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Most gnathostomata craniofacial structures derive from pharyngeal arches (PAs), which are colonized by cranial neural crest cells (CNCCs). The anteroposterior and dorsoventral identities of CNCCs are defined by the combinatorial expression of Hox and Dlx genes. The mechanisms associating characteristic Hox/Dlx expression patterns with the topology and morphology of PAs derivatives are only partially known; a better knowledge of these processes might lead to new concepts on the origin of taxon-specific craniofacial morphologies and of certain craniofacial malformations. Here we show that ectopic expression of Hoxa2 in Hox-negative CNCCs results in distinct phenotypes in different CNCC subpopulations. Namely, while ectopic Hoxa2 expression is sufficient for the morphological and molecular transformation of the first PA (PA1) CNCC derivatives into the second PA (PA2)-like structures, this same genetic alteration does not provoke the transformation of derivatives of other CNCC subpopulations, but severely impairs their development. Ectopic Hoxa2 expression results in the transformation of the proximal Meckel's cartilage and of the malleus, two ventral PA1 CNCCs derivatives, into a supernumerary styloid process (SP), a PA2-derived mammalian-specific skeletal structure. These results, together with experiments to inactivate and ectopically activate the Edn1-Dlx5/6 pathway, indicate a dorsoventral PA2 (hyomandibular/ceratohyal) boundary passing through the middle of the SP. The present findings suggest context-dependent function of Hoxa2 in CNCC regional specification and morphogenesis, and provide novel insights into the evolution of taxa-specific patterning of PA-derived structures.

As the size of Resource Description Framework (RDF) graphs has grown rapidly, SPARQL query processing on the large-scale RDF graph has become a more challenging problem. For efficient SPARQL query processing, the handling of the intermediate results is the most crucial element because it generally involves many join operators. Recently, a triple filtering method, called the RP-filter, which uses a path-based index, was proposed. It can reduce the intermediate results effectively by filtering out irrelevant triples in advance. However, its filtering power is limited, because it uses only the path information of the RDF graph. In this paper, we extend the triple filtering method to exploit the graph-structural information, and propose the RDF graph index (RG-index). We address the problem of the RG-index, which is caused by the indexing of the graph patterns, by indexing only effective graph patterns for the triple filtering. In addition, we propose an efficient method for building the RG-index in which a frequent graph pattern mining algorithm is adapted. We conducted comprehensive experiments on large-scale RDF datasets and demonstrated that the RG-index can reduce redundant intermediate results more effectively than can the RP-filter.

Endothelin-1 (Edn1), originally identified as a vasoconstrictor peptide, is involved in the development of cranial/cardiac neural crest-derived tissues and organs. In craniofacial development, Edn1 binds to Endothelin type-A receptor (Ednra) to induce homeobox genes Dlx5/Dlx6 and determines the mandibular identity in the first pharyngeal arch. However, it remains unsolved whether this pathway is also critical for pharyngeal arch artery development to form thoracic arteries. Here, we show that the Edn1/Ednra signaling is involved in pharyngeal artery development by controlling the fate of neural crest cells through a Dlx5/Dlx6-independent mechanism. Edn1 and Ednra knock-out mice demonstrate abnormalities in pharyngeal arch artery patterning, which include persistent first and second pharyngeal arteries, resulting in additional branches from common carotid arteries. Neural crest cell labeling with Wnt1-Cre transgene and immunostaining for smooth muscle cell markers revealed that neural crest cells abnormally differentiate into smooth muscle cells at the first and second pharyngeal arteries of Ednra knock-out embryos. By contrast, Dlx5/Dlx6 knockout little affect the development of pharyngeal arch arteries and coronary arteries, the latter of which is also contributed by neural crest cells through an Edn-dependent mechanism. These findings indicate that the Edn1/Ednra signaling regulates neural crest differentiation to ensure the proper patterning of pharyngeal arch arteries, which is independent of the regional identification of the pharyngeal arches along the dorsoventral axis mediated by Dlx5/Dlx6.

