Fusion of detected multi-channel maternal electrocardiogram (ECG) R-wave peak locations.

BACKGROUND: Almost all promising non-invasive foetal ECG extraction methods involve accurately determining maternal ECG R-wave peaks. However, it is not easy to robustly detect accurate R-wave peaks of the maternal ECG component in an acquired abdominal ECG since it often has a low signal-to-noise ratio (SNR), sometimes containing a large foetal ECG component or other noises and interferences. This paper discusses, under the condition of acquiring multi-channel abdominal ECG signals, how to improve the robustness of maternal ECG R-wave peak detection. METHODS: On the basis of summarising the current single channel ECG R-wave peak detection methods, the paper proposed a specific fusion algorithm of detected multi-channel maternal ECG R-wave peak locations. The proposed entire algorithm was then tested using two databases; one database, created by us, was composed of 343 groups of 8-channel data collected from 78 pregnant women, and the other one, called the challenge database, was from the Physionet/Computing in Cardiology Challenge 2013, including 175 groups of 4-channel data. When using these databases, each group of data was classified into two parts, called the training part and the validation test part respectively; the training part was the first 8.192 s of each group of data and the validation test part was the next 8.192 s. RESULTS: To show the results, three evaluation parameters-sensitivity (Se), positive predictive value (PPV) and F1-are used. The validation test results for the database we collected are Se = 99.93 %, PPV = 99.98 %, and F1 = 99.95 %, while the results for the challenge database are Se = 99.91 %, PPV = 99.86 %, and F1 = 99.88 %. CONCLUSION: The results of the test show that the robustness of our proposed whole fusion algorithm was superior to that of other outstanding algorithms for maternal R-wave detection, and is much better than that of single channel maternal R-wave detection algorithms.

[Investigation of the enrichment and separation of lead and lead isotopes in simulated blood matrix].

The enrichment and separation method was used in the present paper to overcome the influence of matrix effect on the determination of lead concentration and isotope ratios. The patented method was used to enrich and separate the lead in simulated blood matrix; the lead concentrations and isotope ratios were determined by ICP-MS before and after enrichment and separation. The recovery rate of Pb is more than 99% through this method while the removal rate of major impurity ions such as Na, K is about 80%. The concentrations of each lead isotope decrease with the matrix concentration increasing (p < 0.001), and lead isotope ratios show no significant differences in the matrix of different concentrations. When the matrix concentration is more than 62.5 microg x mL(-1), the strength will decrease with the determination times increasing. It was concluded that the characteristics of this method are of high recovery rate (> 99%), fast, simple and convenient, and it can raise the accuracy and precision of the concentration determination of lead isotopes and has no significant influence on the accuracy of lead isotope ratios determination.

[Studies on the interaction of gatifloxacin with bovine serum albumin in the presence of carbon nanotubes by fluorescence spectroscopy].

Fluorescence spectroscopy was used to investigate the influences of carbon nanotubes (CNTs) on the fluorescence of bovine serum albumin (BSA), the influences of CNTs on that of gatifloxacin (GFLX), and the influences of GFLX on that of BSA with or without coexisting CNTs under imitated physiological condition. The experimental results demonstrate that both gatifloxacin and carbon nanotubes could quench the intrinsic fluorescence of BSA, and the quenching mechanism is mainly static quenching. The fluorescence quenching action of GFLX on BSA was weakened in the presence of CNTs. The fluorescence quenching data were analyzed according to Stern-Volmer equation and double-reciprocal Lineweaver-Burk equation. It was shown that the quenching constant (K(sv)) and the binding constant (K) are decreased with the concentration of carbon nanotubes increasing. The effects of coexisting CNTs on GFLX-BSA interactions were discussed to offer a reference for the studies on the action mechanism of CNTs or GFLX with albumins in vivo.

[The design of no-power combination manual/foot control suction apparatus].

In this paper, one kind of suction apparatus is introduced, which could use manual, foot control and control combination. The design mentality, realization method, installation constitution and application method are also described. It is suitable to the nonmotile source condition and transportation situation, adapting easily to environment, and getting into favour with the medical staff and field first-aid personnel.

