Objective To investigate the impact of variations in volute cross-sectional area on the flow characteristics and hemolytic performance of centrifugal blood pumps by designing six volute structures.Methods Computational fluid dynamics and the Lagrangian method were used to analyze flow characteristics and predict hemolysis in blood pumps with different volute designs.Results The annular volute pump showed the poorest hydraulic performance,while the hydraulic performance of the S-shaped volute was the best,which was improved by 35.29％compared to that of the annular volute.Some volutes experienced stagnation zones at the helical inlet(0°-90°)and significant backflow at the outlet(270°-360°).The downward concave-shaped volute had the highest hemolysis index(HI),i.e.,9.59×10-4.Meanwhile,the HI of the annular volute was the lowest,which was 71.85％less than the concave-shaped volute.Conclusions Reducing the gradient of the area variation at the helical inlet and outlet can prevent flow stagnation and backflow.A higher HI arises due to the prolonged exposure of red blood cells to high shear stress.This study provides a theoretical basis for designing and optimizing volute structures of centrifugal blood pumps.

Tesla blood pumps demonstrate a reduced propensity for hemolysis and thrombosis compared with vane blood pumps. Considering the restricted driving force within the secondary flow channel of vane blood pumps, along with the low hydraulic efficiency of conventional Tesla blood pumps and their internal flow characteristics that significantly contribute to hemolysis and thrombosis, this study introduces a set of vanes atop the rotor of the Tesla blood pump. This forms a dual-fluid domain rotor, and an axial dual-outlet volute shell structure is adopted to realize the separation of the fluid domains. Through numerical simulations of the new structure, a comparative analysis was conducted in this study on the internal flow characteristics of double-outlet and single-outlet volute shells, and symmetric and asymmetric cross-sections of the same rotor. The results indicate that the flow field distribution is more uniform under the double-outlet volute shell structure, and overall energy dissipation is decreased. After implementing the double-outlet design, in the asymmetric cross-section, compared with the symmetric cross-section, the fluid velocity gradient and turbulent kinetic energy at the tongue of the septum are reduced, and the fluid velocity gradient at the convergence of the diffuser tube outlets are also decreased. The maximum scalar stress is lower, and the decline in head and efficiency is mitigated. Moreover, compared with the single-outlet volute shell, the hemolysis index in the asymmetric cross-section is reduced. In summary, this paper proposes a novel dual-outlet centrifugal disk blood pumps, which can provide a reference for the structural design and performance optimization of magnetically levitated centrifugal blood pumps.
Heart-Assist Devices ; Humans ; Equipment Design ; Hemolysis ; Computer Simulation

Objective To study the effects of different clearance conditions(equal upper and lower axial clearance,change of upper/lower axial clearance,axial displacement of blades)on efficiency and hemolysis performance of blood pump.Methods The blood pumps under three kinds of clearance conditions were numerically simulated by computational fluid dynamics.Results For efficiency,when the upper and lower axial clearance was equal,the lower axial clearance was unchanged and the upper axial clearance was reduced,the efficiency of blood pump could be improved by 0.85%,1.71%and 2.90%,respectively.While the upper shaft clearance remained unchanged,the lower shaft clearance was decreased by 1.18%.For hemolysis,the increase of the clearance could reduce the hemolysis index(HI)under the first two clearance conditions,while the axial migration of the blade wheel would increase the HI.When the upper axial clearance was unchanged and the lower axial clearance was 0.3 mm,the HI was the largest,which was 8.65×10-4.When the upper and lower axial clearance was 0.7 mm,the HI was the smallest,which was 4.51×10-4.Conclusions Improving blood pump clearance is helpful to optimize the performance of blood pump.This study can provide some references for the design and optimization of interstitial structure of blood pump.

Objective To study the effects of different clearance conditions(equal upper and lower axial clearance,change of upper/lower axial clearance,axial displacement of blades)on efficiency and hemolysis performance of blood pump.Methods The blood pumps under three kinds of clearance conditions were numerically simulated by computational fluid dynamics.Results For efficiency,when the upper and lower axial clearance was equal,the lower axial clearance was unchanged and the upper axial clearance was reduced,the efficiency of blood pump could be improved by 0.85%,1.71%and 2.90%,respectively.While the upper shaft clearance remained unchanged,the lower shaft clearance was decreased by 1.18%.For hemolysis,the increase of the clearance could reduce the hemolysis index(HI)under the first two clearance conditions,while the axial migration of the blade wheel would increase the HI.When the upper axial clearance was unchanged and the lower axial clearance was 0.3 mm,the HI was the largest,which was 8.65×10-4.When the upper and lower axial clearance was 0.7 mm,the HI was the smallest,which was 4.51×10-4.Conclusions Improving blood pump clearance is helpful to optimize the performance of blood pump.This study can provide some references for the design and optimization of interstitial structure of blood pump.

