Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2002
Using cross-sectional transmission electron microscopy ͑TEM͒, microstructural changes in Ni conta... more Using cross-sectional transmission electron microscopy ͑TEM͒, microstructural changes in Ni contacts on n-type 4H-SiC as a function of annealing temperature were investigated. From these results, the correlation between the microstructural change and electrical properties was interpreted. After annealing at 800°C, which yielded rectifying behavior, the silicide phases were formed, composed of Ni 2 Si and Ni 31 Si 12. From the results shown in microbeam diffraction patterns, Ni 31 Si 12 remains at the surface and Ni 2 Si is dominant in the contact, indicating that Ni 2 Si started to grow at the interface through the outdiffusion of Si atoms. When the sample was annealed at 950°C, ohmic behavior was shown, and the layer structure was changed to a C-rich layer/Ni 2 Si/NiSi/n-type SiC. The NiSi phase was observed. These results imply that the composition of Si in nickel silicide at the interface with SiC increased with the increase of annealing temperature. The observation of the graphite phase at the surface indicates that the C atoms diffused out to the surface at 950°C. This leads to the formation of carbon vacancies, acting as donors for electrons. These suggest that the production of carbon vacancies plays a major role in the formation of ohmic contact through the reduction of the effective Schottky barrier height for the transport of electrons.
Phorbol esters such as phorbol 12-myristate 13-acetate (PMA) have been reported to modulate diver... more Phorbol esters such as phorbol 12-myristate 13-acetate (PMA) have been reported to modulate diverse cellular responses through signal transduction pathways including the protein kinase C (PKC) pathway. In the present study, we sought to determine the effect of PMA on mucin gene expression and on the biological properties of a human colon cancer cell line, HM3. The cells were treated for 8 and 24 h with various concentrations of PMA and total RNA was extracted and Northern and slot blot analyses were carried out using MUC2, MUC3 and MUC5AC mucin cDNA probes to assess the steady state levels of mRNA. Spent media were collected and the level of cancer associated carbohydrate antigens (T, Tn, sialyl Tn, sialyl Lex, and sialyl Lea) and matrix-degrading metalloproteinase (MMPs) activity were examined. Trypsinized cells were used for assessing in vitro invasion, motility and adhesion to matrigel. Our results showed that PMA caused upregulation of steady state mRNA levels of MUC2, MUC3 and MUC5AC which was inhibited after treatment with protein synthesis inhibitors. Calphostin C, a highly specific inhibitor of protein kinase C significantly inhibited the PMA induced induction of mRNA levels of MUC2, MUC3, and MUC5AC. The levels of all cancer-associated mucin carbohydrate antigens examined in the media were increased by PMA treatment. PMA also caused an increase in MMPs activity and in in vitro invasion and motility properties, but did not affect adhesion of HM3 cells to matrigel. Thus, PMA caused a significant increase in the expression of all three mucin genes through signaling pathways involving protein kinase C and increased secretion of mucin associated carbohydrate antigens. These changes were associated with increases in MMP activity as well as by increases in the invasive and motility properties of HM3 colon cancer cells. These data suggest that protein kinase C signaling pathways may be involved in mucin gene regulation and in modulating the invasive and metastatic properties of colon cancer cells.
Asian-Australasian Journal of Animal Sciences, 2009
The present study identified the favorable conditions for isolation, enrichment and in vitro cult... more The present study identified the favorable conditions for isolation, enrichment and in vitro culture of highly purified, undifferentiated pig spermatogonial stem cell (SSC) lines that proliferate for long periods of time in culture. The colonies displayed morphology similar to miceSSC and were positive for markers of SSC (PGP9.5), proliferating germ cell (PigVASA), pre-meiotic germ cell (DAZL) and pluripotency (OCT4, SSEA-1, NANOG, and SOX2) based on immuno-cytochemistry and RT-PCR. The purity of these colonies was confirmed by negative expression of markers for sertoli cell (GATA4 and SOX9), peritubular myoid cell (α-SMA), differentiating spermatogonial and germ cells (c-KIT). The colonies could be maintained with undifferentiated morphology for more than two months and passaged more than 8 times with doubling time between 6-7 days. Taken together, we conclude that pigSSC could be successfully isolated and cultured in vitro and they possess characteristics similar to miceSSC.
