Autografting is the gold standard for surgical repair of nerve defects>5 mm in length;however,autografting is associated with potential complications at the nerve donor site.As an alternative,nerve guidance conduit...Autografting is the gold standard for surgical repair of nerve defects>5 mm in length;however,autografting is associated with potential complications at the nerve donor site.As an alternative,nerve guidance conduits may be used.The ideal conduit should be flexible,resistant to kinks and lumen collapse,and provide physical cues to guide nerve regeneration.We designed a novel flexible conduit using electrospinning technology to create fibers on the innermost surface of the nerve guidance conduit and employed melt spinning to align them.Subsequently,we prepared disordered electrospun fibers outside the aligned fibers and helical melt-spun fibers on the outer wall of the electrospun fiber lumen.The presence of aligned fibers on the inner surface can promote the extension of nerve cells along the fibers.The helical melt-spun fibers on the outer surface can enhance resistance to kinking and compression and provide stability.Our novel conduit promoted nerve regeneration and functional recovery in a rat sciatic nerve defect model,suggesting that it has potential for clinical use in human nerve injuries.展开更多
Brain encoding and decoding via functional magnetic resonance imaging(fMRI)are two important aspects of visual perception neuroscience.Although previous researchers have made significant advances in brain encoding and...Brain encoding and decoding via functional magnetic resonance imaging(fMRI)are two important aspects of visual perception neuroscience.Although previous researchers have made significant advances in brain encoding and decoding models,existing methods still require improvement using advanced machine learning techniques.For example,traditional methods usually build the encoding and decoding models separately,and are prone to overfitting on a small dataset.In fact,effectively unifying the encoding and decoding procedures may allow for more accurate predictions.In this paper,we first review the existing encoding and decoding methods and discuss the potential advantages of a“bidirectional”modeling strategy.Next,we show that there are correspondences between deep neural networks and human visual streams in terms of the architecture and computational rules.Furthermore,deep generative models(e.g.,variational autoencoders(VAEs)and generative adversarial networks(GANs))have produced promising results in studies on brain encoding and decoding.Finally,we propose that the dual learning method,which was originally designed for machine translation tasks,could help to improve the performance of encoding and decoding models by leveraging large-scale unpaired data.展开更多
In this work,based on physical vapor deposition and high-temperature annealing(HTA),the 4-inch crack-free high-quality AlN template is initialized.Benefiting from the crystal recrystallization during the HTA process,t...In this work,based on physical vapor deposition and high-temperature annealing(HTA),the 4-inch crack-free high-quality AlN template is initialized.Benefiting from the crystal recrystallization during the HTA process,the FWHMs of X-ray rocking curves for(002)and(102)planes are encouragingly decreased to 62 and 282 arcsec,respectively.On such an AlN template,an ultra-thin AlN with a thickness of~700 nm grown by MOCVD shows good quality,thus avoiding the epitaxial lateral over-growth(ELOG)process in which 3-4μm AlN is essential to obtain the flat surface and high crystalline quality.The 4-inch scaled wafer provides an avenue to match UVC-LED with the fabrication process of traditional GaN-based blue LED,therefore significantly improving yields and decreasing cost.展开更多
We show the structural and optical properties of non-polar a-plane GaN epitaxial films modified by Si ion implantation.Upon gradually raising Si fluences from 5×10^(13)cm^(-2)to 5×10^(15)cm^(-2),the n-type d...We show the structural and optical properties of non-polar a-plane GaN epitaxial films modified by Si ion implantation.Upon gradually raising Si fluences from 5×10^(13)cm^(-2)to 5×10^(15)cm^(-2),the n-type dopant concentration gradually increases from 4.6×10^(18)cm^(-2)to 4.5×10^(20)cm^(-2),while the generated vacancy density accordingly raises from 3.7×10^(13)cm^(-2)to 3.8×10^(15)cm^(-2).Moreover,despite that the implantation enhances structural disorder,the epitaxial structure of the implanted region is still well preserved which is confirmed by Rutherford backscattering channeling spectrometry measurements.The monotonical uniaxial lattice expansion along the a direction(out-of-plane direction)is observed as a function of fluences till 1×10^(15)cm^(-2),which ceases at the overdose of 5×10^(15)cm^(-2)due to the partial amorphization in the surface region.Upon raising irradiation dose,a yellow emission in the as-grown sample is gradually quenched,probably due to the irradiation-induced generation of non-radiative recombination centers.展开更多
