bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Methods for Realizing Nonstationary Poisson Processes with Piecewise-Constant Instantaneous-Rate Functions
Authors: Harrod Steven , Kelton W. David
Published: June 2006

Nonstationary Poisson processes are appropriate in many applications, including disease studies, transportation, finance, and social policy. The authors review the risks of ignoring nonstationarity in Poisson processes and demonstrate three algorithms for generation of Poisson processes with piecewise-constant instantaneous rate functions, a capability that has been implemented in commercial simulation software. They test these algorithms in C programs and make comparisons of accuracy, speed, and variability across disparate rate functions and microprocessor architectures. Choice of optimal algorithm could not be predicted without knowledge of microprocessor architecture.
‘Impossible is a fact’: Greek nationalism and international recognition in Euro 2004
Authors: Tzanelli Rodanthi
Published: June 2006

This article explores the ways in which the ‘nation’ is discussed in the press. Theoretically, it argues that the national ‘self’ emerges through dialogue with ‘others’. Reconsidering Anderson's argument, it suggests that national identity is often the product of international recognition that enables the national community to ‘imagine’ itself. Contextually, it looks at Greek newspaper commentary following the victory of the Greek football team in the Euro 2004 tournament. The Greek national ‘self’ emerged in such commentary in many ways: first, through the uses of its Christian and Hellenic heritage that European nations admire; second, through the projection of the ‘Greek nation’ outwards, as a diasporic community; and, third, through the construction of (racist) stereotyping of ‘Greek football enemies’ and ‘friends’. The article concludes by examining the role of international praise or criticism in the promotion of a Greek political agenda abroad.
Low-melting Phthalonitrile Oligomers: Preparation, Polymerization and Polymer Properties
Authors: Dominguez Dawn D. , Keller Teddy M.
Published: June 2006

A series of low-melting phthalonitrile oligomers were prepared in which variable-length multiple aromatic ether linkages interconnect the terminal phthalonitrile units. These materials were designed to address the need for a processable resin system with good high-temperature properties. The melt-processable oligomers are obtained using a modified-Ullman ether reaction between a bisphenol and a dihalobenzene to form a hydroxyl-terminated oligomeric intermediate that is endcapped by reaction with 4-nitrophthalonitrile. Viscosity measurements show that the phthalonitrile oligomers are polymerized at a moderate temperature (200°C) using the typical aromatic diamine curing additives, bis[4-(4-aminophenoxy)phenyl]sulfone and 1,3-bis(3-aminophenoxy)benzene. The oligomeric phthalonitrile/diamine mixtures exhibit a low complex melt viscosity (0.01-0.1 Pa s) at 200°C. Differential scanning calorimetric analysis is used to follow the polymerization as the oligomeric phthalonitrile/diamine mixtures are heated to elevated temperatures. Thermal and dynamic mechanical properties of thermally-cured oligomeric phthalonitrile polymers are systematically evaluated and compared with those of two other high temperature thermosetting phthalonitrile polymers, 4,4~-bis(3,4-dicyanophenoxy)biphenyl and 1,3- bis(3,4-dicyanophenoxy)benzene. After thermal treatment at 425°C for 8 h, the oligomeric phthalonitrile polymers exhibit char yields of 70% when heated to 1000°C in flowing nitrogen and decomposition temperatures in excess of 500°C when heated in either flowing nitrogen or air. Rheometric measurements indicate that the fully cured oligomeric phthalonitrile polymers do not soften or exhibit a glass transition temperature upon heating to 450°C. Overall, studies on the phthalonitrile oligomers and the corresponding polymers reveal an attractive combination of processability, thermal and thermo-oxidative stability and good dynamic mechanical properties for these materials
Electrochemical Synthesis of some Polyazomethines by Organometallic Reductive Catalysis
Authors: Conduruta Daniel , Cianga Ican , Airinei Anton , Grigoras Mircea , Ivanoiu Maria
Published: June 2006

Three monomers with preformed Schiff base structures and ~nal bromine atoms were synthesized: N, N°-bis(4-bromophenyl)-terephthaldiimine (I), N, N°-bis(4-bromobenzylidene)-benzene-1,4-dia-mine (II) and N-(4-bromobenzylidene)-4°-bromoaniline (III). All these compounds were used to prepare polyazomethines by dehalogenative coupling reactions via organometallic reductive catalysis (Ni0.bipy). The monomers and corresponding polymers were characterized by spectral methods (FT-IR, 1HNMR, UV-Vis) as well as by thermal analysis
Nylon 6/SiO2Nanocomposites Synthesized by in situAnionic Polymerization
Authors: Rusu Gheorghe , Rusu Elena
Published: June 2006

In situ anionic polymerization of °-caprolactam in the presence of SiO2 and silanated SiO2nanoparticles was promoted as a route for the synthesis of two series of nylon 6/SiO2 nanocomposites. The process was performed at 160°C well below the melting temperature of the nylon 6 ( Tm ~ 225°C) and initiated/activated with sodium dicaprolactamato-bis(2-methoxyethoxo)aluminate/ N, N′[methylene-di(4,4′phenylene)bis-carbamoyl]bis- δ-caprolactam system. The nanocomposites obtained exhibit higher onset decomposition temperatures than neat nylon 6 and a tendency of reduction of the polymer yields, degree of polymerization, water absorption and melting temperatures with silica content increasing. The crystallization temperature, Tc of the nanocomposites reaches a maximum value at 2.0 wt.% of the nanoparticles. The mechanical tests of nanocomposites revealed an increase in flexural modulus as a function of filler percentage and a decrease in notched impact strength by addition of the modified silica (over 4.0 wt.%) and unmodified silica. Furthermore, the flexural strength diminishes both the treated and untreated filler content is increased for concentration of ~ 4.0 wt.%
A Novel Calculus? Institutional Change, Globalization and Industrial Conflict in Europe
Authors: Scheuer Steen
Published: June 2006

