• Title/Summary/Keyword: Combined test

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Scintigraphic Findings of Nineteen Cases of Ectopic Thyroid (이소갑상선 19예의 신티그라피 소견)

  • Cho, In-Ho;Yoon, Hyun-Dae;Won, Kyu-Chang;Lee, Chan-Woo;Lee, Hyoung-Woo;Lee, Hyun-Woo;Lee, Jae-Tae;Lee, Kyu-Bo
    • The Korean Journal of Nuclear Medicine
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    • v.27 no.2
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    • pp.183-190
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    • 1993
  • Abnomalities in the embryologic development and migration of the thyroid gland can result in ectopic thyroid tissue, which may occur on the midline in any position from the base of the tongue to the mediastinum. Although ectopic thyroid may be asymptomatic, local obstructive, hemorrhagic or other complication may occur. Radinuclide thyroid scan is confirmatory when the diagnosis is suspected. Hypothyroidism is common in lingual thyroid, and thyroid supplementation is generally required. In order to evaluate the features of ectopic thyroid, we investigated the scintigraphic findings, thyroid function test and clinical symptoms of 19 patients with ectopic thyroid. 1) Th frequency of ectopic thyroid was about 5.3 times more common in female than in male. Then patients were mostly below 30 years old (79%). 2) The frequency of location of ectopic thyroid were as follows: 10 cases in the tongue base, 1 case in suprahyoid, 5 cases in infrahyoid and 3 cases over 2 areas. 3) The thyroid function test was done in 16 cases of the ectopic thyroid patients. The hypothyroidism was detected in 7 cases, subclinical hypothyroidism in 4 cases and normal thyroid function in 5 cases. 4) The rate of hypothyroidism is 90% in the lingual thyroid and 33% in the others. The thyroid dysfunction was related with the location of the ectopic thyroid (p < 0.05). 5) The clinical manifestations include a mass in the tongue base, the foreignbody sensation of a throat and a swallowing difficulty in lingual thyroid. The palpable mass was the chief complaint in the others. 6) We prescribed the thyroid hormone to 10 cases with hypothyroidism. The ectopic thyroid was removed in 2 cases with normal thyroid function. The rest is following up through OPD. We must consider the possibility of the ectopic thyroid and take the thyroid scan when the patient has a mass in the tongue base, the sublingual and the prelaryngeal area. Then we have to check the thyroid function and follow up when the ectopic thyroid is diagnosed, because the patient with normal thyroid function can result in the hypothyroidism. Except these, we must mind of the possibility of occurence of the cancer in the ectopic thyroid tissue.

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Capping Treatment for the Reduction of Phosphorus Release from Contaminated Sediments of Lakes (호소퇴적물로부터 인 용출 저감을 위한 Capping 처리)

  • Kim, Seog-Ku;Lee, Mi-Kyung;Ahn, Jae-Hwan;Yun, Sang-Leen;Kim, So-Jung
    • Journal of Korean Society of Environmental Engineers
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    • v.28 no.4
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    • pp.438-446
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    • 2006
  • A lab-scale batch test was conducted to develop capping materials to reduce the sediment phosphorus in the stagnant water zone of Gyeongancheon in Paldang Lake. The mean grain size(Mz) of sediment in the investigated area was 7.7 ${\phi}$, which is very fine, and the contents of organic carbon($C_{org}$) was 2.4%, which is very high. For the phosphorous release experiment to select the optimal capping material, sand layer, powder-gypsum($CaSO_4{\cdot}2H_2O$), granule-gypsum, complex layer(gypsum+sand) and the control were compared and evaluated in the 150 L reactor for 45 days. In case of the capping with the sand, it was found that the phosphorous from the sediment could be reduced by around 50%. However, it was found that this caused the reduction of the dissolved oxygen in the water column(by less than 3 mg/L) due to the resuspension of sediment and the organic matter decomposition that comes from the generation of $CH_4$ gas in the 1 cm of the sand layer. Therefore, it is likely that the sand layer has to be thickener in case of the sand capping. Powder-gypsum and granule-Gypsum reduced phosphorous release by more than 80%. However, the concentration of ${SO_4}^{2-}$ in the water column increased, making it difficult to apply it to the drinking water protection zone. We developed Fe-Gypsum and $SiO_2$-gypsum materials to reduce the solubility of ${SO_4}^{2-}$. Powder-Gypsum creates the interception film that does not have any aperture on the sediment layer when it is combined with the water. However phosphorous release caused by the generation of $CH_4$ gas may happen at a time when the gypsum layer has the crack. Capping through the complex layer(granule-Gypsum+sand(1 cm)) found to be suitable for the drinking water protection zone because it was effective to prevent phosphorus release. Moreover, this leads to the lower solubility from the concentration of ${SO_4}^{2-}$ into the water column than the powder-Gypsum and granule-Gypsum. The addition of gypsum($CaSO_4{\cdot}2H_2O$) into the sediment can reduce the progress of methanogensis because fast early diagenesis and sufficient supply of ${SO_4}^{2-}$ to the sediment, stimulate the SRB(sulfate reducing bacteria) highly.

