• Journal of Bio-Environment Control
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• v.29 no.2
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• pp.141-152
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• 2020

The rapid on-site measurement of hydroponic nutrients allows for the more efficient use of crop fertilizers. This paper reports on the development of an embedded on-site system consisting of multiple ion-selective electrodes (ISEs) for the real-time measurement of the concentrations of macronutrients in hydroponic solutions. The system included a combination of PVC ISEs for the detection of NO₃, K, and Ca ions, a cobalt-electrode for the detection of H₂PO₄, a double-junction reference electrode, a solution container, and a sampling system consisting of pumps and valves. An Arduino Due board was used to collect data and to control the volume of the sample. Prior to the measurement of each sample, a two-point normalization method was employed to adjust the sensitivity followed by an offset to minimize potential drift that might occur during continuous measurement. The predictive capabilities of the NO₃ and K ISEs based on PVC membranes were satisfactory, producing results that were in close agreement with the results of standard analyzers (R² = 0.99). Though the Ca ISE fabricated with Ca ionophore II underestimated the Ca concentration by an average of 55%, the strong linear relationship (R² > 0.84) makes it possible for the embedded system to be used in hydroponic NO₃, K, and Ca sensing. The cobalt-rod-based phosphate electrodes exhibited a relatively high error of 24.7±9.26% in the phosphate concentration range of 45 to 155 mg/L compared to standard methods due to inconsistent signal readings between replicates, illustrating the need for further research on the signal conditioning of cobalt electrodes to improve their predictive ability in hydroponic P sensing.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.12 no.4
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• pp.1-14
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• 2017

New business management methods different from the past are necessary because of the rapid changes of the corporates' environment. KOSDAQ(Korean Securities Dealers Automated Quotation) companies should be expected the more affirmative business performance of companies by listing, but it is a well-known that they have problems of low business performance mostly. This paper aims to investigate the influential factors on enhancing corporate innovation and nonfinantial business performance, and to clarify practical measures and present a solution of KOSDAQ companies' problems through analysis of previous researches and an empirical research. This research present corporate entrepreneurship and human resources innovation as impact factors on the business performance to apply finely the path of technological innovation for the solution of the relevance investigation limit between the complexity of corporates' innovation paths and the firms' performance. And also knowledge management activities and external networks management or the firms have been adopted as a corporate innovation activities for free from quantitative measures, such as conventional research and development(R&D) activities by considering recent corporates' knowledge business operations. The results of the empirical analysis shows that significant impact factors on corporate innovation activities are the firms' propensities of competitive advantage initiative, risk taking and chief executive officer's innovation. These can be interpreted that the CEOs' innovation propensity should be enhanced for stimulating corporate's innovaton activities, which include the CEOs' interest in the development of new technology, the exploiting new businesses and their support of the innovation discipline for employees. In addition, it can be said that it is necessary to intensify more initiatives within those enterprise for enhancing the competitive advantage in the identical industry. The significant impact factors of corporate entrepreneurship and human resource innovation on the non-financial performance are resulted as the propensities of firms' competitive advantage initiative, CEOs' innovation and employees' innovaton. This shows that the higher propensities of firms' competitive advantage initiative, CEOs' innovation and employees' innovaton, the higher the cognitive degrees of business performance within each corporate, which include the members' awareness about firms' sales growth, market share growth, profit ratio growth, customers' preference and corporates' awareness.

• Progress in Medical Physics
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• v.9 no.2
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• pp.77-88
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• 1998

Wedge shaped isodoses are desired in a number of clinical situations. Hard wedge filters have provided nominal angled isodoses with dosimetric consequences of beam hardening, increased peripheral dosing, nonidealized gradients at deep depths along with the practical consequendes of filter handling and placement problems. Dynamic wedging uses a combination of a moving collimator and changing monitor dose to achieve angled isodoses. The segmented treatment tables(STT) that monitor unit setting by every distance of moving collimator, was induced by numerical formular. The characteristics of dynamic wedge by STT compared with real dosimetry. Methods and Materials : The accelerator CLINAC 2100C/D at Yonsei Cancer Center has two photon energies (6MV and 10MV), currently with dynamic wedge angles of 15$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$ and 60$^{\circ}$. The segmented treatment tables(STT) that drive the collimator in concert with a changing monitor unit are unique for field sizes ranging from 4.0cm to 20.0cm in 0.5cm steps. Transmission wedge factors were measured for each STT with an standard ion chamber. Isodose profiles, isodose curves, percentage depth dose for dynamic wedge filters were measured with film dosimetry. Dynamic wedge angle by STT was well coincident with film dosimetry. Percent depth doses were found to be closer to open field but more shallow than hard wedge filter. The wedge transmission factor were decreased by increased the wedge angle and more higher than hard wedge filters. Dynamic wedging probided more consistent gradients across the field compared with hard wedge filters. Dynamic wedging has practical and dosimetric advantages over hard filters for rapid setup and keeping from table collisions. Dynamic wedge filters are positive replacement for hard filters and introduction of dynamic conformal radiotherapy and intensity modulation radiotherapy in a future.