Collective industrial conflict in Europe has declined dramatically since the 1970s. This decline is the result of significant changes in institutional factors, influencing the calculations of employees and their organizations when considering strike action. Declining union density and changes in market protection seem major influences, while institutional and legal changes are important explanations of persistent major inter-country variance. This indicates a novel industrial conflict calculus for employees, which entails a more restricted use, but not the withering away of the strike.
A Decade after Cairo
Authors: Nair Sumati , Sexton Sarah , Kirbat Preeti
Published: June 2006

The Programme of Action issued by the 1994 UN International Conference on Population and Development was the first and most wide-ranging international policy document to promote the concepts of reproductive rights and reproductive health. Its major recommendation was that population programmes should provide comprehensive reproductive health services integrated and coordinated with each other and with other health services. It put women at its centre and expressly rejected the use of incentives and targets in family planning services. But the Programme of Action is still far from being implemented because health services are declining or have collapsed; the underlying conditions determining women's health and their control over childbearing are deteriorating; fundamentalisms opposing women's rights are on the rise; and neo-Malthusian thinking is as ingrained as ever in development institutions, donor agencies and government departments. These negative forces on women's health can be attributed to the implementation of neo-liberal economic and health policies over the past two decades. The Programme of Action, together with the accompanying political organising by international women's organisations and population groups, did not challenge neo-liberalism sufficiently, but endorsed it in several respects. It thereby undermined its ground-breaking principles and goals of reproductive health.
A Decade after Cairo in Latin America
Authors: Rosenberg Martha
Published: June 2006

To understand what has happened to women's health in Latin America over a decade or more since the Cairo conference, one has to analyse how Latin America has been affected by ‘globalisation’. Exploitation has been globalised with the transnational circulation of profits, and capital can now grow at the expense of the resources and labour of any country in the world. Areas of social life that had hitherto not been ruled by the logic of profit were now commercialised. In Latin America, unemployment increased, average salaries decreased, and the precariousness of working conditions grew dramatically. Services that had been accessible to most people were privatised, thereby increasing inequality between poorer people and the rest of society; thus, in turn, has increased the pressure on households that are mainly run by women—in Argentina, these form nearly one-third of the households. Using examples from Argentina, this article describes how the economic changes brought about by the processes of globalisation have had an impact on the lives of women in Latin America. These are, in turn, seen in relation to the Cairo commitments. It also traces the reactions of feminist and women's movements to the challenges posed by these changes.
The Advantages of Evolving Perceptual Cues
Authors: Macinnes Ian , Di Paolo Ezequiel
Published: June 2006

This paper introduces the evolvable functional circle hypothesis. This hypothesis states that if it is assumed that von Uexküll’s concept of functional circles exists in robots and that the models used in evolutionary robotics are altered accordingly, then practitioners of evolutionary robotics will benefit in two ways. The first way is that by promoting the evolution of functional circles rather than sensorimotor loops, it allows evolved robots to select their own stimuli and therefore find their own meaning from environmental information. The second way is that it makes it easier for evolved robots to derive multiple meanings from the signal produced by a sensor. The paper goes on to demonstrate a method to alter our models in evolutionary robotics to promote the evolution of functional circles
Principles of Minimal Cognition: Casting Cognition as Sensorimotor Coordination
Authors: van Duijn Marc , Keijzer Fred , Franken Daan
Published: June 2006

Within the cognitive sciences, cognition tends to be interpreted from an anthropocentric perspective, involving a stringent set of human capabilities. Instead, we suggest that cognition is better explicated as a much more general biological phenomenon, allowing the lower bound of cognition to extend much further down the phylogenetic scale. We argue that elementary forms of cognition can already be witnessed in prokaryotes possessing a functional sensorimotor analogue of the nervous system. Building on a case-study of the Escherichia coli bacterium and its sensorimotor system, the TCST-system, we home in on the characteristics of minimal cognition, and distinguish it from more basic forms of ontogenetic adaptation. In our view, minimal cognition requires an embodiment consisting of a sensorimotor coupling mechanism that subsumes an autopoietic organization; this forms the basis of the growing consensus that the core of cognition revolves around sensorimotor coupling. We discuss the relevance of our interpretation of minimal cognition for the study of cognition in general
Globalization, Organization and the Ethics of Liberation
Authors: Dussel Enrique , Ibarra-Colado Eduardo
Published: June 2006

The paper discusses three related issues that have a growing importance in the light of current developments in the contemporary debates around modernity and its future. These are globalization, organization and the ethics of liberation. The first section recognizes the specific meaning of globalization when it is confronted with the prevailing Eurocentrism. The result should be a critical posture that understands the world as a system that goes far beyond Europe. The second section discusses the nature of the problems of organization related to globalization. The organization of human activities related to production and commerce required a permanent process of ‘simplification’. This was achieved by means of the ‘rationalization’ of the world of life in all its economic, political, cultural and religious subsystems. One of its undeniable consequences has been the production of victims and exclusion, proving the asymmetrical organization of ‘modern’ life. The final section, centred in the ethics of liberation, will allow us to clarify the elements and determinants for the transformation of this modern condition to guarantee the production, reproduction and development of life. A new type of theoretical possibility emerges to think of the world as a trans-modern organization of life characterized by its plurality, diversity and reasonability.
International collaborations in nursing research
Authors: Chiang-Hanisko Lenny , Ross Ratchneewan , Ludwick Ruth , Martsolf Donna
Published: June 2006

