The high Curie temperature and long-range ferromagnetism in Mn-doped 3C-SiC: a study using first-principles calculation

Lin Xue-ling,Zhang He-xiang,Yang Wei-xia,Chen Huan-ming,Pan Feng-chun 한국물리학회 2021 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.79 No.6

Magnetic semiconductors with high Curie temper (TC) and inherent ferromagnetism, which not only provide a data-processing function via semiconductors’ properties, but also offer a data-storage function through intrinsic ferromagnetism, have become key materials in the field of spintronics. We studied the electronic structures and magnetic properties of Mn-doped cubic (3C) SiC using first-principles calculation. The calculated results revealed that MnSi and MnC substitutions can introduce 3 μB and 1 μB magnetic moments into SiC, respectively, which are both localized and extended. The extended tails of the moments indicate a significant spatial extension of the spin-polarized electron states. The interaction between the long tails, which can mediate long-range ferromagnetic (FM) coupling up to 8.55 Å, and is very different from common exchange, in which the ferromagnetism decreases sharply with increasing distance between the moments, and is hard to maintain to the next-neighbor order due to the limited spatial spin-electrons distribution. The distributions of magnetic moments become more and more localized or extended as compressive or tensile strains are increased, but FM interactions under compressive and tensile strains are weaker than those in undeformed structure. The FM coupling mechanism is explained and discussed in detail using p–d electron exchange. These results can provide a routine for engineering FM semiconductor of 3C-SiC.

Establishment and Validation of a Nomogram for Nasopharyngeal Carcinoma Patients Concerning the Prognostic Effect of Parotid Lymph Node Metastases

Chao Lin,Xue-Song Sun,Sai-Lan Liu,Xiao-Yun Li,Nian Lu,Xin-Ling Li,Lin-Quan Tang,Ling Guo 대한암학회 2020 Cancer Research and Treatment Vol.52 No.3

Purpose The prognosis of nasopharyngeal carcinoma (NPC) patients with parotid lymph node (PLN) metastasis remains unclear. This study was performed to investigate the prognostic significance and optimal staging category of PLN metastasis and develop a nomogram for estimating individual risk. Materials and Methods Clinical data of 7,084 non-metastatic NPC patients were retrospectively reviewed. Overall survival (OS) was the primary endpoint. A nomogram was established based on the Cox proportional hazards regression model. The accuracy and calibration ability of this nomogram was evaluated by C-index and calibration curves with bootstrap validation. Results Totally, 164/7,084 NPC patients (2.3%) presented with PLNs. Multivariate analyses showed that PLN metastasis was a negative prognostic factor for OS, progression-free survival (PFS), distant metastasis-free survival (DMFS), and locoregional relapse-free survival (LRFS). Patients with PLN metastasis had a worse prognosis than N3 disease. Five independent prognostic factors were included in the nomogram, which showed a C-index of 0.743. The calibration curves for probability of 3- and 5-year OS indicated satisfactory agreement between nomogram-based prediction and actual observation. All results were confirmed in the validation cohort. Conclusion NPC patient with PLN metastasis had poorer survival outcome (OS, PFS, DMFS, and LRFS) than N3 disease. We developed a nomogram to provide individual prediction of OS for patients with PLN metastasis.

Barrier Optical Waveguide Fabrication in LiNbO3 Crystal by 4.5-MeV LithiumIon Implantation with Low Dose

Xue-Lin Wang,Ding-Yu Shen,Gang Fu,Hong-Ji Ma,Ke-Ming Wang,Rui Nie,Shi-Ling Li 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.46 No.1

A barrier planar waveguide was fabricated in z-cut LiNbdO3 crystals by 4.5-MeV lithium ion implantation at a dose of 3 £ 1014 ions/cm2 at room temperature. Dark modes were observed by the prism-coupling method with wavelengths of both 633 nm and 1539 nm. The refractive index pro¯les were reconstructed by using the re°ectivity calculation method. There were about 1.1 % and 0.7 % decreases at the optical barriers of the ordinary and extraordinary refractive index at the wavelength at 633 nm, and the positions of the optical barriers were close to those of the damage peaks calculated by the TRIM098 (Transport of Ions in Matter) code. It is found that the refractive index change may be partly due to the damage induced by nuclear collision.

