Objective Lindqvist-type polyoxometalates(POMs)exhibit potential antitumor activities.This study aimed to examine the effects of Lindqvist-type POMs against breast cancer and the underlying mechanism.Methods Using dif...Objective Lindqvist-type polyoxometalates(POMs)exhibit potential antitumor activities.This study aimed to examine the effects of Lindqvist-type POMs against breast cancer and the underlying mechanism.Methods Using different cancer cell lines,the present study evaluated the antitumor activities of POM analogues that were modified at the body skeleton based on molybdenum-vanadium-centered negative oxygen ion polycondensations with different side strains.Cell colony formation assay,autophagy detection,mitochondrial observation,qRT-PCR,Western blotting,and animal model were used to evaluate the antitumor activities of POMs against breast cancer cells and the related mechanism.Results MO-4,a Lindqvist-type POM linking a proline at its side strain,was selected for subsequent experiments due to its low half maximal inhibitory concentration in the inhibition of proliferation of breast cancer cells.It was found that MO-4 induced the apoptosis of multiple types of breast cancer cells.Mechanistically,MO-4 activated intracellular mitophagy by elevating mitochondrial reactive oxygen species(ROS)levels and resulting in apoptosis.In vivo,breast tumor growth and distant metastasis were significantly reduced following MO-4 treatment.Conclusion Collectively,the results of the present study demonstrated that the novel Lindqvist-type POM MO-4 may exhibit potential in the treatment of breast cancer.展开更多
BACKGROUND Hepatocellular carcinoma(HCC)ranks second in terms of cancer mortality worldwide.Molecular magnetic resonance imaging(MRI)targeting HCC biomarkers such as alpha-fetoprotein(AFP)or glypican-3(GPC3)offers new...BACKGROUND Hepatocellular carcinoma(HCC)ranks second in terms of cancer mortality worldwide.Molecular magnetic resonance imaging(MRI)targeting HCC biomarkers such as alpha-fetoprotein(AFP)or glypican-3(GPC3)offers new strategies to enhance specificity and help early diagnosis of HCC.However,the existing iron oxide nanoparticle-based MR molecular probes singly target AFP or GPC3,which may hinder their efficiency to detect heterogeneous micro malignant HCC tumors<1 cm(MHCC).We hypothesized that the strategy of double antibody-conjugated iron oxide nanoparticles which simultaneously target AFP and GPC3 antigens may potentially be used to overcome the tumor heterogeneity and enhance the detection rate for MRI-based MHCC diagnosis.AIM To synthesize an AFP/GPC3 double antibody-labeled iron oxide MRI molecular probe and to assess its impact on MRI specificity and sensitivity at the cellular level.METHODS A double antigen-targeted MRI probe for MHCC anti-AFP-USPIO-anti-GPC3(UAG)was developed by simultaneously conjugating AFP andGPC3 antibodies to a 5 nm ultra-small superparamagnetic iron oxide nanoparticle(USPIO).At the same time,the singly labeled probes of anti-AFP-USPIO(UA)and anti-GPC3-USPIO(UG)and non-targeted USPIO(U)were also prepared for comparison.The physical characterization including morphology(transmission electron microscopy),hydrodynamic size,and zeta potential(dynamic light scattering)was conducted for each of the probes.The antigen targeting and MRI ability for these four kinds of USPIO probes were studied in the GPC3-expressing murine hepatoma cell line Hepa1-6/GPC3.First,AFP and GPC3 antigen expression in Hepa1-6/GPC3 cells was confirmed by flow cytometry and immunocytochemistry.Then,the cellular uptake of USPIO probes was investigated by Prussian blue staining assay and in vitro MRI(T2-weighted and T2-map)with a 3.0 Tesla clinical MR scanner.RESULTS Our data showed that the double antibody-conjugated probe UAG had the best specificity in targeting Hepa1-6/GPC3 cells expressing AFP and GPC3 antigens compared with single antibody-conjugated and unconjugated USPIO probes.The iron Prussian blue staining and quantitative T2-map MRI analysis showed that,compared with UA,UG,and U,the uptake of double antigen-targeted UAG probe demonstrated a 23.3%(vs UA),15.4%(vs UG),and 57.3%(vs U)increased Prussian stained cell percentage and a 14.93%(vs UA),9.38%(vs UG),and 15.3%(vs U)reduction of T2 relaxation time,respectively.Such bi-specific probe might have the potential to overcome tumor heterogeneity.Meanwhile,the coupling of two antibodies did not influence the magnetic performance of USPIO,and the relatively small hydrodynamic size(59.60±1.87 nm)of double antibodyconjugated USPIO probe makes it a viable candidate for use in MHCC MRI in vivo,as they are slowly phagocytosed by macrophages.CONCLUSION The bi-specific probe presents enhanced targeting efficiency and MRI sensitivity to HCC cells than singly-or non-targeted USPIO,paving the way for in vivo translation to further evaluate its clinical potential.展开更多
