bluuebunny/crossref_metadata_2025 huggingface dataset:
A solid solution series between xenotime (YtPO4) and chernovite (YtAsO4)
Authors: Graeser Stefan , Schwander Hans , Stalder Hans A.
Published: December 2006

The mineral chernovite, described as a new mineral from the Urals by Russian mineralogists in 1967 (Goldin et al, 1967), has been found at three different localities in mineral fissures in the Binnatal, Switzerland, and a little to the south, in Italy. The mineral occurs in greenish-yellow bipyramidal crystals up to about I mm. A detailed single-crystal study of several specimens showed that the lattice constants vary considerably on either side of those published for the original chernovite. The refractive indices, too, display some variation. Microprobe analyses of this material, and of xenotime specimens from the same region, revealed that there exists at least partial solution between chernovite and xenotime. The three chernovite samples have molar percentages of 63·2, 73·2, and 82·0 % YtAsO4 (the Urals chernovite has about 95·2 %). These studies prove the existence of an isomorphous series between xenotime and chernovite, at least in the As-rich portion.
On the metamorphic facies of the Dahomeyan gneiss in the western Accra Plains, Ghana
Authors: Holm Richard F.
Published: December 2006

In the Dahomeyan of the western Accra Plains mafie gneisses, amphibolites, and ortho-amphibolite dykes in granitic gneiss occur. During the latest recrystallization, metamorphic conditions ranged (north to south) from oligoclase-epidote amphibolite subfacies through andesine-epidote amphibolite subfacies to at least the medium or upper part of the amphibolite facies. Chemical analyses of hornblende, garnet, and clinopyroxene from two mafic gneiss specimens supplement data from the Mampong specimen (Knorring and Kennedy, 1958) and indicate that mineral compositions are largely controlled by rock compositions.
Lithium–aluminium micas from the Meldon aplite, Devonshire, England
Authors: Nawaz Chaudhry M. , Howie R. A.
Published: December 2006

Chemical analyses of sixteen lithium-aluminium micas are presented along with their optical, physical, and X-ray data. Compositional variation, substitution relations in structural positions, and octahedral occupancy are discussed. The 2M2 structural types are found to crystallize in volatilerich low-temperature environments whereas the 1M polytypes occur in comparatively volatile-poor and higher-temperature environments. Variation diagrams have been constructed to show the relationship between octahedral sites occupied by and refractive indices and specific gravities.
The geochemistry of the Devonian lavas of the northern Lorne Plateau, Scotland
Authors: Groome D. R. , Hall A.
Published: December 2006

Chemical analyses of the Lorne volcanic rocks show that the basalts and andesites are a closely related suite of lavas, notably rich in alkalis, especially potassium. The rhyolites of the Lorne area do not appear to form a continuous series with the more basic rocks. The various lava types are compared with the plutonic rocks of the area, and a relationship is suggested between the basic lavas and appinitic intrusions. The acid lavas are not comparable to granites in the area.

The late orogenic igneous activity in this part of the Caledonides therefore appears to involve three generations of magma, produced separately but within a short time of one another. The assumption that all the late Caledonian igneous rocks of the Scottish Highlands are differentiates of a common parent magma is not justified.
Supercooling and the crystallization of plagioclase from a basaltic magma
Authors: Gibb Fergus G. F.
Published: December 2006

The liquidus temperature (1198 °C) and equilibrium phase relations of a sample of Columbia River basalt from the Picture Gorge section have been determined at I atmosphere by heating in a controlled atmosphere. When this basalt is cooled from above its liquidus temperature the liquidus phase (plagioclase) may fail to crystallize depending on the degree of undercooling and the duration of the experiment. A field in temperature-time space in which plagioclase fails to crystallize on cooling is separated from another in which plagioclase always crystallizes by a third in which the nucleation of plagioclase is unpredictable in terms of temperature and time. The extent to which this basaltic liquid can be supercooled without the crystallization of plagioclase is independent of the time it is held above the liquidus or the temperature in excess of the liquidus to which it is heated.

The exceptionally long times required to ensure the nucleation of plagioclase at or near the liquidus temperature suggest that many so-called ‘equilibrium’ phase relations determined from experiments of a few hours' duration could be in serious error if the ‘equilibration’ involves a nucleation process.

It is demonstrated that, over a range of cooling rates, the temperature at which plagioclase begins to crystallize on cooling varies markedly and the temperature and times required for both possible and certain nucleation of plagioclase are calculated for a range of constant cooling rates. The range of cooling rates over which the nucleation temperature of plagioclase varies is likely to occur in nature only in certain lava flows and small minor intrusions. In such cases this could lead to changes in the order in which the minerals appear on cooling and other petrologically significant effects.
Magnesian siderite in carbonate concretions from argillaceous sediments in the Westphalian of Yorkshire
Authors: Pearson M. J.
Published: December 2006

Lattice parameters have been determined for two coexisting siderite phases in concretions of Westphalian age. Chemical evidence indicates that, for one concretion at least, the phase of smaller cell dimensions is a magnesian siderite with around 25 mole % MgCO3. Both abundances and compositions of the two phases vary between concretions whilst a single phase only is present in disseminated siderite. It is thought unlikely that the two phases represent an equilibrium assemblage and a mechanism is suggested by which magnesian siderite could have formed later.
Structure-function analysis reveals discrete β3 integrin inside-out and outside-in signaling pathways in platelets
Authors: Zou Zhiying , Chen Hong , Schmaier Alec A. , Hynes Richard O. , Kahn Mark L.
Published: December 2006