The purpose of this paper is to present a framework for dialogue for university-based nursing programmes that are planning and developing international research programmes. Future trends will continue to drive the need for international research due to the globalisation of healthcare issues. Nursing, as one of the main providers of healthcare services, can play a larger role in improving healthcare globally, by leading the way in international collaborative research. A definition of international nursing research is offered, as well as a framework consisting of three broad issues for discussing international work. The three foci of the framework are (a) international nursing research priorities, (b) rewards of international nursing collaborations and (c) challenges of these collaborations. Examples of international collaborative nursing research experiences with nurses in Haiti, Taiwan, Thailand and the United Kingdom are examined, along with lessons learned
Targeted disruption of cubilin reveals essential developmental roles in the structure and function of endoderm and in somite formation
Authors: Smith Brian T , Mussell Jason C , Fleming Paul A , Barth Jeremy L , Spyropoulos Demetri D , Cooley Marion A , Drake Christopher J , Argraves W Scott
Published: June 2006

Background

Cubilin is a peripheral membrane protein that interacts with the integral membrane proteins megalin and amnionless to mediate ligand endocytosis by absorptive epithelia such as the extraembryonic visceral endoderm (VE).

Results

Here we report the effects of the genetic deletion of cubilin on mouse embryonic development. Cubilin gene deletion is homozygous embryonic lethal with death occurring between 7.5–13.5 days post coitum (dpc). Cubilin-deficient embryos display developmental retardation and do not advance morphologically beyond the gross appearance of wild-type 8–8.5 dpc embryos. While mesodermal structures such as the allantois and the heart are formed in cubilin mutants, other mesoderm-derived tissues are anomalous or absent. Yolk sac blood islands are formed in cubilin mutants but are unusually large, and the yolk sac blood vessels fail to undergo remodeling. Furthermore, somite formation does not occur in cubilin mutants. Morphological abnormalities of endoderm occur in cubilin mutants and include a stratified epithelium in place of the normally simple columnar VE epithelium and a stratified cuboidal epithelium in place of the normally simple squamous epithelium of the definitive endoderm. Cubilin-deficient VE is also functionally defective, unable to mediate uptake of maternally derived high-density lipoprotein (HDL).

Conclusion

In summary, cubilin is required for embryonic development and is essential for the formation of somites, definitive endoderm and VE and for the absorptive function of VE including the process of maternal-embryo transport of HDL.
The CAP cancer protocols – a case study of caCORE based data standards implementation to integrate with the Cancer Biomedical Informatics Grid
Authors: Tobias Jonathan , Chilukuri Ram , Komatsoulis George A , Mohanty Sambit , Sioutos Nicholas , Warzel Denise B , Wright Lawrence W , Crowley Rebecca S
Published: June 2006

Background

The Cancer Biomedical Informatics Grid (caBIG™) is a network of individuals and institutions, creating a world wide web of cancer research. An important aspect of this informatics effort is the development of consistent practices for data standards development, using a multi-tier approach that facilitates semantic interoperability of systems. The semantic tiers include (1) information models, (2) common data elements, and (3) controlled terminologies and ontologies. The College of American Pathologists (CAP) cancer protocols and checklists are an important reporting standard in pathology, for which no complete electronic data standard is currently available.

Methods

In this manuscript, we provide a case study of Cancer Common Ontologic Representation Environment (caCORE) data standard implementation of the CAP cancer protocols and checklists model – an existing and complex paper based standard. We illustrate the basic principles, goals and methodology for developing caBIG™ models.

Results

Using this example, we describe the process required to develop the model, the technologies and data standards on which the process and models are based, and the results of the modeling effort. We address difficulties we encountered and modifications to caCORE that will address these problems. In addition, we describe four ongoing development projects that will use the emerging CAP data standards to achieve integration of tissue banking and laboratory information systems.

Conclusion

The CAP cancer checklists can be used as the basis for an electronic data standard in pathology using the caBIG™ semantic modeling methodology.
Follicle-stimulating hormone (FSH) activates extracellular signal-regulated kinase phosphorylation independently of beta-arrestin- and dynamin-mediated FSH receptor internalization
Authors: Piketty Vincent , Kara Elodie , Guillou Florian , Reiter Eric , Crepieux Pascale
Published: June 2006

Background

The follicle-stimulating hormone receptor (FSH-R) is a seven transmembrane spanning receptor (7TMR) which plays a crucial role in male and female reproduction. Upon FSH stimulation, the FSH-R activates the extracellular signal-regulated kinases (ERK). However, the mechanisms whereby the agonist-stimulated FSH-R activates ERK are poorly understood. In order to activate ERK, some 7 TMRs require beta-arrestin-and dynamin-dependent internalization to occur, whereas some others do not. In the present study, we examined the ability of the FSH-activated FSH-R to induce ERK phosphorylation, in conditions where its beta-arrestin- and dynamin-mediated internalization was impaired.

Methods

Human embryonic kidney (HEK) 293 cells were transiently transfected with the rat FSH-R. Internalization of the FSH-R was manipulated by co-expression of either a beta-arrestin (319–418) dominant negative peptide, either an inactive dynamin K44A mutant or of wild-type beta-arrestin 1 or 2. The outcomes on the FSH-R internalization were assayed by measuring 125I-FSH binding at the cell surface when compared to internalized 125I-FSH binding. The resulting ERK phosphorylation level was visualized by Western blot analysis.

