Block-in-matrix-soils(bimsoils)are geological mixtures that have distinct structures consisting of relatively strong rock blocks and weak matrix soils.It is still a challenge to evaluate the mechanical behaviors of bi...Block-in-matrix-soils(bimsoils)are geological mixtures that have distinct structures consisting of relatively strong rock blocks and weak matrix soils.It is still a challenge to evaluate the mechanical behaviors of bimsoils because of the heterogeneity,chaotic structure,and lithological variability.As a result,only very limited laboratory studies have been reported on the evolution of their internal deformation.In this study,the deformation evolution of bimsoils under uniaxial loading is investigated using real-time X-ray computed tomography(CT)and image correlation algorithm(with a rock block percentage(RBP)of 40%).Three parameters,i.e.heterogeneity coefficient(K),correlation coefficient(CC),and standard deviation(STD)of displacement fields,are proposed to quantify the heterogeneity of the motion of the rock blocks and the progressive deformation of the bimsoils.Experimental results show that the rock blocks in bimsoils are prone to forming clusters with increasing loading,and the sliding surface goes around only one side of a cluster.Based on the movement of the rock blocks recorded by STD and CC,the progressive deformation of the bimsoils is quantitatively divided into three stages:initialization of the rotation of rock blocks,formation of rock block clusters,and formation of a shear band by rock blocks with significant rotation.Moreover,the experimental results demonstrate that the meso-motion of rock blocks controls the macroscopic mechanical properties of the samples.展开更多
CT9 is a recently cloned cancer-testis antigen, which is a member of the bromodomain and extraterminal family. Each member of this protein family contains two N-terminal bromodomain motifs. We investigated the distrib...CT9 is a recently cloned cancer-testis antigen, which is a member of the bromodomain and extraterminal family. Each member of this protein family contains two N-terminal bromodomain motifs. We investigated the distribution of CT9 in different tissues and the possibility for it to be used as a potential therapeutic target in cancer treament. By using the real-time RT-PCR method and 18SrRNA as an internal standard, we analyzed the CT9 expression in several normal human tissues and in the tissues of patients suffering from cancer. The result of this study shows that the highest level of mRNA is only present in testis tissue because the CT9 expression has not been detected in other normal tissues. In 6 of 10 cases of gastric adenocarcinoma, in 3 of 10 cases of esophageal squamous cell carcinoma, in 2 of 9 cases of endometrial carcinoma and only in 1 of 12 cases of brain cancer, the low level expression of CT9 was detected. In none of the 12 cases of cervical squamous cell carcinoma, the expression of CT9 was detected. Since the high level expression of CT9 is only found in the normal testis tissue, but the low expression in cancer tissues, for example tissues of cervical squamous cell carcinoma, brain cancer, endometfial adenocarcinoma, esophageal squamous cell carcinoma, we conclude that CT9 cannot be used as a cancer therapeutic target molecule for cervical squamous cell carcinoma, brain cancer, endometrial adenocarcinoma, esophageal squamous cell carcinoma.展开更多
Proton FLASH therapy with an ultra-high dose rate is in urgent need of more accurate treatment plan system(TPS)to promote the development of proton computed tomography(CT)without intrinsic error compared with the tran...Proton FLASH therapy with an ultra-high dose rate is in urgent need of more accurate treatment plan system(TPS)to promote the development of proton computed tomography(CT)without intrinsic error compared with the transformation from X-ray CT.This paper presents an imaging mode of proton CT based on static superconducting gantry different from the conventional rotational gantry.The beam energy for proton CT is fixed at 350 MeV,which is boosted by a compact proton linac from 230 MeV,and then delivered by the gantry to scan the patient’s body for proton imaging.This study demonstrates that the static superconducting gantry-based proton CT is effective in clinical applications.In particular,the imaging mode,which combines the relative stopping power(RSP)map from X-ray CT as prior knowledge,can produce much a higher accuracy RSP map for TPSs and positioning and achieve ultra-fast image for real-time image-guided radiotherapy.This paper presents the conceptual design of a boosting linac,static superconducting gantry and proton CT imaging equipment.The feasibility of energy enhancement is verified by simulation,and results from Geant4 simulations and reconstruction algorithms are presented,including the simulation verification of the advantage of the imaging mode.展开更多
