bluuebunny/crossref_metadata_2025 huggingface dataset:
Linear and nonlinear instability waves in spatially developing two-phase mixing layers
Authors: Cheung Lawrence C. , Zaki Tamer A.
Published: May 2010

Two-phase laminar mixing layers are susceptible to shear-flow and interfacial instabilities, which originate from infinitesimal disturbances. Linear stability theory has successfully described the early stages of instability. In particular, parallel-flow linear analyses have demonstrated the presence of mode competition, where the dominant unstable mode can vary between internal and interfacial modes, depending on the flow parameters. However, the dynamics of two-phase mixing layers can be sensitive to additional factors, such as the spreading of the mean flow. In addition, beyond the early linear stage, the amplitude of the instability waves becomes finite and nonlinear effects become appreciable. As a result, an accurate description of the evolution of the mixing layer must account for nonlinear interactions including the generation of higher harmonics of the instability waves and the modification of the mean flow. These effects are investigated herein using the framework of the nonlinear parabolized stability equations. The formulation includes nonparallel effects, nonlinear modal interactions, a coupled mean flow correction, and finite amplitude deformation of the interface. Mode competition between liquid and interfacial modes is investigated. We demonstrate that nonparallelism and streamwise evolution of the flow can significantly alter the predictions of locally parallel, linear stability analyses. This is followed by a discussion on nonlinear interactions of two- and three-dimensional instability waves. It is shown that nonlinear effects can serve dual purposes. On one hand, they can be a limiting mechanism for the growth of instability waves. On the other hand, they can destabilize high frequency, linearly stable modes, and thus lead to the generation of smaller scale features in the flow.
Fabrication of InAs/GaAs quantum dot solar cells with enhanced photocurrent and without degradation of open circuit voltage
Authors: Guimard Denis , Morihara Ryo , Bordel Damien , Tanabe Katsuaki , Wakayama Yuki , Nishioka Masao , Arakawa Yasuhiko
Published: May 2010

We report the fabrication of InAs/GaAs quantum dot solar cells (QDSCs) with enhanced photocurrent and no degradation in open circuit voltage (VOC) compared to a solar cell grown without QDs and composed solely of wetting layers. Notably, the achievement of such high VOC does not require electronic coupling. We report QDSCs with a light absorption range extended up to 1.3 μm and evidence a trade-off between VOC and QD ground-state energy. These results are of major significance to the design of high efficiency QDSCs.
Terahertz antenna based on graphene
Authors: Dragoman M. , Muller A. A. , Dragoman D. , Coccetti F. , Plana R.
Published: May 2010

We have investigated several configurations of antennas based on graphene. We show that patterned metallic dipole antennas or arrays of dipole antennas deposited on graphene highly benefit from the reversible high-resistivity-to-low-resistivity transition in graphene, tuned by a gate voltage. The radiation pattern and the efficiency of such antennas are changed via the gate voltage applied on graphene.
Toward the magnetoresistive detection of single magnetic nanoparticles: New strategies for particle detection by adjustment of sensor shape
Authors: Weddemann A. , Auge A. , Albon C. , Wittbracht F. , Hütten A.
Published: May 2010

In this work, different approaches in order to enhance the sensitivity of tunnel magnetoresistive sensors are discussed by means of finite element simulations. Several sensor layouts consisting of a free CoFeB sensing layer and a pinned bottom electrode are investigated. A decrease in the detection threshold is predicted by introducing magnetic areas at the sensor boundaries which can be easily switched due to a combined interaction of exchange contribution and stray field coupling of the layers.
Magnetic response induced by a moving dielectric slab
Authors: Wang Hailei , Zhang Xiangdong
Published: May 2010

Magnetic response or magneto-optical effect is generally caused by the interaction of light with magnetized materials or some metamaterials. In this work, an exact solution for the scatterings of electromagnetic wave by the homogeneous dielectric slab moving in an arbitrary direction is presented. We find that the magnetic response can also be achieved by the dielectric slab moving along some certain directions. Such a kind of magnetic response depends on many factors such as the moving velocity of the object, the thickness, and dielectric property of the slab. At some certain velocities and incident directions of the wave, a complete polarization conversion of the reflected wave can be obtained. This means that the polarizations of the electromagnetic wave can be manipulated through reflections by the moving dielectric materials.
Variations of the Lifshitz–van der Waals force between metals immersed in liquids
Authors: Esquivel-Sirvent R.
Published: May 2010

We present a theoretical calculation of the Lifshitz–van der Waals force between two metallic slabs embedded in a fluid, taking into account the change of the Drude parameters of the metals when in contact with liquids of different index of refraction. For the three liquids considered in this work, water, CCl3F and CBr3F the change in the Drude parameters of the metal imply a difference of up to 15% in the determination of the force at short separations. These variations in the force are larger for liquids with a higher index of refraction.
Ab initio vibrational dynamics of molecular hydrogen on graphene: An effective interaction potential
Authors: Špirko Vladimír , Rubeš Miroslav , Bludský Ota
Published: May 2010

The interaction potential confining the stretching and translational motions of a molecular hydrogen physisorbed on the graphene surface has been calculated by means of the DFT/CC approach. Using a simple adiabatic separation of the stretching and translational motions, a set of effective stretching potentials is generated by performing a “finite box” integrating over the translational degrees of freedom. The resulting potentials, forming energetically narrow bands, are used to evaluate the corresponding average stretching energies, which are in turn compared to their experimental counterparts. The mass-dependent “translational” corrections of the purely stretching potential significantly improve the theory versus experiment agreement, thus evidencing their importance in the physisorption processes. Although not fully quantitative, the DFT/CC stretching potentials seem to exhibit physically correct shapes, as their morphing by only a few parameters allows for a quantitative fitting of the observed vibrational energies in terms of the effective (mass-dependent) interaction potentials.
A computer-controlled apparatus for micrometric drop deposition at liquid surfaces
Authors: Peña-Polo Franklin , Trujillo Leonardo , Sigalotti Leonardo Di G.
Published: May 2010

