• Journal of Veterinary Clinics
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• v.20 no.3
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• pp.294-301
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• 2003

This study was performed to compare the effects of hydrocolloid(Duoderm$\circledR$, HC in this study) and hydrogel (Nu-Gel$\circledR$, HG in this study) occlusive dressing materials on degree of exudate, wound contraction, epithelialization, and healing of full-thickness skin wound in dogs. Three wounds measuring 2${\times}$2 cm in size were created bilaterally(6 wounds/dog) on the dorsolateral aspect of the trunk of 12 dogs. In each dog, the wounds were treated with HC, HG, and normal saline, respectively. For a 4 week period, the wounds were evaluated gross aspects and histopathological aspects. There were no statistically significant differences between treatment groups in percentage of wound contraction, percentage of epithelialization, and percentage of wound total healing during the first week. Significant differences were first detected on day 14. On day l4(P < 0.01) and 21 (P < 0.05), mean percentage of epithelialization of HG-treated wound was significantly greater than those in HC- and normal saline-treated wound. Mean percentage of wound contraction of HG-treated wound was significantly greater than that in HC- and control wounds on day 21(P< 0.05). On day 21, mean percentage of wound healing of HG-treated wound was significantly greater than that in HC- and control wounds(P < 0.02). On day 1, 4, and 7 after wound creation, although severe infiltration of PMN (polymorphonuclear leukocyte) cells in HC- and control wounds were observed in the subcutis and moderate infiltration of PMN cells in HG-treated wound were observed in the subcutis, we did not detect significant differences. On day 14 after wounding creation, in the wounds treated with HG dressing, epithelial cells were found over the surface, and edema further decreased in the tissue under the wounds, and the granulation tissue was replaced with collagen fibers. On day 21 after wound creation, in HG-treated wound compared with other experimental material-treated wounds, regenerated epidermis covered most of the wound surface, and the granulation tissue was more replaced with collagen fibers than that on day 14. Overall results indicated that the use of hydrogel dressing materials(Nu-Gel$\circledR$) as hydrocolloid dressing (Duoderm$\circledR$) materials and normal saline treatment on full-thickness skin wounds in dogs increased the rate of healing at repair stage.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.201-210
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• 2015

Purpose: In order to aggregate effect of the improvement of binocular vision function by vision therapy, total mean effect size, mean effect size by dependent variables, and effect size by characteristics of the subjects and characteristics of treatment were analyzed by meta-analysis. Methods: We analyzed data from 14 Korean National primary studies, which reported effects of vision therapy programs, using meta-analysis. Results: The effect size of total mean was 1.207, which showed high effect. The mean effect size according to the subcategory of the binocular dysfunctions was the highest for vergence dysfunctions group (2.989), followed by accommodative dysfunctions group (0.868) and group with both vergence dysfunctions and accommodative dysfunctions (0.692). The effect size according to the characteristics of the subjects was the highest in the vision therapy conducted in the binocular dysfunctions group (2.509) that had no other dysfunctions. The mean effect size according to the number of programs was the highest (2.310) for 7 times a week. Vision therapy for improving the binocular functions was the most effective (2.019) in 8 weeks later from vision therapy start. Conclusions: It can prove that the therapy for the improvement of binocular vision function is effective through that each result of the vision therapy effect is converted to mean effect size, and being objectifying the mean effect size.

• The Journal of the Korea Contents Association
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• v.16 no.1
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• pp.743-752
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• 2016

This study aims to investigate the overall effects of teaching grammar in the Korean EFL classroom. A meta-analysis of 67 research findings in 30 articles was conducted to synthesize the results of these studies by calculating the mean effect sizes. This study reviewed and analyzed the previous studies in terms of subjects, treatment period, and types of grammar teaching. The results showed that teaching grammar in the classroom had beneficial effects on learners in general (d=.907). It was found to be more effective for middle school and university students than for elementary and high school students (Q=37.065, df=3, p=.000). There was no statistically significant difference in terms of treatment period and types of grammar teaching. Pedagogical implications and suggestions for Korean EFL learners are also discussed.