Accelerated soil erosion is a worldwide problem because of its economic and environmental impacts. To effectively estimate soil erosion and to establish soil erosion management plans, many computer models have been developed and used. The Revised Universal Soil Loss Equation (RUSLE) has been used in many countries, and input parameter data for RUSLE have been well established over the years. However, RUSLE cannot be used to estimate the sediment yield for a watershed. Thus, the GIS-based Sediment Assessment Tool for Effective Erosion Control (SATEEC) was developed to estimate soil loss and sediment yield for any location within a watershed using RUSLE and a spatially distributed sediment delivery ratio. SATEEC was enhanced in this study by developing new modules to: 1) simulate the effects of sediment retention basins on the receiving water bodies, 2) estimate the sediment yield from a single storm event, and 3) prepare input parameters for the Web-based sediment decision support system using a GIS interface. The enhanced SATEEC system was applied to the study watershed to demonstrate how the enhanced system can be effectively used for soil erosion control. All the procedures are fully automated with Avenue, CGI, and database programming; thus the enhanced SATEEC system does not require experienced GIS users to operate the system. This easy-to-operate SATEEC system can be used to identify areas vulnerable to soil loss and to develop efficient soil erosion management plans.

A detailed study to achieve optically efficient GaInNAs QWs by low-pressure metal-organic chemical vapor deposition (LP-MOCVD) is reported. It was found that the insertion of GaNAs/InGaAs layers to GaInNAs QW/GaAs barrier is very effective to control the emission wavelength and improve the optical property of QW. Indium rich (as high as 40%) GaInNAs QWs grown at higher V/III ratio are more desirable to extend emission wavelength over 1.3 μm due to reduced incorporation of impurities. The optical efficiencies of the QW structure were confirmed by the lasing performance in edge-emitting laser. The threshold current density and slope efficiency per facet of a 1360 nm laser diode are measured to be 892 A/cm2 and 0.135 W/A, respectively.

A comprehensive study to achieve optically efficient GaInNAs quantum wells (QWs) grown by low-pressure metalorganic vapor phase epitaxy (MOVPE) has been accomplished. In order to extend emission wavelength over 1.3 μm effectively, GaInNAs QW structures with multiple barriers of GaNAs/InGaAs were proposed. Significant improvement of photoluminescence efficiencies and easy controllability of emission wavelengths over the 1.3 μm range were demonstrated with the proposed structure. It is believed that the wavelengths emitted from our employed QW structures are correlated to the amount of strain, determined by the strain competition between InGaAs (compressive) and GaNAs (tensile) layers. As N contents increased in the QWs, the emission wavelength was able to extend up to 1.38 μm without deteriorating spectral width.

GaN epilayers were grown on sapphire and were nitridated for various time lengths at different temperatures (0–60 min, 750–850°C) using the N 2 helicon wave plasma assisted evaporation deposition process. The relationship between the structure of the nitridated layers and the epitaxial growth of GaN was investigated performing a synchrotron X-ray analysis. It was found that when the nitridated layer had the highest quality crystallinity, the GaN overlayer grown on the nitridated layer showed greatly improved crystalline and luminescent properties. Although the amount of compressive strain in the optimally nitridated layer was about 1%, this layer showed low in-plane mosaicity and the largest domain size. However, excessive nitridation causes strain relaxation by reduction of the lateral domain size and the increase of lateral mosaicity, resulting in the degradation of GaN overlayers. Therefore, the adequately nitridated layer with compressive strain is a better provider of nuclei of subsequent nitride overlayers than the fully relaxed layer.

The low-temperature growth of GaN on (0 0 0 1) sapphire substrates was studied using excited neutral nitrogen molecules as an approach to avoid ion damage in the ion beam assisted evaporation process. The excited neutral nitrogen molecules (N 2 ∗ ), together with nitrogen ions (N 2 + ), were produced by electron impact in the discharge chamber encased in the ion source. To selectively extract N 2 ∗ , the single grid configuration was replaced by a grounded triple grid configuration, through which the flux of ionic species to the growing film surface was significantly reduced. The crystallinity and luminescent properties of GaN films were greatly improved due to the increasing ratio flux of excited neutral/ion in the triple-grid configuration. TEM results inferred that the bombardment of ion beam on the growing GaN surface can induce a significant residual stress and more defects, compared to the excited neutral beam. The effect of the non-ionic nitrogen species on the film crystallinity is discussed in the aspect of kinetic energy. As the discharge voltage of the ion source increased, more energetic neutrals were generated by the charge transfer collision between nitrogen ions and thermal neutrals, and degraded the properties of GaN film.

