The impeller, as a key component of artificial heart pumps, experiences high shear stress due to its rapid rotation, which may lead to hemolysis. To enhance the hemolytic performance of artificial heart pumps and identify the optimal combination of blade parameters, an optimization design for existing pump blades is conducted. The number of blades, outlet angle, and blade thickness were selected as design variables, with the maximum shear stress within the pump serving as the optimization objective. A back propagation (BP) neural network prediction model was established using existing simulation data, and a grey wolf optimization algorithm was employed to optimize the blade parameters. The results indicated that the optimized blade parameters consisted of 7 impeller blades, an outlet angle of 25 °, and a blade thickness of 1.2 mm; this configuration achieved a maximum shear stress value of 377 Pa—representing a reduction of 16% compared to the original model. Simulation analysis revealed that in comparison to the original model, regions with high shear stress at locations such as the outer edge, root, and base significantly decreased following optimization efforts, thus leading to marked improvements in hemolytic performance. The coupling algorithm employed in this study has significantly reduced the workload associated with modeling and simulation, while also enhancing the performance of optimization objectives. Compared to traditional optimization algorithms, it demonstrates distinct advantages, thereby providing a novel approach for investigating parameter optimization issues related to centrifugal artificial heart pumps.
【Abstract】Objective To explore the differential diagnostic value of major fibrinolytic parameters in pleural fluid. Methods Tissue-type plasminogen activator( t-PA) and plasminogen activator inhibitor-1( PAI-1) in pleural fluid at the first thoracentesis were measured with ELISA and D-dimer was measured with immunoturbidimetry. Results Eighty-four patients with pleural effusion were enrolled, among which 40 with malignant effusion, 33 with infectious effusion and 11 with transudative effusion. t-PA level was higher in malignant and transudative pleural fluid than that in infectious pleural fluid[ ( 52. 49 ±31. 46) ng /mL and ( 58. 12 ±23. 14) ng /mL vs ( 37. 39 ±22. 44) ng /mL, P lt; 0. 05] , but was not statistically different between malignant pleural fluid and transudative ( P gt; 0. 05) . PAI-1 level was higher in malignant and infectious pleural fluid than that in transudative [ ( 164. 86 ±150. 22) ng/mL and ( 232. 42 ±175. 77) ng/mL vs ( 46. 38 ±16. 13) ng/mL, P lt; 0. 01] , but was not statistically different between malignant and infectious pleural fluid( P gt;0. 05) . D-dimer levels in the three types of pleural fluid were significantly different, which was ( 23. 66 ±25. 18) mg/L, ( 6. 36 ±10. 87) mg/L and ( 66. 90 ±42. 17) mg/L in malignant, transudative and infectious pleural fluid, respectively. As single-item detection for malignant pleural fluid, the cutoff of t-PA was gt; 38. 7 ng/mL( area under ROC curve was 64. 0 ) , with sensitivity of 60. 0% , specificity of 63. 6%, positive predictive value of 66. 7%, negative predictive value of 56. 8% and accuracy of 61. 6% .The cutoff of D-dimer was lt; 27. 0 mg/L( area under ROC curve was 85. 5) , with sensitivity of 84. 8% ,specificity of 72. 5% , positive predictive value of 85. 3% , negative predictive value of 71. 8% and accuracy of78.1%. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of combined examination( t-PA + D-dimer) were 92. 5% , 60. 6% , 74. 0% , 87. 0% , 78. 1% , respectively.Conclusions The t-PA, PAI-1 and D-dimer levels are significantly different in the three types of pleural fluid. The detection of fibrinolytic parameters in pleural fluid, especially the value of D-dimer,may be helpful in the differential diagnosis of pleural effusion.
