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find Keyword "model" 900 results
  • Establishment of a risk nomogram model for predicting the excitatory response of vagus nerve in patients with functional epilepsy after radiofrequency thermocoagulation

    ObjectiveTo investigate the establishment of a risk nomogram model for predicting vagus excitatory response in patients with functional epilepsy after radiofrequency thermocoagulation.MethodsA total of 106 patients with epilepsy admitted to the neurosurgery department of our hospital from January 2016 to June 2020 were selected and divided into the Vagus excitatory response (VER) group and the non-VER group according to their occurrence or absence. Logistic regression analysis was used to screen out the risk factors of VER during SEEG-guided Percutaneous radiofrequency thermocoagulation (PRFT) in patients with functional epilepsy, and R software was used to establish a histogram model affecting VER in SEEG-guided PRFT. Bootstrap method was used for internal verification. C-index, correction curve and ROC curve were used to evaluate the prediction ability of the model.ResultsLogistic regression analysis showed that age [OR=0.235, 95%CI (0.564, 3.076)], preoperative fugl-meyer score [OR=4.356, 95%CI (1.537, 6.621)], depression [OR=0.995, 95%CI (1.068, 7.404)], and lesion range [OR=1.512, 95%CI (0.073, 3.453)] were independent risk factors for the occurrence of VER in PRFT under the guidance of SEEG (P<0.05), and were highly correlated with the occurrence of VER in PRFT. Based on the above six indicators, a SEEG-guided colograph model of VER risk in PRFT was established, and the model was validated internally. The results showed that the C-index of the modeling set and validation set were 0.779 [95%CI (0.689, 0.869)] and 0.782 [95%CI (0.692, 0.872)], respectively. The calibration curves of the two groups fit well with the standard curves. The areas under the ROC curve (AUC) of the two groups were 0.779 and 0.782 respectively, which proved that the model had good prediction accuracy.ConclusionFor patients with functional epilepsy requiring seeg-guided PRFT therapy, age, preoperative Fugl-meyer score, depression and lesion range should be taken into full consideration to comprehensively assess the incidence of VER, and early intervention measures should be taken to reduce and reduce the incidence, which has good clinical application value.

    Release date:2021-08-30 02:33 Export PDF Favorites Scan
  • Purified retinal ganglion cells cultured in serum-free neurobasal medium

    Objective To establish a purified model of rat retinal ganglion cells (RGCs) cultured by serum-free medium,and provide a good cell model to investigate the damage of RGCs in glaucoma,retinal ischemia,and degenerative retinopathy. Methods Two monoclonal antibodies,anti-rat SIRP(OX-41)against rat macrophage and antibody against rat Thy-1(OX-7),were used to purify and characterize RGCs from 1-3-day old Sprague-Dawley(SD)rats by means of two-step filtration.Purified RGCs were cultured in serum-free neurobasal medium containing B27 and ciliary neurotrophic factor(CNTF) meeting the neuronal cellrsquo;s special requirements.Photomicrographs illustration,immunfluorescence staining of Thy-1,calcein-acetoxymethyl ester(calcein-AM)fluorescence images were used to observe and identify cultured retinal cells and purified RGCs. Results Among the primary cultured rat retinal cells,91% were retinal neurons.Protuberances of RGCs were seen after cultured for 24 hours.At the4th to 8th day,many cells had uniform configuration,large body,and long protuberances. At the 14th day,over 60% cells maintained viability.Immunoflurescence staining of Thy-1 showed the purity of RGCs was about 90%. The results of calcein-AM staining,which stained the living cells only,showed large cell body of RGCs and most of RGCs had a protuberance whose length was twice longer than the diameter of the cells. Conclusion RGCs cultured by serum-free medium has uniform size,good configuration,and high purity,which is adapt to the research of damage of RGCs caused by various factors and to evaluate the protective effects of neuroprotective agents. (Chin J Ocul Fundus Dis, 2006, 22: 200-203)

    Release date:2016-09-02 05:51 Export PDF Favorites Scan
  • Comparison of two methods for preparing knee osteochondral injury models in mice

