Objective: To discuss the expression and significance of angiostatin, vascular endothelial growth factor and matrix metalloproteinase-9 in the brain tissue of diabetic rats with ischemia reperfusion. Methods: A total ...Objective: To discuss the expression and significance of angiostatin, vascular endothelial growth factor and matrix metalloproteinase-9 in the brain tissue of diabetic rats with ischemia reperfusion. Methods: A total of 60 male Wistar rats were randomly divided into the normal group, sham group, diabetic cerebral infarction group and single cerebral infarction group according to the random number table, with 15 rats in each group. The high sucrose diet and intraperitoneal injection of streptozotocin were performed for the modeling of diabetic rats, while the thread-occlusion method was employed to build the model of cerebral ischemia reperfusion. The immunohistochemical staining was performed to detect the expression of angiostatin, vascular endothelial growth factor(VEGF) and matrix metalloproteinase-9(MMP-9) in the brain tissue. Results: The expression of angiostatin after the reperfusion in the brain tissue of rats in the single cerebral infarction group and diabetic cerebral infarction group was increased 6 h after the reperfusion, reached to the peak on 1 d and then decreased gradually. The expression of angiostatin in the diabetic cerebral infarction group 6 h, 1 d, 3 d and 7 d after the reperfusion was significantly higher than that in the single cerebral infarction group(P<0.05). VEGF began to be increased 1 h after the reperfusion in the single cerebral infarction group and diabetic cerebral infarction group, reached to the peak at 6 h and then decreased gradually. The expression of VEGF in the diabetic cerebral infarction group at each time point after the reperfusion was significantly lower than that in the single cerebral infarction group(P<0.05). MMP-9 began to be be increased 1 h after the reperfusion in the single cerebral infarction group and diabetic cerebral infarction group, reached to the peak on 1 d and then decreased gradually. The expression of MMP-9 in the diabetic cerebral infarction group at each time point after the reperfusion was significantly higher than that in the single cerebral infarction group(P<0.05). Conclusions: The high glucose environment in which the diabetic cerebral infarction is occurred is to induce the formation of MMP-9 at first and then activate and increase the expression of angiostatin. Afterwards, the expression of VEGF is inhibited, resulting in the poor angiogenesis after cerebral infarction, which thus makes the injury of brain tissue after cerebral infarction even worse than the non-diabetes mellitus.展开更多
Objective: To understand the changing trajectory of quality of life(QOL) during the treatment courses of breast cancer patients during chemotherapy and to investigate the factors in each treatment course that affect Q...Objective: To understand the changing trajectory of quality of life(QOL) during the treatment courses of breast cancer patients during chemotherapy and to investigate the factors in each treatment course that affect QOL.Methods: The M.D. Anderson Symptom Inventory Scale, the Hospital Anxiety and Depression Scale(HADS), and the Functional Assessment of Cancer Therapy-Breast(FACT-B) scale were used to perform a survey on 174 breast cancer patients who received the TAC(docetaxel, Adriamycin, and cyclophosphamide) chemotherapy regimen before postoperative chemotherapy and 5-7 days after each chemotherapy course.Results: The QOL scores of the breast cancer patients were the lowest before the postoperative chemotherapy(81.2 ± 19.6) and the highest after the second chemotherapy course(94.5 ± 14.4). After the fourth and fifth chemotherapy courses, the scores were much lower again, with values of 82.7 ± 13.9and 82.6 ± 13.1, respectively. The scores improved again after the sixth chemotherapy course(93.9 ± 18.7). Furthermore, each treatment course had different related symptoms that affected the QOL of the patients.Conclusions: More attention should be paid to the changing trajectory of QOL of patients in all treatment courses and to the influence of treatment-related symptoms on the QOL of patients; moreover, interventions should be adopted by medical care personnel to increase QOL in cancer patients.展开更多
