[Show abstract][Hide abstract] ABSTRACT: Based on the 32-bit ultra low power microcontroller STM32L151RBT6 using ARM Cortex-M3 kernel, the portable ambulatory blood pressure monitor powered by two AA batteries was designed. In order to insure the stability of power supply and prevent overpressure of cuff, super capacitor technology and new kind of safety logic circuits were used. The experimental result shows that: this solution is accurate and stable, which has high safety coefficient and a great clinical application value.
No preview · Article · Sep 2014 · Zhongguo yi liao qi xie za zhi = Chinese journal of medical instrumentation
[Show abstract][Hide abstract] ABSTRACT: In order to achieve the simultaneous monitoring of multiple physiological signals and finish the real-time storage and transmission of data, this paper presents a multi-parameter physiological signal monitoring system based on Cortex-M3. The system uses high-capacity SD card for data storage and USB for data transmission, which achieves synchronous storage and display. In addition, it reduces the operating frequency to achieve the goal of low power consumption .The experimental results show that the system is characterized by high-capacity, low-power and high accuracy, which meets the user's requirements for physiological signal monitoring.
[Show abstract][Hide abstract] ABSTRACT: Around the features of low power and high integration of portable electronic medical equipment design, the primary low power MCU series from the current semiconductor manufacturers were compared. The analysis results showed that the 32-bit MCUs based on the low cost and high energy efficient ARM Cortex-M architectures, have comprehensive advantages on power level, operational performance and integrated peripherals obviously.
No preview · Article · May 2014 · Zhongguo yi liao qi xie za zhi = Chinese journal of medical instrumentation
[Show abstract][Hide abstract] ABSTRACT: A highly sensitive in-situ turbidity sensor with the low power consumption was proposed and evaluated in this study. To meet the practical requirements of the in-situ detection, we have designed the light scattering path, watertight mechanical structure, and ultra-weak scattering light detecting method. Experiments showed that the sensor had a sensitivity of 0.0076 FTU with the concentration range of 0–25 FTU and the R-square of 0.9999. The sensor could withstand the water pressure in depth of 1000 m and had the low power consumption in the active mode 10.4 mA, sleep mode 65 μA with a supply voltage of 8.4 V. Southern China Sea buoy experiments indicated that the sensor could work well in the actual in-situ environment. In comparison with sensors of other companies, our sensor had relatively more comprehensive performance.
[Show abstract][Hide abstract] ABSTRACT: Recurrence and metastasis are associated with poor prognosis in hepatocellular carcinoma even in the patients who have undergone radical resection. Therefore, effective treatment is urgently needed for improvement of patients' survival. Previously, we reported that nanosecond pulse electric fields (nsPEFs) can ablate melanoma by induction of apoptosis and inhibition of angiogenesis. This study aims to investigate the in vivo ablation strategy by comparing the dose effect of nanosecond electric fields in vitro and in vivo on hepatocellular carcinoma.
Four hepatocellular carcinoma cell lines HepG2, SMMC7721, Hep1-6, and HCCLM3 were pulsed to test the anti-proliferation and anti-migration ability of 100 ns nsPEFs in vitro. The animal model of human subdermal xenograft HCCLM3 cells into BALB/c nude mouse was used to test the anti-tumor growth and macrophage infiltration in vivo.
In vitro assays showed anti-tumor effect of nsPEFs is dose-dependant. But the in vivo study showed the strategy of low dose and multiple treatments is superior to high dose single treatment. The macrophages infiltration significantly increased in the tumors which were treated by multiple low dose nsPEFs.
The low dose multiple nsPEFs application is more efficient than high dose single treatment in inhibiting the tumor volume in vivo, which is quite different from the dose-effect relationship in vitro. Beside the electric field strength, the macrophage involvement must be considered to account for effect variability and toxicology in vivo.
[Show abstract][Hide abstract] ABSTRACT: Hepatocellular carcinoma (HCC) is a highly aggressive malignancy. Nanosecond pulsed electric field (nsPEF) is a new technology destroying tumor cells with a non-thermal high voltage electric field using ultra-short pulses. The study's aim was to evaluate the ablation efficacy of nsPEFs with human HCC cell lines and a highly metastatic potential HCC xenograft model on BALB/c nude mice. The in vivo study showed nsPEFs induced HCC cell death in a dose dependent manner. On the high metastatic hepatocellular carcinoma cell line (HCCLM3) xenograft mice model, tumor growth was inhibited significantly in nsPEF-treated- groups (single dose and multi-fractionated dose). Besides a local effect, the nsPEF treatment reduced pulmonary metastases. The nsPEFs also enhanced HCC cell phagocytosis by human macrophage cell (THP1) in vitro. The nsPEF is efficient in controlling HCC progression and reducing its metastasis. NsPEF treatment may elicit a host immune response against tumor cells. This study suggests nsPEF therapy could be used as a potential locoregional therapy for hepatocellular carcinoma.
