
Elastin-derived peptides enhance angiogenesis by promoting endothelial cell migration and tubulogenesis through upregulation of MT1-MMP
Authors: Robinet Arnaud , Fahem Abdel , Cauchard Jean-Hubert , Huet Eric , Vincent Loïc , Lorimier Sandrine , Antonicelli Franck , Soria Claudine , Crepin Michel , Hornebeck William , Bellon Georges
Published: January 2005

Elastin-derived peptides display a wide range of biological activities in a number of normal and transformed cells but their involvement in angiogenesis has not been reported. In the present study, we show that κ-elastin and VGVAPG hexapeptide elastin motif accelerated angiogenesis in the chick chorio-allantoic membrane in an in vivo model. They also stimulated pseudotube formation from human vascular and microvascular endothelial cells in the matrigel and collagen models as well as cell migration in an in vitro wound healing assay. Confocal and scanning electron microscopy analyses revealed the main reorganization of actin filaments mediated by elastin-derived peptides and changes in cell shape that correlated with a decrease of the cell form factor determined by computerized image analysis. Such elastin-derived peptide effects were attributed to upregulation of proMT1-MMP and proMMP-2 expression and activation at both the mRNA and protein levels. Batimastat, an inhibitor of furin convertase and TIMP-2, but not TIMP-1, totally abolished the influence of elastin-derived peptides (EDPs) on cell migration and tubulogenesis, thus favoring the involvement of MT1-MMP in such processes. To assess its contribution to EDP-mediated angiogenesis further, we used a small interfering RNA (siRNA) approach for specifically silencing MT1-MMP in human microvascular endothelial cells. Four sets of 21 bp siRNA duplexes targeting MT1-MMP mRNA were synthesized by in vitro transcription. Two of them proved to inhibit MT1-MMP expression efficiently but did not affect MT2-, MT3- and MT5-MMP expression. Seventy-two hours after transfection with 25 nM siRNAs EDP-induced MT1-MMP expression at the mRNA and protein levels was decreased fourfold. In parallel, proMMP-2 activation was inhibited. A scrambled siRNA, used as a negative control, had no effect. Finally, the effect of elastin peptides on pseudotube formation in MT1-MMP-siRNA transfected cells was totally abolished. These data emphasise the crucial role of MT1-MMP in the elastin-induced angiogenic phenotype of endothelial cells.
Biosonar performance of foraging beaked whales (Mesoplodon densirostris)
Authors: Madsen P. T. , Johnson M. , de Soto N. Aguilar , Zimmer W. M. X. , Tyack P.
Published: January 2005

Toothed whales (Cetacea, odontoceti) emit sound pulses to probe their surroundings by active echolocation. Non-invasive, acoustic Dtags were placed on deep-diving Blainville's beaked whales (Mesoplodon densirostris) to record their ultrasonic clicks and the returning echoes from prey items, providing a unique view on how a whale operates its biosonar during foraging in the wild. The process of echolocation during prey capture in this species can be divided into search, approach and terminal phases, as in echolocating bats. The approach phase, defined by the onset of detectable echoes recorded on the tag for click sequences terminated by a buzz, has interclick intervals (ICI) of 300-400 ms. These ICIs are more than a magnitude longer than the decreasing two-way travel time to the targets, showing that ICIs are not given by the two-way-travel times plus a fixed, short lag time. During the approach phase, the received echo energy increases by 10.4(±2) dB when the target range is halved, demonstrating that the whales do not employ range-compensating gain control of the transmitter, as has been implicated for some bats and dolphins. The terminal/buzz phase with ICIs of around 10 ms is initiated when one or more targets are within approximately a body length of the whale (2-5 m), so that strong echo returns in the approach phase are traded for rapid updates in the terminal phase. It is suggested that stable ICIs in the search and approach phases facilitate auditory scene analysis in a complex multi-target environment, and that a concomitant low click rate allows the whales to maintain high sound pressure outputs for prey detection and discrimination with a pneumatically driven,bi-modal sound generator.
Body-induced vortical flows: a common mechanism for self-corrective trimming control in boxfishes
Authors: Bartol Ian K. , Gharib Morteza , Webb Paul W. , Weihs Daniel , Gordon Malcolm S.
Published: January 2005

