• 제목/요약/키워드: Difference-in-differences

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Differences in Sodium-Intake Related Dietary Behaviors and Correlation Analysis According to Salty Taste Preference of University Students in Busan Area (부산지역 대학생의 짠맛 선호도에 따른 소금 섭취 식행동 차이와 상관성 분석)

  • Kang, Min-Ji;Choi, Ki-Bo;Lyu, Eun-Soon
    • Korean journal of food and cookery science
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    • v.31 no.4
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    • pp.477-484
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    • 2015
  • The objective of this study was to investigate the awareness of the meaning of a low-sodium diet as well as the self-reported preference of saltiness and sodium-intake related dietary behaviors for university students in Busan. A survey was conducted with 977 students (male: 512, female: 465). For the self-reported preference of saltiness, 45.8% of the participants reported 'moderate' preference, 35.3% reported 'salty' preference, and 18.8% reported 'unsalty' preference. Males had significantly higher scores than females (p<0.01). Regarding awareness of the meaning of a low-sodium diet, 20.8 % of the students did not recognize the phraseand, males had significantly lower awareness than females (p<0.01). The 'salty' group had a significantly lower rate than others (p<0.01). Males had significant higher sodium-related dietary behaviors scores than females for the following questions 'I often eat dried seafood and salted seafood', 'I usually eat all the broth in soups or stews' (p<0.01), 'I usually eat a lot of kimchi and salt-pickled vegetables', 'I usually eat soy dip or hot pepper dip with sushi and fritters' (p<0.05). Mean scores for sodium-related dietary behaviors by self-reported preference of saltiness were 2.49/5.00 (unsalty), 2.87/5.00 (moderate), and 3.19/5.00 (salty), respectively. There was a statistically significant difference between the groups (p<0.01). The lower the scores for the self-reported preference of saltiness, the lower the scores for sodium intake-related dietary behaviors (p<0.01). The average score for sodium-related dietary behaviors in the group familiar with the meaning of a low-sodium diet was significantly lower than that of the group that 'did not know' (p<0.01).

The Study on the Seasonal Variation of Microbial Community in Kyeonggi Bay, Korea 1. Bacteria and Heterotrophic nanoflagellates (경기만 수역에서 미세생물 군집의 계절적 변동 연구 I. 박테리아와 종속영양 미소 편모류)

  • 양은진;최중기;현정호
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.8 no.1
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    • pp.44-57
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    • 2003
  • Seasonal variations of bacterial abundance and production, heterotrophic nanoflagellate (HNF) abundance and HNF ingestion rates on bacteria using FLB together with environmental variables were investigated at intervals of a month in Kyeonggi Bay from December 1991 to November 1998. Bacterial abundance and production ranged from 0.38$\times$10$^{9}$ ~ 3.25$\times$10$^{9}$ cells 1$^{-1}$ (average 1.19$\pm$0.69$\times$10$^{9}$ cells 1$^{-1}$ ) and from 1.51 to 20.4 cells 1$^{-1}$ h$^{-1}$ (average 6.04$\pm$ 1.88$\times$10$^{6}$ cells 1$^{-1}$ h$^{-1}$ ), respectively. Bacterial abundance and production showed no differences at the high tide and low tide, and bacterial abundances were not different with depth, but bacterial production decreased with depth. Seasonal variation of bacterial abundance showed almost similar fluctuation pattern to those of DOC (dissolved organic carbon). HNF abundances ranged from 388 to 4,374 cells ml$^{-1}$ (average 1,344$\pm$130 cells ml$^{-1}$ ), were high in March, April, July and August. HNF abundance showed no difference between the high tide and low tide, and was not different with depth. The ingestion rates of HNF on bacteria were 1.0 to 6.3$\pm$10$^{6}$ bacteria 1$^{-1}$ h$^{-1}$ (average 3.12$\pm$0.55$\times$10$^{6}$ bacteria 1$^{-1}$ h$^{-1}$ ), resulting ingestion rates of HNF removed 19.4 to 141.4 %(average 62.3$\pm$12.0%) of bacterial production. Ingestion rates and grazing pressure of HNF on bacteria showed high correlation with HNF abundance. Although we cannot exactly discussion about seasonal variation of bacteria community in this study area where physical and chemical parameters were very complex, the results indicate that bacterial abundance and production were mainly controlled by resources supply as dissolved organic carbon and chlorophyll-a(bottom-up) except March which bacterial abundance and production uncoupled chlorophyll-a because of low dissolved organic carbon and low temperature, and were controlled by HNF grazing pressure(top-down) in the warm seasons except the winter.