Rutin was isolated from dried leaves and flowers of buckwheat (Fagopyrum esculentum Moench.). The... more Rutin was isolated from dried leaves and flowers of buckwheat (Fagopyrum esculentum Moench.). The effects of rutin on angiotensin II-induced hypertrophy of cultured cardiac myocytes and proliferation of cardiac fibroblasts of neonatal rats were evaluated by analyzing the cell surface area, measuring the protein synthesis rate through 3 H-leucine incorporation, and the MTT method. Rutin (0.8 to 8.0 mg/l) exhibited a strong inhibition on the hypertrophy and proliferation. The results suggested that rutin from buckwheat flowers and leaves might have protective effects on cardiac hypertrophy.
Advances in Experimental Medicine and Biology, 2009
Introduction The family of class B G-protein coupled receptors (GPCRs) includes cognate receptors... more Introduction The family of class B G-protein coupled receptors (GPCRs) includes cognate receptors for peptide hormones like secretin, glucagon, glucagon-like peptide-1 (GLP-1), vasoactive intestinal peptide (VIP), parathyroid hormone (PTH), pituitary adenylate cyclase activating peptide ( ...
ABSTRACT The Si Mini-Pad sensor is an essential component of the MPC-EX preshower detector. This ... more ABSTRACT The Si Mini-Pad sensor is an essential component of the MPC-EX preshower detector. This detector will be integrated into the PHENIX experiment at Brookhaven National Laboratory's Relativistic Heavy Ion Collider. We describe the development of the surface pattern and the fabrication process of the Si Mini-Pad sensor and present a test by the low energy gamma irradiation that is sensitive to the surface design.
For the first time, a single crystalline FeTiO 3 nanodisc in the ilmenite phase has been synthesi... more For the first time, a single crystalline FeTiO 3 nanodisc in the ilmenite phase has been synthesized by a hydrothermal reaction at 220°C. The prepared FeTiO 3 was a hexagonal disk-like structure with an average diameter of ∼400 nm and a thickness of ∼70 nm, while its hexagonal face was oriented in (001) plane and grown to (110) direction. The heterojunction structure was formed between the as-prepared FeTiO 3 nanodisc and Degussa P25 with an average particle size of ∼25 nm by employing maleic acid as an organic linker. The prepared FeTiO 3 /TiO 2 coupled at a nanoscale demonstrated greatly enhanced photocatalytic activity in removing 2-propanol and evolving CO 2 in gas phase under visible light irradiation (λ g 420 nm). Its degradation constant (k) in removing 2-propanol was ∼25 times that of Degussa P25, which suggests that its catalytic efficiency is comparable to that of a typical N-doped TiO 2. The remarkable photocatalytic activity of FeTiO 3 / TiO 2 could be explained by the intersemiconductor hole-transfer mechanism caused by the unique relative band positions of these two semiconductors.
Proceedings of the National Academy of Sciences, 2003
Inactivation of the tumor suppressor p53 by missense mutations is the most frequent genetic alter... more Inactivation of the tumor suppressor p53 by missense mutations is the most frequent genetic alteration in human cancers. The common missense mutations in the TP53 gene disrupt the ability of p53 to bind to DNA and consequently to transactivate downstream genes. However, it is still not fully understood how a large number of the remaining mutations affect p53 structure and function. Here, we used a comprehensive site-directed mutagenesis technique and a yeast-based functional assay to construct, express, and evaluate 2,314 p53 mutants representing all possible amino acid substitutions caused by a point mutation throughout the protein (5.9 substitutions per residue), and correlated p53 function with structure- and tumor-derived mutations. This high-resolution mutation analysis allows evaluation of previous predictions and hypotheses through interrelation of function, structure and mutation.
