I have developed "tennis elbow" from lugging this book around the past four weeks, but it is worth the pain, the effort, and the aspirin. It is also worth the (relatively speaking) bargain price. Including appendixes, this book contains 894 pages of text. The entire panorama of the neural sciences is surveyed and examined, and it is comprehensive in its scope, from genomes to social behaviors. The editors explicitly state that the book is designed as "an introductory text for students of biology, behavior, and medicine," but it is hard to imagine any audience, interested in any fragment of neuroscience at any level of sophistication, that would not enjoy this book. The editors have done a masterful job of weaving together the biologic, the behavioral, and the clinical sciences into a single tapestry in which everyone from the molecular biologist to the practicing psychiatrist can find and appreciate his or

Principles of Neural Science

Detector systems introduce distortions into acquired data. To obtain accurate angle and intensity information, it is necessary to calibrate, and apply corrections. Intensity non-linearity, spatial distortion, and non-uniformity of intensity response, are the primary considerations. It is better to account for the distortions within scientific analysis software, but often it is more practical to correct the distortions to produce ‘idealised’ data. Calibration methods and software have been developed for single crystal diffraction experiments, using both approaches. For powder diffraction experiments the additional task of converting a two-dimensional image to a one-dimensional spectrum is used to allow Rietveld analysis. This task may be combined with distortion correction to produce intensity information and error estimates. High-pressure experiments can introduce additional complications and place new demands on software. Flexibility is needed to be able to integrate different angular regions se...

Two-dimensional detector software: From real detector to idealised image or two-theta scan

Biological materials: Structure and mechanical properties

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New approaches to nanofabrication: molding, printing, and other techniques.

REVIEW High-efficiency light-emitting diodes emitting amber, green, blue, and ultraviolet light have been obtained through the use of an InGaN active layer instead of a GaN active layer. The localized energy states caused by In composition fluctuation in the InGaN active layer are related to the high efficiency of the InGaN-based emitting devices. The blue and green InGaN quantum-well structure light-emitting diodes with luminous efficiencies of 5 and 30 lumens per watt, respectively, can be made despite the large number of threading dislocations (1 x 10(8) to 1 x 10(12) cm-2). Epitaxially laterally overgrown GaN on sapphire reduces the number of threading dislocations originating from the interface of the GaN epilayer with the sapphire substrate. InGaN multi-quantum-well structure laser diodes formed on the GaN layer above the SiO2 mask area can have a lifetime of more than 10,000 hours. Dislocations increase the threshold current density of the laser diodes.

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The Roles of Structural Imperfections in InGaN-Based Blue Light-Emitting Diodes and Laser Diodes

In this letter we demonstrate that the anomalously low (002) x‐ray rocking curve widths for epitaxial hexagonal GaN films on (001) sapphire are a result of a specific threading dislocation (TD) geometry. Epitaxial GaN films were grown on c‐plane sapphire by atmospheric pressure metalorganic chemical vapor deposition (MOCVD) in a horizontal flow reactor. Films were grown with (002) rocking curves (ω‐scans) widths as low as 40 arcsec and threading dislocation densities of ∼2×1010 cm−2. The threading dislocations in this film lie parallel to the [001] direction and within the limit of imaging statistics, all are pure edge with Burgers vectors parallel to the film/substrate interface. These TDs will not distort the (002) planes. However, distortion of asymmetric planes, such as (102), is predicted and confirmed in (102) rocking curve widths of 740 arcsec. These results are compared with films with (002) rocking curves of ∼270 arcsec and threading dislocation densities of ∼7×108 cm−2.

Role of threading dislocation structure on the x‐ray diffraction peak widths in epitaxial GaN films

Analyses of biopolymer/calcium carbonate composites grown on inorganic abiotic substrates implanted between the shell and the shell-secreting epithelium of live red abalones (Haliotis rufescens) provide detailed spatial and temporal data on the in vivo assembly process that generates the shell. X-ray diffraction and scanning electron microscopy analyses of the growth of these flat pearl composites reveal that biomineralization is initiated by the deposition of an organic sheet on the implanted substrate, followed by the growth of a calcite layer with preferred {10.4} orientation and, finally, by the growth of nacreous aragonite. The calcite layer is structurally similar to the green organic/calcite heterolayer of native shell nacre. It comprises 0.2−2.0-μm-diameter elongated crystallites of typical geological habits in various aggregate arrangements. The shell also contains an external layer of (00.1)-oriented prismatic calcite, which is deposited on one edge of a flat pearl and has a morphology similar t...

Critical Transitions in the Biofabrication of Abalone Shells and Flat Pearls

We describe a distinct type of spontaneous hierarchical self-assembly of cytoskeletal filamentous actin (F-actin), a highly charged polyelectrolyte, and cationic lipid membranes. On the mesoscopic length scale, confocal microscopy reveals ribbonlike tubule structures that connect to form a network of tubules on the macroscopic scale (more than 100 micrometers). Within the tubules, on the 0.5- to 50-nanometer length scale, x-ray diffraction reveals an unusual structure consisting of osmotically swollen stacks of composite membranes with no direct analog in simple amphiphilic systems. The composite membrane is composed of three layers, a lipid bilayer sandwiched between two layers of actin, and is reminiscent of multilayered bacterial cell walls that exist far from equilibrium. Electron microscopy reveals that the actin layer consists of laterally locked F-actin filaments forming an anisotropic two-dimensional tethered crystal that appears to be the origin of the tubule formation.

https://science.sciencemag.org/content/sci/288/5473/2035.full.pdf

Hierarchical self-assembly of F-actin and cationic lipid complexes: stacked three-layer tubule networks.

A simple hybrid design has been developed to produce practically scatterless aperture slits for small-angle X-ray scattering and high-resolution X-ray diffraction The hybrid slit consists of a rectangular single-crystal substrate (eg Si or Ge) bonded to a high-density metal base with a large taper angle (> 10°) The beam-defining single-crystal tip is oriented far from any Bragg peak position with respect to the incident beam and hence produces none of the slit scattering commonly associated with conventional metal slits It has been demonstrated that the incorporation of the scatterless slits leads to a much simplified design in small-angle X-ray scattering instruments employing only one or two apertures, with dramatically increased intensity (a threefold increase observed in the test setup) and improved low-angle resolution

Youli Li

Papers

Role of threading dislocation structure on the x‐ray diffraction peak widths in epitaxial GaN films

Critical Transitions in the Biofabrication of Abalone Shells and Flat Pearls

Hierarchical self-assembly of F-actin and cationic lipid complexes: stacked three-layer tubule networks.

Scatterless hybrid metal–single-crystal slit for small-angle X-ray scattering and high-resolution X-ray diffraction

Jumbo squid beaks: inspiration for design of robust organic composites.