Fabrication of Al–Ti–B Grain Refiner Using Machining Ti Chips, Reaction Mechanisms and Grain Refinement Performance in Pure Al

Maoliang Hu,Fei Wang,Bo Jiang,Huasheng Wang,Yile Liu,Zesheng Ji 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

Al–5Ti–1B grain refiner was successfully prepared with the reaction of Ti chips produced during machining and KBF4inpure aluminum melt. In order to illustrate the reaction mechanism of Ti chips, the effect of different feeding ways and reactiontimes of Ti chips on microstructure and refining performance of Al–5Ti–1B was systematically investigated by opticalmicroscope, scanning electron microscopy and X-ray diffractometer. The results show that, in three feeding ways, includingadding Ti chips firstly, adding KBF4firstly and adding both Ti chips and KBF4in the form of prefabricated blocks, the bestrefining performance of Al–5Ti–1B is the feeding way of using the prefabricated block. TiB2and TiAl3as effective heterogeneousnuclei are formed simultaneously around the Ti chips. The average grain size of pure aluminum is refined to about206.80 μm. The reaction time mainly affects the dissolution process of Ti chips and the average size of TiAl3. With the reactiontime from 60 min to 90 min and then to 120 min, the average size of TiAl3increases from 10.74 μm to 14.30 μm and thento 15.39 μm. During the dissolution process, Ti chips undergo a transition from a thermal isolation layer to a supersaturatedzone of Ti atoms. Based on the analysis of the dissolution process of Ti chips, the dissolution model is proposed. Al–5Ti–1B has the best refining performance at 90 min of the reaction time, which can refine pure aluminum to about 223.65 μm.

Influence of Microstructure and Mechanical Properties on Formability in High Strain Rate Rolled AZ31 Magnesium Alloy Sheets

Fubao Liu,Xiao Liu,Biwu Zhu,Hui Yang,Gang Xiao,Mingyue Hu 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.6

High strain-rate rolling (≥ 10 s−1) has been successfully employed to produce AZ31 magnesium alloy sheets to a high reductionof 82% with a fine grain structure in a single pass. The rolled sheets inevitably undertake various forming processessuch as press and deep forming in the fabrication stage. To investigate the formability, the Erichsen tests were carried out onhigh strain rate rolled AZ31 magnesium alloy sheets at room temperature. The relationship among mechanical properties,microstructure and formability were investigated. The crack behavior during Erichsen tests was also studied. It was foundthat the formability was related to the lowest in-plane tensile strengthen and dislocation density of initial microstructure. The competitive relationship between micro-crack and twinning/shear bands would also influence the formability of highstrain rate rolled magnesium alloy sheets. Deformed shear band with substaintial twins prohibits the crack extension andenhances strengthen of materials in front of crack tip.

Identification of QTLs associated with the anaerobic germination potential using a set of Oryza nivara introgression lines

Licheng Liu,Xiaoxiang Li,Sanxiong Liu,Jun Min,Wenqiang Liu,Xiaowu Pan,Baohua Fang,Min Hu,Zhongqi Liu,Yongchao Li,Haiqing Zhang 한국유전학회 2021 Genes & Genomics Vol.43 No.4

Background Rice (Oryza sativa L.) is an important crop and a staple food for half of the population around the world. The recent water and labor shortages are encouraging farmers to shift from traditional transplanting to direct-seeding. However, poor germination and slow elongation of the coleoptile constrains large-scale application of direct-seeding. Objective Thisstudy was aimed to investigate the genetic basis of the anaerobic germination(AG) potential using a set of Oryza nivara (O. nivara) introgressionlines (ILs). Methods Inthis study, a total of 131 ILs were developed by introducing O. nivara chromosomesegments into the elite indica rice variety 93-11 through advanced backcrossingand repeated selfng. A high-density genetic map has been previouslyconstructed with 1,070 bin-markers. The seeds of ILs were germinated and usedto measure coleoptile length under normal and anaerobic conditions. QTLsassociated with AG potential were determined in rice. Results Basedon the high-density genetic map of the IL population, two QTLs, qAGP1 and qAGP3 associated with AG tolerance were characterized and locatedon chromosomes 1 and 3, respectively. Each QTL explained 15% of the phenotypic variance.Specifcally, the O. nivara-derived chromosomesegments of the two QTLs were positively tolerance to anaerobic condition byincreasing coleoptile length. In a further analysis of public transcriptomedata, a total of 26 and 36 genes within qAGP1 and qAGP3 were transcriptionallyinduced by anaerobic stress, respectively. Conclusions Utilizationof O. nivara-derived alleles at qAGP1 and qAGP3 can potentially enhance tolerance to anaerobic stress at thegermination stage in rice, thereby accelerating breeding of rice varieties tobe more adaptative for direct-seeding.