Background. High glucose and angiotensin-II (Ang-II) levels are the known important mediators of ... more Background. High glucose and angiotensin-II (Ang-II) levels are the known important mediators of diabetic nephropathy. However, the effects of these mediators on matrix metalloproteinase-2 (MMP-2) and on tissue inhibitor of metalloproteinase-2 (TIMP-2) in proximal tubule cells have yet to be fully examined within the context of early stage diabetic nephropathy. Methods. In this study, we attempted to characterize changes in MMP-2 and TIMP-2 in streptozotocininduced diabetic rats. To further examine the molecular mechanisms involved, we evaluated the effects of high glucose (30 mM) or Ang-II on MMP-2, TIMP-2 and collagen synthesis in proximal tubule cells, and investigated whether MMP-2 and TIMP-2 are regulated via the TGF-b1 pathway. Results. In streptozotocin-induced diabetic rats, TIMP-2 mRNA and protein levels were significantly higher than in controls. Urinary protein excretion also showed a significant positive correlation with glomerular and tubular TIMP-2 protein expressions, and a negative correlation with MMP-2 expression. In cultured cells, both high glucose and Ang-II induced significant increases in TGF-b1, TIMP-2, and in collagen synthesis, and significant decreases in MMP-2 gene expression and activity, and thus disrupted the balance between MMP-2 and TIMP-2. Moreover, treatment with a selective angiotensin type 1 (AT1) receptor antagonist significantly inhibited Ang-II mediated changes in TGF-b1, MMP-2, TIMP-2, and in collagen production, suggesting the role of the AT1 receptor. The addition of exogenous TGF-b1 produced an effect similar to those of high glucose and Ang-II. Furthermore, the inhibition of TGF-b1 protein prevented Ang-II-induced MMP-2 and TIMP-2 alterations, suggesting the involvement of a TGF-b1 pathway. Conclusions. High glucose or Ang-II treatment induce alterations in MMP-2 and TIMP-2 balance, which favour TIMP-2 over-activity. Moreover, Ang-IImediated changes in the productions of MMP-2 and TIMP-2 occur via AT1 receptors and a TGF-b1dependent mechanism. These results suggest that an imbalance between the MMP-2 and TIMP-2, caused primarily by an increase in TIMP-2 activity, contributes to the pathogenesis of diabetic nephropathy.
... E-mail The Corresponding Author , b , Cheol-Ju Kim E-mail The Corresponding Author , b , Tae-... more ... E-mail The Corresponding Author , b , Cheol-Ju Kim E-mail The Corresponding Author , b , Tae-Won Park E-mail The Corresponding Author , c and Yeong-Deug Jeong ... GAIM has many advantages such as reduction of material, sink mark, warpage, and lower injection pressure. ...
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2002
Using cross-sectional transmission electron microscopy ͑TEM͒, microstructural changes in Ni conta... more Using cross-sectional transmission electron microscopy ͑TEM͒, microstructural changes in Ni contacts on n-type 4H-SiC as a function of annealing temperature were investigated. From these results, the correlation between the microstructural change and electrical properties was interpreted. After annealing at 800°C, which yielded rectifying behavior, the silicide phases were formed, composed of Ni 2 Si and Ni 31 Si 12. From the results shown in microbeam diffraction patterns, Ni 31 Si 12 remains at the surface and Ni 2 Si is dominant in the contact, indicating that Ni 2 Si started to grow at the interface through the outdiffusion of Si atoms. When the sample was annealed at 950°C, ohmic behavior was shown, and the layer structure was changed to a C-rich layer/Ni 2 Si/NiSi/n-type SiC. The NiSi phase was observed. These results imply that the composition of Si in nickel silicide at the interface with SiC increased with the increase of annealing temperature. The observation of the graphite phase at the surface indicates that the C atoms diffused out to the surface at 950°C. This leads to the formation of carbon vacancies, acting as donors for electrons. These suggest that the production of carbon vacancies plays a major role in the formation of ohmic contact through the reduction of the effective Schottky barrier height for the transport of electrons.
Phorbol esters such as phorbol 12-myristate 13-acetate (PMA) have been reported to modulate diver... more Phorbol esters such as phorbol 12-myristate 13-acetate (PMA) have been reported to modulate diverse cellular responses through signal transduction pathways including the protein kinase C (PKC) pathway. In the present study, we sought to determine the effect of PMA on mucin gene expression and on the biological properties of a human colon cancer cell line, HM3. The cells were treated for 8 and 24 h with various concentrations of PMA and total RNA was extracted and Northern and slot blot analyses were carried out using MUC2, MUC3 and MUC5AC mucin cDNA probes to assess the steady state levels of mRNA. Spent media were collected and the level of cancer associated carbohydrate antigens (T, Tn, sialyl Tn, sialyl Lex, and sialyl Lea) and matrix-degrading metalloproteinase (MMPs) activity were examined. Trypsinized cells were used for assessing in vitro invasion, motility and adhesion to matrigel. Our results showed that PMA caused upregulation of steady state mRNA levels of MUC2, MUC3 and MUC5AC which was inhibited after treatment with protein synthesis inhibitors. Calphostin C, a highly specific inhibitor of protein kinase C significantly inhibited the PMA induced induction of mRNA levels of MUC2, MUC3, and MUC5AC. The levels of all cancer-associated mucin carbohydrate antigens examined in the media were increased by PMA treatment. PMA also caused an increase in MMPs activity and in in vitro invasion and motility properties, but did not affect adhesion of HM3 cells to matrigel. Thus, PMA caused a significant increase in the expression of all three mucin genes through signaling pathways involving protein kinase C and increased secretion of mucin associated carbohydrate antigens. These changes were associated with increases in MMP activity as well as by increases in the invasive and motility properties of HM3 colon cancer cells. These data suggest that protein kinase C signaling pathways may be involved in mucin gene regulation and in modulating the invasive and metastatic properties of colon cancer cells.