Proton computed tomography(CT)has a distinct practical significance in clinical applications.It eliminates 3–5%errors caused by the transformation of Hounsfield unit(HU)to relative stopping power(RSP)values when usin...Proton computed tomography(CT)has a distinct practical significance in clinical applications.It eliminates 3–5%errors caused by the transformation of Hounsfield unit(HU)to relative stopping power(RSP)values when using X-ray CT for positioning and treatment planning systems(TPSs).Following the development of FLASH proton therapy,there are increased requirements for accurate and rapid positioning in TPSs.Thus,a new rapid proton CT imaging mode is proposed based on sparsely sampled projections.The proton beam was boosted to 350 MeV by a compact proton linear accelerator(LINAC).In this study,the comparisons of the proton scattering with the energy of 350 MeV and 230 MeV are conducted based on GEANT4 simulations.As the sparsely sampled information associated with beam acquisitions at 12 angles is not enough for reconstruction,X-ray CT is used as a prior image.The RSP map generated by converting the X-ray CT was constructed based on Monte Carlo simulations.Considering the estimation of the most likely path(MLP),the prior image-constrained compressed sensing(PICCS)algorithm is used to reconstruct images from two different phantoms using sparse proton projections of 350 MeV parallel proton beam.The results show that it is feasible to realize the proton image reconstruction with the rapid proton CT imaging proposed in this paper.It can produce RSP maps with much higher accuracy for TPSs and fast positioning to achieve ultra-fast imaging for real-time image-guided radiotherapy(IGRT)in clinical proton therapy applications.展开更多
In civil aviation security screening, laptops, with their intricate structural composition, provide the potential for criminals to conceal dangerous items. Presently, the security process necessitates passengers to in...In civil aviation security screening, laptops, with their intricate structural composition, provide the potential for criminals to conceal dangerous items. Presently, the security process necessitates passengers to individually present their laptops for inspection. The paper introduced a method for laptop removal. By combining projection algorithms with the YOLOv7-Seg model, a laptop’s three views were generated through projection, and instance segmentation of these views was achieved using YOLOv7-Seg. The resulting 2D masks from instance segmentation at different angles were employed to reconstruct a 3D mask through angle restoration. Ultimately, the intersection of this 3D mask with the original 3D data enabled the successful extraction of the laptop’s 3D information. Experimental results demonstrated that the fusion of projection and instance segmentation facilitated the automatic removal of laptops from CT data. Moreover, higher instance segmentation model accuracy leads to more precise removal outcomes. By implementing the laptop removal functionality, the civil aviation security screening process becomes more efficient and convenient. Passengers will no longer be required to individually handle their laptops, effectively enhancing the efficiency and accuracy of security screening.展开更多
We sought to determine the characteristics of viral specimens associated with fatal cases,asymptomatic cases and non-fatal symptomatic cases of COVID-19.This included the analysis of 1264 specimens found reactive for ...We sought to determine the characteristics of viral specimens associated with fatal cases,asymptomatic cases and non-fatal symptomatic cases of COVID-19.This included the analysis of 1264 specimens found reactive for at least two SARS-CoV-2 specific loci from people screened for infection in Northern Nevada in March-May of 2020.Of these,30 were specimens from fatal cases,while 23 were from positive,asymptomatic cases.We assessed the relative amounts of SARS-CoV-2 RNA from sample swabs by real-time PCR and use of the threshold crossing value(Ct).Moreover,we compared the amount of human RNase P found on the same swabs.A considerably higher viral load was found to be associated with swabs from cases involving fatality and the difference was found to be strongly statistically significant.Noting this difference,we sought to assess whether any genetic correlation could be found in association with virus from fatal cases using whole genome sequencing.While no common genetic elements were discerned,one branch of epidemiologically linked fatal cases did have two point mutations,which no other of 156 sequenced cases from northern Nevada had.The mutations caused amino acid changes in the 3′-5′exonuclease protein,and the product of the gene,orf8.展开更多
