Datian Ye

Synthesis and decomposition of transient-evoked otoacoustic emissions based on an active auditory model

In this paper, transient-evoked otoacoustic emissions (TEOAEs) are synthesized by an active auditory model, and decomposed by continuous wavelet transform (CWT) to study the frequency-latency relationship and the generation of TEOAE signals. The controlled voltage sources that relate to the mobile mechanism of the outer hair cells (OHCs) are proposed to serve as the generation sources of TEOAE signals. The state-variable method is adopted to calculate the auditory model. The mother wavelet used in CWT is selected on basis of the model. The results of this study show that the simulated TEOAE signal is similar to the clinically detected ones not only in the time-domain waveform, but also in the frequency-latency relationship. It seems to be clear that the generation of TEOAE signals is related to the same active mechanism as the cochlear sharp frequency selectivity.

Reference Values for Amplitude-Integrated EEGs in Infants From Preterm to 3.5 Months of Age

OBJECTIVES: Amplitude-integrated electroencephalogram (aEEG) is a valuable tool for the continuous evaluation of functional brain maturation in infants. The amplitudes of the upper and lower margins of aEEGs are postulated to change with maturation and correlate with postmenstrual age (PMA). In this study we aimed to establish reliable reference values of aEEG amplitudes, which provide quantitative guidelines for assessing brain maturation as indicated by aEEG results in neonates and young infants. METHODS: aEEGs from healthy infants (n = 274) with PMAs that ranged from 30 to 55 weeks were divided into 10 groups according to their PMAs. Two 5-minute segments were selected from each aEEG and were used to automatically calculate the upper and lower margins and bandwidths of the aEEG tracings. RESULTS: Interobserver agreement was achieved with an overall correlation of 0.99. The upper and lower margins of the aEEGs in both active and quiet sleep clearly rose in infants after the neonatal period. The bandwidth defined as the graphic distance decreased almost monotonically throughout the PMA range from 30 to 55 weeks. The lower margin of the aEEG was positively correlated with PMA, with a larger rank correlation coefficient during quiet sleep (r = 0.89) than during active sleep (r = 0.49). CONCLUSIONS: Reference values of aEEG amplitudes were obtained for infants with a wide range of PMAs and constituted the basis for the quantitative assessment of aEEG changes with maturation in neonates and young infants. The normative amplitudes of aEEG margins, especially of the lower margin in quiet sleep, are recommended as a source of reference data for the identification of potentially abnormal aEEG results.

Neurodevelopment in newborns: a sample entropy analysis of electroencephalogram.

The present paper investigates the neural ontogeny of newborns in view of electroencephalogram (EEG) complexity during active sleep (AS) and quiet sleep (QS). Sample entropy (SampEn) is applied to EEG recordings from 168 newborns with postmenstrual age (PMA) ranging from 25 to 60 weeks. The relationship between neurodevelopment and PMA is then explored according to the statistical analysis of the median and interquartile range of SampEn curves. It is found that SampEn of EEG during AS is higher than that during QS. SampEn increases during both AS and QS before about 42 weeks in PMA while it ceases its increase in QS and even decreases in AS after newborns reaching term age. A distinct decrease in the interquartile range of SampEn is found with increasing PMA (from 25 to about 50 weeks), followed by maintenance of low fluctuation in SampEn curves. The study in this paper sets the stage for exhaustive investigation of the SampEn of EEG during brain maturation in newborns. And it could be hoped that SampEn in sleep EEG might be a useful parameter against which delays and aberrations in brain maturation might be tested. The SampEn changes during brain maturation also offer functional clues about neurodevelopment, based on which further explorations could be done. The significance of this paper is the discovery of the decrease in EEG complexity after newborns reaching term. Although some potential neurophysiologic reasons are given, this new discovery might require more study to investigate. In addition, the fluctuation of EEG complexity is analyzed for the first time, which helps to understand the EEG maturation in neurodevelopment.

Automatic Segmenting and Classifying the Neural Stem Cells in Adherent Culturing Condition

The neural stem cells (NSCs) have a wide range of perspectives in clinical applications for neurology disorders due to their multi-potent potentials of differentiation. Automatic segment and classify the NSCs can be useful tools for biologist to monitor the progress of differentiation. In this paper, a hybrid image segmentation framework based on self-organizing map and watershed algorithm was applied to segment the NSCs in adherent culturing conditions. The cells shapes were analyzed using Fourier descriptors and classified using a feed-forward neural network. The results indicated that different shapes of NSCs in adherent culturing condition can be successfully segmented and classified based on these methods.

