The effect of surface roughness of ceramic-polymer CAD/CAM blocks on the mechanical properties was investigated in this study. Commercially available Polyglass (Vericom, Korea) and Enamic (Vita, Germany) were selected for this purpose. They were cut into either (4.0×2.1×17.0) mm and (3.0×4.0×17.0) mm, followed by grinding, and polished sequentially with 6 µm and 1 µm diamond paste. Flexural strength, fracture toughness, and Weibull analysis were determined according to ISO 6872 Dentistry-Ceramic materials. The elastic moduli were calculated from a stress-strain curves under flexural loading. The statistical significances of the mechanical properties between the products and surface roughness were analyzed with ANOVA and pared t-test at a significance level of 0.05. After grinding with 6 µm diamond paste after cutting by observing with an atomic force microscope, the arithmetic average roughness decreased to 47~49% and the maximum roughness decreased to 68~69%. When polishing with 1 µm diamond paste, The average roughness decreased to 13~22% and the maximum roughness decreased to 16~19%. When the flexural load was applied, stress increased linearly and fractured without plastic deformation both Polyglass and Enamic. As the surface roughness decreased, the mechanical properties were increased both Polyglass and Enamic. However, the mechanical properties of Polyglass increased up to P3, while Enamic showed almost maximal values at E2, after that there was no significant differences between E2 and E3. It could be due to the different microstructure between two blocks used in this experiment.
Diamond ; Plastics

The objective of this study was to fabricate Zr-Cu alloys with low elastic modulus and low magnetic susceptibility for the use as the dental biomaterials. Metallic implants, such as stainless steel, Co-Cr alloys, and Ti alloys, could be magnetized in the strong magnetic field of the MRI instrument and produce artifacts (magnetic susceptibility artifacts) on the image. The areas that cause the artifacts on images are closely related to the magnetic susceptibility. This susceptibility artifact is caused by metals, such as Ti, Co, and stainless steels, inside the body. Therefore, metallic implants with a low magnetic susceptibility are preferable for surgery performed with the assistance of an MRI. Recently, Zr-based alloys have been attracting interests as biomaterials due to their excellent mechanical properties and low magnetic susceptibility. The magnetic susceptibility of Zr-Nb was half that of Ti-6Al-4V. In addition, the magnetic susceptibility of Zr-Mo was reported almost one-third that of commercially pure Ti and Ti-6Al-4V alloy.However, there are limited reports concerning metallic biomaterials with low magnetic susceptibility for dental applications. The magnetic susceptibility of the Zr-Cu binary alloys was extremely low, approximately 10-7 ; this level is approximately one order less than that of pure Zr and other commercialized Ti-based metallic biomaterials. The Zr-Cu binary alloy exhibited moderate compressive strength (1261~1565 MPa), yield stress (432~595 MPa), favorable elongation (14~34%), high elastic energy (7.2~19.3 MJ/㎥ ) and low elastic modulus (20~28 GPa). Consequently, Zr-Cu binary alloys have the potential to be used as biomaterials with nullifying magnetic properties for magnetic resonance imaging diagnosis and a good combination of mechanical properties indicates them potential biomaterials for biological hard tissue materials

The objective of this study was to fabricate Zr-Cu alloys with low elastic modulus and low magnetic susceptibility for the use as the dental biomaterials. Metallic implants, such as stainless steel, Co-Cr alloys, and Ti alloys, could be magnetized in the strong magnetic field of the MRI instrument and produce artifacts (magnetic susceptibility artifacts) on the image. The areas that cause the artifacts on images are closely related to the magnetic susceptibility. This susceptibility artifact is caused by metals, such as Ti, Co, and stainless steels, inside the body. Therefore, metallic implants with a low magnetic susceptibility are preferable for surgery performed with the assistance of an MRI. Recently, Zr-based alloys have been attracting interests as biomaterials due to their excellent mechanical properties and low magnetic susceptibility. The magnetic susceptibility of Zr-Nb was half that of Ti-6Al-4V. In addition, the magnetic susceptibility of Zr-Mo was reported almost one-third that of commercially pure Ti and Ti-6Al-4V alloy.However, there are limited reports concerning metallic biomaterials with low magnetic susceptibility for dental applications. The magnetic susceptibility of the Zr-Cu binary alloys was extremely low, approximately 10-7 ; this level is approximately one order less than that of pure Zr and other commercialized Ti-based metallic biomaterials. The Zr-Cu binary alloy exhibited moderate compressive strength (1261~1565 MPa), yield stress (432~595 MPa), favorable elongation (14~34%), high elastic energy (7.2~19.3 MJ/㎥ ) and low elastic modulus (20~28 GPa). Consequently, Zr-Cu binary alloys have the potential to be used as biomaterials with nullifying magnetic properties for magnetic resonance imaging diagnosis and a good combination of mechanical properties indicates them potential biomaterials for biological hard tissue materials