Influence of Cerebral Protection Methods in Thoracic Aortic Surgery Using Hypothermic Circulatory Arrest (저체온 순환정지를 이용한 흉부 대동맥 수술 시 뇌관류 방법에 따른 수술결과)

  • Kim, Jae-Hyun;Na, Chan-Young;Oh, Sam-Sae
    • Journal of Chest Surgery
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    • v.41 no.2
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    • pp.229-238
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    • 2008
  • Background: Protection of the brain is a major concern during thoracic aortic surgery using hypothermic circulatory arrest (HCA). This study compares the surgical outcomes of two different cerebral protection methods in thoracic aortic surgery using HCA: retrograde cerebral protection (RCP) and antegrade cerebral protection (ACP). Material and Method: We retrospectively reviewed data on 146 patients who underwent thoracic aortic surgery from May 1995 to February 2007 using either RCP (114 patients, Group 1) or ACP (32 patients, Group 2) during HCA. There were 104 dissections (94 acute and 10 chronic) and 42 aneurysms (41 true aneurysms and 1 pseudoaneurysm), and all patients underwent ascending aortic replacement. There were 33 cases of hemiarch replacement, 5 of partial arch replacement, and 21 of total arch replacement. Result: The two groups were similar in preoperative and operative characteristics, but Group 2 had more elderly (over 70 years old) patients (34.4% vs. 10.5%), more coronary artery diseases (18.8% vs. 4.4%), more total arch replacements (46.9% vs. 5.3%) and longer HCA time ($50{\pm}24$ minutes vs. $32{\pm}17$ minutes) than Group 1. The operative mortality was 4.4% (5/114) and 3.1% (1/32), the incidence of permanent neurologic deficits was 5.3% (6/114) and 3.1% (1/32), and the incidence of temporary neurologic deficits was 1.8% (2/114) and 9.4% (3/32) in Groups 1 and 2, respectively. There were no statistical differences between the two groups in operative mortality, postoperative bleeding, or neurologic deficits (permanent and temporary). Conclusion: The early outcomes of aortic surgery using HCA were favorable and showed no statistical difference between RCP and ACP. However, the ACP patients endured longer HCA times and more extended arch surgeries. ACP is the preferred brain protection technique when longer HCA time is expected or extended arch replacement is needed.

Physicochemical Properties of Organic Milk and Conventional Milk from Chungnam and Jeonbuk, Korea (한국 충남 및 전북에서 생산된 유기우유와 일반우유의 이화학적 특성에 관한 연구)

  • Ki, Kwang Seok;Lim, Dong Hyun;Park, Seong Min;Lim, Hyun Joo;Park, Su Bum;Kim, Tae Il;Jeong, Seok Geun;Baek, Kwang Soo;Kwon, Eung Gi;Lee, Se Young
    • Korean Journal of Food Science and Technology
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    • v.47 no.3
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    • pp.359-363
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    • 2015
  • This study was conducted to investigate the differences in the physicochemical properties of organic and conventional milk from Chungnam and Jeonbuk, Korea. The milk was collected from 10 organic and 10 conventional milk farms in February, March and August, and then analyzed for milk composition, minerals and fatty acids. Organic milk showed lower fat (p<0.01) and total solid (p<0.05), but higher phosphorous (p<0.01) content than conventional milk. However, there was no difference in the content of lactose or the somatic cell count. Organic milk showed lower (p<0.01) stearic acid and total saturated fatty acid content, but higher (p<0.01) total, mono-, and poly-unsaturated fatty acid content. These results showed that organic and conventional milks differ mainly in their fat and unsaturated fatty acid content. Due to increasing consumer interest in food safety and health, organic milk, which contains more beneficial fatty acids, might be preferred over conventional milk.