Boxfishes (Teleostei: Ostraciidae) are marine fishes having rigid carapaces that vary significantly among taxa in their shapes and structural ornamentation. We showed previously that the keels of the carapace of one species of tropical boxfish, the smooth trunkfish, produce leading edge vortices (LEVs) capable of generating self-correcting trimming forces during swimming. In this paper we show that other tropical boxfishes with different carapace shapes have similar capabilities. We conducted a quantitative study of flows around the carapaces of three morphologically distinct boxfishes(spotted boxfish, scrawled cowfish and buffalo trunkfish) using stereolithographic models and three separate but interrelated analytical approaches: digital particle image velocimetry (DPIV), pressure distribution measurements, and force balance measurements. The ventral keels of all three forms produced LEVs that grew in circulation along the bodies, resembling the LEVs produced around delta-winged aircraft. These spiral vortices formed above the keels and increased in circulation as pitch angle became more positive,and formed below the keels and increased in circulation as pitch angle became more negative. Vortices also formed along the eye ridges of all boxfishes. In the spotted boxfish, which is largely trapezoidal in cross section, consistent dorsal vortex growth posterior to the eye ridge was also present. When all three boxfishes were positioned at various yaw angles, regions of strongest concentrated vorticity formed in far-field locations of the carapace compared with near-field areas, and vortex circulation was greatest posterior to the center of mass. In general, regions of localized low pressure correlated well with regions of attached, concentrated vorticity, especially around the ventral keels. Although other features of the carapace also affect flow patterns and pressure distributions in different ways, the integrated effects of the flows were consistent for all forms: they produce trimming self-correcting forces, which we measured directly using the force balance. These data together with previous work on smooth trunkfish indicate that body-induced vortical flows are a common mechanism that is probably significant for trim control in all species of tropical boxfishes.
Non-olfactory chemoreceptors in asymmetric setae activate antennular grooming behavior in the Caribbean spiny lobsterPanulirus argus
Authors: Schmidt Manfred , Derby Charles D.
Published: January 2005

In the spiny lobster Panulirus argus the antennules carrying olfactory sensilla called aesthetascs and several types of other non-olfactory sensilla accompanying them are frequently groomed by the third maxillipeds in a stereotyped behavioral pattern. This behavior can be elicited by chemical stimulation with l-glutamate. Using selective sensillar ablations,we tested whether this behavior is driven by the numerous aesthetascs, which have been implicated as mediating this chemically elicited antennular grooming behavior in a previous investigation, or other, less numerous sensilla called asymmetric setae, which are tightly associated with aesthetascs. The selective sensilla ablations showed that the asymmetric setae are necessary and sufficient for driving chemically elicited antennular grooming. Bilateral elimination of the ca. 160 asymmetric setae almost completely abolished the behavior, whereas bilateral elimination of the ca. 2600 aesthetascs or of another type of sensilla associated with them (guard setae) did not cause a reduction in chemically elicited antennular grooming. Microscopical analysis of the morphological properties of the asymmetric setae revealed the presence of a terminal pore at the tip of the seta and a phalloidin-positive scolopale below its base. Since these structures have been identified in decapod crustaceans as modality-specific structures of bimodal chemo- and mechanosensory sensilla, we conclude that the asymmetric setae belong to this type of sensilla and thus have the appropriate features to function as chemoreceptors in the elicitation of antennular grooming. The identification of asymmetric setae and not aesthetascs as the drivers of chemically elicited antennular grooming suggests that it is not the olfactory pathway in the brain but a parallel pathway, constituted mainly by the lateral antennular neuropils, that is the neuronal substrate of this behavior. The lateral antennular neuropils receive non-olfactory sensory input from the antennule and contain the major arborizations of antennular motoneurons, allowing that direct sensory-motor coupling is involved in mediating the chemical elicitation of antennular grooming behavior.
Dynamic pressure maps for wings and tails of pigeons in slow, flapping flight, and their energetic implications
Authors: Usherwood James R. , Hedrick Tyson L. , McGowan Craig P. , Biewener Andrew A.
Published: January 2005