Introduction:Breast cancer is a leading tumor with a high mortality in women.This study examined the spatio-temporal distribution of the incidence of female breast cancer in Shenzhen between 2007 and 2012.Methods:The ...Introduction:Breast cancer is a leading tumor with a high mortality in women.This study examined the spatio-temporal distribution of the incidence of female breast cancer in Shenzhen between 2007 and 2012.Methods:The data on breast cancer incidence were obtained from the Shenzhen Cancer Registry System.To describe the temporal trend,the average annual percentage change(AAPC) was analyzed using a pinpoint regression model.Spatial autocorrelation and a retrospective spatio-temporal scan approach were used to detect the spatio-temporal cluster distribution of breast cancer cases.Results:Breast cancer ranked first among different types of cancer in women in Shenzhen between 2007 and 2012 with a crude incidence of 20.0/100,000 population.The age-standardized rate according to the world standard population was 21.1/100,000 in 2012,with an AAPC of 11.3%.The spatial autocorrelation analysis showed a spatial correlation characterized by the presence of a hotspot in south-central Shenzhen,which included the eastern part of Luohu District(Donghu and Liantang Streets) and Yantian District(Shatoujiao,Haishan,and Yantian Streets).Five spatio-temporal cluster areas were detected between 2010 and 2012,one of which was a Class 1 cluster located in southwestern Shenzhen in 2010,which included Yuehai,Nantou,Shahe,Shekou,and Nanshan Streets in Nanshan District with an incidence of 54.1/100,000 and a relative risk of 2.41;the other four were Class 2 clusters located in Yantian,Luohu,Futian,and Longhua Districts with a relative risk ranging from 1.70 to 3.25.Conclusions:This study revealed the spatio-temporal cluster pattern for the incidence of female breast cancer in Shenzhen,which will be useful for a better allocation of health resources in Shenzhen.展开更多
To determine the modifying agents for Al-7Si alloys, microstructure observation and mixing enthalpy analysis using Miedema model for Al-7Si alloy with additions of different rare earth elements were performed, and the...To determine the modifying agents for Al-7Si alloys, microstructure observation and mixing enthalpy analysis using Miedema model for Al-7Si alloy with additions of different rare earth elements were performed, and the effects of rare earth elements on the modifica-tion of eutectic silicon morphology were investigated. The results of mixing enthalpy analysis show that these four rare earth elements, La, Sm, Pr, and Ce, which have the large negative mixing enthalpies with Si, can be selected as modifying agents for eutectic silicon morphology. The element with the largest negative mixing enthalpy is Ce. Furthermore, the microstructures indicate that these four elements can effec-tively modify the eutectic （α）Al-Si crystals in Al-7Si alloy, and the most effective one is also Ce. Differential scanning calorimetry （DSC） results show that the eutectic temperature depressions due to the additions of modifying agents are the important reasons for the modification of eutectic （α）Al-Si crystals.展开更多
The mechanical properties of Al-Cu-Mn casting alloy mainly depend on the morphology, distribution, size, and number ofθ′（Al2Cu） precipitates. In this study, we have analyzed the effect of rare earth samarium （Sm...The mechanical properties of Al-Cu-Mn casting alloy mainly depend on the morphology, distribution, size, and number ofθ′（Al2Cu） precipitates. In this study, we have analyzed the effect of rare earth samarium （Sm） addition on the kinetics of precipitation in the Al-Cu-Mn casting alloy by using differential scanning calorimetry （DSC） and high-resolution transmission electron microscopy. Thermal ef-fect peaks that are attributed to the formation and the dissolution of Guinier-Preston （GP） zone andθ′phase were identified from the DSC curves. The activation energy ofθ′formation was calculated by using both the Kissinger method and the analytical model, and the corre-sponding results were compared. Results suggest that the activation energy ofθ′formation in Al-Cu-Mn alloy is dramatically higher than that in Al-Cu-Mn-Sm alloy. Accordingly, it is concluded that the addition of rare earth Sm decreases the activation energy ofθ′formation and promotes the formation ofθ′precipitates.展开更多
The microstructural characteristics and microhardness of nanostructured Al-4.6Cu-Mn ribbons produced by melt spinning were investigated using field-emission gun scanning electron microscopy, transmission electron micr...The microstructural characteristics and microhardness of nanostructured Al-4.6Cu-Mn ribbons produced by melt spinning were investigated using field-emission gun scanning electron microscopy, transmission electron microscopy, and hardness testing, and the results were compared to those of similar ribbons manufactured by direct-chill casting. It is shown that the nanostructure of the as-melt-spun ribbons consists of α-Al dendrites with a secondary dendrite arm spacing of approximately 0.55-0.80 μm and ultrafine eutectic crystals of a