A unique aspect of integrin receptor function is the transmission of bidirectional signals. In platelets αIIbβ3 integrins require “inside-out” signals to bind fibrinogen and form thrombi. Following ligand binding, αIIbβ3 integrins generate “outside-in” signals that contribute to thrombus stability. Because integrin cytoplasmic tails are short and lack enzymatic activity, bidirectional signals are believed to be mediated by interactions with intracellular proteins, but the molecular basis for integrin signal transduction remains poorly understood. In the present study we have used retroviral vectors to express αIIbβ3 integrins with mutant β3 tails in mouse platelets and test mechanisms of bidirectional signaling. Using this approach we identify mutations (eg, β3Y747A) that confer loss of signaling in both directions and others (eg, β3T762A) that confer a selective loss of outside-in signals. These results reveal the presence of discrete bidirectional signaling pathways controlled by integrin β subunits in platelets and describe a high-throughput means of further investigating these pathways in vivo.
Model-driven user interfaces for bioinformatics data resources: regenerating the wheel as an alternative to reinventing it
Authors: Garwood Kevin , Garwood Christopher , Hedeler Cornelia , Griffiths Tony , Swainston Neil , Oliver Stephen G , Paton Norman W
Published: December 2006

Background

The proliferation of data repositories in bioinformatics has resulted in the development of numerous interfaces that allow scientists to browse, search and analyse the data that they contain. Interfaces typically support repository access by means of web pages, but other means are also used, such as desktop applications and command line tools. Interfaces often duplicate functionality amongst each other, and this implies that associated development activities are repeated in different laboratories. Interfaces developed by public laboratories are often created with limited developer resources. In such environments, reducing the time spent on creating user interfaces allows for a better deployment of resources for specialised tasks, such as data integration or analysis. Laboratories maintaining data resources are challenged to reconcile requirements for software that is reliable, functional and flexible with limitations on software development resources.

Results

This paper proposes a model-driven approach for the partial generation of user interfaces for searching and browsing bioinformatics data repositories. Inspired by the Model Driven Architecture (MDA) of the Object Management Group (OMG), we have developed a system that generates interfaces designed for use with bioinformatics resources. This approach helps laboratory domain experts decrease the amount of time they have to spend dealing with the repetitive aspects of user interface development. As a result, the amount of time they can spend on gathering requirements and helping develop specialised features increases. The resulting system is known as Pierre, and has been validated through its application to use cases in the life sciences, including the PEDRoDB proteomics database and the e-Fungi data warehouse.

Conclusion

MDAs focus on generating software from models that describe aspects of service capabilities, and can be applied to support rapid development of repository interfaces in bioinformatics. The Pierre MDA is capable of supporting common database access requirements with a variety of auto-generated interfaces and across a variety of repositories. With Pierre, four kinds of interfaces are generated: web, stand-alone application, text-menu, and command line. The kinds of repositories with which Pierre interfaces have been used are relational, XML and object databases.
Microdialysis shows metabolic effects in skin during fluid resuscitation in burn-injured patients
Authors: Samuelsson Anders , Steinvall Ingrid , Sjöberg Folke
Published: December 2006

Introduction

Established fluid treatment formulas for burn injuries have been challenged as studies have shown the presence of tissue hypoxia during standard resuscitation. Such findings suggest monitoring at the tissue level. This study was performed in patients with major burn injuries to evaluate the microdialysis technique for the continuous assessment of skin metabolic changes during fluid resuscitation and up to four days postburn.

Methods

We conducted an experimental study in patients with a burn injury, as represented by percentage of total body surface area burned (TBSA), of more than 25% in a university eight-bed burns intensive care unit serving about 3.5 million inhabitants. Six patients with a median TBSA percentage of 59% (range 33.5% to 90%) and nine healthy controls were examined by intracutaneous MD, in which recordings of glucose, pyruvate, lactate, glycerol, and urea were performed.

Results

Blood glucose concentration peaked on day two at 9.8 mmol/l (6.8 to 14.0) (median and range) and gradually declined on days three and four, whereas skin glucose in MD continued to increase throughout the study period with maximum values on day four, 8.7 mmol/l (4.9 to 11.0). Controls had significantly lower skin glucose values compared with burn patients, 3.1 mmol/l (1.5 to 4.6) (p < 0.001). Lactate from burn patients was significantly higher than controls in both injured and uninjured skin (MD), 4.6 mmol/l (1.3 to 8.9) and 3.8 mmol/l (1.6 to 7.5), respectively (p < 0.01). The skin lactate/pyruvate ratio (MD) was significantly increased in burn patients on all days (p < 0.001). Skin glycerol (MD) was significantly increased at days three and four in burn patients compared with controls (p < 0.01).

Conclusion

Despite a strategy that fulfilled conventional goals for resuscitation, there were increased lactate/pyruvate ratios, indicative of local acidosis. A corresponding finding was not recorded systemically. We conclude that MD is a promising tool for depicting local metabolic processes that are not fully appreciated when examined systemically. Because the local response in glucose, lactate, and pyruvate metabolism seems to differ from that recorded systemically, this technique may offer a new method of monitoring organs.
Immunosurveillance and Survivin-Specific T-Cell Immunity in Children With High-Risk Neuroblastoma
Authors: Coughlin Christina M. , Fleming Mark D. , Carroll Richard G. , Pawel Bruce R. , Hogarty Michael D. , Shan Xiaochuan , Vance Barbara A. , Cohen Jarish N. , Jairaj Sonya , Lord Elaina M. , Wexler Michael H. , Danet-Desnoyers Gwenn-aël H. , Pinkus Jack L. , Pinkus Geraldine S. , Maris John M. , Grupp Stephan A. , Vonderheide Robert H.
Published: December 2006

Purpose

Tumor immunosurveillance influences oncogenesis and tumor growth, but it remains controversial whether clinical failure of immunosurveillance is a result of lymphocyte dysfunction or tumor escape. In this study, our goal was to characterize the physiology of tumor immunosurveillance in children with high-risk neuroblastoma (HR-NBL).

