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Jang TJ, Choi WS, Kim DW, Choi G, Jun H, Ferrari A, Körmann F, Choi PP, Sohn SS. Author Correction: Shear band-driven precipitate dispersion for ultrastrong ductile medium-entropy alloys. Nat Commun 2021; 12:5689. [PMID: 34556669 PMCID: PMC8460621 DOI: 10.1038/s41467-021-26008-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Affiliation(s)
- Tae Jin Jang
- Department of Materials Science and Engineering Korea University, Seoul, South Korea
| | - Won Seok Choi
- Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Dae Woong Kim
- Center for High Entropy Alloys Pohang University of Science and Technology, Pohang, South Korea
| | - Gwanghyo Choi
- Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Hosun Jun
- Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Alberto Ferrari
- Department of Materials Science and Engineering Delft University of Technology, Mekelweg 2, Delft, The Netherlands
| | - Fritz Körmann
- Department of Materials Science and Engineering Delft University of Technology, Mekelweg 2, Delft, The Netherlands.,Max-Planck-Institut für Eisenforschung Max-Planck-Straße 1, Düsseldorf, Germany
| | - Pyuck-Pa Choi
- Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology, Daejeon, South Korea.
| | - Seok Su Sohn
- Department of Materials Science and Engineering Korea University, Seoul, South Korea.
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Jang TJ, Choi WS, Kim DW, Choi G, Jun H, Ferrari A, Körmann F, Choi PP, Sohn SS. Shear band-driven precipitate dispersion for ultrastrong ductile medium-entropy alloys. Nat Commun 2021; 12:4703. [PMID: 34349105 PMCID: PMC8338972 DOI: 10.1038/s41467-021-25031-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 07/13/2021] [Indexed: 11/02/2022] Open
Abstract
Precipitation strengthening has been the basis of physical metallurgy since more than 100 years owing to its excellent strengthening effects. This approach generally employs coherent and nano-sized precipitates, as incoherent precipitates energetically become coarse due to their incompatibility with matrix and provide a negligible strengthening effect or even cause brittleness. Here we propose a shear band-driven dispersion of nano-sized and semicoherent precipitates, which show significant strengthening effects. We add aluminum to a model CoNiV medium-entropy alloy with a face-centered cubic structure to form the L21 Heusler phase with an ordered body-centered cubic structure, as predicted by ab initio calculations. Micro-shear bands act as heterogeneous nucleation sites and generate finely dispersed intragranular precipitates with a semicoherent interface, which leads to a remarkable strength-ductility balance. This work suggests that the structurally dissimilar precipitates, which are generally avoided in conventional alloys, can be a useful design concept in developing high-strength ductile structural materials.
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Affiliation(s)
- Tae Jin Jang
- Department of Materials Science and Engineering Korea University, Seoul, South Korea
| | - Won Seok Choi
- Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Dae Woong Kim
- Center for High Entropy Alloys Pohang University of Science and Technology, Pohang, South Korea
| | - Gwanghyo Choi
- Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Hosun Jun
- Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Alberto Ferrari
- Department of Materials Science and Engineering Delft University of Technology, Mekelweg 2, Delft, The Netherlands
| | - Fritz Körmann
- Department of Materials Science and Engineering Delft University of Technology, Mekelweg 2, Delft, The Netherlands.,Max-Planck-Institut für Eisenforschung Max-Planck-Straße 1, Düsseldorf, Germany
| | - Pyuck-Pa Choi
- Department of Materials Science and Engineering Korea Advanced Institute of Science and Technology, Daejeon, South Korea.
| | - Seok Su Sohn
- Department of Materials Science and Engineering Korea University, Seoul, South Korea.
