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find Keyword "phase" 40 results
  • Constitution of a Real-time Monitoring System of Cerebral Hemorrhage with Magnetic Induction

    The real-time monitoring of cerebral hemorrhage can reduce its disability and fatality rates greatly. On the basis of magnetic induction phase shift, we in this study used filter and amplifier hardware module, NI-PXI data-acquisition system and LabVIEW software to set up an experiment system. We used Band-pass sample method and correlation phase demodulation algorithm in the system. In order to test and evaluate the performance of the system, we carried out saline simulation experiments of brain hemorrhage. We also carried out rabbit cerebral hemorrhage experiments. The results of both saline simulation and animal experiments suggested that our monitoring system had a high phase detection precision, and it needed only about 0.030 4s to finish a single phase shift measurement, and the change of phase shift was directly proportional to the volume of saline or blood. The experimental results were consistent with theory. As a result, this system has the ability of real-time monitoring the progression of cerebral hemorrhage precisely, with many distinguished features, such as low cost, high phase detection precision, high sensitivity of response so that it has showed a good application prospect.

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  • Recognition of Walking Stance Phase and Swing Phase Based on Moving Window

    Wearing transfemoral prosthesis is the only way to complete daily physical activity for amputees. Motion pattern recognition is important for the control of prosthesis, especially in the recognizing swing phase and stance phase. In this paper, it is reported that surface electromyography (sEMG) signal is used in swing and stance phase recognition. sEMG signal of related muscles was sampled by Infiniti of a Canadian company. The sEMG signal was then filtered by weighted filtering window and analyzed by height permitted window. The starting time of stance phase and swing phase is determined through analyzing special muscles. The sEMG signal of rectus femoris was used in stance phase recognition and sEMG signal of tibialis anterior is used in swing phase recognition. In a certain tolerating range, the double windows theory, including weighted filtering window and height permitted window, can reach a high accuracy rate. Through experiments, the real walking consciousness of the people was reflected by sEMG signal of related muscles. Using related muscles to recognize swing and stance phase is reachable. The theory used in this paper is useful for analyzing sEMG signal and actual prosthesis control.

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  • Analysis of Influencing Factors of Pregnant Women with Prolonged Latency Phase

    Objective To analyze the main reason of prolonged latency phase and the impact of prolonged latency phase on the delivery style. Methods The pregnant women with prolonged latency phase (n=92) and normal pregnant women (n=100) were retrospectively analyzed in the maternity department of the second affiliated hospital of Kunming medical college in 2007. Results There was no significant difference in the pelvis and fetal-pelvis in the two groups. The number of the pregnant women with fetal body weight (gt;4 000 g) in the prolonged latency phase group was obviously larger than that in the normal pregnant women group, with the significant difference. As to the situation of fetal position, there were more occipitoanterior positions and fewer occipitoposterior as well as occipitotransterse positions in the prolonged latency phase group (Plt;0.01). In the prolonged latency phase group, the pregnant women with normal delivery were fewer and the uterine-incision deliveries were more than those in the normal group, with the significant difference. Conclusion The prolonged latency phase prognosticates the incidence of dystocia. We should decide if the pregnant women have the tendency of prolonged latency phase before delivery and deal with it in time so as to prevent the occurrence of dystocia.

    Release date:2016-09-07 11:23 Export PDF Favorites Scan
  • Lightweight end-to-end model-based korotkoff sounds phase identification and blood pressure measurement

    Objective To propose a lightweight end-to-end neural network model for automated Korotkoff sound phase recognition and subsequent blood pressure (BP) measurement, aiming to improve measurement accuracy and population adaptability. Methods We developed a streamlined architecture integrating depthwise separable convolution (DSConv), multi-head attention (MHA), and bidirectional gated recurrent unit (BiGRU). The model directly processes Korotkoff sound time-series signals to identify auscultatory phases. Systolic BP (SBP) and diastolic BP (DBP) were determined using Phase Ⅰ and PhaseⅤdetections, respectively. Given the clinical relevance of phase Ⅳ for specific populations (e.g., children and pregnant women, denoted as DBPIV), BP values from this phase were also recorded. Results The study enrolled 106 volunteers with 70 males, 36 females at mean age of (40.0±12.0) years. The model achieved 94.25% phase recognition accuracy. Measurement errors were (0.1±2.5) mm Hg (SBP), (0.9±3.4) mm Hg (DBPIV), and (0.8±2.6) mm Hg (DBP). Conclusion Our method enables precise phase recognition and BP measurement, demonstrating potential for developing population-adaptive blood pressure monitoring systems.

