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.
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.
For the detection and identification of abnormal nodular tissues on the body surface, a microwave sensor structure loaded with a spiral resonator is proposed in this paper, a sensor simulation model is established using HFSS software, the structural parameters are optimized, and the actual sensor is fabricated. The S21 parameters of the tissue were obtained when nodules appeared by simulation, and the characteristic relationship between the difference of S21 parameters with position was analyzed and tested experimentally. The results showed that when nodules were present in normal tissues, the curve of S21 parameter difference with position change had obvious inverted bimodal characteristics, and the extreme value of S21 parameter difference appeared when the sensor was directly above the nodules, which was easy to identify the position of nodules. It provides an objective detection tool for the identification of abnormal nodular tissues on the body surface.
There is a shared problem in current optical imaging technologies of how to obtain the optical parameters of biological tissues with complex profiles. In this work, an imaging system for obtaining the optical parameters of biological tissues with complex profile was presented. Firstly, Fourier transformation profilometry was used for obtaining the profile information of biological tissues, and then the difference of incident light intensity at different positions on biological tissue surface was corrected with the laws of illumination, and lastly the optical parameters of biological tissues were achieved with the spatial frequency domain imaging technique. Experimental results indicated the proposed imaging system could obtain the profile information and the optical parameters of biological tissues accurately and quickly. For the slab phantoms with height variation less than 30 mm and angle variation less than 40º, the maximum relative errors of the profile uncorrected optical parameters were 46.27% and 72.18%, while the maximum relative errors of the profile corrected optical parameters were 6.89% and 10.26%. Imaging experiments of a face-like phantom and a human’s prefrontal lobe were performed respectively, which demonstrated the proposed imaging system possesses clinical application value for the achievement of the optical parameters of biological tissues with complex profiles. Besides, the proposed profile corrected method can be used to combine with the current optical imaging technologies to reduce the influence of the profile information of biological tissues on imaging quality.
Objective To investigate the changes of low back pain (LBP) and spinal sagittal parameters in patients with unilateral Crowe type Ⅳ developmental dysplasia of the hip (DDH) after total hip arthroplasty (THA). Methods The clinical data of 30 patients who met the selection criteria between October 2018 and March 2020 were retrospectively analyzed. Patients were divided into LBP group (16 cases) and control group (14 cases) according to whether there was LBP before operation. There was no significant difference between the two groups of patients in gender, age, body mass index, affected sides, preoperative Harris score (P>0.05). Full-length lateral X-ray films of the spine were taken within 1 week before operation and at 1 year after operation, and the following imaging indicators were measured: sacral slope (SS), lumbar lordosis (LL ), spinal tilt (ST), spine-sacral angle (SSA), sagittal vertebral axis (SVA). The visual analogue scale (VAS) score, lumbar Oswestry disability index (ODI), the Harris score of the hip joint before operation and at 1 year after operation, and the occurrence of postoperative complications were collected and analysed. Results In the LBP group, LBP was relieved to varying degrees at 1 year after operation, of which 13 patients (81.3%) had complete LBP remission; VAS score decreased from 4.9±2.3 preoperatively to 0.3±0.8, ODI decreased from 33.5±22.6 preoperatively to 1.3±2.9, the differences were all significant (t=7.372, P=0.000; t=5.499, P=0.000). There was no new chronic LBP in the control group during follow-up. The Harris scores of the two groups significantly improved when compared with those before operation (P<0.05); there was no significant difference between the two groups at 1 year after operation (t=0.421, P=0.677). There was no significant difference in imaging indexes between the two groups before operation and the difference between pre- and post-operation (P>0.05). At 1 year after operation, ST and SVA in the LBP group, SSA in the control group, and SS in the two groups significantly improved when compared with those before operation (P<0.05); there was no significant difference in the other indexes between the two groups before and after operation (P>0.05). Conclusion Unilateral Crowe type Ⅳ DDH patients with LBP before operation were all relieved of LBP after THA. The relief of LBP may be related to the improvement of spinal balance, but not to lumbar lordosis and its changes.