Objective To investigate the impact of microvascular obstruction(MVO)on the global and regional myocardial function by cardiac magnetic resonance feature-tracking(CMR-FT)in ST-segment-elevation myocardial infarction(S...Objective To investigate the impact of microvascular obstruction(MVO)on the global and regional myocardial function by cardiac magnetic resonance feature-tracking(CMR-FT)in ST-segment-elevation myocardial infarction(STEMI)patients after percutaneous coronary intervention.Methods Consecutive acute STEMI patients who underwent cardiac magnetic resonance imaging 1-7 days after successful reperfusion by percutaneous coronary intervention treatment were included in this retrospective study.Based on the presence or absence of MVO on late gadolinium enhancement images,patients were divided into groups with MVO and without MVO.The infarct zone,adjacent zone,and remote zone were determined based on a myocardial 16-segment model.The radial strain(RS),circumferential strain(CS),and longitudinal strain(LS)of the global left ventricle(LV)and the infarct,adjacent,and remote zones were measured by CMRFT from cine images and compared between patients with and without MVO using independent-samples t-test.Logistic regression analysis was used to assess the association of MVO with the impaired LV function.Results A total of 157 STEMI patients(mean age 56.66±11.38 years)were enrolled.MVO was detected in 37.58%(59/157)of STEMI patients,and the mean size of MVO was 3.00±3.76 mL.Compared with patients without MVO(n=98),the MVO group had significantly reduced LV global RS(t=-4.30,P<0.001),global CS(t=4.99,P<0.001),and global LS(t=3.51,P=0.001).The RS and CS of the infarct zone in patients with MVO were significantly reduced(t=-3.38,P=0.001;t=2.64,P=0.01;respectively)and the infarct size was significantly larger(t=8.37,P<0.001)than that of patients without MVO.The presence of LV MVO[OR=4.10,95%CI:2.05-8.19,P<0.001]and its size[OR=1.38,95%CI:1.10-1.72,P=0.01],along with the heart rate and LV infarct size were significantly associated with impaired LV global CS in univariable Logistic regression analysis,while only heart rate(OR=1.08,95%CI:1.03-1.13,P=0.001)and LV infarct size(OR=1.10,95%CI:1.03-1.16,P=0.003)were independent influencing factors for the impaired LV global CS in multivariable Logistic regression analysis.Conclusion The infarct size was larger in STEMI patients with MVO,and MVO deteriorates the global and regional LV myocardial function.展开更多
Objective: To investigate the associations between the different breast cancer subtypes and survival in Chinese women with operable primary breast cancer. Methods: A total of 1538 Chinese women with operable primary b...Objective: To investigate the associations between the different breast cancer subtypes and survival in Chinese women with operable primary breast cancer. Methods: A total of 1538 Chinese women with operable primary breast cancer were analyzed in this study, the median follow-up was 77 months. Estrogen receptor (ER), progesterone receptor (PR), and HER2 status were available for these patients. Results: Luminal A (ER+ and/or PR+, HER2-) had a favorable disease-free survival (DFS) and overall survival (OS) compared with other subtypes in the entire cohort. Using the luminal A as a reference, among the patients with lymph node positive disease, HER2+ (ER-, PR-, HER2+) had the worst DFS (hazard ratio, HR=1.80, 95% CI 1.11 to 2.91, P=0.017) and luminal B (ER+ and/or PR+, HER2+) had the worst OS (HR=2.27, 95% CI 1.50 to 3.45, P<0.001); among the patients with lymph node negative disease, triple-negative (ER-, PR-, HER2-) had the worst DFS (HR=2.21, 95% CI 1.43 to 3.41, P<0.001), whereas no significant difference in DFS between HER2+ and luminal B or luminal A was observed. Conclusion: As compared with luminal A, luminal B and HER2+ have the worst survival in patients with lymph node positive disease, but this is not the case in patients with lymph node negative disease; triple-negative subtype has a worse survival in both lymph node positive and lymph node negative patients.展开更多