Results

In HEK 293 cells, FSH stimulated ERK phosphorylation in a dose-dependent manner. Co-transfection of the beta- arrestin (319–418) construct, or of the dynamin K44A mutant reduced FSH-R internalization in response to FSH, without affecting ERK phosphorylation. Likewise, overexpression of wild-type beta-arrestin 1 or 2 significantly increased the FSH-R internalization level in response to FSH, without altering FSH-induced ERK phosphorylation.

Conclusion

From these results, we conclude that the FSH-R does not require beta-arrestin- nor dynamin-mediated internalization to initiate ERK phosphorylation in response to FSH.
Quantitative estimation of Nipah virus replication kinetics in vitro
Authors: Chang Li-Yen , Mohd Ali AR , Hassan Sharifah Syed , AbuBakar Sazaly
Published: June 2006

Background

Nipah virus is a zoonotic virus isolated from an outbreak in Malaysia in 1998. The virus causes infections in humans, pigs, and several other domestic animals. It has also been isolated from fruit bats. The pathogenesis of Nipah virus infection is still not well described. In the present study, Nipah virus replication kinetics were estimated from infection of African green monkey kidney cells (Vero) using the one-step SYBR® Green I-based quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) assay.

Results

The qRT-PCR had a dynamic range of at least seven orders of magnitude and can detect Nipah virus from as low as one PFU/μL. Following initiation of infection, it was estimated that Nipah virus RNA doubles at every ~40 minutes and attained peak intracellular virus RNA level of ~8.4 log PFU/μL at about 32 hours post-infection (PI). Significant extracellular Nipah virus RNA release occurred only after 8 hours PI and the level peaked at ~7.9 log PFU/μL at 64 hours PI. The estimated rate of Nipah virus RNA released into the cell culture medium was ~0.07 log PFU/μL per hour and less than 10% of the released Nipah virus RNA was infectious.

Conclusion

The SYBR® Green I-based qRT-PCR assay enabled quantitative assessment of Nipah virus RNA synthesis in Vero cells. A low rate of Nipah virus extracellular RNA release and low infectious virus yield together with extensive syncytial formation during the infection support a cell-to-cell spread mechanism for Nipah virus infection.
Members of the Hyposoter didymator Ichnovirus repeat element gene family are differentially expressed in Spodoptera frugiperda
Authors: Galibert L , Devauchelle G , Cousserans F , Rocher J , Cérutti P , Barat-Houari M , Fournier P , Volkoff AN
Published: June 2006

Background

The abundance and the conservation of the repeated element (rep) genes in Ichnoviruses genomes suggest that this gene family plays an important role in viral cycles. In the Ichnovirus associated with the wasp Hyposoter didymator, named HdIV, 10 rep genes were identified to date. In this work, we report a relative quantitative transcription study of these HdIV rep genes in several tissues of the lepidopteran host Spodoptera frugiperda as well as in the H. didymator wasps.

Results

The data obtained in this work indicate that, in the early phases of infection (24 hours), HdIV rep genes each display different levels of transcripts in parasitized 2nd instar or HdIV-injected last instar S. frugiperda larvae. Only one, rep1, is significantly transcribed in female wasps. Transcript levels of the HdIV rep genes were found as not correlated to their copy number in HdIV genome. Our results also show that HdIV rep genes display different tissue specificity, and that they are primarily transcribed in S. frugiperda fat body and cuticular epithelium.

Conclusion

This work is the first quantitative analysis of transcription of the ichnovirus rep gene family, and the first investigation on a correlation between transcript levels and gene copy numbers in Ichnoviruses. Our data indicate that, despite similar gene copy numbers, not all the members of this gene family are significantly transcribed 24 hours after infection in lepidopteran larvae. Additionally, our data show that, as opposed to other described HdIV genes, rep genes are little transcribed in hemocytes, thus suggesting that they are not directly associated with the disruption of the immune response but rather involved in other physiological alterations of the infected lepidopteran larva.
Genetic Variations in Radiation and Chemotherapy Drug Action Pathways Predict Clinical Outcomes in Esophageal Cancer
Authors: Wu Xifeng , Gu Jian , Wu Tsung-Teh , Swisher Stephen G. , Liao Zhongxin , Correa Arlene M. , Liu Jun , Etzel Carol J. , Amos Christopher I. , Huang Maosheng , Chiang Silvia S. , Milas Luke , Hittelman Walter N. , Ajani Jaffer A.
Published: June 2006

Purpose

Understanding how specific genetic variants modify drug action pathways may provide informative blueprints for individualized chemotherapy.

Methods

We applied a pathway-based approach to examine the impact of a comprehensive panel of genetic polymorphisms on clinical outcomes in 210 esophageal cancer patients.

Results

In the Cox proportional hazards model, MTHFR Glu429Ala variant genotypes were associated with significantly improved survival (hazard ratio [HR] = 0.56; 95% CI, 0.35 to 0.89) in patients treated with fluorouracil (FU). The 3-year survival rates for patients with the variant genotypes and the wild genotypes were 65.26% and 46.43%, respectively. Joint analysis of five polymorphisms in three FU pathway genes showed a significant trend for reduced recurrence risk and longer recurrence-free survival as the number of adverse alleles decreased (P = .004). For patients receiving platinum drugs, the MDR1 C3435T variant allele was associated with significantly reduced recurrence risk (HR = 0.25; 95% CI, 0.10 to 0.64) and improved survival (HR = 0.44; 95% CI, 0.23 to 0.85). In nucleotide excision repair genes, there was a significant trend for a decreasing risk of death with a decreasing number of high-risk alleles (P for trend = .0008). In base excision repair genes, the variant alleles of XRCC1 Arg399Gln were significantly associated with the absence of pathologic complete response (odds ratio = 2.75; 95% CI, 1.14 to 6.12) and poor survival (HR = 1.92; 95% CI, 1.00 to 3.72).

