Giant Spin-Valve Effect in Planar Spin Devices Using an Artificially Implemented Nanolength Mott-Insulator Region.

Developing technology to realize oxide-based nanoscale planar integrated circuits is in high demand for next-generation multifunctional electronics. Oxide circuits can have a variety of unique functions, including ferromagnetism, ferroelectricity, multiferroicity, superconductivity, and mechanical flexibility. In particular, for spin-transistor applications, the wide tunability of the physical properties due to the presence of multiple oxide phases is valuable for precise conductivity matching between the channel and ferromagnetic electrodes. This feature is essential for realistic spin-transistor operations. Here, a substantially large magnetoresistance (MR) ratio of up to ≈140% is demonstrated for planar-type (La,Sr)MnO3 (LSMO)-based spin-valve devices. This MR ratio is 10-100 times larger than the best values obtained for semiconductor-based planar devices, which have been studied over the past three decades. This structure is prepared by implementing an artificial nanolength Mott-insulator barrier region using the phase transition of metallic LSMO. The barrier height of the Mott-insulator region is only 55 meV, which enables the large MR ratio. Furthermore, a successful current modulation, which is a fundamental functionality for spin transistors, is shown. These results open up a new avenue for realizing oxide planar circuits with unique functionalities that conventional semiconductors cannot achieve.

Pulpal response to a newly developed MMA based resin cement for bonding tooth-colored indirect restorations.

PURPOSE: To evaluate the pulpal responses to a newly-developed MMA-based self-etch resin cement, when used as a luting agent for indirect resin composite restoration, and to compare the results with those obtained from a total-etch luting agent, glass-ionomer cement, and amalgam restoration. METHODS: 120 cervical cavities were prepared in monkey teeth and divided into four equal groups according to the restorative materials used: (1) the cavities were restored with resin composite inlays using a self-etch resin cement as a luting agent (M-Bond); (2) the cavities were also restored with resin composite inlays but using a total-etch resin cement as a luting agent (Super-Bond C & B); (3) the cavities were directly restored with glass-ionomer cement (Fuji II); or (4) the cavities were directly restored with amalgam (Dispersalloy). The restored teeth were extracted at 3, 30, or 90 days after restoration, then fixed in 10% neutral buffered formalin. The specimens were prepared using routine histopathological procedures. Five microm-thick sections were stained with hematoxylin and eosin or Brown & Brenn gram stain for bacterial observations. Histological responses in the pulpal tissue and bacterial penetration were observed under a light microscope and evaluated using standard scores. The results were statistically analyzed using the Kruskal-Wallis test (P< 0.05). RESULTS: At all time intervals, no significant differences of pulpal inflammatory responses between M-Bond and Super-Bond C&B were observed (P> 0.05). Both resin cements showed no serious pulpal responses, such as necrosis or abscess formation. In general, both MMA-based resin cements showed similar pulpal responses to those of glass-ionomer cement except for congestion of pulpal blood vessels at 3 days after restoration in which glass-ionomer cement exhibited a lower level than that of the MMA-based resin cements. For the group restored with amalgam, at 3 days after restoration, severe odontoblastic disorders and blood vessel congestions with a large infiltration of inflammatory cells were detected. At 30 and 90 days after restoration, slightly inflammatory irritations were observed irrespective of the materials used. Reparative dentin formation and bacterial penetration were found mostly in the group restored with amalgam.

Gene structure and biochemical characterization of mitochondrial single-stranded DNA binding protein from Schizosaccharomyces pombe.

We studied the genomic structure and biochemical properties of Schizosaccharomyces pombe mitochondrial single-stranded DNA binding protein (mtSSB). We first determined the full-length cDNA sequence of mtSSB and clarified the exon/intron structure of the mtSSB gene (rim1), including the transcription initiation and polyadenylation sites. The cDNA of rim1 gene encoded 150 amino acids and the sequence showed homology to eukaryotic mtSSB and Escherichia coli SSB. We overexpressed mtSSB as a His-tag fusion protein in E. coli and obtained an anti-mtSSB antibody. Gel filtration analysis of S. pombe cell extracts clarified that mtSSB has a tetrameric structure. We also immunochemically detected mtSSB in S. pombe cell extract and showed that 15,000 molecules of mtSSB tetramer are present in a single S. pombe cell. Mature mtSSB lacking the presequence was overexpressed in E. coli in tetrameric soluble form. The recombinant mtSSB bound a single-stranded oligonucleotide and phiX174 virion DNA with almost identical binding activity as E. coli SSB.

Effect of a fluoride-releasing one-step adhesive system on monkey pulp tissue.

