Effect of Temperature and Revolution on the Microstructure, Texture and Microhardness of the AZ80 Alloy Cup Prepared by Rotating Backward Extrusion

Xin Che,Qiang Wang,Xingwang Duan,Min Wang,Linfeng He,Miao Cao,Shuang Liu,Guanshi Zhang,Zhimin Zhang 대한금속·재료학회 2023 METALS AND MATERIALS International Vol.29 No.11

Microstructure evolution, phase development and mechanical property of AZ80 alloy cup with various processing temperatures(573 K, 613 K, 653 K) and rotating revolutions (N = 0, 5, 50, 100) during rotating backward extrusion (RBE)were explored. The study founded that reducing deformation temperature or increasing revolution could promote the grainrefinement and DRX proportion. And the sample deformed at the condition of 573 K and N = 100 exhibited the best grainrefinement effect (grain size was 2.5 μm, DRX ratio was up to 99.01%). The bulk eutectic phase existed at all deformationtemperatures, while the dynamic precipitation was only precipitated at temperature of 573 K and 613 K. Increasing thedeformation temperature or revolution could reduce the proportion of the second phase. And an increase in revolution or areduction of temperature would reduce the average size of second phase, due to the phase could be broken by large strainand resolved with elevated temperature. Moreover, increasing the revolution and deformation temperature could promotethe texture weakening, which would be contributed to the occurrence of new recrystallization grains with random orientationand the activation of non-basal slip system. The mechanical property of microhardness was significantly improved withrotating revolution increasing and deformation temperature decreasing. Supported by the grain refinement and dispersionstrengthening, the sample deformed at condition of 573 K and N = 100 achieved maximum hardness values of 96.3 HV.

Numerical and Experimental Analysis of Rotating Backward Extrusion as a New SPD Process

Xin Che,Qiang Wang,Beibei Dong,Mu Meng,Zhiming Zhang 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.12

Rotating backward extrusion (RBE) as a new severe plastic deformation technique is a continuous process to produce cylindricaltubes with fine grains and superior properties. In this study, the RBE process with an open punch was applied to theAZ80 alloy at 653 K, and the deformation mechanisms and the microstructure evolution were examined by the finite elementmethod (FEM) and thermal simulation experiment. The results showed that the effective strain of the RBE process was higherthan that of the conventional backward extrusion (CBE) process, and the strain increased with revolutions increasing. Thestrain improvement of the RBE process was related to the large cumulative plastic deformation imposed by the continuousrotation of the open punch. Furthermore, the extrusion load was reduced significantly in the RBE process comparing withthe CBE process, due to the change of friction stress and stress state of the materials. And the maximum load reduction ofthe FEM and experiment was 47.33% and 31.6%, respectively. The average grain size of the RBE sample could be reducedby up to 90% in the region A at 30 N compared with the CBE sample. The maximum increase in microhardness of the RBEsample relative to the CBE sample was 23% at 30 N in the region A. Therefore, the grain refinement and mechanical propertiesof the materials can be substantially improved by the RBE process.

Protective Role of Fucoidan in Cerebral Ischemia-Reperfusion Injury through Inhibition of MAPK Signaling Pathway

Che, Nan,Ma, Yijie,Xin, Yinhu The Korean Society of Applied Pharmacology 2017 Biomolecules & Therapeutics(구 응용약물학회지) Vol.25 No.3

Fucoidan has been reported to exhibit various beneficial activities ranging from to antivirus and anticancer properties. However, little information is available about the effects of fucoidan on cerebral ischemia-reperfusion injury (IRI). Our study aimed to explore the effects of fucoidan on cerebral IRI, as well as the underlying mechanisms. Sprague-Dawley (SD) rats were randomly subjected to four groups: Sham, IRI+saline (IRI+S), IRI+80 mg/kg fucoidan (IRI+F80), and IRI+160 mg/kg fucoidan (IRI+F160). Fucoidan (80 mg/kg or 160 mg/kg) was intraperitoneally injected from 7 days before the rats were induced to cerebral IRI model with middle cerebral artery occlusion (MCAO) method. At 24 h after reperfusion, neurological deficits and the total infarct volume were determined. The levels of inflammation-associated cytokines (interleukin (IL)-$1{\beta}$, IL-6, myeloperoxidase (MPO), and tumor necrosis factor (TNF)-${\alpha}$), oxidative stress-related proteins (malondialdehyde (MDA) and superoxide dismutase (SOD)) in the ischemic brain were measured by enzyme-linked immunosorbent assay (ELISA). Besides, the levels of apoptosis-related proteins (p-53, Bax, and B-cell lymphoma (Bcl)-2) and mitogen-activated protein kinase (MAPK) pathway (phosphorylation-extracellular signal-regulated kinase (p-ERK), p-c-Jun N-terminal kinase (JNK), and p-p38) were measured. Results showed that administration of fucoidan significantly reduced the neurological deficits and infarct volume compared to the IRI+S group in a dose-dependent manner. Also, fucoidan statistically decreased the levels of inflammation-associated cytokines, and oxidative stress-related proteins, inhibited apoptosis, and suppressed the MAPK pathway. So, Fucoidan plays a protective role in cerebral IRI might be by inhibition of MAPK pathway.

