Self-poling effect on Mn-doped Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals synthesized by solid-state single crystal growth method

Department of Materials Science and EngineeringPiezoelectric single crystal such as PZN-PT [Pb(Zn1/3Nb2/3)O3-PbTiO3] and PMN-PT [Pb(Mg1/3-Nb2/3)O3-PbTiO3] which have magnificent piezoelectric properties, have been used for various applications, e.g., sensors, transducers and actuators. For piezoelectric applications, ferroelectric materials are usually employed because of their high performance after poling process. Poling process that forces ferroelectric domains to alignotherwise, randomly oriented, is essential in making a ferroelectric into a piezoelectric. It is typically performed at an elevated temperature by applying a certain amount of a unipolar electric field for some time since domain alignment is a time-dependent thermally activated process. However, induced piezoelectric properties generally disappear when ferroelectric material is heated up to Curie temperature (Tc) where aligned dipoles scatter. Because the synthesis of common ferroelectric materials is processed at high temperature, ferroelectric materials must be poled for piezoelectric application. In this paper, ferroelectric PMN-PT single crystals with doping Mn for inducing self-poling effect will be discussed. The Mn-doped PMN-PT exhibits a high piezoelectric response without any poling process. Moreover, high piezoelectric properties are re-induced after heating above TC with self-poling on cooling process. The defect-dipoles which is caused by Mn ions generate internal bias fields (Ei) which give forces aligning dipoles of PMN-PT to have spontaneous polarization. The Mn-PMN-PT crystal which is able to be self-poled has its own preferred poling direction. So opposite DC-poling can enhance piezoelectric and dielectric performances like AC-poling which is highly interested by ferroelectric single crystal society. The mechanism presented in this paper can offers a new perspective for enhancing the dielectric and piezoelectric properties of doped ferroelectric single crystals.clos

Suppression of Dielectric Loss at High Temperature in (Bi1/2Na1/2)TiO3 Ceramic by Controlling A-site Cation Deficiency and Heat Treatment

Dielectric capacitors are integral components in electronic devices that protect the electric circuit by providing modulated steady voltage. Explosive growth of the electric automobile market has resulted in an increasing demand for dielectric capacitors that can operate at temperatures as high as 400oC. To surpass the operation temperature limit of currently available commercial capacitors that operate in temperatures up to 125oC, Bi1/2Na1/2TiO3 (BNT), which has a large temperature-insensitive dielectric response with a maximum dielectric permittivity temperature of 300oC, was selected. By introducing an intentional A-site cation deficiency and post-heat treatment, we successfully manage to control the dielectric properties of BNT to use it for high-temperature applications. The key feature of this new BNT is remarkable reduction in dielectric loss (0.36 to 0.018) at high temperature (300oC). Structural, dielectric, and electrical properties of this newly developed BNT were systematically investigated to understand the underlying mechanism

Effect of Internal Bias Field on Poling Behavior in Mn-Doped Pb(Mg1/3Nb2/3)O3-29 mol%PbTiO3 Single Crystal

Electrical poling is a crucial step to convert ferroelectrics to piezoelectrics. Nevertheless, no systematic investigation on the effect of poling has been reported. Given that the poling involves an alignment of spontaneous polarization,the condition for poling should be different when a material has an internal bias field that influences the domain stability. Here, we present the effect of poling profile on the dielectric and piezoelectric properties in Mn-doped Pb(Mg1/3Nb2/3)O3-29 mol%PbTiO3 single crystal with an internal bias field. We showed that both the dielectric permittivity and the piezoelectric coefficient were further enhanced when the poling procedure ends with a field application along the opposite direction to the internal bias field. We expect that the current finding would give a clue to understanding the true mechanism for the electrical poling

3-dimensional Modeling and Mining Analysis for Open-pit Limestone Mine Stope Using a Rotary-wing Unmanned Aerial Vehicle

