Objective:To investigate the radiation field distribution characteristics in a 9 MeV electron FLASH (e-FLASH) linear accelerator treatment room.Methods:The Geant4 Monte Carlo program was employed for physical simulating of the radiation field distribution inside and outside the treatment room under a single-beam delivery condition with a total dose of 50 Gy at the reference point and a dose rate of 250 Gy/s. High-sensitivity radiation detectors (AT1123) were used to validate the measurements at key points.Results:The dose rate at the reference point was approximately 9×10 11 μSv/h. Due to the scattering and shielding effects, the deviation of the attenuation rate from the inverse-square law was observed and the isodose lines exhibited spatial drift. Measured dose rates at key points showed good agreement with the simulation result, with a maximum deviation within 30%. Conclusions:The complex radiation field distribution can be effectively simulated using Geant4 in an e-FLASH treatment room. This indicated the Geant4 is not only applicable for the shielding calculations in e-FLASH radiotherapy facilities, but also for the design optimization through, reduction of trial-and-error iterations and engineering costs.

Objective To explore the effects of home-based exercise rehabilitation on cardiac structure, valvular function, and exercise capacity in patients with severe aortic stenosis (AS) after transcatheter aortic valve replacement (TAVR). Methods 49 patients with severe AS who underwent TAVR at Zhongshan Hospital, Fudan University, from January 2024 to February 2025 were enrolled. They were divided into an exercise group (n＝25) or a non-exercise group (n＝24) based on participating or not in home-based rehabilitation after TAVR. The exercise group received 12 weeks of home-based exercise training (aerobic exercise plus resistance training every week); the non-exercise group received routine care. Transthoracic echocardiography (TTE) was used to assess cardiac structural parameters before discharge (T0) and after 12 weeks of exercise (T1). Functional outcomes including the 6-minute walk test (6MWT), Duke Activity Status Index (DASI), and Short Physical Performance Battery (SPPB) were compared between the two groups. A linear mixed-effects model was used to analyze the effect of home-based rehabilitation on echocardiographic parameters. Patients were stratified by baseline 6MWT (＜240 m as low-function subgroup, ≥240 m as high-function subgroup) to compare exercise-related outcomes between subgroups. Results At T1, the exercise group had a longer 6MWT distance than the non-exercise group (P＝0.012). The linear mixed-effects model showed that after 12 weeks of exercise, the left ventricular end-diastolic diameter (LVEDD) decreased in the exercise group but slightly increased in the non-exercise group, with a significant difference in changes over time between the two groups (P_interaction＝0.030). The exercise group also showed greater improvement in effective orifice area index (P_interaction＝0.028) and effective orifice area (P_interaction＝0.042) than the non-exercise group. Subgroup analysis revealed that in the low-function subgroup, the exercise group showed greater improvement in the 6MWT (P_interaction＝0.035) and the effective orifice area index (P_interaction＝0.046) compared to the non-exercise group; in the high-function subgroup, the exercise group showed greater improvement only in LVEDD compared to the non-exercise group (P_interaction＝0.046). Conclusions Home-based exercise rehabilitation improves exercise capacity, optimizes left ventricular remodeling, and enhances valvular function in patients with severe AS after TAVR, with greater benefits observed in patients with lower baseline 6MWT.