症例は66歳，男性．上腹部痛，タール便を主訴に入院となった．上部消化管内視鏡検査にて十二指腸球後部に出血を伴う潰瘍を認め，クリッピングによる止血術を施行した．腹部超音波検査にて膵頭部に低エコー域... more 症例は66歳，男性．上腹部痛，タール便を主訴に入院となった．上部消化管内視鏡検査にて十二指腸球後部に出血を伴う潰瘍を認め，クリッピングによる止血術を施行した．腹部超音波検査にて膵頭部に低エコー域を認め，カラードップラーエコーにて低吸収域内にモザイクサインがみられた．腹部CT検査では膵頭部に低吸収域と高吸収域の混在する不整形な腫瘤像を認め，腹部血管造影検査では網目状の血管網がみられた．膵動静脈奇形と診断，再び上腹部不快感とタール便を認めた為，緊急手術を行った．幽門輪温存膵頭十二指腸切除術を施行，術後経過は良好であった．病理検査では膵頭部に拡張し蛇行した大小の動静脈を多数認め，十二指腸壁を破壊し潰瘍底に達していた．十二指腸潰瘍を契機に発症した膵動静脈奇形は稀であり，若干の文献的考察を加え報告する．
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2002
Using cross-sectional transmission electron microscopy ͑TEM͒, microstructural changes in Ni conta... more Using cross-sectional transmission electron microscopy ͑TEM͒, microstructural changes in Ni contacts on n-type 4H-SiC as a function of annealing temperature were investigated. From these results, the correlation between the microstructural change and electrical properties was interpreted. After annealing at 800°C, which yielded rectifying behavior, the silicide phases were formed, composed of Ni 2 Si and Ni 31 Si 12. From the results shown in microbeam diffraction patterns, Ni 31 Si 12 remains at the surface and Ni 2 Si is dominant in the contact, indicating that Ni 2 Si started to grow at the interface through the outdiffusion of Si atoms. When the sample was annealed at 950°C, ohmic behavior was shown, and the layer structure was changed to a C-rich layer/Ni 2 Si/NiSi/n-type SiC. The NiSi phase was observed. These results imply that the composition of Si in nickel silicide at the interface with SiC increased with the increase of annealing temperature. The observation of the graphite phase at the surface indicates that the C atoms diffused out to the surface at 950°C. This leads to the formation of carbon vacancies, acting as donors for electrons. These suggest that the production of carbon vacancies plays a major role in the formation of ohmic contact through the reduction of the effective Schottky barrier height for the transport of electrons.