Bronchial foreign body aspirations are uncommon in adults and usually have various underlying conditions, otherwise accidentally occurred in dental procedure, medical, surgical procedure. The most commonly aspirated objects were food materials, with peanuts leading the list. When bronchial foreign body was aspirated, no definite respiratory symptoms or foreign body is may not seen, then diagnosis is delayed. Therefore late complications was developed. The tendency to use fiberoptic bronchoscope for removal of foreign bodies in adults is increased. We report a rare case of bronchial pneumonia due to occult aspiration of a twig before 1 year with a review of the literatures.
Adult ; Arachis ; Aspirations (Psychology) ; Bronchopneumonia ; Bronchoscopes ; Diagnosis ; Foreign Bodies ; Humans ; Pneumonia*

Tigers are one of the most endangered species over the world and protected internationally or locally. However, they are still traded illegally for the Traditional East Asia Medicine or souvenirs / mementos as well as fake products. In the present study, to identify the species of the specimen known as the tiger's genitalia that was sold for mementos in China, two approaches of genetic tools and morphological comparisons were applied. On the basis of the entire sequences of mitochondrial cytochrome b gene (1,140 bp), the result of nucleotide comparisons showed that the specimen examined here is matched with banteng, Bos javanicus (Identities = 1,138/1,140; 99%). In addition, the examination of external morphological characters revealed that the genitalia of the specimen is much more similar to the one of cows, not to tigers. The outcomes highlighted that there are still some fake products of tigers traded in market and molecular genetic tools could help identifying species of wildlife products.
Base Sequence* ; China ; Cytochromes b ; DNA* ; Endangered Species ; Genitalia ; Medicine, East Asian Traditional ; Molecular Biology ; Sequence Analysis, DNA* ; Tigers*

BACKGROUND: Pleural effusion is one of most common clinical mainifestations associated with a variety of pulmonary disease such as malignancy, tuberculosis, and pneumonia. However, there are no useful laboratory tests to determine the specific cause of pleural effusion. Therefore, an attempt was made to analyze the various types of pleural effusion and search for useful laboratory tests for pleural effusion in order to differentiate between the disease, especially between a malignant pleural effusion and a non-malignant pleural effusion. METHODS: 93 patients with a pleural effusion, who visited the Severance hospital from January 1998 to August 1999, were enrolled in this study. Ultrasound-guided thoracentesis was done and a confirmational diagnosis was made by a gram stain, bacterial culture, Ziehl-Neelsen stain, a mycobacterial culture, a pleural biopsy and cytology. RESULTS: The male to female ratio was 56:37 and the average age was 47.1±21.8 years. There were 16 cases with a malignant effusion, 12 cases with a para-malignant effusion, 36 cases with tuberculosis, 22 cases with a para-pneumonic effusion, and 7 cases with transudate. The LDH2 fraction was significantly higher in the para-malignant effusion group compared to the para-pneumonic effusion group [30.6±64.% and 20.2±7.5%, respectively (p<0.05)] and both the LDH and LDH2 fraction was significantly in the para-malignant effusion group compared to those with tuberculosis [16.4±7.2% vs. 7.6±4.7%, and 30.6±6.4% vs. 17.6±6.3% respectively (p<0.05)]. The pleural effusion/serum LDH4 fraction ratio was significantly lower in the malignant effusion group compared to those with tuberculosis [1.5±0.8 vs. 2.1±0.6, respectively (p<0.05)]. The LDH4 fraction and the pleural effusion/serum LDH4 fraction ratio was significantly lower in the para-malignant effusion group compared to those with tuberculosis [17.0±5.8% vs. 23.5±4.6% and 1.3±0.4 vs. 2.1±0.6, respectively(p<0.05)]. CONCLUSION: These results suggest that the LDH isoenzyme was the only useful biochemical test for a differential diagnosis of the various disease. In particular, the most useful test was the pleural effusion/serum LDH4 fraction ratio to distinguish between a para-malignant effusion and a tuberculous effusion.
Biopsy ; Diagnosis ; Diagnosis, Differential* ; Exudates and Transudates ; Female ; Humans ; Lung Diseases ; Male ; Pleural Effusion* ; Pleural Effusion, Malignant ; Pneumonia ; Tuberculosis