Hemodynamics plays a vital role in the development and progression of cardiovascular diseases, and is closely associated with changes in morphology and function. Reliable detection of hemodynamic changes is essential to improve treatment strategies and enhance patient prognosis. The combination of computational fluid dynamics with cardiovascular imaging technology has extended the accessibility of hemodynamics. This review provides a comprehensive summary of recent developments in the application of computational fluid dynamics for cardiovascular hemodynamic assessment and a succinct discussion for potential future development.
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.
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.
ObjectiveTo explore the application value of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) quantitative parameters and apparent diffusion coefficient (ADC) value in evaluating the differentiation degrees and T stages of rectal cancer.MethodsThe patients with rectal cancer from November 2017 to November 2019 in the Sichuan Provincial People’s Hospital were collected. The volume transfer constant (Ktrans), flux rate constant (Kep), and extravascular extracellular volume fraction (Ve), and ADC values of the tumors were measured and compared in the patients with the different differentiation degrees and T stages. The receiver operating characteristic (ROC) curve analysis was performed.ResultsAll of 53 eligible patients were included, including 13 cases of high differentiation, 30 cases of medium differentiation, and 10 cases of low differentiation; 5 cases of T1 stage, 8 cases of T2 stage, 24 cases of T3 stage, and 16 cases of T4 stage. ① There were statistical differences in the Ktrans and ADC values among the different differentiation degrees of rectal cancer (P=0.004, P<0.001), and no statistical differences in the Kep and Ve values (P>0.050) among them. The Ktrans value was increased with decreased differentiation degree (P<0.050), the ADC value was decreased with decreased differentiation degrees (P<0.050). ② There were statistical differences in the Ktrans and ADC values among the different T stages of rectal cancer (P=0.002; P=0.007), and no statistical differences in the Kep and Ve values (P>0.050) among them. The Ktrans and ADC values were statistically different between the T2 and T3 stages of rectal cancer (P=0.009, P=0.013). ③ The Ktrans and ADC values could distinguish the high and medium differentiation degrees of rectal cancer, its area under ROC curve (AUC) values were 0.677 and 0.763, respectively, and the corresponding best thresholds were 0.180/min and 1.179 mm2/s; The Ktrans and ADC values could distinguish the medium and low differentiation degrees of rectal cancer, its AUC values were 0.693 and 0.967, and the corresponding best thresholds were 0.281/min and 0.906 mm2/s; The Ktrans and ADC values could distinguish the T2 and T3 stages of rectal cancer, its AUC values were 0.862 and 0.742, and the corresponding best thresholds were 0.204/min and 1.579 mm2/s.ConclusionDCE-MRI quantitative parameters and ADC value before surgery to determine the different differentiation degrees and T stages of rectal cancer have certain reference value, the best Ktrans and ADC thresholds to distinguish different differentiation degrees and T2 to T3 stages can be obtained through statistical analysis.
ObjectiveTo find out the diagnostic power and correlation between platelet-related parameters and inflammatory indicators in acute pancreatitis patients with different severity.MethodsA total of 88 patients with acute pancreatitis diagnosed in West China Hospital of Sichuan University from January 2019 to August 2019 were enrolled in the retrospective study, including 58 mild acute pancreatitis patients and 30 severe acute pancreatitis patients. The patients’ platelet-related parameters and inflammatory indicators were collected. The platelet parameters and inflammatory indicators in different severity acute pancreatitis groups were compared and the diagnostic power and correlation were analyzed.ResultsThe platelet count and plateletcrit of the severe group were lower than those of the mild group, the difference was statistically significant (Z=–5.502, –3.673; P<0.001). The immature platelet fraction, platelet distribution width, mean platelet volume and platelet-large cell ratio levels of the severe group were higher than those of the mild group (Z=–4.217, –2.998, –3.754, –3.816; P<0.05). Platelet-related parameters platelet count, immature platelet fraction, platelet distribution width, mean platelet volume, platelet-large cell ratio, plateletcrit and inflammatory indicators procalcitonin, interleukin-6 showed good diagnostic power with areas under under receiver operating characteristic curves greater than 0.75 in differentiating the severity of acute pancreatitis. Correlation analysis showed that immature platelet fraction was positively correlated with procalcitonin and interleukin-6 levels in patients with acute pancreatitis (rs=0.457, 0.385; P<0.05).ConclusionsImmature platelet fraction is correlated with the severity of acute pancreatitis, and positively correlated with the levels of inflammatory indicators procalcitonin and interleukin-6.