Objective To compare the effect of transcranial direct current stimulation(tDCS),functional electrical stimulation(FES)of the forearm flexors,and their combined intervention on grip strength and cerebral cortical activation in healthy young adults.Methods From December,2024 to March,2025,twelve healthy right-handed young volunteers aged 20 to 23 years were recruited from the Fifth Hospital of Xiamen.They were randomly assigned to receive tDCS alone(tDCS group),FES alone(FES group),or simultaneous tDCS-FES(Sim group)in a crossover design.For tDCS,synchronous bihemispheric stimulation of the primary motor cortex(M1)was applied(anode on the left/cathode on the right).FES was delivered to the right flexor carpi radialis and flexor digitorum superficialis muscles.Isometric maximal grip strength was measured before and after each intervention,and functional near-infrared spectroscopy(fNIRS)was used to synchronously monitor oxyhemoglobin(HbO2)during grip strength tasks.Results A case dropped down.The effect of time on grip strength was significant(F=3.964,P=0.048);Post-hoc tests revealed that grip strength significantly increased after intervention in both FES group and Sim group(P<0.05).The effect of groups was significant on HbO2 of the left prefrontal cortex(PFC)and left premotor and supplemen-tary motor cortex(PMC)(F>3.613,P<0.05);Post-hoc tests revealed that the HbO2 of the left PFC and left pri-mary sensory cortex was higher in FES group than in Sim group,while the HbO2 of the left PMC and right PMC was higher in tDCS group than in Sim group(all P<0.05).Correlation analysis indicated that the grip strength was positively correlated with the HbO2 of the bilateral M1 only in Sim group(r>0.694,P<0.05).Conclusion For healthy young adults,tDCS alone mainly activates motor-related brain regions such as PFC and PMC,while FES alone directly enhances peripheral muscle force output and activates the left PFC to participate in mo-tor regulation.The combined intervention achieves the maximum gain in grip strength through a brain-limb inte-grated regulation mechanism,which may be associated with optimization of neural resource and M1 activity.

Objective To compare the effect of transcranial direct current stimulation(tDCS),functional electrical stimulation(FES)of the forearm flexors,and their combined intervention on grip strength and cerebral cortical activation in healthy young adults.Methods From December,2024 to March,2025,twelve healthy right-handed young volunteers aged 20 to 23 years were recruited from the Fifth Hospital of Xiamen.They were randomly assigned to receive tDCS alone(tDCS group),FES alone(FES group),or simultaneous tDCS-FES(Sim group)in a crossover design.For tDCS,synchronous bihemispheric stimulation of the primary motor cortex(M1)was applied(anode on the left/cathode on the right).FES was delivered to the right flexor carpi radialis and flexor digitorum superficialis muscles.Isometric maximal grip strength was measured before and after each intervention,and functional near-infrared spectroscopy(fNIRS)was used to synchronously monitor oxyhemoglobin(HbO2)during grip strength tasks.Results A case dropped down.The effect of time on grip strength was significant(F=3.964,P=0.048);Post-hoc tests revealed that grip strength significantly increased after intervention in both FES group and Sim group(P<0.05).The effect of groups was significant on HbO2 of the left prefrontal cortex(PFC)and left premotor and supplemen-tary motor cortex(PMC)(F>3.613,P<0.05);Post-hoc tests revealed that the HbO2 of the left PFC and left pri-mary sensory cortex was higher in FES group than in Sim group,while the HbO2 of the left PMC and right PMC was higher in tDCS group than in Sim group(all P<0.05).Correlation analysis indicated that the grip strength was positively correlated with the HbO2 of the bilateral M1 only in Sim group(r>0.694,P<0.05).Conclusion For healthy young adults,tDCS alone mainly activates motor-related brain regions such as PFC and PMC,while FES alone directly enhances peripheral muscle force output and activates the left PFC to participate in mo-tor regulation.The combined intervention achieves the maximum gain in grip strength through a brain-limb inte-grated regulation mechanism,which may be associated with optimization of neural resource and M1 activity.

Objective:To investigate the radiation field distribution characteristics in a 9 MeV electron FLASH (e-FLASH) linear accelerator treatment room.Methods:The Geant4 Monte Carlo program was employed for physical simulating of the radiation field distribution inside and outside the treatment room under a single-beam delivery condition with a total dose of 50 Gy at the reference point and a dose rate of 250 Gy/s. High-sensitivity radiation detectors (AT1123) were used to validate the measurements at key points.Results:The dose rate at the reference point was approximately 9×10 11 μSv/h. Due to the scattering and shielding effects, the deviation of the attenuation rate from the inverse-square law was observed and the isodose lines exhibited spatial drift. Measured dose rates at key points showed good agreement with the simulation result, with a maximum deviation within 30%. Conclusions:The complex radiation field distribution can be effectively simulated using Geant4 in an e-FLASH treatment room. This indicated the Geant4 is not only applicable for the shielding calculations in e-FLASH radiotherapy facilities, but also for the design optimization through, reduction of trial-and-error iterations and engineering costs.

