Showing papers by "Korea University published in 1986"

The current pathobiology and chemotherapy of clonorchiasis

Abstract: This special issue is devoted to a review of the current state of knowledge of clonorchiasis. Sections deal with: the biology of Clonorchis sinensis; geographical distribution, with particular regard to Korea; epidemiology; pathogenesis; clinical features; diagnosis; prevention and control; chemotherapy.

Limits to nu micro, nu e--> nu tau oscillations and nu micro, nu e--> tau - direct coupling.

Abstract: We have located 3886 neutrino interactions in the fiducial volume of a hybrid emulsion spectrometer installed in the Fermilab wide-band neutrino beam. A search for tau/sup -/ decays yielded no candidate, resulting in an upper limit of 0.002 (0.073) for direct coupling of ..nu../sub ..mu../ (..nu../sub e/) to tau/sup -/. The ..nu../sub ..mu../ (..nu../sub e/) to ..nu../sub tau/ limits to mass differences and mixing angles (..cap alpha..) between the neutrinos are at maximum mixing ..delta..M/sup 2/<0.9 (9.0) ev/sup 2/, and at maximum sensitivity sin/sup 2/(2..cap alpha..)<0.004 (0.12). The direct-coupling limits are also used to show that most tau/sup -/ decays must contain a neutral lepton other than ..nu../sub ..mu../ or ..nu../sub e/.

Thermotropic Main Chain Polyesters with Polymethylene Spacers and Their Low Molecular Weight Model Compounds—Odd-Even Effect of Polymethylene Spacers

Abstract: A series of main-chain thermotropic polyesters which have an alternating sequence of mesogenic units and polymethylene spacers as well as their model compounds with two terminal mesogenic units and central spacers were prepared. Their liquid crystalline behavior, especially their thermal transition properties and nature of mesophases were compared with each other. The polymers and the low molecular weight model compounds exhibited in their transition temperatures distinctive odd-even dependence on the number of methylene units in the spacer. All of them formed nematic mesophases in melts. The liquid crystalline properties of the polymers and the model compounds were studied by differential scanning calorimetry and on the hot-stage of a polarizing microscope.

Lifetimes of the charmed particles D+/-, F+/-, and Lambda c+ produced by neutrinos.

Abstract: We report final results for the D/sup + -/, F/sup + -/, and ..lambda../sub c//sup +/ lifetimes measured with a hybrid emulsion spectrometer in the wide-band neutrino beam at Fermilab. In total, 3886 neutrino and antineutrino interactions were located in the fiducial volume of the emulsion. From these interactions we have unambiguously identified 6 F/sup + -/ and 13 ..lambda../sub c//sup +/ decays, for which the fitted lifetimes are tau(F/sup + -/) = (2.6/sub -0.9//sup +1.6/) x 10/sup -13/ s and tau(..lambda../sub c//sup +/) = (2.0/sub -0.5//sup +0./ 7) x 10/sup -13/ s. 28 other decays are consistent with a D/sup +/ or D/sup -/ hypothesis. From these events, we obtain a D/sup + -/ lifetime of (11.1/sub -2.9//sup +4.4/) x 10/sup -13/ s.

Clinical significance of unilateral sinusitis.

Abstract: In general, the etiologic factors of chronic paranasal sinusitis are systemic conditions such as nutrition, predisposition, allergy, and local factors such as nasal anatomic conditions. Among these factors, the development of unilateral sinusitis is a model case verifying the influence of local factors. In my study of 640 cases over a certain period of time, a comparison was made between 161 cases of unilateral sinusitis and 479 cases of bilateral sinusitis in order to verify the effects of local factors in the development of this disease. Patients with a history of previous sinus surgery or tumors were eliminated from the cases. 1. The male-female incidence rate, and the age distribution of the patients at the initial visit showed no prominent differences between unilateral and bilateral cases. 2. It was found that a larger number of cases of unilateral sinusitis had a duration of less than one year as compared to bilateral sinusitis which were longer than and year. Therefore it can be said that the duration of unilateral sinusitis is usually shorter than that of bilateral sinusitis. 3. In unilateral cases the patients with moderate to severe nasal septal deviation, one number of patients with septal deviation towards the diseased side was twice as high as that on the non-affected side. 4. The incidence rate of polyps occurring in the middle meatus was shown to be about twice as high in bilateral cases as in unilateral cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Profiles of Serum Bile Acids in Liver Diseases