PURPOSE: The purpose of this study was to evaluate the pulpal response of a fluoride-releasing one-step adhesive in nonexposed monkey teeth. MATERIALS AND METHODS: Cervical Class V cavities were prepared in monkey teeth. The cavities were divided into three groups of different restorative materials. A one-step adhesive (SI-IB551, Shofu) was applied to the teeth, and the cavities were filled with a resin composite (Beautifil, Shofu). In the other two groups, a two-step adhesive (Imperva FluoroBond, Shofu) together with either a resin composite (Beautifil) or a glass-ionomer cement (Fuji II, GC) was placed in the cavities. The teeth were then extracted after 3, 30, and 90 days, fixed in 10% buffered formalin solution, and prepared according to routine histological techniques. Five-micrometer sections were stained with hematoxylin and eosin, or Brown & Brenn gram stain for bacterial observation. Four histological features, odontoblastic change, inflammatory cell infiltrate, reparative dentin formation, and the bacterial staining, were evaluated and compared. The results were compared statistically with significance defined as p < 0.05 (Kruskall-Wallis test). RESULTS: Disarrangement of the odontoblasts and slight inflammatory cell infiltrations were the main initial reactions, while deposition of reparative dentin was the major long-term reaction in all groups. No statistically significant differences in the four histological features were seen among the restorative materials placed in the cavities (p > 0.05). No serious pulpal inflammatory reactions, such as necrosis or abscess formation, were observed in any of the experimental groups. CONCLUSION: The one-step adhesive showed acceptable biological compatibility with the monkey pulp, whereas the pulpal response to the system was minimally different from that of the glass-ionomer cement or the two-step self-etching adhesive.

Monkey pulpal response to an MMA-based resin cement as adhesive luting for indirect restorations.

PURPOSE: The objective of this study was to evaluate the pulpal response to a newly-developed MMA resin cement (MultiBond, Tokuyama) when used for adhesively luting composite resin inlays. MATERIALS AND METHODS: Cervical cavities were prepared in monkey teeth. The teeth were randomly divided into 3 groups. In the experimental group, a self-etching primer and a resin cement were applied to the cavities, and then hybrid composite inlays (Estenia, Kuraray) were inserted using freshly mixed resin cement. In the other groups, a zinc oxide/eugenol cement (Eugedain, Showa Yakuhin Kakou) or a glass-ionomer cement (Fuji II, GC) was used to fill the cavity. The teeth were then extracted after 3, 30, and 90 days, fixed in 10% buffered formalin solution, and prepared using routine histological techniques. Five-mum-thick sections were stained with hematoxylin and eosin, or Brown & Brenn gram stain for bacterial observation. Histopathological reactions in the pulp tissue and bacterial penetration along the cavity walls were assessed using a standardized score. RESULTS: No serious inflammatory reactions in the pulp, such as necrosis or abscess formation, were observed in any of the experimental periods, except for 1 case after 30 days, in which a pulpal exposure was suspected. Disarrangement of the odontoblast layer and deposition of reparative dentin were the major reactions observed in this specimen. No bacterial penetration along the cavity walls was detected. The monkey pulpal response and in vivo sealing ability of the MMA resin cement in combination with the self-etching primer was considered as good as that of the glass-ionomer cement. CONCLUSION: The new MMA resin cement showed acceptable biological compatibility to the monkey pulp when used to adhesively lute composite resin inlays.

Pulpal response to a hybrid composite resin inlay bonded with a newly developed resin-modified glass ionomer luting cement.

This study evaluated the pulpal response of hybrid composite resin inlay luted with a resin-modified glass ionomer cement, and compared it with a glass ionomer cement and an amalgam. Cervical cavities were prepared in monkey teeth. A resin-modified glass ionomer luting cement (Ionotite F, Tokuyama Dental Corp.) was applied to the teeth in one of the experimental groups, and then hybrid composite resin inlays (Estenia, Kuraray Medical Inc.) were bonded to the cavities. The teeth were extracted after 3, 30, and 90 days and stained with Hematoxylin and Eosin staining or Brown and Brenn gram stain for bacterial observation. No serious inflammatory reaction of the pulp, such as necrosis or abscess formation, was observed in any of the experimental groups. No bacterial penetration along the cavity walls was detected in the resin-modified glass ionomer luting cement group. Hence, the resin-modified glass ionomer luting cement showed an acceptable biological compatibility with monkey pulp.

Structure and transcription promoter activity of mouse flap endonuclease 1 gene: alternative splicing and bidirectional promoter.