A low-cost, automated apparatus has been used to perform micrometric deposition of small pendant drops onto a quiet liquid surface. The approach of the drop to the surface is obtained by means of discrete, micron-scale translations in order to achieve deposition at adiabatically zero velocity. This process is not only widely used in scientific investigations in fluid mechanics and thermal sciences but also in engineering and biomedical applications. The apparatus has been designed to produce accurate deposition onto the surface and minimize the vibrations induced in the drop by the movement of the capillary tip. Calibration tests of the apparatus have shown that a descent of the drop by discrete translational steps of ∼5.6 μm and duration of 150–200 ms is sufficient to minimize its penetration depth into the liquid when it touches the surface layer and reduce to a level of noise the vibrations transmitted to it by the translation of the dispenser. Different settings of the experimental setup can be easily implemented for use in a variety of other applications, including deposition onto solid surfaces, surface tension measurements of pendant drops, and wire bonding in microelectronics.
Site-specific electronic configurations of Fe 3d states by energy loss by channeled electrons
Authors: Tatsumi Kazuyoshi , Muto Shunsuke , Nishida Ikuo , Rusz Ján
Published: May 2010

Site-specific configurations of Fe 3d electrons in a spinel ferrite were investigated by electron energy loss spectroscopy under electron channeling conditions. Site-specific spectra were extracted by applying a multivariate curve resolution (MCR) technique to the data set. An electronic difference in the Fe sites caused by ligand field splitting of trivalent Fe was probed. This demonstrated the promise of site-specific valence and spin state analysis in spintronics applications of spinel ferrites.
Effects of Mn concentration on the ac magnetically induced heating characteristics of superparamagnetic MnxZn1−xFe2O4 nanoparticles for hyperthermia
Authors: Jeun Minhong , Moon Seung Je , Kobayashi Hiroki , Shin Hye Young , Tomitaka Asahi , Kim Yu Jeong , Takemura Yasushi , Paek Sun Ha , Park Ki Ho , Chung Kyung-Won , Bae Seongtae
Published: May 2010

The effects of Mn2+ cation concentration on the ac magnetically induced heating characteristics and the magnetic properties of superparamagnetic MnxZn1−xFe2O4 nanoparticles (SPNPs) were investigated to explore the biotechnical feasibility as a hyperthermia agent. Among the MnxZn1−xFe2O4 SPNPs, the Mn0.5Zn0.5Fe2O4 SPNP showed the highest ac magnetically induced heating temperature (ΔTac,mag), the highest specific absorption rate (SAR), and the highest biocompatibility. The higher out of phase susceptibility (χm″) value and the higher chemical stability systematically controlled by the replacement of Zn2+ cations by the Mn2+ cations on the A-site (tetrahedral site) are the primary physical reason for the promising biotechnical properties of Mn0.5Zn0.5Fe2O4 SPNP.
Microfluidic sorting with high-speed single-layer membrane valves
Authors: Abate Adam R. , Agresti Jeremy J. , Weitz David A.
Published: May 2010

Sorting is one of the most important applications of microfluidic devices; however, current sorters place specific requirements on the density, size, and electrical properties of the objects to be sorted, limiting applicability. We present widely applicable microfluidic sorting. We use high-speed single-layer membrane valves to control flows in a bifurcating channel junction, to direct the paths of objects. This allows sorting at hundreds of hertz. Moreover, since the sorting action is mechanical, it is very widely applicable—to drops, particles, and even living cells.
Synthesis of Cyclogossine B Using a Traceless Pseudoproline Turn-Inducer
Authors: Wong Michelle S. Y. , Jolliffe Katrina A.
Published: May 2010

The first synthesis of the cyclic octapeptide, cyclogossine B, has been achieved, confirming the reported structure of this natural product. Cyclization of a linear precursor containing a cysteine-derived thiazolidine as a traceless turn-inducer occurred in significantly higher yields than cyclization of the analogous alanine-containing precursor under identical conditions. Deprotection of the thiazolidine followed by desulfurization provided cyclogossine B in good overall yield, indicating that cysteine-derived pseudoprolines can be effectively used as traceless turn-inducers to facilitate the cyclization of small peptides.
N,S-Heterocyclic Carbene Complexes
Authors: Chien Sheau W. , Yen Swee K. , Hor T. S. Andy
Published: May 2010

This Review describes an important subclass of N-heterocyclic carbene complexes with thiazol-2-ylidenes ligands with only one exocyclic substituent on the thiazole ring. It highlights the synthetic, structural, and catalytic properties of these rapidly emerging complexes.
Neuroscience and the Multiple Realization of Cognitive Functions
Authors: Figdor Carrie
Published: May 2010