nanosized scale of approximately 100-200 nm on dendritic boundaries. The solidification time and cooling rate of 46-μm-thick ribbons were estimated to be 1.3 × 10-6 s and 4.04 × 106 K·s-1, respectively. At an aging temperature of 190°C, the coherent θ″ phase in aged ribbons gradually transforms into nanoscale θ′-phase platelets as the aging time is extended from 2 to 8 h; the rod-like morphology of the T(Al20Cu2Mn3) dispersoid with 120-160-nm diameter also forms, which results in peak aging hardness. The precipitation behaviors of aged ribbons cannot be changed at the high cooling rates of as-cast ribbons. However, a finer and more uniformly distributed microstructure and a supersaturated solid solution at a high cooling rate can shorten the time required to obtain a certain aging hardness before peak hardness.展开更多
The present study focused on the formation and crystallographic orientation of twinned dendrites coexisting with equiaxed grains in unidirectional solidification of Al-32%Zn(mass fraction)alloy.The morphology was inve...The present study focused on the formation and crystallographic orientation of twinned dendrites coexisting with equiaxed grains in unidirectional solidification of Al-32%Zn(mass fraction)alloy.The morphology was investigated by optical metallograph and electron back-scattered diffraction technique.Results showed that the macrostructure of the alloy exhibited a typical feathery and fan-like structure while the microstructures were elongated lamellas,which were separated by coherent and incoherent twin boundaries.Both the primary trunk and all lateral arms of twinned dendrites grew along〈110〉directions,unlike regular〈100〉α(Al)dendrites.The facet growth of crystals at solid/liquid interface was responsible for the origin of twinned dendrites during the weak local convection,and high thermal gradient and medium solidification velocity had significant contribution to the formation of twinned dendrites.The formation mechanism of twinned dendrites which consisted of three multiplication ways of new twin boundaries formation and one way of dendrite evolution in twin plane was shown schematically.展开更多
Texture evolution in extruded and hot-rolled Al-Mg-Li aeronautical alloys during in-situ tension was investigated by using elec-tron backscattered diffraction （EBSD）. A field emission scanning electron microscope （...Texture evolution in extruded and hot-rolled Al-Mg-Li aeronautical alloys during in-situ tension was investigated by using elec-tron backscattered diffraction （EBSD）. A field emission scanning electron microscope （FE-SEM） and a MICROTEST-5000 tensile stage were used to carry out in-situ tension tests and observations. The crystallographic texture of the extruded sample changed from weak cube texture {001}〈100〉 to texture {018}〈081〉 during tension fracture. However, strong Brass {110}〈112〉 in the hot-rolled sample was modi-fied into a mixture texture component of Brass {110}〈112〉 and S {123}〈634〉 during tension fracture. Texture evolution in the two samples during tension can be explained by the rotation of grain orientation.展开更多
The microstructure and texture evolution of twin-roll cast A8006 alloy by homogenization were characterized using scanning and transmission electron microscopy, and the microhardness was tested as well. According to t...The microstructure and texture evolution of twin-roll cast A8006 alloy by homogenization were characterized using scanning and transmission electron microscopy, and the microhardness was tested as well. According to the relation- ship between dendritic arm spacing and cooling rate the cooling rate of the as-cast twin-roll cast A8006 sheet of 6 mm in thickness was estimated as 1.48×10^3 K·s^-1. It is found that the grains and the nanostructural precipitates of the twin-roll cast sheet become coarser after homogenization at 580℃ for 4 h in comparison with those after homogenization at 500℃ for 8 h. The textures formed after cold rolling and became weaker during homogenization. The increase in hardness of the as-cast twin-roll cast sheets is related in hardness after homogenization can to the supersaturated a-A1 solid solution and be attributed to the coarsening of grains and fine microstructure, but the decrease Al6Fe（Mn） precipitates.展开更多
BACKGROUND Langerhans cell histiocytosis(LCH)is a rare condition wherein Langerhans cells proliferate abnormally,adversely impacting organs including lymph nodes,bones,skin,lungs,and pituitary gland.The LCH disease co...BACKGROUND Langerhans cell histiocytosis(LCH)is a rare condition wherein Langerhans cells proliferate abnormally,adversely impacting organs including lymph nodes,bones,skin,lungs,and pituitary gland.The LCH disease course varies widely among patients from a self-limiting condition to one that progresses rapidly and culminates in death.It is uncommon for multisystem LCH to be observed in adults.Herein we describe a woman suffering from multi-system LCH involvement.CASE SUMMARY A 37-year old Chinese woman was admitted to the hospital in June 