Promoter Analysis of Bombyx mori Nucleopolyhedrovirus Ubiquitin Gene

Xu’ai Lin,Yin Chen,Yongzhu Yi,Jie Yan,Zhifang Zhang 한국미생물학회 2008 The journal of microbiology Vol.46 No.4

The aim of this study was to analyze the characteristics of Bombyx mori nucleopolyhedrovirus (BmNPV) ubiquitin gene promoter and the effects of conserved motifs, such as TAAG, TATA, and CAAT, along with baculovirus enhancer homologous region 3 (hr3), on promoter activity. Ubiquitin gene of BmNPV was expressed during the late phase of virus infection. In the presence of viral factors, significant reduction of promoter activity was observed by deletion of -382 to -124 bp upstream of ATG. The fragment between -187 and -383 bp upstream of ATG, including distal TAAG, CAAT motif, and TATA box, could also drive expression of the reporter gene. The mutation of cis-elements TATA boxes and TAAG motifs significantly decreased the promoter’s activity, while CAAT mutations enhanced promoter activity by 2- or 3-fold, as compared with the native promoter. In the presence of BmNPV, hr3, both located downstream of the reporter gene of the same vector, and separate vector, could significantly enhance transcription activity of ubiquitin promoter as compared to the control. We concluded that BmNPV ubiquitin gene might be regulated by dual sets of promoter elements, where TAAG and TATA box may positively regulate the expression of ubiquitin, while CAAT motif functions as a negative regulator. Viral factor(s) play an important role in the co-activation of hr3 and promoter.

Effect of MgO on migration and distribution of chromium in stainless-steel slag glass–ceramics and glass properties

Zhifang Tong,Congcong Xu,Jiaxing Wang,Zhiheng Jia 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.1

Herein, stainless-steel slag was used to prepare glass–ceramics. The effects of the MgO content on the occurrence, distributionstate, and migration behavior of Cr in glass–ceramics as well as glass properties were systematically studied. Results revealedthat in the nucleation stage, the number of Cr-spinel (Cr spinel) nanocrystals initially increased and then decreased with theincreasing MgO content. In the crystallization stage, the diopside crystal phase considered Cr-spinel nanocrystals asheterogeneous nuclei, which gradually nucleated and grew. Transmission electron microscopy and X-ray photoelectronspectroscopy analyses showed that part of Cr in the spinel migrated into the diopside lattice and some other parts remainedin the Cr spinel wrapped by the diopside. Cr in the glass phase also diffused and migrated into the diopside lattice with theformation of diopside crystals. When the MgO content was 12.3 wt.%, 97.33 wt.% of the total amount of Cr was observedin the diopside crystal phase and the leaching concentration of Cr in the glass–ceramics was only 0.006 mg/L. The compressivestrength of the glass–ceramics was 261.7 MPa, and the Vickers hardness was 1007.7 HV. The research results providetheoretical and technical support for strengthening Cr fixation and realizing harmless and high-value utilization of stainlesssteelslag.

TNF-α-Induced SOX5 Upregulation Is Involved in the Osteogenic Differentiation of Human Bone Marrow Mesenchymal Stem Cells Through KLF4 Signal Pathway

Xu, Lijun,Zheng, Lili,Wang, Zhifang,Li, Chong,Li, Shan,Xia, Xuedi,Zhang, Pengyan,Li, Li,Zhang, Lixia Korean Society for Molecular and Cellular Biology 2018 Molecules and cells Vol.41 No.6