The purpose of this study is to show the possibility of 3-dimensional modeling of open-pit limestone mine by using a rotary-wing unmanned aerial vehicle, a drone, and to estimate the amount of mining before and after mining of limestone by explosive blasting. Analysis of the image duplication of the mine has shown that it is possible to achieve high image quality. Analysis of each axis error at the shooting position after analyzing the distortions through camera calibration was shown the allowable range. As a result of estimating the amount of mining before and after explosive blasting, it was possible to estimate the amount of mining of a wide range quickly and accurately in a relatively short time. In conclusion, it is considered that the drone of a rotary-wing unmanned aerial vehicle can be usefully used for the monitoring of open-pit limestone mines and the estimation of the amount of mining. Furthermore, it is expected that this method will be utilized for periodic monitoring of construction sites and road slopes as well as open-pit mines in the future

Insecticidal activities of a Diospyros kaki root-isolated constituent and its derivatives against Nilaparvata lugens and Laodelphax striatellus

a b s t r a c t a r t i c l e i n f o Diospyros kaki root-derived materials were examined for insecticidal properties against Nilaparvata lugens and Laodelphax striatellus. Based on the LD 50 values, the chloroform fraction of D. kaki extracts showed the most activity against N. lugens (3.78 μg/female) and L. striatellus (7.32 μg/female). The active constituent of the chloroform fraction was isolated by various chromatographic methods and was identified as 5-hydroxy-2-methyl-1,4-naphthoquinone by spectroscopic analyses. To establish the structure-activity relationships, the insecticidal effects of 5-hydroxy-2-methyl-1,4-naphthoquinone and its derivatives against N. lugens and L. striatellus were determined using micro-topical application bioassays. On the basis of LD 50 values, 5-hydroxy-1,4-naphthoquinone was the most effective against N. lugens (0.072 μg/female) and L. striatellus (0.183 μg/ female). 2-Bromo-1,4-naphthoquinone, 2-hydroxy-1,4-naphthoquinone, and 5-hydroxy-2-methyl-1,4-naphthoquinone also had potent insecticidal activities against N. lugens and L. striatellus. In contrast, no insecticidal activity was observed with 2-methoxy-1,4-naphthoquinone or 2-methyl-1,4-naphthoquinone. These results indicate that the functional group (bromo-and hydroxyl-) at the C-2 position of the 1,4-naphthoquinone skeleton and the change in position of the hydroxyl group play important roles in insecticidal activity. Therefore, naturally occurring D. kaki root-derived 5-hydroxy-2-methyl-1,4-naphthoquinone and its derivatives may be suitable as insecticides

The expression of growth factor signaling genes in co-culture IVM

The objective of this study was to determine the expression of growth factor signaling genes in human adiposederived stem cells (ASCs), porcine oocytes, and cumulus during in vitro maturation (IVM). The human ASCs (from 2 young and 2 old donors) were used for the co-culture IVM system. The maturation rate was examined based on polar body extrusion. The expression of the growth factor signaling genes from ASCs, oocytes, and cumulus were measured using qPCR. All data were analyzed using ANOVA followed by Tukey’s test. The expression of the h-IGF1 signaling genes from human ASCs cells showed similar values in all groups and the h-FGF2 expressions were higher in the young donors than the old ones. The p-FGF2, p-FGFR2, and p-TGFβ1 expressions in the oocytes as well as p-IGFR in the cumulus that were co-cultured from the young donors showed higher values than the old and control groups. The apoptotic ratio (p-BAX/p-BCL2) from the oocytes and cumulus in both co-culture groups also showed lower levels than the control (P<0.05). Oocyte maturation rates were significantly increased in all co-cultured groups (Y1 (85.9 ± 2.2%), Y2 (91.2 ± 1.1%), O1 (86.3 ± 1.5%), and O2 (86.5 ± 2.3%)) compared with the control (76.7 ± 1.1%; P<0.05). Although the expression of growth factor signaling genes was varied, young donors’ ASCs might support in vitro maturation beħer than those from old donors

Post-mortem re-cloning of a transgenic red fluorescent protein dog

Recently, the world's first transgenic dogs were produced by somatic cell nuclear transfer. However, cellular senescence is a major limiting factor for producing more advanced transgenic dogs. To overcome this obstacle, we rejuvenated transgenic cells using a re-cloning technique. Fibroblasts from post-mortem red fluorescent protein (RFP) dog were reconstructed with in vivo matured oocytes and transferred into 10 surrogate dogs. One puppy was produced and confirmed as a re-cloned dog. Although the puppy was lost during birth, we successfully established a rejuvenated fibroblast cell line from this animal. The cell line was found to stably express RFP and is ready for additional genetic modification