2019 suffering from dyspnea that had progressed over the course of 5 years.Her medical history included:central diabetes insipidus(DI)that had been treated via radiotherapy,desmopressin acetate,and bromocriptine;bilateral pneumothorax with two surgeries having been performed to remove bullae;and autoimmune hepatitis that had been unsuccessfully treated using a combination of methylprednisolone and mycophenolate mofetil.A chest computed tomography(CT)scan revealed the presence of multiple pulmonary cysts of varying sizes.We re-analyzed right pulmonary bullae samples that had been removed in 2014,performed a systematic 18 F-FDG PET/CT analysis,and convened a multidisciplinary medical team to diagnose and treat this patient.As a result,we were able to eventually diagnose this patient with LCH that was not associated with BRAF-V600 E mutations.CONCLUSION We hope to emphasize the importance of systemic evaluation and of cooperation between multidisciplinary physicians with the goal of improving awareness and detection of this orphan disease.展开更多
Grain microtexture evolution in twin-roll cast AA8006 alloy sheets subjected to different treatments was investigated using elec- tron backscatter diffraction. The textures of rolling-transverse and normal-transverse ...Grain microtexture evolution in twin-roll cast AA8006 alloy sheets subjected to different treatments was investigated using elec- tron backscatter diffraction. The textures of rolling-transverse and normal-transverse sections were characterized in original as-cast twin-roll casting and cold-rolled samples as well as samples homogenized at 500℃for 8 h and at 580℃ for 4 h. It is found that grains on both the rolling-transverse and normal-transverse sections of cold-rolled samples are made fmer by rolling deformation and coarsened after homog- enization. Annealing temperature has a stronger effect on the microstructural evolution than annealing time. The grain growth direction is parallel to the normal-transverse section, while grain deformation is more stable on the rolling direction than on the normal direction. The rolling orientations display more obvious anisotropy on the normal-transverse sections than on the rolling-transverse sections. Grain recrys- tallization and growth occur much easier on the normal-transverse section than on the rolling-transverse section for samples homogenized at 500℃ for 8 h. A special misorientation relationship between cold deformation texture, such as S orientation { 123 } 〈634〉 and cube orienta- tion 〈110〉Xaxis [cubic], and recrystallization texture after homogenization, such as R orientation { 124}〈211〉 and P orientation {011 }〈122〉, is observed.展开更多
Background:Currently,there are no effective methods for assessing hepatic inflammation without resorting to histological examination of liver tissue obtained by biopsy.T2-weighted images(T2WI)are routinely obtained fr...Background:Currently,there are no effective methods for assessing hepatic inflammation without resorting to histological examination of liver tissue obtained by biopsy.T2-weighted images(T2WI)are routinely obtained from liver magnetic resonance imaging(MRI)scan sequences.We aimed to establish a radiomics signature based on T2WI(T2-RS)for assessment of hepatic inflammation in people with nonalcoholic fatty liver disease(NAFLD).Methods:A total of 203 individuals with biopsy-confirmed NAFLD from two independent Chinese cohorts with liver MRI examination were enrolled in this study.The hepatic inflammatory activity score(IAS)was calculated by the unweighted sum of the histologic scores for lobular inflammation and ballooning.One thousand and thirty-two radiomics features were extracted from the localized region of interest(ROI)in the right liver lobe of T2WI and,subsequently,selected by minimum redundancy maximum relevance and least absolute shrinkage and selection operator(LASSO)methods.The T2-RS was calculated by adding the selected features weighted by their coefficients.Results:Eighteen radiomics features from Laplacian of Gaussian,wavelet,and original images were selected for establishing T2-RS.The T2-RS value differed significantly between groups with increasing grades of hepatic inflammation(P<0.01).The T2-RS yielded an area under the receiver operating characteristic(ROC)curve(AUROC)of 0.80[95%confidence interval(CI):0.71-0.89]for predicting hepatic inflammation in the training cohort with excellent calibration.The AUROCs of T2-RS in the internal cohort and external validation cohorts were 0.77(0.61-0.93)and 0.75(0.63-0.84),respectively.Conclusions:The T2-RS derived from radiomics analysis of T2WI shows promising utility for predicting hepatic inflammation in individuals with NAFLD.展开更多
基金supported by Open Project Funding of the Key Laboratory of Fermentation Engineering(Ministry of Education)(No.202209EF09)the Natural Science Foundation of Hubei Province(No.2021CFB289)+1 种基金the Key R&D Project of Hubei Province(No.2022BCA018)the initial funding of Hubei University of Technology(No.XJ2022002201).