Soil-rock mixture(SRM),as a type of extremely heterogeneous geomaterial,is very common in nature and engineering.The fracture and damage of SRM often induce severe geological disasters.Hence,it is important to analyze...Soil-rock mixture(SRM),as a type of extremely heterogeneous geomaterial,is very common in nature and engineering.The fracture and damage of SRM often induce severe geological disasters.Hence,it is important to analyze the fracture evolution process of this material.In the present research,real-time computed tomography(CT)scanning was conducted on SRM and pure soil samples under uniaxial compressive experiments to investigate the influence of rocks on fracture evolution in SRM.The initiation of cracks,the original values of,and variations in,average density and heterogeneity in the soil matrix,the crack width evolution during loading,and the final failure modes were all studied.Cracks with a width greater than 0.1 mm will not arise until over 90%of ultimate stress is reached.In general,in SRM,areas where the initial average density of the soil matrix is smaller and the initial heterogeneity is greater,are much easier to crack,but the results for pure soil show the opposite effect.According to fracturing conditions shown in CT slices,fracturing and non-fracturing areas in the soil matrix were investigated.The average density of the soil matrix decreases in all areas under loading,except non-fracturing areas in SRM.For the whole sample,the increase in heterogeneity in the soil matrix of SRM is greater than that of pure soil;but for the fracturing areas,this increase in pure soil is greater.Besides,the average and standard deviations of crack width both follow logarithmic distributions with high correlation coefficients.展开更多
目的应用循证医学Meta分析来评价CT和MRI对股骨头缺血坏死( avascular necrosis of the femoral head, ANFH)诊断的应用价值。方法检索cochrane图书馆(2011年第1期)、PubMed(1966~2011)、Embase(1989~2011)、中国生物医学文...目的应用循证医学Meta分析来评价CT和MRI对股骨头缺血坏死( avascular necrosis of the femoral head, ANFH)诊断的应用价值。方法检索cochrane图书馆(2011年第1期)、PubMed(1966~2011)、Embase(1989~2011)、中国生物医学文献数据库(1982~2011)、万方数据库(1982—2011),纳入国内外公开发表的关于股骨头缺血坏死的CT和MRI诊断的文献,按照纳入标准进行筛选,两名调查员独立对文献质量进行严格评价和资料提取,对符合标准的8篇文献在诊断ANFH方面使用软件Review mangager5.0进行Meta分析。结果共纳入8篇研究,共515例患者。Meta分析及其偏倚分歧提示MRI对股骨头缺血坏死阳性率的诊断价值高于CT,两者差别有显著统计学意义[OR=0.12(95%CI,0.04~0.33),P〈0.0001]。MRI对股骨头缺血坏死早期阳性率的诊断价值高于CT,两者差别有统计学意义[OR=0.45(95%CI,0.26~0.78),P=0.005]。结论MRI是首选的股骨头缺血坏死诊断手段,但仍需大样本随机对照试验来验证。展开更多
基金This work was supported by the National Natural Science Foundation of China(Grants Nos.41972287 and 42090023)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0904).
文摘Block-in-matrix-soils(bimsoils)are geological mixtures that have distinct structures consisting of relatively strong rock blocks and weak matrix soils.It is still a challenge to evaluate the mechanical behaviors of bimsoils because of the heterogeneity,chaotic structure,and lithological variability.As a result,only very limited laboratory studies have been reported on the evolution of their internal deformation.In this study,the deformation evolution of bimsoils under uniaxial loading is investigated using real-time X-ray computed tomography(CT)and image correlation algorithm(with a rock block percentage(RBP)of 40%).Three parameters,i.e.heterogeneity coefficient(K),correlation coefficient(CC),and standard deviation(STD)of displacement fields,are proposed to quantify the heterogeneity of the motion of the rock blocks and the progressive deformation of the bimsoils.Experimental results show that the rock blocks in bimsoils are prone to forming clusters with increasing loading,and the sliding surface goes around only one side of a cluster.Based on the movement of the rock blocks recorded by STD and CC,the progressive deformation of the bimsoils is quantitatively divided into three stages:initialization of the rotation of rock blocks,formation of rock block clusters,and formation of a shear band by rock blocks with significant rotation.Moreover,the experimental results demonstrate that the meso-motion of rock blocks controls the macroscopic mechanical properties of the samples.