Patients and Methods

Immunohistopathologic studies were carried out on 26 tumor samples from a cohort of HR-NBL patients diagnosed at Children's Hospital of Philadelphia for the 2-year period from May 2003 to May 2005. Blood from nine HLA-A2+patients in this cohort was analyzed for T cells specific for the antiapoptotic protein survivin.

Results

Survivin protein was expressed by 26 of 26 tumors. In HLA-A2+patients, circulating cytotoxic T lymphocytes (CTLs) specific for survivin were detected by peptide/major histocompatibility complex tetramer analysis in the blood of eight of nine children with HR-NBL at the time of diagnosis. Rather than being selectively rendered anergic in vivo, circulating survivin-specific CTLs were highly functional as shown by cytotoxicity and interferon gamma enzyme-linked immunospot assays in six of nine patients. Survivin-specific CD107a mobilization by T cells was found in five of five patients. By immunohistochemistry, tumor-infiltrating T cells were few or absent in 26 of 26 tumors.

Conclusion

Children with HR-NBL harbor robust cellular immune responses to the universal tumor antigen survivin at the time of diagnosis, but intratumoral T cells are strikingly rare, suggesting a failure of cellular immunosurveillance. Efforts to develop novel therapies that increase T-cell trafficking into tumor nests are warranted.
Requirements for Endothelin type-A receptors and Endothelin-1 signaling in the facial ectoderm for the patterning of skeletogenic neural crest cells in zebrafish
Authors: Nair Sreelaja , Li Wei , Cornell Robert , Schilling Thomas F.
Published: December 2006

Genetic studies in mice and zebrafish have revealed conserved requirements for Endothelin 1 (Edn1) signaling in craniofacial development. Edn1 acts through its cognate type-A receptor (Ednra) to promote ventral skeletal fates and lower-jaw formation. Here, we describe the isolation and characterization of two zebrafish ednra genes - ednra1 and ednra2 -both of which are expressed in skeletal progenitors in the embryonic neural crest. We show that they play partially redundant roles in lower-jaw formation and development of the jaw joint. Knockdown of Ednra1 leads to fusions between upper- and lower-jaw cartilages, whereas the combined loss of Ednra1 and Ednra2 eliminates the lower jaw, similar to edn1-/-mutants. edn1 is expressed in pharyngeal arch ectoderm, mesoderm and endoderm. Tissue-mosaic studies indicate that, among these tissues, a crucial source of Edn1 is the surface ectoderm. This ectoderm also expresses ednrA1 in an edn1-dependent manner, suggesting that edn1 autoregulates its own expression. Collectively, our results indicate that Edn1 from the pharyngeal ectoderm signals through Ednra proteins to direct early dorsoventral patterning of the skeletogenic neural crest.
Lhx1andLhx5maintain the inhibitory-neurotransmitter status of interneurons in the dorsal spinal cord
Authors: Pillai Andrea , Mansouri Ahmed , Behringer Richard , Westphal Heiner , Goulding Martyn
Published: December 2006

Lhx1 and Lhx5 are co-expressed in multiple interneuron cell types in the developing spinal cord. These include early-born dI4 and dI6 inhibitory interneurons, as well as late-born inhibitory dILAneurons (dILA), all of which express the paired-domain transcription factor Pax2. Although it appears that Lhx1 and Lhx5 do not control the initial specification of the neuronal cell types in which they are expressed, we have found a cell-autonomous requirement for either Lhx1 or Lhx5 to maintain the expression of Pax2, Pax5 and Pax8 in dorsal inhibitory neurons at later developmental stages. Lhx1; Lhx5 double-knockout mice exhibit a downregulation of Gad1 and Viaat (Slc32a1) from E13.5 onwards that is closely associated with a decrease in Pax2expression. Pax2 is a key factor for dorsal GABAergic identity, with the expression of Pax5 and Pax8 being differentially dependent on Pax2 in the dorsal horn. In summary, our findings support a model in which the differentiation of GABAergic interneurons in the dorsal cord depends on Pax2, with Lhx1 and Lhx5helping to activate and maintain Pax2 expression in these cells. Lhx1 and Lhx5 therefore function together with Pax2,Pax5 and Pax8 to establish a GABAergic inhibitory-neurotransmitter program in dorsal horn interneurons.
GATA2 functions at multiple steps in hemangioblast development and differentiation
Authors: Lugus Jesse J. , Chung Yun Shin , Mills Jason C. , Kim Shin-Il , Grass Jeffery A. , Kyba Michael , Doherty Jason M. , Bresnick Emery H. , Choi Kyunghee
Published: December 2006