    ObjectiveTo observe the effect of using tungsten drills to prepare mouse knee osteochondral injury model by comparing with the needle modeling method, in order to provide an appropriate animal modeling method for osteochondral injury research.MethodsA total of 75 two-month-old male C57BL/6 mice were randomly divided into 3 groups (n=25). Mice in groups A and B were used to prepare the right knee osteochondral injury models by using needles and tungsten drills, respectively; group C was sham-operation group. The general condition of the mice was observed after operation. The samples were taken at 1 day and 1, 2, 4, and 8 weeks after modeling, and HE staining was performed. The depth, width, and cross-sectional area of the injury site at 1 day in groups A and B were measured, and the percentage of the injury depth to the thickness of the articular cartilage (depth/thickness) was calculated. Toluidine blue staining and immunohistochemical staining for collagen type Ⅱ were performed at 8 weeks, and the International Cartilage Research Society (ICRS) score was used to evaluate the osteochondral healing in groups A and B.ResultsAll mice survived to the completion of the experiment. HE staining showed that group C had normal cartilage morphology. At 1 day after modeling, the injury in group A only broke through the cartilage layer and reached the subchondral bone without entering the bone marrow cavity; the injury in group B reached the bone marrow cavity. The depth, width, cross-sectional area, and depth/thickness of the injury in group A were significantly lower than those in group B (P<0.05). At 1, 2, 4, and 8 weeks after modeling, there was no obvious tissue filling in the injured part of group A, and no toluidine blue staining and expression of collagen type Ⅱ were observed at 8 weeks; while the injured part of group B was gradually filled with tissue, the toluidine blue staining and the expression of collagen type Ⅱ were seen at 8 weeks. At 8 weeks, the ICRS score of group A was 8.2±1.3, which was lower than that of group B (13.6±0.9), showing significant difference (t=−7.637, P=0.000).ConclusionThe tungsten drills can break through the subchondral bone layer and enter the bone marrow cavity, and the injury can heal spontaneously. Compared with the needle modeling method, it is a better method for modeling knee osteochondral injury in mice.

    Release date:2021-07-29 05:02 Export PDF Favorites Scan
  • EXPERIMENTAL STUDY ON SURGICAL OPERATION AND HYPOPHOSPHATEMIA

    Objective To investigate the relationship between surgical operation and hypophosphatemia, to observe the possible damage of hypophosphatemia and to assess the value of postoperative phosphate supplementation. Methods Sixty four male SD rats were randomly divided into 2 groups, Group Ⅰ, drinking a specially prepared solution to reduce their phosphate storage, Group Ⅱ, drinking water as a control. All received common bile duct ligation 3 weeks later. The serum biochemical data including phosphate level were obtained before and after operation. Then half of rats in each group were supplied with NaH2PO4 5-day survival rates were analyzed with statistic methods and their vital organs were observed under electron microscope. Results The phosphate level of each group was descended after operation. The group with phosphate shortage before operation (group Ⅰ) had a greatest fall of phosphate and average arterial pressure. The phosphate-supplied rats had a minor change of vital organs under electron microscope scan and higher 5-day survival rate compared to others in this group.Conclusion Abdominal surgery may induce postoperative hypophosphatemia, especially when the phosphate has been lacking before operation. Severe hypophosphatemia, superimposed on surgical trauma, enhances the damage to the body. Prompt supplement of phosphate will improve the prognosis of surgical operation.

    Release date:2016-09-08 02:01 Export PDF Favorites Scan
  • Design of a Multifunctional and Transparent Urinary System Model

    This article describes a novel Multifunctional and Transparent Urinary System Model (MTUSM),which can be applied to anatomy teaching, operational training of clinical skills as well as simulated experiments in vitro. This model covers kidneys, ureters, bladder, prostate, male and female urethra, bracket and pedestal,etc. Based on human anatomy structure and parameters, MTUSM consists of two transparent layers i.e. transparent organic glass external layer,which constraints the internal layer and maintains shape of the model, and transparent silica gel internal layer, which possesses perfect elasticity and deformability. It is obvious that this model is preferable in simulating the structure of human urinary system by applying hierarchical fabrication. Meanwhile, the transparent design, which makes the inner structure, internal operations and experiments visual,facilitates teaching instruction and understanding. With the advantages of simple making, high-findelity, unique structure and multiple functions, this model will have a broad application prospect and great practical value.

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  • Effect of vascular endothelial cell growth factor (VEGF) antisense oligodeoxynucleotides on expression of VEGF in rats with oxygen-induced retinopathy

    Objective To evaluate the effect of vascular endothelial cell growth factor (VEGF) antisense oligodeoxynucleotides (ASODNs) on the expression of VEGF in rats with oxygen-induced retinopathy. Methods Thirty newborn Sprague-Dawley (SD) rats were randomly divided into 3 groups:normal control group, disposal group and non-disposed group, The animal models with oxygen-induced proliferative retinopathy were established by raising the rats in hyperoxic environment. Retrobulbar injection was performed with VEGF ASODNs or normal saline on the rats in 3 groups respectively. The intraocular tissues (all the tissues except the cornea, sclera, and lens) and serum were collected, and the expressions of VEGF were determined by using competitive enzyme immunoassay.Results The expressions of VEGF in intraocular tissues of rats in disposal group were significantly lower than those in non-disposed group (P<0.05), and there was no statistical difference between the disposal and normal control group (P>0.05). There was no significant difference of the expressions of VEGF in serum of rats between the disposal and non-disposed group (P>0.05), which were both lower than those in the normal control group (P<0.05). Conclusion VEGF ASODNs could significantly inhibit the expression of VEGF in intraocular tissues. (Chin J Ocul Fundus Dis,2003,19:172-174)