文摘CT9 is a recently cloned cancer-testis antigen, which is a member of the bromodomain and extraterminal family. Each member of this protein family contains two N-terminal bromodomain motifs. We investigated the distribution of CT9 in different tissues and the possibility for it to be used as a potential therapeutic target in cancer treament. By using the real-time RT-PCR method and 18SrRNA as an internal standard, we analyzed the CT9 expression in several normal human tissues and in the tissues of patients suffering from cancer. The result of this study shows that the highest level of mRNA is only present in testis tissue because the CT9 expression has not been detected in other normal tissues. In 6 of 10 cases of gastric adenocarcinoma, in 3 of 10 cases of esophageal squamous cell carcinoma, in 2 of 9 cases of endometrial carcinoma and only in 1 of 12 cases of brain cancer, the low level expression of CT9 was detected. In none of the 12 cases of cervical squamous cell carcinoma, the expression of CT9 was detected. Since the high level expression of CT9 is only found in the normal testis tissue, but the low expression in cancer tissues, for example tissues of cervical squamous cell carcinoma, brain cancer, endometfial adenocarcinoma, esophageal squamous cell carcinoma, we conclude that CT9 cannot be used as a cancer therapeutic target molecule for cervical squamous cell carcinoma, brain cancer, endometrial adenocarcinoma, esophageal squamous cell carcinoma.
基金supported by the Research collaboration on Thailand new synchrotron light source facility(SPS-Ⅱ)(No.ANSO-CRKP-2020-16).
文摘Proton FLASH therapy with an ultra-high dose rate is in urgent need of more accurate treatment plan system(TPS)to promote the development of proton computed tomography(CT)without intrinsic error compared with the transformation from X-ray CT.This paper presents an imaging mode of proton CT based on static superconducting gantry different from the conventional rotational gantry.The beam energy for proton CT is fixed at 350 MeV,which is boosted by a compact proton linac from 230 MeV,and then delivered by the gantry to scan the patient’s body for proton imaging.This study demonstrates that the static superconducting gantry-based proton CT is effective in clinical applications.In particular,the imaging mode,which combines the relative stopping power(RSP)map from X-ray CT as prior knowledge,can produce much a higher accuracy RSP map for TPSs and positioning and achieve ultra-fast image for real-time image-guided radiotherapy.This paper presents the conceptual design of a boosting linac,static superconducting gantry and proton CT imaging equipment.The feasibility of energy enhancement is verified by simulation,and results from Geant4 simulations and reconstruction algorithms are presented,including the simulation verification of the advantage of the imaging mode.
基金supported by the Research collaboration on Thailand’s new synchrotron light source facility(SPS-II)(No.ANSO-CR-KP-2020-16).
文摘Proton computed tomography(CT)has a distinct practical significance in clinical applications.It eliminates 3–5%errors caused by the transformation of Hounsfield unit(HU)to relative stopping power(RSP)values when using X-ray CT for positioning and treatment planning systems(TPSs).Following the development of FLASH proton therapy,there are increased requirements for accurate and rapid positioning in TPSs.Thus,a new rapid proton CT imaging mode is proposed based on sparsely sampled projections.The proton beam was boosted to 350 MeV by a compact proton linear accelerator(LINAC).In this study,the comparisons of the proton scattering with the energy of 350 MeV and 230 MeV are conducted based on GEANT4 simulations.As the sparsely sampled information associated with beam acquisitions at 12 angles is not enough for reconstruction,X-ray CT is used as a prior image.The RSP map generated by converting the X-ray CT was constructed based on Monte Carlo simulations.Considering the estimation of the most likely path(MLP),the prior image-constrained compressed sensing(PICCS)algorithm is used to reconstruct images from two different phantoms using sparse proton projections of 350 MeV parallel proton beam.The results show that it is feasible to realize the proton image reconstruction with the rapid proton CT imaging proposed in this paper.It can produce RSP maps with much higher accuracy for TPSs and fast positioning to achieve ultra-fast imaging for real-time image-guided radiotherapy(IGRT)in clinical proton therapy applications.
文摘In civil aviation security screening, laptops, with their intricate structural composition, provide the potential for criminals to conceal dangerous items. Presently, the security process necessitates passengers to individually present their laptops for inspection. The paper introduced a method for laptop removal. By combining projection algorithms with the YOLOv7-Seg model, a laptop’s three views were generated through projection, and instance segmentation of these views was achieved using YOLOv7-Seg. The resulting 2D masks from instance segmentation at different angles were employed to reconstruct a 3D mask through angle restoration. Ultimately, the intersection of this 3D mask with the original 3D data enabled the successful extraction of the laptop’s 3D information. Experimental results demonstrated that the fusion of projection and instance segmentation facilitated the automatic removal of laptops from CT data. Moreover, higher instance segmentation model accuracy leads to more precise removal outcomes. By implementing the laptop removal functionality, the civil aviation security screening process becomes more efficient and convenient. Passengers will no longer be required to individually handle their laptops, effectively enhancing the efficiency and accuracy of security screening.