Many empirically minded philosophers have used neuroscientific data to argue against the multiple realization of cognitive functions in existing biological organisms. I argue that neuroscientists themselves have proposed a biologically based concept of multiple realization as an alternative to interpreting empirical findings in terms of one-to-one structure-function mappings. I introduce this concept and its associated research framework and also how some of the main neuroscience-based arguments against multiple realization go wrong.
Salmonella enterica subspecies enterica serovar Enteritidis Salmonella pathogenicity island 2 type III secretion system: role in intestinal colonization of chickens and systemic spread
Authors: Wisner Amanda L. S. , Desin Taseen S. , Koch Birgit , Lam Po-King S. , Berberov Emil M. , Mickael Claudia S. , Potter Andrew A. , Köster Wolfgang
Published: May 2010

Salmonella enterica subspecies enterica serovar Enteritidis (S. Enteritidis) has been identified as a significant cause of salmonellosis in humans. Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2) each encode a specialized type III secretion system (T3SS) that enables Salmonella to manipulate host cells at various stages of the invasion/infection process. For the purposes of our studies we used a chicken isolate of S. Enteritidis (Sal18). In one study, we orally co-challenged 35-day-old specific pathogen-free (SPF) chickens with two bacterial strains per group. The control group received two versions of the wild-type strain Sal18: Sal18 attTn7 : : tet and Sal18 attTn7 : : cat, while the other two groups received the wild-type strain (Sal18 attTn7 : : tet) and one of two mutant strains. From this study, we concluded that S. Enteritidis strains deficient in the SPI-1 and SPI-2 systems were outcompeted by the wild-type strain. In a second study, groups of SPF chickens were challenged at 1 week of age with four different strains: the wild-type strain, and three other strains lacking either one or both of the SPI-1 and SPI-2 regions. On days 1 and 2 post-challenge, we observed a reduced systemic spread of the SPI-2 mutants, but by day 3, the systemic distribution levels of the mutants matched that of the wild-type strain. Based on these two studies, we conclude that the S. Enteritidis SPI-2 T3SS facilitates invasion and systemic spread in chickens, although alternative mechanisms for these processes appear to exist.
Ferrochelatase is a conserved downstream target of the blue light-sensing White collar complex in fungi
Authors: Idnurm Alexander , Heitman Joseph
Published: May 2010

Light is a universal signal perceived by organisms, including fungi, in which light regulates common and unique biological processes depending on the species. Previous research has established that conserved proteins, originally called White collar 1 and 2 from the ascomyceteNeurospora crassa, regulate UV/blue light sensing. Homologous proteins function in distant relatives ofN. crassa, including the basidiomycetes and zygomycetes, which diverged as long as a billion years ago. Here we conducted microarray experiments on the basidiomycete fungusCryptococcus neoformansto identify light-regulated genes. Surprisingly, only a single gene was induced by light above the commonly used twofold threshold. This gene,HEM15, is predicted to encode a ferrochelatase that catalyses the final step in haem biosynthesis from highly photoreactive porphyrins. TheC. neoformansgene complements aSaccharomyces cerevisiae hem15Δ strain and is essential for viability, and the Hem15 protein localizes to mitochondria, three lines of evidence that the gene encodes ferrochelatase. Regulation ofHEM15by light suggests a mechanism by whichbwc1/bwc2mutants are photosensitive and exhibit reduced virulence. We show that ferrochelatase is also light-regulated in awhite collar-dependent fashion inN. crassaand the zygomycetePhycomyces blakesleeanus, indicating that ferrochelatase is an ancient target of photoregulation in the fungal kingdom.
The Arabidopsis Mitogen-Activated Protein Kinase Phosphatase PP2C5 Affects Seed Germination, Stomatal Aperture, and Abscisic Acid-Inducible Gene Expression
Authors: Brock Anita K. , Willmann Roland , Kolb Dagmar , Grefen Laure , Lajunen Heini M. , Bethke Gerit , Lee Justin , Nürnberger Thorsten , Gust Andrea A.
Published: May 2010

Abscisic acid (ABA) is an important phytohormone regulating various cellular processes in plants, including stomatal opening and seed germination. Although protein phosphorylation via mitogen-activated protein kinases (MAPKs) has been suggested to be important in ABA signaling, the corresponding phosphatases are largely unknown. Here, we show that a member of the Protein Phosphatase 2C (PP2C) family in Arabidopsis (Arabidopsis thaliana), PP2C5, is acting as a MAPK phosphatase. The PP2C5 protein colocalizes and directly interacts with stress-induced MPK3, MPK4, and MPK6, predominantly in the nucleus. Importantly, altered PP2C5 levels affect MAPK activation. Whereas Arabidopsis plants depleted of PP2C5 show an enhanced ABA-induced activation of MPK3 and MPK6, ectopic expression of PP2C5 in tobacco (Nicotiana benthamiana) resulted in the opposite effect, with the two MAPKs salicylic acid-induced protein kinase and wound-induced protein kinase not being activated any longer after ABA treatment. Moreover, depletion of PP2C5, whose gene expression itself is affected by ABA treatment, resulted in altered ABA responses. Loss-of-function mutation in PP2C5 or AP2C1, a close PP2C5 homolog, resulted in an increased stomatal aperture under normal growth conditions and a partial ABA-insensitive phenotype in seed germination that was most prominent in the pp2c5 ap2c1 double mutant line. In addition, the response of ABA-inducible genes such as ABI1, ABI2, RD29A, and Erd10 was reduced in the mutant plants. Thus, we suggest that PP2C5 acts as a MAPK phosphatase that positively regulates seed germination, stomatal closure, and ABA-inducible gene expression.
Vascularization of testicular germ cell tumours: evidence from experimental teratocarcinomas
Authors: Silván U. , Díez‐Torre A. , Jiménez‐Rojo L. , Aréchaga J.
Published: May 2010