目的探讨沉默信息调节因子1(SIRT1)在异烟肼致人肝细胞损伤中的作用。方法培养人正常肝细胞HL-7702,实验分为6组:空白对照组、异烟肼组、异烟肼+SIRT1激动剂组、SIRT1激动剂对照组、异烟肼+SIRT1抑制剂组、SIRT1抑制剂对照组。取各组细...目的探讨沉默信息调节因子1(SIRT1)在异烟肼致人肝细胞损伤中的作用。方法培养人正常肝细胞HL-7702,实验分为6组:空白对照组、异烟肼组、异烟肼+SIRT1激动剂组、SIRT1激动剂对照组、异烟肼+SIRT1抑制剂组、SIRT1抑制剂对照组。取各组细胞上清液测定丙氨酸转氨酶(ALT)、天门冬氨酸转氨酶(AST)含量;实时荧光定量聚合酶链反应(q RT-PCR)检测肝细胞SIRT1、NF-k B p65 mRNA表达水平;酶联免疫吸附法(ELISA)检测SIRT1、核转录因子k B(NF-k B p65)、白细胞介素6(IL-6)、肿瘤坏死因子α(TNF-α)蛋白表达水平。结果与空白对照组比较,异烟肼组细胞SIRT1的mRNA和蛋白表达下降(P<0.05),其下游靶基因NF-k B p65的mRNA和蛋白表达升高(P<0.05),炎症因子IL-6、TNF-α蛋白表达水平升高(P<0.05)。加入SIRT1激动剂可减轻异烟肼引起的炎症反应,加入SIRT1抑制剂可使NF-k B p65、IL-6、TNF-α表达水平进一步升高从而加重细胞的炎症损伤。结论异烟肼诱导肝细胞损伤过程中,降低SIRT1水平,增加炎症因子的表达。SIRT1的激活可以通过降低NF-k B p65表达进而减轻肝细胞损伤的发生。展开更多
CEREBRAL aspergillosis is a rare and severe disorder with rapid progressive pathogenesis,and commonly seen in immunocompromised patients.1Typical cerebral aspergillosis presents abscess with ring enhancement or cortic...CEREBRAL aspergillosis is a rare and severe disorder with rapid progressive pathogenesis,and commonly seen in immunocompromised patients.1Typical cerebral aspergillosis presents abscess with ring enhancement or cortical or subcortical infactions on magnetic resonance(MR)images.In this communication,we describe a rare cerebral aspergillosis with relative characteristic MR imaging findings.展开更多
The present study focuses on investigating the microstructural evolutions and mechanical properties of energetic Al_(1)(TiZrNbTaMoCr)_(15) refractory high-entropy alloys with the different heat treatments at low Al co...The present study focuses on investigating the microstructural evolutions and mechanical properties of energetic Al_(1)(TiZrNbTaMoCr)_(15) refractory high-entropy alloys with the different heat treatments at low Al content state. It is found that even with a reduction in the Al content, the strength of these alloys remains unaffected at room temperature and high temperature, while the plasticity improves significantly. In particular, the coherent BCC/B_(2) microstructure with needle-like B_(2) nanoprecipitates dispersed into the BCC matrix is formed in 873 K-aged Al_(1)Ti_(6)Zr_(2)Nb_(3)Ta_(3)Mo_(0.5)Cr_(0.5) alloy. Therefore, this alloy exhibits the highest compression yield strength (σ_(YS) = 1333 and 717 MPa) at room temperature and 1073 K, respectively. After 973 K-aged, the coherent BCC/B_(2) microstructure underwent destabilization, and the B_(2) phase transforms into the brittle Zr5Al3 phase which then coarsens and dominates the microstructure of S3-AlTa_(3) alloy after 1073 K-aged. Moreover, these current alloys exhibit exceptionally high theoretical exothermic enthalpy (ΔH), surpassing 11606 J·g^(−1), which highlights their significant potential as innovative high-performance energetic structural materials.展开更多
The influence of pre-deformation on aging precipitates of three near peak-aged Al–Cu–Li alloys,1460 alloy with a low Cu/Li ratio(1.46),2050 alloy with a high Cu/Li ratio(4.51) and 2A96 alloy with a medium Cu/Li rati...The influence of pre-deformation on aging precipitates of three near peak-aged Al–Cu–Li alloys,1460 alloy with a low Cu/Li ratio(1.46),2050 alloy with a high Cu/Li ratio(4.51) and 2A96 alloy with a medium Cu/Li ratio(2.97),was investigated.The strength of the aged alloys is enhanced by the pre-deformation.The effectiveness of pre-deformation on precipitates is dependent on the alloy's composition.With increasing the pre-deformation,the population density of T1(Al_2Cu Li) precipitates increases in all three Al–Cu–Li alloys and their diameter decreases in 2050 and 2A96 alloys,and the greatest effectiveness is observed in 2A96 alloy.The pre-deformation also increases the population density of θ'(Al_2Cu)precipitates and decreases their diameter in 2050 and 2A96 Al–Li alloys,but the effectiveness is smaller compared to that on T1 precipitates.In 1460 alloy subjected to two-step aging at 130 °C for 20 h followed by 160 °C for 12 h,the main precipitates are δ'(Al_3Li).At 2%–6% pre-deformation,GP-I zones form and pre-deformation displays little influence.Eight percentage pre-deformation promotes θ''/θ' precipitation and increases their population density.展开更多
