Tuning Second Chern Number in a Four-Dimensional Topological Insulator by High-Frequency Time-Periodic Driving

Floquet engineering has attracted considerable attention as a promising approach for tuning topological phase transitions.We investigate the effects of high-frequency time-periodic driving in a four-dimensional(4D)topological insulator,focusing on topological phase transitions at the off-resonant quasienergy gap.The 4D topological insulator hosts gapless three-dimensional boundary states,characterized by the second Chern number C_(2).We demonstrate that the second Chern number of 4D topological insulators can be modulated by tuning the amplitude of time-periodic driving.This includes transitions from a topological phase with C_(2)=±3 to another topological phase with C_(2)=±1,or to a topological phase with an even second Chern number C_(2)=±2,which is absent in the 4D static system.Finally,the approximation theory in the high-frequency limit further confirms the numerical conclusions.

Higher-order topological Anderson insulator on the Sierpiński lattice

Disorder effects on topological materials in integer dimensions have been extensively explored in recent years. However, its influence on topological systems in fractional dimensions remains unclear. Here, we investigate the disorder effects on a fractal system constructed on the Sierpiński lattice in fractional dimensions. The system supports the second-order topological insulator phase characterized by a quantized quadrupole moment and the normal insulator phase. We find that the second-order topological insulator phase on the Sierpiński lattice is robust against weak disorder but suppressed by strong disorder. Most interestingly, we find that disorder can transform the normal insulator phase to the second-order topological insulator phase with an emergent quantized quadrupole moment. Finally, the disorder-induced phase is further confirmed by calculating the energy spectrum and the corresponding probability distributions.

双丹明目胶囊对糖尿病大鼠模型视网膜VEGF家族表达的影响

目的:观察双丹明目胶囊对糖尿病大鼠模型视网膜VEGF家族因子VEGF-a、VEGF-b、VEGF-c蛋白表达的影响。方法:将40只雄性SD大鼠,采用随机数字法分为A空白组、B模型组、C双丹明目组、D阳性对照组4组,每组10只20眼。将B、C、D三组实验大鼠采用STZ 50mg/kg的剂量一次性大鼠尾静脉注射法建立糖尿病视网膜病变大鼠模型,造模后1wk开始连续灌胃用药,灌胃后4wk,处死动物,免疫组化法检测视网膜组织中VEGF-a、VEGF-b、VEGF-c的表达。结果:成模后用药第4wk,模型组、双丹明目组、阳性对照组视网膜中VEGF-a、VEGF-b、VEGF-c蛋白表达平均灰度值均低于正常组,平均光密度均高于正常组,其中模型组与正常组比较,差异均具有统计学意义(P<0. 01);双丹明目组、阳性对照组VEGF-a、VEGF-b、VEGF-c表达的平均灰度值均高于模型组(P<0. 05),平均光密度值均低于模型组(P<0. 01)。结论:双丹明目胶囊能明显降低VEGF家族中VEGF-a、VEGF-b、VEGF-c在糖尿病模型大鼠视网膜中的表达,对其视网膜有一定的保护作用。

双丹明目胶囊对糖尿病大鼠模型视网膜VEGF-a、VEGF-b、VEGF-c及其受体Flk-1表达的影响（英文）

目的观察双丹明目胶囊对糖尿病大鼠模型视网膜VEGF-a、VEGF-b、VEGF-c及其受体Flk-1表达的影响。方法将40只SD大鼠,采用随机数字法分为空白组(A)、模型组(B)、双丹明目组(C)、阳性对照组(D) 4组,每组10只20眼。将B、C、D三组实验大鼠采用STZ 50mg/kg的剂量一次性大鼠尾静脉注射法建立糖尿病视网膜病变大鼠模型,造模后1周开始连续灌胃用药,灌胃后8周,处死动物,采用免疫组化法检测视网膜组织中VEGF-a、VEGF-b、VEGF-c及其受体Flk-1的表达。结果成模后用药第8周,模型组、双丹明目组、阳性对照组视网膜中VEGF-a、VEGF-b、VEGF-c及其受体Flk-1蛋白表达平均灰度值均低于正常组,平均光密度均高于正常组,其中:模型组与正常组比较,差异均具有统计学意义(P<0.01);双丹明目组、阳性对照组VEGF-a、VEGF-b、VEGF-c及其受体Flk-1表达的平均灰度值均高于模型组、平均光密度值均低于模型组(P<0.05或P<0.01)。结论双丹明目胶囊能明显降低VEGF-a、VEGF-b、VEGF-c及其受体Flk-1在糖尿病模型大鼠视网膜中的表达,对其视网膜有一定的保护作用。