Correction to: Failure to maintain full-term pregnancies in pig carrying klotho monoallelic knockout fetuses

An amendment to this paper has been published and can be accessed via the original article

Genomic profile analysis of diffuse-type gastric cancers

Background: Stomach cancer is the third deadliest among all cancers worldwide. Although incidence of the intestinal-type gastric cancer has decreased, the incidence of diffuse-type is still increasing and its progression is notoriously aggressive. There is insufficient information on genome variations of diffuse-type gastric cancer because its cells are usually mixed with normal cells, and this low cellularity has made it difficult to analyze the genome. Results: We analyze whole genomes and corresponding exomes of diffuse-type gastric cancer, using matched tumor and normal samples from 14 diffuse-type and five intestinal-type gastric cancer patients. Somatic variations found in the diffuse-type gastric cancer are compared to those of the intestinal-type and to previously reported variants. We determine the average exonic somatic mutation rate of the two types. We find associated candidate driver genes, and identify seven novel somatic mutations in CDH1, which is a well-known gastric cancer-associated gene. Three-dimensional structure analysis of the mutated E-cadherin protein suggests that these new somatic mutations could cause significant functional perturbations of critical calcium-binding sites in the EC1-2 junction. Chromosomal instability analysis shows that the MDM2 gene is amplified. After thorough structural analysis, a novel fusion gene TSC2-RNF216 is identified, which may simultaneously disrupt tumor-suppressive pathways and activate tumorigenesis. Conclusions: We report the genomic profile of diffuse-type gastric cancers including new somatic variations, a novel fusion gene, and amplification and deletion of certain chromosomal regions that contain oncogenes and tumor suppressors.open121

Pathogenesis of Korean SapelovirusA in piglets and chicks.

Sapelovirus A (SV-A), formerly known as porcine sapelovirus as a member of a new genus Sapelovirus, is known to cause enteritis, pneumonia, polioencephalomyelitis and reproductive disorders in pigs. We have recently identified α2,3-linked sialic acid on GD1a ganglioside as a functional SV-A receptor rich in the cells of pigs and chickens. However, the role of GD1a in viral pathogenesis remains elusive. Here, we demonstrated that a Korean SV-A strain could induce diarrhoea and intestinal pathology in piglets but not in chicks. Moreover, this Korean SV-A strain had mild extra-intestinal tropisms appearing as mild, non-suppurative myelitis, encephalitis and pneumonia in piglets, but not in chicks. By real-time reverse transcription (RT) PCR, higher viral RNA levels were detected in faecal samples than in sera or extra-intestinal organs from virus-inoculated piglets. Immunohistochemistry confirmed that high viral antigens were detected in the epithelial cells of intestines from virus-inoculated piglets but not from chicks. This Korean SV-A strain could bind the cultured cell lines originated from various species, but replication occurred only in cells of porcine origin. These data indicated that this Korean SV-A strain could replicate and induce pathology in piglets but not in chicks, suggesting that additional porcine-specific factors are required for virus entry and replication. In addition, this Korean SV-A strain is enteropathogenic, but could spread to the bloodstream from the gut and disseminate to extra-intestinal organs and tissues. These results will contribute to our understanding of SV-A pathogenesis so that efficient anti-sapelovirus drugs and vaccines could be developed in the future.This study was supported by a grant (2014R1A2A2A01004292) of the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning, Bio-industry Technology Development Program (315021-04) through the Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries (iPET) funded by the Ministry of Agriculture, Food and Rural Affairs, and Korea Basic Science Institute grant (C33730), Republic of Korea. IG is a Wellcome Senior Fellow supported by the Wellcome Trust (097997/Z/11/Z). Chonnam National University provided funding to Mun-Il Kang (2012). The Mab against SV-A capsid protein was received as a generous gift from Dr. M. Dauber (Friedrich-Loeffler Institute, Germany).This is the accepted version of the article. The final version is available from the Microbiology Society via http://dx.doi.org/10.1099/jgv.0.00057