Flap endonuclease 1 (FEN1) is a structure-specific nuclease involved in DNA replication and repair. The mouse Fen1 gene, which has two exons, is located immediately adjacent to the gene corresponding to full-length cDNA of Riken 1810006K21 (1810006K21Rik) in a head-to-head orientation. Transcription initiation sites of each gene are 274 bp apart in the mouse genome. The spacer sequence between the bidirectional genes contains a CpG island, but lacks the typical TATA box. In the present study, transcription of the mFen1 gene was started from two initiation sites, and the first noncoding exon was spliced to the second exon using two different splicing donor sites, producing 3 kinds of mFen1 transcripts. A 594-bp fragment between the mFen1 and 1810006K21Rik genes, which contains two conserved sequence blocks (CSB) between mouse and human sequence, functions as a bidirectional promoter. The multiple cis-elements, including an Ets-binding site and E-box in the CSB, are involved in activation or repression of transcription in both directions. Interestingly, the E-box activates mFen1 transcription and simultaneously represses promoter activity in the opposite direction. Mutation of either splicing donor site of the mFen1 gene produced limiting alternative splicing products, but did not affect luciferase activity. In contrast, the splicing-defective mutation produced by disruption of the acceptor site completely lacked luciferase activity, indicating that the splicing has a significant effect on production of luciferase protein by shortening the 5'-untranslated region of the mRNA.

Effects of a distal protection device during primary stenting in patients with acute anterior myocardial infarction.

BACKGROUND: The angiographic no-reflow phenomenon is an adverse prognostic factor in patients with acute myocardial infarction (AMI). The aim of the present study was to evaluate the effects of an occlusive balloon type distal protection device (PercuSurge GuardWire: GW) during primary stenting in patients with anterior AMI. METHODS AND RESULTS: The GW group included 42 patients treated by primary stenting with GW protection and the control group included 30 patients treated by primary stenting after thrombectomy without distal protection. Left ventricular (LV) function was measured and compared by left ventriculography obtained soon after percutaneous coronary intervention (PCI) and 3 weeks after onset. The corrected TIMI frame count values were lower in the GW group than in the control group (27.5+/-2.3 vs 35.1 +/-2.5, p=0.030). The number of patients with myocardial blush grade 3 after PCI was higher in the GW group than in the control group (45.7 vs 20.0%, p=0.029). Peak concentration of creatine kinase myocardial fraction was lower in the GW group than in the control group (326.6+/-41.5 vs 454.9+/-46.2 mg/dl, p=0.043). GW patients showed greater improvement at 3 weeks after PCI in terms of LV ejection fraction (+4.6+/-1.2 vs -1.1+/-1.5, p=0.004), LV end-systolic volume index (+0.5+/-2.4 vs +9.0+/-2.7, p=0.023), and regional wall motion abnormalities (-2.03+/-0.14 vs -2.51+/-0.14, p=0.018). CONCLUSION: Primary stenting with GW protection can restore epicardial coronary flow and myocardial perfusion, and also preserve LV function in anterior AMI.

Biocompatibility of a flowable composite bonded with a self-etching adhesive compared with a glass lonomer cement and a high copper amalgam.

This study evaluated the pulpal response and in-vivo microleakage of a flowable composite bonded with a self-etching adhesive and compared the results with a glass ionomer cement and amalgam. Cervical cavities were prepared in monkey teeth. The teeth were randomly divided into three groups. A self-etching primer system (Imperva FluoroBond, Shofu) was applied to the teeth in one of the experimental groups, and the cavities were filled with a flowable composite (SI-BF-2001-LF, Shofu). In the other groups, a glass ionomer cement (Fuji II, GC) or amalgam (Dispersalloy, Johnson & Johnson) filled the cavity. The teeth were then extracted after 3, 30 and 90 days, fixed in 10% buffered formalin solution and prepared according to routine histological techniques. Five micrometer sections were stained with hematoxylin and eosin or Brown and Brenn gram stain for bacterial observation. No serious inflammatory reaction of the pulp, such as necrosis or abscess formation, was observed in any of the experimental groups. Slight inflammatory cell infiltration was the main initial reaction, while deposition of reparative dentin was the major long-term reaction in all groups. No bacterial penetration along the cavity walls was detected in the flowable composite or glass ionomer cement except for one case at 30 days in the glass ionomer cement. The flowable composite bonded with self-etching adhesive showed an acceptable biological com- patibility to monkey pulp. The in vivo sealing ability of the flowable composite in combination with the self-etching adhesive was considered comparable to glass ionomer cement. Amalgam restorations without adhesive liners showed slight bacterial penetration along the cavity wall.

Identification of the functional elements in the bidirectional promoter of the mouse O-sialoglycoprotein endopeptidase and APEX nuclease genes.

