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Biomedical subjects

B S Choi

Publications and source records attributed to B S Choi.

49 records · Page 3Linked to original sources
PubMed1989

A study on continuous follow-the-leader (FTL) gaits: an effective walking algorithm over rough terrain.

The follow-the-leader (FTL) gait is an effective walking algorithm for a legged system to traverse a rough terrain. In an FTL gait, all the legs simply place at the footprints made by the legs ahead of them. By this way the demand on foothold selection is significantly reduced. A special category of FTL gaits, called continuous FTL gaits, provide a smooth body motion during walking and enable the legged system to reach a higher speed. In this paper, a comprehensive study of continuous FTL gaits is presented. The equations for two types of continuous FTL gaits are formulated. The stability of these continuous FTL gaits is studied analytically and verified numerically. Strategies of forbidden area avoidance and special methods of large foot adjustment are introduced. The motion resulting from the use of these strategies and methods is simulated and checked using computer graphics.

Algorithms↗
PubMed1988

Physiological and 15N-NMR analysis of molecular nitrogen fixation by Methanococcus thermolithotrophicus, Methanobacterium bryantii and Methanospirillum hungatei.

Two mesophilic methanogenic bacteria, Methanobacterium bryantii strain MOH and Methanospirillum hungatei strain GP1 were demonstrated, using several different experimental approaches, to fix dinitrogen. Evidence includes (1) growth with N2 as the sole nitrogen source; (2) incorporation of 15N2 into cellular material (both soluble amino acid pools and insoluble cell protein and other macromolecules) detected by 15N-NMR spectroscopy; (3) acetylene reduction to ethylene by the cells, and inhibition of this reaction by bromoethanesulfonic acid (BES), a methanogen inhibitor. High-resolution 15N-NMR analysis of ethanol extracts of these organisms and cross-polarization magic-angle sample spinning analysis of the solid debris from these extracts are compared to labeled material from Methanococcus thermolithotrophicus, a methanogen previously determined to fix dinitrogen.

Clostridium↗
PubMed1987

15N-NMR studies of Methanobacterium thermoautotrophicum: comparison of assimilation of different nitrogen sources.

Methanobacterium thermoautotrophicum can utilize glutamine and urea as well as ammonia as the sole nitrogen source during growth on H2 and CO2. High-field 15N-NMR has been used to compare the assimilation of these different nitrogen sources by this organism. The 15N-NMR spectra of extracts of cells grown in media containing [delta-15N]glutamine as the nitrogen source show that the glutamine amide nitrogen is rapidly converted to glutamate. The 15N-NMR spectra of cell extracts from cells grown on [15N]urea show a marked increase in the labeling of the alpha-NH2 of glutamate concurrent with a decrease in the urea resonance. These two nitrogen sources do not show the metabolic shift to alanine as the major resonance in stationary phase as is seen with 15NH4Cl. This behavior is discussed in terms of the enzymes of nitrogen metabolism.

Amino Acids↗
PubMed1986

NMR study of isoleucine transfer RNA from Thermus thermophilus.

An NMR and nuclear Overhauser effect (NOE) analysis of Thermus thermophilus tRNAIle1a is presented. This species contains modifications including s2T54 and s4U8 [Horie, N., Hara-Yokoyama, M., Yokoyama, S., Watanabe, K., Kuchino, Y., Nishimura, S., & Miyazawa, T. (1985) Biochemistry 24, 5711-5715]. All the expected secondary and reverse Hoogsteen AU pairs were identified, with one possible exception. The general geometry of the T psi C loop is the same as the Escherichia coli species, and there is NOE evidence for an A9-UA12 triple. Preliminary measurements of solvent exchange rates of internally hydrogen-bonded bases suggest that this tRNA is more stable than previously studied E. coli and yeast tRNAs.

Base Sequence↗
PubMed1985

Nuclear magnetic resonance observation of the triple interaction between A9 and AU12 in yeast tRNAPhe.

The nuclear Overhauser effect (NOE) was used to identify one of the amino proton resonances of base A23 in interaction with A9. These bases form a triple with U12 in the D stem of yeast tRNAPhe. The identification was verified by finding an NOE from this amino proton to the C8 proton of A9, as determined by comparisons of NOE's in a native and a C8-deuterated sample.

Magnetic Resonance Spectroscopy↗
PubMed1978

The air meniscus sign in sclerosing hemangioma of the lung.

The air meniscus sign occurs in a number of lung conditions, including infection, benign and malignant tumors, and hematoma. Sclerosing hemangioma does not appear to have been implicated previously in this connection. Two such cases are described. Possible mechanisms of air meniscus formation and its diagnostic value in sclerosing hemangioma are discussed.

Adult↗
PubMedDate not supplied

[A study for enhancing the image of medical services in a hospital].

The purpose of this study was to investigate client's satisfaction and to promote the image of medical services in the hospital. It is important to identify how client is satisfy with the medical services for the image of hospital. The study was done on population group of 334 patients and their families who had been admitted to the hospital in Seoul from July 15 to July 31, 1995. Data was collected by questionnaires on all steps of the research. Subjects were instructed to rate the 5 point likert type scale on items. 328 questionnaires returned and were used for this analysis. The results were summarised as follows: 1. The characteristics of the subjects were as follows: the age group of 20-39 years was 61.0%. For academic background, 51.2% were graduated from high school and 28.7% were graduated from College. 2. The average scores for the services rendered were as follows: a) Satisfaction on nursing services 3.75 b) Satisfaction on kindness of hospital workers 3.55 c) Satisfaction on medical services 3.36 d) Satisfaction on environmental elements 3.19 e) Satisfaction on diet for the patients 3.18 3. The lowest score of client's satisfaction on each area shown in this study is as follows: a) Doctors explain result of tests and patient's home management 3.23 b) Nurses are eager to resolve client's problem 3.47 c) In environmental elements, toilets, room temperature, diet, store 2.81-2.91.

Adult↗