Scrapie is a mammalian transmissible spongiform encephalopathy or prion disease that predominantly affects sheep and goats. Scrapie has been shown to overcome the species barrier via experimental infection of other rodents. To confirm the re-transmissibility of the mouse-adapted ME7 scrapie strain to ovine prion protein (PrP) transgenic mice, mice of an ovinized transgenic mouse line carrying the Suffolk sheep PrP gene that contained the A₁₃₆ R₁₅₄ Q₁₇₁/ARQ allele were intracerebrally inoculated with brain homogenates obtained from terminally ill ME7-infected C57BL/6J mice. Herein, we report that the mouse-adapted ME7 scrapie strain was successfully re-transmitted to the transgenic mice expressing ovine PrP. In addition, we observed changes in the incubation period, glycoform profile, and pattern of scrapie PrP (PrP(Sc)) deposition in the affected brains. PrP(Sc) deposition in the hippocampal region of the brain of 2nd-passaged ovine PrP transgenic mice was accompanied by plaque formation. These results reveal that the mouse-adapted ME7 scrapie strain has the capacity to act as a template for the conversion of ovine normal monomeric precursors into a pathogenic form in ovine PrP transgenic mice. The change in glycoform pattern and the deposition of plaques in the hippocampal region of the brain of the 2nd-passaged PrP transgenic mice are most likely cellular PrP species dependent rather than being ME7 scrapie strain encoded.
Alleles ; Animals ; Brain ; Gliosis ; Goats ; Humans ; Mice ; Mice, Transgenic ; Plaque, Amyloid ; Prion Diseases ; PrPSc Proteins ; Rodentia ; Scrapie ; Sheep ; Terminally Ill

PURPOSE: The aim of this study was to determine whether the ERCC1 expression is effective to predict the clinical outcomes of patients with advanced gastric cancer (AGC) and who were treated with cisplatin-based first-line chemotherapy. MATERIALS AND METHODS: A total of 89 measurable AGC patients received cisplatin and capecitabine, with or without epirubicin, as a part of a randomized phase II study. Patients were included for the current molecular analysis if they had received two or more cycles of chemotherapy, their objective tumor responses were measured and if their paraffin-embedded tumor samples were available. The ERCC1 expression was examined by performing immunohistochemical (IHC) staining, and the patients were divided into two groups (positive or negative) according to the presence of IHC staining of the tumor cell nuclei. RESULTS: Of the 32 eligible patients, 21 patients (66%) had tumor with a positive expression of ERCC1 and the remaining 11 patients had tumor with a negative ERCC1-expression. The ERCC1-negative patients achieved a higher response rate than that of the ERCC1-positive patients (44% vs. 28%, respectively), although the difference was not statistically significant (p=0.42). The median survival time for the all patients was 14.6 months (95% CI: 13.6 to 15.6 months). The one-year survival rate was similar for the ERCC1-negative patients (61%) and the ERCC1-positive patients (70%). CONCLUSION: In the current study, the tumor ERCC1 expression by IHC staining could not predict the clinical response or survival of AGC patients who were treated with cisplatin-based first-line chemotherapy. The ERCC1 protein expression does not appear to be a useful tool for the selection of tailored chemotherapy for these patients.
Cell Nucleus ; Cisplatin ; Deoxycytidine ; Epirubicin ; Fluorouracil ; Humans ; Stomach Neoplasms ; Survival Rate ; Capecitabine

Objectives: The coronavirus disease 2019 (COVID-19) pandemic has continued since its first detection in the Republic of Korea on January 20, 2020. This study describes the early countermeasures used to minimize the risk of COVID-19 outbreaks during cohort quarantine and compares the epidemiological characteristics of 2 outbreaks in long-term care facilities (LTCFs) in Gwangju Metropolitan City in summer 2020. Methods: An epidemiological investigation was conducted via direct visits. We investigated epidemiological characteristics, including incidence, morbidity, and mortality rates, for all residents and staff members. Demographic characteristics were analyzed using a statistical program. Additionally, the method of managing infection in LTCFs is described. Results: Residents and caregivers had high incidence rates in LTCF-A and LTCF-B, respectively. LTCF-B had a longer quarantine period than LTCF-A. The attack rate was 20.02% in LTCF-A and 27.9% in LTCF- B. The mortality rate was 2.3% (1/43) in LTCF-B, the only facility in which a COVID-19 death occurred. Conclusion Extensive management requires contact minimization, which involves testing all contacts to mitigate further transmission in the early stages of LTCF outbreaks. The findings of this study can help inform and prepare public health authorities for COVID-19 outbreaks, particularly for early control in vulnerable facilities.