AIM: To describe a three-dimensional model(3DM) to accurately reconstruct anatomic relationships of centrally located hepatocellular carcinomas(HCCs).METHODS: From March 2013 to July 2014, reconstructions and visual s...AIM: To describe a three-dimensional model(3DM) to accurately reconstruct anatomic relationships of centrally located hepatocellular carcinomas(HCCs).METHODS: From March 2013 to July 2014, reconstructions and visual simulations of centrally located HCCs were performed in 39 patients using a 3D subject-based computed tomography(CT) model with customdeveloped software. CT images were used for the 3D reconstruction of Couinaud's pedicles and hepatic veins, and the calculation of corresponding tumor territories and hepatic segments was performed using Yorktal DMIT software. The respective volume, surgical margin, and simulated virtual resection of tumors were also estimated by this model preoperatively. All patients were treated surgically and the results were retrospectively assessed. Clinical characteristics, imaging data, procedure variables, pathologic features, and postoperative data were recorded and compared to determine the reliability of the model.RESULTS: 3D reconstruction allowed stereoscopic identification of the spatial relationships between physiologic and pathologic structures, and offered quantifiable liver resection proposals based on individualized liver anatomy. The predicted values were consistent with the actual values for tumor mass volume(82.4 ± 109.1 m L vs 84.1 ± 108.9 m L, P = 0.910), surgical margin(10.1 ± 6.2 mm vs 9.1 ± 5.9 mm, P = 0.488), and maximum tumor diameter(4.61 ± 2.16 cm vs 4.53 ± 2.14 cm, P = 0.871). In addition,the number and extent of portal venous ramifications, as well as their relation to hepatic veins, were visualized. Preoperative planning based on simulated resection facilitated complete resection of large tumors located in the confluence of major vessels. And most of the predicted data were correlated with intraoperative findings.CONCLUSION: This 3DM provides quantitative morphometry of tumor masses and a stereo-relationship with adjacent structures, thus providing a promising technique for the management of centrally located HCCs.展开更多
Centrally located hepatocellular carcinoma(HCC)is sited in the central part of the liver and adjacent to main hepatic vascular structures.This special location is associated with an increase in the difficulty of surge...Centrally located hepatocellular carcinoma(HCC)is sited in the central part of the liver and adjacent to main hepatic vascular structures.This special location is associated with an increase in the difficulty of surgery,aggregation of the recurrence disease,and greater challenge in disease management.This review summarizes the evolution of our understanding for centrally located HCC and discusses the development of treatment strategies,surgical approaches and recurrence prevention methods.To improve patient survival,a multi-disciplinary modality is greatly needed throughout the whole treatment period.展开更多
In recent years,the issue of aircraft icing has gained widespread recognition.The breaking and detachment of dynamic ice can pose a threat to flight safety.However,the shedding and fracture mechanisms of dynamic ice a...In recent years,the issue of aircraft icing has gained widespread recognition.The breaking and detachment of dynamic ice can pose a threat to flight safety.However,the shedding and fracture mechanisms of dynamic ice are unclear and cannot meet the engineering needs of ice-shedding hazard assessment.Therefore,studying the fracture toughness of ice bodies has extremely important practical significance.To address this issue,this article uses a centrally cracked Brazilian disk(CCBD)specimen to measure the pure modeⅠtoughness and pure modeⅡfracture toughness of freshwater ice at different loading rates.The mixed-mode(Ⅰ–Ⅱ)fracture characteristics of ice are discussed,and the experimental results are compared and analyzed with the theoretical values of the generalized maximum tangential stress(GMTS)criterion considering the influence of T-stress.The results indicated that as the loading rate increases,the pure modeⅠtoughness and pure modeⅡfracture toughness of freshwater ice decrease,and the fracture toughness of freshwater ice is more sensitive to the loading rate.Ⅰn terms of fracture criteria,the theoretical value of the ratio of pure modeⅡfracture toughness to pure modeⅠfracture toughness based on the GMTS criterion is in good agreement with the experimental value,while the theoretical value based on the maximum tangential stress(MTS)criterion deviates significantly from the experimental value,indicating that the GMTS criterion considering the influence of T-stress can better predict the experimental results.展开更多