Molecular mechanisms that regulate the generation of hematopoietic and endothelial cells from mesoderm are poorly understood. To define the underlying mechanisms, we compared gene expression profiles between embryonic stem (ES) cell-derived hemangioblasts (Blast-Colony-Forming Cells, BL-CFCs)and their differentiated progeny, Blast cells. Bioinformatic analysis indicated that BL-CFCs resembled other stem cell populations. A role for Gata2, one of the BL-CFC-enriched transcripts, was further characterized by utilizing the in vitro model of ES cell differentiation. Our studies revealed that Gata2 was a direct target of BMP4 and that enforced GATA2 expression upregulated Bmp4, Flk1 and Scl. Conditional GATA2 induction resulted in a temporal-sensitive increase in hemangioblast generation, precocious commitment to erythroid fate, and increased endothelial cell generation. GATA2 additionally conferred a proliferative signal to primitive erythroid progenitors. Collectively, we provide compelling evidence that GATA2 plays specific, contextual roles in the generation of Flk-1+ mesoderm, the Flk-1+Scl+hemangioblast, primitive erythroid and endothelial cells.
Zebrafishatoh1genes: classic proneural activity in the inner ear and regulation by Fgf and Notch
Authors: Millimaki Bonny B. , Sweet Elly M. , Dhason Mary S. , Riley Bruce B.
Published: December 2006

Hair cells of the inner ear develop from an equivalence group marked by expression of the proneural gene Atoh1. In mouse, Atoh1 is necessary for hair cell differentiation, but its role in specifying the equivalence group (proneural function) has been questioned and little is known about its upstream activators. We have addressed these issues in zebrafish. Two zebrafish homologs, atoh1a and atoh1b, are together necessary for hair cell development. These genes crossregulate each other but are differentially required during distinct developmental periods, first in the preotic placode and later in the otic vesicle. Interactions with the Notch pathway confirm that atoh1 genes have early proneural function. Fgf3 and Fgf8 are upstream activators of atoh1 genes during both phases,and foxi1, pax8 and dlx genes regulate atoh1b in the preplacode. A model is presented in which zebrafish atoh1 genes operate in a complex network leading to hair cell development.
Muscle-dependent maturation of tendon cells is induced by post-transcriptional regulation ofstripeA
Authors: Volohonsky Gloria , Edenfeld Gundula , Klämbt Christian , Volk Talila
Published: December 2006

Terminal differentiation of single cells selected from a group of equivalent precursors may be random, or may be regulated by external signals. In the Drosophila embryo, maturation of a single tendon cell from a field of competent precursors is triggered by muscle-dependent signaling. The transcription factor Stripe was reported to induce both the precursor cell phenotype, as well as the terminal differentiation of muscle-bound tendons. The mechanism by which Stripe activates these distinct differentiation programs remained unclear. Here, we demonstrate that each differentiation state is associated with a distinct Stripe isoform and that the Stripe isoforms direct different transcriptional outputs. Importantly, the transition to the mature differentiation state is triggered post-transcriptionally by enhanced production of the stripeA splice variant, which is typical of the tendon mature state. This elevation is mediated by the RNA-binding protein How(S), with levels sensitive to muscle-dependent signals. In how mutant embryos the expression of StripeA is significantly reduced, while overexpression of How(S) enhances StripeA protein as well as mRNA levels in embryos. Analysis of the expression of a stripeAminigene in S-2 cells suggests that this elevation may be due to enhanced splicing of stripeA. Consistently, stripeA mRNA is specifically reduced in embryos mutant for the splicing factor Crn, which physically interacts with How(S). Thus, we demonstrate a mechanism by which tendon cell terminal differentiation is maintained and reinforced by the approaching muscle.
Hox control of morphogen mobility and organ development through regulation of glypican expression
Authors: Crickmore Michael A. , Mann Richard S.
Published: December 2006

Animal bodies are composed of structures that vary in size and shape within and between species. Selector genes generate these differences by altering the expression of effector genes whose identities are largely unknown. Prime candidates for such effector genes are components of morphogen signaling pathways, which control growth and patterning during development. Here we show that in Drosophila the Hox selector gene Ultrabithorax(Ubx) modulates morphogen signaling in the haltere through transcriptional regulation of the glypican dally. Ubx, in combination with the posterior selector gene engrailed (en), represses dally expression in the posterior (P) compartment of the haltere. Compared with the serially homologous wing, where Ubx is not expressed, low levels of posterior dally in the haltere contribute to a reduced P compartment size and an overall smaller appendage size. We also show that one molecular consequence of dally repression in the posterior haltere is to reduce Dpp diffusion into and through the P compartment. Our results suggest that Dpp mobility is biased towards cells with higher levels of Dally and that selector genes modulate organ development by regulating glypican levels.
A uterine decidual cell cytokine ensures pregnancy-dependent adaptations to a physiological stressor
Authors: Alam S. M. Khorshed , Konno Toshihiro , Dai Gouli , Lu Lu , Wang Danhua , Dunmore Judy H. , Godwin Alan R. , Soares Michael J.
Published: December 2006

