Hye-Jeong Song

Anti-glutamatergic effect of riluzole: comparison with valproic acid.

Riluzole, an anti-amyotrophic lateral sclerosis drug, known to decrease presynaptic glutamate release, is viewed as a candidate supplementary medication for epilepsy. In the present study, we compared the effects of riluzole and valproate (VPA) in the pilocarpine-induced limbic seizure model and in the gamma-hydroxybutyrate lactone (GBL)-induced absence seizure model. We applied immunohistochemical study for vesicular transporter 1 (VGLUT1) and extracellular recording in the rat dentate gyrus of both pilocarpine- and GBL-induced seizure models to measure effects of riluzole and VPA. Both VPA and riluzole treatments reduced VGLUT1 immunoreactivity. Riluzole treatment completely inhibited pre-ictal spikes and spike-wave discharges in the pilocarpine- and GBL-induced epilepsy models, whereas VPA partially inhibited these phenomena. In both seizure models, the anti-epileptic effects of VPA and riluzole are basically related to anti-glutamatergic (reducing field excitatory postsynaptic potential slope and excitability ratio), not GABAergic (paired-pulse inhibition) effect. Riluzole was more effective at reducing seizure activity in both epilepsy models than VPA. These results suggest that riluzole is a potential antiepileptic drug with activity against limbic seizure and absence seizure.

The protective effects of interleukin-18 and interferon-γ on neuronal damages in the rat hippocampus following status epilepticus.

To elucidate whether interleukin-18 (IL-18) or interferon-γ (IFN-γ) participates in neurodegeneartion, we investigated the changes in IL-18 and IFN-γ systems within the rat hippocampus following status epilepticus (SE). In non-SE induced animals, IL-18, IL-18 receptor α (IL-18Rα), IFN-γ and IFN-γ receptor α (IFN-γRα) immunoreactivity was not detected in the hippocampus. Following SE, IL-18 immunoreactivity was increased in CA1-3 pyramidal cells as well as dentate granule cells. IL-18 immunoreactivity was also up-regulated in astrocytes and microglia/macrophages. IL-18Rα immunoreactivity was detected in astrocytes and microglia/macrophages. IFN-γ immunoreactivity was detected only in astrocytes within all regions of the hippocampus. IFN-γRα immunoreactivity was increased in neurons as well as astrocytes. Intracerebroventricular infusions of recombinant rat IL-18 or IFN-γ alleviated SE-induced neuronal damages, while neutralization of IL-18, IFN-γ or their receptors aggravated them, as compared to saline-infused animals. These findings suggest that astroglial-mediated IFN-γ pathway in response to IL-18 induction may play an important role in alleviation of SE-induced neuronal damages.

Automatic detection of malaria parasite in blood images using two parameters

Malaria must be diagnosed quickly and accurately at the initial infection stage and treated early to cure it properly. The malaria diagnosis method using a microscope requires much labor and time of a skilled expert and the diagnosis results vary greatly between individual diagnosticians. Therefore, to be able to measure the malaria parasite infection quickly and accurately, studies have been conducted for automated classification techniques using various parameters. In this study, by measuring classification technique performance according to changes of two parameters, the parameter values were determined that best distinguish normal from plasmodium-infected red blood cells. To reduce the stain deviation of the acquired images, a principal component analysis (PCA) grayscale conversion method was used, and as parameters, we used a malaria infected area and a threshold value used in binarization. The parameter values with the best classification performance were determined by selecting the value (72) corresponding to the lowest error rate on the basis of cell threshold value 128 for the malaria threshold value for detecting plasmodium-infected red blood cells.

Looking for optimized weights of CA125 and HE4 in early screening system of ovarian cancer for Korean patients.

We try to find out the best weight values of CA125 and HE4 in a discriminant formula classifying ovarian cancer patients from benign patients. We utilize a logistic regression analysis for the early screening system of the ovarian cancer for Korean patients. We compare our system with ROMA (Risk of Ovarian Malignancy Algorithm) of Abbot corp. In view of AUC (Area under the ROC curve), sensitivity with 95% of specificity and accuracy are considered. We performed experiments based on the logistic regression analysis separated by the case of pre- and post- menopausal stages and by the stages of progression of cancer. In our experiments, we can increase about 15.6% points of sensitivity with 95% of specificity, compared to that of ROMA. In premenopausal cases, ROMA shows 93.32% of AUC value and our system shows 97.48% of AUC, 4.1% points higher than ROMA. AUC of the ROMA for premenopausal women was 93.32%, whereas the AUC of our system was 97.48%. Furthermore, the AUC of the ROMA for early-staged ovarian cancer was 91.35%, whereas the AUC of our system was 97.22%, showing that the diagnostic performance of our system was superior over that of the ROMA in Korean patient cases.