Element a in ring R is called centrally clean if it is the sum of central idempotent e and unit u.Moreover,a=e+u is called a centrally clean decomposition of a and R is called a centrally clean ring if every element o...Element a in ring R is called centrally clean if it is the sum of central idempotent e and unit u.Moreover,a=e+u is called a centrally clean decomposition of a and R is called a centrally clean ring if every element of R is centrally clean.First,some characterizations of centrally clean elements are given.Furthermore,some properties of centrally clean rings,as well as the necessary and sufficient conditions for R to be a centrally clean ring are investigated.Centrally clean rings are closely related to the central Drazin inverses.Then,in terms of centrally clean decomposition,the necessary and sufficient conditions for the existence of central Drazin inverses are presented.Moreover,the central cleanness of special rings,such as corner rings,the ring of formal power series over ring R,and a direct product ∏ R_(α) of ring R_(α),is analyzed.Furthermore,the central group invertibility of combinations of two central idempotents in the algebra over a field is investigated.Finally,as an application,an example that lists all invertible,central group invertible,group invertible,central Drazin invertible elements,and centrally clean elements of the group ring Z_(2)S_(3) is given.展开更多
AIM:To determine the influence of gaps[places where neither the donor's nor the recipient's Descemet's membrane(DM)is present]and overlaps(places where the recipient's DM is covered by the donor's ...AIM:To determine the influence of gaps[places where neither the donor's nor the recipient's Descemet's membrane(DM)is present]and overlaps(places where the recipient's DM is covered by the donor's DM)on the frequency of postoperative detachment of DM endothelial keratoplasty(DMEK)lamellae.METHODS:Totally 64 eyes of 64 patients with Fuchs'endothelial dystrophy or bullous keratopathy indicated for DMEK were randomly divided in two groups.The diameter of the implanted DMEK lamella was the same in both groups(8 mm),but we changed the diameter of the removed recipient DM.In the first group(32 eyes),the circular area was approximately 8.5 mm(gaps);in the second group(32 eyes),the diameter was 7.5 mm(overlaps).Postoperatively we noted all cases of detachment visible on the slit lamp and these cases we indicated for rebubbling.We also measured the uncorrected distance visual acuity(UDVA)as well as corrected distance visual acuity(CDVA)in decimal and postoperative endothelial cell density(ECD).The minimum follow-up time was 6mo.RESULTS:The number of rebubbling procedures in the entire group of patients was 13,i.e.,20.3%,with 6 eyes(18.7%)in the gap group,and 7 eyes(21.9%)in the overlap group.Lamella replacement(re-DMEK)was required in 3(gap group)and 2 patients(overlap group),respectively.The dif ference between the groups was statistically insignificant.The UDVA was 0.54±0.21 in the gap group and 0.58±0.24 in the overlap group.The CDVA was 0.74±0.22 and 0.80±0.16,respectively.ECD was 1920±491 and 2149±570 cells/mm2.The small differences between both groups were not statistically significant.CONCLUSION:We do not notice any difference in the group of patients with overlaps or gaps of DM.The presence of small areas of gaps or overlaps does not affect the frequency of detachment of the DMEK lamellae.展开更多
文摘AIM: To describe a three-dimensional model(3DM) to accurately reconstruct anatomic relationships of centrally located hepatocellular carcinomas(HCCs).METHODS: From March 2013 to July 2014, reconstructions and visual simulations of centrally located HCCs were performed in 39 patients using a 3D subject-based computed tomography(CT) model with customdeveloped software. CT images were used for the 3D reconstruction of Couinaud's pedicles and hepatic veins, and the calculation of corresponding tumor territories and hepatic segments was performed using Yorktal DMIT software. The respective volume, surgical margin, and simulated virtual resection of tumors were also estimated by this model preoperatively. All patients were treated surgically and the results were retrospectively assessed. Clinical characteristics, imaging data, procedure variables, pathologic features, and postoperative data were recorded and compared to determine the reliability of the model.RESULTS: 3D reconstruction allowed stereoscopic identification of the spatial relationships between physiologic and pathologic structures, and offered quantifiable liver resection proposals based on individualized liver anatomy. The predicted values were consistent with the actual values for tumor mass volume(82.4 ± 109.1 m L vs 84.1 ± 108.9 m L, P = 0.910), surgical margin(10.1 ± 6.2 mm vs 9.1 ± 5.9 mm, P = 0.488), and maximum tumor diameter(4.61 ± 2.16 cm vs 4.53 ± 2.14 cm, P = 0.871). In addition,the number and extent of portal venous ramifications, as well as their relation to hepatic veins, were visualized. Preoperative planning based on simulated resection facilitated complete resection of large tumors located in the confluence of major vessels. And most of the predicted data were correlated with intraoperative findings.CONCLUSION: This 3DM provides quantitative morphometry of tumor masses and a stereo-relationship with adjacent structures, thus providing a promising technique for the management of centrally located HCCs.
文摘Centrally located hepatocellular carcinoma(HCC)is sited in the central part of the liver and adjacent to main hepatic vascular structures.This special location is associated with an increase in the difficulty of surgery,aggregation of the recurrence disease,and greater challenge in disease management.This review summarizes the evolution of our understanding for centrally located HCC and discusses the development of treatment strategies,surgical approaches and recurrence prevention methods.To improve patient survival,a multi-disciplinary modality is greatly needed throughout the whole treatment period.