In the mouse, decidual cells differentiate from uterine stromal cells in response to steroid hormones and signals arising from the embryo. Decidual cells are crucially involved in creating the intrauterine environment conducive to embryonic development. Among their many functions is the production of cytokines related to prolactin (PRL), including decidual prolactin-related protein (DPRP). DPRP is a heparin-binding cytokine, which is abundantly expressed in uterine decidua. In this investigation, we have isolated the mouse Dprp gene, characterized its structure and evaluated its biological role. Dprp-null mice were made by replacing exons 2 to 6 of the Dprp gene with an in-frame enhanced green fluorescent protein (EGFP) gene and a neomycin (neo)resistance cassette. Heterozygous intercross breeding of the mutant mice yielded the expected mendelian ratio. Pregnant heterozygote females expressed EGFP within decidual tissue in locations identical to endogenous DprpmRNA and protein expression. Homozygous Dprp-null mutant male and female mice were viable, exhibited normal postnatal growth rates, were fertile and produced normal litter sizes. A prominent phenotype was observed when pregnant Dprp-null mice were exposed to a physiological stressor. DPRP deficiency interfered with pregnancy-dependent adaptations to hypoxia resulting in pregnancy failure. Termination of pregnancy was associated with aberrations in mesometrial decidual cells, mesometrial vascular integrity, and disruptions in chorioallantoic placenta morphogenesis. The observations suggest that DPRP participates in pregnancy-dependent adaptations to a physiological stressor.
Lmx1bis essential forFgf8andWnt1expression in the isthmic organizer during tectum and cerebellum development in mice
Authors: Guo Chao , Qiu Hai-Yan , Huang Ying , Chen Haixu , Yang Rong-Qiang , Chen Sheng-Di , Johnson Randy L. , Chen Zhou-Feng , Ding Yu-Qiang
Published: December 2006

Secreted factors FGF8 and WNT1 are essential either for the inductive activity of the isthmus organizer or for the regionalization of the midbrain-hindbrain boundary (MHB). However, transcriptional regulation of these secreted factors during development remains to be elucidated. Here we show that the LIM homeobox gene Lmx1b is expressed in the anterior embryo as early as E7.5 and its expression becomes progressively restricted to the isthmus at E9.0. Analysis of gene expression in the MHB of the mutant embryos showed that many genes were lost by E9.5. In the MHB of Lmx1b-/- embryos, the expression of Fgf8, which normally occurs at the 4-somite stage, was completely absent, whereas Wnt1 was downregulated before the 4-somite stage. Moreover,transcription factors En1 and Pax2 were also downregulated prior to the 4-somite stage, whereas Gbx2 downregulation occurred at the 4-somite stage. By contrast, Otx2 and Pax6 expression was not affected in Lmx1b-/- embryos. The requirement of specific Lmx1b expression in the MHB was further confirmed by Wnt1-Cre-mediated region-specific conditional knockout of Lmx1b. As a result of these molecular defects, the development of the tectum and cerebellum was severely impaired in Lmx1b-/-mice. Taken together, our results indicate that Lmx1b plays an essential role in the development of the tectum and cerebellum by regulating expression of Fgf8, Wnt1 and several isthmus-related transcription factors in the MHB, and is a crucial component of a cross-regulatory network required for the induction activity of the isthmic organizer in the MHB.
On the depth and scale of metabolic rate variation: scaling of oxygen consumption rates and enzymatic activity in the Class Cephalopoda(Mollusca)
Authors: Seibel Brad A.
Published: December 2006

Recent ecological theory depends, for predictive power, on the apparent similarity of metabolic rates within broad taxonomic or functional groups of organisms (e.g. invertebrates or ectotherms). Such metabolic commonality is challenged here, as I demonstrate more than 200-fold variation in metabolic rates independent of body mass and temperature in a single class of animals,the Cephalopoda, over seven orders of magnitude size range. I further demonstrate wide variation in the slopes of metabolic scaling curves. The observed variation in metabolism reflects differential selection among species for locomotory capacity rather than mass or temperature constraints. Such selection is highest among epipelagic squids (Lolignidae and Ommastrephidae)that, as adults, have temperature-corrected metabolic rates higher than mammals of similar size.
Analyzing the effect of wind on flight: pitfalls and solutions
Authors: Shamoun-Baranes Judy , van Loon Emiel , Liechti Felix , Bouten Willem
Published: December 2006

How flying organisms alter their air speed in response to wind is important in theories of flight energetics. Numerous studies have investigated the relationship between air and wind as a function of ground speed and air speed. This study shows that this approach can lead to erroneous results, due to spurious correlations. An alternative way to analyze air speed is proposed that overcomes the problems of one-dimensional linear models. The new model is non-linear and has two explanatory variables. Using two synthetic data sets with known properties and a data set with real observations of migratory bird tracks and wind observations, we illustrate the weaknesses of the conventional analysis as well as the strengths of the newly proposed model. This leads to the conclusion that for many studies a reanalysis of the effect of wind on air speed is desirable.
Reversibly labile, sclerotization-induced elastic properties in a keratin analog from marine snails: whelk egg capsule biopolymer (WECB)
Authors: Rapoport H. Scott , Shadwick Robert E.
Published: December 2006

Egg capsules from two caenogastropod whelks, Busycon canaliculatumand Kelletia kelletii, were studied to investigate the genesis of mechanical properties of nascent capsules and to formulate a biomechanical model of this material. Scanning electron microscopy revealed that the capsules possess fibrous hierarchical arrangements at all stages during processing while the mechanical integrity is developing. This suggests that an as yet uncharacterized sclerotization mechanism occurring in the ventral pedal gland primarily binds these fibrous components together. Decomposing the mechanical behavior of WECB through various physical and chemical treatments led us to develop a model for the structure and mechanical properties of this material that supports its designation as a keratin analog. Keratin mechanical models were applied to WECB in its representation as an intermediate state between matrix-free intermediate filament (IF)-type proteins and the more complex composite materials incorporating IFs such as keratin.
Phenotypic flexibility in the basal metabolic rate of laughing doves:responses to short-term thermal acclimation
Authors: McKechnie Andrew E. , Chetty Kinesh , Lovegrove Barry G.
Published: December 2006

