An Alternative Interpretation of the Magnetic Penetration Depth Data on Pr(2-x)Ce(x)CuO(4-y) and La(2-x)Ce(x)CuO(4-y)

We have revisited the magnetic penetration depth data on the electron-doped cuprates Pr(2-x)Ce(x)CuO(4-y) and La(2-x)Ce(x)CuO(4-y). It is proposed that the transition between the nodal-gap-like and nodeless-gap-like behaviors upon electron-doping [see, e.g., M. Kim et al., Phys. Rev. Lett. 91, 87001 (2003)] can be due to a scattering of the quasiparticles in the d-wave superconducting state by an incipient or weak antiferromagnetic spin-density-wave. This conjecture is supported by the inelastic neutron scattering and angle-resolved photoemission experiments on some closely related electron-doped cuprates.Comment: 6 pages, 5 figure

{2,2′-[(Benzyl­aza­nedi­yl)dimethylene]diphenolato}(methano­lato)boron

The title compound, C22H22BNO3, was unintentionally obtained from salicyl­aldehyde benzyl­amine and sodium borohydride. The B—O bond lengths lie in the range 1.425 (2)–1.463 (2) Å, and B—N = 1.641 (2) Å. In the crystal, weak inter­molecular C—H⋯O hydrogen bonds link the mol­ecules into chains in the [010] direction

A new photobioreactor for continuous microalgal production in hatcheries based on external-loop airlift and swirling flow

This study deals with the scale of a new photobioreactor for continuous microalgal production in hatcheries. The combination of the state-of-art with the constraints inherent to hatcheries has turned the design into a closed, artificially illuminated and external-loop airlift configuration based on a succession of elementary modules, each one being composed of two transparent vertical interconnected columns. The liquid circulation is ensured pneumatically (air injections) with respect to a swirling motion (tangential inlets). A single module of the whole photobioreactor was built-up to investigate how parameters, such as air sparger type, gas flow rate, tangential inlet, column radius and height can influence radiative transfer, hydrodynamics, mass transfer and biological performances. The volumetric productivities were predicted by modeling radiative transfer and growth of Isochrysis affinis galbana (clone Tahiti). The hydrodynamics of the liquid phase was modeled in terms of global flow behavior (circulation and mixing times, Péclet number) and of swirling motion decay along the column (Particle Image Velocimetry). The aeration performances were determined by overall volumetric mass transfer measurements. Continuous cultures of Isochrysis affinis galbana (clone Tahiti) were run in two geometrical configurations, generating either an axial or a swirling flow. Lastly, the definitive options of design are presented as well as a 120 Liter prototype, currently implemented in a French mollusk hatchery and commercialized

Geometric Phase and Helicity Inversion of Photons Propagating inside a Noncoplanarly Curved Optical Fiber

The Letter presents an exact expression for the non-adiabatic non-cyclic geometric phase of photons propagating inside a noncoplanarly curved optical fiber by using the Lewis-Riesenfeld invariant theory. It is shown that the helicity inversion of photons arises in the curved fiber. Since we have exactly solved the time-dependent Schr\"{o}dinger equation that governs the propagation of photons in a curved fiber and, moreover, the chronological product is not involved in this exact solution, our formulation therefore has several advantages over other treatments based on the classical Maxwell's theory and the Berry's adiabatic quantum theory. The potential application of helicity inversion of photons to information science is briefly suggested.Comment: 8 pages, Latex. accepted by Phys. Lett.

Cayley Trees and Bethe Lattices, a concise analysis for mathematicians and physicists

We review critically the concepts and the applications of Cayley Trees and Bethe Lattices in statistical mechanics in a tentative effort to remove widespread misuse of these simple, but yet important - and different - ideal graphs. We illustrate, in particular, two rigorous techniques to deal with Bethe Lattices, based respectively on self-similarity and on the Kolmogorov consistency theorem, linking the latter with the Cavity and Belief Propagation methods, more known to the physics community.Comment: 10 pages, 2 figure