Conclusion

Several biologically plausible associations between individual single nucleotide polymorphisms and clinical outcomes were found. Our data also strongly suggest that combined pathway-based analysis may provide valuable prognostic markers of clinical outcomes.
The role of adrenergic stimulation in maintaining maximum cardiac performance in rainbow trout (Oncorhynchus mykiss) during hypoxia,hyperkalemia and acidosis at 10°C
Authors: Hanson Linda M. , Obradovich Shannon , Mouniargi Janet , Farrell Anthony P.
Published: June 2006

As rainbow trout approach exhaustion during prolonged exercise, they maintain maximum cardiac output despite the fact their venous blood, which bathes the heart, becomes hypoxic, acidotic and hyperkalemic. Because these factors are individually recognized to have detrimental inotropic and chronotropic effects on cardiac performance, we hypothesized that adrenergic stimulation is critical in maintaining maximum cardiac performance under these collectively adverse conditions in vivo. To test this hypothesis,maximum cardiac performance in the presence and absence of maximal adrenergic stimulation was assessed with in situ rainbow trout hearts using relevant hyperkalemic (5.0 mmol l–1 K+), acidotic(pH 7.5) and hypoxic challenges. With tonic adrenergic stimulation (5.0 nmol l–1 adrenaline), hearts produced only 44.8±14.6% of their normal maximum cardiac output when exposed under normoxic conditions (20 kPa) to the hyperkalemic, acidotic perfusate, indicating that in vivothere was no refuge from cardiac impairment even if venous blood was fully oxygenated. By contrast, maximum adrenergic stimulation (500 nmol l–1 adrenaline), fully protected maximum cardiac performance under hyperkalemic and acidotic conditions over a wide range of oxygen availability, from normoxia to 2.0 kPa, a venous oxygen tension close to routine values in vivo. Extending the level of hypoxia to 1.3 kPa resulted in a 43.6±2.8% decrease in maximum cardiac output, with hearts failing when tested at 1.0 kPa. Our results suggest that adrenergic stimulation of the trout heart is critical in maintaining maximum performance during prolonged swimming tests, and probably during all forms of exhaustive activity and recovery, when venous blood is hyperkalemic, acidotic and hypoxic.
Hot limpets: predicting body temperature in a conductance-mediated thermal system
Authors: Denny Mark W. , Harley Christopher D. G.
Published: June 2006

Living at the interface between the marine and terrestrial environments,intertidal organisms may serve as a bellwether for environmental change and a test of our ability to predict its biological consequences. However, current models do not allow us to predict the body temperature of intertidal organisms whose heat budgets are strongly affected by conduction to and from the substratum. Here, we propose a simple heat-budget model of one such animal,the limpet Lottia gigantea, and test the model against measurements made in the field. Working solely from easily measured physical and meteorological inputs, the model predicts the daily maximal body temperatures of live limpets within a fraction of a degree, suggesting that it may be a useful tool for exploring the thermal biology of limpets and for predicting effects of climate change. The model can easily be adapted to predict the temperatures of chitons, acorn barnacles, keyhole limpets, and encrusting animals and plants.
Thermal stress on intertidal limpets: long-term hindcasts and lethal limits
Authors: Denny Mark W. , Miller Luke P. , Harley Christopher D. G.
Published: June 2006

When coupled with long-term meteorological records, a heat-budget model for the limpet, Lottia gigantea, provides a wealth of information regarding environmental and topographic controls of body temperature in this ecologically important species. (1) The maximum body temperature predicted for any site (37.5°C) is insufficient to kill all limpets, suggesting that acute thermal stress does not set an absolute upper limit to the elevation of L. gigantea on the shore. Therefore, the upper limit must be set by behavioral responses, sublethal effects or ecological interactions. (2)Temperatures sufficient to kill limpets are reached at only a small fraction of substratum orientations and elevations and on only three occasions in 5 years. These rare predicted lethal temperatures could easily be missed in field measurements, thereby influencing the interpretation of thermal stress.(3) Body temperature is typically higher than air temperature, but maximum air temperature can nonetheless be used as an accurate predictor of maximum body temperature. Warmer air temperatures in the future may thus cause increased mortality in this intertidal species. Interpretation of the ecological effects of elevated body temperature depends strongly on laboratory measurements of thermal stress, highlighting the need for additional research on the temporal and spatial variability of thermal limits and sublethal stress. The lengthy time series of body temperatures calculated from the heat-budget model provides insight into how these physiological measurements should be conducted.
Silken toolkits: biomechanics of silk fibers spun by the orb web spiderArgiope argentata(Fabricius 1775)
Authors: Blackledge Todd A. , Hayashi Cheryl Y.
Published: June 2006