An effect of Dentin Bonding Procedure on the Shear Bond Strength of Resin Cement to Porcelain Restoration (도재 수복물 합착시 상아질 접착 술식이 레진 시멘트의 전단결합강도에 미치는 영향)

  • Kang, Hae-Jin;Shin, Soo-Yeon
    • Journal of Dental Rehabilitation and Applied Science
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    • v.28 no.1
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    • pp.67-78
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    • 2012
  • The purpose of this study was to determine whether there were differences in shear bond strength to human dentin using IDS technique compared with DDS. Forty freshly extracted human molars were and devided into 4 groups. The control group specimens were, on the morrow of tooth preparation, light-cured after application of dentin bonding agent and cemented with resin cement. The IDS/SE(immediate dentin sealing, Clearfil$^{TM}$ SE Bond) and IDS/SB (immediate dentin sealing, Adapter$^{TM}$ Single Bond 2) specimens were, on the morrow of tooth preparation, light-cured after application of dentin bonding agent(Clearfil$^{TM}$ SE Bond and Adapter$^{TM}$ Sing Bond 2, respectively), whereas DDS specimens were not treated with any dentin bonding agent. IDS/SE, IDS/SB and DDS specimens were thermocycled. Following that delay, specimens were cemented with resin cement. The dentin bonding agent was left unpolymerized until the application of porcelain restoration. Shear bond strengths were measured using a universal testing machine. Specimens also were evaluated for mode of fracture using an optical microscope. The mean shear bond strengths of control group and IDS/SE groups were not statistically different from one another. The bond strength of IDS/SE group had a significantly higher mean than that of DDS group. There was no significant difference in the mean shear bond strength between IDS/SB(4.11MPa) and DDS group. The evaluation of failure modes indicates that most failures in the control group and IDS/SE groups were mixed, whereas failures in the DDS group were interfacial. When preparing teeth for indirect ceramic restoration, IDS with Clearfil$^{TM}$ SE Bond results in improved shear bond strength compared with DDS.

Effect of calcium chloride on the texture of pickled radish wrap (염화칼슘 첨가에 따른 쌈무의 조직감 개선 효과)

  • Jeong, Eun-Jeong;Lee, Nam Keun;Yum, Eun Ji;Nam, Kang;Oh, Jisun;Kim, Yong-Sik;Park, Jun-Young;Kim, Su-Jeong;Jeong, Yong-Seob
    • Food Science and Preservation
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    • v.22 no.3
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    • pp.452-457
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    • 2015
  • This study was conducted to evaluate the quality characteristics of pickled radish wrap supplemented with calcium chloride ($CaCl_2$) at different concentrations. With $CaCl_2$ supplementation, initial pH and acidity were 3.8~4.0 and 2.7~3.0% (w/v), respectively. During the 28 day-preservation at $4^{\circ}C$ or $50^{\circ}C$, the initial pH and acidity were maintained. However, when the pickled radish wrap was preserved at $25^{\circ}C$, it had lower pH (by 0.5) and higher acidity (by 1.9~2.2%) when compared with the initial values. The difference in color (${\Delta}E$-value) of the pickled radish wrap preserved at $50^{\circ}C$ was significant (${\Delta}E$-value 23~27), though the hardness of the sample prepared at $4^{\circ}C$ or $25^{\circ}C$ showed no distinguishable differences at various concentrations of $CaCl_2$ supplementation (0.1, 0.2, 03, 0.4, and 0.5%). However, once preserved at $50^{\circ}C$, it resulted in the greater hardness with the higher concentrations of $CaCl_2$ supplementation. In terms of softness, the overall trend in changes was similar to the hardness. A sensory evaluation using the samples preserved at $4^{\circ}C$ for 28 days demonstrated that the preparation with 0.4% $CaCl_2$ ranked highest in taste, hardness and overall acceptability. It wass suggested that supplementation with 0.4% $CaCl_2$ would be most appropriate to improve the textural properties of pickled radish wrap while maintaining its organoleptic quality.