The microstructure evolution and the corrosion feature of Al–x Cu– y Li–Mg alloys( x : y = 0.44, 1.65 and 4.2) were systematically investigated under the same artificial aging conditions. The relationships between ...The microstructure evolution and the corrosion feature of Al–x Cu– y Li–Mg alloys( x : y = 0.44, 1.65 and 4.2) were systematically investigated under the same artificial aging conditions. The relationships between types of precipitates and mechanical performance, as well as electrochemical behaviors, were discussed. Our results show that different types of precipitates can be obtained in alloys with different Cu/Li mass ratios, which significantly influences the mechanical performance of the alloys and substantial corrosion behaviors. Specifically, the analogous corrosion evolution in the aging Al– x Cu– y Li–Mg alloys was first ascertained to be derived from the growth mechanism of the precipitates at the grain boundary(GB). Moreover, a small number of GB precipitates can be obtained in the aged alloy with the lowest Cu/Li mass ratio, thereby resulting in the largest intergranular corrosion resistance. A higher proportion of the GB T1 phase in the continuous precipitates induces higher corrosion sensitivity in alloy with a high Cu/Li mass ratio.展开更多
The micros tructural evolution and mechanical properties of a new Al-3.8 Cu-1.2 Li-0.4 Mg-0.4 Zn-0.4 Ag-0.3 Mn-X alloy treated at different solution temperatures were investigated.The grain size was measured in optica...The micros tructural evolution and mechanical properties of a new Al-3.8 Cu-1.2 Li-0.4 Mg-0.4 Zn-0.4 Ag-0.3 Mn-X alloy treated at different solution temperatures were investigated.The grain size was measured in optical micrograph(OM).The residual particles and the major precipitates were identified by electron probe microanalysis(EPMA),scanning electron microscopy(SEM) and transmission electron microscope(TEM),respectively.The results show that the peak strength appears at 530℃/1 h+T6(165℃/20 h) and the values are 566.2 MPa(tensile strength) and 538.2 MPa(yield strength) with the elongation of 6.5 %.The strength of the alloy increases rapidly with the amount of the precipitates T1 and θ’ increasing when the solution temperature is530℃.The increase in density of precipitates is resulted from the residual particles Al2 Cu,and particles enriched with Cu,Mg,Zr and Ag dissolve into matrix gradually with the solution temperature increasing.Finally,the number of precipitates decreases and part of the grain boundary weakens with a further increase in solution temperature from 540 to 550℃,leading to a decline of strength.展开更多
High-entropy alloys(HEAs)are an emerging and rapidly developing family of alloys with appealing properties such as lightweight HEAs with excellent mechanical properties.In this study,to obtain lightweight HEAs with ex...High-entropy alloys(HEAs)are an emerging and rapidly developing family of alloys with appealing properties such as lightweight HEAs with excellent mechanical properties.In this study,to obtain lightweight HEAs with exceptional hardness,we prepared AlCrTiV_(0.5)Cu_(x)(x=0,0.2,0.4,0.6,0.8 and 1.0,denoted as Cu_(0),Cu_(0.2),Cu_(0.4),Cu_(0.6),Cu_(0.8) and Cu_(1.0) alloys,respectively)HEAs and analyzed their microstructure and hardness.展开更多
基金Project(2013JSJJ0001)supported by the Teachers’ Research Fund,Central South University,ChinaProject supported by the Nonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Center,China
基金supported by Shandong Science and Technology Development Plan Project(No.Y2006C02)