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Jang TJ, Min SK, Bae JD, Jung KH, Lee JI, Kim JR, Ahn WS. Expression of cyclooxygenase 2, microsomal prostaglandin E synthase 1, and EP receptors is increased in rat oesophageal squamous cell dysplasia and Barrett's metaplasia induced by duodenal contents reflux. Gut 2004; 53:27-33. [PMID: 14684572 PMCID: PMC1773937 DOI: 10.1136/gut.53.1.27] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
BACKGROUND AND AIM It is known that bile acids can induce mucosal injury, stimulate cell proliferation, and promote tumorigenesis. A large body of genetic and biochemical evidence indicate that the biosynthetic pathway of prostaglandin E2 (PGE2) may play an important role in human and rodent tumours. Therefore, we examined the expression pattern of cyclooxygenase 1 (COX-1), COX-2, and microsomal prostaglandin E synthase 1 (mPGES-1), as well as EP receptor subtypes in rat oesophageal lesions induced by duodenal contents reflux. METHODS Oesophagoduodenal anastomosis was performed in rats to induce duodenal contents reflux. We examined histological changes and expression of COX-1, COX-2, mPGES-1, and EP receptor subtypes in the oesophagus by immunohistochemistry and reverse transcription-polymerase chain reaction. RESULTS Normal control oesophageal tissues showed COX-1 expression in subepithelial stromal cells, including endothelial cells and muscular cells, and did not reveal expression of COX-2 or mPGES-1. In the case of squamous cell lesions, immunoreactivity of COX-1 was similar to that of normal lesions, and COX-2 was maximally expressed around the vascular papillae of tissues showing dysplasia and surrounding epithelial layer and basal layer. mPGES-1 was highly expressed in stromal cells with COX-2 expression. In the case of Barrett's oesophagus, COX-2 and mPGES-1 were predominantly in subepithelial stromal cells. mRNA levels of COX-2, mPGES-1, EP2, EP3, and EP4 were higher in the experimental groups than in controls. CONCLUSIONS We suggest that the biosynthetic pathway of PGE2 may play an important role in oesophageal squamous cell dysplasia and glandular metaplasia induced by duodenal contents reflux.
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Affiliation(s)
- T J Jang
- Department of Pathology, Dongguk University College of Medicine, Kyongju, Kyongbuk, Korea.
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Jang TJ, Park JH, Cho MY, Kim JR. Chemically induced rat mammary tumor treated with tamoxifen showed decreased expression of cyclin D1, cyclin E, and p21(Cip1). Cancer Lett 2001; 170:109-16. [PMID: 11463487 DOI: 10.1016/s0304-3835(01)00593-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We studied the effects of tamoxifen (TAM) on the growth of 7,12-dimethylbenz(a)anthracene (DMBA)-induced rat mammary tumor and the expression of cyclin D1, cyclin E, p21(Cip1), and estrogen receptors (ER) by performing immunohistochemistry and Western blot analysis. When tumor size reached between 10 and 15mm in the largest dimension, the rats were divided into a DMBA-control group and a DMBA-TAM group. The administration of TAM markedly decreased the tumor development and showed decreased expression of bromodeoxyuridine, cyclin D1, cyclin E, and p21(Cip1) when compared with those of the DMBA-control group; however, a few tumors showed progressive growth in spite of TAM treatment. These tumors had decreased expression of ER. This study suggests that TAM suppresses tumor development through the down-expression of cyclin D1 and cyclin E.
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Affiliation(s)
- T J Jang
- Department of Pathology, Dongguk University College of Medicine, #707, Sukjang-dong, Kyongju, Kyongbuk 780-714, South Korea.
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Jang TJ, Kim DI, Shin YM, Chang HK, Yang CH. p16(INK4a) Promoter hypermethylation of non-tumorous tissue adjacent to gastric cancer is correlated with glandular atrophy and chronic inflammation. Int J Cancer 2001; 93:629-34. [PMID: 11477571 DOI: 10.1002/ijc.1394] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The p16(INK4a) tumor suppressor gene can be inactivated by promoter region hypermethylation in many tumor types including gastric cancers. However, p16(INK4a) promoter hypermethylation in the surrounding non-tumorous tissues of gastric cancers has not been studied in detail. We therefore examined 46 gastric cancers, corresponding adjacent non-tumorous tissue samples and 8 gastric tissue samples of chronic gastritis by performing methylation-specific polymerase chain reaction, and we analyzed p16(INK4a) protein expression using immunohistochemistry and Western blot. p16(INK4a) promoter hypermethylation was observed in 43% of gastric cancers and 59% of adjacent non-tumorous tissues; however, none of the samples retrieved from the chronic gastritis patients displayed p16(INK4a) promoter hypermethylation. Gastric cancers showed an inverse correlation between vascular invasion and p16(INK4a) promoter hypermethylation, and adjacent non-tumorous tissues displayed a close association among the grade of chronic inflammation, presence of glandular atrophy and p16(INK4a) promoter hypermethylation. p16(INK4a) expression was markedly decreased in samples with p16(INK4a) promoter hypermethylation when compared with samples without p16(INK4a) promoter hypermethylation. These results suggest that p16(INK4a) promoter hypermethylation is an early and frequent event in gastric carcinogenesis and may serve as a new prognostic biomarker for the risk of gastric cancers.