文摘Objective Lindqvist-type polyoxometalates(POMs)exhibit potential antitumor activities.This study aimed to examine the effects of Lindqvist-type POMs against breast cancer and the underlying mechanism.Methods Using different cancer cell lines,the present study evaluated the antitumor activities of POM analogues that were modified at the body skeleton based on molybdenum-vanadium-centered negative oxygen ion polycondensations with different side strains.Cell colony formation assay,autophagy detection,mitochondrial observation,qRT-PCR,Western blotting,and animal model were used to evaluate the antitumor activities of POMs against breast cancer cells and the related mechanism.Results MO-4,a Lindqvist-type POM linking a proline at its side strain,was selected for subsequent experiments due to its low half maximal inhibitory concentration in the inhibition of proliferation of breast cancer cells.It was found that MO-4 induced the apoptosis of multiple types of breast cancer cells.Mechanistically,MO-4 activated intracellular mitophagy by elevating mitochondrial reactive oxygen species(ROS)levels and resulting in apoptosis.In vivo,breast tumor growth and distant metastasis were significantly reduced following MO-4 treatment.Conclusion Collectively,the results of the present study demonstrated that the novel Lindqvist-type POM MO-4 may exhibit potential in the treatment of breast cancer.
基金Supported by CAMS Innovation Fund for Medical Sciences,No.2016-I2M-1-001PUMC Youth Fund,No.2017320010+1 种基金Chinese Academy of Medical Sciences Research Fund,No.ZZ2016B01Beijing HopeRun Special Fund of Cancer Foundation of China,No.LC2016B15
文摘BACKGROUND Hepatocellular carcinoma(HCC)ranks second in terms of cancer mortality worldwide.Molecular magnetic resonance imaging(MRI)targeting HCC biomarkers such as alpha-fetoprotein(AFP)or glypican-3(GPC3)offers new strategies to enhance specificity and help early diagnosis of HCC.However,the existing iron oxide nanoparticle-based MR molecular probes singly target AFP or GPC3,which may hinder their efficiency to detect heterogeneous micro malignant HCC tumors<1 cm(MHCC).We hypothesized that the strategy of double antibody-conjugated iron oxide nanoparticles which simultaneously target AFP and GPC3 antigens may potentially be used to overcome the tumor heterogeneity and enhance the detection rate for MRI-based MHCC diagnosis.AIM To synthesize an AFP/GPC3 double antibody-labeled iron oxide MRI molecular probe and to assess its impact on MRI specificity and sensitivity at the cellular level.METHODS A double antigen-targeted MRI probe for MHCC anti-AFP-USPIO-anti-GPC3(UAG)was developed by simultaneously conjugating AFP andGPC3 antibodies to a 5 nm ultra-small superparamagnetic iron oxide nanoparticle(USPIO).At the same time,the singly labeled probes of anti-AFP-USPIO(UA)and anti-GPC3-USPIO(UG)and non-targeted USPIO(U)were also prepared for comparison.The physical characterization including morphology(transmission electron microscopy),hydrodynamic size,and zeta potential(dynamic light scattering)was conducted for each of the probes.The antigen targeting and MRI ability for these four kinds of USPIO probes were studied in the GPC3-expressing murine hepatoma cell line Hepa1-6/GPC3.First,AFP and GPC3 antigen expression in Hepa1-6/GPC3 cells was confirmed by flow cytometry and immunocytochemistry.Then,the cellular uptake of USPIO probes was investigated by Prussian blue staining assay and in vitro MRI(T2-weighted and T2-map)with a 3.0 Tesla clinical MR scanner.RESULTS Our data showed that the double antibody-conjugated probe UAG had the best specificity in targeting Hepa1-6/GPC3 cells expressing AFP and GPC3 antigens compared with single antibody-conjugated and unconjugated USPIO probes.The iron Prussian blue staining and quantitative T2-map MRI analysis showed that,compared with UA,UG,and U,the uptake of double antigen-targeted UAG probe demonstrated a 23.3%(vs UA),15.4%(vs UG),and 57.3%(vs U)increased Prussian stained cell percentage and a 14.93%(vs UA),9.38%(vs UG),and 15.3%(vs U)reduction of T2 relaxation time,respectively.Such bi-specific probe might have the potential to overcome tumor heterogeneity.Meanwhile,the coupling of two antibodies did not influence the magnetic performance of USPIO,and the relatively small hydrodynamic size(59.60±1.87 nm)of double antibodyconjugated USPIO probe makes it a viable candidate for use in MHCC MRI in vivo,as they are slowly phagocytosed by macrophages.CONCLUSION The bi-specific probe presents enhanced targeting efficiency and MRI sensitivity to HCC cells than singly-or non-targeted USPIO,paving the way for in vivo translation to further evaluate its clinical potential.