文摘Objective: To discuss the expression and significance of angiostatin, vascular endothelial growth factor and matrix metalloproteinase-9 in the brain tissue of diabetic rats with ischemia reperfusion. Methods: A total of 60 male Wistar rats were randomly divided into the normal group, sham group, diabetic cerebral infarction group and single cerebral infarction group according to the random number table, with 15 rats in each group. The high sucrose diet and intraperitoneal injection of streptozotocin were performed for the modeling of diabetic rats, while the thread-occlusion method was employed to build the model of cerebral ischemia reperfusion. The immunohistochemical staining was performed to detect the expression of angiostatin, vascular endothelial growth factor(VEGF) and matrix metalloproteinase-9(MMP-9) in the brain tissue. Results: The expression of angiostatin after the reperfusion in the brain tissue of rats in the single cerebral infarction group and diabetic cerebral infarction group was increased 6 h after the reperfusion, reached to the peak on 1 d and then decreased gradually. The expression of angiostatin in the diabetic cerebral infarction group 6 h, 1 d, 3 d and 7 d after the reperfusion was significantly higher than that in the single cerebral infarction group(P<0.05). VEGF began to be increased 1 h after the reperfusion in the single cerebral infarction group and diabetic cerebral infarction group, reached to the peak at 6 h and then decreased gradually. The expression of VEGF in the diabetic cerebral infarction group at each time point after the reperfusion was significantly lower than that in the single cerebral infarction group(P<0.05). MMP-9 began to be be increased 1 h after the reperfusion in the single cerebral infarction group and diabetic cerebral infarction group, reached to the peak on 1 d and then decreased gradually. The expression of MMP-9 in the diabetic cerebral infarction group at each time point after the reperfusion was significantly higher than that in the single cerebral infarction group(P<0.05). Conclusions: The high glucose environment in which the diabetic cerebral infarction is occurred is to induce the formation of MMP-9 at first and then activate and increase the expression of angiostatin. Afterwards, the expression of VEGF is inhibited, resulting in the poor angiogenesis after cerebral infarction, which thus makes the injury of brain tissue after cerebral infarction even worse than the non-diabetes mellitus.
基金supported by a project of scientific research of the Affiliated Hospital of Luzhou Medical College(No.14039)
文摘Objective: To understand the changing trajectory of quality of life(QOL) during the treatment courses of breast cancer patients during chemotherapy and to investigate the factors in each treatment course that affect QOL.Methods: The M.D. Anderson Symptom Inventory Scale, the Hospital Anxiety and Depression Scale(HADS), and the Functional Assessment of Cancer Therapy-Breast(FACT-B) scale were used to perform a survey on 174 breast cancer patients who received the TAC(docetaxel, Adriamycin, and cyclophosphamide) chemotherapy regimen before postoperative chemotherapy and 5-7 days after each chemotherapy course.Results: The QOL scores of the breast cancer patients were the lowest before the postoperative chemotherapy(81.2 ± 19.6) and the highest after the second chemotherapy course(94.5 ± 14.4). After the fourth and fifth chemotherapy courses, the scores were much lower again, with values of 82.7 ± 13.9and 82.6 ± 13.1, respectively. The scores improved again after the sixth chemotherapy course(93.9 ± 18.7). Furthermore, each treatment course had different related symptoms that affected the QOL of the patients.Conclusions: More attention should be paid to the changing trajectory of QOL of patients in all treatment courses and to the influence of treatment-related symptoms on the QOL of patients; moreover, interventions should be adopted by medical care personnel to increase QOL in cancer patients.