Many birds exhibit considerable phenotypic flexibility in maintenance energy requirements, and up- or downregulate basal metabolic rate (BMR) over time scales of days to weeks during thermal acclimation. However, the extent to which individual birds can reverse the direction of BMR adjustments over short time scales remains unknown. In this study, we examined metabolic responses to short-term thermal acclimation in laughing doves Streptopelia senegalensis. In 30 wild-caught doves (mean body mass=92.6 g) divided into three experimental groups of 10 birds each, initial BMR averaged 0.760±0.036 W. Thereafter, each group was acclimated to one of three acclimation air temperatures (Tacc=10, 22 or 35°C) for 21 days, during which time the doves were housed in individual cages. Following the first acclimation period (acclimation I), BMR (W) was significantly lower and was negatively and linearly related to Tacc [BMR=0.714-0.005Tacc]. Acclimation I BMR varied from 0.546±0.039 W in doves acclimated to Tacc=35°C to 0.665±0.058 W at Tacc=10°C. A second acclimation period of a further 21 days (acclimation II) revealed that the direction of BMR adjustments could be reversed within individuals, with acclimation II BMR again negatively and linearly related to Tacc. The slope of the relationship between BMR and Tacc following acclimation II was not significantly different to that following acclimation I. BMR exhibited consistent inter-individual variation, with a low but significant repeatability of 0.113. The within-individual BMR variation of up to 26% that we observed in laughing doves reveals that BMR is a highly flexible trait in this species, and reiterates the need to take phenotypic plasticity into account in comparative analyses of avian energetic parameters.
Chemicalversusmechanical bioerosion of coral reefs by boring sponges - lessons fromPione cf. vastifica
Authors: Zundelevich A. , Lazar B. , Ilan M.
Published: December 2006

Bioerosion by boring sponges is an important mechanism shaping the structure of coral reefs all around the world. To determine the excavation rate by boring sponges, we developed a system in which chemical and mechanical boring rates [calcium carbonate (CaCO3) dissolution and chip production, respectively] were measured simultaneously in experimental tanks containing reefal rock inhabited by a boring sponge. Pione cf. vastifica (Hancock 1849) was chosen as a model species to study the erosion rate of boring sponges. It is an abundant species in the coral reefs of the Nature Reserve Reef, Elat, Gulf of Aqaba, northern Red Sea, reaching maximum abundance at 25-30 m. The rate of chemical bioerosion was determined from the increase in tank-seawater alkalinity over time, and the mechanical bioerosion rate was estimated from the total amount of CaCO3 chips produced over the same time interval. The measured bioerosion rate of P. cf. vastifica was 2.3 g m-2 sponge day-1, showing seasonal but not diurnal variations, suggesting that the zooxanthellae harboring the sponge have no effect on its boring rate. The experiments indicated clearly that per each mass of chips that P. cf. vastificaproduces during its boring activity, it dissolves three masses of reef CaCO3 framework. Assuming that some additional boring sponges can use a similar strategy of bioerosion, these findings suggest that chips, the most obvious erosion products of boring sponges, represent only a small fraction of boring sponge bioerosion capacity.
Feeding, fins and braking maneuvers: locomotion during prey capture in centrarchid fishes
Authors: Higham Timothy E.
Published: December 2006

Locomotion is an integral aspect of the prey capture strategy of almost every predatory animal. For fishes that employ suction to draw prey into their mouths, locomotor movements are vital for the correct positioning of the mouth relative to the prey item. Despite this, little is known regarding the relationships between locomotor movements and prey capture. To gain insights into how fishes move during prey capture and the mechanisms underlying deceleration during prey capture, I measured the fin and body movements of largemouth bass, Micropterus salmoides, and bluegill sunfish, Lepomis macrochirus. Using a high-speed video camera (500 frames s-1), I captured locomotor and feeding movements in lateral and ventral (via a mirror) view. Largemouth bass swam considerably faster than bluegill during the approach to the prey item, and both species decelerated substantially following prey capture. The mean magnitude of deceleration was significantly higher in largemouth bass (-1089 cm s-2) than bluegill (-235 cm s-2), and the timing of maximum deceleration was much later for largemouth bass (30.3 ms after maximum gape) than bluegill (6.7 ms after maximum gape). Both species employed their pectoral, anal and caudal fins in order to decelerate during prey capture. However, largemouth bass protracted their pectoral fins more and faster,likely contributing to the greater magnitude of deceleration in the species. The primary mechanism for increased deceleration was an increase in approach speed. The drag forces experienced by the fins and body are proportional to the velocity of the flow squared. Thus, the braking forces exerted by fins,without any change in kinematics, will increase exponentially with small increases in swimming speed, perhaps allowing these fishes to achieve higher braking forces at higher swimming speeds without altering body or fin kinematics. This result can likely be extended to other maneuvers such as turning.
Preparation of Ag Core–Cu Shell Nanoparticles by Microwave-assisted Alcohol Reduction Process
Authors: Nakamura Takashi , Tsukahara Yasunori , Yamauchi Tomohisa , Sakata Takao , Mori Hirotaro , Wada Yuji
Published: December 2006

We have succeeded in rapidly preparing Ag core–Cu shell nanoparticles (denoted as Cu/Ag nanoparticles) having 10–40 nm in size by a microwave (MW)-assisted alcohol reduction process. The core–shell nanoparticles were prepared by step-by-step successive reduction of a silver precursor and then of a copper precursor added after the formation of silver nanoparticles in 1-heptanol.
Photoluminescence Property of Titanate Layered Oxide Intercalated with Tb3+ Ions by Electrostatic Self-assembly Deposition Method
Authors: Ida Shintaro , Ogata Chikako , Inoue Taishi , Izawa Kazuyoshi , Unal Ugur , Altuntasoglu Ozge , Matsumoto Yasumichi
Published: December 2006

