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Bracket bonding to polymethylmethacrylate-based materials for computer-aided design/manufacture of temporary restorations: Influence of mechanical treatment and chemical treatment with universal adhesives

  • Goracci, Cecilia;Ozcan, Mutlu;Franchi, Lorenzo;Di Bello, Giuseppe;Louca, Chris;Vichi, Alessandro
    • The korean journal of orthodontics
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    • v.49 no.6
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    • pp.404-412
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    • 2019
  • Objective: To assess shear bond strength and failure mode (Adhesive Remnant Index, ARI) of orthodontic brackets bonded to polymethylmethacrylate (PMMA) blocks for computer-aided design/manufacture (CAD/CAM) fabrication of temporary restorations, following substrate chemical or mechanical treatment. Methods: Two types of PMMA blocks were tested: $CAD-Temp^{(R)}$ (VITA) and $Telio^{(R)}$ CAD (Ivoclar-Vivadent). The substrate was roughened with 320-grit sandpaper, simulating a fine-grit diamond bur. Two universal adhesives, Scotchbond Universal Adhesive (SU) and Assure Plus (AP), and a conventional adhesive, Transbond XT Primer (XTP; control), were used in combination with Transbond XT Paste to bond the brackets. Six experimental groups were formed: (1) $CAD-Temp^{(R)}/SU$; (2) $CAD-Temp^{(R)}/AP$; (3) $CAD-Temp^{(R)}/XTP$; (4) $Telio^{(R)}$ CAD/SU; (5) $Telio^{(R)}$ CAD/AP; (6) $Telio^{(R)}$ CAD/XTP. Shear bond strength and ARI were assessed. On 1 extra block for each PMMA-based material surfaces were roughened with 180-grit sandpaper, simulating a normal/medium-grit ($100{\mu}m$) diamond bur, and brackets were bonded. Shear bond strengths and ARI scores were compared with those of groups 3, 6. Results: On $CAD-Temp^{(R)}$ significantly higher bracket bond strengths than on $Telio^{(R)}$ CAD were recorded. With XTP significantly lower levels of adhesion were reached than using SU or AP. Roughening with a coarser bur resulted in a significant increase in adhesion. Conclusions: Bracket bonding to CAD/CAM PMMA can be promoted by grinding the substrate with a normal/medium-grit bur or by coating the intact surface with universal adhesives. With appropriate pretreatments, bracket adhesion to CAD/CAM PMMA temporary restorations can be enhanced to clinically satisfactory levels.

Full scale tests of RC joints with minor to moderate seismic damage repaired using C-FRP sheets

  • Karayannis, Chris G.;Golias, Emmanuil
    • Earthquakes and Structures
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    • v.15 no.6
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    • pp.617-627
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    • 2018
  • After earthquakes FRP sheets are often used for the rehabilitation of damaged Reinforced Concrete (RC) beamcolumn connections. Connections with minor to moderate damage are often dealt with by applying FRP sheets after a superficial repair of the cracks using resin paste or high strength mortar but without infusion of thin resin solution under pressure into the cracking system. This technique is usually adopted in these cases due to the fast and easy-to-apply procedure. The experimental investigation reported herein aims at evaluating the effectiveness of repairing the damaged beam-column connections using FRP sheets after a meticulous but superficial repair of their cracking system using resin paste. The investigation comprises experimental results of 10 full scale beam-column joint specimens; five original joints and the corresponding retrofitted ones. The repair technique has been applied to RC joints with different joint reinforcement arrangements with minor to severe damage brought about by cyclic loading for the purposes of this work. Aiming at quantitative concluding remarks about the effectiveness of the repair technique, data concerning response loads, loading stiffness and energy absorption values have been acquired and commented upon. Furthermore, comparisons of damage index values and values of equivalent viscous damping, as obtained during the test of the original specimens, with the corresponding ones observed in the loading of the repaired ones have also been evaluated and commented. Based on these comparisons, it is deduced that the technique under investigation can be considered to be a rather satisfactory repair technique for joints with minor to moderate damage taking into account the rapid, convenient and easy-to-apply character of its application.