文摘Objective To investigate the impact of microvascular obstruction(MVO)on the global and regional myocardial function by cardiac magnetic resonance feature-tracking(CMR-FT)in ST-segment-elevation myocardial infarction(STEMI)patients after percutaneous coronary intervention.Methods Consecutive acute STEMI patients who underwent cardiac magnetic resonance imaging 1-7 days after successful reperfusion by percutaneous coronary intervention treatment were included in this retrospective study.Based on the presence or absence of MVO on late gadolinium enhancement images,patients were divided into groups with MVO and without MVO.The infarct zone,adjacent zone,and remote zone were determined based on a myocardial 16-segment model.The radial strain(RS),circumferential strain(CS),and longitudinal strain(LS)of the global left ventricle(LV)and the infarct,adjacent,and remote zones were measured by CMRFT from cine images and compared between patients with and without MVO using independent-samples t-test.Logistic regression analysis was used to assess the association of MVO with the impaired LV function.Results A total of 157 STEMI patients(mean age 56.66±11.38 years)were enrolled.MVO was detected in 37.58%(59/157)of STEMI patients,and the mean size of MVO was 3.00±3.76 mL.Compared with patients without MVO(n=98),the MVO group had significantly reduced LV global RS(t=-4.30,P<0.001),global CS(t=4.99,P<0.001),and global LS(t=3.51,P=0.001).The RS and CS of the infarct zone in patients with MVO were significantly reduced(t=-3.38,P=0.001;t=2.64,P=0.01;respectively)and the infarct size was significantly larger(t=8.37,P<0.001)than that of patients without MVO.The presence of LV MVO[OR=4.10,95%CI:2.05-8.19,P<0.001]and its size[OR=1.38,95%CI:1.10-1.72,P=0.01],along with the heart rate and LV infarct size were significantly associated with impaired LV global CS in univariable Logistic regression analysis,while only heart rate(OR=1.08,95%CI:1.03-1.13,P=0.001)and LV infarct size(OR=1.10,95%CI:1.03-1.16,P=0.003)were independent influencing factors for the impaired LV global CS in multivariable Logistic regression analysis.Conclusion The infarct size was larger in STEMI patients with MVO,and MVO deteriorates the global and regional LV myocardial function.
基金supported by grants from the Program fro Breast Cancer Tissue Bank of Beijingthe National Natural Science Foundation of China (No.30973436)
文摘Objective: To investigate the associations between the different breast cancer subtypes and survival in Chinese women with operable primary breast cancer. Methods: A total of 1538 Chinese women with operable primary breast cancer were analyzed in this study, the median follow-up was 77 months. Estrogen receptor (ER), progesterone receptor (PR), and HER2 status were available for these patients. Results: Luminal A (ER+ and/or PR+, HER2-) had a favorable disease-free survival (DFS) and overall survival (OS) compared with other subtypes in the entire cohort. Using the luminal A as a reference, among the patients with lymph node positive disease, HER2+ (ER-, PR-, HER2+) had the worst DFS (hazard ratio, HR=1.80, 95% CI 1.11 to 2.91, P=0.017) and luminal B (ER+ and/or PR+, HER2+) had the worst OS (HR=2.27, 95% CI 1.50 to 3.45, P<0.001); among the patients with lymph node negative disease, triple-negative (ER-, PR-, HER2-) had the worst DFS (HR=2.21, 95% CI 1.43 to 3.41, P<0.001), whereas no significant difference in DFS between HER2+ and luminal B or luminal A was observed. Conclusion: As compared with luminal A, luminal B and HER2+ have the worst survival in patients with lymph node positive disease, but this is not the case in patients with lymph node negative disease; triple-negative subtype has a worse survival in both lymph node positive and lymph node negative patients.
