Objective To compare and analyze the performance indexes and the imaging quality of the home and imported X-ray machines through testing their partial imaging performance parameters. Methods By separate sampling from 10 home and 10 imported X-ray machines, the parameters including tube current, time of exposure, machine total exposure, and repeatability were tested, and the imaging performance was evaluated according to the national standard. Results All the performance indexes met the standard of GB4505-84. The first sampling tests showed the maximum changing coefficient of imaging performance repeatability of the home X-ray machines was ?max1=0.025,while that of the imported X-ray machine was ?max1=0.016. In the second sampling tests, the maximum changing coefficients of the two were ?max2=0.048 and ?max2=0.022, respectively. Conclusion The 2 years′ follow-up tests indicate that there is no significant difference between the above-mentioned parameters of the elaborately adjusted home X-ray machines and imported ones, but the home X-ray machines are no better than the imported X-ray machines in stability and consistency.

Objective To definite the status of tone of autonomic nervous system during water immersion process by analyzing the nonlinear characteristic of ECG signals;To explore the relation of approximate entropy(ApEn),scaling exponent(?) changes and modulation function status of autonomic nervous system.Methods The ECG signals of rats during the process of restraint stress(RS),water-immersion restraint stress(WRS) and Vagotomy and Water-immersion restraint stress(vagotomy-WRS) were recorded.The ApEn and ? of RR intervals were calculated.Results After the stress,the differences of the value of ApEn and ? of RR intervals between RS and vagotomy-WRS groups and between different periods in vagotomy-WRS group were not significant.The value of ApEn increased in WRS group and decreased in RS group significantly.Compared with pre-stress,? showed decreased trend,all of the values smaller than 0.5 in WRS group and increased obviously,most values larger than 0.5 in RS group.Conclusion The increased ApEn and decreased ? indicates a higher intensity of parasympathetic activity.The parasympathetic activity is the predominant response of autonomic nervous system during water immersion process.

This paper introduces the application of H7279intelligent display chip to the selection and display of different kinds of analog electrocardiogram output by the analog electrocardiogram generator controlled by a single chip micyoco(SCM).

In this study, ECG signals of normal sinus rhythm (NSR), ventricular tachycardia (VT) and ventricular fibrillation (VF) were taken out to extract the RR interval series. Approximate entropy (ApEn) values of the RR interval series were calculated and compared among the three groups by ANOVA methods. It was found that the values of ApEn were increased significantly from NSR to VT and then to VF. Approximate entropy may be regarded as an index to discriminate the ECG signals of different state.
Electrocardiography ; methods ; Entropy ; Humans ; Signal Processing, Computer-Assisted

OBJECTIVE: To establish an animal model of myocardial ischemia with blood stasis syndrome in mini-swines. METHODS: An animal model of myocardial ischemia was established in mini-swines by oppressing the coronary artery through the expansion of inner layer of Ameroid constrictor and the Ameroid constrictor was implanted into the distal end of the initial part of the first branch of interventricular septum of ramus descendens anterior arteriae coronariae sinistrae. Dynamic observation of behavior changes, general health status and changes of hemorheological parameters in the mini-swines were made after operation. RESULTS: The coronary angiography showed that the stenosis rate in ischemic group was more than 75% four weeks after operation. Compared with before operation and sham-operated group, there were great changes of behavior, general health status, tongue color and hemorheological parameters in ischemic group (P<0.05). CONCLUSION: The animal model of myocardial ischemia with blood stasis syndrome in mini-swines was established successfully 4 weeks after operation. The pathological process in the animal model is similar to that in the patients with chronic myocardial ischemia. So this model can be adopted in the research of myocardial ischemia with blood stasis syndrome.

OBJECTIVEIn order to accurately reconstruct the acoustic source image, the application of transducer's receiving characteristics in magneto-acoustic tomography with magnetic induction (MAT-MI) is studied.

METHODSThe conductivity phantom model is built, and the magnetic acoustic signals are simulated and the acoustic sources are reconstructed according to the transducer's receiving characteristics.

RESULTSThe reconstructed image of acoustic source is consistent with the topographic shape and size of the phantom model.

CONCLUSIONMAT-MI based on the transducer's characteristics lays the foundation for further study.