Objective To investigate the impact of variations in volute cross-sectional area on the flow characteristics and hemolytic performance of centrifugal blood pumps by designing six volute structures.Methods Computational fluid dynamics and the Lagrangian method were used to analyze flow characteristics and predict hemolysis in blood pumps with different volute designs.Results The annular volute pump showed the poorest hydraulic performance,while the hydraulic performance of the S-shaped volute was the best,which was improved by 35.29％compared to that of the annular volute.Some volutes experienced stagnation zones at the helical inlet(0°-90°)and significant backflow at the outlet(270°-360°).The downward concave-shaped volute had the highest hemolysis index(HI),i.e.,9.59×10-4.Meanwhile,the HI of the annular volute was the lowest,which was 71.85％less than the concave-shaped volute.Conclusions Reducing the gradient of the area variation at the helical inlet and outlet can prevent flow stagnation and backflow.A higher HI arises due to the prolonged exposure of red blood cells to high shear stress.This study provides a theoretical basis for designing and optimizing volute structures of centrifugal blood pumps.

Objective To observe the effect of 3R therapy on quality of life and subjective well-being in older patients with mild cognitive impairment (MCI). Methods 158 patients with MCI were collected from 8 communities in Ningbo city with Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV as the diagnostic criteria, and assessed by Montreal Cognitive Assessment (MoCA). The experimental group (n=79) was intervened by 3R (Reminiscence, Reality Orientation, Remotivation) for 12 weeks, and the control group (n=79) received no intervention. Their quality of life was assessed with WHO Quality of Life-BREF (WHOQOL-BREF) and the subjective well-being was assessed with Philadelphia Geriatric Center Morale Scale (PGC). Results Their quality of life and subjective well-being improved after intervention in the experimental group (P<0.05), and were better in the experimental group than in the control group (P<0.05). Conclusion 3R therapy could effectively improve the quality of life and subjective well-being in patients with MCI.

Objective To evaluate the relationship between lifestyle and development of Alzheimer's disease(AD).Methods Two hundred and thirty-eight AD patients(102 males and 136 females) and 476 healthy controls(204 males and 272 females) were recruited from Ningbo communities into this 1 ∶ 2 matched case-control study.Mini-Mental State Examination(MMSE) and Clinical Dementia Rating(CDR) were required to fill in.Chi-square test and conditional logistic regression were used for data analysis.We adopted Epidata 3.1 to establish the database and did statistical analysis by SPSS15.0.The count data were analysis by Chi-square test,meanwhile multiple factors analysis by conditional Logistic regression analysis.Results Through single factor analysis we found thatcigarette ≥20/day(F=8.687,P=0.003),children visiting(F=22.721,P＜0.05),friendship(F=16.784,P＜0.05),family gathering(≥1 times/week)(F=8.198,P=0.004),working after retirement(F=33.099,P＜0.05),travel(F=16.784,P＜0.05),social activities(F=24.919,P＜0.05),physical exercises(F=24.404,P＜0.05),eating pickles or pickled products(F=6.662,P=0.01),saturated fatty acid intake(F=23.069,P＜0.05),daily consumption of fruits and vegetables(F=8.401,P=0.004),chess(F=17.365,P＜0.05),reading(≥30 min/d)(F=36.390,P＜0.05),using computer(F=8.688,P=0.003) were related AD,the difference was statistically significant(P＜0.05).In multiple factors analysis,social activities,chess games or joke,travelling,working after retirement,reading,physical exercises,friendship,family gathering,saturated fatty acid intake and daily consumption of fruits and vegetables were risk factors of AD(odds ratio(OR) values were 0.571(0.342-0.753),0.623(0.343-0.889),0.686(0.461-0.942),0.534(0.326-0.714),0.276(0.175-0.438),0.538(0.336-0.738),0.585(0.385-0.765),0.466(0.316-0.745),0.527 (0.368-0.787) and 0.482(0.316-0.665),respectively; constant terms:OR=0.526).Conclusion A positive and leisure lifestyle and health reasonable diet could effectively reduce the risk of AD.