Suppression of MED19 expression by shRNA induces inhibition of cell proliferation and tumorigenesis in human prostate cancer cells

( Xin Gang Cui ),( Dan Feng Xu ),( Chao Lv ),( Fa Jun Qu ),( Jin He ),( Ming Chen ),( Yu Shan Liu ),( Yi Gao ),( Jian Ping Che ),( Ya Cheng Yao ),( Hong Yu Yu ) 생화학분자생물학회(구 한국생화학분자생물학회) 2011 BMB Reports Vol.44 No.8

MED19 is a member of the Mediator that plays a key role in the activation and repression of signal transduction or the regulation of transcription in carcinomas. To tested the functional role of MED19 in human prostate cancer, we downregulated MED19 expression in prostate cancer cells (PC-3 and DU145) by lentivirus- mediated short hairpin (shRNA), and analyzed the effect of inhibition of MED19 on prostate cancer cell proliferation and tumorigenesis. The in vitro prostate cancer cell proliferation, colony formation, and in vivo tumor growth in nude mice xenografts was significantly reduced after the downregulation of MED19. Knock- down of MED19 caused S-phase arrest and induced apoptosis via modulation of Bid and Caspase 7. It was suggested that MED19 serves as a novel proliferation regulator that promotes growth of prostate cancer cells. [BMB reports 2011; 44(8): 547-552]

Functional and Mechanistic Characterization of PRMT6- Regulated Autophagy in Hepatocellular Carcinoma

( Noelia Che ),( Kai Yu Ng ),( Man Tong ),( Michael Sy Huen ),( Xin Yuan Guan ),( Stephanie Ma ) 대한간학회 2018 춘·추계 학술대회 (KASL) Vol.2018 No.1

Aims: Autophagy is a critical survival factor for cancer cells, whereby it maintains cellular homeostasis including degradation of damaged organelles and unwanted proteins as well as the support of cellular biosynthesis in response to environmental stress, preventing cells from undergoing apoptosis. We investigated the functional role of protein arginine methyltransferase 6 (PRMT6) in regulation of autophagy and sorafenib resistance, aiming to provide novel therapeutic insights for HCC. Methods: We characterised the regulatory role of PRMT6 in autophagy by immunofluorescence puncta staining, transmission electron microscopy and immunoblot analyses. Identification and validation of potential PRMT6-interacting partners were performed through tandem affinity purification coupled with mass spectrometry profiling followed by co-immunoprecipitation. Subsequent in vitro and in vivo methylation assays found PRMT6 to methylate its binding partners to mediate arginine methylation for post-translational modification of proteins. Lentiviral-based overexpression and knockdown approaches were utilised to examine and explore the functional role of PRMT6-downstream effector in PRMT6-mediated autophagy deregulations in HCC. Results: Upon autophagy induction by Earle’s Balanced Salt Solution (EBSS) to mimic nutrient deprivation, hypoxia to mimic oxygen deprivation and sorafenib treatment, we demonstrated a negative correlation between expression of PRMT6 and LC3BII in HCC. Intriguingly, we identified and validated a number of autophagy-related proteins from mass spectrometry-based proteomics, including Bcl-2 associated athanogene 5 (BAG5), as PRMT6-binding partners. Mechanistically, PRMT6 methylates BAG5, leading to its protein degradation. We later confirmed that, BAG5, a downstream effector of PRMT6, promotes HCC tumorigenesis through autophagic alterations in vitro and in vivo. More importantly, data-mining in The Cancer Genome Atlas (TCGA) - Liver Cancer dataset found patients with higher BAG5 expression to display a significantly worst survival outcome, indicating its potential translational values. Conclusions: Our findings suggest PRMT6 down-regulation in HCC tumors to promote tumorigenicity and sorafenib resistance through an altered autophagic flux via BAG5 de-regulation.

