The development of chemoresistance which results in a poor prognosis often renders current treatments for colorectal cancer(CRC).In this study,we identified reduced microvessel density(MVD)and vascular immaturity resu...The development of chemoresistance which results in a poor prognosis often renders current treatments for colorectal cancer(CRC).In this study,we identified reduced microvessel density(MVD)and vascular immaturity resulting from endothelial apoptosis as therapeutic targets for overcoming chemoresistance.We focused on the effect of metformin on MVD,vascular maturity,and endothelial apoptosis of CRCs with a non-angiogenic phenotype,and further investigated its effect in overcoming chemoresistance.In situ transplanted cancer models were established to compare MVD,endothelial apoptosis and vascular maturity,and function in tumors from metformin-and vehicle-treated mice.An in vitro co-culture system was used to observe the effects of metformin on tumor cell-induced endothelial apoptosis.Transcriptome sequencing was performed for genetic screening.Non-angiogenic CRC developed independently of angiogenesis and was characterized by vascular leakage,immaturity,reduced MVD,and non-hypoxia.This phenomenon had also been observed in human CRC.Furthermore,non-angiogenic CRCs showed a worse response to chemotherapeutic drugs in vivo than in vitro.By suppressing endothelial apoptosis,metformin sensitized non-angiogenic CRCs to chemo-drugs via elevation of MVD and improvement of vascular maturity.Further results showed that endothelial apoptosis was induced by tumor cells via activation of caspase signaling,which was abrogated by metformin administration.These findings provide pre-clinical evidence for the involvement of endothelial apoptosis and subsequent vascular immaturity in the chemoresistance of non-angiogenic CRC.By suppressing endothelial apoptosis,metformin restores vascular maturity and function and sensitizes CRC to chemotherapeutic drugs via a vascular mechanism.展开更多
Lung medical image retrieval based on content similarity plays an important role in computer-aided diagnosis of lung cancer.In recent years,binary hashing has become a hot topic in this field due to its compressed sto...Lung medical image retrieval based on content similarity plays an important role in computer-aided diagnosis of lung cancer.In recent years,binary hashing has become a hot topic in this field due to its compressed storage and fast query speed.Traditional hashing methods often rely on highdimensional features based hand-crafted methods,which might not be optimally compatible with lung nodule images.Also,different hashing bits contribute to the image retrieval differently,and therefore treating the hashing bits equally affects the retrieval accuracy.Hence,an image retrieval method of lung nodule images is proposed with the basis on convolutional neural networks and hashing.First,apre-trained and fine-tuned convolutional neural network is employed to learn multilevel semantic features of the lung nodules.Principal components analysis is utilized to remove redundant information and preserve informative semantic features of the lung nodules.Second,the proposed method relies on nine sign labels of lung nodules for the training set,and the semantic feature is combined to construct hashing functions.Finally,returned lung nodule images can be easily ranked with the query-adaptive search method based on weighted Hamming distance.Extensive experiments and evaluations on the dataset demonstrate that the proposed method can significantly improve the expression ability of lung nodule images,which further validates the effectiveness of the proposed method.展开更多
Grains with size of 4.5—20.5μm were studied for their corrosion behavior and electrochemical performance in a Mg-3 Al-5 Pb-1 Ga-Y sacrificial anode using immersion testing,electrochemical measurements and microstruc...Grains with size of 4.5—20.5μm were studied for their corrosion behavior and electrochemical performance in a Mg-3 Al-5 Pb-1 Ga-Y sacrificial anode using immersion testing,electrochemical measurements and microstructure analysis.The results show that fine-grained microstructure has higher chemical activity and more negative discharge potentials than coarse-grained samples.The sample with the smallest average grain size of 4.5μm exhibits corrosion current density of 7.473×10-5 A/cm2,and work potentials of-1.721 V at current density of 10 mA/cm2.The density of grain boundaries and LAGBs increases with grain refinement,which leads to higher rates of dissolution and diffusion for the atoms.The secondary phases promote the occurrence of corrosion and improve the chemical activity of alloy due to their higher potential than the substrate.Higher corrosion rate and discharge activity are directly attributed to the higher density of grain boundaries and LAGBs,as well as the secondary phase.展开更多
Ni-based self-lubricating composites containing a fixed amount of hexagonal boron nitride (h-BN)(5 wt%) and different amounts of graphene (0-1.5 wt%) were prepared by ultrasonic dispersion, high-energy ball milling, a...Ni-based self-lubricating composites containing a fixed amount of hexagonal boron nitride (h-BN)(5 wt%) and different amounts of graphene (0-1.5 wt%) were prepared by ultrasonic dispersion, high-energy ball milling, and spark plasma sintering. The effects of the graphene content on the physical, mechanical, and wear properties of the Ni/h-BN composites were evaluated. These properties were first enhanced with increasing graphene content, reaching optimal behavior for a graphene content of 1 wt%, and then degraded with further graphene addition. Compared to the pure Ni/h-BN composite, the relative density, hardness, and bending strength of the composite with 1 wt% graphene increased by 2.7%, 7.4%, and 6.3%, respectively, while the friction coefficient decreased by 56% to 0.31, and a reduction in wear rate by a factor of 5-15 was observed. The mechanism for improving the wear properties of the composite with added graphene was due to the formation of a graphene lubricating film on the worn surface, which increased the load bearing capacity of the surface and enhanced lubrication during wear.展开更多
基金supported by grants from the National Natural Science Foundation of China(Grant No.:81972811)the Key Research and Development Foundation of Shaanxi Province(Grant Nos.:2018SF-099,S2021SF-136,2021JM-273,and 2022JQ-848)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.:xzy012022094)the Provincial Science and Technology Rising Star(Grant No.:2021KJXX-03).
