Technical note: A tool for determining rotational tilt axis with or without fiducial markers

Virtually all reliable TEM tomographic reconstructions in life science depend upon cross-correlating successive images in a tilt-stack, and then using gold nanobeads as fiducial markers for determining the relative image rotation axis. Although the rotational tilt angle is one of the essential parameters affecting the quality of tomographic reconstructions, little is discussed about its determination. We provide here a simple tool based on the property of Fast Fourier Transformation for determining this rotation axis offset angle. Our method uses two publicly-available software packages (IMOD and ImageJ), and can be used on any TEM-based image stack, which is useful for images with poor bead distribution or situations where such beads are not visible. We illustrate this procedure with two different biological samples, one of which is a plunge frozen cryo-sample with fiducials and the other an epon-embedded thin section without fiducials. Prior knowledge of the rotational tilt angle facilitates further processing tomograms. With cross-correlation and the FFT-obtained rotational tilt angle, we reconstructed tomograms, of which the cross-section did not show “arc” distortion. This tool could be easily incorporated into any software for the alignment with or without fiducials.     

Classification of lightning damage to wind turbine blades

Lightning damage to wind turbine blades is of great concern to wind power installations. We investigate various issues arising from lightning damage and assess the causes through actual lightning observations as well as from high‐voltage and large‐current experiments. Although installing lightning receptors and down conductors provide a good countermeasure, blade damage can still be caused by lightning still. New techniques are needed to better protect blades from lightning surges; these may include not only better performance and layout of receptors, but also independent lightning towers and new types of blade materials. This paper provides a classification of blade damage sustained in winter lightning, ranked in severity by analyzing the many incidents of damage that have actually occurred in Japan. Moreover, a list of possible causes of damage and relative countermeasures is also presented. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Effects of feeding a calf starter on molecular adaptations in the ruminal epithelium and liver of Holstein dairy calves

The objective of this study was to elucidate the effect of feeding a calf starter on the volatile fatty acid (VFA) profile in the rumen and on expression of genes involved in epithelial intracellular pH regulation, butyrate metabolism, and hepatic urea cycle during the weaning transition. Twenty Holstein bull calves were fed either milk replacer and hay (MR) or milk replacer, hay, and a commercial texturized calf starter (MR+S) in a randomized complete block design. All calves were fed 750 g/d of milk replacer as the basal diet. Calves on the MR+S treatment were also fed starter ad libitum, and the energy intake of calves within blocks was maintained by supplementing the MR group with extra milk replacer that was equivalent to the energy intake from calf starter. Calves were killed 3 d after they consumed 680 g/d of calf starter for 3 consecutive days. Calves fed MR+S had higher VFA concentrations in the rumen (99.1±8.1 vs. 64.6±8.6 mM) and a higher molar proportion of butyrate (15.6±1.7 vs. 7.9±1.9%) than calves fed MR. Relative abundance of mRNA for monocarboxylate transporter isoform 1 was higher (1.45 vs. 0.53), and that of Na(+)/H(+) exchanger isoform 3 (0.37 vs. 0.82) and 3-hydroxy-3-methylglutaryl synthase isoform 1 (0.40 vs. 0.94) lower for the MR+S treatment compared with the MR treatment. In the liver, relative mRNA abundances of argininosuccinate synthetase isoform 1 (2.67 vs. 1.56), argininosuccinate lyase (1.44 vs. 0.99), and arginase isoform 1 (3.21 vs. 1.74) were greater for MR+S than for MR calves. Calf starter consumption appeared to increase fermentation in the rumen and affected expression of genes involved in cholesterol synthesis and intracellular pH regulation in ruminal epithelium, and those involved in urea cycle in the liver.     

Transglutaminase-mediated in situ hybridization (TransISH) system: a new methodology for simplified mRNA detection

Detection and localization of specific DNA or RNA sequences in cells and tissues are of great importance for biological research, diagnosis, and environmental monitoring. However, the most common procedure for in situ hybridization employs laborious immunostaining techniques. In the present study, we report proof-of-concept for a new RNA-enzyme conjugated probe for the detection of mRNA on tissue sections with a simple procedure. An RNA probe modified with a specific dipeptide substrate of transglutaminase was prepared. Alkaline phosphatase was then covalently and site-specifically combined to the dipeptide-labeled RNA using microbial transglutaminase. The new RNA probe labeled with alkaline phosphatase was validated by in situ hybridization (ISH) and proved to be a sensitive and sequence specific probe for mRNA detection in tissues. The new transglutaminase-mediated ISH (TransISH) strategy is free from antigen-antibody reaction, leads to one-step signal amplification after hybridization, and thus will be widely applicable for highly sensitive nucleic acid detection.     