Titanate layered oxide intercalated with Tb3+ ions was prepared by electrostatic self-assembly deposition method using the exfoliated H2Ti4O9 (Ti4O9 nanosheet). The naked Tb3+ green emission through energy transfer from Ti4O9 nanosheet was observed. The efficiency of the energy transfer decreased with decrease in the layer distance.
Adolf Harnacks Vorlesung über ‚Encyklopädie der Theologie‘ (1884)
Authors: Steck Friedemann
Published: December 2006

In the course of his active teaching career of over fifty years, Adolf von Harnack only once lectured on the „Encyclopaedia of Theology“. This occured in the summer of 1884 when he was a young university professor in Gießen, lecturing twice a week from 9 to 10 in the morning. The handwritten script of the dictation booklet (36 pp.) has so far gone unnoticed in the literature. It is documented here for the first time and in a full reproduction. These lecture notes present a condensed, overall impression of Harnack's concept of theology, probably unlike any other his texts. Of particular interest is the detailed outline of a concept of religion that Harnack developed through an intense examination of drafts on this topic by Friedrich Schleiermacher and Albrecht Ritschl as well as Ritschl's prominent students, Julius Kaftan and Wilhelm Herrmann. Within the history of Harnack's opus, the lecture for the Encyclopaedia was done in close working relationship with the great literary project of the Lehrbuch der Dogmengeschichte (1885–89).
Theologiestudium in Tübingen vor 100 Jahren – im Spiegel der Briefe des Studienanfängers Paul Althaus an seine Eltern
Authors: Jasper Gotthard
Published: December 2006

In view of the subsequent career of the leading Lutheran theologian Paul Althaus (1888–1966), the student letters reproduced here obtain considerable biographical weight: 1913 doctorate in Göttingen, 1914 habilitated and a privatdozent, during the war an volunteer orderly, then a hospital and provincial pastor in Lodz, 1919–1924 Professor in Rostock, 1924–1966 Professor of systematic theology and New Testament exegesis in Erlangen. Althaus' letters shed light on the family and confessional traditions in which he originated, just as they do on his connections with a fervent church as well as a national and patriotic life. In addition, they illustrate the outstanding powers of observation and formulation as well as the intelligence and wide interests of the young student, all qualities of importance for his later career. In addition, the student letters of the 18–19 year old Paul Althaus describe the conditions of studying in Tübingen a hundred years ago. The professors then instructing there, among them, especially Adolf Schlatter, are also vividly described in their various roles, just as the letters richly narrate aspects of the general conduct of studies, life in fraternities – Althaus was active in the Nicaren, a non-duelling Christian association – as well as the many student rambles through the woods.
Anwendung dynamischer Kräfte in der Werkstoffprüfung (Application of Dynamic Forces in Materials Testing)
Authors: Herrmann Konrad , Patkovszky Imre , Behrens Bernd-Arno , Kammler Matthias
Published: December 2006

Zur Charakterisierung von Werkstoffeigenschaften unter dynamischer Beanspruchung werden in der Werkstoffprüfung verschiedene dynamische Prüfverfahren angewendet. Darüber hinaus werden dynamische Prüfverfahren auch zunehmend anstelle statischer Prüfverfahren eingesetzt. Dieser Beitrag stellt als typische Anwendungsbeispiele für dynamische Kräfte in der Werkstoffprüfung die dynamische Härtemessung und die dynamische Schleifscheibenprüfung vor.
Experimentelle und theoretische Untersuchungen zum Resonanzverhalten piezoelektrischer Kraftaufnehmer (Experimental and Theoretical Investigations of the Resonant Behaviour of Piezoelectric Force Transducers)
Authors: Kobusch Michael , Mack Oliver , Bruns Thomas
Published: December 2006

Der vorliegende Beitrag behandelt aktuelle Untersuchungen zum Resonanzverhalten piezoelektrischer Kraftaufnehmer. Neben exemplarischen Messungen der Resonanzfrequenz werden verschiedene analytische Ansätze zur Modellierung des dynamischen Verhaltens vorgestellt und diskutiert.
Dynamische Eigenschaften von Kraftaufnehmern bei Aufpralltests (Dynamic Properties of Force Sensors at Impact Tests)
Authors: Evers Wolfgang , Schading Georg
Published: December 2006

Zur Messung hochdynamischer Kraftsignale oder Stoßvorgänge werden piezoelektrische Kraftaufnehmer eingesetzt, wie z.B. bei instrumentierten Crash-Barrieren für Aufpralltests von Fahrzeugen oder bei Kraftmessplatten in Falltürmen zur Untersuchung von energie-absorbierenden Stoßfängern. Piezoelektrische Kraftaufnehmer zeichnen sich durch eine sehr hohe Empfindlichkeit und Eigenfrequenz des sensitiven Messelementes aus, wodurch diese zur Messung von dynamischen und stoßartigen Kräften prädestiniert sind. Neben den statischen Kenngrößen sind die dynamischen Übertragungseigenschaften des Messelementes wichtig, weil diese den zulässigen Einsatzbereich für die jeweiligen Messaufgaben bestimmen. Die wichtigsten Kenngrößen sind das frequenzabhängige Übertragungsverhalten, die Eigen- und Resonanzfrequenzen sowie die Dämpfungseigenschaften und die Ansprechgeschwindigkeit.
Dynamische Drehmomentmessung. Drehmomentaufnehmer in Leistungsprüfständen (Dynamic Torque Measurement. Torque Transducers in Power Test Stands)
Authors: Andrae Jürgen , Wegener Georg
Published: December 2006

In diesem Beitrag soll näher darauf eingegangen werden, wie dynamische Drehmomente in Leistungsprüfständen entstehen und welche Auswirkungen sie auf den Drehmomentaufnehmer und auf das Messsignal haben.