Testicular germ cell tumours (TGCTs) represent about 2% of male malignancies, being the most common cancer among adolescents and young adults. As in most neoplasias, TGCTs show a chaotic vascular architecture, altered blood supply and over‐expression of pro‐angiogenic factors, aspects closely related to tumour overgrowth and metastasis. Following this trend, our laboratory has analysed the effect of the hypoxic tumour microenvironment on cancer stem cells, particularly the expression of factors related to vascularization, such as matrix metalloproteinases, adhesion molecules, vascular endothelial growth factors (VEGF) and VEGF receptors. This review also summarizes our present knowledge on vascularization in the normal and neoplastic testis, the potential role of the factors involved in TGCT neovascularization and their importance as possible therapeutic targets.
Artificial neural network‐based analysis of effective crack model in concrete fracture
Authors: INCE R.
Published: May 2010

Many non‐linear fracture models have been proposed by design codes and investigators to determine fracture parameters of cement‐based materials. To characterise failure of concrete structures, the effective crack model (ECM) needs two fracture parameters: the effective crack length ae and the critical stress intensity factor . Nevertheless, ECM requires a closed‐loop testing system and the calculation of ae needs considerable computational effort. For this reason, ECM is simulated with an artificial neural network (ANN) in this study. The main benefit of using an ANN approach is that the network is built directly on experimental data by using the self‐organizing capabilities of the ANN. The presented fracture model was developed by utilising 464 noisy test data taken from the literature, which were obtained via different test methods in different laboratories. The results of an ANN‐based ECM look viable and very promising.
Wrestling with the New Economy: Judicial Rhetoric in Canadian Wrongful Dismissal Claims
Authors: Nierobisz Annette
Published: May 2010

Contemporary Law and Society scholars emphasize focused study of “law and the economy” yet empirical work on the legal implications of important economic transformations of the late twentieth century is limited. To address this issue, I analyze Canadian wrongful dismissal claims heard to judgment between 1981 and 1997 to understand how judges grappled with contradictions that arose between classic legal doctrine on the employment relationship, unstable economic conditions that limited employment opportunities for plaintiffs, and new business ideologies about employee expendability and flexibility. Findings demonstrate that judicial rhetoric was attentive to the contradictions that arose with the new economy, and unique responses were developed. These responses, however, varied according to specific socioeconomic contexts embedded within the seventeen‐year period under study. I conclude by suggesting the development of more dynamic theories of law and the economy to capture the ways in which law shifts in response to changing economic contexts.
Covering a Broad Dynamic Range: Information Processing at the Erythropoietin Receptor
Authors: Becker Verena , Schilling Marcel , Bachmann Julie , Baumann Ute , Raue Andreas , Maiwald Thomas , Timmer Jens , Klingmüller Ursula
Published: May 2010

Seeing EPO

The supply of red blood cells in mammals is controlled by the cytokine erythropoietin (EPO). In physiological situations, the concentration of EPO can change by 1000-fold.

Becker
et al.

(p.
1404
, published online 20 May) used a combination of mathematical modeling and experimental analysis to discern how cells can maintain a linear response to such a broad range of EPO concentrations. Critical features included internalization of EPO-bound receptors and subsequent degradation of the EPO ligand. Replenishment of receptors at the cell surface required a large supply of EPO receptors maintained in reserve inside the cell. These mechanisms allow cells to experience large increases in EPO concentration without becoming refractory to further stimulation.
Measurement of the Instantaneous Velocity of a Brownian Particle
Authors: Li Tongcang , Kheifets Simon , Medellin David , Raizen Mark G.
Published: May 2010

Dancing in the Light

Nearly 200 years ago, the botanist Robert Brown noted that pollen particles floating on a liquid displayed a random motion, jittering under the microscope as if the particles were alive. In 1905, Albert Einstein described this Brownian motion in terms of statistical thermodynamics. Now,

Li
et al.

(p.
1673
, published online 20 May) use a single, optically trapped silica bead to probe the dynamics of Brownian motion, measuring the predicted instantaneous velocity of the particle and verifying the short-time-scale behavior predicted a century ago. As well as testing fundamental principles of physics, the technique also has practical implications for cooling particles to ultralow temperatures.
Creation of a Bacterial Cell Controlled by a Chemically Synthesized Genome
Authors: Gibson Daniel G. , Glass John I. , Lartigue Carole , Noskov Vladimir N. , Chuang Ray-Yuan , Algire Mikkel A. , Benders Gwynedd A. , Montague Michael G. , Ma Li , Moodie Monzia M. , Merryman Chuck , Vashee Sanjay , Krishnakumar Radha , Assad-Garcia Nacyra , Andrews-Pfannkoch Cynthia , Denisova Evgeniya A. , Young Lei , Qi Zhi-Qing , Segall-Shapiro Thomas H. , Calvey Christopher H. , Parmar Prashanth P. , Hutchison Clyde A. , Smith Hamilton O. , Venter J. Craig
Published: May 2010

Let There Be Life

The DNA sequence information from thousands of genomes is stored digitally as ones and zeros in computer memory. Now,

Gibson
et al.