• The Korean Journal of Applied Statistics
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• v.30 no.5
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• pp.615-632
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• 2017

Unlike randomized trial, statistical strategies for inferring the unbiased causal relationship are required in the observational studies. The matching with the propensity score is one of the most popular methods to control the confounders in order to evaluate the effect of the treatment on the outcome variable. Recently, new methods for the causal inference in latent class analysis (LCA) have been proposed to estimate the average causal effect (ACE) of the treatment on the latent discrete variable. They have focused on the application study for the real dataset to estimate the ACE in LCA. In practice, however, the true values of the ACE are not known, and it is difficult to evaluate the performance of the estimated the ACE. In this study, we propose a method to generate a synthetic data using the propensity score in the framework of LCA, where treatment and outcome variables are latent. We then propose a new method for estimating the ACE in LCA and evaluate its performance via simulation studies. Furthermore we present an empirical analysis based on data form the 'National Longitudinal Study of Adolescents Health,' where puberty as a latent treatment and substance use as a latent outcome variable.

• Journal of Veterinary Clinics
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• v.26 no.4
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• pp.324-330
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• 2009

This study was performed to determine the effectiveness of poloxamer/sodium alginate mixture(PX/SA) barriers on prevention of post-operative peritoneal adhesion in dogs. Fifteen mongrel dogs were divided into three experimental groups: non-treated group, 2% Sodium Carboxymethylcellulose (SCMC) treated group and PX/SA treated group. In order to induce adhesions, the anti-mesenteric serosa of the ileum was exteriorized and then abraded in a standard manner by scraping with a scalpel blade to create homogeneous petechial hemorrhagic surface over a 1 ${\times}$ 1 cm area. Solution of SCMC was allowed to spread across the intraperitoneal organs through a catheter using a syringe. PX/SA was simply coated over the abraded tissues. On day before and day 1, 4, 7, and 14 after operation, venous blood specimens were collected for measurement of RBC, total WBC and fibrinogen. The adhesions were blindly assessed 3 weeks later by using a computerized tensiometer. The RBC, total WBC and fibrinogen values of three groups showed no statistical significances. The mean tensile strength(gram force, gf) of formed adhesions on day 21 after surgery was 173.05${\pm}$113.48 in the non-treated group, 111.42 ${\pm}$ 38.25 in the SCMC group, and 69.00 ${\pm}$ 45.07 in the PX/SA group. The tensile strength values for adhesion seperation in PX/SA group was lower than those in SCMC group(p < 0.05) and significantly lower than those in the non-treated group(p < 0.05). Our data suggested that PX/SA should be effective on reducing peritoneal adhesion formation in dogs compared with SCMC. PX/SA may be applicable to preventing post-operative intraperitoneal adhesion in dogs.

• Journal of Chest Surgery
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• v.43 no.3
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• pp.235-245
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• 2010

Background: Our goal was to evaluate anti-calcification effects of decellularization and diverse fixing methods including preincubation of the bovine pericardium with ethanol. We also assessed changes in mechanical properties. Material and Method: Harvested bovine pericardium was decellularized with 0.25% sodim dodecysulfate and then treated with 5 methods of fixation: (1) 0.5% glutaraldehyde (GA) for 14 days, (2) 0.5% GA for 5 days, 2% GA for 2 days and 0.25% GA for 7 days, (3) 0.5% GA for 5 days, 2% GA for 2 days, 0.25% GA for 7 days, and then 70% ethanol for 2 days, (4) 0.5% GA for 5 days, a mixture of 2% GA and 70% ethanol for 2 days, and 0.25% GA for 7 days, (5) 0.5% GA for 5 days, a mixture of 2% GA, 65% ethanol, and 5% octanediol for 2 days and then 0.25% GA for 7 days. All treated bovine pericardia were tested for histological variables, lipid content, and mechanical properties including tensile strength and thermal stability. A total 10 kinds of differently treated bovine pericardia were implanted into rat subdermis and harvested 8 weeks later. Harvested pericardia were evaluated for calcium content. Result: No protein denaturation was observed microscopically after decellularization. There was a 32% mean decrease in tensile strength index after decellularization in the bovine pericardium group fixed. Octanediol preincubation attenuated the decrease in tensile strength and maintained thermal stability. TG and cholesterol were not affected by decellularization but were decreased by organic solvent. Calcium content was decreased after decellularization, and organic solvent preincubation decreased calcification in the non-decellularized bovine pericardium group. Conclusion: Decellularization and organic solvent preincubation have anti-calcification effects but decellularization may cause mechanical instability. A method of decellularization and fixation that does not cause damage to matrices will be needed for evaluation of the next step in using tissue-engineering for replacement of cardiac valves.

