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A standard cooling rate has not been established for glazing; therefore, the effects of the cooling rate on the properties of zirconia need to be evaluated to predict outcomes in clinical practice. 4Y-TZP glazed at three different cooling rates was analyzed to estimate the effect of cooling rate during glazing on the mechanical and optical properties. Hardness tests, field-emission scanning electron microscopy analysis, X-ray diffraction analysis, flexural strength measurement, and optical property evaluations were performed. When 4Y-TZP was glazed at a higher cooling rate (Cooling-1) than the normal cooling rate (Cooling-2), there was no significant difference in grain size, flexural strength, average transmittance, and translucency parameters. The hardness was slightly reduced. The opalescence parameter was reduced for the 2.03 mm thick specimens. When 4Y-TZP was glazed at a lower cooling rate (Cooling-3) than the normal cooling rate, there was no significant difference in hardness, grain size, flexural strength, and translucency parameters. In addition, the average transmittance and opalescence parameters were slightly reduced for the 0.52 and 2.03 mm specimens, respectively. The effects of the cooling rate during glazing on the mechanical and optical properties of 4Y-TZP appear to be minimal and clinically insignificant. Therefore, even if the cooling rate cannot be strictly controlled during glazing, the clinical outcomes will not be significantly affected.

This paper investigates whether political connection of Chief Executive Officer (CEO) in public institutions is associated with organization efficiency. We utilize two types of public institutions in Korea, state-owned enterprises (SOEs) and quasi-governmental organizations (QUANGOs). Using the Data Envelopment Analysis (DEA), we find that CEOs with political connection are positively related to organization efficiency. Specifically, such association is largely driven by QUANGOs whose revenue resource is fully funded and owned by the government. It implies that politically connected CEOs can improve firm efficiency when the organizations are financially dependent on the government and are under its stringent monitoring by government.

PurposeThis study aims to examine the relationship between the internal control manager attributes and the firms’ operational efficiency. The internal control manager designs and maintains the firms’ policies and procedures to certify the effectiveness of its internal control system.Design/methodology/approachThe study is an empirical research based on a sample of public companies listed on the Korean Stock Exchange from year 2011 to 2015. The authors derive measures of operational efficiency using the data envelopment analysis tool.FindingsThis study shows that the operational efficiency increases with internal control managers’ task-related knowledge and diverse firm knowledge, consistent with human capital theory. Also, the results reveal that internal control managers, equity ownership has a curvilinear relationship with the operational efficiency, indicating that excessive managerial ownership can deteriorate the firm value.Originality/valueWhile many studies have examined the association between the internal control system and financial reporting quality, this paper is differentiated from prior studies by focussing on the internal control managers’ personal attributes. This is important, as the internal control system is essentially built by internal control managers who are in charge. This study contributes to accounting literature by shedding light on the role of internal control managers in enhancing the firms’ operational efficiency.

This study examined the effect of ice-quenching after oxidation treatment with or without vacuum, on the change in the hardness of a Pd-Ag-Au-In metal-ceramic alloy during porcelain-firing simulation. The aim of the present study is to determine whether ice quenching after oxidation renders a Pd-Ag metal-ceramic alloy soft enough for easy processing without the need for an additional solution treatment and whether it affects the final hardness of the Pd-Ag metal-ceramic alloy after porcelain firing simulation. The oxidation treatment resulted in the as-cast specimen becoming homogenized, which was progressed further by vacuuming. The bench-cooling to room temperature after the oxidation resulted in precipitation. From the next firing step, the precipitation occurred during the firing process as well as subsequent bench-cooling; this was owing to the presence of a phase boundary wherein the single phase is separated into two phases between the temperatures of the oxidation treatment (1010 °C) and post-oxidation treatment (~960 °C). During the firing process until main bake, the specimen that was ice-quenched after oxidation maintained a higher hardness than the bench-cooled specimen, particularly for the oxidation treated specimen with vacuum (p 0.05). The mechanism of ice-quenching after oxidation with vacuum to induce further hardening during the firing process involved more active precipitation; this was attributed to the further progress of homogenization during the oxidation. The precipitation reaction in the present study corresponded to the Pd-In binary phase diagram, illustrating that as the firing proceeded, the Pd