Enhancement of fluid flow performance through deep fractured rocks in an insitu leaching potential mine site using discrete fracture network (DFN)

  • Yao, Wen-li;Mostafa, Sharifzadeh;Ericson, Ericson;Yang, Zhen;Xu, Guang;Aldrich, Chris
    • Geomechanics and Engineering
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    • v.18 no.6
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    • pp.585-594
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    • 2019
  • In-situ leaching could be one of the promising mining methods to extract the minerals from deep fractured rock mass. Constrained by the low permeability at depth, however, the performance does not meet the expectation. In fact, the rock mass permeability mainly depends on the pre-existing natural fractures and therefore play a crucial role in in-situ leaching performance. More importantly, fractures have various characteristics, such as aperture, persistence, and density, which have diverse contributions to the promising method. Hence, it is necessary to study the variation of fluid rate versus fracture parameters to enhance in-situ leaching performance. Firstly, the subsurface fractures from the depth of 1500m to 2500m were mapped using the discrete fracture network (DFN) in this paper, and then the numerical model was calibrated at a particular case. On this basis, the fluid flow through fractured rock mass with various fracture characteristics was analyzed. The simulation results showed that with the increase of Fisher' K value, which determine the fracture orientation, the flow rate firstly decreased and then increased. Subsequently, as another critical factor affecting the fluid flow in natural fractures, the fracture transmissivity has a direct relationship with the flow rate. Sensitive study shows that natural fracture characteristics play a critical role in in-situ leaching performance.

Effect of in ovo feeding of γ-aminobutyric acid combined with embryonic thermal manipulation on hatchability, growth, and hepatic gene expression in broilers

  • Chris Major, Ncho;Akshat, Goel;Vaishali, Gupta;Chae-Mi, Jeong;Yang-Ho, Choi
    • Animal Bioscience
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    • v.36 no.2
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    • pp.284-294
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    • 2023
  • Objective: This study investigated the effects of in ovo feeding of γ-aminobutyric acid (GABA) and embryonic thermal manipulation (ETM) on growth performance, organ indices, plasma biochemical parameters, hepatic antioxidant levels, and expression of lipid metabolism-related genes in broilers. Methods: Two hundred and fifty eggs were assigned to one of four treatments: control eggs incubated under standard conditions (CON); eggs that received an in ovo injection of 10% GABA on day 17.5 of incubation (G10); thermally manipulated eggs between days 10 and 18 of incubation at 39.6°C for 6 h daily (TM); and eggs that received both treatments during incubation (G10+TM). After 28 days of rearing, five birds per treatment were selected for blood and organ sampling. Results: No differences were found in hatchability or growth parameters among different treatment groups. Hepatic gene expression of catalase (CAT) and glutathione peroxidase 1 (GPx1) was upregulated (p = 0.046 and p = 0.006, respectively) in the G10+TM group, while that of nuclear factor erythroid 2-related factor 2 (NRF2) was upregulated (p = 0.039) in the G10 group. In addition, the relative gene expression of NADPH oxidase 1 (NOX1) was significantly lower (p = 0.007) in all treatment groups than that in the CON group. Hepatic fatty acid synthase (FAS) levels and average daily feed intake (ADFI) of last week showed a positive correlation (r = 0.50, p = 0.038). In contrast, the relative gene expression of the extracellular fatty acid-binding protein (EXFAB) and peroxisome proliferator-activated receptor-γ (PPAR-γ) were positively correlated (r = 0.48, p = 0.042 and r = 0.50, p = 0.031) with the overall ADFI of birds. Conclusion: Taken together, the results of this study suggest that the combination of in ovo feeding of GABA and ETM can enhance hepatic antioxidant function in broilers.

Revision after Instability Surgery (수술 후 재발한 견관절 불안정증의 치료)

  • Kim, Paul Shinil;Jo, Chris Hyunchul
    • Journal of the Korean Orthopaedic Association
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    • v.55 no.5
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    • pp.374-382
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    • 2020
  • Recurrence is the most common complication after shoulder instability surgery, and the main causes of the postoperative recurrence of instability are trauma, misdiagnosis, and technical errors. The risk factors of recurrence may be classified as patient related, anatomical or technical. Causes of failure should be thoroughly evaluated by meticulous history taking, physical examination, and imaging studies, and followed by proper treatment of pathologic lesions. Nonoperative treatment should be considered initially in cases of recurred instability after shoulder instability surgery, but if this fails, repeated recurrence is prevented by performing appropriate anatomical reconstruction of ruptured Bankart lesions, capsular laxities, glenoid deficiencies and humeral head bone defects.