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  • Isolation and Purification of α-Glycerophosphate Oxidase in a Polyethylene Glycol/(NH4)2SO4 Aqueous Two-phase System

    Alpha-glycerophosphate oxidase (α-GPO) from Enterococcus casseliflavus was successfully isolated and purified by using polyethylene glycol (PEG)/(NH4)2SO4 aqueous two-phase system (ATPS). The results showed that the chosen PEG/(NH4)2SO4 ATPS could be affected by PEG molecular weight, pH, concentration of PEG and (NH4)2SO4, and inorganic salt as well as additional amount of crude enzyme. After evaluating these influencing factors, the final optimum purification strategy was formed by 16.5% (m/m) PEG2000, 13.2% (m/m) (NH4)2SO4, pH 7.5 and 30% (m/m) additive crude enzyme, respectively. The NaCl was a negative influencing factor which would lead to lower purification fold and activity recovery. These conditions eventually resulted in the activity recovery of 89% (m/m), distribution coefficient of 1.2 and purification fold of 7.0.

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  • Reinforce the awareness of prevention of critical cerebral infarction by categories and phases

    Massive and severe cerebral infarction can lead to a high mortality and disability rate, and it is the bottleneck of preventing and treating cerebrovascular disease. Once the malignant brain edema of massive cerebral infarction or the critical status of severe cerebral infarction occurs, the treatment effect is very poor. Therefore, we should not only focus on the treatment of critical cerebral infarction, but also prevent its occurrence. It is clinically important to prevent the occurrence of this critical condition in advance and to prevent the occurrence of massive cerebral infarction and severe cerebral infarction. This article points out that some patients with massive or severe cerebral infarction can be prevented from becoming critically ill. The definition, key risk factors and corresponding prevention and treatment strategies of critical cerebral infarction have also been proposed. Critical cerebral infarction can be divided into two categories with or without malignant brain edema, and the risk factors and prediction and prevention strategies by categories andphases can be studied separately.

    Release date:2021-07-22 06:28 Export PDF Favorites Scan
  • Effect of percutaneous kyphoplasty with different phases bone cement for treatment of osteoporotic vertebral compression fractures

    ObjectiveTo compare the effect of percutaneous kyphoplasty (PKP) with different phases bone cement for treatment of osteoporotic vertebral compression fracture (OVCF).MethodsThe clinical data of 219 OVCF patients who treated with PKP and met the selection criteria between June 2016 and May 2018 were retrospectively analyzed. According to the different time of intraoperative injection of bone cement, they were divided into observation group [116 cases, intraoperative injection of polymethyl methacrylate (PMMA) bone cement in low-viscosity wet-sand phase)] and control group (103 cases, intraoperative injection of PMMA bone cement in low-viscosity wire-drawing phase). There was no significance in general date of gender, age, disease duration, body mass index, bone mineral density T value, fracture vertebral body, preoperative fracture severity of the responsible vertebral body, anterior height ratio of the responsible vertebral body, preoperative pain visual analogue scale (VAS) score, and Oswestry disability index (ODI) between the two groups (P>0.05). The VAS score and ODI score were used to evaluate the improvement of patients’ symptoms at immediate, 2 days, 3 months after operation and at last follow-up. At 1 day, 3 months after operation, and at last follow-up, X-ray film and CT of spine were reexamined to observe the distribution of bone cement in the vertebral body, bone cement leakage, and other complications. During the follow-up, the refracture rate of the responsible vertebral body and the fracture rate of the adjacent vertebral body were recorded.ResultsThe injection amount of bone cement in the observation group and control group were (4.53±0.45) mL and (4.49±0.57) mL, respectively, showing no significant difference between the two groups (t=1.018, P=0.310). Patients in both groups were followed up 6-18 months (mean, 13.3 months). There were 95 cases (81.9%) and 72 cases (69.9%) of the bone cement distribution range more than 49% of the cross-sectional area of the vertebral body in the observation group and the control group, respectively, showing significant difference in the incidence between the two groups (χ2=4.334, P=0.037). The VAS score and ODI score of the postoperative time points were significantly improved compared with those before operation (P<0.05), and there were significant differences among the postoperative time points (P<0.05). The VAS score and ODI score of the observation group were significantly better than those of the control group (P<0.05) at immediate, 2 days, and 3 months after operation, and there was no significant difference between the two groups at last follow-up (P>0.05). At 1 day after operation, the cement leakage occurred in 18 cases of the observation group (8 cases of venous leakage, 6 cases of paravertebral leakage, 4 cases of intradiscal leakage) and in 22 cases of the control group (9 cases of venous leakage, 8 cases of paravertebral leakage, 5 cases of intradiscal leakage). There was no significant difference between the two groups (P>0.05). During the follow-up, 5 cases (4.3%) in the observation group, 12 cases (11.7%) in the control group had responsible vertebral refracture, and 6 cases (5.2%) in the observation group and 14 cases (13.6%) in the control group had adjacent vertebral fracture, the differences were significant (χ2=4.105, P=0.043; χ2=4.661, P=0.031).ConclusionBone cement injection with wet-sand phase in PKP is beneficial for the bone cement evenly distributed, strengthening the responsible vertebral, relieving the short-term pain after operation, decreasing the rate of responsible vertebral refracture and adjacent vertebral fracture without increasing the incidence of relevant complications and can enhance the effectiveness.