(p.
52
, published online 20 May; see the cover; see the Policy Forum by

Cho and Relman

) have brought together technologies from the past 15 years to start from digital information on the genome of
Mycoplasma mycoides
to chemically synthesize the genomic DNA as segments that could then be assembled in yeast and transplanted into the cytoplasm of another organism. A number of methods were also incorporated to facilitate testing and error correction of the synthetic genome segments. The transplanted genome became established in the recipient cell, replacing the recipient genome, which was lost from the cell. The reconstituted cells were able to replicate and form colonies, providing a proof-of-principle for future developments in synthetic biology.
Immunoenzyme Microscopy for Differentiating Among Systemic Bacterial Pathogens of Fish
Authors: Lewis D. H.
Published: May 2010

Immunoenzyme techniques were developed for detecting subclinical infections of Yersinia ruckeri and differentiating acute yersiniosis from motile aeromonas septicemia in channel catfish (Ictalurus punctatus). Immunoenzyme techniques were comparable to immunofluorescence and cultural procedures for detecting and differentiating Y. ruckeri and Aeromonas hydrophilia infections in catfish. The availability of immunoenzyme microscopic techniques extends immunostaining microscopy to laboratories possessing only conventional microscopes.Key words: Aeromonas hydrophila, EIA, ELISA, enteric redmouth disease, enzyme labeled antibody, fluorescent antibody, HRM, ictalurid, motile aeromonas septicemia, Yersinia ruckeri
Effects of Streamflow and Upwelling on Yield of Wild Coho Salmon (Oncorhynchus kisutch) in Oregon
Authors: Scarnecchia Dennis L.
Published: May 2010

To investigate the dependence of coho salmon (Oncorhynchus kisutch) yield on streamflow and oceanic upwelling, I regressed catch by the Oregon commercial troll fishery from 1942 to 1962 against indices of offshore upwelling the previous spring and measurements of streamflow from five Oregon coastal rivers during the freshwater rearing phase. A highly significant positive relation was found between total streamflows during the freshwater residency of the fish for the five rivers combined and the weight of the annual catch of coho salmon from 1942 to 1962. There was also a significant positive relation between total combined annual (January–December) flows for these rivers and the catch 2 yr later. Conversely, I found no significant relation between the 60 consecutive days of lowest flow during summer and catch 2 yr later. High flows during freshwater rearing probably provide more habitat and better conditions for growth and survival. I also found a significant positive relation between April through June upwelling at two stations and catch of coho salmon the following year from 1947 to 1962. Fifty-six percent of the variation in catch from 1947 to 1962 was explained by the total flows during freshwater residency, 60 consecutive days of lowest flow, plus combined April through June upwelling at both stations. It is suggested that some stocks of coho salmon smolts may move southward or remain in local offshore waters after they enter the ocean to take advantage of the production of invertebrates resulting from upwelling.Key words: streamflow, upwelling, coho salmon, Oregon coast
Dispersal and Recruitment of Zebra Mussel (Dreissena polymorpha) in a Nearshore Area in West-central Lake Erie: The Significance of Postmetamorphic Drifting
Authors: Martel André
Published: May 2010

Quantitative evidence that early postmetamorphic stages of zebra mussel (Dreissena polymorpha) can disperse in the water column and colonize substrates has been obtained using off-bottom scouring pad collectors and plankton sampling in a nearshore, shallow-water area (2–7 m) near Wheatley, Lake Erie, during August 1991. Collectors were deployed for 24–72 h, thus minimizing growth of recruits during deployments. Size criteria determined through an in situ growth experiment were used to discriminate between individuals arriving at a collector as (1) settling larvae or (2) postmetamorphic stages. During certain periods, 20–80% of individuals settling on collectors were postmetamorphic stages. Plankton samples taken near collectors also confirmed the presence of postmetamorphic stages in the water column. Most drifting juveniles ranged from about 300 μm shell length to 800 μm (some up to 1–2 mm). Although settlement by postmetamorphic stages occurred during various periods, they drifted and settled on collectors in much higher numbers during periods of strong wave action generated during storms. Colonization of natural and man-made substrates by postmetamorphic stages may be significant in exposed or turbulent areas and may impact on population dynamics. Whether postmetamorphic drifting is adaptive and which mechanisms are involved are unknown.
Spawning Mode and Reproductive Output of the Tropical Cephalopod Idiosepius pygmaeus
Authors: Lewis Andrew R. , Choat J. Howard
Published: May 2010

Reproductive biology of the tropical sepioid cephalopod Idiosepius pygmaeus was investigated in wild specimens and in individuals maintained in aquaria through the adult life span. This species produced multiple egg batches over 80% of the observable adult weight range, indicating a coordination of reproductive and somatic growth. Reproductive output was consistent within, but variable between, individuals. Oocyte synthesis and maturation occur continuously after sexual maturation has been reached. Senescence and death are not related to an exhaustion of reproductive potential. On average, captive female I. pygmaeus with access to unlimited food produced 640 eggs in 11 batches over 18 d. When reproductive output was expressed as a ratio of dry female body weight, on average, specimens had incorporated five times their body weight into eggs and egg coatings. Under food stress, captive specimens laid fewer eggs but maintained egg size and periodicity of egg laying. Food stress had no effect on either laying duration or weight at death. This study provides further evidence that terminal spawning modes are not ubiquitous amongst cephalopods.
Cell-mediated Immune Response of Rainbow Trout (Oncorhynchus mykiss) to LarvalPseudoterranova decipiens(Nematoda; Ascaridoidea) following Sensitization to Live Sealworm, Sealworm Extract, and Nonhomologous Extracts
Authors: Ramakrishna N. R. , Burt M. D. B. , MacKinnon B. M.
Published: May 2010