文摘目的探讨沉默信息调节因子1(SIRT1)在异烟肼致人肝细胞损伤中的作用。方法培养人正常肝细胞HL-7702,实验分为6组:空白对照组、异烟肼组、异烟肼+SIRT1激动剂组、SIRT1激动剂对照组、异烟肼+SIRT1抑制剂组、SIRT1抑制剂对照组。取各组细胞上清液测定丙氨酸转氨酶(ALT)、天门冬氨酸转氨酶(AST)含量;实时荧光定量聚合酶链反应(q RT-PCR)检测肝细胞SIRT1、NF-k B p65 mRNA表达水平;酶联免疫吸附法(ELISA)检测SIRT1、核转录因子k B(NF-k B p65)、白细胞介素6(IL-6)、肿瘤坏死因子α(TNF-α)蛋白表达水平。结果与空白对照组比较,异烟肼组细胞SIRT1的mRNA和蛋白表达下降(P<0.05),其下游靶基因NF-k B p65的mRNA和蛋白表达升高(P<0.05),炎症因子IL-6、TNF-α蛋白表达水平升高(P<0.05)。加入SIRT1激动剂可减轻异烟肼引起的炎症反应,加入SIRT1抑制剂可使NF-k B p65、IL-6、TNF-α表达水平进一步升高从而加重细胞的炎症损伤。结论异烟肼诱导肝细胞损伤过程中,降低SIRT1水平,增加炎症因子的表达。SIRT1的激活可以通过降低NF-k B p65表达进而减轻肝细胞损伤的发生。
文摘CEREBRAL aspergillosis is a rare and severe disorder with rapid progressive pathogenesis,and commonly seen in immunocompromised patients.1Typical cerebral aspergillosis presents abscess with ring enhancement or cortical or subcortical infactions on magnetic resonance(MR)images.In this communication,we describe a rare cerebral aspergillosis with relative characteristic MR imaging findings.
基金supported by the Key Basic Research Project of National Foundation Strengthening Program(No.2021-JCJQ-ZD-030-12)the National Natural Science Foundation of China(No.52171152).
文摘The present study focuses on investigating the microstructural evolutions and mechanical properties of energetic Al_(1)(TiZrNbTaMoCr)_(15) refractory high-entropy alloys with the different heat treatments at low Al content state. It is found that even with a reduction in the Al content, the strength of these alloys remains unaffected at room temperature and high temperature, while the plasticity improves significantly. In particular, the coherent BCC/B_(2) microstructure with needle-like B_(2) nanoprecipitates dispersed into the BCC matrix is formed in 873 K-aged Al_(1)Ti_(6)Zr_(2)Nb_(3)Ta_(3)Mo_(0.5)Cr_(0.5) alloy. Therefore, this alloy exhibits the highest compression yield strength (σ_(YS) = 1333 and 717 MPa) at room temperature and 1073 K, respectively. After 973 K-aged, the coherent BCC/B_(2) microstructure underwent destabilization, and the B_(2) phase transforms into the brittle Zr5Al3 phase which then coarsens and dominates the microstructure of S3-AlTa_(3) alloy after 1073 K-aged. Moreover, these current alloys exhibit exceptionally high theoretical exothermic enthalpy (ΔH), surpassing 11606 J·g^(−1), which highlights their significant potential as innovative high-performance energetic structural materials.