Abstract: Cholylglycine (CG) and sulfolithocholylglycine (SLCG) in fasting and postprandial serum were determined in patients with liver diseases by radioimmunoassay. In normal controls, fasting CG and SLCG were 54.67±68.66ng/100ml and 16.61 ±12.84ng/100ml respectively, while postprandial CG and SLCG were 61.21 ±37.29ng/100ml and 21.95± 15.9ng/100ml respectively. In liver disease, serum bile acids were elevated. The greatest increase was found in acute viral hepatitis but moderate or slight increase was also found in chronic active hepatitis, liver cirrhosis, and hepatoma. Fasting bile acids seem to be a sensitive index for hepatocellular dysfunction but not for differential diagnosis of liver diseases. In liver diseases except hepatoma, fasting CG and SLCG correlated significantly with total bilirubin, albumin, GOT, GPT, and alkaline phosphatase but not with cholesterol. Insignificant elevation of bile acids was found postprandially in patients with liver diseases as well as normal controls and postprandial bile acids were not more sensitive than fasting ones.

Lifetime of D0 charmed mesons produced in neutrino interactions.

Abstract: We report final results for the ${D}^{0}$ lifetime measured with a hybrid emulsion spectrometer in the wide-band neutrino beam at Fermilab. In a total of 3886 neutrino and antineutrino interactions located in the emulsion fiducial volume, we have found 58 ${D}^{0}$ decays, from which we determine the lifetime to be (${4.3}_{\ensuremath{-}0.5\ensuremath{-}0.2}^{+0.7+0.1}$) \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}13}$ s.

Application of adaptive control to a nuclear power plant

Abstract: Possible applications of an adaptive control method to a pressurized water reactor nuclear power plant are investigated. A self-tuning control algorithm with the generalized minimum variance strate...

Acetylation of blasticidin S by its producing actinomycetes.

Abstract: A blasticidin S-producing actinomycetes, Streptoverticillium sp. JCM 4673 possesses an enzyme activity which acetylates the drug in the presence of acetyl coenzyme A. The modified drug was biologically inactive when tested against protein synthesis in vivo and in vitro. Production of the enzyme which acetylates blasticidin S increases with formation of the antibiotic during cell growth.

Variability in Sensitivity to Polyoxin B of Isolates of Alternaria mali and Decreased Fitness of Polyoxin resistant Isolates

Abstract: The 540 monoconidial isolates of Altemaria mali were obtained in 1983 from apple orchards at Seoul, Suweon, Cheongju, Kochang, Daegu, and Jinju in Korea. The sensitivity of A. mali to polyoxin B greatly varied among isolates and locations. Most of isolates were sensitive to polyoxin B, but 11 isolates showed a high level of resistance, particularly from Kochang and Daegu where polyoxin B had been applied frequently. Conidial germination and mycelial growth of resistant isolates were not inhibited at higher concentrations of polyoxin B compared to the sensitive ones. The polyoxin-resistant isolates were not resistant to the fungicides iprodione and polydong and showed a reduced activity for conidial formation and mycelial growth. The isolates of A. mali with resistance to polyoxin B appear to have decreased fitness in nature. Zusammenfassung Variabilitat der Empfindlichkeit der Alternaria mali Isolaten gegenuber Polyoxin B und verminderte Fitness der Polyoxin-resistenten Isolaten Die 540 Einzelsporisolate von Alternaria mali wurden aus Apfelgarten in Seoul, Suweon, Cheongju, Kochang, Daegu und Jinju, Korea, im Jahr 1983 gewonnen. Die Empfindlichkeit von A. mali gegenuber Polyoxin B war zwischen den Isolaten von verschiedenen Standorten sehr unterschiedlich. Die meisten der gepruften Isolate waren gegen Polyoxin B empfindlich, aber 11 Isolate aus Kochang und Daegu, wo Polyoxin B haufig gespritzt worden war, zeigten ein hohes Resistenzniveau. Im Vergleich mit den empfindlichen Isolaten werden Konidienkeimung und Myzelwachstum der resistenten Isolate durch hohere Konzentration des Polyoxin B nicht gehemmt. Die Polyoxinresistenten Isolate waren gegen die Fungizide Iprodion und Polydong nicht resistent und zeigten eine verminderte Konidienbildung und schwacheres Myzelwachstum. Die Isolate von A. mali mit Polyoxin B-Resistenz scheinen im Freiland eine verminderte Fitness zu haben.