    Release date:2020-04-29 03:03 Export PDF Favorites Scan
  • The chain mediating role of social support and resilience in the relationship between symptom burden and psychological distress among lung cancer patients in the diagnostic phase

    ObjectiveTo investigate the current status of symptom burden and psychological distress among lung cancer patients in the diagnostic phase, and to explore the chain mediating role of social support and resilience between symptom burden and psychological distress. MethodsThe patients with lung cancer in the diagnostic phase who were treated in the Department of Thoracic Surgery of the Second Xiangya Hospital of Central South University from October 2022 to June 2023 were investigated by a general information questionnaire using the MD Anderson Symptom Inventory, the Social Support Rating Scale, the Connor-Davidson Resilience Scale, and the Distress Thermometer. The chain mediating role of social support and resilience between symptom burden and psychological distress was analyzed. ResultsA total of 413 lung cancer patients were enrolled, including 173 males and 240 females, aged (54.69±10.82) years. The detection rate of psychological distress among lung cancer patients in the diagnostic phase was 48.18%, and the average score was (3.84±2.50) points. Psychological distress was positively correlated with symptom burden (P<0.01), and negatively correlated with social support and resilience (P<0.01). The mediating effect of resilience between symptom burden and psychological distress was significant. The chain mediating effect of social support and resilience between symptom burden and psychological distress was also significant. ConclusionLung cancer patients in the diagnostic phase have a high detection rate of psychological distress. Symptom burden can directly impact psychological distress, and can affect psychological distress through the indirect path of resilience as well as the chain mediating path between social support and resilience among lung cancer patients in the diagnostic phase.

    Release date:2025-05-30 08:48 Export PDF Favorites Scan
  • Mediating effect of phase angle between muscle strength and muscle function in patients with maintenance hemodialysis

    Objective To investigate the mediating effect of phase angle between muscle strength and muscle function in maintenance hemodialysis (MHD) patients, aiming to provide a reference basis for clinical improvement of muscle strength and muscle function in MHD patients. Methods Random sampling was used to collect patients undergoing outpatient MHD in the Wenjiang Hemodialysis Room of the Department of Nephrology, West China Hospital, Sichuan University between September and December 2023 as the subjects of this study. Muscle strength was assessed by handgrip strength, muscle function was assessed by Short Physical Performance Battery (SPPB), and phase angle was measured by bioelectrical impedance analysis. The mediating effect of phase angle between muscle strength and muscle function was analyzed. Results A total of 239 MHD patients were included, including 125 males (52.3%) and 114 females (47.7%). The mean phase angle of MHD patients was (5.77±1.17)°, 89 patients (37.2%) showed decreased muscle strength, and 109 patients (45.6%) showed muscle hypoplasia. Spearman’s correlation analyses showed that phase angle was significantly and positively correlated with both handgrip strength and SPPB in MHD patients (P<0.001). The results of mediation effect analysis showed that handgrip strength was able to positively predict phase angle (β=0.535, P<0.001); handgrip strength was able to positively predict SPPB (β=0.481, P<0.001); phase angle was able to positively predict SPPB (β=0.296, P<0.001); and when both handgrip strength and phase angle entered in the regression equation, both handgrip strength (β=0.392, P<0.001) and phase angle (β=0.165, P<0.05) could positively predict SPPB. Phase angle in MHD patients partially mediated the association between muscle strength and muscle function, with the mediating effect accounting for 32.5% of the total effect. Conclusions There is a close relationship between phase angle, muscle strength and muscle function in MHD patients, and muscle strength can affect muscle function directly or indirectly through phase angle. Medical professionals should pay attention to the muscle function of MHD patients and further improve their muscle function by improving their phase angle and muscle strength.

    Release date:2025-07-29 05:02 Export PDF Favorites Scan
  • Research on mental fatigue information transmission integration mechanism based on theta-gamma phase amplitude coupling

    Mental fatigue is a subjective fatigue state caused by long-term brain activity, which is the core of health problems among brainworkers. However, its influence on the process of brain information transmission integration is not clear. In this paper, phase amplitude coupling (PAC) between theta and gamma rhythm was used to study the electroencephalogram (EEG) data recorded before and after mental fatigue, so as to explain the effect of mental fatigue on brain information transmission mechanism. The experiment used a 4-hour professional English reading to induce brain fatigue. EEG signals of 14 male undergraduate volunteers before and after mental fatigue were recorded by Neuroscan EEG system. Phase amplitude coupling value was calculated and analyzed. t test was used to compare the results between two states. The results showed that theta phase of more than 90% of the electrodes in the whole brain area jointly modulated gamma amplitude of the right central area and the right parietal area, and the coupling effect among different brain regions significantly decreased (P < 0.05) when participants had felt mental fatigue. This paper shows that phase amplitude coupling can explain the influence of mental fatigue on information transmission mechanism. It could be an important indicator for mental fatigue detection. On the other hand, the results also provide a new measure to evaluate the effect of neuromodulation in relieving mental fatigue.

    Release date:2018-10-19 03:21 Export PDF Favorites Scan
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