Orb-weaving spiders spin five fibrous silks from differentiated glands that contain unique sets of proteins. Despite diverse ecological functions, the mechanical properties of most of these silks are not well characterized. Here,we quantify the mechanical performance of this toolkit of silks for the silver garden spider Argiope argentata. Four silks exhibit viscoelastic behaviour typical of polymers, but differ statistically from each other by up to 250% in performance, giving each silk a distinctive suite of material properties. Major ampullate silk is 50% stronger than other fibers, but also less extensible. Aciniform silk is almost twice as tough as other silks because of high strength and extensibility. Capture spiral silk, coated with aqueous glue, is an order of magnitude stretchier than other silks. Dynamic mechanical properties are qualitatively similar, but quantitatively vary by up to 300% among silks. Storage moduli are initially nearly constant and increase after fiber yield, whereas loss tangents reach maxima of 0.1–0.2 at the yield. The remarkable mechanical diversity of Argiope argentata silks probably results in part from the different molecular structures of fibers and can be related to the specific ecological role of each silk. Our study indicates substantial potential to customize the mechanics of bioengineered silks.
Functional evidence for the presence of a carbonic anhydrase repressor in the eyestalk of the euryhaline green crabCarcinus maenas
Authors: Henry Raymond P.
Published: June 2006

Carbonic anhydrase (CA) activity and relative expression of CA mRNA were measured in the gills of the euryhaline green crab Carcinus maenas in response to eyestalk ablation (ESA), injection of eyestalk extract and exposure to low salinity. For crabs acclimated to 32 p.p.t. salinity, ESA alone resulted in an increase in both CA activity and relative mRNA expression in the posterior, ion-transporting gills, but not in the anterior, respiratory gills. The ESA-stimulated increase in CA activity was abolished by injections of extracts of eyestalks taken from crabs acclimated to 32 p.p.t. salinity. Transfer of intact crabs from 32 to 10 p.p.t. salinity for 7 days resulted in an eightfold increase in CA activity and a sixfold increase in mRNA expression in posterior gills. ESA potentiated the normal low salinity-mediated CA induction by 23%. Daily injections of eyestalk extract reduced low salinity-stimulated CA induction by nearly 50% in intact crabs and by almost 75% in eyestalk ablated crabs. A 4-day transfer to 10 p.p.t. salinity also caused significant increases in both CA activity and mRNA expression in posterior gills, and ESA resulted in a 32% increase in the normal degree of CA induction. Daily injections of eyestalk extracts reduced CA induction in a dose-dependent manner over the 4-day time course. When CA induction was reduced by 66%, hemolymph osmotic regulation was also disrupted. These results are functional evidence for the presence of a CA repressor in the major endocrine complex of the crab, the eyestalk. This compound appears to function in keeping CA expression at low, baseline levels in crabs at high salinity. Exposure to low salinity removes the effects of the putative repressor,allowing CA expression, and thus CA activity, to increase.
Hydrolysis Kinetics of trans(O)-Bromo, Chloro or Nitro-(3,6,9-Triazaundecanedioato)cobalt(III) Complex
Authors: Kitamura Yoichi , Muneta Hiroyuki , Watanabe Kiyokatsu
Published: June 2006

For the acid-uncatalyzed aquation of trans(O)-[Co(taud)X] at the ionic strength (μ) of 0.1 (NaClO4), the first order rate constant (kaq) is 9.6 × 10−5 s−1 at 25 °C, ΔH‡ = 93 kJ mol−1, ΔS‡ = −10 J K−1 mol−1, ΔV‡ = −3.2 cm3 mol−1 with X = Cl−; and kaq is 4.6 × 10−4s−1 at 25 °C, ΔH‡ = 91 kJ mol−1, ΔS‡ = −4 J K−1 mol−1, ΔV‡ = −2.3 cm3 mol−1 with X = Br−. Here taud stands for the quinquedentate −OOCCH2NH(CH2)2NH(CH2)2NHCH2COO−. These magnitudes of ΔV‡ are slightly different from the expected values. For the acid-catalyzed aquation of trans-(O)-[Co(taud)NO2], kaq/s−1 depends on the [H+]/M of the solution: kaq = 1.3 × 10−4[H+] + 3.09 × 10−3[H+]2 at 45.6 °C and μ = 0.5 (M = mol dm−3). For the base hydrolysis of trans(O)-[Co(taud)X] at μ = 1.0 (NaClO4), the second order rate constant (k2) is 104 M−1 s−1 at 25 °C, ΔH‡ = 77 kJ mol−1, ΔS‡ = 12 J K−1 mol−1 with X = Cl−; and k2 is 760 M−1 s−1 at 25 °C, ΔH‡ = 79 kJ mol−1, ΔS‡ = 36 J K−1 mol−1 with X = Br−. The ΔV‡ ’s at μ ≈ 0 are 19.1 cm3 mol−1 with X = Cl− and 19.7 cm3 mol−1 with X = Br−. In the base hydrolysis with excess NaOH at μ = 1.0, the pseudo-first-order rate constant (kobsd) departs slightly positively from the proportionality to the [OH−] at 0.3 M < [OH−]. This type of nonlinearity has rarely been reported for the base hydrolysis of a cobalt(III) complex. The magnitudes of the activation volume for the base hydrolysis are in line with the SN1 CB mechanism. Therefore, the mechanism may be the SN1 CB mechanism, where an additional minor pathway via the second deprotonation from the taud ligand or via a hydroxide adduct formation to the carbonyl group of the taud ligand also participates.
Preparation of (Alkaneimidoyl)lanthanides and Their Reactions with Carbonyl Compounds
Authors: Murakami Masahiro , Ito Hajime , Ito Yoshihiko
Published: June 2006