The biomaterials composed of mammalian extracellular matrix(ECM)have a great potential in pelvic floor tissue repair and functional reconstruction.However,bacterial infection does cause great damage to the repair func...The biomaterials composed of mammalian extracellular matrix(ECM)have a great potential in pelvic floor tissue repair and functional reconstruction.However,bacterial infection does cause great damage to the repair function of biomaterials which is the major problem in clinical utilization.Therefore,the development of biological materials with antimicrobial effect is of great clinical significance for pelvic floor repair.Chitosan/tigecycline(CS/TGC)antibacterial biofilm was prepared by coating CS/TGC nanoparticles on mammalian-derived ECM.Infrared spectroscopy,scanning electron microscopy,bacteriostasis circle assay and static dialysis methods were used to characterize the membrane.MTS assay kit and DAPI fluorescence staining were used to evaluate cytotoxicity and cell adhesion.The biocompatibility was assessed by subabdominal implantation model in goats.Subcutaneous antimicrobial test in rabbit back was used to evaluate the antimicrobial and repairing effects on the infected wounds in vivo.Infrared spectroscopy showed that the composite coating had been successfully modified.The antibacterial membrane retained the main structure of ECM multilayer fibers.In vitro release of biomaterials showed sustained release and stability.In vivo studies showed that the antibacterial biological membrane had low cytotoxicity,fast degradation,good compatibility,anti-infection and excellent repair ability.展开更多
Ultrasound(US)imaging is a non-invasive,real-time,economical,and convenient imaging modality that has been widely used in diagnosing and treating hepatic diseases.Artificial intelligence(AI)technology can predict or m...Ultrasound(US)imaging is a non-invasive,real-time,economical,and convenient imaging modality that has been widely used in diagnosing and treating hepatic diseases.Artificial intelligence(AI)technology can predict or make decisions based on the experience of clinical experts and knowledge obtained from training data.This technology can help clinicians improve the detection efficiency and evaluate hepatic diseases,promote clinical treatment of the liver,and predict the response of the liver after treatment.This review summarizes the current rapid development of US technology and related AI methods in the diagnosis and treatment of hepatic diseases.Covered topics include steatosis grading,fibrosis staging,detection of focal liver lesions,US image segmentation,multimodal image registration,and other applications.At present,the field of AI in US imaging is still in its early stages.With the future progress of AI technology,AI-based US imaging can further improve diagnosis,reduce medical costs,and optimize US-based clinical workflow.This technology has broad prospects for application to hepatic diseases.展开更多
基金supported by the National Natural Science Foundation of China,No.82202718the Natural Science Foundation of Beijing,No.L212050the China Postdoctoral Science Foundation,Nos.2019M664007,2021T140793(all to ZL)。
文摘Autografting is the gold standard for surgical repair of nerve defects>5 mm in length;however,autografting is associated with potential complications at the nerve donor site.As an alternative,nerve guidance conduits may be used.The ideal conduit should be flexible,resistant to kinks and lumen collapse,and provide physical cues to guide nerve regeneration.We designed a novel flexible conduit using electrospinning technology to create fibers on the innermost surface of the nerve guidance conduit and employed melt spinning to align them.Subsequently,we prepared disordered electrospun fibers outside the aligned fibers and helical melt-spun fibers on the outer wall of the electrospun fiber lumen.The presence of aligned fibers on the inner surface can promote the extension of nerve cells along the fibers.The helical melt-spun fibers on the outer surface can enhance resistance to kinking and compression and provide stability.Our novel conduit promoted nerve regeneration and functional recovery in a rat sciatic nerve defect model,suggesting that it has potential for clinical use in human nerve injuries.
基金This work was supported by the National Key Research and Development Program of China(2018YFC2001302)National Natural Science Foundation of China(91520202)+2 种基金Chinese Academy of Sciences Scientific Equipment Development Project(YJKYYQ20170050)Beijing Municipal Science and Technology Commission(Z181100008918010)Youth Innovation Promotion Association of Chinese Academy of Sciences,and Strategic Priority Research Program of Chinese Academy of Sciences(XDB32040200).
文摘Brain encoding and decoding via functional magnetic resonance imaging(fMRI)are two important aspects of visual perception neuroscience.Although previous researchers have made significant advances in brain encoding and decoding models,existing methods still require improvement using advanced machine learning techniques.For example,traditional methods usually build the encoding and decoding models separately,and are prone to overfitting on a small dataset.In fact,effectively unifying the encoding and decoding procedures may allow for more accurate predictions.In this paper,we first review the existing encoding and decoding methods and discuss the potential advantages of a“bidirectional”modeling strategy.Next,we show that there are correspondences between deep neural networks and human visual streams in terms of the architecture and computational rules.Furthermore,deep generative models(e.g.,variational autoencoders(VAEs)and generative adversarial networks(GANs))have produced promising results in studies on brain encoding and decoding.Finally,we propose that the dual learning method,which was originally designed for machine translation tasks,could help to improve the performance of encoding and decoding models by leveraging large-scale unpaired data.