Self-tuning control application to a nuclear power plant

Abstract: The aim of this paper is to investigate the application possibilities of a self-tuning control method to a pressurized-water reactor (PWR) nuclear power plant. A self-tuning control algorithm which incorporates pole assignment into the generalized minimum variance strategy with a particular form of cost function is employed. This algorithm enables closed-loop system stability characteristics to be readily specified and facilitates reference following. The control system design is based on a second-order linear model with unknown, time-varying parameters. To ensure that this low-order model describes the complex real dynamics well enough for control purposes, control parameters are updated on-line with a recursive estimation sequences of the extended least-squares method. Weighting polynomials are also adjusted on-line to keep closed-loop poles at the desired location and to satisfy the zero steady-state condition and disturbance rejection. The purpose of this control system is to hold the average coolant ...

Self-Biased Silicon Detectors with a Built-In Field for Measuring Heavy Charged Particles

Abstract: Self-biased silicon detectors with a good carrier collection and a high speed response have been produced by using a wafer with high resistive epitaxial layer grown on a low resistive silicon substrate and also a wafer with the graded impurity distribution formed diffusion technique. The build-in field induced by a large difference of impurity concentration is expected to be effective for sweeping away the high density charge plasma to electrodes before recombination. Energy spectra of fission fragments from /sup 252/C/sub F/ are measured by using the detectors. The results show that the detector will be promising for measurement of heavy charged particles.

Growth experiment of Hantaan virus in A549 cells: an attempt to improve the immunofluorescent antibody technique for hemorrhagic fever with renal syndrome.

Abstract: An assay method for the infectivity of Hantaan virus, a causative agent of HFRS (hemorrhagic fever with renal syndrome), was developed by the use of IFA (immunofluorescent antibody technique). With the aid of this method, the growth characteristics of Hantaan virus, 76-118 strain, were followed in A549 cells. At a maximal MOI (multiplicity of infection) of 1.6 VAIU (viral antigen-inducing units) per cell, the conventionally available value, plateau level potencies of the viral antigen and virus infectivity were attained at eight and ten days postinfection, respectively, and most of the infective virus produced accumulated in the culture fluids of infected cells. When infections were defined with MOI values in terms of VAIU per cell, development of the viral antigen was highly consistent and followed a given pattern of kinetics. Based on these findings, a protocol for preparation of the viral antigen in IFA was presented, wherein spot culture and FBS treatment were emphasized as effective procedures to minimize non-specific staining.

Differentiation of Physiologic Races of the Rice Blast Fungus, Pyricularia oryzae Cav. by PAGE‐electrophoresis

Abstract: Eighty-three isolates of the rice blast fungus (Pyricularia oryzae) were tested with respect to genetic diversity and the possibility of race differentiation by electrophoresis. The fungus was genetically very heterogeneous. The isolates were differentiated into 6 races by pathogenicity on race differential varieties. There was little correlation between pathogenicity and zymogram types of one particular enzyme such as esterase, phosphatase or catalase. The isolates were divided into 14 groups by the combination of the zymogram types of the three enzymes. The isolates in the same group showed similar pathogenicity. A new method is proposed which differentiates the blast fungus races by the combination of zymogram type of enzymes. The details, are discussed.

