选择性激光熔化打印等原子比NiCoCr中熵合金力学性能与温度的相关性

研究工艺参数对选择性激光融化制备的等原子比NiCoCr中熵合金致密度、显微组织和力学性能的影响,以及该合金的力学性能与温度的相关性。结果表明,显微组织和力学性能不与激光的体积能量密度呈线性相关,其主要是受扫描速度和激光功率影响。扫描速度为800 mm/s且激光功率为250W为最佳的工艺参数,但是在该工艺参数下的体积能量密度仅为57 J/mm^(3),低于最高能量密度68 J/mm^(3)。以最佳工艺制备的样品在77、200和293 K温度下测得的屈服强度分别为~819、~709和~618 MPa。通过计算揭示力学性能的温度相关性方程,并得到实验验证。

Self-healed microcracks in polymer bonded explosives via thermoreversible covalent bond and hydrogen actions

Polymeric materials used for the polymer bonded explosive(PBX)or other energetic composite materials(ECMs)that simultaneously possess excellent mechanical properties and high self-healing ability,convenient healing,and facile fabrication are always a huge challenge.Herein,self-healing linear polyurethane elastomers(PTMEG2000-IPDI-DAPU,denoted as 2I-DAPU)with high healing efficiency and mechanical properties were facilely fabricated by constructing reversible covalent bonds and dynamic hard domains into polymer chains.Furthermore,a TATB-based PBX using as-prepared 2I-DAPU polymer as the binder was constructed,disclosing an excellent self-healing property to heal cracks generated during fabrication,transportation and storage.The damage healing manner of such a PBX sample was investigated by means of prefabricated damage through mechanical load,heal treatment via heating at high temperature,and CT-scanning the inner structure and mechanical property characterization via Brazilian test.The self-healing mechanism of internal damage in PBX was preliminarily explored.We propose that this 2I-DAPU binder with Diels-Alder bonds could generate plentiful active surface groups resulting from damage and drive self-healing at fitting temperature and increase the slightly packed hard phase via incorporating a small amount of hydrogen bonds.This work may offer a novel strategy for improving mechanical property and healing ability in the field of self-healing material which could help expand its applications with enhanced versatility in mechanical-enhanced functional materials.

LINC01268 promotes epithelial-mesenchymal transition,invasion and metastasis of gastric cancer via the PI3K/Akt signaling pathway and targeting MARCKS

BACKGROUND Long non-coding RNAs(lncRNAs)with differential expression characteristics have been found to be closely related to the tumorigenesis and development of gastric cancer(GC),but their specific mechanisms and roles still need to be further elucidated.AIM To investigate the expression of LINC01268 in GC and its mechanism of affecting GC progression.METHODS Real-time quantitative polymerase chain reaction was used to detect the expression of LINC01268 in GC tissues,cell lines and plasma.The Kaplan-Meier method was used to evaluate the value of LINC01268 in the prognostication of GC patients.An receiver operating characteristic curve was constructed to evaluate the value of LINC01268 in the diagnosis of GC.Transwell migration and invasion assays and wound healing assays were used to confirm the effect of LINC01268 on the invasion and migration of GC cells.The regulatory relationship between LINC01268 and myristoylated alanine rich protein kinase C substrate(MARCKS),the PI3K/Akt signaling pathway,and the epithelial-mesenchymal transition(EMT)process in GC was demonstrated by western blot analysis.RESULTS The expression of LINC01268 was increased in GC tissues and cell lines.The expression level of LINC01268 was significantly correlated with lymph node metastasis,TNM stage,and tumor differentiation in patients with GC.Over-expression of LINC01268 indicated a poor prognosis for patients with GC,and it had a certain auxiliary diagnostic value for GC.In vitro functional experiments proved that the abnormal expression of LINC01268 further activated the PI3K/Akt signaling pathway and promoted EMT by targeting and regulating MARCKS and ultimately promoted the invasion and metastasis of GC.CONCLUSION This study elucidates that LINC01268 in GC may be an oncogene that further activates the PI3K/Akt signaling pathway and EMT by targeting and regulating MARCKS,and ultimately promotes the invasion and metastasis of GC.LINC01268 may be a potential effective target for the treatment of GC.