According to the working principle of vertical ultrasonic vial washing machine, receiving respective force of small water droplets on the inside wall of vials and the minimum air velocity of blowing off water droplets can be obtained based on the analysis of water-droplet-related parameters. The inside wall model of 7 mL vial created by GAMBIT was divided into fine grids. Then the Realizable k-epsilon Two Equation Turbulence Model was adopted and the flow field of vial by FLUENT software was simulated when air was flushing inside the wall. In that case, the optimal position, inner diameter and the corresponding minimum air velocity of needle can be acquired to meet the needs of vial washing machine applied to 7 mL vial.
Low-intensity ultrasound stimulation of the retina has the ability to modulate neural activity in the primary visual cortex (V1), however, it is currently unclear how different intensities and durations of ultrasonic stimulation of the retina modulate neural activity in V1. In this paper, we recorded local field potential (LFP) signals in the V1 brain region of mice under different ultrasound intensities and different stimulation times. The amplitude of LFP corresponding to 1 s before ultrasound stimulation to 2 s after stimulation (–1–2 s) was analyzed, including the power and sample entropy of delta, theta, alpha beta, and low gamma frequency bands. The experimental results showed that, as the stimulation intensity increased, the peak value of the LFP in the visual cortex showed a linear upward trend; the power in the delta and theta frequency bands showed a linear upward trend, and the sample entropy showed a linear downward trend. With increases of stimulation duration, the peak value of the LFP in the visual cortex showed an upward trend, and the upward trend gradually weakened; the power in the delta frequency band showed an upward trend, the sample entropy showed a linear upward trend, and the sample entropy in the theta frequency band showed a downward trend. The results show that low-intensity ultrasonic stimulation of the retina has a significant modulatory effect on neural activity in the visual cortex. The study provides insights into the mechanisms by which ultrasonic stimulation regulates visual system function. Furthermore, it clarifies the patterns of parameter selection, facilitating the development of personalized multi-parameter modulation for the treatment of visual neural degeneration, retinal disorders and related research areas.
ObjectiveTo analyze the the characteristics of pulse oximetry (SpO2) curve changes in patients with obstructive sleep apnea (OSA), hypoxic parameters and to explore the difference and connection between obstructive apnea (OA) events and hypopnea (Hyp) events, evaluate the impact of different types of obstructive respiratory events on hypoxia, and provide a theoretical basis for exploration of hypoxic differences in each type of respiratory events and construction of prediction models for respiratory event types in the future. MethodsSixty patients with OSA diagnosed by polysomnography (PSG) were selected for retrospective analysis, and all respiratory events with oxygen drop in the recorded data overnight were divided into OA group (5972) according to the type of events and Hyp group (4110), recorded and scored events were exported from the PSG software as comma-separated variable (.csv) files, which were then imported and analyzed using the in-house built Matlab software. Propensity score matching was performed on the duration of respiratory events and whether they were accompanied by arousal in the two groups, and minimum oxygen saturation of events (e-minSpO2), the depth of desaturation (ΔSpO2), the duration of desaturation and resaturation (DSpO2), the duration of desaturation (d.DSpO2), duration of resaturation (r.DSpO2), duration of SpO2<90% (T90), duration of SpO2<90% during desaturation (d.T90), duration of SpO2<90% during resaturation (r.T90), area under the curve of SpO2<90% (ST90), area under the curve of SpO2<90% during desaturation (d.ST90), area under the curve of SpO2<90% during resaturation (r.ST90), oxygen desaturation rate (ODR) and oxygen resaturation rate (ORR), a total of 13 hypoxic parameters differences. ResultsVarious hypoxic parameters showed that more severe SpO2 desaturation in severe OSA patients, compared with mild and moderate OSA patients (P<0.05); There were statistically significant differences in the respiratory events duration and whether accompanied by arousal between the Hyp group and OA group (P<0.05), and the respiratory events duration and whether accompanied by arousal were significantly correlated with most hypoxic parameters; After accounting for respiratory events duration and whether accompanied by arousal by propensity score matching, compared with the Hyp group, e-minSpO2 was significantly lower in the OA group, ΔSpO2, d.DSpO2, r.DSpO2, ODR, ORR, T90, d.T90, r.T90, ST90, d.ST90, r.ST90 were significantly increased (P<0.05). ConclusionsDue to pathophysiological differences, all hypoxic parameters suggest that OA events will result in a more severe desaturation than Hyp events. Clinical assessment of OSA severity should not equate OA with Hyp events, which may cause more damage to the organism, establishing a basis for applying nocturnal SpO2 to automatically identify the type of respiratory event.
