C4 Dissymmetric resorcinarene derivatives: synthesis, crystal structure and micelle formation

The synthesis of a C4 dissymmetric resorcinarene tetracarboxylic acid derivative and determination of its critical micelle concentration is reported. The tetrahydroxy derivative was prepared by reduction of the tetra-acid. The low-temperature single crystal X-ray structure of the methyl ester derivative of the tetra-acid is also reported. This crystallised with two independent molecules of similar boat (flattened cone) conformation within the asymmetric unit

Using stable isotopes to detect responses to environmental change in parapatric ctenomyid rodents

Understanding how interspecific differences in a community play out in response to historical environmental changes provides a useful foundation for predicting the evolutionary and conservation outcomes of future changes in environmental conditions. Ecological studies have increasingly utilized stable isotopes to gain insights into the diets, and hence, the floristic composition that historical populations of mammals utilized. Here, we report on the use of stable isotope analyses of rodent teeth to explore the potential role that interspecific differences in response to past environmental changes have played in shaping observed differences in genetic structure between two parapatric species of ctenomyid rodents.Fil: Takenaka, R.. University of California at Berkeley; Estados UnidosFil: Miller, M.J.. University of California at Berkeley; Estados UnidosFil: Tammone, Mauro Nicolás. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Diversidad y Evolución Austral; ArgentinaFil: Lacey, E. A.. University of California at Berkeley; Estados UnidosFil: Dawson,T. E.. University of California at Berkeley; Estados Unidos96th Annual Meeting of the American Society of MammalogistsMinneapolisEstados UnidosAmerican Society of MammalogistsUniversity of Minnesot

Upper-rim acidic peptidocalixarenes as crystal growth modifiers

Calix[4]arenes functionalised at the upper rim with acidic amino acid residues are found to have a significant impact on the crystal growth of model mineral systems, calcium carbonate and barium sulphate. The aspartic acid derivative is found to be most efficacious, matching or exceeding the impact of commercial phosphonate-based scale inhibitors. In some cases, the modified morphologies are found to be similar to those induced by proteins isolated from biomineralised systems

Cryo-electron tomography of biological specimens

Cryo-electron tomography (CET) is an imaging technique capable of visualizing the three-dimensional (3-D) structure of complex viruses, cells, and tissues in hydrated state. With the current resolution of 4-5 nm, CET can resolve supramolecular complexes that are responsible for many cellular functions. This paper discusses the important considerations in CET of biological specimens and identify areas where digital signal processing can make a decisive contribution. Topics discussed include the principles of electron tomography and CET, image background and feature contrasts in CET, acquisition and alignment of projection images, reconstruction of the image volume, denoising and segmentation of tomograms, and feature recognition in cellular tomograms

Quantum circuits for spin and flavor degrees of freedom of quarks forming nucleons

We discuss the quantum-circuit realization of the state of a nucleon in the scope of simple symmetry groups. Explicit algorithms are presented for the preparation of the state of a neutron or a proton as resulting from the composition of their quark constituents. We estimate the computational resources required for such a simulation and design a photonic network for its implementation. Moreover, we highlight that current work on three-body interactions in lattices of interacting qubits, combined with the measurement-based paradigm for quantum information processing, may also be suitable for the implementation of these nucleonic spin states.Comment: 5 pages, 2 figures, RevTeX4; Accepted for publication in Quantum Information Processin

Dynamic Critical Behavior of an Extended Reptation Dynamics for Self-Avoiding Walks

We consider lattice self-avoiding walks and discuss the dynamic critical behavior of two dynamics that use local and bilocal moves and generalize the usual reptation dynamics. We determine the integrated and exponential autocorrelation times for several observables, perform a dynamic finite-size scaling study of the autocorrelation functions, and compute the associated dynamic critical exponents $z$. For the variables that describe the size of the walks, in the absence of interactions we find $z \approx 2.2$ in two dimensions and $z\approx 2.1$ in three dimensions. At the $\theta$-point in two dimensions we have $z\approx 2.3$.Comment: laTeX2e, 32 pages, 11 eps figure

MGMT methylation analysis of glioblastoma on the Infinium methylation BeadChip identifies two distinct CpG regions associated with gene silencing and outcome, yielding a prediction model for comparisons across datasets, tumor grades, and CIMP-status

The methylation status of the O6-methylguanine- DNA methyltransferase (MGMT) gene is an important predictive biomarker for benefit from alkylating agent therapy in glioblastoma. Recent studies in anaplastic glioma suggest a prognostic value for MGMT methylation. Investigation of pathogenetic and epigenetic features of this intriguingly distinct behavior requires accurate MGMT classification to assess high throughput molecular databases. Promoter methylation-mediated gene silencing is strongly dependent on the location of the methylated CpGs,

Pulsar-wind nebulae and magnetar outflows: observations at radio, X-ray, and gamma-ray wavelengths

We review observations of several classes of neutron-star-powered outflows: pulsar-wind nebulae (PWNe) inside shell supernova remnants (SNRs), PWNe interacting directly with interstellar medium (ISM), and magnetar-powered outflows. We describe radio, X-ray, and gamma-ray observations of PWNe, focusing first on integrated spectral-energy distributions (SEDs) and global spectral properties. High-resolution X-ray imaging of PWNe shows a bewildering array of morphologies, with jets, trails, and other structures. Several of the 23 so far identified magnetars show evidence for continuous or sporadic emission of material, sometimes associated with giant flares, and a few possible "magnetar-wind nebulae" have been recently identified.Comment: 61 pages, 44 figures (reduced in quality for size reasons). Published in Space Science Reviews, "Jets and Winds in Pulsar Wind Nebulae, Gamma-ray Bursts and Blazars: Physics of Extreme Energy Release