Chaos and fractals are ubiquitous phenomena of nature. A system with fractal structure usually behaves chaos. As a complicated nonlinear dynamics system, heart has fractals structure and behaves as chaos. The deeper inherent mechanism of heart can be opened out when the chaos and fractals theory is utilized in the research of the electrical activity of heart. Generally a time series of a system was used for describing the status of the strange attractor of the system. The indices include Poincare plot, fractals dimension, Lyapunov exponent, entropy, scaling exponent, Hurst index and so on. In this article, the basic concepts and the methods of chaos and fractals were introduced firstly. Then the applications of chaos and fractals theories in the study of electrocardial signal were expounded with example of how they are used for ventricular fibrillation.
Electrocardiography ; methods ; Fractals ; Humans ; Nonlinear Dynamics ; Signal Processing, Computer-Assisted ; Stochastic Processes

BACKGROUND:Deep vein thrombosis is a common postoperative complication after spinal surgery in clinical department of neurosurgery anddepartment of orthopedics. Deep vein thrombosis is mostly related to vein intima injury, stasis and activation of blood coagulation factor. Early effective prediction can effectively avoid the adverse effects on the prognosis of patients with deep vein thrombosis. D-dimer used in the prediction of deep venous thrombosis has high sensitivity and specificity, andcan be used as a sensitive predictor for deep vein thrombosis. OBJECTIVE:To explore the relationship between plasma D-dimer mass concentration and deep vein thrombosis after spinal surgery. METHODS:A total of 83 patients treated with spinal surgery colected fromDepartment of Neurosurgery, First Affiliated Hospital of Xinjiang Medical University from April 2014 to August 2015 were retrospectively analyzed. They were divided into two groups according to postoperative plasma D-dimer mass concentration:D-dimer positive group (n=48) and D-dimer negative group (n=35). We monitored D-dimer mass concentration in both groups preoperatively and postoperatively 1, 3, 5, 9 and 14 days, and analyzed the relationship between D-dimer mass concentration and deep vein thrombosis. RESULTS AND CONCLUSION:(1) No significant difference in D-dimer mass concentration was determined between the two groups (P> 0.05). D-dimer mass concentration was significantly higher in the D-dimer positive group than in the D-dimer negative group 1, 3, 5, 9, and 14 days postoperatively (P<0.05). (2) After operation, plasma D-dimer of 28 cases was positive, with persistent increasing. Double lower limb deep vein color Doppler ultrasound demonstrated that seven patients experienced deep vein thrombosis and four patients suffered from pulmonary embolism in D-dimer positive group. There was no deep vein thrombosis and pulmonary embolism in the D-dimer negative group. (3) These results indicate that positive D-dimer concentration of patientsafter spinal surgery suggests the possibility of deep vein thrombosis. If the concentration of D-dimer is persistently high, we should highly alert to the occurrence of deep vein thrombosis.

The relatively high abundance of geochemical elements such as Nb, Zr, Y and other elements shows serious interferences in the determination of trace silver in geochemical samples by inductively coupled plasma-mass spectrometry ( ICP-MS) . Thus it will lead to large deviation in the determination of geochemical samples without separation and enrichment. The traditional emission spectrum or graphite furnace atomic absorption method is only single-element analysis to the silver and with bad sample representativeness. In this study, load diphenylthiourea ( DPTU) foam selective enrichment was used for the separation of Au and Ag from other interfering elements in geological samples, and thiourea liberation-ICP-MS method was developed for the simultaneous determination of Au and Ag. The samples were first decomposed by 1:1 aqua regia. After addition of 50 mL of water, the samples were adsorbed under oscillation for 30 min at 20℃. The detection limits of the Au and Ag were 0. 02 ng/g and 0. 007μg/g, respectively. The proposed method was successfully applied to the determination of Au and Ag in eight national standard materials.

Objective To evaluate the therapeutic effect of catheter-directed thrombolysis (CDT) for the treatment of acute deep venous thrombosis (DVT) of the lower extremity.Methods Clinical data of 195 patients of acute DVT treated by CDT and adjunctive angioplasty and stenting from August 2010 to February 2014 were analyzed retrospectively.CDT by antegrade puncture of popliteal vein,CDT by great saphenous vein and CDT by retrograde puncture of contralateral femoral vein were used in these cases.Venous recanalization was graded by a thrombus score based on pre-and post-treatment venography.Results Technique success rate,clinical success rate,in popliteal vein group,great saphenous vein group and contralateral femoral vein group were 94.6％,72.2％ and 90.3％,97.3％,83.3％,and 90.0％.Patent rate of deep venous,patent rate of stenting and mild post-thrombotic syndrome (PTS) rate were 88.6％,66.7％ and 75.0％,83.3％,57.1％ and 88.9％,8.3％,26.7％ and 20.8％.Conclusion CDT by antegrade puncture of popliteal vein group combined with adjunctive angioplasty and stenting is safe and effective with higher clinical success rate and better long term results than other approaches for the treatment of DVT patients.