Postmenopausal osteoporosis (PMOP) is a common systemic skeletal disease characterized by reduced bone mass and microarchitecture deterioration. Although differentially expressed SOX5 has been found in bone marrow from ovariectomized mice, its role in osteogenic differentiation in human mesenchymal stem cells (hMSCs) from bone marrow in PMOP remains unknown. In this study, we investigated the biological function of SOX5 and explore its molecular mechanism in hMSCs from patients with PMOP. Our findings showed that the mRNA and protein expression levels of SOX5 were upregulated in hMSCs isolated from bone marrow samples of PMOP patients. We also found that SOX5 overexpression decreased the alkaline phosphatase (ALP) activity and the gene expression of osteoblast markers including Collagen I, Runx2 and Osterix, which were increased by SOX5 knockdown using RNA interference. Furthermore, $TNF-{\alpha}$ notably upregulated the SOX5 mRNA expression level, and SOX5 knockdown reversed the effect of $TNF-{\alpha}$ on osteogenic differentiation of hMSCs. In addition, SOX5 overexpression increased Kruppel-like factor 4 (KLF4) gene expression, which was decreased by SOX5 silencing. KLF4 knockdown abrogated the suppressive effect of SOX5 overexpression on osteogenic differentiation of hMSCs. Taken together, our results indicated that $TNF-{\alpha}$-induced SOX5 upregulation inhibited osteogenic differentiation of hMSCs through KLF4 signal pathway, suggesting that SOX5 might be a novel therapeutic target for PMOP treatment.

Anti-disturbance Position Sensorless Control of PMSM Based on Improved Sliding Mode Observer with Suppressed Chattering and No Phase Delay

Xu Yanping,Wang Chen,Yuan Weiwen,Li Zhifang,Yin Zhonggang 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.4

In the position sensorless control of permanent magnet synchronous motor (PMSM), the traditional sliding mode observer (SMO) uses the switching function, which presents serious chattering. Otherwise, the traditional SMO uses a low-pass filter to filter the harmonic components in the estimated back-EMF. The low-pass filter usually causes phase delay in the estimated rotor position. These problems restrict the further development of SMO. In this paper, an improved sliding mode observer (ISMO) with suppressed chattering and no phase delay is studied. In the ISMO, a sine saturation function is designed as the control function, and a synchronous reference frame filter (SRFF) is designed to eliminate the phase delay of ISMO. Different from other filters, the SRFF can not only filter out the harmonic components in the estimated back-EMF, but also effectively makes the phase delay almost zero. In addition, in order to improve the poor anti-disturbance performance of position sensorless control, a load disturbance observer (LDO) is introduced on the basis of the ISMO. The experimental results prove the effectiveness of the ISMO, and the addition of LDO improves the anti-disturbance ability of the system.

Anterior Gradient 3 Promotes Breast Cancer Development and Chemotherapy Response

Qiao Xu,Ying Shao,Jinman Zhang,Huikun Zhang,Yawen Zhao,Xiaoli Liu,Zhifang Guo,Wei Chong,Feng Gu,Yongjie Ma 대한암학회 2020 Cancer Research and Treatment Vol.52 No.1

Purpose Anterior gradient 3 (AGR3) belongs to human anterior gradient (AGR) family. The function of AGR3 on cancer remains unknown. This research aimed to investigate if AGR3 had prognostic values in invasive ductal carcinoma (IDC) of breast cancer and could promote tumor progression. Materials and Methods AGR3 expression was detected in breast benign lesions, ductal carcinoma in situ and IDC by immunohistochemistry analysis. AGR3’s correlations with clinicopathological features and prognosis of IDC patients were analyzed. By cell function experiments, collagen gel droplet-embedded culture drug sensitivity test and cytotoxic analysis, AGR3’s impacts on proliferation, invasion ability, and chemotherapeutic drug sensitivity of breast cancer cells were also detected. Results AGR3 was up-regulated in luminal subtype of histological grade I-II of IDC patients and positively correlated with high risks of recurrence and distant metastasis. AGR3 high expression could lead to bone or liver metastasis and predict poor prognosis of luminal B. In cell lines, AGR3 could promote proliferation and invasion ability of breast cancer cells which were consistent with clinical analysis. Besides, AGR3 could indicate poor prognosis of breast cancer patients treated with taxane but a favorable prognosis with 5-fluoropyrimidines. And breast cancer cells with AGR3 high expression were resistant to taxane but sensitive to 5-fluoropyrimidines. Conclusion AGR3 might be a potential prognostic indicator in luminal B subtype of IDC patients of histological grade I-II. And patients with AGR3 high expression should be treated with chemotherapy regimens consisting of 5-fluoropyrimidines but no taxane.