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Affiliation(s)
- T J Jang
- Department of Pathology, Dongguk University College of Medicine, Kyongju, Kyongbuk, Korea.
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Jang TJ, Kang MS, Kim H, Kim DH, Lee JI, Kim JR. Increased expression of cyclin D1, cyclin E and p21(Cip1) associated with decreased expression of p27(Kip1) in chemically induced rat mammary carcinogenesis. Jpn J Cancer Res 2000; 91:1222-32. [PMID: 11123420 PMCID: PMC5926312 DOI: 10.1111/j.1349-7006.2000.tb00908.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
We induced rat mammary tumors in 7-week-old female Sprague-Dawley rats by intragastric administration of 7,12-dimethylbenz(a)anthracene (DMBA), and analyzed by immunohistochemistry the expression of cyclin D1, cyclin E, p21(Cip1), and p27(Kip1) in carcinomas, atypical tumors, and benign tumors as well as normal mammary glands from the control group. Proliferation status was assessed by immunohistochemistry using bromodeoxyuridine (BrdU). A sequential increase in cyclin D1-, cyclin E-, and p21(Cip1)-positive epithelial cells was observed from normal mammary glands, to atypical tumors, to carcinomas. In contrast, carcinomas showed a significantly lower number of epithelial cells immunoreactive to p27(Kip1) when compared with atypical tumors, benign tumors and normal mammary glands. The immunoreactivities of BrdU, cyclin D1, cyclin E, and p21(Cip1) were positively correlated, whereas that of p27(Kip1) appeared inversely correlated to those of the others. Reverse transcriptase-polymerase chain reaction (RT-PCR) and western blot analysis were also performed to determine the mRNA and protein levels of cyclins and cyclin-dependent kinase inhibitors in tumors and normal mammary glands. The protein levels for cyclin D1, cyclin E and p21(Cip1) in carcinomas and atypical tumors were significantly higher than those in benign tumors, while normal mammary glands showed negligible expression. On RT-PCR, tumors showed higher mRNA levels of cyclin D1 and cyclin E than those of normal mammary glands. Our results suggest that rat mammary carcinogenesis involves increased expression of cyclin D1, cyclin E, and p21(Cip1), associated with decreased expression of p27(Kip1).
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Affiliation(s)
- T J Jang
- Department of Pathology, Dongguk University College of Medicine, Sukjang-dong, Kyongju, Kyongbuk 780-714, Korea.
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Abstract
Spontaneous regression of cancer is a rare phenomenon seldom described in patients with hepatocellular carcinoma. A 54-year-old Korean woman suffered from cytologically-proved advanced hepatocellular carcinoma, for which she received no treatment. Papanicolaou's smears revealed high cellularity. Many clusters of polygonal cells showed long, thick anastomosing cords covered by flattened endothelial cells. The polygonal cells showed small hepatocytoid appearance, characterized by increased nuclear/cytoplasmic ratio. She remained in good clinical condition and, at 4 years of follow-up, the hepatocellular carcinoma could not be visualized radiologically. To date, only 14 case reports of apparently spontaneous regression of hepatocellular carcinoma have been published in the English literature. The mechanisms underlying this intriguing phenomenon remain unknown.
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Affiliation(s)
- T J Jang
- Department of Pathology and Radiology, Dongguk University, College of Medicine, Kyongju, Kyongbuk, Korea
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Abstract
We measured cell proliferation and apoptosis in the antral epithelial cells of Helicobacter pylori-infected and H. pylori-uninfected persons, and examined these processes in relation to diagnosis and the histologic parameters of inflammation to investigate their role in cellular turnover in diseases of the upper gastrointestinal tract. The subjects were: 25 patients with antral gastric cancers, 20 with antral gastric ulcers, 18 with duodenal ulcers, and 28 with chronic gastritis, and 4 subjects with normal gastric mucosa. Seventy-two subjects were infected with H. pylori, and 23 subjects, including the 4 with normal gastric mucosa, were uninfected. H. pylori infection was associated with increased apoptosis and cell proliferation in the gastric mucosa, which correlated with the degree of acute inflammation and the density of H. pylori, and these latter two factors correlated with each other. Intestinal metaplasia and glandular atrophy were significantly higher in gastric cancers and gastric ulcers than in duodenal ulcers. Cell proliferation was significantly lower in gastric cancers than in gastric ulcers, but the apoptotic count did not show a significant difference between these diseases. This decreased proliferation in the adjacent mucosa in gastric cancers compared with findings in the other diseases is thought to be closely related to the relatively decreased acute inflammation, which may, partly, contribute to glandular atrophy in the adjacent mucosa of gastric cancer.