Differential pressure measurements offer a new approach for studying the aerodynamics of bird flight. Measurements from differential pressure sensors are combined to form a dynamic pressure map for eight sites along and across the wings, and for two sites across the tail, of pigeons flying between two perches. The confounding influence of acceleration on the pressure signals is shown to be small for both wings and tail. The mean differential pressure for the tail during steady, level flight was 25.6 Pa, which, given an angle of attack for the tail of 47.6°, suggests the tail contributes 7.91% of the force required for weight support, and requires a muscle-mass specific power of 19.3 W kg-1 for flight to overcome its drag at 4.46 m s-1. Differential pressures during downstroke increase along the wing length, to 300-400 Pa during take-off and landing for distal sites. Taking the signals obtained from five sensors sited along the wing at feather bases as representative of the mean pressure for five spanwise elements at each point in time, and assuming aerodynamic forces act within the x-z plane (i.e. no forces in the direction of travel) and perpendicular to the wing during downstroke, we calculate that 74.5% of the force required to support weight was provided by the wings, and that the aerodynamic muscle-mass specific power required to flap the wings was 272.7 W kg-1.
Electrical activity of caudal neurosecretory neurons in seawater and freshwater-adapted Platichthys flesus, in vivo
Authors: Ashworth A. J. , Banks J. R. , Brierley M. J. , Balment R. J. , McCrohan C. R.
Published: January 2005

This study examined the electrical firing activity of neuroendocrine Dahlgren cells in the caudal neurosecretory system (CNSS) of the euryhaline flounder in vivo. Intracellular recordings revealed generally similar activity patterns and membrane properties to those previously reported in vitro. To investigate the potential role of the CNSS in osmoregulatory adaptation, extracellular, multiunit, recordings compared the activity patterns of Dahlgren cells in fully seawater- and freshwater-adapted fish. The proportion of cells showing bursting (as opposed to phasic or tonic) activity was greater in seawater-than in freshwater-adapted fish, as was the Correlation Index, a measure of the degree of correlation between firing activities of cells recorded simultaneously from the same preparation. Acute transfer of fish from seawater to freshwater gill perfusion led to recruitment of previously silent Dahlgren cells and a reduction in Correlation Index;freshwater to seawater transfer increased the Correlation Index. Severing the spinal cord anterior to the CNSS led to an increase in overall Dahlgren cell activity. Electrical stimulation of branchial nerve branches providing input to the brainstem, or tactile (pinch) stimulation of lips or fins, led to a reduction in CNSS activity lasting up to 500 s, indicating the presence of descending modulatory pathways from the brain. These results are consistent with a role for CNSS neuropeptides, urotensins, in supporting survival in a hypertonic, seawater, environment.
Troponin T expression in trout red muscle correlates with muscle activation
Authors: Coughlin David J. , Caputo Nicholas D. , Bohnert Krista L. , Weaver Frances E.
Published: January 2005

Red or aerobic muscle from the anterior of rainbow trout Oncorhynchus mykiss activates (generates force) more quickly than that from the posterior. TnT is a component of the troponin complex that modulates muscle activation once Ca2+ is bound. Since trout express at least two forms of TnT in their red muscle (S1 and S2), the differential expression of these two forms was predicted to explain variations in contractile properties. TnT isoforms from trout muscle were identified through hydroxy-apatite chromatography of purified myofibrillar proteins followed by SDS-PAGE. Western blots employing a mammalian anti-troponin T monoclonal antibody were used to identify TnT isoforms. The relative expression of the two isoforms of TnT was then examined at seven longitudinal positions from each of three fish using SDS-PAGE and densitometry on the silver-stained TnT bands. A significant shift in expression was detected from anterior to posterior in all three fish with TnT S1 becoming more dominant in the posterior red muscle. As predicted, a shift in TnT expression was associated with the decrease in activation rate along the length of the fish. This study was then extended to include a different species of salmonid, brook trout Salvelinus fontinalis, to explore the generality of TnT modulation of muscle activation. Muscle contractile properties were determined from anterior and posterior muscle, and relative expression of S1 and S2 was determined. Unlike rainbow trout, there is no consistent longitudinal pattern of muscle activation in brook trout:some fish have kinetically faster muscle in the anterior, some in the posterior. Similarly, there is no consistent pattern of TnT expression. Individual analysis of muscle activation and TnT expression in brook trout provides insight into the role of TnT in modulating muscle activation in slow fish muscle.
Regulation of branchial V-H+-ATPase,Na+/K+-ATPase and NHE2 in response to acid and base infusions in the Pacific spiny dogfish (Squalus acanthias)
Authors: Tresguerres Martin , Katoh Fumi , Fenton Heather , Jasinska Edyta , Goss Greg G.
Published: January 2005