The Effect of 6 Weeks of Treatment with Inhaled Budesonide on Bronchial Hyperresponsiveness and Adrenal Function in Asthmatic Patients (흡입용 스테로이드인 Budesonide 6주 치료가 기관지 천식환자의 기관지 과민반응과 부신피질기능에 미치는 영향)

  • Kim, Kwan-Hyoung;Oh, Yong-Seok;Kim, Chi-Hong;Kwon, Soon-Seog;Kim, Young-Kyoon;Han, Ki-Don;Moon, Hwa-Sik;Song, Jeong-Sup;Park, Sung-Hak
    • Tuberculosis and Respiratory Diseases
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    • v.39 no.3
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    • pp.219-227
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    • 1992
  • Background: Acute and chronic airway inflammation are important in the pathogenesis of bronchial asthma. Corticosteroids have proved to be very effective in the management of asthma. Although the mechanism by which they produce this effect is still debated, suppression of the inflammatory response is thought to be the most likely. Although inhaled steroids are known to be safe and have less side effects than oral steroids, the extent which inhaled steroids have beneficial and the detrimental effects in the treatment of asthma has remained open to question. Budesonide is a recently developed corticosteroid for inhalation treatment with a strong local effect combined with rapid inactivation in the systemic circulation. We set out to look in more detail at the time course of change in bronchial reactivity, clinical symptoms and the effects on the adrenal function during 6 weeks of treatment with budesonide (800 ug per day). Methods: Clinical symptoms, pulmonary function test, histamine $PC_{20}$, serum ACTH and cortisol (8 AM and 4 PM) were measured in 23 allergic asthmatic patients before and after 6 weeks of treatment with budesonide. Results: 1) Pulmonary function test; PEFR, FEV1 and FVC after 6 weeks of treatment with budesonide were higher than those before treatment. 2) Clinical symptoms; Clinical symptoms were significantly improved after 3 weeks and 6 weeks of treatment with budesonide. 3) Histamine provocation; Histamine $PC_{20}$ after 6 weeks of treatment with budesonide was significantly higher than that before treatment. 4) Adrenal function; 6 weeks of budesonide therapy did not significantly affect the level of serum ACTH and cortisol. Conclusion: From these results, it is concluded that budesonide therapy improved the clinical symptoms, pulmonary function and bronchial hyperreactivity after 3 weeks of treatment and the improvement after 6 weeks of treatment was higher than that after 3 weeks of treatment. During 6 weeks of treatment with budesonide, the inhibitory effect on the adrenal function was not obvious.

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Evaluation of the Clinical Usefulness of the Xeniss Rapid TB kit for the Diagnosis of Tuberculosis (결핵진단에서 Xeniss Rapid TB kit의 임상적 유용성)