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Affiliation(s)
- T J Jang
- Department of Pathology, Dongguk University, College of Medicine, Kyungju, Kyungbuck, Korea
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Abstract
The aim of this study was to examine whether Helicobacter pylori (H. pylori) attaches to areas of intestinal metaplasia in Korean patients. Gastric biopsy specimens with intestinal metaplasia from 8 gastric cancers, 24 gastric ulcers, 11 duodenal ulcers, and 57 chronic gastritis were examined. The specimens were stained with periodic acid-Schiff/alcian blue pH 2.5 and high-iron diamine/alcian blue pH 2.5 to identify the subtype of intestinal metaplasia, and then immunohistochemical stain was done with rabbit anti-H. pylori polyclonal antibody. In 17 patients, H. pylori attached to areas of type II intestinal metaplasia. All areas of intestinal metaplasia showing adherence contained sialomucin, and H. pylori was not detected in the areas of intestinal absorptive cells and sulfomucin-containing metaplastic cells.
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Affiliation(s)
- T J Jang
- Department of Pathology, Dongguk University College of Medicine, Kyongju, Korea.
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Abstract
Heat shock protein (HSP) is thought to play important roles in the cell cycle and various process of carcinogenesis. This study was performed to evaluate the expression of heat shock protein (HSP70) and estrogen receptor (ER) and Ki-67 and to assess relationship between them in cervical squamous cell neoplasia. The materials were 50 cervical squamous cell lesions, consisted of 30 cervical intraepithelial neoplasia (CIN) (6 moderate dysplasia, 11 severe dysplasia, 13 carcinoma in situ), and 20 invasive squamous cell carcinoma (ISCC) cases. These specimens were immunohistochemically stained for HSP70, ER and Ki-67. The score of HSP70 was significantly higher in ISCC than CIN. Expression rate of the ER was not significantly higher in CIN than in ISCC. Ki-67 labelling index was significantly higher in the ISCC and high HSP70 positive staining group. These results suggested that HSP70 may play an important role in tumor cell proliferation and is related with ISCC than CIN, but ER may be not related with tumor cell proliferation and differentiation. HSP70 may be a useful prognostic factor in cervical dysplasia and cancer.
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Affiliation(s)
- K K Kim
- Department of Pathology, Dongguk University, College of Medicine, Kyungju, Korea
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Jang TJ, Lee JI, Kim JR, Kim DH, Bae SH. Decreased gastric proliferation of foveolar epithelial cells after the eradication of Helicobacter pylori. J Korean Med Sci 1997; 12:421-6. [PMID: 9364300 PMCID: PMC3054309 DOI: 10.3346/jkms.1997.12.5.421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Increased epithelial cell proliferation is associated with an increased risk of gastric carcinoma. Helicobacter pylori infection is an established risk factor for gastric cancer and the organism has recently been classified as a group I carcinogen by an IARC working group. In this study, we describe differences in gastric epithelial cell proliferation between a H. pylori eradicated group (n = 21) and a not eradicated group (n = 8) after anti-H. pylori eradication therapy to show that increased cell proliferation is associated with H. pylori infection. H. pylori infection was determined by rapid urease test and immunohistochemical method with anti-H. pylori polyclonal antibody. Gastric epithelial cell proliferation was assessed using immunohistochemical method using Ki-67 monoclonal antibody. Ki-67 positive cells in H. pylori associated chronic active gastritis were observed in the glandular neck and the upper portion of foveolar epithelium. Patients who cleared their H. pylori infections showed a significant decrease of Ki-67 labeling index after therapy (0.73 +/- 0.10 vs. 0.48 +/- 0.08, p < 0.01). By contrast, Ki-67 labeling index before and after treatment in patients who remained positive for H. pylori showed no significant difference (0.78 +/- 0.08 vs 0.74 +/- 0.10, p > 0.05). These results indicate that H. pylori infection increases the proliferation of gastric foveolar epithelium, which is reduced by the eradication therapy. We suggest that anti-H. pylori eradication therapy can prevent mucosal cell proliferation to be closely associated with gastric carcinogenesis.
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Affiliation(s)
- T J Jang
- Department of Pathology, DongGuk University, College of Medicine, Kyungju, Korea
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