基金supported by the National Natural Science Foundation of China(Nos.12132019 and 11872042)the Open Fund for Key Laboratory of Deep Underground Science and Engineering of Ministry of Education(No.DESEYU202301)+1 种基金the 2023 Open Project of Failure Mechanics and Engineering Disaster Prevention,Key Lab of Sichuan Province(No.FMEDP202306)the Natural Science Foundation of Sichuan Province(No.2023NSFSC0043).
文摘In recent years,the issue of aircraft icing has gained widespread recognition.The breaking and detachment of dynamic ice can pose a threat to flight safety.However,the shedding and fracture mechanisms of dynamic ice are unclear and cannot meet the engineering needs of ice-shedding hazard assessment.Therefore,studying the fracture toughness of ice bodies has extremely important practical significance.To address this issue,this article uses a centrally cracked Brazilian disk(CCBD)specimen to measure the pure modeⅠtoughness and pure modeⅡfracture toughness of freshwater ice at different loading rates.The mixed-mode(Ⅰ–Ⅱ)fracture characteristics of ice are discussed,and the experimental results are compared and analyzed with the theoretical values of the generalized maximum tangential stress(GMTS)criterion considering the influence of T-stress.The results indicated that as the loading rate increases,the pure modeⅠtoughness and pure modeⅡfracture toughness of freshwater ice decrease,and the fracture toughness of freshwater ice is more sensitive to the loading rate.Ⅰn terms of fracture criteria,the theoretical value of the ratio of pure modeⅡfracture toughness to pure modeⅠfracture toughness based on the GMTS criterion is in good agreement with the experimental value,while the theoretical value based on the maximum tangential stress(MTS)criterion deviates significantly from the experimental value,indicating that the GMTS criterion considering the influence of T-stress can better predict the experimental results.
基金The National Natural Science Foundation of China(No.12171083,11871145,12071070)the Qing Lan Project of Jiangsu Province。
文摘Element a in ring R is called centrally clean if it is the sum of central idempotent e and unit u.Moreover,a=e+u is called a centrally clean decomposition of a and R is called a centrally clean ring if every element of R is centrally clean.First,some characterizations of centrally clean elements are given.Furthermore,some properties of centrally clean rings,as well as the necessary and sufficient conditions for R to be a centrally clean ring are investigated.Centrally clean rings are closely related to the central Drazin inverses.Then,in terms of centrally clean decomposition,the necessary and sufficient conditions for the existence of central Drazin inverses are presented.Moreover,the central cleanness of special rings,such as corner rings,the ring of formal power series over ring R,and a direct product ∏ R_(α) of ring R_(α),is analyzed.Furthermore,the central group invertibility of combinations of two central idempotents in the algebra over a field is investigated.Finally,as an application,an example that lists all invertible,central group invertible,group invertible,central Drazin invertible elements,and centrally clean elements of the group ring Z_(2)S_(3) is given.
文摘AIM:To determine the influence of gaps[places where neither the donor's nor the recipient's Descemet's membrane(DM)is present]and overlaps(places where the recipient's DM is covered by the donor's DM)on the frequency of postoperative detachment of DM endothelial keratoplasty(DMEK)lamellae.METHODS:Totally 64 eyes of 64 patients with Fuchs'endothelial dystrophy or bullous keratopathy indicated for DMEK were randomly divided in two groups.The diameter of the implanted DMEK lamella was the same in both groups(8 mm),but we changed the diameter of the removed recipient DM.In the first group(32 eyes),the circular area was approximately 8.5 mm(gaps);in the second group(32 eyes),the diameter was 7.5 mm(overlaps).Postoperatively we noted all cases of detachment visible on the slit lamp and these cases we indicated for rebubbling.We also measured the uncorrected distance visual acuity(UDVA)as well as corrected distance visual acuity(CDVA)in decimal and postoperative endothelial cell density(ECD).The minimum follow-up time was 6mo.RESULTS:The number of rebubbling procedures in the entire group of patients was 13,i.e.,20.3%,with 6 eyes(18.7%)in the gap group,and 7 eyes(21.9%)in the overlap group.Lamella replacement(re-DMEK)was required in 3(gap group)and 2 patients(overlap group),respectively.The dif ference between the groups was statistically insignificant.The UDVA was 0.54±0.21 in the gap group and 0.58±0.24 in the overlap group.The CDVA was 0.74±0.22 and 0.80±0.16,respectively.ECD was 1920±491 and 2149±570 cells/mm2.The small differences between both groups were not statistically significant.CONCLUSION:We do not notice any difference in the group of patients with overlaps or gaps of DM.The presence of small areas of gaps or overlaps does not affect the frequency of detachment of the DMEK lamellae.
