1.A two dimensional stress analysis of fixed prosthesis with rigid or nonrigid connectors.
Heung Seo YANG ; Van P THOMPSON
The Journal of Korean Academy of Prosthodontics 1992;30(3):445-456
No abstract available.
Prostheses and Implants*
4.A two-dimensional video based quantification method and clinical application research of motion disorders.
Yubo SUN ; Peipei LIU ; Yuchen YANG ; Yang YU ; Huan YU ; Xiaoyi SUN ; Jialing WU ; Jianda HAN ; Ningbo YU
Journal of Biomedical Engineering 2023;40(3):499-507
The increasing prevalence of the aging population, and inadequate and uneven distribution of medical resources, have led to a growing demand for telemedicine services. Gait disturbance is a primary symptom of neurological disorders such as Parkinson's disease (PD). This study proposed a novel approach for the quantitative assessment and analysis of gait disturbance from two-dimensional (2D) videos captured using smartphones. The approach used a convolutional pose machine to extract human body joints and a gait phase segmentation algorithm based on node motion characteristics to identify the gait phase. Moreover, it extracted features of the upper and lower limbs. A height ratio-based spatial feature extraction method was proposed that effectively captures spatial information. The proposed method underwent validation via error analysis, correction compensation, and accuracy verification using the motion capture system. Specifically, the proposed method achieved an extracted step length error of less than 3 cm. The proposed method underwent clinical validation, recruiting 64 patients with Parkinson's disease and 46 healthy controls of the same age group. Various gait indicators were statistically analyzed using three classic classification methods, with the random forest method achieving a classification accuracy of 91%. This method provides an objective, convenient, and intelligent solution for telemedicine focused on movement disorders in neurological diseases.
Humans
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Aged
;
Parkinson Disease/diagnosis*
;
Aging
;
Algorithms
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Gait
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Lower Extremity
5.A Case of Successful Treatment of Cervical Pregnancy with Methotrexate and Leucovorin.
Kang Joo BAEK ; Dong Ryool LIM ; P S PACK ; Koe Seung YANG ; Ho Soon JUNG
Korean Journal of Perinatology 1997;8(1):70-78
Until recently, the cervical pregnancy have been treated with surgery, usually hy- sterectomy, because of uncontrollable heavy vaginal bleeding. The development of sophisticated ultrasound which allows early diagnosis of cervical pregnancy and methotrexate chemotherapy opened up new therapeutic options in the management of this unusual but potentially life threatening complication of pregnancy which have been always a nightrnare for the gynecologist. We are reporting a case of cervical pregnancy diagnosed in 12 weeks of gestation. The patient was successfully treated with alternative administration of methotrexate (1 mg/kg, intramuscularly) and leucovorin (0.1 mg/kg, intramuscularly) without surgical intervention, in order to preserve both the uterus and fertility. Follow up was done with serum beta hCG and pelvic ultrasonography. Complete resolution of the cervical pregnancy was obtained at 50 days after starting methotrexate treatment. This case gave us the opportunity to review the recent literature on cervical pregnancy.
Drug Therapy
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Early Diagnosis
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Fertility
;
Follow-Up Studies
;
Humans
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Leucovorin*
;
Methotrexate*
;
Pregnancy*
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Ultrasonography
;
Uterine Hemorrhage
;
Uterus
6.Distribution of HLA-B allele polymorphism of 8962 Han population in Liaoning of China.
Chinese Journal of Medical Genetics 2006;23(4):461-462
<p>OBJECTIVETo investigate the distribution of genetic polymorphism of HLA-B locus in Liaoning Han population.p><p>METHODSThe technique of polymerase chain reaction-sequence specific primers (PCR-SSP) was adopted in genotyping a sample of 8962 unrelated healthy individuals collected from a Chinese Han population in Liaoning area. The allele frequency of HLA-B was calculated and was compared with the results from other population.p><p>RESULTSThirty-four HLA-B alleles were detected. The more common HLA-B allele included B*15(14.42%), B*40(14.33%) and B*13(11.99%). The B*82 and B*83 were absent. Forty-nine HLA-B antigens were detected.p><p>CONCLUSIONThe HLA-B allele polymorphism distribution of Liaoning Han population exhibits its own characteristic and the difference from old south and north Han population in China.p>
Alleles
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Asian Continental Ancestry Group
;
genetics
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China
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Gene Frequency
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Genotype
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HLA-B Antigens
;
genetics
;
Humans
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Polymerase Chain Reaction
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Polymorphism, Genetic
;
genetics
7.Evaluation of imaging performance of major image guidance systems
Chan MF* ; Yang J ; Song Y ; Burman C ; Chan P ; Li S
Biomedical Imaging and Intervention Journal 2011;7(2):1-7
Purpose: The imaging characteristics of two popular kV cone-beam CT (CBCT) and two MVCT systems utilised in
image-guided radiation therapy (IGRT) were evaluated.