Prognostic factors affecting structural integrity after arthroscopic rotator cuff repair: a clinical and histological study

  • Pei Wei Wang;Chris Hyunchul Jo
    • Clinics in Shoulder and Elbow
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    • v.26 no.1
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    • pp.10-19
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    • 2023
  • Background: Tendon degeneration contributes to rotator cuff tears; however, its role in postoperative structural integrity is poorly understood. The purpose of this study was to investigate the factors associated with postoperative structural integrity after rotator cuff repair, particularly focusing on the histology of tendons harvested intraoperatively. Methods: A total of 56 patients who underwent primary arthroscopic rotator cuff repair between 2009 and 2011 were analyzed. A 3-mm-diameter sample of supraspinatus tendons was harvested en bloc from each patient after minimal debridement of the torn ends. Tendon degeneration was assessed using seven histological parameters on a semi-quantitative grading scale, and the total degeneration score was calculated. One-year postoperative magnetic resonance imaging was used to classify the patients based on retear. Results: The total degeneration scores in the healed and retear groups were 13.93±2.03 and 14.08±2.23 (P=0.960), respectively. Arthroscopically measured anteroposterior (AP) tear sizes in the healed and retear groups were 24.30±12.35 mm and 36.42±25.23 mm (P=0.026), respectively. Preoperative visual analog scale pain scores at rest in the healed and retear groups were 3.54±2.37 and 5.16±2.16 (P=0.046), respectively. Retraction sizes in the healed and retear groups were 16.02±7.587 mm and 22.33±13.364 mm (P=0.037), respectively. The odds of retear rose by 4.2% for every 1-mm increase in AP tear size (P=0.032). Conclusions: The postoperative structural integrity of the rotator cuff tendon was not affected by tendon degeneration, whereas the arthroscopically measured AP tear size of the rotator cuff tendon was an independent predictor of retear. Level of evidence: III.

Discovery of a Radio Relic in the Massive Merging Cluster SPT-CL J2023-5535 from the ASKAP-EMU Pilot Survey

  • Kim, HyeongHan;Jee, M. James;Rudnick, Lawrence;Parkinson, David;Finner, Kyle;Yoon, Mijin;Lee, Wonki;Brunetti, Giangranco;Bruggen, Marcus;Collier, Jordan D.;Hopkins, Andrew M.;Michalowski, Michal J.;Norris, Ray P.;Riseley, Chris
    • The Bulletin of The Korean Astronomical Society
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    • v.45 no.1
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    • pp.30.1-30.1
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    • 2020
  • The ASKAP-EMU survey is a deep wide-field radio continuum survey designed to cover the entire southern sky and a significant fraction of the northern sky up to +30°. Here, we report a discovery of a radio relic in the merging cluster SPT-CL J2023-5535 at z=0.23 from the ASKAP-EMU pilot 300 square degree survey (800-1088 MHz). The deep high-resolution data reveal a ~2 Mpc-scale radio halo elongated in the east-west direction, coincident with the intracluster gas. The radio relic is located at the western edge of this radio halo stretched ~0.5 Mpc in the north-south orientation. The integrated spectral index of the radio relic within the narrow bandwidth is α1088MHz800MHz = -0.76 ± 0.06. Our weak-lensing analysis shows that the system is massive (M200 = 1.04 ± 0.36 × 1015M⊙) and composed of at least three subclusters. We suggest a scenario, wherein the radio features arise from the collision between the eastern and middle subclusters. Furthermore, the direct link between the local AGN and the relic along with the discontinuities in X-ray observation hint us that we are looking at the site of re-acceleration.

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Dietary supplementation of solubles from shredded, steam-exploded pine particles modulates cecal microbiome composition in broiler chickens

