110 research outputs found

    Gelatin-layered and multi-sized porous β-tricalcium phosphate for tissue engineering scaffold

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    The multi-sized porous β-tricalcium phosphate scaffolds were fabricated by freeze drying followed by slurry coating using a multi-sized porous sponge as a template. Then, gelatin was dip coated on the multi-sized porous β-tricalcium phosphate scaffolds under vacuum. The mechanical and biological properties of the fabricated scaffolds were evaluated and compared to the uniformly sized porous scaffolds and scaffolds that were not coated by gelatin. The compressive strength was tested by a universal testing machine, and the cell viability and differentiation behavior were measured using a cell counting kit and alkaline phosphatase activity using the MC3T3-E1 cells. In comparison, the gelatin-coated multi-sized porous β-tricalcium phosphate scaffold showed enhanced compressive strength. After 14 days, the multi-sized pores were shown to affect cell differentiation, and gelatin coatings were shown to affect the cell viability and differentiation. The results of this study demonstrated that the multi-sized porous β-tricalcium phosphate scaffold coated by gelatin enhanced the mechanical and biological strengths

    The Evaluation of Osseointegration of Dental Implant Surface with Different Size of TiO 2

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    With the development of nanotechnology, many researches have shown that nanometer-scaled materials especially TiO2 nanotube have a positive effect on cellular behavior and surface characteristics of implant, which are considered to be crucial factors in osseointegration. However, it has not yet been verified which nanotube size is effective in osseointegration in vivo. The aim of this study was to evaluate the effect of implant surface-treated with different size of TiO2 nanotubes on osseointegration in rat femur. The customized implants (threaded and nonthreaded type), surface-treated with different diameter of TiO2 nanotubes (30 nm, 50 nm, 70 nm, and 100 nm nanotube), were placed on both sides of the femur of 50 male Sprague-Dawley rats (6 weeks old). Rats were sacrificed at 2 and 6 weeks following surgery; then the specimens were collected by perfusion fixation and the osseointegration of implants was evaluated by radiographic and histologic analyses and removal torque value test. The mean of bone area (%) and the mean of removal torque were different in each group, indicating that the difference in TiO2 nanotube size may influence new bone formation and osseointegration in rats

    Inter-arm arterial pressure difference caused by prone position in the thoracic outlet syndrome patient -A case report-

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    Thoracic outlet syndrome has neurologic symptoms caused by compression of brachial plexus, blood vessel symptoms are caused by compression of the artery or vein. The authors report a case of sudden decrease in blood pressure of the left arm after turning the patient from supine position to prone position. They confirmed that the patient had thoracic outlet syndrome after performing computed tomography

    Lambert-Eaton myasthenic syndrome as a cause of persistent neuromuscular weakness after a mediastinoscopic biopsy -A case report-

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    There are many causes of prolonged postoperative muscle weakness, including drugs, residual anesthetics, cerebrovascular events, electrolyte imbalance, hypothermia, and neuromuscular disease. Neuromuscular diseases are relatively rare, with the most common being myasthenia gravis and Lambert-Eaton myasthenic syndrome (LEMS). We report an unusual case in which a patient who was given a muscle relaxant during mediastinoscopy developed postoperative muscle weakness that was ultimately diagnosed as secondary to LEMS

    Multi-messenger observations of a binary neutron star merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

    Search for High-energy Neutrinos from Binary Neutron Star Merger GW170817 with ANTARES, IceCube, and the Pierre Auger Observatory

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    Multi-messenger Observations of a Binary Neutron Star Merger

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    On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ȯ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∼ 9 and ∼ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.</p

    Cytotoxicity Test of One-Step Self-Etching Bonding Agents by Standardized Dentin Barrier Test Using Polyurethane Discs

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    This study was performed to standardize a dentin barrier test with the substitute and evaluate the cytotoxicity of one-step self-etching bonding agents. Each of the natural bovine dentin and polyurethane discs were 500-μm thick and were tested using a perfusion device. Following the treatment with 0.05% phenol on the natural bovine disc or three kinds of polyurethane discs—30, 40, and 50 pcf (pounds per cubic foot)—cell viability of L-929 was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and expressed as percentages of non-treated group, respectively. A substitute showing permeability similar to that of bovine dentin was determined based on this result. Cytotoxicity test of bonding agents was performed by the selected substitute, the results of which were expressed as percentages of the control. In addition, SEM images were taken after the tests. The cell viability by 40-pcf polyurethane disc was not statistically different from that by bovine dentin disc (P &gt; 0.05). Futurabond DC resulted in the highest cell viability and Bond force the lowest by the 40-pcf polyurethane disc (P &lt; 0.05). The adhesives on the 40-pcf polyurethane disc changed cellular morphology with different degrees on the SEM images. This standardized test might be useful for assessing the cytotoxicity of dental materials applied to dentin before clinical applications
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