文摘Introduction:Breast cancer is a leading tumor with a high mortality in women.This study examined the spatio-temporal distribution of the incidence of female breast cancer in Shenzhen between 2007 and 2012.Methods:The data on breast cancer incidence were obtained from the Shenzhen Cancer Registry System.To describe the temporal trend,the average annual percentage change(AAPC) was analyzed using a pinpoint regression model.Spatial autocorrelation and a retrospective spatio-temporal scan approach were used to detect the spatio-temporal cluster distribution of breast cancer cases.Results:Breast cancer ranked first among different types of cancer in women in Shenzhen between 2007 and 2012 with a crude incidence of 20.0/100,000 population.The age-standardized rate according to the world standard population was 21.1/100,000 in 2012,with an AAPC of 11.3%.The spatial autocorrelation analysis showed a spatial correlation characterized by the presence of a hotspot in south-central Shenzhen,which included the eastern part of Luohu District(Donghu and Liantang Streets) and Yantian District(Shatoujiao,Haishan,and Yantian Streets).Five spatio-temporal cluster areas were detected between 2010 and 2012,one of which was a Class 1 cluster located in southwestern Shenzhen in 2010,which included Yuehai,Nantou,Shahe,Shekou,and Nanshan Streets in Nanshan District with an incidence of 54.1/100,000 and a relative risk of 2.41;the other four were Class 2 clusters located in Yantian,Luohu,Futian,and Longhua Districts with a relative risk ranging from 1.70 to 3.25.Conclusions:This study revealed the spatio-temporal cluster pattern for the incidence of female breast cancer in Shenzhen,which will be useful for a better allocation of health resources in Shenzhen.
基金supported by the Research Fund of the State Key Laboratory of Solidification Processing (No.42-QP-009)the Open Fund of the State Key Laboratory of Solidification Processing in NWPU (No.201009)+1 种基金the Fundamental Research Fund of Northwestern Polytechnical University (No.JC200929)the 111 Project of China (No.B08040)
文摘To determine the modifying agents for Al-7Si alloys, microstructure observation and mixing enthalpy analysis using Miedema model for Al-7Si alloy with additions of different rare earth elements were performed, and the effects of rare earth elements on the modifica-tion of eutectic silicon morphology were investigated. The results of mixing enthalpy analysis show that these four rare earth elements, La, Sm, Pr, and Ce, which have the large negative mixing enthalpies with Si, can be selected as modifying agents for eutectic silicon morphology. The element with the largest negative mixing enthalpy is Ce. Furthermore, the microstructures indicate that these four elements can effec-tively modify the eutectic （α）Al-Si crystals in Al-7Si alloy, and the most effective one is also Ce. Differential scanning calorimetry （DSC） results show that the eutectic temperature depressions due to the additions of modifying agents are the important reasons for the modification of eutectic （α）Al-Si crystals.
基金financially supported by the Aeronautical Science Foundation of China(No.2012ZF53080)the Shaanxi Province Science and Technology Research and Development Program of China(No.2013K08-11)+1 种基金the Fund of the State Key Laboratory of Solidification Processing in Northwestern Polytechnical University(No.SKLSP201009)the 111 Project of China(No.B08040)
文摘The mechanical properties of Al-Cu-Mn casting alloy mainly depend on the morphology, distribution, size, and number ofθ′（Al2Cu） precipitates. In this study, we have analyzed the effect of rare earth samarium （Sm） addition on the kinetics of precipitation in the Al-Cu-Mn casting alloy by using differential scanning calorimetry （DSC） and high-resolution transmission electron microscopy. Thermal ef-fect peaks that are attributed to the formation and the dissolution of Guinier-Preston （GP） zone andθ′phase were identified from the DSC curves. The activation energy ofθ′formation was calculated by using both the Kissinger method and the analytical model, and the corre-sponding results were compared. Results suggest that the activation energy ofθ′formation in Al-Cu-Mn alloy is dramatically higher than that in Al-Cu-Mn-Sm alloy. Accordingly, it is concluded that the addition of rare earth Sm decreases the activation energy ofθ′formation and promotes the formation ofθ′precipitates.