Objective To investigate the effect of the sagittal alignment of the spine and pelvis after surgical posterior intervertebral fusion combined with pedicle screw fixation for low-grade isthmic lumbar spondylolisthesis, and to assess the effectiveness. Methods Between October 2009 and October 2011, 30 patients with low-grade isthmic spondylolisthesis underwent surgical posterior intervertebral fusion combined with pedicle screw fixation, and the clinical data were retrospectively reviewed. There were 14 males and 16 females with an average age of 56.7 years (range, 48-67 years). The pre- and post-operative radiographic parameters, such as percentage of slipping (PS), intervertebral space height, angle of slip (AS), thoracic kyphosis (TK), thoracolumbar junction angle (TLJ), sagittal vertical axis (SVA), lumbar lordosis (LL), spino-sacral angle (SSA), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI) were measured. The functional evaluation was made using the Oswestry Disability Index (ODI). Pearson correlation were used to investigate the association between all parameters and ODI score. Results PS, intervertebral space height, AS, and ODI were improved significantly compared with properative ones (P lt; 0.05). Significant differences were found in the other parameters between pre- and post-operation (P lt; 0.05) except TLJ and TK. The alteration of SVA showed significant correlation with the changes of PS, PI, PT, LL, SS, AS, SSA, and ODI. The alteration of SSA showed significant correlation with the changes of PS, PI, LL, SS, AS, PT, and ODI. Conclusion Surgical posterior intervertebral fusion combined with pedicle screw fixation for low-grade isthmic spondylolisthesis can effectively improve and maintain the spinal sagittal parameters. SVA and SSA are adequate to evaluate pre-and post-operative balance. The good clinical outcome is closely related with the improved of SVA and SSA.
Objective To establish amedical reference for adult pulmonary function parameters and a normal FEV1 /FVC% pred in population of Shanghai. Methods Subjects who underwent routine physical examination were initially screened and those who met enrollment criteria with age over 18 years old were required to underwent pulmonary function tests in Zhongshan Hospital from June 2009 to February 2010. After screening of 450 subjects, a total of 240 subjects with normal pulmonary function and 120 subjects with mild small airway abnormalities were enrolled in this study according to the prediction equations established in1988. All subjects were assigned into 6 groups according to their age with30 males amd 30 females in each group. Pulmonary function parameters including VC, FVC, FEV1 , FEV1 /FVC, PEF, FEF25% , FEF50% , FEF75% , RV, FRC, TLC, RV /TLC, DLCO, and KCO were collected for analysis. New prediction equations for the above 14 parameters were established by parameters of anthropometry. The medical reference ranges of 14 parameters were calculated according to the newprediction equations. The normal FEV1 /FVC%pred was also calculated. Results New prediction equations for normal adult pulmonary function parameters in Shanghai were established. DLCO =5.206 +4. 314 ×gender ( “male”= 1, “female”=0) - 0. 144 ×age( y) +0. 098 × height( cm) +0. 082 ×weight( kg) , KCO =9. 346 - 0. 026 ×age( y) - 0. 031 ×height( cm) +0. 025 ×weight( kg) .The LLN( P5) of VC, FVC, FEV1 , FEV1 /FVC, the LLN( P2. 5 ) and the upper limit of normal value ( P97. 5) of FRC, TLC, RV, RV/TLC were calculated. The LLN( P5) of FEV1 /FVC = 101. 924 - 0. 144 × age ( y) - 0. 118 ×high( cm) . The lower normal limit of FEV1 /FVC% pred was 92% . Conclusions This is the first time to have the medical reference of FEV1 /FVC% pred in China, and new prediction equations for DLCO in Shanghai. The LLN of FEV1 /FVC or FEV1 /FVC% pred lt;92% can be used as diagnostic criteria for obstructive ventilation disorder. Instead of using FEV1% pred lt; 80% , FEV1 lt; LLN can be used as diagnostic criteria for mild ventilation disorder.
