Spectral computed tomography(CT)based on photon counting detectors can resolve the energy of every single photon interacting with the sensor layer and be used to analyze material attenuation information under differen...Spectral computed tomography(CT)based on photon counting detectors can resolve the energy of every single photon interacting with the sensor layer and be used to analyze material attenuation information under different energy ranges,which can be helpful for material decomposition studies.However,there is a considerable amount of inherent quantum noise in narrow energy bins,resulting in a low signal-to-noise ratio,which can consequently affect the material decomposition performance in the image domain.Deep learning technology is currently widely used in medical image segmentation,denoising,and recognition.In order to improve the results of material decomposition,we propose an attention-based global convolutional generative adversarial network(AGC-GAN)to decompose different materials for spectral CT.Specifically,our network is a global convolutional neural network based on an attention mechanism that is combined with a generative adversarial network.The global convolutional network based on the attention mechanism is used as the generator,and a patchGAN discriminant network is used as the discriminator.Meanwhile,a clinical spectral CT image dataset is used to verify the feasibility of our proposed approach.Extensive experimental results demonstrate that AGC-GAN achieves a better material decomposition performance than vanilla U-Net,fully convolutional network,and fully convolutional denseNet.Remarkably,the mean intersection over union,structural similarity,mean precision,PAcc,and mean F1-score of our method reach up to 87.31%,94.83%,93.22%,97.39%,and 93.05%,respectively.展开更多
Hair follicles(HFs)undergo cycles of degeneration(catagen),rest(telogen),and regeneration(anagen)phases.Anagen begins when the hair follicle stem cells(HFSCs)obtain sufficient activation cues to overcome suppressive s...Hair follicles(HFs)undergo cycles of degeneration(catagen),rest(telogen),and regeneration(anagen)phases.Anagen begins when the hair follicle stem cells(HFSCs)obtain sufficient activation cues to overcome suppressive signals,mainly the BMP pathway,from their niche cells.Here,we unveil that mTOR complex 1(mTORC1)signaling is activated in HFSCs,which coincides with the HFSC activation at the telogen-to-anagen transition.By using both an inducible conditional gene targeting strategy and a pharmacological inhibition method to ablate or inhibit mTOR signaling in adult skin epithelium before anagen initiation,we demonstrate that HFs that cannot respond to mTOR signaling display significantly delayed HFSC activation and extended telogen.Unexpectedly,BMP signaling activity is dramatically prolonged in mTOR signaling-deficient HFs.Through both gain-and loss-of-function studies in vitro,we show that mTORC1 signaling negatively affects BMP signaling,which serves as a main mechanism whereby mTORC1 signaling facilitates HFSC activation.Indeed,in vivo suppression of BMP by its antagonist Noggin rescues the HFSC activation defect in mTORC1-null skin.Our findings reveal a critical role for mTOR signaling in regulating stem cell activation through counterbalancing BMP-mediated repression during hair regeneration.展开更多
With the extension of the deep space exploration program, the boundaries of human exploration will be pushed forward to the surface of Mars. Over the past nearly 60 years manned spaceflight and experimental fin dings ...With the extension of the deep space exploration program, the boundaries of human exploration will be pushed forward to the surface of Mars. Over the past nearly 60 years manned spaceflight and experimental fin dings dem on strated that spaceflight induced bone loss, muscle atrophy, cardiovascular remodeling and space-related medical problems (Durante and Cucinotta, 2008).展开更多
Dear Editor,Sperm cooperation has been observed in multiple species(Pizzari and Foster,2008),yet its existenee and benefit for reproductive success in mammals remains underexplored.Here,combining tissue-clearing with ...Dear Editor,Sperm cooperation has been observed in multiple species(Pizzari and Foster,2008),yet its existenee and benefit for reproductive success in mammals remains underexplored.Here,combining tissue-clearing with deep three-dimensional(3D)imagi ng,we dem on strate that postcopulatory mouse sperm congregate into unidirectional sperm cooperative clusters at the utero-tubal junction(UTJ),a key physical barrier for passage into the oviduct.展开更多
基金supported by National Natural Science Foundation of China (No.62101136)Shanghai Sailing Program (No.21YF1402800)+3 种基金Shanghai Municipal Science and Technology Major Project (No.2018SHZDZX01)ZJLab,Shanghai Municipal of Science and Technology Project (No.20JC1419500)Natural Science Foundation of Chongqing (No.CSTB2022NSCQ-MSX0360)Shanghai Center for Brain Science and Brain-inspired Technology.