Theoretical Studies on Electronic Structure and Absorption Spectrum of Prototypical Technetium-Diphosphonate Complex ^(99m)Tc-MDP

Ling Qiu,Jian-Guo Lin,Shi-Neng Luo,Xue-Dong Gong,Xue-Hai Ju 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.7

Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations,employing the B3LYP method and the LANL2DZ, 6-31G^*(LANL2DZ for Tc), 6-31G^*(cc-pVDZ-pp for Tc)and DGDZVP basis sets, have been performed to investigate the electronic structures and absorption spectra of the technetium-99m-labeled methylenediphosphonate (^(99m)Tc-MDP) complex of the simplest diphosphonate ligand. The bonding situations and natural bond orbital compositions were studied by the Mulliken population analysis (MPA) and natural bond orbital (NBO) analysis. The results indicate that the σ and π contributions to the Tc-O bonds are strongly polarized towards the oxygen atoms and the ionic contribution to the Tc-O bonding is larger than the covalent contribution. The electronic transitions investigated by TDDFT calculations and molecular orbital analyses show that the origin of all absorption bands is ascribed to the ligand-to-metal charge transfer (LMCT) character. The solvent effect on the electronic structures and absorption spectra has also been studied by performing DFT and TDDFT calculations at the B3LYP/6-31G^*(cc-pVDZ-pp for Tc) level with the integral equation formalism polarized continuum model (IEFPCM) in different media. It is found that the absorption spectra display blue shift in different extents with the increase of solvent polarity.

Substituent Effect on the Structure and Biological Property of 99mTc-Labeled Diphosphonates: Theoretical Studies

Ling Qiu,Jian-Guo Lin,Xue-Dong Gong,Wen Cheng,Shi-Neng Luo 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.12

Theoretical calculations based on density functional theory (DFT) were performed to study the substituent effect on the geometric and electronic structures as well as the biological behavior of technetium-99m-labeled diphosphonate complexes. Optimized structures of these complexes are surrounded by six ligands in an octahedral environment with three unpaired 4d electrons (d3 state) and the optimized geometry of 99mTc-MDP agrees with experimental data. With the increase of electron-donating substituent or tether between phosphate groups, the energy gap between frontier orbitals increases and the probability of non-radiative deactivation via d-d electron transfer decreases. The charge distribution reflects a significant ligand-to-metal electron donation. Based on the calculated geometric and electronic structures and biologic properties of 99mTc-diphosphonate complexes, several structure-activity relationships (SARs) were established. These results may be instructive for the design and synthesis of novel 99mTc-diphosphonate bone imaging agent and other 99mTc-based radiopharmaceuticals.

Effects of Tissue Factor, PAR-2 and MMP-9 Expression on Human Breast Cancer Cell Line MCF-7 Invasion

Lin, Zeng-Mao,Zhao, Jian-Xin,Duan, Xue-Ning,Zhang, Lan-Bo,Ye, Jing-Ming,Xu, Ling,Liu, Yin-Hua Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.2

Objective: This study aimed to explore the expression of tissue factor (TF), protease activated receptor-2 (PAR-2), and matrix metalloproteinase-9 (MMP-9) in the MCF-7 breast cancer cell line and influence on invasiveness. Methods: Stable MCF-7 cells transfected with TF cDNA and with TF ShRNA were established. TF, PAR-2, and MMP-9 protein expression was analyzed using indirect immunofluorescence and invasiveness was evaluated using a cell invasion test. Effects of an exogenous PAR-2 agonist were also examined. Results: TF protein expression significantly differed between the TF cDNA and TF ShRNA groups. MMP-9 protein expression was significantly correlated with TF protein expression, but PAR-2 protein expression was unaffected. The PAR-2 agonist significantly enhanced MMP-9 expression and slightly increased TF and PAR-2 expression in the TF ShRNA group, but did not significantly affect protein expression in MCF-7 cells transfected with TF cDNA. TF and MMP-9 expression was positively correlated with the invasiveness of tumor cells. Conclusion: TF, PAR-2, and MMP-9 affect invasiveness of MCF-7 cells. TF may increase MMP-9 expression by activating PAR-2.

Expression and Function of GSTA1 in Lung Cancer Cells

Pan, Xue-Diao,Yang, Zhou-Ping,Tang, Qi-Ling,Peng, Tong,Zhang, Zheng-Bing,Zhou, Si-Gui,Wang, Gui-Xiang,He, Bing,Zang, Lin-Quan Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.20

Glutathione S-transferase A1 (GSTA1) appears to be primarily involved in detoxification processes, but possible roles in lung cancer remain unclear. The objective of this study was to investigate the expression and function of GSTA1 in lung cancer cells. Real-time PCR and Western blotting were performed to assess expression in cancer cell lines and the normal lung cells, then verify the A549 cells line with stable overexpression. Localization of GSTA1 proteins was assessed by cytoimmunofluorescence. Three double-strand DNA oligoRNAs (SiRNAs) were synthesized prior to being transfected into A549 cells with Lipofectamine 2000, and then the most efficient SiRNA was selected. Expression of the GSTA1 gene in the transfected cells was determined by real-time PCR and Western blotting. The viability of the transfected cells were assessed by MTT. Results showed that the mRNA and protein expression of A549 cancer cells was higher than in MRC-5 normal cells. Cytoimmunofluorescence demonstrated GSTA1 localization in the cell cytoplasm and/or membranes. Transfection into A549 cells demonstrated that down-regulated expression could inhibit cell viability. Our data indicated that GSTA1 expression may be a target molecule in early diagnosis and treatment of lung cancer.