• Journal of agricultural medicine and community health
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• v.40 no.3
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• pp.115-125
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• 2015

Objectives: Colorectal cancer is one of the major cancers in South Korea. We described the time trends in colorectal cancer incidence in Daejeon, a metropolitan city, and Chungcheongnam-do (Chungnam), a rural province, South Korea. Methods: Using the databases from the Daejeon Cancer Registry (DCR) and the Chungnam Cancer Registry (CCR), age-standardized (to world standard population) rates for incidence (ASRW) were calculated. Average annual percent change (AAPC) was assessed as a trend indicator. The completeness (such as the mortality/incidence ratio) and validity (such as the death certificate only %, microscopic verification %, primary site uncertain %, and age unknown %) were analyzed to examine the data quality of DCR and CCR. Results: Incidence of colorectal cancer showed increasing trend in both sexes. Over the years 2000-2012 in Daejeon, ASRW was increased significantly from 37.2 to 51.7 per 100,000 person-years (AAPC, 3.9%) among men and from 17.1 to 28.4 (AAPC, 3.9%) among women, respectively. In Chungnam, ASRW was also increased from 29.8 to 50.1 per 100,000 person-years (AAPC, 5.1%) among men and from 15.9 to 26.6 (AAPC, 3.2%) among women, respectively. The AAPC for colon cancer was greater than rectal cancer in both Daejeon and Chungnam. The trend of rectal cancer incidence was differ by sex (AAPC in men vs women, 2.7% vs 1.7% in Daejeon; 3.5% vs 0.8% in Chungnam). Indices of completeness and validity showed that the quality control of DCR and CCR was adequate to describe the trends of ASRW. Conclusions: Both Daejeon and Chungnam have had a rapid increase in colorectal cancer incidence. Monitoring and intervention are required on the risk factors which may contribute to this trend.

• Journal of agricultural medicine and community health
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• v.34 no.2
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• pp.155-167
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• 2009

Objectives: The purpose of this study was to investigate healthy city project related characteristics to members of the Korea Healthy Cities Partnership(KHCP). Methods: This study analyzed general characteristics of healthy city, characteristics of healthy city(political support, collaboration & citizen participation, healthy city project, infrastructure development, capacity building), self-evaluation of healthy city and etc by self-questionnaires from February to December, 2007, which were distributed to government workers who were in charged in health city project of 23 membership cities of KHCP. Results: The number of urban city was 11(47.8%) and that of rural municipality was 12(52.5%). Public health center was almost in charge of healthy city project(73.9%). As for the characteristics of healthy city, healthy city municipal budget(91.3%), city health profile(91.3%), technical support of cooperative university(82.6%), healthy city regulation(78.3%), citizen participation(78.3%), committee(73.9%), setting approach(69.9%) and healthy city network(69.6%) were good. But intersectoral collaboration(34.8%), long-term healthy city plan(39.1%), administrative policy or campaign promise(43.5%), programs to the vulnerable population(47.8%), department in charge(47.8%) and seminar(47.8%) were not good. Especially, characteristics of healthy city according to the existence of department in charge were significantly different in intersectoral collaboration, citizen participation, setting approach and healthy city network. Conclusions: In spite of rapid expansion in healthy cities, there were great difficulty in political support, collaboration, department in charge and programs of health equity. So we need to go a long way to achieve the vision of healthy cites by its principles and characteristics.