  • Park, Seung-Kyu;Lee, Woo-Chul;Hwang, Soo-Hee;Kwon, Eun-Si;Lee, Hung-Soon;Lee, Duk-Hyoung
    • Tuberculosis and Respiratory Diseases
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    • v.53 no.4
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    • pp.389-400
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    • 2002
  • Background : The rapid diagnostic tests for tuberculosis are needed to facilitate early treatment of tuberculosis and prevention of Mycobacterium tuberculosis transmission. The Xeniss Rapid TB kit is a rapid, card-based immunochromatographic test for the detection of antibodies directed against M. tuberculosis antigens including antigen 5(38-kDa antigen). The objective of this study was to evaluate the performance of the Xeniss Rapid TB kit for the diagnosis of active tuberculosis with serums from patients, asymptomatic healthy and close contact controls. Methods : 188 patients with active tuberculosis were tested; 177 with pulmonary tuberculosis(18 with combined pleurisy), and 11 with extrapulmonary tuberculosis. The control groups were composed of 82 close contacts and 57 healthy adults. Study subject were drawn from one national tuberculosis hospital for patients and close contacts, and another private hospital for healthy adults in Masan city, Korea. The Xeniss Rapid TB kit(Xeniss Life Science Co., Ltd., Seoul, Korea) was evaluated by using serum samples according to the instructions of the manufacturer by an investigator masked to the clinical and microbiological status of the study subjects. Results : The diagnostic sensitivity of the Xeniss Rapid TB kit was 73.9% in patients and specificities were 73.2% and 93.0% in close contact and healthy adults respectively. The positive predictive value in patients was 84.2% and the negative predictive value in controls was 85.8%. Conclusion : This study shows that the Xeniss Rapid TB test is a simple and fast method to diagnose active TB. The results of the sensitivity and specificites suggest that serodiagnosis using this point of care testing(POCT) device would be valuable and advantageous for screening tuberculosis in the clinical field.

Design and Full Size Flexural Test of Spliced I-type Prestressed Concrete Bridge Girders Having Holes in the Web (분절형 복부 중공 프리스트레스트 콘크리트 교량 거더의 설계 및 실물크기 휨 실험 분석)

  • Han, Man Yop;Choi, Sokhwan;Jeon, Yong-Sik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.3A
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    • pp.235-249
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    • 2011
  • A new form of I-type PSC bridge girder, which has hole in the web, is proposed in this paper. Three different concepts were combined and implemented in the design. First of all, a girder was precast at a manufacturing plant as divided pieces and assembled at the construction site using post-tensioning method, and the construction period at the site will be reduced dramatically. In this way, the quality of concrete can be assured at the manufacturing factory and concrete curing can be well controlled, and the spliced girder segments can be moved to the construction site without a transportation problem. Secondly, a numerous number of holes was made in the web of the girder. This reduces the self-weight of the girder. But more important thing related to the holes is that about half of the total anchorages can be moved from the girder ends into individual holes. The magnitude of negative moment developed at girder ends will be reduced. Also, since the longitudinal compressive stresses are reduced at ends, thick end diaphragm is not necessary. Thirdly, Prestressing force was introduced into the member through multiple stages. This concept of multi-stage prestressing method overcomes the prestressing force limit restrained by the allowable stresses at each loading stage, and maximizes the magnitude of applicable prestressing force. It makes the girder longer and shallower. Two 50 meter long full scale girders were fabricated and tested. One of them was non-spliced, or monolithic girder, made as one piece from the beginning, and the other one was assembled using post-tensioning method from five pieces of segments. It was found from the result that monolithic and spliced girder show similar load-deflection relationships and crack patterns. Girders satisfied specific girder design specification in flexural strength, deflection, and live load deflection control limit. Both spliced and monolithic holed web post-tensioned girders can be used to achieve span lengths of more than 50m with the girder height of 2 m.

Analysis of Factors Influencing Entrepreneurial Performance at the University Level for Becoming Entrepreneurial Universities (기업가형 대학(Entrepreneurial University)을 위한 대학의 창업 성과 영향요인 분석)

  • Lim, Hanryeo;Hon, Sungpyo
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.15 no.2
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    • pp.19-32
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    • 2020
  • The purpose of this study was to investigate the influence factors of the university level centering on the entrepreneurial performance of the university students and full-time faculties in the situation of increasing interest in entrepreneurial university. In order to achieve the purpose of the study, a panel data was established from 2015 to 2018 on the basis of the university notification data. The panel data included universities with data on the number of university students and full-time faculty founders for at least two years. Through this, four year data from 154 universities were used for analysis. As an analysis method, frequency analysis and descriptive statistics were conducted to understand the characteristics of the university. Since then, panel negative binomial regression analysis has been conducted in consideration of the longitudinal features and distribution of the data. Also, based on the Hausman test results, the results were interpreted based on random effect model. The results of this study are as follows. First, as a result of the analysis of the entrepreneurial performance and the change trend of the domestic university from 2015 to 2018, the entrepreneurial performance of the university has been steadily increasing in the last four years, and the increase in the number of university student entrepreneurs was relatively higher than the full-time faculties. Second, economic and educational approaches need to be combined to promote university students' start-ups. The university factors that promote the start-up of university students were found to be scholarships, start-up grants, startup lectures, and startup clubs. Third, the openness and regional characteristics of the univeristy can promote the establishment of university students. Fourth, the establishment of a research environment and support for start-ups for full-time faculty members can enhance their start-up performance. The university factors that promote the start-up of full-time faculty were research funds and staffes who support start-up. The conclusions drawn from these findings are as follows. First, overall efforts are needed to develop into an entrepreneurial university. Second, in order to change into an entrepreneurial university, direct support for entrepreneurship is needed. Third, as an entrepreneurial university, it is necessary to find a way to bridge the gap by university according to region and size. Fourth, it is necessary to reinforce the support for linking the research results of universities to start-ups. Fifth, it is necessary to improve the atmosphere for full-time faculty members to be entrepreneur.