基金financial support from the Aeronautical Science Foundation of China (No. 2012ZF53080)the Shaanxi Province Science and Technology Research and Development Program of China (No. 2013K08-11)the 111 Project of China (No. B08040)
文摘The microstructural characteristics and microhardness of nanostructured Al-4.6Cu-Mn ribbons produced by melt spinning were investigated using field-emission gun scanning electron microscopy, transmission electron microscopy, and hardness testing, and the results were compared to those of similar ribbons manufactured by direct-chill casting. It is shown that the nanostructure of the as-melt-spun ribbons consists of α-Al dendrites with a secondary dendrite arm spacing of approximately 0.55-0.80 μm and ultrafine eutectic crystals of a nanosized scale of approximately 100-200 nm on dendritic boundaries. The solidification time and cooling rate of 46-μm-thick ribbons were estimated to be 1.3 × 10-6 s and 4.04 × 106 K·s-1, respectively. At an aging temperature of 190°C, the coherent θ″ phase in aged ribbons gradually transforms into nanoscale θ′-phase platelets as the aging time is extended from 2 to 8 h; the rod-like morphology of the T(Al20Cu2Mn3) dispersoid with 120-160-nm diameter also forms, which results in peak aging hardness. The precipitation behaviors of aged ribbons cannot be changed at the high cooling rates of as-cast ribbons. However, a finer and more uniformly distributed microstructure and a supersaturated solid solution at a high cooling rate can shorten the time required to obtain a certain aging hardness before peak hardness.
基金Project(51674204)supported by the National Natural Science Foundation of ChinaProject(2016GY-219)supported by Shaanxi Provincial Science and Technology Research and Development Program of China
文摘The present study focused on the formation and crystallographic orientation of twinned dendrites coexisting with equiaxed grains in unidirectional solidification of Al-32%Zn(mass fraction)alloy.The morphology was investigated by optical metallograph and electron back-scattered diffraction technique.Results showed that the macrostructure of the alloy exhibited a typical feathery and fan-like structure while the microstructures were elongated lamellas,which were separated by coherent and incoherent twin boundaries.Both the primary trunk and all lateral arms of twinned dendrites grew along〈110〉directions,unlike regular〈100〉α(Al)dendrites.The facet growth of crystals at solid/liquid interface was responsible for the origin of twinned dendrites during the weak local convection,and high thermal gradient and medium solidification velocity had significant contribution to the formation of twinned dendrites.The formation mechanism of twinned dendrites which consisted of three multiplication ways of new twin boundaries formation and one way of dendrite evolution in twin plane was shown schematically.
基金supported by the Innovation Fund of China Aerospace Science and Technology Corporation (2011)the Research Fund of the State Key Laboratory of Solidification Processing (No.42-QP-009)the 111 Project of China (No.B08040)
文摘Texture evolution in extruded and hot-rolled Al-Mg-Li aeronautical alloys during in-situ tension was investigated by using elec-tron backscattered diffraction （EBSD）. A field emission scanning electron microscope （FE-SEM） and a MICROTEST-5000 tensile stage were used to carry out in-situ tension tests and observations. The crystallographic texture of the extruded sample changed from weak cube texture {001}〈100〉 to texture {018}〈081〉 during tension fracture. However, strong Brass {110}〈112〉 in the hot-rolled sample was modi-fied into a mixture texture component of Brass {110}〈112〉 and S {123}〈634〉 during tension fracture. Texture evolution in the two samples during tension can be explained by the rotation of grain orientation.
基金supported by the Research Fund of the State Key Laboratory of Solidification Processing(No.42-QP-009)the 111 Project of China(No.B08040)
文摘The microstructure and texture evolution of twin-roll cast A8006 alloy by homogenization were characterized using scanning and transmission electron microscopy, and the microhardness was tested as well. According to the relation- ship between dendritic arm spacing and cooling rate the cooling rate of the as-cast twin-roll cast A8006 sheet of 6 mm in thickness was estimated as 1.48×10^3 K·s^-1. It is found that the grains and the nanostructural precipitates of the twin-roll cast sheet become coarser after homogenization at 580℃ for 4 h in comparison with those after homogenization at 500℃ for 8 h. The textures formed after cold rolling and became weaker during homogenization. The increase in hardness of the as-cast twin-roll cast sheets is related in hardness after homogenization can to the supersaturated a-A1 solid solution and be attributed to the coarsening of grains and fine microstructure, but the decrease Al6Fe（Mn） precipitates.