[Show abstract][Hide abstract] ABSTRACT: The diagnosis of sleep apnea syndrome (SAS) has a significant importance in clinic for preventing diseases of hypertention, coronary heart disease, arrhythmia and cerebrovascular disorder, etc. This study presents a novel method for SAS detection based on single-channel electrocardiogram (ECG) signal. The method preprocessed ECG and detected QRS waves to get RR signal and ECG-derived respiratory (EDR) signal. Then 40 time- and spectral-domain features were extracted to normalize the signals. After that support vector machine (SVM) was used to classify the signals as "apnea" or "normal". Finally, the performance of the method was evaluated by the MIT-BIH Apnea-ECG database, and an accuracy of 95% in train sets and an accuracy of 88% in test sets were achieved.
No preview · Article · Oct 2013 · Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi
[Show abstract][Hide abstract] ABSTRACT: In-situ colored dissolved organic matter (CDOM) detection has great significance for marine scientific research. In this work, we have developed and tested a highly sensitive in-situ CDOM sensor. With the detecting principle and in-situ survey requirement, we have designed the conjugate focus light path, watertight mechanical structure and high precision electrical system with low power consumption. The baseline noise and calibration experiments indicated that the sensor had a sensitivity of 0.162μg/L. When the sensor is set at sleep mode, it consumes only 90μA with 9V power supply. These characters meet the in-situ survey requirement well.
[Show abstract][Hide abstract] ABSTRACT: In situ monitoring of nitrate in respect of improvement of accuracy becomes more and more important. The direct spectrophotometer analysis of aqueous nitrate is a simple analytic procedure but prone to interferences. In order to solve this problem, the Least Area Value (LAV) Model for in situ determining nitrate in the ocean is reported. The absorbance response of the LAV model varies linearly with concentrations.Calculations of it are in excellent much higher accuracy than conventional measurement models.And more, it solves the problem without the need to measure the dark current first. This eliminated errors due to changes in the dark current during periods shortly after the instrument was turned on. The noise is nearly random and significant reductions in the detection limit are possible by averaging multiple observations in this model. The measurements were directly taken after dilution of the samples between 0.1 mu mol/1 and 400 mu mol/l.The model was checked on and applied to real samples.The results show that this approach is suitable for routine field measurements of nitrate, which has achieved the precision of 99% and the stability of 99.5%. The model is simple, rugged. The precision, accuracy and stability of the concentrations are sufficiently used to support for many studies.
[Show abstract][Hide abstract] ABSTRACT: A highly sensitive and reliable chlorophyll sensor is proposed and evaluated to meet the demand of in-situ chlorophyll detection. As the major innovation, pseudo-random sequence modulation is introduced into the amplitude measurement of the fluorescence for the first time. Compared with the conventional single frequency square wave modulation, the pseudo-random sequence modulation could spread the spectrum of the fluorescence, and improve the sensitivity and the interference suppression ability of the sensor without increasing the complexity of the system's hardware. The sensitivity experiments show that the sensor could detect chlorophyll as low as 0.0103 μg/L, with the concentration range of 0~25 μg/L and the R-square of 0.9998. In the interference suppression test, for the same interference in the passing band, the maximum response of the 31 bits PRS modulation system is 2.3 times smaller than that of the single frequency square wave modulation system.
No preview · Article · Aug 2013 · IEEE Transactions on Instrumentation and Measurement
[Show abstract][Hide abstract] ABSTRACT: An instrument is proposed for nitrate in situ monitoring in deep sea. It consists of a UV spectrophotometer, a deuterium lamp of high stability and low power consumption, a rugged and high-throughput retro-reflection probe and a center control board with large data storage capacity. With a measurement precision of nitrate concentration of 1 mu mol/l and a resolution of 0.5 mu mol/l, the instrument is able to measure nitrate concentrations from 0.5 mu mol/l to 320 mu mol/l. The system can automatically deduct the dark current to rectify the effect of temperature drift and correct the overall absorbance drift caused by instrument drift through integration of relative absorbance (MA) algorithm. The system can endure the pressure at up to 1500m deep sea and carry out automatic long-term in situ detection of nitrate with high stability without needs for any manual intervention.
[Show abstract][Hide abstract] ABSTRACT: As one of the major propulsion plants of marine system, the controllable pitch propeller (CPP) has been widely applied in dynamic systems of a variety of ships at present. Both the operations on CPP from crew and the CPP's actual working state are closely related to safe and successful navigations. Aiming at this fact, a novel data logger based on embedded platform and field bus was designed and developed, which can meet the requirements of long-playing, online, continuous collecting and recording the information of operator's commands on CPP and CPP's working state with the actual time. These data that could be read and analyzed by authorized staff when necessary can provide convincing evidence for accident analysis and equipment maintenance. A practical data cache technology and power-down data integrity protection mechanism are also mentioned in this article. The test results indicated that this data logger, which can work continuously for more than 50 days in general case if the operator does not want any data to be overwritten, has high reliability and great practical value.