文摘The development of chemoresistance which results in a poor prognosis often renders current treatments for colorectal cancer(CRC).In this study,we identified reduced microvessel density(MVD)and vascular immaturity resulting from endothelial apoptosis as therapeutic targets for overcoming chemoresistance.We focused on the effect of metformin on MVD,vascular maturity,and endothelial apoptosis of CRCs with a non-angiogenic phenotype,and further investigated its effect in overcoming chemoresistance.In situ transplanted cancer models were established to compare MVD,endothelial apoptosis and vascular maturity,and function in tumors from metformin-and vehicle-treated mice.An in vitro co-culture system was used to observe the effects of metformin on tumor cell-induced endothelial apoptosis.Transcriptome sequencing was performed for genetic screening.Non-angiogenic CRC developed independently of angiogenesis and was characterized by vascular leakage,immaturity,reduced MVD,and non-hypoxia.This phenomenon had also been observed in human CRC.Furthermore,non-angiogenic CRCs showed a worse response to chemotherapeutic drugs in vivo than in vitro.By suppressing endothelial apoptosis,metformin sensitized non-angiogenic CRCs to chemo-drugs via elevation of MVD and improvement of vascular maturity.Further results showed that endothelial apoptosis was induced by tumor cells via activation of caspase signaling,which was abrogated by metformin administration.These findings provide pre-clinical evidence for the involvement of endothelial apoptosis and subsequent vascular immaturity in the chemoresistance of non-angiogenic CRC.By suppressing endothelial apoptosis,metformin restores vascular maturity and function and sensitizes CRC to chemotherapeutic drugs via a vascular mechanism.
基金Supported by the National Natural Science Foundation of China(61373100)the Open Funding Project of State Key Laboratory of Virtual Reality Technology and Systems(BUAA-VR-16KF-13,BUAA-VR-17KF-14,BUAA-VR-17KF-15)the Research Project Supported by Shanxi Scholarship Council of China(2016-038)
文摘Lung medical image retrieval based on content similarity plays an important role in computer-aided diagnosis of lung cancer.In recent years,binary hashing has become a hot topic in this field due to its compressed storage and fast query speed.Traditional hashing methods often rely on highdimensional features based hand-crafted methods,which might not be optimally compatible with lung nodule images.Also,different hashing bits contribute to the image retrieval differently,and therefore treating the hashing bits equally affects the retrieval accuracy.Hence,an image retrieval method of lung nodule images is proposed with the basis on convolutional neural networks and hashing.First,apre-trained and fine-tuned convolutional neural network is employed to learn multilevel semantic features of the lung nodules.Principal components analysis is utilized to remove redundant information and preserve informative semantic features of the lung nodules.Second,the proposed method relies on nine sign labels of lung nodules for the training set,and the semantic feature is combined to construct hashing functions.Finally,returned lung nodule images can be easily ranked with the query-adaptive search method based on weighted Hamming distance.Extensive experiments and evaluations on the dataset demonstrate that the proposed method can significantly improve the expression ability of lung nodule images,which further validates the effectiveness of the proposed method.
基金Project supported by the 2011 Program of the Ministry of Education in China(043010100,51701039)
文摘Grains with size of 4.5—20.5μm were studied for their corrosion behavior and electrochemical performance in a Mg-3 Al-5 Pb-1 Ga-Y sacrificial anode using immersion testing,electrochemical measurements and microstructure analysis.The results show that fine-grained microstructure has higher chemical activity and more negative discharge potentials than coarse-grained samples.The sample with the smallest average grain size of 4.5μm exhibits corrosion current density of 7.473×10-5 A/cm2,and work potentials of-1.721 V at current density of 10 mA/cm2.The density of grain boundaries and LAGBs increases with grain refinement,which leads to higher rates of dissolution and diffusion for the atoms.The secondary phases promote the occurrence of corrosion and improve the chemical activity of alloy due to their higher potential than the substrate.Higher corrosion rate and discharge activity are directly attributed to the higher density of grain boundaries and LAGBs,as well as the secondary phase.
基金Program of the Ministry of Education in China (2011)
文摘Ni-based self-lubricating composites containing a fixed amount of hexagonal boron nitride (h-BN)(5 wt%) and different amounts of graphene (0-1.5 wt%) were prepared by ultrasonic dispersion, high-energy ball milling, and spark plasma sintering. The effects of the graphene content on the physical, mechanical, and wear properties of the Ni/h-BN composites were evaluated. These properties were first enhanced with increasing graphene content, reaching optimal behavior for a graphene content of 1 wt%, and then degraded with further graphene addition. Compared to the pure Ni/h-BN composite, the relative density, hardness, and bending strength of the composite with 1 wt% graphene increased by 2.7%, 7.4%, and 6.3%, respectively, while the friction coefficient decreased by 56% to 0.31, and a reduction in wear rate by a factor of 5-15 was observed. The mechanism for improving the wear properties of the composite with added graphene was due to the formation of a graphene lubricating film on the worn surface, which increased the load bearing capacity of the surface and enhanced lubrication during wear.