基金the National High Technology Research and Development Program of China(No.2013AA032401)Teacher’s Research Foundation of Central South University(No.2013JSJJ 001) for the financial supportNonferrous Metal Oriented Advanced Structural Materials and Manufacturing Cooperative Innovation Centre
文摘The influence of pre-deformation on aging precipitates of three near peak-aged Al–Cu–Li alloys,1460 alloy with a low Cu/Li ratio(1.46),2050 alloy with a high Cu/Li ratio(4.51) and 2A96 alloy with a medium Cu/Li ratio(2.97),was investigated.The strength of the aged alloys is enhanced by the pre-deformation.The effectiveness of pre-deformation on precipitates is dependent on the alloy's composition.With increasing the pre-deformation,the population density of T1(Al_2Cu Li) precipitates increases in all three Al–Cu–Li alloys and their diameter decreases in 2050 and 2A96 alloys,and the greatest effectiveness is observed in 2A96 alloy.The pre-deformation also increases the population density of θ'(Al_2Cu)precipitates and decreases their diameter in 2050 and 2A96 Al–Li alloys,but the effectiveness is smaller compared to that on T1 precipitates.In 1460 alloy subjected to two-step aging at 130 °C for 20 h followed by 160 °C for 12 h,the main precipitates are δ'(Al_3Li).At 2%–6% pre-deformation,GP-I zones form and pre-deformation displays little influence.Eight percentage pre-deformation promotes θ''/θ' precipitation and increases their population density.
基金Postdoctoral Research Station of Mechanical Engineering of school of Mechanical and Electrical Engineering of Central South Universityfinancially supported by the National Foundation of China(No.TDZX-17-005-1)。
文摘The microstructure evolution and the corrosion feature of Al–x Cu– y Li–Mg alloys( x : y = 0.44, 1.65 and 4.2) were systematically investigated under the same artificial aging conditions. The relationships between types of precipitates and mechanical performance, as well as electrochemical behaviors, were discussed. Our results show that different types of precipitates can be obtained in alloys with different Cu/Li mass ratios, which significantly influences the mechanical performance of the alloys and substantial corrosion behaviors. Specifically, the analogous corrosion evolution in the aging Al– x Cu– y Li–Mg alloys was first ascertained to be derived from the growth mechanism of the precipitates at the grain boundary(GB). Moreover, a small number of GB precipitates can be obtained in the aged alloy with the lowest Cu/Li mass ratio, thereby resulting in the largest intergranular corrosion resistance. A higher proportion of the GB T1 phase in the continuous precipitates induces higher corrosion sensitivity in alloy with a high Cu/Li mass ratio.
基金financially supported by the National High-Tech Research and Development Program of China(No.2013AA032401)。
文摘The micros tructural evolution and mechanical properties of a new Al-3.8 Cu-1.2 Li-0.4 Mg-0.4 Zn-0.4 Ag-0.3 Mn-X alloy treated at different solution temperatures were investigated.The grain size was measured in optical micrograph(OM).The residual particles and the major precipitates were identified by electron probe microanalysis(EPMA),scanning electron microscopy(SEM) and transmission electron microscope(TEM),respectively.The results show that the peak strength appears at 530℃/1 h+T6(165℃/20 h) and the values are 566.2 MPa(tensile strength) and 538.2 MPa(yield strength) with the elongation of 6.5 %.The strength of the alloy increases rapidly with the amount of the precipitates T1 and θ’ increasing when the solution temperature is530℃.The increase in density of precipitates is resulted from the residual particles Al2 Cu,and particles enriched with Cu,Mg,Zr and Ag dissolve into matrix gradually with the solution temperature increasing.Finally,the number of precipitates decreases and part of the grain boundary weakens with a further increase in solution temperature from 540 to 550℃,leading to a decline of strength.
基金financially supported by the National Natural Science Foundation of China (No.51871129)the Open Funding of State Key Laboratory for Advanced Metals and Materials (No.2020-Z10)
文摘High-entropy alloys(HEAs)are an emerging and rapidly developing family of alloys with appealing properties such as lightweight HEAs with excellent mechanical properties.In this study,to obtain lightweight HEAs with exceptional hardness,we prepared AlCrTiV_(0.5)Cu_(x)(x=0,0.2,0.4,0.6,0.8 and 1.0,denoted as Cu_(0),Cu_(0.2),Cu_(0.4),Cu_(0.6),Cu_(0.8) and Cu_(1.0) alloys,respectively)HEAs and analyzed their microstructure and hardness.