The delaved-type hypersensitivity (DTH) reaction (an in vivo manifestation of cell-mediated immunity) was studied in rainbow trout (Oncorhynchus mykiss) exposed to sealworm Pseudoterranova decipiens infections. Test fish immunized with sealworm extract and live intact worms, were compared with control fish which received either phosphate-buffered saline (negative control) or nonhomologous cestode or nematode antigens (positive control). Test fish immunized with sealworm extract produced a typical DTH reaction to live sealworm, challenge. The DTH reaction was similar to that in mammals and showed lymphoid and mononuclear cell infiltration. The electron microscopical studies revealed the presence of activated macrophages and plasma cells in the reaction zone. The specific response, following immunization with homologous antigens, supports the existence of T-cell function with anamnesis in rainbow trout exposed to sealworm antigens. However, when the test fish were immunized with live sealworms and later challenged with live sealworms, the secondary response was poor and showed no difference from controls and naive fish.
Changes in Erythron Organization during Prolonged Cadmium Exposure: An Indicator of Heavy Metal Stress?
Authors: Houston Arthur , Blahut Shelley , Murad Ajmal , Amirtharaj Preetha
Published: May 2010

Changes in erythron organization were examined in goldfish (Carassius auratus) exposed for 3 wk to 5, 15, and 25% of 240-h Cd LC50. In a subsequent, more extended study, specimens were first rendered acutely anemic by immersion in phenylhydrazine HCl, allowed to recover in Cd-free water or in concentrations equivalent to ~5 or ~11% of LC50, and sampled after 2, 5, 8, and 11 wk. Total, dividing, and degrading or karyorrhectic cell numbers were recorded, as were cell length, one-sided surface area, and form factor, in fish exposed to ~11% LC50, total cell numbers and the incidence of cell division fell, while karyorrhexis increased. Dividing to total cell ratios declined with time; karyorrhectic to total and karyorrhectic to dividing cell ratios increased. Variations in cytomorphology suggested slower cell maturation at both metal concentrations. Detection of heavy metal stress in fishes by this form of hematological assessment appears feasible.
Ontogenetic Changes in Prey Selection and Visual Acuity of the Yellow Perch, Perca flavescens
Authors: Wahl Christina M. , Mills Edward L. , McFarland William N. , DeGisi Joseph S.
Published: May 2010

Age-0 yellow perch, Perca flavescens, shift from pelagic to demersal waters of Oneida Lake, New York, between late June to mid-July, when they reach standard lengths of 24–31 mm. The timing of this habitat shift coincides with the size range over which yellow perch achieve a degree of visual resolution that nearly equals that of adult yellow perch, from 174 min of arc in newly hatched larvae to 9–12 min in adults. This visual improvement is reflected in the yellow perch's diet, which consists of an increasingly wider range of prey sizes and types. If twin cones are counted as functionally separate photoreceptors, there is a significant improvement of the calculated visual acuity in larval fish with lenses < 1 mm in diameter but not in older fish with larger lenses. During its rapid growth phase the most optimistic calculation of visual acuity in a young yellow perch is insufficient to explain the feeding success necessary at this time. We suggest therefore that young yellow perch spend more time in search of prey than their adult counterparts.
FINITE LINEAR QUOTIENTS OF ${\mathcal{B}}_3$ OF LOW DIMENSION
Authors: ROWELL ERIC C. , TUBA IMRE
Published: May 2010

We study the problem of deciding whether or not the image of an irreducible representation of the braid group [Formula: see text] of degree ≤ 5 has finite image if we are only given the eigenvalues of a generator. We provide a partial algorithm that determines when the images are finite or infinite in all but finitely many cases, and use these results to study examples coming from quantum groups. Our technique uses two classification theorems and the computational group theory package GAP.
THE WELL-ORDERING OF DUAL BRAID MONOID
Authors: FROMENTIN JEAN
Published: May 2010

We describe the restriction of the Dehornoy ordering of braids to the dual braid monoids introduced by Birman, Ko and Lee: we give an inductive characterization of the ordering of the dual braid monoids and compute the corresponding ordinal type. The proof consists in introducing a new ordering on the dual braid monoid using the rotating normal form of arXiv:math.GR/0811.3902, and then proving that this new ordering coincides with the standard ordering of braids.
INTERNATIONAL INEQUITY AVERSION AND THE SOCIAL COST OF CARBON
Authors: TOL RICHARD S. J.
Published: May 2010

I define the rate of inequity aversion, distinguishing between the pure rate and the consumption rate. I measure the rate of aversion to inequality in consumption as expressed in the development aid given by rich countries to poor ones between 1965 and 2005. There is an ambiguous relationship between the pure rate of inequity aversion and the consumption rate, driven by the rate of risk aversion. However, for a reasonable choice of the rate of risk aversion, rich countries are shown to be inequity averse, and increasingly so over time. The social cost of carbon is very sensitive to equity weighting and assumptions about the rate of risk and inequity aversion. Estimates of the consumption rate of inequity aversion for recent data suggest that the equity-weighted social cost of carbon is less than 50% larger than the unweighted estimate.
β1-Adrenergic receptor activation induces mouse cardiac myocyte death through both L-type calcium channel-dependent and -independent pathways
Authors: Wang Wei , Zhang Hongyu , Gao Hui , Kubo Hajime , Berretta Remus M. , Chen Xiongwen , Houser Steven R.
Published: May 2010