Objective:To investigate the relationship between Watchman occluder and structure of mitral valve apparatus in patients with nonvalvular atrial fibrillation after left atrial appendage closure(LAAC) by transesophageal echocardiography.Methods:From January 2018 to December 2020, 29 patients [20 male, 9 female, (69.55±10.06)years old] with nonvalvular atrial fibrillation underwent LAAC in Zhongshan Hospital (implanted Watchman occluder), and all patients underwent pre-operative and follow-up two and three dimensional transesophageal echocardiography(2DTEE, 3DTEE) at 60 days after the operation. The quantitative parameters of mitral valve apparatus were obtained by offline analysis using the MVA module in QLab 13.0 (Philips Healthcare, Andover, MA), the differences between pre-operation and post-operation were compared, and the relationship between occluder compression ratio and mitral valve parameters with significant changes after operation was analyzed.Results:①The values of AL-PM diameter(AL-PM), 3D annulus circumference(3DAC), 2D annulus area(2DAA), 3D annulus area(3DAA), tenting volume(TnV), tenting area(TnA) and commissural diameter(CD) decreased significantly compared with pre-operative values(all P<0.05), while the annulus sphericity index(SPI) increased significantly ( P<0.05). ②In the quantitative mitral value parameters with significant pre- and post-operation changes, TnV was correlated with the occluder compression ratio ( r=0.403, P=0.030), but AL-PM, SPI, 3DAC, 2DAA, 3DAA, TnA, CD were not correlated with it(all P>0.05). Conclusions:3DTEE can accurately evaluate the effect of Watchman occluder on the morphology of mitral valve device. Implanting Watchman occluder in left atrial appendage can make three-dimensional mitral valve apparatus flat and decrease annulus left-right diameter and annulus area; the pre-operative TnV, the more susceptible to the occluder implantation, and TnV is correlated with the compression ratio.

Objective To study the expression of silent information regulator (SIRT) in brains of rats with chronic fluorosis and reveal the correlation between SIRT1 and the ability of learning and memory of rats.Methods Sixty SD rats were selected and their body weight was (100 ± 20) g,according to the body mass of the rats,random number table method was used to divide rats into control group,low and high fluoride groups,experimental period was 3 and 6 months (ten rats in each experimental period,half males and half females).In control group,the rats were fed with drinking water containing no more than 0.5 mg/L fluoride;the rats in low and high fluoride groups were fed drinking water containing 5.0 and 50.0 mg/L fluoride,respectively.All of rats were fed the same standard food containing no more than 0.6 mg/kg fluoride.Three degree method was used to check the formation of dental fluorosis.Rat urinary fluoride was determined via the fluoride electrode method;Morris water maze method was used to detect the ability of learning and memory of rats (the escape latency time,the number of crossing the platform and stay time in platform quadrant);the protein and mRNA expression levels of SIRT1 were detected by Western blotting and Real-time PCR,respectively.Results In the experimental period of 3 and 6 months,no dental fluorosis was observed of rats in control group,but there were different degrees of dental fluorosis in low and high fluoride groups,especially in high fluoride group.The urinary fluorine contents [(1.60 ± 0.09),(1.91 ± 0.16) mg/L;(1.94 ± 0.19),(2.31 ± 0.18) mg/L] of rats fed with low and high fluoride for 3 or 6 months were significantly higher than those in control group [(1.08 ± 0.15),(1.09 ± 0.17) mg/L,P ＜ 0.05].The escape latency time [(18.36 ± 2.80) s] of rats in the high fluoride group at the end of 3 months was higher than that of control group [(6.68 ± 3.01) s,P ＜ 0.05],the number of stay time in platform quadrant [(12.91 ± 3.25) s] was lower than that of control group [(19.97 ± 3.30) s,P ＜ 0.05].The escape latency time [(15.46 ± 4.56),(28.16 ± 4.00) s] of rats in low and high fluoride groups at the end of 6 months were all higher than that of control group [(6.62 ± 2.31) s,P ＜ 0.05];the number of crossing the platform and stay time in platform quadrant [(2.25 ± 1.71) times,(12.73 ± 3.55) s;(1.40 ± 1.15) times,(9.26 ± 1.72) s] of these rats were significantly lower than those of the control group [(4.00 ± 1.58) times,(19.53 ± 4.36) s,P ＜ 0.05].The expression levels of protein [(73.84 ± 9.68)％,(73.23 ± 4.51)％;(53.30 ± 17.63)％,(54.69 ± 18.71)％] and mRNA [(70.33 ± 4.89)％,(66.27 ± 3.38)％;(37.72 ± 4.89)％,(44.15 ± 1.74)％] of SIRT1 in the hippocampus and cortex of rats fed with high fluoride for 3 or 6 months were significantly lower than those in control group [(100.00 ± 13.51)％,(100.00 ± 13.60)％;(100.00 ± 15.37)％,(100.00 ± 12.19)％;(100.00 ± 2.65)％,(100.00 ± 4.34)％;(100.00 ± 3.40)％,(100.00 ± 4.52)％,P ＜ 0.05].Whereas,the decreased expression levels of protein [(77.65 ± 14.51)％,(71.51 ± 8.27)％] and mRNA [(57.78 ± 1.96)％,(63.76 ± 2.16)％] of SIRT1 in the hippocampus and cortex of rats in the low fluoride group were only observed at the end of 6 month of experiment (P ＜ 0.05).The expression of protein of SIRT1 in the hippocampus and cortex of rats in 3 or 6 months was negatively correlated with the escape latency time of rats (r=-0.598 5,-0.493 2;-0.782 6,-0.777 3,P＜ 0.05),and it was positively correlated with the number of crossing the platform (r =0.547 7,0.523 3;0.720 5,0.715 4,P ＜ 0.05).Conclusion The decrease of the ability of learning and memory in rats with chronic fluorosis may be related to the decreased expression of SIRT1 influenced by chronic fluorosis.