Analysis of microdefects in a silicon single crystal by diffuse X-ray scattering using synchrotron radiation

Abstract: Oxide precipitates (platelets in {100}) in Cz silicon single crystals induced by heat treatment at 750°C for 100 h and for 33 h have been investigated by diffuse X-ray scattering (Huang scattering). High angular resolution measurements of diffuse scattering have been carried out near the 400 reciprocal lattice point using a triple-crystal diffractometer in a parallel ( n , − n , n ) setting. Diffuse X-ray scattering from oxide precipitates of several hundred angstroms in size has been observed. The experimental results have been compared with the calculation based on the Huang scattering theory.

First and second sound in He films.

Abstract: In consideration of a collision integral in the Boltzmann equation and with use of kinetic and hydrodynamical equations, the velocities of the first and second sound in liquid /sup 4/He films are evaluated as functions of temperature, and the attenuation coefficients are obtained. The second sound is 2/sup -1/2/ times the first-sound velocity in the low-temperature and low-frequency limit.

The Stress Exercise Test and Oxygen Uptake in Normal Korean Men

Abstract: In order to observe physiologic responses to exercise and measure the normal value of maximal oxygen uptake, an exercise stress test, using a bicycle ergometer, was carried out on 82 normal males, 20 to 60 years of age. The exercise test consisted of 1 minute of unloaded cycling with an increment of 25 watts each minute to the point of exhaustion. Oxygen uptake, anaerobic threshold(AT), minute ventilation, and CO2 output were measured with an automatic gas analyzer and a pneumotachograph during the exercise. The results are summarized as follows: The maximal oxygen uptake in the 20–29 year-old group of subjects was 39.6ml/min/kg, and it decreased with advancing age. The anaerobic threshold was 1.22–1.5 L/min in all age groups. No significant differences by age were observed. The mean ratio of the anaerobic threshold to the maximal oxygen uptake was 57%. The minute ventilation at maximal exercise was 65% of the maximal voluntary ventilation. This means that the subject cannot perform exercise at all, because of shortness of breath, that some potentially useful ventilation is left. Keywords: Oxygen uptake, Anaerobic threshold, Minute ventilation INTRODUCTION It has been reported in some epidemiologic studies1,2) that an increase in physical activity reduces the incidence of hypertension and coronary mortality, and affects lipid and carbohydrate metabolism in a favorable way. In the present study, an effort was made to investigate physiologic responses to exercise and determine the normal values of maximal oxygen uptake in Korean subjects for objective measures of physical fitness. When a person is subjected to progressively increasing work loads, there is a linear relation between work load and oxygen uptake until a plateau is reached, and, thereafter, despite the increasingly heavier work load, the oxygen uptake levels off or even declines. This turning point of oxygen uptake is known as maximal oxygen uptake. The maximal oxygen uptake is widely used as a useful tool for the evaluation of the functional capacity of the cardiovascular system to deliver oxygen to the tissues of the human body which has normal pulmonary function.3,4) As the work load is increased, the oxgen requirement of the exercising muscles increases. However, after a certain increment in the work load, the oxygen transported to the muscle cannot meet the requirement. In this situation the anaerobic metabolism develops by the conversion of pyruvate to lactate in the muscle cells. The increase of lactate is immediately buffered by bicarbonate with the release of carbon dioxide. The carbon dioxide generated in the buffering process changes the respiratory volume and the compartment of gas. As a consquence of the increase in carbon dioxide output, the rate of rise of ventilation is accelerated while the oxygen uptake remains linear. This level of oxygen uptake which accelerates the rise of ventilation is defined as the anaerobic threshold (AT) by Wasserman et al.,7) and this index is considered to be of value in evaluating physical fitness. The maximal oxygen uptake can be measured by means of either a bicycle ergometer or a treadmill. The ergometer is commomly used in Europe, while the treadmill is used more in U.S.A.8) For the exercise loading, two methods are used: one, to increase the exercise load with small additions at one-minute intervals, and the other is to increase it with large additions at longer, 3–4 minute intervals. The former method is reported by Wasserman et al.5) to be more useful for the measurement of AT. Values of maximal oxygen uptake and anaerobic threshold vary with age, 9,10) sex,11) and level of physical activity.12,13) There are many reports of studies done on exercise tests and oxygen uptake on normal persons and athletes in other countries.4,11,13–16) In Korea only a few investigators have reported the maximal oxygen uptake in only a few selected subjects.17–19) It is the purpose of this study to measure normal values of maximal oxygen uptake and anaerobic threshold in a wide range of age groups and compile data which can be used in basic and clinical medicine.

