Ameloblast-lineage cells of rat tooth germs proliferate and scatter in response to hepatocyte growth factor in culture

Hepatocyte growth factor (HGF) is considered to be one of the mediators of epithelial-mesenchymal interactions during early organogenesis and to be involved in the development of murine molars. In this study, the immunohistochemical localization of HGF and of its receptor, c-Met, revealed that HGF was distributed in the proliferating mesenchymal cells in the dental papillae and that c-Met was continuously expressed in the epithelial cells during the development of rat incisors. These observations confirmed the involvement of HGF in the development of rat incisors, as demonstrated previously in molars. We then used a primary culture of ameloblast-lineage cells, prepared from mandibular incisors of young rats, to examine the direct effects of HGF on the growth and differentiation of ameloblasts. We found that HGF at 2-20 ng/ml induced a marked increase in the number of ameloblast-lineage cells and in the scattering of such cells. Our results suggest that HGF promotes the proliferation and scattering of ameloblast-lineage cells simultaneously.     

Structure of the zinc endoprotease from Streptomyces caespitosus

A zinc endoprotease produced by Streptomyces caespitosus (ScNP) specifically hydrolyzes the peptide bond at the imino side of aromatic residues and is the smallest protease found to date. Although ScNP carries the zinc-binding sequence HEXXH, its primary structure of 132 amino acid residues differs from those of other known zinc metalloendoproteases. X-ray structural analysis of ScNP at 1.6 A resolution revealed that despite a lack of sequence homology, the common topological feature of main-chain folding and a beta-turn containing methionine, which is a feature of the zinc metalloendoprotease superfamily of metzincins, is conserved in ScNP. The zinc atom of ScNP is tetrahedrally ligated by the two histidines in the HEXXH sequence, an aspartate residue and a water molecule. Thus, ScNP represents a novel subfamily of metzincins with a HEXXHXXGXXD zinc-binding sequence. A plausible substrate recognition pocket to which aromatic residues bind is located near the catalytic zinc ion.     

A case report of one-stage repair for transposition of the great arteries with intact ventricular septum and coarctation of the aorta in neonate

We report a neonatal case of one-stage repair for transposition of the great arteries with intact ventricular septum (TGA with IVS) and coarctation of the aorta (CoA). The surgery was performed at 27 days of age when the patient, a male, weighed 3408 g. Preoperative cardiac catheterization and angiography confirmed the diagnosis of TGA with IVS, CoA, atrial septal defect, patent ductus arteriosus, persistent left superior vena cava, left sided juxta-positioning of appendages and dextrocardia. The procedure was simultaneous subclavian flap aortoplasty through a left thoracotomy and an arterial switch operation through a median sternotomy. The patient's postoperative course was uneventful and he has grown well. Postoperative cardiac catheterization revealed mild pulmonary stenosis (pressure gradient of 19 mmHg between the right ventricle and the pulmonary artery) and mild aortic arch kinking from the arterial switch maneuver. One-stage repair, the combination of subclavian flap aortoplasty and arterial switch operation, provides a good clinical result in this complex malformation.     

2.8-Gb/s 176-mW byte-interleaved and 3.0-Gb/s 118-mWbit-interleaved 8:1 multiplexers with a 0.15-μm CMOS technology

This paper reports the first CMOS implementation of an 8:1 byte-interleaved multiplexer (byte-MUX) operating in the Gb/s region, together with an 8:1 bit-interleaved multiplexer (bit-MUX). A future generation 0.15-μm CMOS technology has been applied. Both chips use identical bit-MUX cores with a static shift-register architecture, and have ECL interfaces with a single supply of -2 V. The byte-MUX demonstrates 43-mW/GHz dependence on clock frequency and operates up to 2.8 Gb/s with a power dissipation of 176 mW. The bit-MUX showed 20-mW/GHz dependence on clock frequency and operated up to 3.0 Gb/s with a power dissipation of 118 mW. This revel of performance has been achieved by a novel row-column exchanger configuration, critical path reduction and precise clocking techniques utilized in the bit-MUX core, and the development of high-speed I/O buffers     

A functional motif discovery algorithm for invertebrate EST sequence data

We have developed a new algorithm for invertebrate expressed sequence tag (EST) analysis, termed as the fmEST algorithm, which consists of a systematic homology search, functional motif scanning, and clustering alignment. This study was undertaken to evaluate the validity of our fmEST algorithm in functional motif discovery for invertebrate EST sequence data. Out of 200 unidentified invertebrate ESTs, including 100 arthropod ESTs and 100 mollusk ESTs, 18 arthropod ESTs and 21 mollusk ESTs were identified as fmESTs that contained functional motifs. The nucleotide lengths of arthropod fmEST and mollusk fmEST sequences were distributed from 388 to 954 bp and from 222 to 742 bp, respectively. This result allowed us to annotate these invertebrate fmESTs as various functional genes, while they showed no significant homology to the gene information recorded in the international DNA databases using the conventional BLAST homology search program. In addition, another 1 arthropod EST and 23 mollusk ESTs were assembled into contigs with any identified fmESTs by clustering alignment. Based on these findings, we have concluded that our fmEST algorithm, involving the functional motif discovery procedure, is a valuable approach, enabling us to break new ground in undeveloped invertebrate EST analysis. This work was presented in part at the 11th International Symposium on Artificial Life and Robotics, Oita, Japan, January 23–25, 2006     