The gene for mammalian O-sialoglycoprotein endopeptidase (Osgep) lies immediately adjacent to the gene for the APEX nuclease (Apex), a multifunctional DNA repair enzyme, in a head-to-head orientation. To clarify the regulation of these divergent genes, we studied their promoter regions with luciferase reporters. Deletion analysis of a fragment containing the entire mouse Apex gene suggested that cis-acting elements driving in the direction of Osgep are widely distributed in the mApex gene, in the antisense orientation. We investigated in detail cis-acting elements near the transcription initiation site of mOsgep. The spacer sequence between mOsgep and mApex was shown to have bidirectional promoter activity and it has been reported that two CCAAT boxes promote basal transcription in the direction of mApex. However, only one of the CCAAT boxes proximal to the transcription initiation site of mOsgep was important for transcription towards mOsgep. An Sp1-binding sequence was found to be involved in bidirectional transcription and a CRE/ATF-like sequence was shown to function as a repressor of mOsgep transcription. Quantitative RT-PCR showed that the mApex and mOsgep genes were expressed in all tissues examined and that expression of mOsgep was low compared with mApex.

Mitochondrial factors modulate the activity of endonuclease G, the major nuclease of Mammalian mitochondria.

Endonuclease G (Endo G), a sugar-nonspecific nuclease preferring single-stranded DNA (ssDNA), is responsible for major nuclease activity in mitochondria. If the enzyme provides an important nicking function for mitochondrial DNA (mtDNA) in vivo, then mitochondrial factors likely exist which modulate the enzyme's activity and prevent cleavage at single-stranded moieties of mtDNA. In the present paper, we report that specific membrane phospholipids, polyamines and single-stranded DNA-binding protein (SSB) appear to exert such effects in vitro. Phosphatidylcholine and phosphatidylethanolamine, the major constituents of the mitochondrial inner membrane, stimulated purified Endo G activity 5- to 10-fold. Spermine at 5-100 microM also stimulated activity about 4-fold. However, at more than 500 microM, the spermine largely inhibited the degradation of ssDNA and duplex DNA. Escherichia coli SSB, which has physicochemical properties analogous to those of mitochondrial SSB (mtSSB), markedly inhibited the degradation of phiX174 ssDNA by Endo G, indicating the possible involvement of mtSSB in vivo in protection of single-stranded regions of mtDNA from nucleolytic attacks.

Sequencing analysis of a putative human O-sialoglycoprotein endopeptidase gene (OSGEP) and analysis of a bidirectional promoter between the OSGEP and APEX genes.

We performed cDNA and genomic cloning, sequencing and promoter analysis of the putative human O-sialoglycoprotein endopeptidase gene OSGEP (a homologue of gcp, a Pasteurella haemolytica A1 glycoprotease). The cloned OSGEP cDNA is 1311 nucleotides long, and encodes a protein consisting of 335 amino acids with predicted molecular mass of 36.4 kDa. The amino acid sequence of OSGEP showed 29.7% identity with that of P. haemolytica glycoprotease. The OSGEP gene is 7.75 kb long, consists of 11 exons and 10 introns, and lies immediately adjacent to the APEX gene (which encodes APEX nuclease, a multifunctional DNA repair enzyme) in 5'-to-5' orientation. The promoter region of the OSGEP gene lacks the typical TATA box, but has putative regulatory elements in the CpG island. Northern blot analysis showed ubiquitous expression of the OSGEP gene in several tissues, and we observed similarities in expression patterns between OSGEP and APEX. In order to study the regulation of OSGEP gene expression, we analyzed the OSGEP promoter region by luciferase assay using HeLa cells. A functional region required for full transcription activity was narrowed down to a 23 bp region containing a CCAAT box. It has been reported that this CCAAT box promotes basal transcription in the APEX direction. We thus conclude that a bidirectional promoter containing a CCAAT box regulates transcription of both the OSGEP and APEX genes.

Differential intracellular localization of the human and mouse endonuclease III homologs and analysis of the sorting signals.

The mammalian endonuclease III homolog NTH1 is a DNA glycosylase/AP lyase that recognizes oxidized pyrimidine bases. Here, we compared the intracellular localization of human and mouse NTH1 and analyzed their sorting signals by examining expression of enhanced green fluorescent protein (EGFP)-tagged NTH1 protein. Full-length hNTH1 was sorted exclusively into nuclei. Deletion analysis showed that two basic amino acid clusters, which constitute the nuclear localization signal (NLS), are essential for nuclear sorting. Moreover, disruption of the NLS by deletion or substitution of arginine residue(s) altered the localization of the protein to mitochondria. In contrast, most mNTH1 molecules were sorted into mitochondria, with a relatively small amount localized in nuclei. Deletion analysis indicated that the mitochondrial targeting sequence of mNTH1 is contained within the N-terminal 38 amino acids. Alignment of the N-terminal sequence of human and mouse NTH1 showed that mNTH1 lacks a basic amino acid cluster corresponding to one of the NLS sequences found in hNTH1. Nuclear localization of mNTH1 was increased when this NLS sequence was added to mNTH1 through the addition of appropriate amino acids. The fact that transcription of the hNTH1 gene is initiated at multiple sites indicated that three isoforms of hNTH1 protein are translated using different initiation codons. However, no difference in intracellular localization was observed among three isoforms of hNTH1 with different N-terminal sequences.