Quantitative Comparisons in $^{18}F$-FDG PET Images: PET/MR VS PET/CT ($^{18}F$-FDG PET 영상의 정량적 비교: PET/MR VS PET/CT)

  • Lee, Moo Seok;Im, Young Hyun;Kim, Jae Hwan;Choe, Gyu O
    • The Korean Journal of Nuclear Medicine Technology
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    • v.16 no.2
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    • pp.68-80
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    • 2012
  • Purpose : More recently, combined PET/MR scanners have been developed in which the MR data can be used for both anatometabolic image formation and attenuation correction of the PET data. For quantitative PET information, correction of tissue photon attenuation is mandatory. The attenuation map is obtained from the CT scan in the PET/CT. In the case of PET/MR, the attenuation map can be calculated from the MR image. The purpose of this study was to assess the quantitative differences between MR-based and CT-based attenuation corrected PET images. Materials and Methods : Using the uniform cylinder phantom of distilled water which has 199.8 MBq of $^{18}F$-FDG put into the phantom, we studied the effect of MR-based and CT-based attenuation corrected PET images, of the PET-CT using time of flight (TOF) and non-TOF iterative reconstruction. The images were acquired from 60 minutes at 15-minute intervals. Region of interests were drawn over 70% from the center of the image, and the Scanners' analysis software tools calculated both maximum and mean SUV. These data were analyzed by one way-anova test and Bland-Altman analysis. MR images are segmented into three classes(not including bone), and each class is assigned to each region based on the expected average attenuation of each region. For clinical diagnostic purpose, PET/MR and PET/CT images were acquired in 23 patients (Ingenuity TF PET/MR, Gemini TF64). PET/CT scans were performed approximately 33.8 minutes after the beginnig of the PET/MR scans. Region of interests were drawn over 9 regions of interest(lung, liver, spleen, bone), and the Scanners' analysis software tools calculated both maximum and mean SUV. The SUVs from 9 regions of interest in MR-based PET images and in CT-based PET images were compared. These data were analyzed by paired t test and Bland-Altman analysis. Results : In phantom study, MR-based attenuation corrected PET images generally showed slightly lower -0.36~-0.15 SUVs than CT-based attenuation corrected PET images (p<0.05). In clinical study, MR-based attenuation corrected PET images generally showed slightly lower SUVs than CT-based attenuation corrected PET images (excepting left middle lung and transverse Lumbar) (p<0.05). And percent differences were -8.01.79% lower for the PET/MR images than for the PET/CT images. (excepting lung) Based on the Bland-Altman method, the agreement between the two methods was considered good. Conclusion : PET/MR confirms generally lower SUVs than PET/CT. But, there were no difference in the clinical interpretations made by the quantitative comparisons with both type of attenuation map.

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A Study on the Effect of Cold Application Using a Sponge Bath in Healthy Adults (냉요법 적용방법에 따른 냉요법 효과에 관한 연구-건강한 성인 여성에서 스폰지 목욕방법을 중심으로)