To study the mechanisms of branchial acid-base regulation, Pacific spiny dogfish were infused intravenously for 24 h with either HCl (495± 79μmol kg-1 h-1) or NaHCO3 (981±235μmol kg-1 h-1). Infusion of HCl produced a transient reduction in blood pH. Despite continued infusion of acid, pH returned to normal by 12 h. Infusion of NaHCO3 resulted in a new steady-state acid-base status at ∼0.3 pH units higher than the controls. Immunostained serial sections of gill revealed the presence of separate vacuolar proton ATPase (V-H+-ATPase)-rich or sodium-potassium ATPase(Na+/K+-ATPase)-rich cells in all fish examined. A minority of the cells also labeled positive for both transporters. Gill cell membranes prepared from NaHCO3-infused fish showed significant increases in both V-H+-ATPase abundance (300±81%) and activity. In addition, we found that V-H+-ATPase subcellular localization was mainly cytoplasmic in control and HCl-infused fish, while NaHCO3-infused fish demonstrated a distinctly basolateral staining pattern. Western analysis in gill membranes from HCl-infused fish also revealed increased abundance of Na+/H+ exchanger 2(213±5%) and Na+/K+-ATPase (315±88%)compared to the control.
Redox signaling in colonial hydroids: many pathways for peroxide
Authors: Blackstone Neil W. , Bivins Matthew J. , Cherry Kimberly S. , Fletcher Robert E. , Geddes Gabrielle C.
Published: January 2005

Studies of mitochondrial redox signaling predict that the colonial hydroids Eirene viridula and Podocoryna carnea should respond to manipulations of reactive oxygen species (ROS). Both species encrust surfaces with feeding polyps connected by networks of stolons; P. carnea is more `sheet-like' with closely spaced polyps and short stolons, while E. viridula is more `runner-like' with widely spaced polyps and long stolons. Treatment with the chemical antioxidant vitamin C diminishes ROS in mitochondrion-rich epitheliomuscular cells (EMCs) and produces phenotypic effects (sheet-like growth) similar to uncouplers of oxidative phosphorylation. In peripheral stolon tips, treatment with vitamin C triggers a dramatic increase of ROS that is followed by tissue death and stolon regression. The enzymatic anti-oxidant catalase is probably not taken up by the colony but, rather, converts hydrogen peroxide in the medium to water and oxygen. Exogenous catalase does not affect ROS in mitochondrion-rich EMCs, but does increase the amounts of ROS emitted from peripheral stolons, resulting in rapid, runner-like growth. Treatment with exogenous hydrogen peroxide increases ROS levels in stolon tips and results in somewhat faster colony growth. Finally, untreated colonies of E. viridula exhibit higher levels of ROS in stolon tips than untreated colonies of P. carnea. ROS may participate in a number of putative signaling pathways: (1) high levels of ROS may trigger cell and tissue death in peripheral stolon tips; (2)more moderate levels of ROS in stolon tips may trigger outward growth, inhibit branching and, possibly, mediate the redox signaling of mitochondrion-rich EMCs; and (3) ROS may have an extra-colony function, perhaps in suppressing the growth of bacteria.
Development of the respiratory response to hypoxia in the isolated brainstem of the bullfrogRana catesbeiana
Authors: Winmill Rachel E. , Chen Anna K. , Hedrick Michael S.
Published: January 2005