[The research of the foamy fracture fixation splint].

A new production method of fracture fixation splint is introduced in the paper. The basic raw materials are multi-isocyanic acid, mixed with surfactants, catalysts, fillers, and so on. The splint, with light weight, high strength, and good injured anastomosis site, could be able to shape easily. It is dry and comfortable, avoiding a gas-tight uncomfortable feeling, easy to remove, remodel, nurse, clean and disinfect after fixed. Patients also could film review directly with fixed splint.

Enrichment and separation of steroidal saponins from the fibrous roots of Ophiopogon japonicus using macroporous adsorption resins.

In this study, a simple and effective strategy for the enrichment of total steroidal saponins (TSS) from the fibrous roots of Ophiopogon japonicus (L. f.) Ker-Gawl. (FROJ) using macroporous adsorption resin was systematically developed. XAD-7HP resin was selected from six macroporous resins for further study because of the highest static adsorption and desorption capacities. The static adsorption of TSS on XAD-7HP resin fitted well to the Langmuir isotherm model and pseudo second-order kinetic model; the thermodynamics test showed that the adsorption process was spontaneous and exothermic. The dynamic tests on XAD-7HP resin columns demonstrated that the breakthrough volume was 16 bed volume (BV), and 6 BV of 80% ethanol was suitable for dynamic desorption. In a lab scale-up separation under optimal dynamic conditions, the content of TSS in the resin-enrichment fraction increased from 1.83% in the crude extracts to 13.86% by 7.59-fold with a recovery yield of 82.68%. Three steroidal saponins were obtained from the resin-enrichment fraction, and showed protective effects against oxidized low-density lipoprotein (ox-LDL) induced human umbilical vein endothelial cell (HUVEC) injury. Overall, these results suggested that XAD-7HP resin chromatography was an effective strategy for the large scale enrichment of TSS from FROJ, which showed the potential for functional food and pharmaceutical application.

[Study on an epilepsy EEG processing system based on independent component analysis (ICA)].

An epilepsy EEG processing system designed based on Independent Component Analysis (ICA) is introduced in the paper, in order to meet the requirements of epileptic screening in clinical medicine. The system adopts module structure and virtual instrument technology, its hardware is mainly configured in the signal-detecting box, data are exchanged between the box and the notebook computer or personal digital assistant (PDA) through certain digital interface, and ICA is executed in the notebook computer or PDA. The virtual EEG processing system based on ICA is able not only to perform ICA algorithms easily, but also to improve the developing efficiency greatly, and it is suitable for disease screening on a large scale.

[Design and application of a circuit for measuring frequency & duty cycle of stimulated bioelectrical signal].

Objective. To design a new type of circuit for measuring frequency & duty cycle of stimulated bioelectrical signal for the project of "the map of neuron-threshold in human brain and its clinical application". Method. This circuit was designed according to the character of stimulated bioelectrical signals. It was tested and improved and then used in the neuron-threshold stimulator. Result. The circuit was found to be very accurate for measuring frequency and the error for measuring duty cycle was below 0.2%. Conclusion. This circuit is well-designed, simple, easy to use, and can be applied in many systems.

[The method and implementation of measuring the peak of bioelectrical signals].

It is always very difficult to process the bioelectrical signals, sampling, amplifying and quantifying because of the different sources it comes from and the mechanism it depends on. This paper mainly introduces a method of measuring the peak value of bioelectrical signals, expatiates on the structure, testing result, analysis for error and measure taken for improvement of the circuit designed by this method. At last, the paper also points out that the method is wonderful, simple, easy to carry out, and can be used in many medical systems.

[The design of precision measure circuit for frequency & duty cycle of bioelectrical signal and its application in neuron-threshold stimulator].

This paper mainly introduces the principles of a type of circuit for measuring frequency & duty cycle of low-frequency signals, and its applications in neuron-threshold stimulator. The circuit has the advantages of simple structure and accurate measurement.