Clinical comparison of antrum-preserving double tract reconstruction vs roux-en-Y reconstruction after gastrectomy for Siewert types Ⅱ and Ⅲ adenocarcinoma of the esophagogastric junction

AIM:To explore a reasonable method of digestive tract reconstruction,namely,antrum-preserving double-tract reconstruction(ADTR),for patients with adenocarcinoma of the esophagogastric junction(AEG) and to assess its efficacy and safety in terms of longterm survival,complications,morbidity and mortality.METHODS:A total of 55 cases were retrospectively collected,including 18 cases undergoing ADTR and 37 cases of Roux-en-Y reconstruction(RY) for AEG(Siewert types Ⅱ and Ⅲ) at North Sichuan Medical College. The cases were divided into two groups. The clinicopathological characteristics,perioperative outcomes,postoperative complications,morbidity and overall survival(OS) were compared for the two different reconstruction methods.RESULTS:Basic characteristics including sex,age,body mass index(BMI),Siewert type,p T status,p N stage,and lymph node metastasis were similar in the two groups. No significant differences were found between the two groups in terms of perioperative outcomes(including the length of postoperative hospital stay,operating time,and intraoperative blood loss) and postoperative complications(consisting of anastomosis-related complications,wound infection,respiratory infection,pleural effusion,lymphorrhagia,and cholelithiasis). For the ADTR group,perioperativerecovery indexes such as time to first flatus(P = 0.002) and time to resuming a liquid diet(P = 0.001) were faster than those for the RY group. Moreover,the incidence of reflux esophagitis was significantly decreased compared with the RY group(P = 0.048). The postoperative morbidity and mortality rates for overall postoperative complications and the rates of tumor recurrence and metastasis were not significantly different between the two groups. Survival curves plotted using the Kaplan-Meier method and compared by log-rank test demonstrated similar outcomes for the ADTR and RY groups. Multivariate analysis of significantly different factors that presented as covariates on Cox regression analysis to assess the survival and recurrence among AEG patients showed that age,gender,BMI,pleural effusion,time to resuming a liquid diet,lymphorrhagia and tumor-nodemetastasis stage were important prognostic factors for OS of AEG patients,whereas the selection of surgical method between ADTR and RY was shown to be a similar prognostic factor for OS of AEG patients.CONCLUSION:ADTR by jejunal interposition presents similar rates of tumor recurrence,metastasis and longterm survival compared with classical reconstruction with RY esophagojejunostomy; however,it offers considerably improved near-term quality of life,especially in terms of early recovery and decreased reflux esophagitis. Thus,ADTR is recommended as a worthwhile digestive tract reconstruction method for Siewert types Ⅱ and Ⅲ AEG.

Non-coding RNA in drug resistance of gastric cancer

Gastric cancer(GC)is the third leading cause of cancer-related mortality worldwide.The poorly prognosis and survival of GC are due to diagnose in an advanced,non-curable stage and with a limited response to chemotherapy.The acquisition of drug resistance accounts for the majority of therapy failure of chemotherapy in GC patients.Although the mechanisms of anticancer drug resistance have been broadly studied,the regulation of these mechanisms has not been completely understood.Accumulating evidence has recently highlighted the role of non-coding RNAs(ncRNAs),including long non-coding RNAs and microRNAs,in the development and maintenance of drug resistance due to their regulatory features in specific genes involved in the chemoresistant phenotype of GC.We review the literature on ncRNAs in drug resistance of GC.This review summarizes the current knowledge about the ncRNAs’characteristics,their regulation of the genes involved in chemoresistance and their potential as targeted therapies for personalized treatment in resistant GC.

Decreased expression of the long non-coding RNA HOXD-AS2 promotes gastric cancer progression by targeting HOXD8 and activating PI3K/Akt signaling pathway

BACKGROUND Long non-coding RNAs(lncRNAs) have been shown to be associated with many tumors. However, the specific mechanism of lncRNAs in the occurrence and development of gastric cancer(GC) has not been fully elucidated.AIM To explore the expression level and molecular mechanism of HOXD-AS2 in GC tissues and cells, and analyze its significance in the prognosis of GC.METHODS Real-time quantitative PCR was used to detect the expression of HOXD-AS2 in 79 pairs of GC tissues and five cell lines. The pc HOXD-AS2 plasmid vector was constructed and transfected into SGC-7901 and SNU-1 GC cells. Matrigel Transwell and wound healing assays were used to confirm the effect of HOXDAS2 on invasion and migration of GC cells. Cell counting kit-8 assay and flow cytometry were used to verify the effect of HOXD-AS2 on the proliferation, cell cycle, and apoptosis of GC cells. The relevant regulatory mechanism between HOXD-AS2 and HOXD8 and PI3K/Akt signaling pathway was verified by Western blot analysis.RESULTS The low expression of lncRNA HOXD-AS2 was associated with lymph node metastasis and tumor-node-metastasis stage in GC. In vitro functional experiments demonstrated that overexpression of HOXD-AS2 inhibited GC cell progression. Mechanistic studies revealed that HOXD-AS2 regulated the expression of its nearby gene HOXD8 and inhibited the activity of the PI3K/Akt signaling pathway.CONCLUSION These results indicate that downregulation of HOXD-AS2 significantly promotes the progression of GC cells by regulating HOXD8 expression and activating the PI3K/Akt signaling pathway. HOXD-AS2 may be a novel diagnostic biomarker and effective therapeutic target for GC.