• Tuberculosis and Respiratory Diseases
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• v.43 no.2
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• pp.159-163
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• 1996

Background : In case of tuberculous pneumonia, differentiation from bacterial lobar pneumonia is sometimes very difficult because clinical symptoms, signs and radiological images are very similar. So we investigated the usefulness of CA125, which is known to increase in tuberculous diseases, in differential diagnosis between tuberculous pneumonia (TBPN) and community acquired bacterial lobar pneumonia (LP). Methods : Serum CA125 level was measured in 20 patients with TBPN (female 12 male 8 : mean age 36.1 years) and 14 patients with LP (female 5 male 9 : mean age 45.1 years) by radioimmunoassay (Centocor(R) CA125 RIA kit). Results : 1) The serum CA125 level in TBPN ($333.7{\pm}283.5\;u/ml$) was higher than in LP ($60.9{\pm}66.2\;u/ml$). (P < 0.05) 2) If we took cut-off value as 195 u/ml in differential diagnosis between TBPN and LP, the sensitivity and specificity of CA125 level in the diagnosis of TBPN were 70% and 93%, respectively. 3) There was no significant difference in serum CA125 level between noncavitary TBPN ($242.1{\pm}76.6\;u/ml$, n=10) and cavitary TBPN ($399.6{\pm}318.4\;u/ml$, n=10). (P > 0.05) 4) Following up of serum CA125 level after initiation of antituberculosis treatment showed rapid decline and approach to near normal range in 6 months. Conclusion : High serum CA125 level (> 195 u/ml) was useful in differential diagnosis of TBPN from LP.

• Tuberculosis and Respiratory Diseases
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• v.44 no.3
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• pp.574-582
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• 1997

Background : Normal humans meet the increased ventilatory need during exercise initially by the increase of tidal volume (TV) and later by the increase of respiratory frequency (Rf). And the inspiratory duty cycle (Ti/Ttot) is also increased more than 50% for the compensation of the decrease of respiratory cycle provoked by the increase of respiratory frequency. The patients with chronic airflow obstruction show rapid and shallow breathing pattern during exercise because of the decreased ventilatory capacity and the increased dead space ventilation. However, the studies about the change of inspiratory duty cycle are only a few and there is no literature about the relationship between the change of inspiratory duty cycle and the degree of airflow obstruction. Methods : The subjects were the twelve patients with chronic airflow obstruction (CAO) and ten normal people. The incremental exercise test was done. The increase of work load was 10 W in CAO group and 25 W in normal control group. The analysis of the results was done by the comparison of the parameters such as minute ventilation (VE), TV, Rf, physiologic dead space (Vd/Vt), and inspiratory duty cycle between the two groups. Each parameters were compared after transformation into % control duration base that means dividing the total exercise time into five fractions and % control duration data were obtained at rest, 20%, 40%, 60%, 80%, and max. Statistical analysis was done by repeated measure ANOVA using SAS program. Results : The changes of VE and TV were significantly different between two groups while the change of Rf was not significant. The decrease of Vd/Vt was significantly low in CAO group. Ti/Ttot was markedly increased from 38.4 + 3.0% at rest to 48.6 + 4.5% at max in normal control group while Ti/Ttot showed little change from 40.5 + 2.2% at rest to 42.6 + 3.5% at max. And the change of inspiratory duty cycle showed highly good correlation with the degree of airflow obstruction (FEV1%). (r=0.8151, p < 0.05). Conclusions : The increase of Ti/Ttot during exercise observed in normal humans is absent in the patients with CAO and the change of Ti/Ttot is well correlated with the degree of airflow obstruction.

• Tuberculosis and Respiratory Diseases
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• v.50 no.1
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• pp.94-105
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• 2001

Background : Examining the biological susceptibility of Mycobacterium tuberculosis to pyrazinamide (PZA) in vitro is very difficult as PZA is inactive under normal culture conditions. The biological susceptibility test, an enzyme assay for Pzase activity, and a genetic test for pncA gene mutations, were performed in order to predict PZA resistance. Methods : 28 cultured clinical isolates of Mycobacterium tuberculosis were tested. The biological susceptibility was performed by the absolute concentration method using Lowenstein-Jensen media. The PZase activity was tested by means of Wayne's method. A 710-bp region includes the entire open reading frame of pncA was amplified and sequenced. Results : All six strains with positive PZase activity exhibited no pncA mutations with one strain showing a false resistance in the biological susceptibility test. Among the 22 strains with no PZase activity, 21 exhibited showed pncA mutations. In the biological susceptibility test, 20 strains were resistant, and one was susceptible, and the other flied to test. The mutation types varied with ten missense, one silent and one nonsense mutation 1 slipped-strand mispairing, and 6 frameshift mutations. Three strains had an adenine to guanine mutation at position -11 upstream of the start codon. Conclusion : The mutation at the pncA promotor region is frequent at -11 upstream position. Automatic sequencing of pncA is a useful tool for rapid and accurate detection of PZA resistant M. tuberculosis, and for demonstrating the epidemiological relatedness of the PZA resistant M. tuberculosis strains.