The preparation of (alkaneimidoyl)lanthanide(III) reagents and their reactions with carbonyl compounds were studied. Alkyllithium was added to a mixture of an anhydrous lanthanide salt and 2,6-xylyl isocyanide in tetrahydrofuran at −78 °C. Among a series of lanthanide salts, CeCl3 effected the quantitative conversion of the isocyanide to afford an orange solution of (alkaneimidoyl)cerium(III). Although LaCl3, SmI3, and Sm(OTf)3 were found to be highly reactive, multiple insertion of the isocyanide ensued. (Alkaneimidoyl)cerium(III) could also be prepared by the reaction of dialkylmagnesium with CeCl3 and 2,6-xylyl isocyanide at −45 °C. The thus-prepared (alkaneimidoyl)cerium(III) reacted with a carbonyl compound to afford an addition product, i.e., an α-hydroxy imine. The present reactions for the preparation of (alkaneimidoyl)cerium(III) provide a convenient synthetic equivalent to a nucleophilic acyllanthanide species with a wide variation for the acyl group.
Interfacial Adsorption and Ion-Association Extraction of Protonated Tetraphenylporphyrin and Octaethylporphyrin
Authors: Chida Yoshito , Watarai Hitoshi
Published: June 2006

Protonation of tetraphenylporphyrin (TPP) and octaethylporphyrin (OEP) in toluene/acid systems was investigated by a high-speed stirring method. In toluene/sulfuric acid system, the adsorption of the diprotonated TPP and the monoprotonated OEP at the liquid–liquid interface was found, while in other acid systems including hydrochloric acid, perchloric acid, and trichloroacetic acid, the ion-association extraction of H2TPP2+ and HOEP+ was observed as well, depending on the nature of the counter anions and the concentration of the acids. An inverted correlation was suggested between the adsorption constants of the protonated porphyrins and the extraction constants of the acids with the porphyrins.
Intercalation of Water in a Layered Perovskite Compound, NaEuTiO4
Authors: Toda Kenji , Kameo Yutaka , Kurita Satoru , Sato Mineo
Published: June 2006

Intercalation of water was observed in a layered perovskite compound, NaEuTiO4, leading to its hydrated derivatives. There are some metastable intermediates in the hydrated derivatives. The hydration process includes several steps that are topotactic. The crystal structure of the hydrated derivatives was identified by Rietveld analysis for the powder X-ray diffraction pattern. It is confirmed that the water molecules are inserted into the sodium layer of NaEuTiO4.
Isolation and Spectroscopic Properties of A-β-[PV3W9O40]6− Anion Salts and Their Isomerization to the α-Isomers
Authors: Kawafune Isao , Matsubayashi Gen-etsu
Published: June 2006

β-Isomers of A-type vanadium-trisubstituted nonatungstophosphate anion salts were synthesized by a condensation of NaVO3 and A-Na9[PW9O34]·7H2O in an aqueous hydrochloric acid and 1,4-dioxane mixed solution. Their geometries were characterized by IR, 31P, 51V, and 183W NMR spectroscopies. The tetrabutylammonium salt of the β-isomer, A-β-(NBun4)4H2[PV3W9O40], isomerizes to the corresponding α-isomer both in the solid state and in solution under mild conditions, which can be directly followed by FT-IR and 31P NMR spectroscopies. The kinetics of the isomerization in the solid state had a first-order rate constant at 40 °C, k1 = 2.19 × 10−7 (s−1), together with ΔH‡ = 93.3 (kJ mol−1) and ΔS‡ = −77.3 (J K−1 mol−1). On the other hand, A-β-Cs6[PV3W9O40] and A-β-(NBun4)6[PV3W9O40], which have no protons in the cation part, do not isomerize under the same conditions. The β-to-α isomerization is promoted by protonation at the bridging oxygen atom in the W–O–W bond of the polyanion.
Syntheses and Structures of a Novel Trinaphthylene Hexaimino Cryptand: Three Different Conformations of a Macrobicyclic Ligand
Authors: Sato Tadanobu , Suzuki Atsushi , Sakai Ken , Tsubomura Taro
Published: June 2006

A synthesis in good yield of a new hexaimino cryptand containing two tris(2-aminoethyl)amine moieties bridged by three naphthylene groups is reported. Ag+ and Cu+ cryptates of the ligand have also been prepared and characterized. The cryptand and cryptates have been structurally analyzed by X-ray diffraction, unveiling three different conformations. The macrobicyclic ligand has an anti conformation in the cryptand, but has a sym form in each cryptate. Although the Ag+ cryptates have a symmetric structure on the three arms, one of the three arms in the Cu+ complex shows remarkable bending. The bent conformation is intrinsic of the Cu+ complex, as indicated by X-ray analyses and MM2 calculations. The temperature dependence of the 1H NMR spectra has also been investigated, revealing fluxional behaviors of the ligand in each compound.
A Proton Conductive Coordination Polymer II. Proof of Proton Conduction of Dihydrogen Origin in [N,N′-Bis(2-hydroxyethyl)dithiooxamidatocopper(II)] by Protodes
Authors: Kanda Seiichi , Yamamoto Fumio
Published: June 2006

An example of proton conduction in a coordination polymer was examined. Dependence of the specific conductivity on hydrogen pressure was quite strong in the title compound with a few types of protodes. The mechanism of electric conduction of this coordination polymer is discussed in connection with related phenomena of the same compound.
Gram-Order Preparation of 30Si-Enriched Silica and Silicon Powders by Means of IRMPD of Disilicon Hexafluoride
Authors: Tanaka Kazunori , Isomura Shohei , Kaetsu Hayato , Yatsurugi Yoshifumi , Hashimoto Masanori , Togashi Kazuya , Arai Shigeyoshi
Published: June 2006