In Vitro Evaluation and Monitoring of the Expression Level and Localization of Aldose Reductase Using Functionalized Quantum Dots and EGFP

Xiaomin Liu,Chengbin Yang,Jing Liu,Jianwei Liu,Rui Hu,Hongwei Lian,Guimiao Lin,Liwei Liu,Ken-Tye Yong,Ling Ye 한국생물공학회 2015 Biotechnology and Bioprocess Engineering Vol.20 No.4

The optimization of aldose reductase (AR) expression levels and tracking of the AR expression sites within the cell is an essential step in developing a platform for the effective production of aldose reductase inhibitors (ARIs). In this study, we have demonstrated the use of both immunocytochemistry and quantum dots-based immunofluorescence techniques for observing and detecting the expression level and localization of AR in the cytoplasm and cell membrane of a eukaryotic cell model with high levels of AR protein expression. Our results show that high expression levels of human AR can be achieved using the eukaryotic cell model that we have developed. The overexpressed AR can be used for translational studies of hAR and the screening of ARIs. More importantly, the use of the established quantum dots-based immunofluorescence technique in the intracellular labeling of AR allows the determination of the expression and distribution of the AR gene. Overall, the use of the interdisciplinary approach of both genetic engineering and quantum dot-based immunofluorescence allows not only the effective production of a desired protein, but also the determination of the cellular localization of such an expressed protein.

MiR-1224-5p modulates osteogenesis by coordinating osteoblast/osteoclast differentiation via the Rap1 signaling target ADCY2

Hu Liangcong,Xie Xudong,Xue Hang,Wang Tiantian,Panayi Adriana C.,Lin Ze,Xiong Yuan,Cao Faqi,Yan Chengcheng,Chen Lang,Cheng Peng,Zha Kangkang,Sun Yun,Liu Guodong,Yu Chenyan,Hu Yiqiang,Tao Ranyang,Zhou 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

MicroRNAs (miRNAs) broadly regulate normal biological functions of bone and the progression of fracture healing and osteoporosis. Recently, it has been reported that miR-1224-5p in fracture plasma is a potential therapy for osteogenesis. To investigate the roles of miR-1224-5p and the Rap1 signaling pathway in fracture healing and osteoporosis development and progression, we used BMMs, BMSCs, and skull osteoblast precursor cells for in vitro osteogenesis and osteoclastogenesis studies. Osteoblastogenesis and osteoclastogenesis were detected by ALP, ARS, and TRAP staining and bone slice resorption pit assays. The miR-1224-5p target gene was assessed by siRNA-mediated target gene knockdown and luciferase reporter assays. To explore the Rap1 pathway, we performed high-throughput sequencing, western blotting, RT-PCR, chromatin immunoprecipitation assays and immunohistochemical staining. In vivo, bone healing was judged by the cortical femoral defect, cranial bone defect and femoral fracture models. Progression of osteoporosis was evaluated by an ovariectomy model and an aged osteoporosis model. We discovered that the expression of miR-1224-5p was positively correlated with fracture healing progression. Moreover, in vitro, overexpression of miR-1224-5p slowed Rankl-induced osteoclast differentiation and promoted osteoblast differentiation via the Rap1-signaling pathway by targeting ADCY2. In addition, in vivo overexpression of miR-1224-5p significantly promoted fracture healing and ameliorated the progression of osteoporosis caused by estrogen deficiency or aging. Furthermore, knockdown of miRNA-1224-5p inhibited bone regeneration in mice and accelerated the progression of osteoporosis in elderly mice. Taken together, these results identify miR-1224-5p as a key bone osteogenic regulator, which may be a potential therapeutic target for osteoporosis and fracture nonunion.

CT Findings of Persistent Pure Ground Glass Opacity: Can We Predict the Invasiveness?

Liu, Li-Heng,Liu, Ming,Wei, Ran,Jin, Er-Hu,Liu, Yu-Hui,Xu, Liang,Li, Wen-Wu,Huang, Yong Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.5

Background: To investigate whether CT findings can predict the invasiveness of persistent cancerous pure ground glass opacity (pGGO) by correlating the CT imaging features of persistent pGGO with pathological changes. Materials and Methods: Ninety five patients with persistent pGGOs were included. Three radiologists evaluated the morphologic features of these pGGOs at high resolution CT (HRCT). Binary logistic regression was used to assess the association between CT findings and histopathological classification (pre-invasive and invasive groups). Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of diameters. Results: A total of 105 pGGOs were identified. Between pre-invasive (atypical adenomatous hyperplasia, AAH, and adenocarcinoma in situ, AIS) and invasive group (minimally invasive adenocarcinoma, MIA and invasive lung adenocarcinomas, ILA), there were significant differences in diameter, spiculation and vessel dilatation (p<0.05). No difference was found in air-bronchogram, bubble-lucency, lobulated-margin, pleural indentation or vascular convergence (p>0.05). The optimal threshold value of the diameters to predict the invasiveness of pGGO was 12.50mm. Conclusions: HRCT features can predict the invasiveness of persistent pGGO. The pGGO with a diameter more than 12.50mm, presences of spiculation and vessel dilatation are important factors to differentiate invasive adenocarcinoma from pre-invasive cancerous lesions.