[Show abstract][Hide abstract] ABSTRACT: A multi-parameter monitoring system mainly includes invasive blood pressure, PPG and electrocardiogram was designed. We analyzed these signals and extracted some parameters from them, such as SpO2, PPGA, RC, AR, Ps, Pd, Pm, IBPA, IBPI, R and C, which are provided as bases for judgment of doctors. A validation clinical experiment was analyzed, and the results confirmed that the system realized the monitoring of cardiovascular parameters during anesthesia.
[Show abstract][Hide abstract] ABSTRACT: This paper presents a novel method for automatic identification of motion artifact beats in ECG recordings. The proposed method is based on the ECG complexes clustering, fuzzy logic and multi-parameters decision. Firstly, eight simulated datasets with different signal-to-noise ratio (SNR) were built for identification experiments. Results show that the identification sensitivity of our method is sensitive to SNR levels and acts like a low-pass filter that matches the cardiologists' recognition, while the Norm FP rate and PVB FP rate keep significantly low regardless of SNR. Furthermore, a simulated dataset including random durations of motion activities superimposed segments and two clinical datasets acquired from two different commercial recorders were adopted for the evaluation of accuracy and robustness. The overall identification results on these datasets were: sensitivity >94.69%, Norm FP rate <0.60% and PVB FP rate <2.65%. All the results were obtained without any manual threshold adjustment according to the priori information, thus dissolving the drawbacks of previous published methods. Additionally, the total cost time of our method applied to 24 h recordings is less than 1 s, which is extremely suitable in the situation of magnanimity data in long-term ECG recordings.
No preview · Article · Mar 2012 · Annals of Biomedical Engineering
[Show abstract][Hide abstract] ABSTRACT: A wireless implantable sensor network system (WISNS) is designed for in vivo monitoring physiological signals of a population of animals. WISNS can simultaneously monitor more than 15 animals, communicating three kinds of analog information among sensor nodes. Analog signals are transmitted to relay node at 800-KHz carrier by AM. Relay nodes digitalize and package them into messages, and then forward to the Wireless sensor network by Nordic RF technology (NWSN). Smaller overall dimensions (<2 cm (3)), lower power regulation, and dedicated packaging make the system suitable and compatible for implantable devices. The implantable sensor node, protocol stack of NWSN, and performance of the system are evaluated and optimized with ECG monitoring test of rats. Compared with those commercially available sensor nodes, our implantable one is leading in the weight and volume miniaturization, and our WISNS solution shows huge potential in achieving the compatibility of different animals.
No preview · Article · May 2011 · IEEE transactions on information technology in biomedicine: a publication of the IEEE Engineering in Medicine and Biology Society
[Show abstract][Hide abstract] ABSTRACT: Automatic detection of atrial fibrillation (AF) for AF diagnosis, especially for AF monitoring, is necessarily desirable for clinical therapy. In this study, we proposed a novel method for detection of the transition between AF and sinus rhythm based on RR intervals. First, we obtained the delta RR interval distri bution difference curve from the density histogram of delta RR intervals, and then detected its peaks, which represented the AF events. Once an AF event was detected, four successive steps were used to classify its type, and thus, determine the boundary of AF: 1) histogram analysis; 2) standard deviation analysis; 3) numbering aberrant rhythms recognition; and 4) Kolmogorov-Smirnov (K-S) test. A dataset of 24-h Holter ECG recordings (n = 433) and two MIT-BIH databases (MIT-BIH AF database and MIT-BIH nor mal sinus rhythm (NSR) database) were used for development and evaluation. Using the receiver operating characteristic curves for determining the threshold of the K-S test, we have achieved the highest performance of sensitivity and specificity (SP) (96.1% and 98.1%, respectively) for the MIT-BIH AF database, compared with other previously published algorithms. The SP was 97.9% for the MIT-BIH NSR database.
No preview · Article · May 2011 · IEEE Transactions on Biomedical Engineering
[Show abstract][Hide abstract] ABSTRACT: Photoplethysmography (PPG) is an effective technique that can be used to detect blood volume changes in the microvascular bed of tissue. However, when the patients are in poor perfusion, the signal of PPG will be too weak to detect. So a dynamic variable amount of light detection method is designed to solve the problem. The method adjusts the hardware and software of original method. By using this method, the detector can detect the waveform of PPG more effectively, and greatly improve the accuracy of measurement. It has been used in clinical studies of surgical anesthesia, and achieved very good results.
[Show abstract][Hide abstract] ABSTRACT: Photoplethysmogram (PPG) of pulse wave has been proposed for analgesia monitoring recently with most attentions paid to its magnitude and little attention to its morphology. Therefore, effect of nociceptive stimuli on the morphology of PPG was studied using a morphological parameter named area ratio (AR). Fifty patients, ASA I or II, scheduled for laparoscopy surgery under general anaesthesia were enrolled. They were anaesthetized using propofol and remifentanil, and their PPG signals were recorded. Tracheal intubation was used as a nociceptive stimulus. Off-line analysis showed that the morphology of PPG was influenced by the intubation. The AR increased during intubation and returned to the initial level. Its distributions before intubation (0.687±0.153) and during intubation (0.862± 0.125) were very highly significantly different (P