Gastrointestinal Stromal Tumor (GIST) of the Stomach: Clinicopathologic Analysis and Outcome (위에 발생한 위장관 간질성 종양의 임상병리학적 특성과 치료성적)

  • Ryu Je-Seock;Lee Sung-Ryul;Choi Sae-Byeol;Park Sung-Soo;Lee Ju-Han;Kim Seung-Joo;Kim Chong-Suk;Chae Yang-Seok;Mok Young-Jae
    • Journal of Gastric Cancer
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    • v.5 no.1
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    • pp.40-46
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    • 2005
  • Purpose: Gastrointestinal stromal tumors (GISTs) are mesenchymal neoplasms of the gastrointestinal tract. GISTs are positive for the expression of c-Kit protein at immunohistochemistry, and their clinical presentations vary. This retrospective study was performed to evaluate the clincopathologic characteristics of GISTs and to define the prognostic factors. Materials and Methods: 40 patients who underwent a complete resection of a GIST during the period $1996\~2003$ at the Department of Surgery, Korea University College of Medicine, were studied. We divided them into low- and high-risk. groups by using tumor size and mitotic count: 23 cases were low risk, and 17 were high risk. Clinicopathologic features, immunohistochemical findings, and prognoses were compared between the low- and the high-risk groups. Results: The mean age of the 40 patients was $61.3\pm11.1$years, and the male-to-female ratio was 1:1.1. There was no significant difference in age and sex between the groups. A comparative analysis revealed tumor size, mitotic count, clinical symptoms, preoperative pathologic diagnosis, ulceration, and necrosis to be variables that had statistically significant differences between the high- and the low-risk groups. In the univariate analysis, tumor size, mitotic count, ulceration, necrosis, and abnormal endoscopic ultrasound findings were associated with disease-free survival, but in the multivariate analysis, mitotic activity was the only independent factor associated with disease-free survival. 8 patients had recurrences during the follow-up period, and four of them were treated with STI-571 (imatinib mesylate, $Gleevec^{(R)}$). The treated patients have survived until now; however, two of non-treated patients died from disease progression. Conclusion: Based on this study, tumor size, ulceration, and necrosis are significant factors affecting survival, and mitotic activity may be a useful prognostic marker. STI-571 may be used in an adjuvant setting because the drug has shown anticancer activity in patients with recurrence or metastasis.

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Antioxidant Compounds and Antioxidant Activities of Sweet Potatoes with Cultivated Conditions (재배조건에 따른 고구마의 항산화성분 및 항산화활성)

  • Woo, Koan-Sik;Seo, Hye-In;Lee, Yong-Hwan;Kim, Hyun-Young;Ko, Jee-Yeon;Song, Seuk-Bo;Lee, Jae-Saeng;Jung, Ki-Yuol;Nam, Min-Hee;Oh, In-Seok;Jeong, Heon-Sang
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.41 no.4
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    • pp.519-525
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    • 2012
  • Effects of cultivated conditions on antioxidant compounds and antioxidant activities of sweet potatoes (Ipomoea batatas (L.) Lam) were determined. The cultivated variety was Shinyulmi, and they were cultivated in a conventional culture, successful cropped hairy vetch culture, successful cropped barley cultivation, successful cropped rye cultivation, successful cropped mix-seeding of hairy vetch and barley, successful cropped mix-seeding of hairy vetch and rye, and not fertilizer. The brix degree, moisture, protein, and ash content of the sweet potatoes did not significantly change with the cultivated conditions. However amylose, total dietary fiber, and mineral content had significant changes. The total polyphenol, flavonoid, and tannin content of the methanolic extracts of the sweet potato's pericarp showed significant differences from cultivated conditions, however, the sweet potato's sarcocarp did not significantly change. The highest DPPH and ABTS radical scavenging activities of the methanolic extracts of the sweet potatoes were 958.81 and 663.53 mg TE/100 g in the sweet potato's pericarp on the successful cropped hairy vetch culture. Generally, there was a difference in antioxidant compound content and radical scavenging activity on the methanolic extract of sweet potato with cultivated conditions.

