ABSTRACT
<p><b>OBJECTIVE</b>To develop a near-infrared fluorescence imaging system based on the fluorescence properties of methylene blue.</p><p><b>METHODS</b>According to the optical properties of methylene blue, we used a custom-made specific LED light source and an interference filter, a CCD camera and other relevant components to construct the near-infrared fluorescence imaging system. We tested the signal-to-background ratio (SBR) of this imaging system for detecting methylene blue under different experimental conditions and analyzed the SBR in urine samples collected from 15 Wistar rats with intravenous injection of methylene blue at the doses of 0, 1.4, 1.6, 1.8, or 2.0 0 mg/kg methylene blue.</p><p><b>RESULTS</b>The SBR of this imaging system for detecting methylene blue was affected by the concentration of methylene blue and the distance from the sample (P<0.05). In the urine samples from Wistar rats, the SBR varied with the the injection dose, and the rats injected with 1.6 mg/kg methylene blue showed the highest SBR (8.71∓0.20) in the urine (P<0.05).</p><p><b>CONCLUSION</b>This near-infrared fluorescence imaging system is useful for fluorescence detection of methylene blue and can be used for real-time recognition of ureters during abdominal surgery.</p>
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the differences in dielectric properties (relative permittivity and conductivity) between the mucosal surface and serosal surface of malignant colorectal tissues, adjacent tissues at 1 cm and 3 cm from the tumor focus and normal colorectal tissues.</p><p><b>METHODS</b>The dielectric properties of the mucosal and serosal surface of malignant colorectal tissues, adjacent tissues (1 cm and 3 cm) and normal colorectal tissues from 39 patients with colorectal cancer were measured with an open-ended coaxial probe within the frequency range of 50 MHz-3 GHz, and the corresponding dielectric properties were analyzed respectively; statistical tests of the data were used to analyze the dielectric properties at 6 specific frequency points.</p><p><b>RESULTS</b>The dielectric properties were significantly higher in the malignant mucosa surface than in the adjacent tissues and normal colorectal tissues at the 6 specific frequency points (P<0.01). The dielectric properties decreased progressively in adjacent tissues at 1 cm and 3 cm and normal mucosa surface. The mucosal and serosal surface of malignant tissues showed significant differences in dielectric properties at 64 MHz, 128 MHz, 298 MHz, 433 MHz, and 915 MHz (P<0.01) but not at 2450 MHz (P>0.01), but such differences were not observed in normal tissues (P>0.01).</p><p><b>CONCLUSION</b>The dielectric properties of the mucosal surface of the mucosal decrease in the order of malignant colorectal tissue, adjacent tissues at 1 cm and 3 cm from the tumor foci and normal colorectal tissues. The dielectric properties are higher in the mucosal surface than in the serosal surface in the malignant tissue, but comparable in normal colorectal tissues.</p>
ABSTRACT
<p><b>OBJECTIVE</b>To achieve differential diagnosis of normal and malignant gastric tissues based on discrepancies in their dielectric properties using support vector machine.</p><p><b>METHODS</b>The dielectric properties of normal and malignant gastric tissues at the frequency ranging from 42.58 to 500 MHz were measured by coaxial probe method, and the Cole?Cole model was used to fit the measured data. Receiver?operating characteristic (ROC) curve analysis was used to evaluate the discrimination capability with respect to permittivity, conductivity, and Cole?Cole fitting parameters. Support vector machine was used for discriminating normal and malignant gastric tissues, and the discrimination accuracy was calculated using k?fold cross?</p><p><b></b>VALIDATION</p><p><b>RESULTS</b>The area under the ROC curve was above 0.8 for permittivity at the 5 frequencies at the lower end of the measured frequency range. The combination of the support vector machine with the permittivity at all these 5 frequencies combined achieved the highest discrimination accuracy of 84.38% with a MATLAB runtime of 3.40 s.</p><p><b>CONCLUSION</b>The support vector machine?assisted diagnosis is feasible for human malignant gastric tissues based on the dielectric properties.</p>
ABSTRACT
Some research on intelligent non-invasive temporary pacemakers is introduced in this paper. An industrial computer, some IC chips and other elements are used to construct its hardware, and its software is in C++ language. The experimental device has some intelligent functions of recognizing some arrhythmia. The system has a pacemaker module and an ECG monitor module. Its software includes a main program, a RS-232C communication program, a printer VxD, a pacing control VxD and ECG signal pretreatment and recognizing program and so on. The pacing-generating circuit is employed to make the precision control of pacing current. The communication between industrial-computer system and ECG module is completed through the DLL. The real time processing of ECG signals is based on filter method for a higher recognizing ratio. The system calculates several parameters to recognize certain arrhythmia and uses MIT/BIH database to validate the reliability of ECG recognition.
Subject(s)
Humans , Algorithms , Arrhythmias, Cardiac , Diagnosis , Therapeutics , Artificial Intelligence , Echocardiography , Equipment Design , Pacemaker, Artificial , Classification , Signal Processing, Computer-Assisted , Software DesignABSTRACT
This paper presents a high voltage generator for the defibrillator.Its principle and design method are introduced.The high voltage generator is the core part of the defibrillator which is necessary toany hospital.There is nodomestic-patented defibrillator by now and published paper specialized in the principle and design method of the high voltage generator for the defibrillator.