14CO2-Assimilation, Translocation of 14C, and 14C-Carbonate Uptake in Different Organs of Spring Barley Plants in Relation to Adult-Plant Resistance to Powdery Mildew

Abstract: The cultivar Peruvian of spring barley, which is susceptible at all growth stages, and Asse, which exhibits adult-plant resistance to powdery mildew, were compared in 14CO2 assimilation, distribution of 14C, and 14C-carbonate uptake in different organs of healthy and infected plants. The reduction of 14CO2 assimilation in infected plants at the first and fourth leaf stages was greater in Peruvian than in Asse. In Peruvian, the 14C which was fixed by the infected third leaf of plants with mildew on the lower 3 leaves remained in the third leaves with very little translocation to other parts of the plant. Infection of the lower three leaves at the fourth leaf stage reduced 14CO2 assimilation in noninfected fourth leaves of Asse less than that of Peruvian, but the flow of 14C from the healthy fourth leaves into other plant parts such as leaf sheaths was markedly stimulated in Peruvian compared to Asse. Infection also reduced the uptake of 14C-carbonate by seedling roots, the reduction being greater in Peruvian than Asse. A greater proportion of the 14C absorbed by roots of Asse was translocated to the infected leaves than that of Peruvian. It was concluded that powdery mildew disrupted the normal pattern of photosynthesis and translocation of metabolites in a susceptible cultivar more markedly than in an adult-plant-resistant cultivar of spring barley.

A large pedunculated left ventricular thrombus with recurrent systemic thromboembolism in a young man.

Abstract: We present the case of a young man who has suffered from recurrent systemic thromboembolism since he developed an acute interior wall myocardial infarction at the age of 27. A large elongated, pendunculated left ventricular thrombus was found by two dimensional echocardiography and was successfully removed by open heart surgery.

Angular distributions of secondary relativistic charged particles produced in interactions of negative pions in emulsion at 300 GeV/c

Abstract: Angular-distribution data are presented of single relativistic charged particles produced in inelastic and incoherent negative-pion interactions with emulsion nuclei heavier than hydrogen at 300 GeV/c. The obtained results are compared with data from proton nuclei interactions at the same energy.

Acute Transverse Myelitis Complicated in Korean Hemorrhagic Fever: A Case Report and Review of the Literature

Abstract: Involvement of the central nervous system in Korean hemorrhagic fever is expected. When such involvement does occur, it is usually in the form of cerebral hemorrhage or pituitary necrosis. Paralytic disease due to Korean hemorrhagic fever is exceptional. A case of transverse myelitis in an adult female, in which a serologic test of immunofluorescent antibodies to Hantaan virus was positive with clinical pictures of Korean hemorrhagic fever, is reported here.

Utilization of Induced Abortion in Korea

Abstract: Compared to other developing countries in Asia, Korea is known to be one of the countries where population growth was fairly well reduced within a short period of time.