Buffer-less system for thermistor temperature measurement

This paper presents a temperature measurement system without the input buffer. A voltage follower or a buffer is required to minimize the influence of the ADC input impedance in the thermistor temperature measurement system. A high performance operational amplifier is usually required to prevent the noise and distortion due to the additional circuit. Negative power is also necessary to prevent the distortion of the low voltage input signal. This paper introduces a buffer-less system with a calibration method to resolve such problems. The low temperature coefficient precision resistors were employed to calibrate the input resistance and the leakage current of ADC. The experimental results show that the calibrated error decreased from 240mK to 30mK.

Construction of Korean Semantic Annotated Corpus

Semantic role labeling is to determine semantic relationships between a predicate and its arguments in a sentence. Although semantic annotated corpus should be necessary to do the labeling, unfortunately, Korean language is lack of the corpus data. In this paper, we construct Korean Proposition Bank (PropBank) corpus and Sejong case frame annotated corpus. Semantic annotation means a task which gives a semantic tag to an argument word in consideration of the dependency relationship between a predicate and the argument. And semantic annotated corpus is used in semantic role labeling based on machine learning methods. We annotate the syntactic annotated corpus built by Korea Electronics and Telecommunication Research Institute. We use frame files for Korean PropBank and Sejong case frame dictionary for Sejong case frame annotated corpus.

Internet-of-Things-based Electric Cell-substrate Impedance Sensing System

In this paper, we propose an electric cell-substrate impedance sensing system that can be accessed from the internet. The hardware specification was derived using numerical simulations and culture chamber impedance emulators, and the impedance calculation methods were compared. In addition, we propose server-type software to easily control and monitor the system from the internet. Experimental results show that it is advantageous to use an acquisition device of 50 mega samples per second or more and to calculate the impedance using a sine fitting method rather than the lock-in detection method that is generally used. During experiments, there was no problem accessing the proposed server from the outside with standard computing devices.

Hyperparameter tuning for hidden unit conditional random fields

Purpose In this paper, the problem of a nonlinear model – specifically the hidden unit conditional random fields (HUCRFs) model, which has binary stochastic hidden units between the data and the labels – exhibiting unstable performance depending on the hyperparameter under consideration. Design/methodology/approach There are three main optimization search methods for hyperparameter tuning: manual search, grid search and random search. This study shows that HUCRFs’ unstable performance depends on the hyperparameter values used and its performance is based on tuning that draws on grid and random searches. All experiments conducted used the n-gram features – specifically, unigram, bigram, and trigram. Findings Naturally, selecting a list of hyperparameter values based on a researchers’ experience to find a set in which the best performance is exhibited is better than finding it from a probability distribution. Realistically, however, it is impossible to calculate using the parameters in all combinations. The present research indicates that the random search method has a better performance compared with the grid search method while requiring shorter computation time and a reduced cost. Originality/value In this paper, the issues affecting the performance of HUCRF, a nonlinear model with performance that varies depending on the hyperparameters, but performs better than CRF, has been examined.

Fluorescence detection test by black printed circuit board based microfluidic channel for polymerase chain reaction

This paper proposes the optimal structure of a PCB-based micro PCR chip constructed on a PCB substrate using commercial adhesive tapes and plastic covers. The solder mask of the PCB substrate was coated black, and the area where the reaction chamber is attached was legend printed with white silk to minimize the noise during fluorescence detection. The performance of the PCR and fluorescence detection was compared using 6 types of reaction chambers, each made with different double-sided tapes. Three of the chambers were unsuccessful in completing the PCR. The performance of the other three chambers that successfully amplified DNA was compared using Taqman probe for Chlamydia Trachomatis DNA. The amplified product was illuminated diagonally with a blue LED to excite the product just before imaging, and the LED was turned off when the image was captured to prevent quenching of the probe. The images were taken 10 seconds prior to the last extension step for each cycle using a DSLR camera. The experiments were run as a quartet for each three chambers made with different double-sided tape. The results showed that there were significant difference between the three tapes.

Fluorescence reference plate for UV illumination using quantum dots

Many image acquisition methods of nucleic acids still depend on UV illumination, especially after the electrophoresis when determining the size of the target DNA. Therefore the quality of the UV illuminator in the gel documentation system, and the comparison of the fluorescence detected are crucial. This paper presents a fluorescence standard reference plate using quantum dots compared to the conventional method where an agarose gel containing ethidium bromide is loaded with standard samples. The fluorescence standard reference plate consists of chambers filled with commercially available quantum dots such as phosphor dots. The chamber is made by thermally attaching nylon and polyester, the former on the inside and the latter on the outside, for increased stability. The images of the proposed reference plate were captured more than 2 months in regular intervals. The intensity analysis of the images shows that the proposed reference plate delivers stable fluorescence over a long term period. The proposed reference plate can be utilized to compare the performance of various UV illuminators, or to set a standard fluorescence point for certain analyses.