TNF-α-Induced SOX5 Upregulation Is Involved in the Osteogenic Differentiation of Human Bone Marrow Mesenchymal Stem Cells Through KLF4 Signal Pathway

Lijun Xu,Lili Zheng,Zhifang Wang,Chong Li,Shan Li,Xuedi Xia,Pengyan Zhang,Li Li,Lixia Zhang 한국분자세포생물학회 2018 Molecules and cells Vol.41 No.6

Postmenopausal osteoporosis (PMOP) is a common sys-temic skeletal disease characterized by reduced bone mass and microarchitecture deterioration. Although differentially expressed SOX5 has been found in bone marrow from ovariectomized mice, its role in osteogenic differentiation in human mesenchymal stem cells (hMSCs) from bone marrow in PMOP remains unknown. In this study, we investigated the biological function of SOX5 and explore its molecular mechanism in hMSCs from patients with PMOP. Our findings showed that the mRNA and protein expression levels of SOX5 were upregulated in hMSCs isolated from bone marrow samples of PMOP patients. We also found that SOX5 overexpression decreased the alkaline phosphatase (ALP) activity and the gene expression of osteoblast markers including Collagen I, Runx2 and Osterix, which were increased by SOX5 knockdown using RNA interference. Furthermore, TNF- notably upregulated the SOX5 mRNA expression level, and SOX5 knockdown reversed the effect of TNF- on osteogenic differentiation of hMSCs. In addition, SOX5 overexpression increased Kruppel-like factor 4 (KLF4) gene expression, which was decreased by SOX5 silencing. KLF4 knockdown abrogated the suppressive effect of SOX5 overexpression on osteogenic differentiation of hMSCs. Taken together, our results indicated that TNF--induced SOX5 upregulation inhibited osteogenic differentiation of hMSCs through KLF4 signal pathway, suggesting that SOX5 might be a novel therapeutic target for PMOP treatment.

Cosmogenic nuclides (10Be and 26Al) erosion rate constraints in the Badain Jaran Desert, northwest China: implications for surface erosion mechanisms and landform evolution

Tong Zhao,Wenjing Liu,Zhifang Xu,Taoze Liu,Sheng Xu,Lifeng Cui,Chao Shi 한국지질과학협의회 2019 Geosciences Journal Vol.23 No.1

Both tectonics and climate affect surface erosion and change the landform. Long-term surface erosion rates determined by in situ produced cosmogenic nuclides are useful quantitative constraints for landform evolution in geological time scale. Measurements of cosmogenic 10Be and 26Al in the granitic rocks exposed in the Badain Jaran Desert, give a mean erosion rate of 7.3 ± 2.6 m/Ma, which is an order of magnitude higher than those reported in other extremely arid regions. Tectonic activity is supposed to be the first order control on regional erosion rate by comparing the 10Be erosion rates of arid regions with different precipitation ranges and tectonic activities worldwide. However the higher erosion rates in the Badain Jaran Desert compared with other arid regions within the stable tectonic background were attributed to the wind erosion and periodically warmer and wetter climate since late Pleistocene. Besides, the estimated eroded mass flux of 7.8 × 104 t/y suggests that erosion products of bedrocks in the Badian Jaran Desert only contribute minor desert deposits, which indicates massive exogenous materials input to the desert.

Soft-Switching Single-Stage Current-Fed Full-Bridge Isolated Converter for High Power AC/DC Applications

Yu Zhang,Chushan Li,Zhifang Cao,David Xu 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

In this paper, a novel single-stage softswitching current-fed full-bridge AC/DC converter is proposed. By adding an additional commutation path, softswitching can be realized for all power devices. The power density is also enhanced by eliminating the DC capacitor. Meanwhile, the conduction loss is also lowered through the use of the additional commutation path. Furthermore, the control strategy for the proposed converter is compatible with that for traditional PFC converter. This facilitates the use of well-developed analog control IC such as UC3854. In this paper, the topology derivation and circuit operational analysis are given. The control strategy is introduced. A simulation is carried out to verify the circuit functionality.