Objective To detect the expression of peroxisome proliferator-activated receptor γ (PPARγ) in the brains of rats with chronic fluorosis and elucidate the relationship between PPARγand oxidative stress in chronic fluorosis.Methods According to body weight (100-120 g),sixty healthy SD rats were divided into control group (less than 0.5 mg/L fluoride in drinking water),low fluoride group (5.0 mg/L fluoride in drinking water,prepared by NaF),and high fluoride group (50.0 mg/L fluoride in drinking water) via the random number table method,20 rats in each group (half male and half female).The experiment periods were 3 and 6 months,respectively.Then 24-hour urine samples of rats were collected from each group,all rats were put to death and brain tissues were taken.The fluoride contents in urine and brain tissue were measured with fluoride-ion selective electrode;the levels of PPARγ protein and mRNA in the cortex and hippocampus were determined by Western blotting and Real-time fluorescence quantitative PCR,respectively;and the activities of superoxide dismutase (SOD) and level of malondialdehyde (MDA) in serum were detected by xanthine oxidase method and thiobarbituric acid method;the correlation between PPARγ protein expression and oxidative stress was analyzed.Results After 3 and 6 months of treatment,the contents of fluoride in urine and brain in low fluoride group [(1.57 ± 0.18) mg/L,(3.43 ± 0.70) μg/g;(1.79 ± 0.17) mg/L,(7.40 ± 1.21) μg/g] were higher than those of control group [(1.11 ± 0.17) mg/L,(2.39 ± 0.50) μg/g;(1.02 ± 0.15) mg/L,(2.87 ± 0.82) μg/g,P ＜ 0.05],and the values in high fluoride group [(1.91 ± 0.23) mg/L,(6.70 ± 0.87) μg/g;(2.44 ± 0.51) mg/L,(12.10 ± 1.30) μg/g] were significantly higher than those in low fluoride group (P ＜ 0.05).In high fluoride group after 3 months of treatment,the expression of PPARγprotein [(79.00 ± 3.46)％,(80.35 ± 2.50)％] and mRNA [(79.11 ± 11.18)％,(82.10 ± 9.94)％] in hippocampus and cortex of rat brains were significantly lower than those of low fluoride group [(104.01 ± 5.77)％,(101.17 ± 6.35)％;(112.88 ± 22.15)％,(101.14 ± 8.60)％,P＜ 0.05];the expression of PPARγprotein [(64.32 ± 10.43)％,(60.20 ± 10.92)％] and mRNA [(41.03 ± 9.93)％,(52.25 ± 11.48)％] in the same brain regions of the rats after 6 months of treatment in high fluoride group were significantly lower than those of control group [(99.99 ± 11.19)％,(100.00 ± 11.30)％;(100.00 ± 10.00)％,(100.00 ± 9.00)％] and low fluoride group [(73.88 ± 3.36)％,(81.50 ± 14.90)％;(76.02 ± 8.65)％,(73.36 ± 7.43)％,P ＜ 0.05].The activities of SOD in serum in low and high fluoride groups after 6 month treatment [(37.94 ± 1.92),(35.54 ± 2.53) U/ml] were significantly lower than that of control group [(41.24 ± 0.66) U/ml,P ＜ 0.05],and the value in high fluoride group was lower than that in low fluoride group (P ＜ 0.05);serum MDA contents in high fluoride group after 3 and 6 month treatment [(8.29 ± 1.49),(11.63 ± 1.04) nmol/mg pr] were higher than those in low fluoride group [(6.39 ± 0.69),(7.50 ± 1.64) nmol/mg pr] and control group [(5.02 ± 0.71),(5.87 ± 1.03) nmol/mg pr,P ＜ 0.05].The correlation analysis results showed the levels of PPARγprotein in hippocampus and cortex of rats were negatively correlated with fluoride contents in brain tissues (3 month:r=-0.769,-0.793;6 month:r =-0.832,-0.870;P ＜ 0.05),positively correlated with SOD activities (3 month:r =0.550,0.826;6 month:r =0.822,0.896;P ＜ 0.05) and negatively correlated with MDA contents (3 month:r =-0.703,-0.609,6 month:r =-0.792,-0.657;P ＜ 0.05) in serum.Conclusions Declined expression of PPARγat protein and mRNA levels has been detected in brains of rats with chronic fluorosis,which might be related to the increase of oxidative stress.PPARγ may be involved in the occurrence of chronic fluorosis.