The aim of this study was to examine the effects of cellular hypoxia, and the contribution of anaerobic metabolism, on respiratory activity in bullfrogs at different stages of development. Respiratory-related neural activity was recorded from cranial nerve rootlets in isolated brainstem preparations from pre-metamorphic (Taylor–Köllros (T-K) stages VIII-XVI) and postmetamorphic tadpoles (T-K stages XXIV-XXV) and adults. Changes in fictive gill/lung activity in brainstems from pre-metamorphic tadpoles and lung activity in postmetamorphic tadpoles and adults were examined during superfusion with control (98% O2/2% CO2) or hypoxic (98%N2/2% CO2) artificial cerebrospinal fluid (aCSF). Iodoacetate (IAA; 100 μmol l–1) was used in conjunction with hypoxic aCSF to inhibit glycolysis. Gill burst frequency in pre-metamorphic brainstems did not change over a 3 h exposure to hypoxia and fictive lung burst frequency slowed significantly, but only after 3 h hypoxia. Blockade of glycolysis with IAA during hypoxia significantly reduced the time respiratory activity could be maintained in pre-metamorphic, but not in adult,brainstems. In brainstems from post-metamorphic tadpoles and adults, lung burst frequency became significantly more episodic within 5–15 min hypoxic exposure, but respiratory neural activity was subsequently abolished in every preparation. The cessation of fictive breathing was restored to control levels upon reoxygenation. Neither tadpole nor adult brainstems exhibited changes in neural bursts resembling `gasping' that is observed in mammalian brainstems exposed to severe hypoxia. There was also a significant increase in the frequency of `non-respiratory' bursts in hypoxic postmetamorphic and adult brainstems, but not in pre-metamorphic brainstems. These results indicate that pre-metamorphic tadpoles are capable of maintaining respiratory activity for 3 h or more during severe hypoxia and rely to a great extent upon anaerobic metabolism to maintain respiratory motor output. Upon metamorphosis, however, hypoxia results in significant changes in respiratory frequency and pattern, including increased lung burst episodes,non-ventilatory bursts and a reversible cessation of respiratory activity. Adults have little or no ability to maintain respiratory activity through glycolysis but, instead, stop respiratory activity until oxygen is available. This `switch' in the respiratory response to hypoxia coincides morphologically with the loss of gills and obligate air-breathing in the postmetamorphic frog. We hypothesize that the cessation of respiratory activity in post-metamorphic tadpoles and adults is an adaptive, energy-saving response to low oxygen.
3H-l-histidine and 65Zn2+ are cotransported by a dipeptide transport system in intestine of lobsterHomarus americanus
Authors: Conrad Erik M. , Ahearn Gregory A.
Published: January 2005

The tubular intestine of the American lobster Homarus americanuswas isolated in vitro and perfused with a physiological saline whose composition was based on hemolymph ion concentrations and contained variable concentrations of 3H-l-histidine, 3H-glycyl-sarcosine and 65Zn2+. Mucosa to serosa (M→S) flux of each radiolabelled substrate was measured by the rate of isotope appearance in the physiological saline bathing the tissue on the serosal surface. Addition of 1–50 μmol l–1 zinc to the luminal solution containing 1–50 μmol l–13H-l-histidine significantly (P<0.01)increased M→S flux of amino acid compared to controls lacking the metal. The kinetics of M→S 3H-l-histidine flux in the absence of zinc followed Michaelis–Menten kinetics(Km=6.2±0.8 μmol l–1; Jmax =0.09±0.004 pmol cm–2min–1). Addition of 20 μmol l–1 zinc to the luminal perfusate increased both kinetic constants(Km=19±3 μmol l–1; Jmax=0.28±0.02 pmol cm–2min–1). Addition of both 20 μmol l–1 zinc and 100 μmol l–1l-leucine abolished the stimulatory effect of the metal alone (Km=4.5±1.7μmol l–1; Jmax=0.08±0.008 pmol cm–2 min–1). In the absence of l-histidine, M→S flux of 65Zn2+ also followed the Michaelis–Menten relationship and addition of l-histidine to the perfusate significantly (P<0.01)increased both kinetic constants. Addition of either 50 μmol l–1 Cu+ or Cu2+ and 20 μmol l–1l-histidine simultaneously abolished the stimulatory effect of l-histidine alone on transmural 65Zn2+ transport. Zinc-stimulation of M→S 3H-l-histidine flux was significantly(P<0.01) reduced by the addition of 100 μmol l–1 glycyl-sarcosine to the perfusate, as a result of the dipeptide significantly (P<0.01) reducing both l-histidine transport Km and Jmax. Transmural transport of 3H-glycyl-sarcosine was unaffected by the presence of either l-histidine or l-leucine when either amino acid was added to the perfusate alone, but at least a 50% reduction in peptide transport was observed when zinc and either of the amino acids were added simultaneously. These results show that 3H-l-histidine and 65Zn2+ are cotransported across the lobster intestine by a dipeptide carrier protein that binds both substrates in a bis-complex (Zn-[His]2) resembling the normal dipeptide substrate. In addition, the transmural transports of both substrates may also occur by uncharacterized carrier processes that are independent of one another and appear relatively specific to the solutes used in this study.
The influence of environmentalPO2 on hemoglobin oxygen saturation in developing zebrafishDanio rerio
Authors: Grillitsch Sandra , Medgyesy Nikolaus , Schwerte Thorsten , Pelster Bernd
Published: January 2005