A Method for Widening the Range of Force Measurement and Gap Adjustment in the Total Knee Replacement

The artificial knee replacement (TKR) surgery is one of the major surgeries to cure the severe pathological changes in the knee for osteoarthritis. The soft tissue balance is very important to prolong the artificial joints life in the TKR, the authors have developed a soft tissue balance measurement system to meet the quantitative soft tissues balance measurement requirement in the TKR. In the system applications, we found that the system can not fully satisfy the range of the soft tissues force measurement and gap adjustment. In this paper, we proposed a method to widen the range of the force measurement based on the level principle, and gap adjustment by combining the adjustable mechanical structure with fixed thickness block. And by designing some different shapes of touch plate, the system can measure the soft tissues force generated in the different parts round the knee. The preliminary test shows that the measurement system can evidently improve the force measurement range and the gap adjustment range in the knee joint, and largely reducing the designing the difficulty of the mechanical machining.

A method for dynamically measuring the Soft Tissue Balance in the Total Knee Replacement

Osteoarthritis is one of the most common arthropathy in the world, and the artificial knee replacement surgery becomes one of the major measures to cure the severe pathological changes in the knee. The soft tissue balance is very important to prolong the artificial joint’s life in the total knee replacement (TKR), but now the balance is mainly depended on the surgeon’s experience, so the result is not confident. In order to meet the quantitative soft tissues balance measurement requirement in the TKR, a new soft tissues balance measurement method and system have been developed based on the load sensor technology, computer graphics technology and the precise mechanical design in this paper. In the system, six precise load sensors have been embedded in the front end measure device, which will be inserted into the knee joint. Each sensor is responsive to a force generated between the condyle and the device, and the pressure of the sensors represents the force of the posterior, middle, and anterior position in the medial/lateral part of the knee joint. Furthermore, the device has the function that can change the distance between its upper and lower plate by the mechanical structure for adjusting the space in the knee joint. The preliminary test shows that the measurement system can accomplish the force measurement and the distance adjustment in the knee joint, and display the data of the force distribution in three-dimensional manner in real-time. Otherwise, all the reliable force and distance data during measuring saved can be provided for the modeling of the knee joint dynamics.

Localization of hearing loss on the basis of transient-evoked otoacoustic emissions by using wavelet transform

Otoacoustic Emissions are of clinical interest due to their relationship with the function of the peripheral auditory system. In this paper, a procedure is proposed for localizing the hearing loss region on the basis of clinically detected transient-evoked otoacoustic emissions (TEOAE). The continuous wavelet transform is utilized to decompose the TEOAE, and the root mean square of each wavelet scale is treated as the quantitative criterion for the localization. The results obtained by this method agree reasonably well with those by audiogram and DPGRAM. The work described provides a clinically useful method for the analysis of TEOAEs.

Managing dynamic medical data in a distributed mode

In telemedicine applications, it is necessary to archive and query some dynamic data of remote objects. Because the data is dynamic and usually of a huge amount, if we use the market available database server directly, it is difficult to archive dynamic data, and the huge amount of data makes communication very crowded. To solve this problem, we present a distributed management method which uses file servers and database servers to manage data objects and database tables respectively, and connect them with links in the records of the tables. Based on this mode, we design an archiving application running on the file server to archive dynamic data. After the dynamic data are archived, they can be queried as static data. To search a data object, an application queries the database server for contents of the data objects, and gets the link of the data object, then the application gets the data object from file server. For other applications, a transforming application protocol to support access of database in HL7 protocol has been designed. The results indicate that the proposed mode can simplify data management and improve communication condition.

Wavelet analysis of TEOAE simulated by a homomorphic auditory model

Otoacoustic Emissions (OAE) detected in the ear canal are acoustic waves produced by the cochlea. In this paper, Continuous Wavelet Transform (CWT) is adapted to analyze Transient Evoked Otoacoustic Emission (TEOAE), one of the important kinds of OAE. The TEOAE signal is simulated by an homomorphic auditory model, in which controlled voltage sources are regarded as the generation sources of OAE. In order to get more information about TEOAE from its wavelet analyzed result, the scale number and the mother wavelet are chosen based on this model. In this paper, special attention is also paid to the localization of the abnormal regions in the cochlea. The results given in the paper show that the abnormal regions can be located from the wavelet analyzed result.

Electrowetting of the blood droplet on the hydrophobic film of the EWOD chips

Electrowetting-on-dielectric (EWOD) is a new method for handling droplets on the microfluidic chips. A most promising application for EWOD chips is the clinical diagnostics on human physiological fluids. This paper uses pure blood of rabbit as the experimental sample to test the wettability of the fluorocarbon polymer (p-C:F) hydrophobic layer of the EWOD chips. The contact angle variation of the blood droplet is observed, which provides the possibility of pure blood driven on the chips of p-C:F film. Forty multiple magnification images of the blood droplet are acquired by delicate experiments and the contact angles are calculated based on image processing technology. The electrowetting of the blood droplets on the EWOD chips is analyzed and the experimental results are in good agreement with the theoretical calculation