This study examined the effect of ice-quenching after oxidation treatment on hardness change of a Pd-Cu-Ga-Zn metal-ceramic alloy during porcelain firing simulation. Although not statistically significant, the alloy was softened slightly during porcelain firing simulation with conventional slow cooling rate. On the other hand, the hardness increased significantly by ice-quenching instead of the slow cooling after oxidation (p0.001). The gap in the final hardness depending on ice-quenching occurred in the matrix and plate-like precipitates but not in the particle-like structure without plate-like precipitates (p0.05). The mechanism of ice-quenching after oxidation to prevent softening and induce hardening during porcelain firing simulation involved the more active precipitation and retardation of microstructural coarsening. In conclusion, for practical work on Pd-Cu-Ga-Zn alloys, the oxidation treatment followed by ice-quenching instead of slow cooling is recommended for the simultaneous oxidation and hardening effects on the alloy.

This study examined the effect of the cooling rate on the hardness and its effect on the microstructure during porcelain firing simulation of a Pd-Ag-In-Sn-Ga metal-ceramic alloy. In practice, after each firing step for porcelain bonding, the prosthesis is cooled to room temperature before proceeding to the next firing step. The cooling step is known to allow the hardness of the metal substructure to increase. The aim of the study was to determine whether controlling the cooling rate after each porcelain-firing step increases the hardness of the Pd-Ag-based metal-ceramic alloy. The results showed that the hardness of specimens cooled at a higher cooling rate increased after each firing step compared to specimens cooled at a lower cooling rate (p 0.05). During cooling after the firing simulation the InPd

The pearl-spot damsel, Chromis notata, is one of the important fishery species in Korea. While C. notata has been commonly harvested in southern Korea, the increasing number of C. notata in higher latitudes has crucial ecological, economic and evolutionary implications under conditions where the climate is rapidly changing. Here we examined the morphological and genetic characteristics of C. notata to assess patterns of geographical variations among the groups from three different sites. The groups were clearly distinguishable in the analysis of morphological characteristics. On the other hand, the groups were genetically indistinguishable. All individuals fell within a single clade in the neighbor-joining tree but appeared scattered in the haplotype network. Several haplotypes are shared among the sampling sites (Jejudo-Ulleungdo; Hap 9, Wangdolcho-Ulleungdo; Hap 28, Hap 33, Hap 34). Although control region markers did not elucidate the spatial patterns in genetic characteristics, Wangdolcho and Ulleungdo groups appear to exhibit a more robust gene flow between the two groups than with Jejudo group. Integrative approaches such as those combining morphological and genetic analyses minimize potential errors caused by limited perspectives of each analysis and can provide useful information for discovering functional DNA regions attributable to morphological characteristics expressions.

This study examined the effect of ice-quenching after degassing on the change in hardness of a Pd-Au-Zn alloy during porcelain firing simulations. By ice-quenching after degassing, the specimens were softened due to homogenization without the need for an additional softening heat treatment. The lowered hardness by ice-quenching after degassing was recovered greatly from the first stage of porcelain firing process by controlling the cooling rate. The increase in hardness during cooling after porcelain firing was attributed to the precipitation of the f.c.t. PdZn phase containing Au, which caused severe lattice strain in the interphase boundary between the precipitates and matrix of the f.c.c. structure. The final hardness was slightly higher in the ice-quenched specimen than in the specimen cooled at stage 0 (the most effective cooling rate for alloy hardening) after degassing. This was attributed to the more active grain interior precipitation during cooling in the ice-quenched specimen after degassing.