Als dynamische Drehmomentquellen fungieren Verbrennungsmotoren sowie elektrische Antriebe, aber auch parasitäre Einflüsse können dynamische Drehmomentanteile erzeugen. Aufgrund des mechanischen Übertragungsverhaltens des Wellenstrangs, in den der Drehmomentaufnehmer integriert ist, können die erzeugten dynamischen Belastungen als Anregung für Torsions-, Axial- und Biegeschwingungen fungieren. Die Kenntnis oder Abschätzung dieser Belastungen sind für die Auswahl eines geeigneten Drehmomentaufnehmers entscheidend.
Identification of a novel melanocortin 2 receptor splice variant in murine adipocytes: implications for post-transcriptional control of expression during adipogenesis
Authors: Noon Luke A , Bakmanidis Artem , Clark Adrian J L , O’Shaughnessy Peter J , King Peter J
Published: December 2006

The ACTH receptor melanocortin 2 receptor (MC2-R) is a G-protein-coupled receptor principally expressed in the adrenal cortex and the adipocyte, where it stimulates steroidogenesis and lipolysis respectively. The coding region of the murine gene is encoded by a single exon, although three upstream non-coding exons have been documented, one of which is incorporated by alternative splicing in adrenal cells. We have detected a novel transcript in adipocytes, which includes a previously unidentified 86 bp exon upstream of the coding region. This transcript appears with slower kinetics during a time course of differentiation of 3T3-L1 cells and is much more highly expressed in these cells and murine adipose tissues than in the Y1 murine adrenocortical cell line, also it is undetectable in murine foetal testes. Inclusion of this exon extends the 5′ UTR to 468 bp and introduces three upstream open reading frames. These are typical features of mRNAs under translational control and imply that the MC2-R gene is regulated both transcriptionally and post-transcriptionally during adipogenesis.
Growth factor-dependent regulation of survivin by c-myc in human breast cancer
Authors: Cosgrave Niamh , Hill Arnold D K , Young Leonie S
Published: December 2006

Survivin has emerged as a unique regulator of cell death through its response to growth factors, such as basic fibroblast growth factor (bFGF), which we have previously shown to be mitogen-activated protein kinase (MAPK) dependent. The transcriptional complex myc/max is an oncogene that lies downstream of the MAPK pathway, suggesting a possible role in survivin’s regulation. In this study, we investigated the ability of bFGF to induce signalling of the MAPK effector transcription factor c-myc in human breast cancer. Treatment of SK-BR-3 breast cancer cell line with growth factor induced survivin expression and recruitment of c-myc to its response element in the promoter region of the target gene survivin as demonstrated by electromobility shift analysis and chromatin immunoprecipitation assays. The promoter region of survivin was assessed using bioinformatic techniques and DNA footprinting. Overexpression of c-myc increased survivin protein expression. This effect was eliminated when siRNA against c-myc was transfected into the cells. c-Myc drove transcriptional activity of survivin when transfected into SK-BR-3 cells with a luciferase reporter vector harbouring the c-myc response element specific for survivin. Using confocal fluorescent microscopy, myc was located to the nucleus of breast tumour epithelial cells and was found to be significantly associated with survivin (P < 0.0001). These data provide evidence that growth factors can signal through the transcription factor c-myc in human breast cancer. They also indicate a role for c-myc in the transcriptional regulation of survivin in breast cancer.
Corticotropin-releasing hormone inhibits progesterone production in cultured human placental trophoblasts
Authors: Yang Ruifang , You Xingji , Tang Xiaolu , Gao Lu , Ni Xin
Published: December 2006

Placental-derived corticotropin-releasing hormone (CRH) seems to play a major role in the mechanisms controlling human pregnancy and parturition. It has been suggested that CRH directly modulates the endocrine function of placental trophoblasts, including the production of estrogen, ACTH, and prostaglandin. In this study, we sought to investigate the effect of CRH, locally produced by placenta, on progesterone production. Percoll-purified placental trophoblasts were obtained from uncomplicated term pregnancies and cultured for 72 h. Progesterone concentration in culture media was measured by RIA. The mRNA transcripts encoding CYP11A1 and HSD3B1, the enzymes for progesterone synthesis, were determined by quantitative real-time reverse transcription (RT)-PCR. Results showed that CRH (10−8–10−6 mol/l) caused a significant decrease in progesterone levels in a dose-dependent manner. The CRH antagonist, α-helical CRH 9-41, at 10−7–10−5 mol/l stimulated progesterone secretion. Consistent with this thesis, CRH decreased, whereas α-helical CRH increased, the mRNA levels of CYP11A1 and HSD3B1. Since CRH has been shown to activate the phospholipase C–protein kinase C (PKC) signal pathway in placenta, we examined whether the effect of CRH on progesterone synthesis was dependent on PKC signal pathway. Treatment of cells with PKC inhibitor, Gö6976, resulted in a significant increase in progesterone production, and exogenous CRH restored progesterone production. In conclusion, placental CRH exhibits a tonic inhibitory effect on progesterone production in a PKC-dependent fashion.