Cardiac diseases persistently increase the contractility demands of cardiac myocytes, which require activation of the sympathetic nervous system and subsequent increases in myocyte Ca2+ transients. Persistent exposure to sympathetic and/or Ca2+ stress is associated with myocyte death. This study examined the respective roles of persistent β-adrenergic receptor (β-AR) agonist exposure and high Ca2+ concentration in myocyte death. Ventricular myocytes (VMs) were isolated from transgenic (TG) mice with cardiac-specific and inducible expression of the β2a-subunit of the L-type Ca2+ channel (LTCC). VMs were cultured, and the rate of myocyte death was measured in the presence of isoproterenol (ISO), other modulators of Ca2+ handling and the β-adrenergic system, and inhibitors of caspases and reactive oxygen species generation. The rate of myocyte death was greater in TG vs. wild-type myocytes and accelerated by ISO in both groups, although ISO did not increase LTCC current ( ICa-L) in TG-VMs. Nifedipine, an LTCC antagonist, only partially prevented myocyte death. These results suggest both LTCC-dependent and -independent mechanisms in ISO induced myocyte death. ISO increased the contractility of wild type and TG-VMs by enhancing sarcoplasmic reticulum function and inhibiting sarco(endo)plasmic reticulum Ca2+-ATPase, Na+/Ca2+ exchanger, and CaMKII partially protected myocyte from death induced by both Ca2+ and ISO. Caspase and reactive oxygen species inhibitors did not, but β2-AR activation did, reduce myocyte death induced by enhanced ICa-L and ISO stimulation. Our results suggest that catecholamines induce myocyte necrosis primarily through β1-AR-mediated increases in ICa-L, but other mechanisms are also involved in rodents.
FGF-1 reverts epithelial-mesenchymal transition induced by TGF-β1 through MAPK/ERK kinase pathway
Authors: Ramos Carlos , Becerril Carina , Montaño Martha , García-De-Alba Carolina , Ramírez Remedios , Checa Marco , Pardo Annie , Selman Moisés
Published: May 2010

Idiopathic pulmonary fibrosis (IPF) is a progressive and lethal lung disease characterized by the expansion of the fibroblast/myofibroblast population and aberrant remodeling. However, the origin of mesenchymal cells in this disorder is still under debate. Recent evidence indicates that epithelial-mesenchymal transition (EMT) induced primarily by TGF-β1 plays an important role; however, studies regarding the opposite process, mesenchymal-epithelial transition, are scanty. We have previously shown that fibroblast growth factor-1 (FGF-1) inhibits several profibrogenic effects of TGF-β1. In this study, we examined the effects of FGF-1 on TGF-β1-induced EMT. A549 and RLE-6TN (human and rat) alveolar epithelial-like cell lines were stimulated with TGF-β1 for 72 h, and then, in the presence of TGF-β1, were cultured with FGF-1 plus heparin for an additional 48 h. After TGF-β1 treatment, epithelial cells acquired a spindle-like mesenchymal phenotype with a substantial reduction of E-cadherin and cytokeratins and concurrent induction of α-smooth muscle actin measured by real-time PCR, Western blotting, and immunocytochemistry. FGF-1 plus heparin reversed these morphological changes and returned the epithelial and mesenchymal markers to control levels. Signaling pathways analyzed by selective pharmacological inhibitors showed that TGF-β1 induces EMT through Smad pathway, while reversion by FGF-1 occurs through MAPK/ERK kinase pathway, resulting in ERK-1 phosphorylation and Smad2 dephosphorylation. These findings indicate that TGF-β1-induced EMT is reversed by FGF-1 and suggest therapeutic approaches to target this process in IPF.
The Kidney Evaluation and Awareness Program in Sheffield (KEAPS): A Community-Based Screening for Microalbuminuria in a British Population
Authors: Bello Aminu K. , Peters Jean , Wight Jeremy , El Nahas Meguid
Published: May 2010

Background/Objectives: Microalbuminuria (MA) detects subjects at risk for cardiovascular disease (CVD) and chronic kidney disease (CKD) among diabetics, hypertensives and the general population. There is still a paucity of data on prevalence and risk factors for MA in the UK. We examined in a cross-sectional study, the prevalence and risk factors for MA in the general population of Sheffield, UK. Methods: The study was conducted among participants of the Kidney Evaluation and Awareness Program in Sheffield (KEAPS), a population-based screening program for MA. The screening tools included a questionnaire collating information on demographics, lifestyle, medical and family history of diabetes mellitus, hypertension and CKD. MA measurements were obtained by immunonephelometry, and MA thresholds were defined using the albumin-creatinine ratio. Results: The prevalence of MA was 7.1% in a random sample of a Sheffield-based population screened only once. The prevalence was 6.2% in the non-diabetic and non-hypertensive subjects. The prevalence of MA was only 1.3% in the subjects without any known risk factor, such as old age, diabetes, hypertension, obesity or CVD. The prevalence of MA could be overestimated as it was based on a single albumin-creatinine ratio testing. The independent predictor variables associated with the presence of MA in a mutually adjusted logistic regression model were: age (OR = 1.012, 95% CI: 1.00–1.02), diabetes (OR = 3.25, 95% CI: 1.30–8.13), obesity (OR = 4.09, 95% CI: 1.71–9.80) and family history of hypertension (OR = 1.87, 95% CI: 1.00–3.47). Conclusions: The main determinants of MA were increased age, diabetes, obesity and family history of hypertension. On the population level, obesity as a risk factor for MA is less well documented; in this study obesity had greater odds for MA than diabetes and hypertension.
Prognostic Significance of Hyperuricemia in Patients with Different Types of Renal Dysfunction and Acute Myocardial Infarction Treated with Percutaneous Coronary Intervention
Authors: Kowalczyk Jacek , Francuz Pawel , Swoboda Ryszard , Lenarczyk Radoslaw , Sredniawa Beata , Golda Adam , Kurek Tomasz , Mazurek Michal , Podolecki Tomasz , Polonski Lech , Kalarus Zbigniew
Published: May 2010