Introduction IL-1β signalling has a critical role in the pathogenesis of various types of inflammatory arthritis including rheumatoid arthritis (RA). We aimed to investigate the therapeutic effects of human IL-1 receptor antagonist with Fc fragment (hIL-1Ra-Fc) on autoimmune arthritis and to identify the possible mechanisms by which hIL-1RA-Fc exerts anti-arthritic effects in a murine model of RA and patients with rheumatoid arthritis. Methods Collagen-induced arthritis (CIA) murine model was established in DBA/1J mice. The levels of various cytokines were determined by using enzyme-linked immunosorbent assay. The mouse joints were assessed for clinical arthritis score and histologic features. Th17 cells and Treg cells were stained by using antibodies specific for CD4, IL-17, CD25, and FoxP3. Osteoclastogenesis was determined by TRAP staining and real-time PCR. Results hIL-1RA-Fc reduced the arthritis incidence, histological inflammation and cartilage score in the CIA model. The expression of proinflammatory cytokines, VEGF and RANK, was reduced in the affected joint of hIL-1Ra-Fc-treated mice. hIL-1Ra-Fc-treated mice showed decreased number of Th17 cells with increased number of Treg cells in spleens. hIL-1Ra-Fc reduced Th17 cell differentiation by inactivation of STAT3 signalling, and reciprocally induced Treg cell differentiation through STAT5 signalling. In addition, the expression of IL-17, TNF-α, RANKL, and VEGF was decreased, while Foxp3 gene expression was increased in PBMCs of RA patients after administration of hIL-1Ra-Fc. Conclusion The anti-arthritis effects of hIL-1RA-Fc are associated with regulation of balance between Th17 cells and Treg cells and suppression of osteoclastogenesis and angiogenesis in the affected joints.

Cephalosporin acylase (CA), a member of the N-terminal nucleophile hydrolase family, is activated through sequential primary and secondary autoproteolytic reactions with the release of a pro segment. We have determined crystal structures of four CA mutants. Two mutants are trapped after the primary cleavage, and the other two undergo secondary cleavage slowly. These structures provide a look at pro-segment conformation during activation in N-terminal nucleophile hydrolases. The highly strained helical pro segment of precursor is transformed into a relaxed loop in the intermediates, suggesting that the relaxation of structural constraints drives the primary cleavage reaction. The secondary autoproteolytic step has been proposed to be intermolecular. However, our analysis provides evidence that CA is processed in two sequential steps of intramolecular autoproteolysis involving two distinct residues in the active site, the first a serine and the second a glutamate.

Topoisomerase IV is involved in topological changes in the bacterial genome using the free energy from ATP hydrolysis. Its functions are the decatenation of daughter chromosomes following replication by DNA relaxation and double-strand DNA breakage. In this study, the N-terminal fragment of the topoisomerase IV ParE subunit from Xanthomonas oryzae pv. oryzae was overexpressed in Escherichia coli, purified and crystallized. Diffraction data were collected to 2.15 A resolution using a synchrotron-radiation source. The crystal belonged to space group P4(2)2(1)2, with unit-cell parameters a = b = 105.30, c = 133.76 A. The asymmetric unit contains one molecule, with a corresponding V(M) of 4.21 A(3) Da(-1) and a solvent content of 69.6%.

Cephalosporin acylase (CA), a member of the N-terminal nucleophile hydrolase family, is activated through two steps of intramolecular autoproteolysis, the first mediated by a serine residue, and the second by a glutamate, which releases the pro-segment and produces an active enzyme. In this study, we have determined the crystal structures of mutants which could affect primary or secondary auto-cleavage and of sequential intermediates of a slow-processing mutant at 2.0-2.5A resolutions. The pro-segments of the mutants undergo dynamic conformational changes during activation and adopt surprisingly different loop conformations from one another. However, the autoproteolytic site was found to form a catalytically competent conformation with a solvent water molecule, which was essentially conserved in the CA mutants.

The crystal structure of recombinant ferritin from Helicobacter pylori has been determined in its apo, low-iron-bound, intermediate, and high-iron-bound states. Similar to other members of the ferritin family, the bacterial ferritin assembles as a spherical protein shell of 24 subunits, each of which folds into a four-alpha-helix bundle. Significant conformational changes were observed at the BC loop and the entrance of the 4-fold symmetry channel in the intermediate and high-iron-bound states, whereas no change was found in the apo and low-iron-bound states. The imidazole rings of His149 at the channel entrance undergo conformational changes that bear resemblance to heme configuration and are directly coupled to axial translocation of Fe ions through the 4-fold channel. Our results provide the first structural evidence of the translocation of Fe ions through the 4-fold channel in prokaryotes and the transition from a protein-dominated process to a mineral-surface-dominated process during biomineralization.