  • Chung, Hyun-Sook;Kang, Kyu-Sook;Hwang, Ae-Ran
    • The Korean Nurse
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    • v.28 no.3
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    • pp.68-82
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    • 1989
  • This study was a quasi-experimental research study to test the characteristics of temperature regulation according to sponge bath methods of cold application. Thirteen volunteers were selected from among nursing college students according to an established criteria using a purposive sampling technique. Four different cold application methods were used: $\circled1$ tepid water sponge bath at $28^{\circ}C$, $\circled2$ 20% alcohol sponge bath at $28^{\circ}C$, $\circled3$ 40% alcohol sponge bath at $28^{\circ}C$ and $\circled4$ tepid water sponge bath at 28$^{\circ}$C plus an ice bag to the head. Changes in rectal temperature, mean skin temperature, mean body temperature, heat content change and thermal discomfort during the cold application were measured at 5 minute intervals over a 120 minute period. The data collection period was from Dec. 20, 1988 to Feb. 3, 1989. The data were analyzed using descriptive statistics, simple regression, ANOVA, Duncan's multiple range test and Pearson correlation coefficient using the SPSS-X Program. The results of the study are summarized as follows. Five general hypothesis were tested. Hypothesis 1 that "Change in heat content will be decreased for each cold application method according to the cold application time" was rejected. (tepid water sponge bath: after 10 minutes of cold application, 20% alcohol sponge bath: after 25 minutes of cold application: 40% alcohol sponge bath: after 45 minutes of cold application, tepid water sponge bath plus an ice bag to the head: after 80 minutes of cold application) Hypothesis 2 that "Thermal discomfort will be changed for each cold application method according to the cold application time" was rejected after 5minutes of cold application. Hypothesis 3 that "Change in heat content will differ among the cold application methods" was accepted except 0~5, 0~10, 0~65, 0~105 and 0~120 minute. This difference showed significance only between sponge bath methods and tepid water sponge bath plus an ice bag to the head. Hypothesis 4 that "Thermal discomfort will differ among the cold application methods" was accepted at 15, 20, 35, 45, 75, 80, 90, 95, 100, 105, 110, 115 and 120 minute of cold application time. This difference showed significance only between sponge bath methods and tepid water sponge bath plus an ice bag to the head. Hypothesis 5 that "The higher the change in heat content, the higher the thermal discomfort during the cold application time" was accepted for between 10~60 and 75 minute of cold application. In conclusion, this study showed that in sponge bath at $28^{\circ}C$, 10~80 minute was a effective cold application time in the view of heat loss through the skin. Concerning the effects of evaporation and thermal discomfort, it was found that there was no difference with regard to the solutions; tepid water sponge bath; 20% alcohol sponge bath or 40% alcohol sponge bath at a $28^{\circ}C$ controlled solution temperature. So it was thought that the type of solution itself did not have a big influence on the heat loss through skin. The combined effect of sponge bath with an ice bag to the head showed a significant difference and also showed a slight increase in thermal discomfort. On the basis of this research it can be concluded that cold application, for example, an ice bag to the head during a tepid water sponge bath is a good method as it increase heat loss through conduction, although fit can also cause a slight increase in thermal discomfort. The correlation between changes in heat content and thermal discomfort were not high. So factors other than change in heat content are considered to have an effect on the cognition of thermal discomfort.

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Optimum Rheological Mixed ratio of Jumbo Squid and Alaska Pollock Surimi for Gel Product Process (대형오징어와 명태혼합 어묵의 가열겔화시 물성에 영향을 미치는 최적 혼합비)

  • LEE Nahm-Gull;YOO Seung-Geun;CHO Young-Je
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.32 no.6
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    • pp.718-724
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    • 1999
  • This study was investigated the changes of the properties of matter such as the gel formation of the combined fish based on the mixed rate between the ocean jumbo squid and Alaska pollock surimi, and compared the relationships between the gel formation and water holding capacity. The changes of the gel formation based on 20 min fish grinding time and $2.5\%$ salt concentration according to the mixed rate was thought as the optimal addition limit. There was no significant function of gel product more than $20\%$ Jumbo squid meat. The more squid meat in the mixed meat could make the lower breaking stress but 7:3 rate of pollock : squid could retain breaking strain. The effect of the moisture content on mixed fish meat was studied and the drastic decrease of the gel formation and water holding capacity was indicated in $78\%$.

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An Examination of Knowledge Sourcing Strategies Effects on Corporate Performance in Small Enterprises (소규모 기업에 있어서 지식소싱 전략이 기업성과에 미치는 영향 고찰)