Protective Role of Fucoidan in Cerebral Ischemia-Reperfusion Injury through Inhibition of MAPK Signaling Pathway

( Nan Che ),( Yijie Ma ),( Yinhu Xin ) 한국응용약물학회 2017 Biomolecules & Therapeutics(구 응용약물학회지) Vol.25 No.3

Fucoidan has been reported to exhibit various beneficial activities ranging from to antivirus and anticancer properties. However, little information is available about the effects of fucoidan on cerebral ischemia-reperfusion injury (IRI). Our study aimed to explore the effects of fucoidan on cerebral IRI, as well as the underlying mechanisms. Sprague-Dawley (SD) rats were randomly subjected to four groups: Sham, IRI+saline (IRI+S), IRI+80 mg/kg fucoidan (IRI+F80), and IRI+160 mg/kg fucoidan (IRI+F160). Fucoidan (80 mg/kg or 160 mg/kg) was intraperitoneally injected from 7 days before the rats were induced to cerebral IRI model with middle cerebral artery occlusion (MCAO) method. At 24 h after reperfusion, neurological deficits and the total infarct volume were determined. The levels of inflammation-associated cytokines (interleukin (IL)-1β, IL-6, myeloperoxidase (MPO), and tumor necrosis factor (TNF)-α), oxidative stress-related proteins (malondialdehyde (MDA) and superoxide dismutase (SOD)) in the ischemic brain were measured by enzyme-linked immunosorbent assay (ELISA). Besides, the levels of apoptosis-related proteins (p-53, Bax, and B-cell lymphoma (Bcl)-2) and mitogen-activated protein kinase (MAPK) pathway (phosphorylation-extracellular signalregulated kinase (p-ERK), p-c-Jun N-terminal kinase (JNK), and p-p38) were measured. Results showed that administration of fucoidan significantly reduced the neurological deficits and infarct volume compared to the IRI+S group in a dose-dependent manner. Also, fucoidan statistically decreased the levels of inflammation-associated cytokines, and oxidative stress-related proteins, inhibited apoptosis, and suppressed the MAPK pathway. So, Fucoidan plays a protective role in cerebral IRI might be by inhibition of MAPK pathway.

Ginseng consumption and risk of cancer: A meta-analysis

Jin, Xin,Che, Dao-biao,Zhang, Zhen-hai,Yan, Hong-mei,Jia, Zeng-yong,Jia, Xiao-bin The Korean Society of Ginseng 2016 Journal of Ginseng Research Vol.40 No.3

Background: The findings of currently available studies are not consistent with regard to the association between the risk of cancer and ginseng consumption. Therefore, we aimed to evaluate this association by conducting a meta-analysis of different studies. Methods: To systematically evaluate the effect of ginseng consumption on cancer incidence, six databases were searched, including PubMed, Ovid Technologies, Embase, The Cochrane Library, China National Knowledge Infrastructure, and Chinese VIP Information, from 1990 to 2014. Statistical analyses based on the protocol employed for a systematic review were conducted to calculate the summary relative risks (RRs) and 95% confidence intervals (CIs). Results: We identified nine studies, including five cohort studies, three case-control studies, and one randomized controlled trial, evaluating the association between ginseng consumption and cancer risk; these studies involved 7,436 cases and 334,544 participants. The data from the meta-analysis indicated a significant 16% lower risk of developing cancer in patients who consumed ginseng (RR = 0.84, 95% CI = 0.76-0.92), with evidence of heterogeneity (p = 0.0007, $I^2$ = 70%). Stratified analyses suggested that the significant heterogeneity may result from the incidence data for gastric cancer that were included in this study. Publication bias also showed the same result as the stratified analyses. In addition, subgroup analyses for four specific types of cancer (colorectal cancer, lung cancer, gastric cancer, and liver cancer) were also performed. The summary RRs for ginseng intake versus no ginseng consumption were 0.77 for lung cancer, 0.83 for gastric cancer, 0.81 for liver cancer, and 0.77 for colorectal cancer. Conclusion: The findings of this meta-analysis indicated that ginseng consumption is associated with a significantly decreased risk of cancer and that the effect is not organ specific.