Objective To explore clinical progress about the deep vein thrombosis after hip replacement at home and abroad,and discuss the preventive effect of nursing intervention.Methods The documents about the deep vein thrombosis after hip replacement were retrieved from PUBMED,China National Network Knowledge Infrastructure (CNKI),Chinese Scientific Journal Database (VIP),Chinese Bio Medical Literature Database (CBM) and Wan fang Database.And the retrieving duration was from 1st Jan.2001 to 1st Sept.2013.The research progress about prevention of deep vein thrombosis after hip replacement was analyzed through the analysis of the same and the difference of comparative literatures at home and abroad.Results There were totally 228 Chinese documents and 5 English documents of the deep vein thrombosis after hip replacement,and the number of document showed an increasing trend year by year.In the past five years,the clinical progress about the deep vein thrombosis after hip replacement was obvious,the research methods used was accurate,the involving intervention measures was continuously improved,literature quality was increased.Conclusions The quality of the documents published in domestic Chinese journals needs to be improved,and we should improve the quality of research design,research new methods of intervention,formulate the optimal nursing measures in order to achieve optimal care.

Objective To investigate the factors of lifestyle associated with the mild cognitive impairment (MCI). Methods A 1∶ 2 matched case-control study investigated 120 patients of MCI and 240 healthy controls with lifestyle factors associated with MCI. Results Multiple factors analysis confirmed that, participate in social activities (OR=0.562, 95%CI: 0.359~0.723), playing chess or joke (OR=0.603,95%CI: 0.323~0.884), travelling (OR=0.683, 95%CI: 0.467~0.912), continue to work after retirement (OR=0.531, 95%CI: 0. .326~0.724),reading (OR=0.272, 95%CI: 0.174~0.428), using computer (OR=0.536, 95%CI: 0.427~0.869), regular physical exercise (OR=0.437, 95% CI: 0.316~0.732), friendship (OR=0.583, 95%CI: 0.385~0.765), meeting children (OR=0.464, 95%CI: 0.316~0.745), intaking unsaturated fatty acids (OR=0.524, 95%CI: 0.368~0.787), often eating fish and seafood (OR=0.224, 95%CI: 0.171~0.383), daily consumption of fruits and vegetables (OR=0.485, 95%CI: 0.316~0.665) were protective factors for MCI. Conclusion A positive, leisure lifestyle, health reasonable diet and avoiding risk factors could effectively reduce the risk of MCI.

Objective To reassess the treatment of Bosniak category Ⅱ-Ⅲ renal cyst.Methods Sixty-eight cases of Bosniak category Ⅱ-Ⅲ renal cyst were operated from 2005 to 2008 in our institute.The average patient age was 40 years with the average renal cyst diameter of 5.1 cm.There were 37 left lesions and 31 right lesions with 31 cases of category Ⅱ (including 13 cases of category Ⅱ F) and 37 cases of category Ⅲ.Renal unroofing were performed in 49 cases with 9 cases found malignant and followed by radical nephrectomy,19 cases were diagnosed as malignancy preoperatively and nephron sparing surgery or radical nephrectomy were performed in these cases.Results Malignant lesions were found in 21 cases and benign lesions were found in 47 cases.The malignant rate was 9.7％ in category Ⅱ (15.4％ in category Ⅱ F),48.6％ in category Ⅲ.Nine cases were diagnosed benign preoperatively but confirmed malignancy after operation; 7 cases were diagnosed malignancy preoperatively but confirmed benign after operation.Forty-two cases were followed up for 8-65 months with 15 cases of malignancy and 27 cases of benign lesions.The recurrence of renal cyst occurred in 6 cases of benign lesions and recurrence and metastasis occurred in 3 cases of malignancy in 1-5 years.Conclusions It is difficult to draw a therapeutic principle for Bosniak category Ⅱ-Ⅲ renal cyst because of the uncertainty of the lesion.Partial nephrectomy or renal cystectomy is a good choice in the treatment of Bosniak category Ⅱ-Ⅲ renal cysts.