A high density helicon wave plasma was used to synthesize a thin film of cubic boron nitride (c-BN) on the Si(100) substrate. Borazine (B 3 N 3 H 6 ) vapor was directly introduced into the reaction chamber where the plasma density was greater than 10 10 –10 11 cm −3 . The plasma density high enough to dissociate borazine effectively resulted in depositing a relatively good stoichiometric BN film without additional nitrogen sources. The bombardment of energetic ions with a high flux and energy is necessary for the growth of c-BN. The BN film synthesized at the condition of plasma density and rf substrate bias of 8.5 × 10 10 cm −3 and −350 V, respectively, was confirmed to be of cubic phase by both the FT-IR and TEM analyses. However, there existed an excessive compressive residual stress of 4–8 GPa in the c-BN film, which resulted in poor adhesion. The adhesion of c-BN film was significantly improved without a phase transformation through the post-heat treatment at 800 °C in N 2 atmosphere to relax the compressive residual stress.

The dissociation kinetics of CeIII and GdIII complexes of macrocyclic DTPA bis(amide) have been studied in aqueous solution using CuII ions as the scavenger. The measurements were made at 25°C in a solution of 0.100 M (NaClO4) ionic strength. The rates of dissociation of these complexes have been found to be independent of [acetate]. Dissociation of the complexes takes place via both dissociative and associative pathways. The rates of both processes decrease in the order Gd(DTPA)-EAM > Gd(DTPA)-PAM ⋍ Gd(DTPA)-XAM > Gd(DTPA)-BAM > Gd(DTPA)-PenAM. An increase in ring size of the DTPA bis(amide) ligands leads to an increase in kinetic inertness, reflecting the enhanced participation of the amide carbonyl oxygen in lanthanide(III) ion coordination. The substitution of an aromatic ring between the two amide nitrogens, however, results in a significant decrease in kinetic inertness of the resulting DTPA-XAM complex.

BACKGROUND/AIM Nucleotide binding oligomerization domain (Nod) proteins are members of a family that includes the apoptosis regulator APAF1. Nod proteins have been implicated in the induction of NF-κB activity and in the activation of caspases. Helicobacter pylori (H. pylori) infection is reported to express TLR 4, TLR-5 and TLR-9 in gastric epithelial cells. However, TLR-4 and TLR-5 are not recognized as important role in H. pylori infection. This implicated that another signal transducer different from TLR pathway may affect NFκB activation in cag PAI (+) H. pylori infection. The purpose of this study was to investigate whether cag PAI (+) H. pylori infection affects NF-κB activation and IL-8 production through Nod1 and to evaluate the transepithelial neutrophil migration induced by H. pylori infection. METHODS Stable transfection of Dominant Negative (DN) Nod1 in AGS cell line was established followed by NF-κB activation and IL-8 production by H. pylori HP 99 infection was assessed. The role of cag PAI was examined comparing wild type H. pylori strain with cag PAI knock-down CagAand CagEH. pylori strain. To assess the production of IL-8, we examined mRNA expression using RT-PCR, and IL-8 secretion using ELISA. To assess the inhibition of NF-κB activation, we examined degradation and phosphorylation of IκBα using western blot and EMSA. To examine the role of cag PAI, we examined the production of IL-8 and the inhibition of NF-κB activation in the cag PAI knock-down CagAand CagEH. pylori infection in the same manner with wild type. We established the neutrophil migration model induced by H. pylori infection in polarized DN Nod1 Caco-2 cell line and evaluated transepithelial neutrophil migration as to the cag PAI status. RESULTS Stable transfection of DN Nod1 followed by cag PAI (+) H. pylori inhibited IL-8 mRNA expression and IL-8 production. In addition, cag PAI (+) H. pylori inhibited IκB-α degradation and IκB-α phosphorylation. IL-8 mRNA expression and IL-8 production by CagA-and CagEH. pylori were significantly decreased compared with those by wild type H. pylori. IκB-α degradation and IκB-α phosphorylation by CagA-and CagEH. pylori were significantly decreased compared with those by wild type H. pylori. NF-κB expression by CagA-and CagEH. pylori was significantly decreased compared with that by wild type H. pylori. Transepithelial neutrophil migration was more prominent in wild type H. pylori than CagAand CagEH. pylori CONCLUSION Signaling through Nod1 plays an essential role in the upregulated expression of IL-8 in human epithelial cells infected with H. pylori.