  • Choi, Byoung-Gu
    • Asia pacific journal of information systems
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    • v.18 no.4
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    • pp.57-81
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    • 2008
  • Knowledge is an essential strategic weapon for sustaining competitive advantage and is the key determinant for organizational growth. When knowledge is shared and disseminated throughout the organization, it increases an organization's value by providing the ability to respond to new and unusual situations. The growing importance of knowledge as a critical resource has forced executives to pay attention to their organizational knowledge. Organizations are increasingly undertaking knowledge management initiatives and making significant investments. Knowledge sourcing is considered as the first important step in effective knowledge management. Most firms continue to make an effort to realize the benefits of knowledge management by using various knowledge sources effectively. Appropriate knowledge sourcing strategies enable organizations to create, acquire, and access knowledge in a timely manner by reducing search and transfer costs, which result in better firm performance. In response, the knowledge management literature has devoted substantial attention to the analysis of knowledge sourcing strategies. Many studies have categorized knowledge sourcing strategies into intemal- and external-oriented. Internal-oriented sourcing strategy attempts to increase firm performance by integrating knowledge within the boundary of the firm. On the contrary, external-oriented strategy attempts to bring knowledge in from outside sources via either acquisition or imitation, and then to transfer that knowledge across to the organization. However, the extant literature on knowledge sourcing strategies focuses primarily on large organizations. Although many studies have clearly highlighted major differences between large and small firms and the need to adopt different strategies for different firm sizes, scant attention has been given to analyzing how knowledge sourcing strategies affect firm performance in small firms and what are the differences between small and large firms in the patterns of knowledge sourcing strategies adoption. This study attempts to advance the current literature by examining the impact of knowledge sourcing strategies on small firm performance from a holistic perspective. By drawing on knowledge based theory from organization science and complementarity theory from the economics literature, this paper is motivated by the following questions: (1) what are the adoption patterns of different knowledge sourcing strategies in small firms (i,e., what sourcing strategies should be adopted and which sourcing strategies work well together in small firms)?; and (2) what are the performance implications of these adoption patterns? In order to answer the questions, this study developed three hypotheses. First hypothesis based on knowledge based theory is that internal-oriented knowledge sourcing is positively associated with small firm performance. Second hypothesis developed on the basis of knowledge based theory is that external-oriented knowledge sourcing is positively associated with small firm performance. The third one based on complementarity theory is that pursuing both internal- and external-oriented knowledge sourcing simultaneously is negatively or less positively associated with small firm performance. As a sampling frame, 700 firms were identified from the Annual Corporation Report in Korea. Survey questionnaires were mailed to owners or executives who were most erudite about the firm s knowledge sourcing strategies and performance. A total of 188 companies replied, yielding a response rate of 26.8%. Due to incomplete data, 12 responses were eliminated, leaving 176 responses for the final analysis. Since all independent variables were measured using continuous variables, supermodularity function was used to test the hypotheses based on the cross partial derivative of payoff function. The results indicated no significant impact of internal-oriented sourcing strategies while positive impact of external-oriented sourcing strategy on small firm performance. This intriguing result could be explained on the basis of various resource and capital constraints of small firms. Small firms typically have restricted financial and human resources. They do not have enough assets to always develop knowledge internally. Another possible explanation is competency traps or core rigidities. Building up a knowledge base based on internal knowledge creates core competences, but at the same time, excessive internal focused knowledge exploration leads to behaviors blind to other knowledge. Interestingly, this study found that Internal- and external-oriented knowledge sourcing strategies had a substitutive relationship, which was inconsistent with previous studies that suggested complementary relationship between them. This result might be explained using organizational identification theory. Internal organizational members may perceive external knowledge as a threat, and tend to ignore knowledge from external sources because they prefer to maintain their own knowledge, legitimacy, and homogeneous attitudes. Therefore, integrating knowledge from internal and external sources might not be effective, resulting in failure of improvements of firm performance. Another possible explanation is small firms resource and capital constraints and lack of management expertise and absorptive capacity. Although the integration of different knowledge sources is critical, high levels of knowledge sourcing in many areas are quite expensive and so are often unrealistic for small enterprises. This study provides several implications for research as well as practice. First this study extends the existing knowledge by examining the substitutability (and complementarity) of knowledge sourcing strategies. Most prior studies have tended to investigate the independent effects of these strategies on performance without considering their combined impacts. Furthermore, this study tests complementarity based on the productivity approach that has been considered as a definitive test method for complementarity. Second, this study sheds new light on knowledge management research by identifying the relationship between knowledge sourcing strategies and small firm performance. Most current literature has insisted complementary relationship between knowledge sourcing strategies on the basis of data from large firms. Contrary to the conventional wisdom, this study identifies substitutive relationship between knowledge sourcing strategies using data from small firms. Third, implications for practice highlight that managers of small firms should focus on knowledge sourcing from external-oriented strategies. Moreover, adoption of both sourcing strategies simultaneousiy impedes small firm performance.