A Study on Applicable Level of Entrepreneurship: Focus on Entrepreneurial Orientation (기업가정신의 적용수준과 기업성과에 관한 연구 -기업가지향성을 중심으로-)

  • Han, Eun-Soo;Jeong, Beom-Goo;Lee, Sang-Bin;Sung, Eul-Hyun
    • Management & Information Systems Review
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    • v.36 no.2
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    • pp.157-185
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    • 2017
  • This study was carried out with the attention that the concept of entrepreneurial orientation has been applied at various levels of CEO, employee, management, and organization as a whole. The differences between these concepts were examined by discriminant validity and convergence validity, and the causal relationship between these concepts and performance was analyzed. A total of 96 questionnaires were collected and analyzed. The results show that CEO's entrepreneurial orientation, employee's entrepreneurial orientation, manager's entrepreneurial orientation and organizational entrepreneurial orientation have convergent validity and discriminant validity, and that these variables have different effects on the firm 's innovation performance and financial performance. In the analysis of the mediating effect, when the variables of all levels were put into a single variable, the innovation performance mediates between the entrepreneurial orientation and the financial performance in all variables. However, when all variables are applied simultaneously, innovation performance has mediating effect only on the relationship between organizational entrepreneurship orientation and financial performance. This shows that there is a conceptual difference according to applied level. As a result of the analysis of the causal relationship by the application level of entrepreneurial orientation, it is found that causality is formed among the entrepreneurial orientation variables. In particular, CEO's entrepreneurial orientation influences employee's entrepreneurial orientation, manager's entrepreneurial orientation, and organization's entrepreneurial orientation, and again, employee's entrepreneurial orientation and managerial entrepreneurial orientation form a causal relationship that influences organization's entrepreneurial orientation. In the relationship between innovation performance and financial performance, CEO's entrepreneurial orientation, organization's entrepreneurial orientation, and manager's entrepreneurial orientation are influencing innovation performance, and the only variables influencing financial performance are organization's entrepreneurial orientation. In conclusion, the limitations of the study and its future direction are presented.

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Comparison of Anisotropic Analytic Algorithm Plan and Acuros XB Plan for Lung Stereotactic Ablative Radiotherapy Using Flattening Filter-Free Beams (비편평화여과기 빔을 이용한 폐 정위절제방사선치료를 위한 AAA와 Acuros XB 계산 알고리즘의 치료계획 비교)

  • Chung, Jin-Beom;Eom, Keun-Yong;Kim, In-Ah;Kim, Jae-Sung;Lee, Jeong-Woo;Hong, Semie;Kim, Yon-Lae;Park, Byung-Moon;Kang, Sang-Won;Suh, Tae-Suk
    • Progress in Medical Physics
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    • v.25 no.4
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    • pp.210-217
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    • 2014
  • This study investigated the dosimetric effects of different dose calculation algorithm for lung stereotactic ablative radiotherapy (SABR) using flattening filter-free (FFF) beams. A total of 10 patients with lung cancer who were treated with SABR were evaluated. All treatment plans were created using an Acuros XB (AXB) of an Eclipse treatment planning system. An additional plans for comparison of different alagorithm recalcuated with anisotropic analytic algorithm (AAA) algorithm. To address both algorithms, the cumulative dose-volume histogram (DVH) was analyzed for the planning target volume (PTV) and organs at risk (OARs). Technical parameters, such as the computation times and total monitor units (MUs), were also evaluated. A comparison analysis of DVHs from these plans revealed the PTV for AXB estimated a higher maximum dose (5.2%) and lower minimum dose (4.2%) than that of the AAA. The highest dose difference observed 7.06% for the PTV $V_{105%}$. The maximum dose to the lung was also slightly larger in the AXB plans. The percentate volumes of the ipsilateral lung ($V_5$, $V_{10}$, $V_{20}$) receiving 5, 10, and 20 Gy were also larger in AXB plans than for AAA plans. However, these parameters were comparable between both AAA and AXB plans for the contralateral lung. The differences of the maximum dose for the spinal cord and heart were also small. The computation time of AXB plans was 13.7% shorter than that of AAA plans. The average MUs were 3.47% larger for AXB plans than for AAA plans. The results of this study suggest that AXB algorithm can provide advantages such as accurate dose calculations and reduced computation time in lung SABR plan using FFF beams, especially for volumetric modulated arc therapy technique.