Phorbol esters such as phorbol 12-myristate 13-acetate (PMA) have been reported to modulate diver... more Phorbol esters such as phorbol 12-myristate 13-acetate (PMA) have been reported to modulate diverse cellular responses through signal transduction pathways including the protein kinase C (PKC) pathway. In the present study, we sought to determine the effect of PMA on mucin gene expression and on the biological properties of a human colon cancer cell line, HM3. The cells were treated for 8 and 24 h with various concentrations of PMA and total RNA was extracted and Northern and slot blot analyses were carried out using MUC2, MUC3 and MUC5AC mucin cDNA probes to assess the steady state levels of mRNA. Spent media were collected and the level of cancer associated carbohydrate antigens (T, Tn, sialyl Tn, sialyl Lex, and sialyl Lea) and matrix-degrading metalloproteinase (MMPs) activity were examined. Trypsinized cells were used for assessing in vitro invasion, motility and adhesion to matrigel. Our results showed that PMA caused upregulation of steady state mRNA levels of MUC2, MUC3 and MUC5AC which was inhibited after treatment with protein synthesis inhibitors. Calphostin C, a highly specific inhibitor of protein kinase C significantly inhibited the PMA induced induction of mRNA levels of MUC2, MUC3, and MUC5AC. The levels of all cancer-associated mucin carbohydrate antigens examined in the media were increased by PMA treatment. PMA also caused an increase in MMPs activity and in in vitro invasion and motility properties, but did not affect adhesion of HM3 cells to matrigel. Thus, PMA caused a significant increase in the expression of all three mucin genes through signaling pathways involving protein kinase C and increased secretion of mucin associated carbohydrate antigens. These changes were associated with increases in MMP activity as well as by increases in the invasive and motility properties of HM3 colon cancer cells. These data suggest that protein kinase C signaling pathways may be involved in mucin gene regulation and in modulating the invasive and metastatic properties of colon cancer cells.
Asian-Australasian Journal of Animal Sciences, 2009
The present study identified the favorable conditions for isolation, enrichment and in vitro cult... more The present study identified the favorable conditions for isolation, enrichment and in vitro culture of highly purified, undifferentiated pig spermatogonial stem cell (SSC) lines that proliferate for long periods of time in culture. The colonies displayed morphology similar to miceSSC and were positive for markers of SSC (PGP9.5), proliferating germ cell (PigVASA), pre-meiotic germ cell (DAZL) and pluripotency (OCT4, SSEA-1, NANOG, and SOX2) based on immuno-cytochemistry and RT-PCR. The purity of these colonies was confirmed by negative expression of markers for sertoli cell (GATA4 and SOX9), peritubular myoid cell (α-SMA), differentiating spermatogonial and germ cells (c-KIT). The colonies could be maintained with undifferentiated morphology for more than two months and passaged more than 8 times with doubling time between 6-7 days. Taken together, we conclude that pigSSC could be successfully isolated and cultured in vitro and they possess characteristics similar to miceSSC.
Rutin was isolated from dried leaves and flowers of buckwheat (Fagopyrum esculentum Moench.). The... more Rutin was isolated from dried leaves and flowers of buckwheat (Fagopyrum esculentum Moench.). The effects of rutin on angiotensin II-induced hypertrophy of cultured cardiac myocytes and proliferation of cardiac fibroblasts of neonatal rats were evaluated by analyzing the cell surface area, measuring the protein synthesis rate through 3 H-leucine incorporation, and the MTT method. Rutin (0.8 to 8.0 mg/l) exhibited a strong inhibition on the hypertrophy and proliferation. The results suggested that rutin from buckwheat flowers and leaves might have protective effects on cardiac hypertrophy.
Advances in Experimental Medicine and Biology, 2009
Introduction The family of class B G-protein coupled receptors (GPCRs) includes cognate receptors... more Introduction The family of class B G-protein coupled receptors (GPCRs) includes cognate receptors for peptide hormones like secretin, glucagon, glucagon-like peptide-1 (GLP-1), vasoactive intestinal peptide (VIP), parathyroid hormone (PTH), pituitary adenylate cyclase activating peptide ( ...
ABSTRACT The Si Mini-Pad sensor is an essential component of the MPC-EX preshower detector. This ... more ABSTRACT The Si Mini-Pad sensor is an essential component of the MPC-EX preshower detector. This detector will be integrated into the PHENIX experiment at Brookhaven National Laboratory's Relativistic Heavy Ion Collider. We describe the development of the surface pattern and the fabrication process of the Si Mini-Pad sensor and present a test by the low energy gamma irradiation that is sensitive to the surface design.