Powder silica and elemental silicon enriched with 30Si were prepared at the request of nuclear physicists who had needed the isotopic samples for their research on neutron-rich nuclei. The enrichment of 30Si was performed by means of the IRMPD of Si2F6 to SiF4 using a CO2 laser. The 30Si-enriched SiF4 was further converted either to silica by hydrolysis with aqueous ammonia or to silicon by LiAlH4 reduction to SiH4 followed by its thermal decomposition. As the final products we obtained 11.35 g of silica with 20.6% 30Si, and 3.06 g of silicon with 17.5% 30Si.
Biosynthesis of Polyester Blends by Pseudomonas sp. 61-3 from Alkanoic Acids
Authors: Kato Mikiya , Fukui Toshiaki , Doi Yoshiharu
Published: June 2006

Pseudomonassp. 61-3 accumulated poly(3-hydroxyalkanoates), P(3HA), in nitrogen-free media containing medium- and long-chain alkanoic acids or plant oils. The polyesters of 3HA units of even carbon numbers ranging from C4 to C12 were produced from the alkanoic acids of even carbon numbers, while those produced from the alkanoic acids of odd carbon numbers contained 3-hydroxybutyrate (3HB) and 3HA units of odd carbon numbers of C5 to C11. The strain produced simultaneously P(3HB) homopolymer and a random copolymer of 3HA units of C4 to C12 within cells from the alkanoic acids of even carbon numbers, while a copolymer of 3HB and 3-hydroxyvalerate was formed with a random copolymer of 3HA units from the alkanoic acids of odd carbon numbers. The results suggest that Pseudomonas sp. 61-3 has two types of PHA synthases with different substrate specificities.
Organic Compounds from Insoluble Organic Matter Isolated from the Murchison Carbonaceous Chondrite by Heating Experiments
Authors: Komiya Masatoshi , Shimoyama Akira
Published: June 2006

Insoluble organic matter isolated by an HF/HCl treatment of the Murchison carbonaceous chondrite was heated from room temperature to 800 °C at a rate of 10 °C min−1 under a helium atmosphere. Over 130 organic compounds were identified in its pyrolyzates, which mainly comprised the following two groups: (1) benzene and naphthalene, and their alkyl derivatives; and (2) sulfur-containing heterocycles and their alkyl derivatives. The relative amounts of compounds released with increasing temperature during the heating process were monitored by a mass spectrometer. Those hydrocarbons were observed mainly over a temperature range of 300—600 °C. These results are generally similar to those of Yamato-791198, an Antarctic carbonaceous chondrite which we had previously analyzed. The results indicate that aliphatic and aromatic hydrocarbons, as well as S-containing heterocycles, are the major constituents of the insoluble organic matter of Murchison. Furthermore, the results suggest that the thermal history of Murchison on its parent body was similar to that of Yamato-791198.
Solvent Extraction of Several Anions with Tetrabutylammonium Ion into 1,2-Dichloroethane and Hydration of Anions in the Organic Phase
Authors: Kusakabe Satoshi , Arai Miwa
Published: June 2006

The partition equilibrium of tetrabutylammonium salts Bu4NX, where X− is N3−, NO3−, SCN−, ClO4−, and picrate ion, has been measured between water and 1,2-dichloroethane at 298 K. The distribution ratio of these salts can be explained in terms of the extraction of an ion pair (the extraction constant is defined as Kex = [Bu4N+X−]org/[Bu4N+]aq[X−]aqf±2) and the dissociation and dimerization of the ion pairs in the organic phase. The hydration number of the salt in the organic phase, nh, seems similar among dissociated, ion-paired, and dimerized species. The free energy of phase transfer corrected for the hydration effect in the organic phase, −RT(ln Kex−nh), may be correlated with the Gibbs free energy of hydration of the anions in the aqueous phase.
Structural Effect of Phosphoric Esters Having Bulky Substituents on the Extraction of Rare Earth Elements
Authors: Yoshizuka Kazuharu , Kosaka Hiroshi , Shinohara Takaaki , Ohto Keisuke , Inoue Katsutoshi
Published: June 2006

Phosphoric esters having bis(4-ethylcyclohexyl) (D4ECHPA) and bis(4-cyclohexylcyclohexyl) (D4DCHPA) groups as the alkyl substituents were synthesized in order to investigate their selectivity in the extraction of rare earth elements from acidic nitrate media, together with the apparent molecular weights of the extractants in toluene, the acid dissociation constants and the aqueous distribution coefficients of the extractants. These extractants were found to exist as dimeric species in toluene. The acid dissociation constants of the extractants are nearly the same as that of bis(2-ethylhexyl) hydrogenphosphate (D2EHPA), which is a typical commercial acidic phosphorus extractant. The aqueous distribution coefficients of the extractants become greater in the order D4ECHPA > D2EHPA > D4DCHPA. From the concentration dependencies of the hydrogen ion and extractant on the distribution ratio of rare earth elements, it was concluded that the rare earth elements (M3+) were extracted with D4ECHPA and D4DCHPA (HR) as M(HR2)3 in the organic phase; also, the extraction equilibrium constants (Kex) were evaluated. The extraction equilibrium constants of rare earth elements become greater in the order D4DCHPA > D4ECHPA > D2EHPA. It was very noticeable that the separation factor between HoIII and GdIII, β(Ho/Gd), and β(Yb/Y) with D4ECHPA, and β(Ce/La), β(Pr/La), and β(Ho/Gd) with D4DCHPA are significantly greater than those with D2EHPA. The structural effects of the extractant on the selectivity of rare earth elements are discussed in terms of the molecular modelling. Furthermore, we found that the loading capacity of NdIII with these extractants is excellent compared with that of D2EHPA, due to preventing gelation of the organic phase.