In order to study the variation of complex impedance and characteristic parameters on human normal and tumor lung tissue during the extracorporeal time, we established a real part-imaginary part chart of complex impedance on lung tissue which provided the basic theory and the reference data for research on elementary medicine and clinical diagnosis of lung cancer and meanwhile provided prior information for electrical impedance tomography (EIT) research. In the experiment carried out in our laboratory, when operation was finished, we kept the lung cancer tissue and normal tissue neatly separated into the cylindrical testing cavities and kept the temperature and humidity at expected values. Then the measurements of complex impedance property are performed at frequency from 1 000 Hz to 30 MHz using 4294A impedance analyzer of Aglient Company. With time changing, the results showed that there was a significant change occurring on the complex impedance of human normal and tumor lung tissue. However, the impedance of normal lung tissue is greater than that of tumor lung tissue. We consider that this change should be related to the change in extracellular fluid, intracellular fluid and cell membrane.
Objective To explore the relevance of serum homocysteine (Hcy) level to erythrocyte and platelet parameters in patients with unstable angina pectoris (UAP). Methods Sixty patients with UAP were collected in Tongling Municipal Hospital from August 1st, 2012 to December 31st, 2015. Serum Hcy was measured by enzymatic cycling method. Erythrocyte parameters, such as red blood cell count (RBC), hemoglobin, mean corpuscular volume (MCV), coefficient of variation of red blood cell volume distribution width (RDW-CV), and platelet parameters, such as platelet count (PLT), platelet distribution width (PDW), mean platelet volume (MPV), platelet large cell ratio (P-LCR), were measured with blood cell counter. All patients were classified into UAP with hyperhomocystinemia (HHcy) group and UAP with normal Hcy group according to the level of Hcy. The data in two groups were analyzed and the relevance of serum Hcy level to erythrocyte and platelet parameters was evaluated. Results The differences in the levels of RBC, hemoglobin, MCV, PLT, PDW, MPV, P-LCR between the two groups were not statistically significant (P>0.05); while the levels of RDW-CV and the proportion of RDW-CV above the upper reference limit of patients in the UAP with HHcy group (13.81%±1.13%, 39.4%) were higher than those in the UAP with normal Hcy group (13.06%±0.97%, 4.8%), and the differences between the two groups were statistically significant (P<0.05). Correlation analysis showed that serum Hcy level of patients with UAP was significantly correlated with RDW-CV (r=0.380, P<0.01) and was not significantly correlated with other erythrocyte and platelet parameters (P>0.05). Conclusion The high level of Hcy affects red blood cell volume heterogeneity in patients with UAP, which may be one of the mechanisms of HHcy participating in the occurrence and development of UAP.
Objective To systematically review the value of the perfusion paramenters of Ktrans and Kep of dynamic contrast enhanced MRI(DCE-MRI) in distinguishing different histological grades of rectal cancer. Methods Databases such as PubMed, EMbase, Web of Science, The Cochrane Library (Issue 1, 2017), CBM, CNKI, WanFang Data and VIP were searched from 1990 to Feb 6th, 2017 to collect the studies according to the criteria. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies and then meta-analysis was performed by using STATA 12.0 software. Results A total of 11 studies involving 618 patients were included. The results of meta-analysis showed that there was significant difference of Ktrans between poorly differentiated grade and moderately-well differentiated grade (SMD=1.123, 95% CI 0.334 to 1.911,P=0.005), but there was no significant difference of Kep between these two groups (SMD=0.233, 95% CI –0.173 to 0.639,P=0.260). Conclusion Current evidence shows that Ktrans can be used to distinguish different histological grades of rectal cancer. The clinical application value of Kep still needs large sample original studies to further verify.