Thermoelectric Properties of Tix(HfyZr1?y)1?xNiSn0.998Sb0.002 Half-Heusler Ribbons

Ribbons of Ti _x (Hf _y Zr_1−y )_1−x NiSn_1−z Sb _z (x = 0.1 to 1, y = 0.1 to 0.9, z = 0, 0.002, 0.004) were prepared by spin casting and annealed for 1 h at T _a = 1000 K, 1050 K, 1073 K, and 1100 K. The crystal phase of the ribbons was investigated by x-ray diffraction analysis and transmission electron microscopy. All the ribbons consisted of a phase with a half-Heusler structure. The Seebeck coefficient, electrical conductivity, thermal conductivity, power factor, and figure of merit ZT at room temperature were clarified experimentally as a function of x, y, z, and T _a. Despite the large thermal conductivity, the power factor and figure of merit were remarkably large at x = 0.5, y = 0.5, z = 0.002, and T _a = 1073 K, because the Seebeck coefficient and electrical conductivity were large.     

Microstructures and Thermoelectric Properties of an Annealed Ti<Subscript>0.5</Subscript>(Hf<Subscript>0.5</Subscript>Zr<Subscript>0.5</Subscript>)<Subscript>0.5</Subscript>NiSn<Subscript>0.998</Subscript>Sb<Subscript>0.002</Subscript> Ribbon

The thermoelectric half-Heusler compound Ti_0.5(Hf_0.5Zr_0.5)_0.5NiSn_0.998Sb_0.002 was fabricated by spin-casting and subsequent annealing. ZT at room temperature increased with annealing time through an increase in absolute Seebeck coefficients despite a decrease in electrical conductivity. ZT reached 0.10 after annealing at 1050 K for 48 h. In powder x-ray diffraction analysis, each half-Heusler peak was accompanied by a bump at the high-angle side, corresponding to a minor Ti-rich half-Heusler phase. The quantity and Ti composition of the minor phase increased with annealing time, although those of the major half-Heusler phase were almost constant. In transmission electron microscopic analysis, granular domains, several nanometers in size, with atomic ordering or disordering were observed. Thermoelectric properties were␣improved by annealing through the growth of heterogeneous microstructures of the Ti-rich and Ti-poor half-Heusler grains and of the granular domains.     

XCP-based transmission control mechanism for optical packet switched networks with very small optical RAM

According to a famous rule-of-thumb, buffer size of each output link of a router should be set to bandwidth-delay product of the network, in order to achieve high utilization with TCP flows. However, ultra high speed of optical networks makes it very hard to satisfy this rule-of-thumb, especially with limited choices of buffering in the optical domain, because optical RAM is under research and it is not expected to have a large capacity, soon. In this article, we evaluate the performance of our explicit congestion control protocol-based architecture designed for very small Optical RAM-buffered optical packet switched wavelength division multiplexing networks with pacing at edge nodes in order to decrease the required buffer size at core nodes. By using a mesh topology and applying TCP traffic, we evaluate the optical buffer size requirements of this architecture and compare with a common proposal in the literature.

Numerical Analysis of Effective Thermal Conductivity of Microwire Array Element

We have used the finite-element method to calculate numerically the equations of electrical and thermal transport. The thermal conductivity of a wire array is analyzed. The influence of the wire array on the effective thermal conductivity of the element is discussed. The effective thermal conductivity decreases as the wire diameter is reduced. Decreasing the packing density significantly reduces the effective thermal conductivity. In the classical regime, the ratio of the effective electrical conductivity to the effective thermal conductivity of the wire array can be expressed as a function of packing density; this ratio decreases as the packing density decreases. The ratio for a wire array with realistic parameters is similar to that of bulk bismuth. Therefore, to improve the thermoelectric figure of merit, it is critical to enhance the intrinsic power factor in a wire by exploiting thermomagnetic or quantum effects.