Analysis of genetic diversity among indigenous landraces from sesame (Sesamum indicum L.) core collection in China as revealed by SRAP and SSR markers

Yan‐xin Zhang,Wei Hua,Lin‐han Wang,Zhuo Che,Xiu‐rong Zhang 한국유전학회 2010 Genes & Genomics Vol.32 No.3

The molecular genetic diversity of 404 indigenous landraces from sesame core collection in China were evaluated by 11SRAP and 3 SSR markers, 175 fragments were generated, of which 126 were polymorphic with an average polymorphism rate of 72%. Jaccard’s genetic similarity coefficients (GS=0.7130), Nei's gene diversity (h=0.2418) and Shannon's Information index (I=0.3847) were calculated, a dendrogram of the 404 landraces was made, landraces from various zones were distributed throughout the dendrogram, accessions from different agro‐ecological zones were indistinguishable by cluster analysis, geographical separation did not generally result in greater genetic distance, a similar pattern was obtained using principal coordinates (PCO) analysis. As to seven agro‐ecological zones, the maximum Nei’s gene diversity (h = 0.2613)and Shannon index (I = 0.3980) values in zone VII indicated that they were genetically more diverse than those in other zones, while the least genetically diverse region was zone III (h = 0.1772, I = 0.2858). Nei's genetic identity and genetic distance among landraces from seven agro‐ecological zones were also analyzed, the genetic relationship of seven zones was inferred using the UPGMA method. This study demonstrated that SRAP and SSR markers were appropriate for evaluation of sesame genetic diversities. There existed extensive genetic diverse among indigenous landraces and the abundance of genetic diversity of landraces in different agro‐ecological zones was various. Understanding of these characteristics of indigenous landraces in China can provide theoretical foundation for further collection, effective protection and reasonable utilization of these sesame landraces in breeding.

Ab Initio Study of Mechanism of Forming Germanic Bis-Heterocyclic Compound between Dimethyl-Germylene Carbene (Me₂Ge=C:) and Acetone

Lu, Xiuhui,Che, Xin,Lian, Zhenxia,Li, Yongqing Korean Chemical Society 2011 Bulletin of the Korean Chemical Society Vol.32 No.1

The mechanism of the cycloaddition reaction of forming germanic bis-heterocyclic compound between singlet dimethylgermylene carbene and acetone has been investigated with CCSD(T)//B3LYP/6-$31G^*$ method. From the potential energy profile, it can be predicted that, this reaction has one dominant channel. The presented rule of this dominant channel is that the two reactants firstly form a four-membered ring carbene (RC4) through the [2+2] cycloaddition reaction. Due to $sp^2$ hybridization of carbene C atom in RC4, RC4 further combines with acetone to form a reactant complexe (RC5). Due to the further $sp^3$ hybridization of carbene C atom in RC4, RC5 isomerizes to a germanic bisheterocyclic compound (P6) via the transition state (TS5).

Myricitrin exerts protective effect on retina in diabetic retinopathy via modulating oxidative stress expression of VEGF and apoptosis in experimental rats: a docking confirmation study

Jiang Jing,Che Xin,Qian Yiwen,Lu Shiheng,Wang Zhiliang 대한독성 유전단백체 학회 2022 Molecular & cellular toxicology Vol.18 No.2

Background The present study investigates the protective effect of myricitrin (MCT) on the retinal tissues in diabetic retinopathy of diabetic rats. Objective The diabetic rat model was created by treating the rats with streptozotocin along with high-energy diet. The blood glucose was evaluated by glucose estimation kit, and rats measuring glucose ≥ 12.00 mmol/L were considered diabetic and were selected for the study. The diabetes-induced rats were divided randomly as diabetic control rats (vehicle treated) (DB), diabetic rats MCT (100 mg/kg) (DB + MCT 100 mg/kg) and diabetic rats MCT 200 mg/kg (DB + MCT 200 mg/kg). Rats received MCT for 12 weeks via oral route daily. The rats after 12 weeks were sacrificed, and the eyes were removed. The retina tissue was evaluated for thickness, oxidative stress markers, levels of VEGF and Bax and Bcl-2. In silico docking analysis was done by Autodock Vina tools for target confirmation of MCT. Results MCT decreased the serum glucose levels and also improved the body weight in diabetic rats. MCT improved thickness and apoptosis of cells. It was also found that MCT decreased oxidative stress, and improved levels of VEGF in retinal tissues of diabetic rats. MCT also exerted anti-apoptotic activity as shown by over-expression of Bcl-2 and suppression of Bax in retinal tissues of rats. Docking study confirmed potential binding affinity of MCT with VEGF. Conclusions MCT could be a potential therapeutic molecule in treating diabetic retinopathy which could modulate glucose levels, oxidative stress and levels of VEGF in diabetic rats.