基金supported by the Key-Area Research and Development Program of Guangdong Province(Nos.2019B121204004,2019B010132001)Science Challenge Project(No.TZ2018003)+1 种基金Basic and Application Basic Research Foundation of Guangdong Province(No.2020A1515110891)the National Natural Science Foundation of China(Nos.61734001,61521004).
文摘In this work,based on physical vapor deposition and high-temperature annealing(HTA),the 4-inch crack-free high-quality AlN template is initialized.Benefiting from the crystal recrystallization during the HTA process,the FWHMs of X-ray rocking curves for(002)and(102)planes are encouragingly decreased to 62 and 282 arcsec,respectively.On such an AlN template,an ultra-thin AlN with a thickness of~700 nm grown by MOCVD shows good quality,thus avoiding the epitaxial lateral over-growth(ELOG)process in which 3-4μm AlN is essential to obtain the flat surface and high crystalline quality.The 4-inch scaled wafer provides an avenue to match UVC-LED with the fabrication process of traditional GaN-based blue LED,therefore significantly improving yields and decreasing cost.
基金the Key-Area Research and Development Program of Guangdong Province,China(Grant Nos.2019B010132001,2020B010174003,and 2019B121204004)the Basic and Application Basic Research Foundation of Guangdong Province,China(Grant Nos.2020A1515110891 and 2019A1515111053)the Fund from the Ion Beam Center(IBC)at HZDR.
文摘We show the structural and optical properties of non-polar a-plane GaN epitaxial films modified by Si ion implantation.Upon gradually raising Si fluences from 5×10^(13)cm^(-2)to 5×10^(15)cm^(-2),the n-type dopant concentration gradually increases from 4.6×10^(18)cm^(-2)to 4.5×10^(20)cm^(-2),while the generated vacancy density accordingly raises from 3.7×10^(13)cm^(-2)to 3.8×10^(15)cm^(-2).Moreover,despite that the implantation enhances structural disorder,the epitaxial structure of the implanted region is still well preserved which is confirmed by Rutherford backscattering channeling spectrometry measurements.The monotonical uniaxial lattice expansion along the a direction(out-of-plane direction)is observed as a function of fluences till 1×10^(15)cm^(-2),which ceases at the overdose of 5×10^(15)cm^(-2)due to the partial amorphization in the surface region.Upon raising irradiation dose,a yellow emission in the as-grown sample is gradually quenched,probably due to the irradiation-induced generation of non-radiative recombination centers.
文摘The biomaterials composed of mammalian extracellular matrix(ECM)have a great potential in pelvic floor tissue repair and functional reconstruction.However,bacterial infection does cause great damage to the repair function of biomaterials which is the major problem in clinical utilization.Therefore,the development of biological materials with antimicrobial effect is of great clinical significance for pelvic floor repair.Chitosan/tigecycline(CS/TGC)antibacterial biofilm was prepared by coating CS/TGC nanoparticles on mammalian-derived ECM.Infrared spectroscopy,scanning electron microscopy,bacteriostasis circle assay and static dialysis methods were used to characterize the membrane.MTS assay kit and DAPI fluorescence staining were used to evaluate cytotoxicity and cell adhesion.The biocompatibility was assessed by subabdominal implantation model in goats.Subcutaneous antimicrobial test in rabbit back was used to evaluate the antimicrobial and repairing effects on the infected wounds in vivo.Infrared spectroscopy showed that the composite coating had been successfully modified.The antibacterial membrane retained the main structure of ECM multilayer fibers.In vitro release of biomaterials showed sustained release and stability.In vivo studies showed that the antibacterial biological membrane had low cytotoxicity,fast degradation,good compatibility,anti-infection and excellent repair ability.
基金The authors acknowledge support from the National Natural Science Foundation of China(81901844,82027807,61871251)the Beijing Municipal Natural Science Foundation(L192013,7212202,M22018).
文摘Ultrasound(US)imaging is a non-invasive,real-time,economical,and convenient imaging modality that has been widely used in diagnosing and treating hepatic diseases.Artificial intelligence(AI)technology can predict or make decisions based on the experience of clinical experts and knowledge obtained from training data.This technology can help clinicians improve the detection efficiency and evaluate hepatic diseases,promote clinical treatment of the liver,and predict the response of the liver after treatment.This review summarizes the current rapid development of US technology and related AI methods in the diagnosis and treatment of hepatic diseases.Covered topics include steatosis grading,fibrosis staging,detection of focal liver lesions,US image segmentation,multimodal image registration,and other applications.At present,the field of AI in US imaging is still in its early stages.With the future progress of AI technology,AI-based US imaging can further improve diagnosis,reduce medical costs,and optimize US-based clinical workflow.This technology has broad prospects for application to hepatic diseases.