Objective To explore the effect of comprehensive nursing intervention in patients with acute myocardial infarction (AMI).Methods A total of 100 patients with acute myocardial infarction were randomly divided into two groups.The patients in the control group were given routine nursing and the patients in the experimental group were given comprehensive nursing intervention.Angina severity,quality of life,psychological status,incidence of adverse cardiac events and family care satisfaction before and after intervention were compared.Results Compared with the control group,the degree of physical activity limitation,angina pectoris stabilized status,angina pectoris attack status,treatment satisfaction and disease cognition score of the experimental group were significantly higher than that of the control group.After the intervention,the physiological function,physiological function,social function,emotional function,energy,mental health and general health status scores were significantly higher than the control group;Anxiety and depression scores were significantly lower than the control group;The overall incidence of adverse cardiac events was significantly lower (P ＜ 0.01).Conclusion The comprehensive nursing intervention has a significant effect in the first aid of acute myocardial infarction patients,which can improve the satisfaction of the family members.

Objective To explore the effect of comprehensive nursing intervention in patients with acute myocardial infarction (AMI).Methods A total of 100 patients with acute myocardial infarction were randomly divided into two groups.The patients in the control group were given routine nursing and the patients in the experimental group were given comprehensive nursing intervention.Angina severity,quality of life,psychological status,incidence of adverse cardiac events and family care satisfaction before and after intervention were compared.Results Compared with the control group,the degree of physical activity limitation,angina pectoris stabilized status,angina pectoris attack status,treatment satisfaction and disease cognition score of the experimental group were significantly higher than that of the control group.After the intervention,the physiological function,physiological function,social function,emotional function,energy,mental health and general health status scores were significantly higher than the control group;Anxiety and depression scores were significantly lower than the control group;The overall incidence of adverse cardiac events was significantly lower (P ＜ 0.01).Conclusion The comprehensive nursing intervention has a significant effect in the first aid of acute myocardial infarction patients,which can improve the satisfaction of the family members.