αV-Integrins Are Required for Mechanotransduction in MDCK Epithelial Cells

The properties of epithelial cells within tissues are regulated by their immediate microenvironment, which consists of neighboring cells and the extracellular matrix (ECM). Integrin heterodimers orchestrate dynamic assembly and disassembly of cell-ECM connections and thereby convey biochemical and mechanical information from the ECM into cells. However, the specific contributions and functional hierarchy between different integrin heterodimers in the regulation of focal adhesion dynamics in epithelial cells are incompletely understood. Here, we have studied the functions of RGD-binding αV-integrins in a Madin Darby Canine Kidney (MDCK) cell model and found that αV-integrins regulate the maturation of focal adhesions (FAs) and cell spreading. αV-integrin-deficient MDCK cells bound collagen I (Col I) substrate via α2β1-integrins but failed to efficiently recruit FA components such as talin, focal adhesion kinase (FAK), vinculin and integrin-linked kinase (ILK). The apparent inability to mature α2β1-integrin-mediated FAs and link them to cellular actin cytoskeleton led to disrupted mechanotransduction in αV-integrin deficient cells seeded onto Col I substrate

Feasibility of diffusion and probabilistic white matter analysis in patients implanted with a deep brain stimulator.

Deep brain stimulation (DBS) for Parkinson\u27s disease (PD) is an established advanced therapy that produces therapeutic effects through high frequency stimulation. Although this therapeutic option leads to improved clinical outcomes, the mechanisms of the underlying efficacy of this treatment are not well understood. Therefore, investigation of DBS and its postoperative effects on brain architecture is of great interest. Diffusion weighted imaging (DWI) is an advanced imaging technique, which has the ability to estimate the structure of white matter fibers; however, clinical application of DWI after DBS implantation is challenging due to the strong susceptibility artifacts caused by implanted devices. This study aims to evaluate the feasibility of generating meaningful white matter reconstructions after DBS implantation; and to subsequently quantify the degree to which these tracts are affected by post-operative device-related artifacts. DWI was safely performed before and after implanting electrodes for DBS in 9 PD patients. Differences within each subject between pre- and post-implantation FA, MD, and RD values for 123 regions of interest (ROIs) were calculated. While differences were noted globally, they were larger in regions directly affected by the artifact. White matter tracts were generated from each ROI with probabilistic tractography, revealing significant differences in the reconstruction of several white matter structures after DBS. Tracts pertinent to PD, such as regions of the substantia nigra and nigrostriatal tracts, were largely unaffected. The aim of this study was to demonstrate the feasibility and clinical applicability of acquiring and processing DWI post-operatively in PD patients after DBS implantation. The presence of global differences provides an impetus for acquiring DWI shortly after implantation to establish a new baseline against which longitudinal changes in brain connectivity in DBS patients can be compared. Understanding that post-operative fiber tracking in patients is feasible on a clinically-relevant scale has significant implications for increasing our current understanding of the pathophysiology of movement disorders, and may provide insights into better defining the pathophysiology and therapeutic effects of DBS

Levels of genetic polymorphism: marker loci versus quantitative traits

Species are the units used to measure ecological diversity and alleles are the units of genetic diversity. Genetic variation within and among species has been documented most extensively using allozyme electrophoresis. This reveals wide differences in genetic variability within, and genetic distances among, species, demonstrating that species are not equivalent units of diversity. The extent to which the pattern observed for allozymes can be used to infer patterns of genetic variation in quantitative traits depends on the forces generating and maintaining variability. Allozyme variation is probably not strictly neutral but, nevertheless, heterozygosity is expected to be influenced by population size and genetic distance will be affected by time since divergence. The same is true for quantitative traits influenced by many genes and under weak stabilizing selection. However, the limited data available suggest that allozyme variability is a poor predictor of genetic variation in quantitative traits within populations. It is a better predictor of general phenotypic divergence and of postzygotic isolation between populations or species, but is only weakly correlated with prezygotic isolation. Studies of grasshopper and planthopper mating signal variation and assortative mating illustrate how these characters evolve independently of general genetic and morphological variation. The role of such traits in prezygotic isolation, and hence speciation, means that they will contribute significantly to the diversity of levels of genetic variation within and among species