  • Chris Major Ncho;Akshat Goel;Vaishali Gupta;Chae-Mi Jeong;Ji-Young Jung;Si-Young Ha;Jae-Kyung Yang;Yang-Ho Choi
    • Journal of Animal Science and Technology
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    • v.65 no.5
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    • pp.971-988
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    • 2023
  • This study evaluated the effects of supplementing solubles from shredded, steam-exploded pine particles (SSPP) on growth performances, plasma biochemicals, and microbial composition in broilers. The birds were reared for 28 days and fed basal diets with or without the inclusion of SSPP from 8 days old. There were a total of three dietary treatments supplemented with 0% (0% SSPP), 0.1% (0.1% SSPP) and 0.4% (0.4% SSPP) SSPP in basal diets. Supplementation of SSPP did not significantly affect growth or plasma biochemicals, but there was a clear indication of diet-induced microbial shifts. Beta-diversity analysis revealed SSPP supplementation-related clustering (ANOSIM: r = 0.31, p < 0.01), with an overall lower (PERMDISP: p < 0.05) individual dispersion in comparison to the control group. In addition, the proportions of the Bacteroides were increased, and the relative abundances of the families Vallitaleaceae, Defluviitaleaceae, Clostridiaceae, and the genera Butyricicoccus and Anaerofilum (p < 0.05) were significantly higher in the 0.4% SSPP group than in the control group. Furthermore, the linear discriminant analysis effect size (LEfSe) also showed that beneficial bacteria such as Ruminococcus albus and Butyricicoccus pullicaecorum were identified as microbial biomarkers of dietary SSPP inclusion (p < 0.05; | LDA effect size | > 2.0). Finally, network analysis showed that strong positive correlations were established among microbial species belonging to the class Clostridia, whereas Erysipelotrichia and Bacteroidia were mostly negatively correlated with Clostridia. Taken together, the results suggested that SSPP supplementation modulates the cecal microbial composition of broilers toward a "healthier" profile.

Identification of the mechanism for dehalorespiration of monofluoroacetate in the phylum Synergistota

  • Lex E. X. Leong;Stuart E. Denman;Seungha Kang;Stanislas Mondot;Philip Hugenholtz;Chris S. McSweeney
    • Animal Bioscience
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    • v.37 no.2_spc
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    • pp.396-403
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    • 2024
  • Objective: Monofluoroacetate (MFA) is a potent toxin that blocks ATP production via the Krebs cycle and causes acute toxicity in ruminants consuming MFA-containing plants. The rumen bacterium, Cloacibacillus porcorum strain MFA1 belongs to the phylum Synergistota and can produce fluoride and acetate from MFA as the end-products of dehalorespiration. The aim of this study was to identify the genomic basis for the metabolism of MFA by this bacterium. Methods: A draft genome sequence for C. porcorum strain MFA1 was assembled and quantitative transcriptomic analysis was performed thus highlighting a candidate operon encoding four proteins that are responsible for the carbon-fluorine bond cleavage. Comparative genome analysis of this operon was undertaken with three other species of closely related Synergistota bacteria. Results: Two of the genes in this operon are related to the substrate-binding components of the glycine reductase protein B (GrdB) complex. Glycine shares a similar structure to MFA suggesting a role for these proteins in binding MFA. The remaining two genes in the operon, an antiporter family protein and an oxidoreductase belonging to the radical S-adenosyl methionine superfamily, are hypothesised to transport and activate the GrdB-like protein respectively. Similar operons were identified in a small number of other Synergistota bacteria including type strains of Cloacibacillus porcorum, C. evryensis, and Pyramidobacter piscolens, suggesting lateral transfer of the operon as these genera belong to separate families. We confirmed that all three species can degrade MFA, however, substrate degradation in P. piscolens was notably reduced compared to Cloacibacillus isolates possibly reflecting the loss of the oxidoreductase and antiporter in the P. piscolens operon. Conclusion: Identification of this unusual anaerobic fluoroacetate metabolism extends the known substrates for dehalorespiration and indicates the potential for substrate plasticity in amino acid-reducing enzymes to include xenobiotics.

Florid Reactive Periostitis of the Clavicle: A Case Report (쇄골에 발생한 개화성 반응성 골막염: 증례 보고)

  • Hye Eun Park;Jee Won Chai;Chris Hyunchul Jo;Ji Eun Kim;Dong Hyun Kim;Hyo Jin Kim;Jiwoon Seo
    • Journal of the Korean Society of Radiology
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    • v.83 no.2
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    • pp.414-419
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    • 2022
  • Florid reactive periostitis (FRP) is a rare benign fibro-osseous proliferation, occurring mostly in the short tubular bones of hands and rarely in the long tubular bones. We report a surgically confirmed case of FRP involving the clavicle in a 26-year-old male. On MRI scans, a soft tissue mass with T2 high signal intensity was found that originated from the periosteum of the clavicle and included surrounding a periosteal elevation and perilesional soft tissue edema. Strong contrast enhancement was noted inside the mass and along the periosteum involving more than half of the circumference of the clavicle. Serial radiographs revealed a soft tissue mass without mineralization that turned into an ossified mass with a solid periosteal reaction within a month.