• Korean Journal of Veterinary Research
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• v.40 no.3
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• pp.635-643
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• 2000

The aim of this study was to determine the effectiveness of carboxymethyl chitosan(CMC) solution on preventing intraperitoneal adhesions. In this study, 44 rats were divided into four groups ; an untreated control group and three experimental groups that were treated with 3 ml of 1, 2 or 3% CMC solution, respectively. The anti-mesenteric serosa of the ileum was exteriorized and then abraded in a standard manner by scraping with a scalpel blade to create homogenous petechial hemorrhagic surface over a $0.5{\times}1cm$ area. The adhesions were blindly assessed 2 weeks later by using a computerized tensiometer. The mean tensile strength(Newton) of formed adhesions was $2.48{\pm}0.88$ in control group, $1.86{\pm}0.56$ in the 1% CMC-treated group, $1.75{\pm}0.71$ in the 2% CMC-treated group and $1.55{\pm}0.60$ in the 3% CMC-treated group. The most favorable prevention against adhesion was achieved in the 3% CMC-treated group(p<0.01). We could conclude that CMC was effective on preventing the formation of postoperative small intestinal adhesions in the rat.

• The Journal of the Korea Contents Association
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• v.18 no.10
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• pp.298-305
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• 2018

The objective of this present study was to investigate the overall effects of strategy instruction on Korean students' English language learning. In order to do so, 55 individual experimental results in 46 journal articles were collected, and a meta-analysis was carried out to them. This study also analyzed the results of studies on strategy instruction according to various variables such as school types, treatment periods, and types of dependent variable. The mean effect size of strategy instruction in English language teaching is .536, which means the medium effects in general. No statistically significant differences were found among various moderators and dependent variables. Based on these results, suggestions for further research are discussed.

• The Korean Journal of Applied Statistics
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• v.32 no.2
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• pp.173-185
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• 2019

Causal questions are prevalent in scientific research, for example, how effective a treatment was for preventing an infectious disease, how much a policy increased utility, or which advertisement would give the highest click rate for a given customer. Causal inference theory in statistics interprets those questions as inferring the effect of a given intervention (treatment or policy) in the data generating process. Causal inference has been used in medicine, public health, and economics; in addition, it has received recent attention as a tool for data-driven decision making processes. Many recent datasets are observational, rather than experimental, which makes the causal inference theory more complex. This review introduces key concepts and recent trends of statistical causal inference in observational studies. We first introduce the Neyman-Rubin's potential outcome framework to formularize from causal questions to average treatment effects as well as discuss popular methods to estimate treatment effects such as propensity score approaches and regression approaches. For recent trends, we briefly discuss (1) conditional (heterogeneous) treatment effects and machine learning-based approaches, (2) curse of dimensionality on the estimation of treatment effect and its remedies, and (3) Pearl's structural causal model to deal with more complex causal relationships and its connection to the Neyman-Rubin's potential outcome model.

• Radiation Oncology Journal
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• v.24 no.1
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• pp.67-76
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• 2006

Purpose: Oral mucositis is a common toxicity of radiation or chemotherapy, which is used a treatment for head and neck cancer. We investigated effects of recombinant human epidermal growth factor (rhEGF) on radiation-induced oral mucositis in rat model. Materials and Methods: Spraque-Dawley rats (7 per group) exposed to a single dose of 25 Gy (day 0) on their head, except for one group, were randomly divided into un-treated, vehicle-treated, and two rhEGF-treated groups. Rats were topically applied with rhEGF (15 or $30{\mu}g/oral$ cavity/day) or vehicle to their oral mucosa. Survival rate of rats, weight changes, and food intakes were examined from day 0 to 18 after radiation. Histology study was performed from oral mucosa of rats at day 7 and 18 after radiation. Results: rhEGF-treated groups (15 or $30{\mu}g/oral$) showed all survival rate 33%, whereas un-treated and vehicle-treated groups showed all survival rate 0% at the end of experiment. rhEGF-treated groups statistically had less weight loss compared to vehicle-treated group from day 2 to 7 after radiation. Food intake of rats with rhEGF treatment turned to increase at day 14 after radiation. At 7 day after radiation, un-treated and vehicle-treated groups showed severe pseudomembraneous or ulcerative oral mucositis. On the other hand, rhEGF-treated groups had no more than cellular swelling and degeneration of epidermal cells in oral mucosa of rats. Conclusion: These results suggest that rhEGF has significantly positive effects on radiation-induced oral mucositis in rats. rhEGF display a therapeutic potential on a clinical level.