文摘We sought to determine the characteristics of viral specimens associated with fatal cases,asymptomatic cases and non-fatal symptomatic cases of COVID-19.This included the analysis of 1264 specimens found reactive for at least two SARS-CoV-2 specific loci from people screened for infection in Northern Nevada in March-May of 2020.Of these,30 were specimens from fatal cases,while 23 were from positive,asymptomatic cases.We assessed the relative amounts of SARS-CoV-2 RNA from sample swabs by real-time PCR and use of the threshold crossing value(Ct).Moreover,we compared the amount of human RNase P found on the same swabs.A considerably higher viral load was found to be associated with swabs from cases involving fatality and the difference was found to be strongly statistically significant.Noting this difference,we sought to assess whether any genetic correlation could be found in association with virus from fatal cases using whole genome sequencing.While no common genetic elements were discerned,one branch of epidemiologically linked fatal cases did have two point mutations,which no other of 156 sequenced cases from northern Nevada had.The mutations caused amino acid changes in the 3′-5′exonuclease protein,and the product of the gene,orf8.
基金the National Natural Science Foundation of China(Grant Nos.42090023,51734009 and 42002279)the Science Foundation of Key Laboratory of Shale Gas and Geoengineering,Institute of Geology and Geophysics,Chinese Academy of Sciences(Grant No.KLSG201708)。
文摘Soil-rock mixture(SRM),as a type of extremely heterogeneous geomaterial,is very common in nature and engineering.The fracture and damage of SRM often induce severe geological disasters.Hence,it is important to analyze the fracture evolution process of this material.In the present research,real-time computed tomography(CT)scanning was conducted on SRM and pure soil samples under uniaxial compressive experiments to investigate the influence of rocks on fracture evolution in SRM.The initiation of cracks,the original values of,and variations in,average density and heterogeneity in the soil matrix,the crack width evolution during loading,and the final failure modes were all studied.Cracks with a width greater than 0.1 mm will not arise until over 90%of ultimate stress is reached.In general,in SRM,areas where the initial average density of the soil matrix is smaller and the initial heterogeneity is greater,are much easier to crack,but the results for pure soil show the opposite effect.According to fracturing conditions shown in CT slices,fracturing and non-fracturing areas in the soil matrix were investigated.The average density of the soil matrix decreases in all areas under loading,except non-fracturing areas in SRM.For the whole sample,the increase in heterogeneity in the soil matrix of SRM is greater than that of pure soil;but for the fracturing areas,this increase in pure soil is greater.Besides,the average and standard deviations of crack width both follow logarithmic distributions with high correlation coefficients.
文摘目的应用循证医学Meta分析来评价CT和MRI对股骨头缺血坏死( avascular necrosis of the femoral head, ANFH)诊断的应用价值。方法检索cochrane图书馆(2011年第1期)、PubMed(1966~2011)、Embase(1989~2011)、中国生物医学文献数据库(1982~2011)、万方数据库(1982—2011),纳入国内外公开发表的关于股骨头缺血坏死的CT和MRI诊断的文献,按照纳入标准进行筛选,两名调查员独立对文献质量进行严格评价和资料提取,对符合标准的8篇文献在诊断ANFH方面使用软件Review mangager5.0进行Meta分析。结果共纳入8篇研究,共515例患者。Meta分析及其偏倚分歧提示MRI对股骨头缺血坏死阳性率的诊断价值高于CT,两者差别有显著统计学意义[OR=0.12(95%CI,0.04~0.33),P〈0.0001]。MRI对股骨头缺血坏死早期阳性率的诊断价值高于CT,两者差别有统计学意义[OR=0.45(95%CI,0.26~0.78),P=0.005]。结论MRI是首选的股骨头缺血坏死诊断手段,但仍需大样本随机对照试验来验证。