For the first time, a single crystalline FeTiO 3 nanodisc in the ilmenite phase has been synthesi... more For the first time, a single crystalline FeTiO 3 nanodisc in the ilmenite phase has been synthesized by a hydrothermal reaction at 220°C. The prepared FeTiO 3 was a hexagonal disk-like structure with an average diameter of ∼400 nm and a thickness of ∼70 nm, while its hexagonal face was oriented in (001) plane and grown to (110) direction. The heterojunction structure was formed between the as-prepared FeTiO 3 nanodisc and Degussa P25 with an average particle size of ∼25 nm by employing maleic acid as an organic linker. The prepared FeTiO 3 /TiO 2 coupled at a nanoscale demonstrated greatly enhanced photocatalytic activity in removing 2-propanol and evolving CO 2 in gas phase under visible light irradiation (λ g 420 nm). Its degradation constant (k) in removing 2-propanol was ∼25 times that of Degussa P25, which suggests that its catalytic efficiency is comparable to that of a typical N-doped TiO 2. The remarkable photocatalytic activity of FeTiO 3 / TiO 2 could be explained by the intersemiconductor hole-transfer mechanism caused by the unique relative band positions of these two semiconductors.
Proceedings of the National Academy of Sciences, 2003
Inactivation of the tumor suppressor p53 by missense mutations is the most frequent genetic alter... more Inactivation of the tumor suppressor p53 by missense mutations is the most frequent genetic alteration in human cancers. The common missense mutations in the TP53 gene disrupt the ability of p53 to bind to DNA and consequently to transactivate downstream genes. However, it is still not fully understood how a large number of the remaining mutations affect p53 structure and function. Here, we used a comprehensive site-directed mutagenesis technique and a yeast-based functional assay to construct, express, and evaluate 2,314 p53 mutants representing all possible amino acid substitutions caused by a point mutation throughout the protein (5.9 substitutions per residue), and correlated p53 function with structure- and tumor-derived mutations. This high-resolution mutation analysis allows evaluation of previous predictions and hypotheses through interrelation of function, structure and mutation.
Background. High glucose and angiotensin-II (Ang-II) levels are the known important mediators of ... more Background. High glucose and angiotensin-II (Ang-II) levels are the known important mediators of diabetic nephropathy. However, the effects of these mediators on matrix metalloproteinase-2 (MMP-2) and on tissue inhibitor of metalloproteinase-2 (TIMP-2) in proximal tubule cells have yet to be fully examined within the context of early stage diabetic nephropathy. Methods. In this study, we attempted to characterize changes in MMP-2 and TIMP-2 in streptozotocininduced diabetic rats. To further examine the molecular mechanisms involved, we evaluated the effects of high glucose (30 mM) or Ang-II on MMP-2, TIMP-2 and collagen synthesis in proximal tubule cells, and investigated whether MMP-2 and TIMP-2 are regulated via the TGF-b1 pathway. Results. In streptozotocin-induced diabetic rats, TIMP-2 mRNA and protein levels were significantly higher than in controls. Urinary protein excretion also showed a significant positive correlation with glomerular and tubular TIMP-2 protein expressions, and a negative correlation with MMP-2 expression. In cultured cells, both high glucose and Ang-II induced significant increases in TGF-b1, TIMP-2, and in collagen synthesis, and significant decreases in MMP-2 gene expression and activity, and thus disrupted the balance between MMP-2 and TIMP-2. Moreover, treatment with a selective angiotensin type 1 (AT1) receptor antagonist significantly inhibited Ang-II mediated changes in TGF-b1, MMP-2, TIMP-2, and in collagen production, suggesting the role of the AT1 receptor. The addition of exogenous TGF-b1 produced an effect similar to those of high glucose and Ang-II. Furthermore, the inhibition of TGF-b1 protein prevented Ang-II-induced MMP-2 and TIMP-2 alterations, suggesting the involvement of a TGF-b1 pathway. Conclusions. High glucose or Ang-II treatment induce alterations in MMP-2 and TIMP-2 balance, which favour TIMP-2 over-activity. Moreover, Ang-IImediated changes in the productions of MMP-2 and TIMP-2 occur via AT1 receptors and a TGF-b1dependent mechanism. These results suggest that an imbalance between the MMP-2 and TIMP-2, caused primarily by an increase in TIMP-2 activity, contributes to the pathogenesis of diabetic nephropathy.
... E-mail The Corresponding Author , b , Cheol-Ju Kim E-mail The Corresponding Author , b , Tae-... more ... E-mail The Corresponding Author , b , Cheol-Ju Kim E-mail The Corresponding Author , b , Tae-Won Park E-mail The Corresponding Author , c and Yeong-Deug Jeong ... GAIM has many advantages such as reduction of material, sink mark, warpage, and lower injection pressure. ...