Risk factors for post-hepatectomy liver failure in 80 patients

BACKGROUND Post-hepatectomy liver failure(PHLF)is a serious complication and a leading cause of death after hepatectomy,an accurate prediction of PHLF is important for improvement of prognosis after hepatectomy.AIM To retrospectively analyze the risk factors for postoperative liver failure in patients undergoing hepatectomy for liver tumors.METHODS The clinical data of 80 patients undergoing hepatectomy in our hospital from June 2018 to January 2020 were collected.With laboratory examination as well as preand post-operative abdominal three-dimensional reconstructive computed tomography,the demographic data,surgical data,biochemical indicators,coagulation index,routine blood tests,spleen and liver volumes,relative remnant liver volume,and other related indicators were obtained and compared between patients with PHLF and those without PHLF.RESULTS PHLF occurred in 19(23.75%)patients.Univariate logistic regression analysis showed that gender,history of hepatitis/cirrhosis,and preoperative bilirubin,albumin,coagulation function,albumin-bilirubin ratio,aspartate aminotransferase-to-platelet ratio index(APRI),Model for End-Stage Liver Disease score,spleen volume(SV),spleen volume/liver volume ratio(SV/LV),and relative remnant liver volume were statistically associated with the occurrence of PHLF(all P<0.05).Multivariate regression analysis showed that preoperative total bilirubin,platelets(PLT),APRI,and SV/LV were independent risk factors for PHLF(all P<0.05).The area under the curve and cut-off values were 0.787 and 18.6 mmol/L for total bilirubin,0.893 and 146×1012/L for PLT,0.907 and 0.416 for APRI,and 0.752 and 20.84%for SV/LV,respectively.CONCLUSION For patients undergoing liver resection,preoperative total bilirubin,PLT,APRI,and SV/LV are independent risk factors for PHLF.These findings may provide guidance to safely perform liver surgery in such patients.

Efficacy and safety of percutaneous transhepatic biliary radiofrequency ablation in patients with malignant obstructive jaundice

BACKGROUND Percutaneous transhepatic cholangiodrainage(PTCD)and endoscopic retrograde cholangiopancreatography/endoscopic nasobiliary drainage are the most common clinical procedures for jaundice control in patients with unresectable malignant obstructive jaundice,yet the safety and effect of endobiliary radiofrequency ablation(EB-RFA)combined PTCD is rarely reported,in this article,we report our experience of EB-RFA combined PTCD in such patients.AIM To retrospectively study the efficacy and safety of EB-RFA combined PTCD in patients with unresectable malignant obstructive jaundice.METHODS Patients with unresectable malignant obstructive jaundice treated with EB-RFA under PTCD were selected,the bile ducts of the right posterior lobe was selected as the target bile ducts in all cases.The general conditions of all patients,preoperative tumour markers,total bilirubin(TBIL),direct bilirubin(DBIL),albumin(ALB),alkaline phosphatase(ALP),and glutamyl transferase(GGT)before and on the 7th day after the procedure,as well as perioperative complications,stent patency time and patient survival were recorded.RESULTS All patients successfully completed the operation,TBIL and DBIL decreased significantly in all patients at the 7th postoperative day(P=0.009 and 0.006,respectively);the values of ALB,ALP and GGT also decreased compared with the preoperative period,but the difference was not statistically significant.Perioperative biliary bleeding occurred in 2 patients,which was improved after transfusion of blood and other conservative treatments,pancreatitis appeared in 1 patient after the operation,no serious complication and death happened after operation.Except for 3 patients with loss of visits,the stent patency rate of the remaining 14 patients was 100%71%and 29%at the 1^(st),3^(rd),and 6^(th)postoperative months respectively,with a median survival of 4 months.CONCLUSION EB-RFA under PTCD in patients with unresectable malignant obstructive jaundice has a satisfactory therapeutic effect and high safety,which is worthy of further clinical practice.