Prevalence and Related Factors of EPS among Schizophrenic Inpatients

Liu, Lian-Qi,Liu, Xian-Chen,Hu, Lei,Chen, Kun,Li, Chuan-Qi 용인정신의학연구소 1998 용인정신의학보 Vol.5 No.1

HSP70 attenuates compression-induced apoptosis of nucleus pulposus cells by suppressing mitochondrial fission via upregulating the expression of SIRT3

Hu Binwu,Wang Peng,Zhang Shuo,Liu Weijian,Lv Xiao,Shi Deyao,Zhao Lei,Liu Hongjian,Wang Baichuan,Chen Songfeng,Shao Zengwu 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Compression-induced apoptosis of nucleus pulposus (NP) cells plays a pivotal role in the pathogenesis of intervertebral disc degeneration (IVDD). Recent studies have shown that the dysregulation of mitochondrial fission and fusion is implicated in the pathogenesis of a variety of diseases. However, its role in and regulatory effects on compression-induced apoptosis of NP cells have not yet been fully elucidated. Heat shock protein 70 (HSP70) is a major cytoprotective heat shock protein, but its physiological role in IVDD, especially its effect on mitochondrial fission and fusion, is still unknown. Herein, we found that compression could induce mitochondrial fission, which ultimately trigger apoptosis of NP cells via the mitochondrial apoptotic pathway. In addition, we identified the cytoprotective effects of HSP70 on NP cells, and we found that promoting the expression of HSP70 could protect NP cells from abnormal mechanical loading in vitro and in vivo. Finally, we showed that HSP70 inhibited compression-induced mitochondrial fission by promoting SIRT3 expression, thereby attenuating mitochondrial dysfunction and the production of reactive oxygen species and ultimately inhibiting the mitochondrial apoptotic pathway in NP cells. In conclusion, our results demonstrated that HSP70 could attenuate compression-induced apoptosis of NP cells by suppressing mitochondrial fission via upregulating SIRT3 expression. Promoting the expression of HSP70 might be a novel strategy for the treatment of IVDD.

Transmission accuracy–axial backlash–fatigue life-driven tolerance optimization of planetary roller screw mechanism

Liu Genshen,Wei Peitang,Liu Huaiju,Du Xuesong,Hu Rui,He Huilin,Zhou Pengliang,Tan Xiaoqing 한국CDE학회 2023 Journal of computational design and engineering Vol.10 No.6

The planetary roller screw mechanism (PRSM) is an advanced linear transmission device. The relationship between tolerance allocation and performance risk still remains elusive, which is a challenge for its future applications. This work proposes a novel transmission accuracy–axial backlash–fatigue life-driven tolerance optimization method for the screw, roller, and nut of PRSM. A computational framework for PRSM transmission accuracy, axial backlash, and fatigue life calculation is developed to work on the parametric variation of design parameters including the eccentric, pitch, nominal diameter, and flank angle. Combinations of parametric variation are obtained by the Latin hypercube sampling-based tolerance statistical model to rapidly evaluate PRSM performance risk under operation conditions and tolerance parameters. The optimal tolerance parameters with the expanded width of tolerance interval and the minimum PRSM performance risk probability are obtained using the non-dominated sorting genetic algorithm. Results reveal that PRSM performance risk probabilities change from 89.25 to 68.72% and 58.1 to 56.86%, with 29.94 and 17.38% tolerance interval width increase under the high-precision and heavy-loading operation cases studied, respectively.

STABILITY OF THE MILSTEIN METHOD FOR STOCHASTIC DIFFERENTIAL EQUATIONS WITH JUMPS

Liu Hu,Siqing Gan 한국전산응용수학회 2011 Journal of applied mathematics & informatics Vol.29 No.5

In this paper the Milstein method is proposed to approximate the solution of a linear stochastic differential equation with Poisson-driven jumps. The strong Milstein method and the weak Milstein method are shown to capture the mean square stability of the system. Furthermore using some technique, our result shows that these two kinds of Milstein methods can well reproduce the stochastically asymptotical stability of the system for all suffciently small time-steps. Some numerical experiments are given to demonstrate the conclusions.