文摘Spectral computed tomography(CT)based on photon counting detectors can resolve the energy of every single photon interacting with the sensor layer and be used to analyze material attenuation information under different energy ranges,which can be helpful for material decomposition studies.However,there is a considerable amount of inherent quantum noise in narrow energy bins,resulting in a low signal-to-noise ratio,which can consequently affect the material decomposition performance in the image domain.Deep learning technology is currently widely used in medical image segmentation,denoising,and recognition.In order to improve the results of material decomposition,we propose an attention-based global convolutional generative adversarial network(AGC-GAN)to decompose different materials for spectral CT.Specifically,our network is a global convolutional neural network based on an attention mechanism that is combined with a generative adversarial network.The global convolutional network based on the attention mechanism is used as the generator,and a patchGAN discriminant network is used as the discriminator.Meanwhile,a clinical spectral CT image dataset is used to verify the feasibility of our proposed approach.Extensive experimental results demonstrate that AGC-GAN achieves a better material decomposition performance than vanilla U-Net,fully convolutional network,and fully convolutional denseNet.Remarkably,the mean intersection over union,structural similarity,mean precision,PAcc,and mean F1-score of our method reach up to 87.31%,94.83%,93.22%,97.39%,and 93.05%,respectively.
基金This work was supported by grants from the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA 01010202 to E.D.and XDA 04020202-20)the National Basic Research Program of China(2011CB710905 to E.D.)the National Natural Science Foundation of China(31201099 to S.L.and 31471287 to E.D.).
文摘Hair follicles(HFs)undergo cycles of degeneration(catagen),rest(telogen),and regeneration(anagen)phases.Anagen begins when the hair follicle stem cells(HFSCs)obtain sufficient activation cues to overcome suppressive signals,mainly the BMP pathway,from their niche cells.Here,we unveil that mTOR complex 1(mTORC1)signaling is activated in HFSCs,which coincides with the HFSC activation at the telogen-to-anagen transition.By using both an inducible conditional gene targeting strategy and a pharmacological inhibition method to ablate or inhibit mTOR signaling in adult skin epithelium before anagen initiation,we demonstrate that HFs that cannot respond to mTOR signaling display significantly delayed HFSC activation and extended telogen.Unexpectedly,BMP signaling activity is dramatically prolonged in mTOR signaling-deficient HFs.Through both gain-and loss-of-function studies in vitro,we show that mTORC1 signaling negatively affects BMP signaling,which serves as a main mechanism whereby mTORC1 signaling facilitates HFSC activation.Indeed,in vivo suppression of BMP by its antagonist Noggin rescues the HFSC activation defect in mTORC1-null skin.Our findings reveal a critical role for mTOR signaling in regulating stem cell activation through counterbalancing BMP-mediated repression during hair regeneration.
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 81801872 and 31600683)Advanced Space Medico? Engineering Research Project of China (020103). The authors declare that they have no conflict of interest.
文摘With the extension of the deep space exploration program, the boundaries of human exploration will be pushed forward to the surface of Mars. Over the past nearly 60 years manned spaceflight and experimental fin dings dem on strated that spaceflight induced bone loss, muscle atrophy, cardiovascular remodeling and space-related medical problems (Durante and Cucinotta, 2008).
基金This work was supported by the National Key Research and Development Program of China(2018YFC1004500 to YZ,2019YFA0802600 to YZ,2016YFA0500903 to ED,2017YFC1001401 to ED,2015CB943003 to YZ)the Strategic Priority Research Program of the CAS(XDA16020700 to HW)National Basic Research Program of China(81490742 to ED)+2 种基金National Natural Science Foundation of China(81490741 to HW,31671201 to YZ,31671568 to ED)Youth Inn ovation Promotion Association,CAS(Grant No.2016081 to YZ)The Eunice Kennedy Shriver Nation al Institute of Child Health and Human Development(grants HD088412 and P01HD087157)supports our studies of UTJ migration defects in mouse models.
文摘Dear Editor,Sperm cooperation has been observed in multiple species(Pizzari and Foster,2008),yet its existenee and benefit for reproductive success in mammals remains underexplored.Here,combining tissue-clearing with deep three-dimensional(3D)imagi ng,we dem on strate that postcopulatory mouse sperm congregate into unidirectional sperm cooperative clusters at the utero-tubal junction(UTJ),a key physical barrier for passage into the oviduct.