    Release date:2016-09-02 06:00 Export PDF Favorites Scan
  • Dynamic continuous emotion recognition method based on electroencephalography and eye movement signals

    Existing emotion recognition research is typically limited to static laboratory settings and has not fully handle the changes in emotional states in dynamic scenarios. To address this problem, this paper proposes a method for dynamic continuous emotion recognition based on electroencephalography (EEG) and eye movement signals. Firstly, an experimental paradigm was designed to cover six dynamic emotion transition scenarios including happy to calm, calm to happy, sad to calm, calm to sad, nervous to calm, and calm to nervous. EEG and eye movement data were collected simultaneously from 20 subjects to fill the gap in current multimodal dynamic continuous emotion datasets. In the valence-arousal two-dimensional space, emotion ratings for stimulus videos were performed every five seconds on a scale of 1 to 9, and dynamic continuous emotion labels were normalized. Subsequently, frequency band features were extracted from the preprocessed EEG and eye movement data. A cascade feature fusion approach was used to effectively combine EEG and eye movement features, generating an information-rich multimodal feature vector. This feature vector was input into four regression models including support vector regression with radial basis function kernel, decision tree, random forest, and K-nearest neighbors, to develop the dynamic continuous emotion recognition model. The results showed that the proposed method achieved the lowest mean square error for valence and arousal across the six dynamic continuous emotions. This approach can accurately recognize various emotion transitions in dynamic situations, offering higher accuracy and robustness compared to using either EEG or eye movement signals alone, making it well-suited for practical applications.

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  • Application of deep neural network models to the electrocardiogram

    Electrocardiogram (ECG) is a noninvasive, inexpensive, and convenient test for diagnosing cardiovascular diseases and assessing the risk of cardiovascular events. Although there are clear standardized operations and procedures for ECG examination, the interpretation of ECG by even trained physicians can be biased due to differences in diagnostic experience. In recent years, artificial intelligence has become a powerful tool to automatically analyze medical data by building deep neural network models, and has been widely used in the field of medical image diagnosis such as CT, MRI, ultrasound and ECG. This article mainly introduces the application progress of deep neural network models in ECG diagnosis and prediction of cardiovascular diseases, and discusses its limitations and application prospects.

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  • Controlling Epileptogenic Excitation Based on Neural Mass Model

    Overexcitation of neurons in brain can lead to epilepsy seizures, and the key to control epilepsy seizures is to keep the balance between excitation and inhibition. In this paper, epileptiform index is presented to denote the seizure degree and used as control variable of PID controller to control epilepsy seizures. Neural mass model (NMM) is used as a test-bed to simulate the change of seizure degree with the increase of excitatory strength and two control strategies. Experimental results showed that the increase of excitatory strength could lead to a substantial increase of epileptiform index and trigger seizures. PID controller which is used to decrease excitatory strength or increase inhibitory strength can keep excitation-inhibition balance and inhibit epilepsy seizures. Epileptiform index can describe the linear and nonlinear feature of electroencephalogram (EEG) comprehensively, and PID controller is simple and independent of underlying physiological structure, which lays the foundation for its application in the clinic.

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  • Research on simulation and optimal design of a miniature magnetorheological fluid damper used in wearable rehabilitation training system

    The goal of this paper is to solve the problems of large volume, slow dynamic response and poor intelligent controllability of traditional gait rehabilitation training equipment by using the characteristic that the shear yield strength of magnetorheological fluid changes with the applied magnetic field strength. Based on the extended Bingham model, the main structural parameters of the magnetorheological fluid damper and its output force were simulated and optimized by using scientific computing software, and the three-dimensional modeling of the damper was carried out after the size was determined. On this basis and according to the design and use requirements of the damper, the finite element analysis software was used for force analysis, strength check and topology optimization of the main force components. Finally, a micro magnetorheological fluid damper suitable for wearable rehabilitation training system was designed, which has reference value for the design of lightweight, portable and intelligent rehabilitation training equipment.

    Release date:2023-02-24 06:14 Export PDF Favorites Scan
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