Prediction of the mechanical properties of lumber by stress-wave velocity and Pilodyn penetration of 36-year-old Japanese larch trees

The objective of this study was to obtain basic knowledge for the prediction of the mechanical properties of Japanese larch lumber (Larix kaempferi) on the basis of tree properties, such as the stress-wave velocity (SWV) and Pilodyn penetration value (Py). The values of the correlation coefficient between the SWV of a standing tree and the dynamic Young’s modulus (DMOE) of logs, which were obtained at various heights, gradually decreased with an increase in the log sampling height, indicating that the SWV of a tree is affected by wood properties at the measuring position. A significant correlation between the SWV of trees and the average modulus of elasticity (MOE) of lumber was found (r =0.834). A significant negative correlation between the Py of a tree and the average modulus of rupture (MOR) of lumber was also found (r=-0.859). A high coefficient of determination for an obtained regression curve was found when both the SWV and Py of a tree were used for evaluating the average MOE or MOR of lumber. These results indicate that the average MOE and MOR of lumber can be predicted by using the SWV and Py of the Japanese larch tree.     

Metals by Micro‐Scale Additive Manufacturing: Comparison of Microstructure and Mechanical Properties

Many emerging applications in microscale engineering rely on the fabrication of 3D architectures in inorganic materials. Small‐scale additive manufacturing (AM) aspires to provide flexible and facile access to these geometries. Yet, the synthesis of device‐grade inorganic materials is still a key challenge toward the implementation of AM in microfabrication. Here, a comprehensive overview of the microstructural and mechanical properties of metals fabricated by most state‐of‐the‐art AM methods that offer a spatial resolution ≤10 μm is presented. Standardized sets of samples are studied by cross‐sectional electron microscopy, nanoindentation, and microcompression. It is shown that current microscale AM techniques synthesize metals with a wide range of microstructures and elastic and plastic properties, including materials of dense and crystalline microstructure with excellent mechanical properties that compare well to those of thin‐film nanocrystalline materials. The large variation in materials' performance can be related to the individual microstructure, which in turn is coupled to the various physico‐chemical principles exploited by the different printing methods. The study provides practical guidelines for users of small‐scale additive methods and establishes a baseline for the future optimization of the properties of printed metallic objects—a significant step toward the potential establishment of AM techniques in microfabrication.     

The scarab beetleAnomala albopilosa sakishimana utilizes the same sex pheromone blend as a closely related and geographically isolated species,Anomala cuprea

Two components were identified in the sex pheromone system of the green chafter,Anomala albopilosa sakishimana Nomura: (R,Z)-5-(–)-(oct-1-enyl)oxacyclopentan-2-one (buibuilactone) and (R,Z)-5-(–)-(dec-1-enyl)oxyacyclopentan-2-one (japonilure), which have been previously identified as sex pheromone constituents ofA. cuprea andA. octiescostata. A female-specific minor component, (R,E)-5-(–)-(oct-1-enyl)oxacyclopentan-2-one, did not seem to be involved in pheromonal communication because it was not EAD active, but its role remained unclear. A synthetic blend of the two components captured significantly more beetles than any other treatments. Nevertheless, the fact that both the synthetic sex pheromone and field-captured female beetles were weak lures convinced us that the sex pheromone system may be only part of a complex communication system, probably involving plant volatiles. Although the sex pheromone was released during both the scotophase and photophase, there was an increase of 60% in the photophase.     

Independent self-assembly of cadmium-binding {alpha}-fragment of metallothionein in Escherichia coli without participation of {beta}-fragment

We examined the independent self-assembly of the - and ß-fragmentsof human metallothionein (MT) into cadmiumbinding conformationin an Escherichia coli expression system, in addition to wild-typeMT expression. The expressed -fragment formed independentlythe structure of a metal-binding cluster without the aid ofthe ß-fragment. The -fragment and wild-type MT expressedin E.coli were purified and analyzed for their biochemical andspectroscopic properties. The apparent cadmium binding of the-fragment was approximately 12-fold greater than that for thewild-type MT, whereas in other respects the studied biochemicalproperties were similar. In contrast, we were unable to obtainany independently expressed ß-fragment as the cadmium-bindingform in this study. Possible explanations for this phenomenonare discussed.