• Journal of the Mineralogical Society of Korea
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• v.22 no.4
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• pp.359-370
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• 2009

Arsenic and heavy metals leached out as a result of oxidation of tailings exposed to the surface pose a serious environmental contamination of mine areas. This study investigated how arsenic behavior is controlled by a variety of processes, such as oxidation of sulfides and formation or alteration of secondary minerals, based on mineralogical methods. The study was carried out using the tailing samples obtained from Nakdong mine located in Jeongseongun, Gangwondo. After separating magnetic and non-magnetic minerals using pretreated tailing samples, each mineral sample was classified according to their colors and metallic lusters observed by the stereoscopic microscope. Subsequently, the mineralogical properties were determined using various instrumental analyses, such as x-ray diffractometer (XRD), energy dispersive spectroscopy (EDS), and electron probe micro analyzer (EPMA). The literature review confirmed that various ore minerals were identified in the Nakdong ore deposits. In this study, however, there were observed a few original ore minerals as well as secondary and/or tertiary minerals newly formed as a result of weathering including oxidation. In particular, we did not recognize pyrrhotite which has been known to originally exist in a large abundance, but peculiarly colloform-type iron (oxy)hydroxides were identified, which indicates most of pyrrhotite has been altered by rapid weathering due to its large reactivity. In addition, a secondary scorodites filling the fissure of weathered primary arsenopyrites were identified, and it is speculated that arsenic is immobilized through such a alteration reaction. Also, we observed tertiary iron (oxy)hydroxides were formed as a result of re-alteration of secondary jarosites, and it suggests that the environment of tailing has been changed to high pH from low pH condition which was initiated and developed by oxidation reactions of diverse primary ore minerals. The environmental change is mainly attributed to interactions between secondary minerals and parental rocks around the mine. As a result, not only was the stability of secondary minerals declined, but tertiary minerals were newly formed. As such a process goes through, arsenic which was immobilized is likely to re-dissolve and disperse into surrounding environments.

• Tuberculosis and Respiratory Diseases
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• v.56 no.3
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• pp.261-268
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• 2004

Background : The resurgence of tuberculosis and outbreaks of multidrug resistant (MDR) tuberculosis have increased the emphasis for the development of new susceptibility testing of the Mycobacterium tuberculosis for the effective treatment and control of the disease. Conventional drug susceptibility testings, such as those using egg-based or agar-based media have some limits, such as the time required and difficulties in determining critical inhibitory concentrations, but these are still being used in many diagnostic laboratories because of no better lternatives, considering cost and accuracy. To overcome these limits, a rapid and simple method for new susceptibility testing, using live and dead assays, was applied for a bacterial cell viability assay to distinguish dead from live bacterial cells based on two-color fluorescence. Materials and Methods Strains : Forty strains were used in this study, 20 susceptible to all antituberculosis drugs and the other 20 resistant to the four first line antituberculosis drugs isoniazid, rifampicin, streptomycin and ethambutol. Antibiotics : The four antibiotics were dissolved in 7H9 broth to make the following solutions: $0.1{\mu}g\;isoniazid(INH)/m{\ell}$, $0.4{\mu}g\;rifampicin(RMP)/m{\ell}$, $4.0{\mu}g\;streptomycin(SM)/m{\ell}$ and $4.0{\mu}g\;ethambutol(EMB)/m{\ell}$. Results : Live and dead Mycobacterium tuberculosis cells fluoresced green and red with the acridin (Syto 9) and propidium treatments, respectively. These results are very well accorded with conventional drug susceptibility testing by proportional method on Lowensen-Jensen media (L-J) containing 4 drugs (INH, RMP, EMB and SM), showing a 93.7 % accordance rate in susceptible strains and 95% in resistant strains. Conclusion : The results of the drug susceptibility testing using the live and dead bacterial cell assay showed high accordance rates compared with the conventional proportion method on L-J. This finding suggests that the live and dead bacterial cell assay can be used as an alternative to conventional drug susceptibility testing for M. tuberculosis strains.