Aim: This study evaluated the impact of hyperuricemia (HUR) on outcome in patients with different types of impaired renal function (IRF) and acute myocardial infarction (AMI) treated invasively. Methods: Out of 3,593 consecutive AMI patients treated invasively, 1,015 IRF patients were selected. The IRF group consisted of patients with baseline kidney dysfunction (BKD group) and/or patients with contrast-induced nephropathy (CIN group). HUR was defined as a serum uric acid concentration (SUAC) >420 µmol/l (>7 mg/dl). Independent predictors of death and major adverse cardiovascular events (MACE) were selected by the multivariate Cox-regression model. Results: Remote mortality rates were higher in HUR patients: IRF (32.7 vs. 18.6%), BKD (41.3 vs. 25.9%), CIN (35.4 vs. 16.7%); all p < 0.001. HUR was an independent predictor of death in BKD (hazard ratio (HR) 1.38, p < 0.05). Each 100-µmol/l increase in SUAC was associated with a significant increase of HR for mortality: 1.087 in IRF patients, 1.108 in BKD patients, 1.128 in CIN patients; all p < 0.05. Remote major adverse cardiovascular event rates were higher in HUR patients: IRF (55.4 vs. 48.9%), CIN (56.8 vs. 48%); both p < 0.05. Conclusions: In AMI patients treated invasively, an increase in SUAC is an independent predictor of death within all types of renal dysfunction; HUR defined as SUAC >420 µmol/l (>7 mg/dl) is a predictor only in BKD patients.
Utilization and Outcome of ‘Out-of-Center Hemodialysis’ in the United States: A Contemporary Analysis
Authors: MacRae Jennifer M. , Rose Caren L. , Jaber Bertrand L. , Gill John S.
Published: May 2010

Background: There is increasing interest in the delivery of out-of-center hemodialysis (HD), particularly in the home setting, but little systematic information about its use and outcome in contemporary incident patients is available. Patients and Methods: Out-of-center HD was defined as HD delivered in a residential setting, mainly at home or in a long-term care facility (such as a nursing home) irrespective of the length and frequency of therapy. All-cause mortality was determined in an observational cohort study of 458,329 adult patients initiating dialysis in the United States with Medicare as a primary payer. Results: Between 1995 and 2004, out-of-center HD was the initial modality in 1,641 (0.4%) of eligible participants, although there was significant geographic variation. Patients initiating out-of-center HD were younger, more likely to be nonwhite, had fewer comorbidities, a higher median income, and were more likely to be employed than patients initiating in-center HD or peritoneal dialysis (PD). In multivariate analysis, out-of-center HD patients had a higher overall risk of death compared to in-center HD or PD patients (HR = 1.10, 95% CI 1.04, 1.17), although the relative risk of death was lower in younger and healthier patients (HR = 0.78; 95% CI 0.61, 1.00). Conclusion: Out-of-center HD is not associated with a survival advantage among unselected patients initiating dialysis in the United States. These results call for better characterization of out-of-center HD in national registries, primarily to effectively compare the use, outcomes and potential benefits of home HD to standard therapies.
Short Communication: Asymmetric Dimethylarginine Impairs Angiogenic Progenitor Cell Function in Patients With Coronary Artery Disease Through a MicroRNA-21–Dependent Mechanism
Authors: Fleissner Felix , Jazbutyte Virginija , Fiedler Jan , Gupta Shashi K. , Yin Xiaoke , Xu Qingbo , Galuppo Paolo , Kneitz Susanne , Mayr Manuel , Ertl Georg , Bauersachs Johann , Thum Thomas
Published: May 2010

Rationale
:

The endogenous nitric oxide synthase inhibitor asymmetrical dimethylarginine (ADMA) is increased in patients with coronary artery disease and may regulate function of circulating angiogenic progenitor cells (APCs) by small regulatory RNAs.

Objectives
:

To study the role of microRNAs in ADMA-mediated impairment of APCs.

Methods and Results
:

By using microarray analyses, we established microRNA expression profiles of human APCs. We used ADMA to induce APC dysfunction and found 16 deregulated microRNAs. We focused on
miR-21
, which was 3-fold upregulated by ADMA treatment. Overexpression of
miR-21
in human APCs impaired migratory capacity. To identify regulated
miR-21
targets, we used proteome analysis, using difference in-gel electrophoresis followed by mass spectrometric analysis of regulated proteins. We found that transfection of
miR-21
precursors significantly repressed superoxide dismutase 2 in APCs, which resulted in increased intracellular reactive oxygen species concentration and impaired nitric oxide bioavailability.
MiR-21
further repressed sprouty-2, leading to Erk Map kinase–dependent reactive oxygen species formation and APC migratory defects. Small interference RNA–mediated superoxide dismutase 2 or sprouty-2 reduction also increased reactive oxygen species formation and impaired APC migratory capacity. ADMA-mediated reactive oxygen species formation and APC dysfunction was rescued by
miR-21
blockade. APCs from patients with coronary artery disease and high ADMA plasma levels displayed >4-fold elevated
miR-21
levels, low superoxide dismutase 2 expression, and impaired migratory capacity, which could be normalized by
miR-21
antagonism.

Conclusions
:

We identified a novel
miR-21
–dependent mechanism of ADMA-mediated APC dysfunction.
MiR-21
antagonism therefore emerges as an interesting strategy to improve dysfunctional APCs in patients with coronary artery disease.