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2002
Using cross-sectional transmission electron microscopy ͑TEM͒, microstructural changes in Ni conta... more Using cross-sectional transmission electron microscopy ͑TEM͒, microstructural changes in Ni contacts on n-type 4H-SiC as a function of annealing temperature were investigated. From these results, the correlation between the microstructural change and electrical properties was interpreted. After annealing at 800°C, which yielded rectifying behavior, the silicide phases were formed, composed of Ni 2 Si and Ni 31 Si 12. From the results shown in microbeam diffraction patterns, Ni 31 Si 12 remains at the surface and Ni 2 Si is dominant in the contact, indicating that Ni 2 Si started to grow at the interface through the outdiffusion of Si atoms. When the sample was annealed at 950°C, ohmic behavior was shown, and the layer structure was changed to a C-rich layer/Ni 2 Si/NiSi/n-type SiC. The NiSi phase was observed. These results imply that the composition of Si in nickel silicide at the interface with SiC increased with the increase of annealing temperature. The observation of the graphite phase at the surface indicates that the C atoms diffused out to the surface at 950°C. This leads to the formation of carbon vacancies, acting as donors for electrons. These suggest that the production of carbon vacancies plays a major role in the formation of ohmic contact through the reduction of the effective Schottky barrier height for the transport of electrons.
Phorbol esters such as phorbol 12-myristate 13-acetate (PMA) have been reported to modulate diver... more Phorbol esters such as phorbol 12-myristate 13-acetate (PMA) have been reported to modulate diverse cellular responses through signal transduction pathways including the protein kinase C (PKC) pathway. In the present study, we sought to determine the effect of PMA on mucin gene expression and on the biological properties of a human colon cancer cell line, HM3. The cells were treated for 8 and 24 h with various concentrations of PMA and total RNA was extracted and Northern and slot blot analyses were carried out using MUC2, MUC3 and MUC5AC mucin cDNA probes to assess the steady state levels of mRNA. Spent media were collected and the level of cancer associated carbohydrate antigens (T, Tn, sialyl Tn, sialyl Lex, and sialyl Lea) and matrix-degrading metalloproteinase (MMPs) activity were examined. Trypsinized cells were used for assessing in vitro invasion, motility and adhesion to matrigel. Our results showed that PMA caused upregulation of steady state mRNA levels of MUC2, MUC3 and MUC5AC which was inhibited after treatment with protein synthesis inhibitors. Calphostin C, a highly specific inhibitor of protein kinase C significantly inhibited the PMA induced induction of mRNA levels of MUC2, MUC3, and MUC5AC. The levels of all cancer-associated mucin carbohydrate antigens examined in the media were increased by PMA treatment. PMA also caused an increase in MMPs activity and in in vitro invasion and motility properties, but did not affect adhesion of HM3 cells to matrigel. Thus, PMA caused a significant increase in the expression of all three mucin genes through signaling pathways involving protein kinase C and increased secretion of mucin associated carbohydrate antigens. These changes were associated with increases in MMP activity as well as by increases in the invasive and motility properties of HM3 colon cancer cells. These data suggest that protein kinase C signaling pathways may be involved in mucin gene regulation and in modulating the invasive and metastatic properties of colon cancer cells.
症例は66歳，男性．上腹部痛，タール便を主訴に入院となった．上部消化管内視鏡検査にて十二指腸球後部に出血を伴う潰瘍を認め，クリッピングによる止血術を施行した．腹部超音波検査にて膵頭部に低エコー域... more 症例は66歳，男性．上腹部痛，タール便を主訴に入院となった．上部消化管内視鏡検査にて十二指腸球後部に出血を伴う潰瘍を認め，クリッピングによる止血術を施行した．腹部超音波検査にて膵頭部に低エコー域を認め，カラードップラーエコーにて低吸収域内にモザイクサインがみられた．腹部CT検査では膵頭部に低吸収域と高吸収域の混在する不整形な腫瘤像を認め，腹部血管造影検査では網目状の血管網がみられた．膵動静脈奇形と診断，再び上腹部不快感とタール便を認めた為，緊急手術を行った．幽門輪温存膵頭十二指腸切除術を施行，術後経過は良好であった．病理検査では膵頭部に拡張し蛇行した大小の動静脈を多数認め，十二指腸壁を破壊し潰瘍底に達していた．十二指腸潰瘍を契機に発症した膵動静脈奇形は稀であり，若干の文献的考察を加え報告する．
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