Several studies suggest that during early larval development of lower vertebrates convective blood flow is not essential to supply oxygen to the tissues, but information about the oxygenation status of larvae during the time of cutaneous respiration is still missing. If convective oxygen transport contributes to the oxygen supply to tissues, venous blood in the central circulatory system should be partly deoxygenated, and hyperoxia should increase the oxygen saturation of the hemoglobin. To analyze the changes in hemoglobin oxygen saturation induced by hyperoxic incubation, zebrafish larvae were incubated in a tiny chamber between polytetrafluoroethylene membranes(Teflon), so that the oxygen supply could be rapidly modified. Hemoglobin oxygen saturation was measured in vivo by combining video imaging techniques with a spectrophotometrical analysis of hemoglobin light absorption at specific wavelengths for maximal absorption of oxygenated and deoxygenated blood (413 nm and 431 nm, respectively) under normoxic conditions and after a 10 min period of hyperoxia (PO2=100 kPa),assuming that at a PO2 of 100 kPa the hemoglobin is fully saturated. The results demonstrated that red blood cell oxygenation of zebrafish larvae at 4 days post fertilization (d.p.f.), 5 d.p.f. and 12 d.p.f. could be increased by hyperoxia. The data suggest that at the time of yolk sac degradation (i.e. 4 d.p.f. and 5 d.p.f.), when the total surface area of the animal is reduced, bulk diffusion of oxygen may not be sufficient to prevent a partial deoxygenation of the hemoglobin. The decrease in hemoglobin oxygenation observed at 12 d.p.f. confirms earlier studies indicating that at 12–14 d.p.f., convective oxygen transport becomes necessary to ensure oxygen supply to the growing tissues.
Selective Extraction of Silver Ion with Proton-Switchable Calix[4]arene
Authors: Higuchi Hirotaka , Matsufuji Takashi , Oshima Tatsuya , Ohto Keisuke , Inoue Katsutoshi , Tsend-Ayush Tsermaa , Gloe Karsten
Published: January 2005

New pyridine-functionalized proton-switchable calix[4]arenes were synthesized to investigate extraction properties, and performed good extractability toward silver ion in acidic solution.
Moxifloxacin—Warfarin Interaction: A Series of Five Case Reports
Authors: Elbe Dean HT , Chang Sandra W
Published: January 2005

OBJECTIVE:

To report 5 cases of a moxifloxacin—warfarin drug interaction, all resulting in elevated international normalized ratios (INRs) and clinically significant hemorrhage in one case.

CASE SUMMARIES:

Between January 2002 and January 2004, 4 men and 1 woman (age range 63–92 y) were retrospectively identified as having significantly elevated INR results shortly after being prescribed moxifloxacin with concomitant warfarin therapy.

DISCUSSION:

This is the second series of case reports describing an interaction between warfarin and moxifloxacin. The current moxifloxacin product monograph indicates this drug has no significant effect on the pharmacokinetics of R- or S-warfarin or the prothrombin time (INR). A moxifloxacin—warfarin interaction probably led to prolonged hospitalization in 2 cases and significant gastrointestinal hemorrhage in one case. In 3 of the 5 cases, a moxifloxacin—warfarin interaction was assessed as probable, and in the remaining 2 cases, a moxifloxacin—warfarin interaction was assessed as possible by use of the Naranjo probability scale.

CONCLUSIONS:

Healthcare professionals should consider moxifloxacin for the potential to interact with warfarin. Routine, frequent INR monitoring for patients previously stabilized on warfarin during initiation and discontinuation of moxifloxacin may help detect this potential interaction.