Materials and methods: The study was performed on Varian Clinac iX, Elekta Synergy S, Siemens Oncor, and
Tomotherapy. A CT phantom (Catphan-504, Phantom Laboratory, Salem, NY) was scanned for measurements of image
quality including image noise, uniformity, density accuracy, spatial resolution, contrast linearity, and contrast resolution.
The measurement results were analysed using in-house image analysis software. Reproducibility, position correction,
and geometric accuracy were also evaluated with markers in a smaller alignment phantom. The performance evaluation
compared volumetric image properties from these four systems with those from a conventional diagnostic CT (CCT).
Results: It was shown that the linearity of the two kV CBCT was fairly consistent with CCT. The Elekta CBCT
with half-circle 27-cm FOV had higher CT numbers than the other three systems. The image noises of the Elekta kV
CBCT, Siemens MV CBCT, and Tomotherapy fan-beam CT (FBCT) are about 2-4 times higher than that of the Varian
CBCT. The spatial resolutions of two kV CBCTs and two MV CBCTs were 8-11 lp/cm and 3-5 lp/cm, respectively.
Conclusion: Elekta CBCT provided a faster image reconstruction and low dose per scan for half-circle scanning.
Varian CBCT had relatively lower image noise. Tomotherapy FBCT had the best uniformity.
8.Stress and hippocampus.
Journal of Forensic Medicine 2002;18(1):48-51
This review summarizes the present advance of effects of stress on hippocampal structure and function and the role of hippocampus in feedback regulation of thalamic-pituitary-adrenocortical (HPA) axis during stress. It shows that stress can affect hippocampal structure and function, on the other hand, the hippocampus can also suppress the stress reaction through the feedback regulation of HPA axis, but chronic stress can attenuate this regulation, then significantly impair its structure and function.
Animals
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Hippocampus/physiopathology*
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Humans
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Hypothalamo-Hypophyseal System/physiology*
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Pituitary-Adrenal System/physiology*
;
Stress, Physiological/physiopathology*
9.Research progress on attention level evaluation based on electroencephalogram signals.
Journal of Biomedical Engineering 2023;40(4):820-828
Attention level evaluation refers to the evaluation of people's attention level through observation or experimental testing, and its research results have great application value in education and teaching, intelligent driving, medical health and other fields. With its objective reliability and security, electroencephalogram signals have become one of the most important technical means to analyze and express attention level. At present, there is little review literature that comprehensively summarize the application of electroencephalogram signals in the field of attention evaluation. To this end, this paper first summarizes the research progress on attention evaluation; then the important methods for electroencephalogram attention evaluation are analyzed, including data preprocessing, feature extraction and selection, attention evaluation methods, etc.; finally, the shortcomings of the current development in the field of electroencephalogram attention evaluation are discussed, and the future development trend is prospected, to provide research references for researchers in related fields.
Humans
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Reproducibility of Results
;
Electroencephalography
10.Research on eye movement data classification using support vector machine with improved whale optimization algorithm.
Yinhong SHEN ; Chang ZHANG ; Lin YANG ; Yuanyuan LI ; Xiujuan ZHENG
Journal of Biomedical Engineering 2023;40(2):335-342
When performing eye movement pattern classification for different tasks, support vector machines are greatly affected by parameters. To address this problem, we propose an algorithm based on the improved whale algorithm to optimize support vector machines to enhance the performance of eye movement data classification. According to the characteristics of eye movement data, this study first extracts 57 features related to fixation and saccade, then uses the ReliefF algorithm for feature selection. To address the problems of low convergence accuracy and easy falling into local minima of the whale algorithm, we introduce inertia weights to balance local search and global search to accelerate the convergence speed of the algorithm and also use the differential variation strategy to increase individual diversity to jump out of local optimum. In this paper, experiments are conducted on eight test functions, and the results show that the improved whale algorithm has the best convergence accuracy and convergence speed. Finally, this paper applies the optimized support vector machine model of the improved whale algorithm to the task of classifying eye movement data in autism, and the experimental results on the public dataset show that the accuracy of the eye movement data classification of this paper is greatly improved compared with that of the traditional support vector machine method. Compared with the standard whale algorithm and other optimization algorithms, the optimized model proposed in this paper has higher recognition accuracy and provides a new idea and method for eye movement pattern recognition. In the future, eye movement data can be obtained by combining it with eye trackers to assist in medical diagnosis.
Animals
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Support Vector Machine
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Whales
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Eye Movements
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Algorithms