Theoretical Studies on Electronic Structure and Absorption Spectrum of Prototypical Technetium-Diphosphonate Complex ^99mTc-MDP

Qiu, Ling,Lin, Jian-Guo,Gong, Xue-Dong,Ju, Xue-Hai,Luo, Shi-Neng Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.7

Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations, employing the B3LYP method and the LANL2DZ, 6-31G$^*$(LANL2DZ for Tc), 6-31G$^*$(cc-pVDZ-pp for Tc) and DGDZVP basis sets, have been performed to investigate the electronic structures and absorption spectra of the technetium-99m-labeled methylenediphosphonate ($^{99m}Tc$-MDP) complex of the simplest diphosphonate ligand. The bonding situations and natural bond orbital compositions were studied by the Mulliken population analysis (MPA) and natural bond orbital (NBO) analysis. The results indicate that the ${\sigma}$ and ${\pi}$ contributions to the Tc-O bonds are strongly polarized towards the oxygen atoms and the ionic contribution to the Tc-O bonding is larger than the covalent contribution. The electronic transitions investigated by TDDFT calculations and molecular orbital analyses show that the origin of all absorption bands is ascribed to the ligand-to-metal charge transfer (LMCT) character. The solvent effect on the electronic structures and absorption spectra has also been studied by performing DFT and TDDFT calculations at the B3LYP/6-31G$^*$(cc-pVDZ-pp for Tc) level with the integral equation formalism polarized continuum model (IEFPCM) in different media. It is found that the absorption spectra display blue shift in different extents with the increase of solvent polarity.

Long noncoding RNA NEAT1 is involved in the protective effect of Klotho on renal tubular epithelial cells in diabetic kidney disease through the ERK1/2 signaling pathway

Yan-Lin Yang,Meng Xue,Yijie Jia,Fang Hu,Zongji Zheng,Ling Wang,Ze-Kun Si,Yaoming Xue 생화학분자생물학회 2020 Experimental and molecular medicine Vol.52 No.-

Klotho, an antiaging protein, has been shown to play a protective role in renal tubular epithelial-mesenchymal transition (EMT) during the development of diabetic kidney disease (DKD). Long noncoding RNAs (lncRNAs) participate in the progression of EMT in many diseases. However, the effect of Klotho on lncRNAs during the development of DKD is still unknown. In this study, we found that Klotho overexpression in high-fat diet (HFD)- and streptozotocin (STZ)- induced DKD mice significantly inhibited the expression of lncRNA nuclear-enriched abundant transcript 1 (Neat1). We demonstrated that NEAT1 was significantly upregulated in both bovine serum albumin (BSA)-stimulated HK2 cells and mice with HFD- and STZ-induced diabetes. In addition, we observed that Klotho displays colocalization with NEAT1. Furthermore, overexpression of Klotho can inhibit the high expression of NEAT1 in BSA-stimulated HK2 cells, while silencing Klotho can further upregulate the expression of NEAT1. Silencing NEAT1 in HK2 cells resulted in inhibition of the EMT-related markers alpha smooth muscle actin (α-SMA) and vimentin (VIM) and the renal fibrosis-related markers transforming growth factor-β1 (TGF-β1) and connective tissue growth factor (CTGF). The effect of NEAT1 on DKD was partly mediated by regulation of the ERK1/2 signaling pathway. Finally, we found that silencing NEAT1 can reverse the activation of EMT and fibrosis caused by Klotho silencing in a manner dependent on the ERK1/2 signaling pathway. These findings reveal a new regulatory pathway by which Klotho regulates ERK1/2 signaling via NEAT1 to protect against EMT and renal fibrosis, suggesting that NEAT1 is a potential therapeutic target for DKD.

Substituent Effect on the Structure and Biological Property of ^99mTc-Labeled Diphosphonates: Theoretical Studies

Qiu, Ling,Lin, Jian-Guo,Gong, Xue-Dong,Cheng, Wen,Luo, Shi-Neng Korean Chemical Society 2012 Bulletin of the Korean Chemical Society Vol.33 No.12

Theoretical calculations based on density functional theory (DFT) were performed to study the substituent effect on the geometric and electronic structures as well as the biological behavior of technetium-99m-labeled diphosphonate complexes. Optimized structures of these complexes are surrounded by six ligands in an octahedral environment with three unpaired 4d electrons ($d^3$ state) and the optimized geometry of $^{99m}Tc$-MDP agrees with experimental data. With the increase of electron-donating substituent or tether between phosphate groups, the energy gap between frontier orbitals increases and the probability of non-radiative deactivation via d-d electron transfer decreases. The charge distribution reflects a significant ligand-to-metal electron donation. Based on the calculated geometric and electronic structures and biologic properties of $^{99m}Tc$-diphosphonate complexes, several structure-activity relationships (SARs) were established. These results may be instructive for the design and synthesis of novel $^{99m}Tc$-diphosphonate bone imaging agent and other $^{99m}Tc$-based radiopharmaceuticals.