文摘BACKGROUND Langerhans cell histiocytosis(LCH)is a rare condition wherein Langerhans cells proliferate abnormally,adversely impacting organs including lymph nodes,bones,skin,lungs,and pituitary gland.The LCH disease course varies widely among patients from a self-limiting condition to one that progresses rapidly and culminates in death.It is uncommon for multisystem LCH to be observed in adults.Herein we describe a woman suffering from multi-system LCH involvement.CASE SUMMARY A 37-year old Chinese woman was admitted to the hospital in June 2019 suffering from dyspnea that had progressed over the course of 5 years.Her medical history included:central diabetes insipidus(DI)that had been treated via radiotherapy,desmopressin acetate,and bromocriptine;bilateral pneumothorax with two surgeries having been performed to remove bullae;and autoimmune hepatitis that had been unsuccessfully treated using a combination of methylprednisolone and mycophenolate mofetil.A chest computed tomography(CT)scan revealed the presence of multiple pulmonary cysts of varying sizes.We re-analyzed right pulmonary bullae samples that had been removed in 2014,performed a systematic 18 F-FDG PET/CT analysis,and convened a multidisciplinary medical team to diagnose and treat this patient.As a result,we were able to eventually diagnose this patient with LCH that was not associated with BRAF-V600 E mutations.CONCLUSION We hope to emphasize the importance of systemic evaluation and of cooperation between multidisciplinary physicians with the goal of improving awareness and detection of this orphan disease.
基金financial support from the Aeronautical Science Foundation of China (No. 2012ZF53080)the "111" Project of China (No. B08040)
文摘Grain microtexture evolution in twin-roll cast AA8006 alloy sheets subjected to different treatments was investigated using elec- tron backscatter diffraction. The textures of rolling-transverse and normal-transverse sections were characterized in original as-cast twin-roll casting and cold-rolled samples as well as samples homogenized at 500℃for 8 h and at 580℃ for 4 h. It is found that grains on both the rolling-transverse and normal-transverse sections of cold-rolled samples are made fmer by rolling deformation and coarsened after homog- enization. Annealing temperature has a stronger effect on the microstructural evolution than annealing time. The grain growth direction is parallel to the normal-transverse section, while grain deformation is more stable on the rolling direction than on the normal direction. The rolling orientations display more obvious anisotropy on the normal-transverse sections than on the rolling-transverse sections. Grain recrys- tallization and growth occur much easier on the normal-transverse section than on the rolling-transverse section for samples homogenized at 500℃ for 8 h. A special misorientation relationship between cold deformation texture, such as S orientation { 123 } 〈634〉 and cube orienta- tion 〈110〉Xaxis [cubic], and recrystallization texture after homogenization, such as R orientation { 124}〈211〉 and P orientation {011 }〈122〉, is observed.
基金supported by grants from the National Natural Science Foundation of China(82070588)High Level Creative Talents from Department of Public Health in Zhejiang Province(S2032102600032)+1 种基金Project of New Century 551 Talent Nurturing in Wenzhou.GT is supported in part by grants from the University School of Medicine of Verona,Verona,ItalyCDB is supported in part by the Southampton NIHR Biomedical Research Centre(IS-BRC-20004),UK.
文摘Background:Currently,there are no effective methods for assessing hepatic inflammation without resorting to histological examination of liver tissue obtained by biopsy.T2-weighted images(T2WI)are routinely obtained from liver magnetic resonance imaging(MRI)scan sequences.We aimed to establish a radiomics signature based on T2WI(T2-RS)for assessment of hepatic inflammation in people with nonalcoholic fatty liver disease(NAFLD).Methods:A total of 203 individuals with biopsy-confirmed NAFLD from two independent Chinese cohorts with liver MRI examination were enrolled in this study.The hepatic inflammatory activity score(IAS)was calculated by the unweighted sum of the histologic scores for lobular inflammation and ballooning.One thousand and thirty-two radiomics features were extracted from the localized region of interest(ROI)in the right liver lobe of T2WI and,subsequently,selected by minimum redundancy maximum relevance and least absolute shrinkage and selection operator(LASSO)methods.The T2-RS was calculated by adding the selected features weighted by their coefficients.Results:Eighteen radiomics features from Laplacian of Gaussian,wavelet,and original images were selected for establishing T2-RS.The T2-RS value differed significantly between groups with increasing grades of hepatic inflammation(P<0.01).The T2-RS yielded an area under the receiver operating characteristic(ROC)curve(AUROC)of 0.80[95%confidence interval(CI):0.71-0.89]for predicting hepatic inflammation in the training cohort with excellent calibration.The AUROCs of T2-RS in the internal cohort and external validation cohorts were 0.77(0.61-0.93)and 0.75(0.63-0.84),respectively.Conclusions:The T2-RS derived from radiomics analysis of T2WI shows promising utility for predicting hepatic inflammation in individuals with NAFLD.
