In vitro quantification of occlusal caries lesion using QLF-D, ICDAS, and DIAGNOdent

Objectives : To compare the QLF-D method and the ICDAS and DIAGNOdent techniques for in vitro quantification of occlusal caries and to assess the histological features of the caries. Methods : One hundred and twenty-two extracted permanent teeth were selected, and the site of interest on the occlusal surface was examined using each detection method. The occlusal sites were classified according to the ICDAS II criteria based on the decision taken by two investigators, who have taken the ICDAS E-learning course. The examined site was then measured using the DIAGNOdent, and the peak value was recorded. In addition, by using the QLF-D, the occlusal site was photographed to obtain the ΔFmax value. After all assessments were performed, the occlusal sites were vertically sectioned in order to assess the histological features. This was considered the gold standard. The histological criteria were graded using a 4-point scale as follows: S=sound (n=21), E1=limited enamel caries (n=27), E2=caries extending to the dento-enamel junction (n=49), D=caries involving the dentine (n=25). Results : An ICDAS code between 0 and 4 was assigned to all the occlusal sites, and this revealed the QLF-D value, which was between -95 to 0. The DIAGNOdent value was between 8 and 99. The correlation values of QLF-D, ICDAS, and DIAGNOdent with the histological features were 0.68, 0.58, and 0.46, respectively (P<0.01). A highly significant correlation was observed between QLF-D and the gold standard, which showed a moderate correlation and an acceptable correlation was observed with ICDAS (r=0.75, P<0.01). A statistically significant difference was observed in the average QLF-D values of each histological grade i.e., -28.5 (S), -53.7 (E1), -68.1 (E2), and -84.4 (D). Conclusions : The QLF-D showed a significant correlation with the ICDAS and histological features. Therefore, visual inspection with QLF-D would improve the detection accuracy and ensure early diagnosis of dental caries.ope

The antimicrobial and anti-plaque effect of dentifrice containing baking soda and triclosan

Objectives. The aim of this study was to evaluate the antimicrobial and anti-plaque effect of dentifrice containing 24% baking soda and 0.3% triclosan in vitro and in clinical trial. Methods. This study was composed of two parts. The first part evaluated in vitro antibacterial effect of dentifrices containing baking soda or baking soda with triclosan by minimum inhibition concentration (MIC) of alamar blue staining. The second part was to evaluate anti-plaque effects by a randomized, double-blind clinical study. A total of 73 subjects were enrolled in this study, and they were all healthy adult volunteers who provided informed consent. They were divided into three groups, which were the baking soda group (dentifrice containing 24% baking soda), the baking soda/triclosan group (dentifrice containing 24% baking soda and 0.3% triclosan) and the control group. All groups were instructed to perform tooth brushing more than two times per day and not use the other oral hygiene products. The plaque was measured by Turesky modification of Quigley-Hein index in the six representative teeth. All subjects were evaluated at baseline, four weeks and eight weeks. Results. According to the antimicrobial effect observed in the in vitro study, the baking soda with triclosan dentifrices group showed the lowest level of MIC to S. mutans (0.04%) and P. gingivalis (0.04%) compared to the control and other test groups. According to the effect of reducing plaque formation in clinical study, the baking soda/triclosan and the baking soda dentifrice groups showed significant reduction of plaque formation at four weeks (p＜0.05), and additional reduction of plaque formation eight week laters (p＜0.05). Conclusions. The dentifrice containing 24% of baking soda and 0.3% of triclosan showed more antibacterial and anti-plaque effects than the control or baking soda group by in vitro study and clinical trial.ope

Analysis of the erosive effects of children’s beverages using a pH-cycling model

Objectives The aims of this in vitro study were (1) to assess the erosive potential of several children's beverages in comparison to cola and orange juice, by using an in vitro pH-cycling model, and (2) to investigate the factors related to dental erosion caused by the beverages. Methods Eight different children's beverages (Chorongi, Capri-sun, Grateful nature wisdom, I-kicker, Koal-koal koala, My friend pororo, Qoo, and Strong zzanggu), Cola, and an orange juice, which are available in the Korean market, were used. To characterize each test beverage, the pH, titratable acidity to pH 7.0, concentration of calcium and phosphorus, and degree of saturation with respect to hydroxyapatite (DSHAP) were analyzed. Erosive potential of the test beverages was assessed by the depth of enamel loss observed in specimens subjected to pH cycling for 8 days. This cycle consisted of exposure to each beverage for 20 min, thrice daily, and to a remineralizing solution every day. The correlation between the depth of the enamel loss and the chemical properties of the beverages was assessed by Spearman's rank correlation coefficients and multiple linear regression tests (P<0.05). Results The depth of enamel loss caused by the beverages was found to vary from 0.11 to 105.47 µm. Enamel loss with all the children's beverages tested was lesser compared to that with Cola (P<0.05) but was similar or greater than that with orange juice, except in one beverage. The pH, concentration of calcium, and DSHAP were significantly correlated with the depth of enamel loss (ρ=-0.842, ρ=-0.796, and ρ=-0.867, respectively; P<0.01). Multiple regression analysis showed that pH and concentration of calcium were impact variables for the erosive potential of test beverages (P<0.05). Conclusions The children's beverages tested had lower erosive potential than Coca Cola, but five (I-kiker, Grateful nature wisdom, Qoo, Capri-sun, and Chorongi) of them had higher erosive potential than orange juice. Moreover, among the chemical properties of beverages, significant factors affecting enamel loss were pH value and concentration of calcium.ope

Modification of surface pretreatment of white spot lesions to improve the safety and efficacy of resin infiltration

OBJECTIVE: A low-viscosity resin (infiltrant) was used to inhibit the progression of white spot lesions (WSLs) and resolve associated esthetic issues. An alternative pretreatment was explored to increase the pore volume of the surface layer of the WSLs. Also, the penetration effects of the infiltrant were evaluated for various pretreatments. METHODS: Sixty two artificial lesions were fabricated on bovine teeth. As a positive control, 15% HCl gel was applied for 120 seconds. Further, 37% H3PO4 gel was applied for 30 seconds using three methods. The samples were divided as follows: H3PO4 only group, H3PO4 sponge group, and H3PO4 brush group. The acid was gently rubbed with the applicators (i.e., a sponge or brush) throughout the application time. To compare the effects of resin infiltration, twenty paired halves of specimens were treated with an infiltrant (ICON®). RESULTS: Thicknesses of the removed surface layers and infiltrated areas were evaluated by confocal laser scanning microscope. The positive control and the 37% H3PO4 brush group failed to show significant differences in the removed thickness (p > 0.05); however, the mean percentage of the infiltrated area was higher in the 37% H3PO4 brush group (84.13 ± 7.58%) than the positive control (63.51 ± 7.62%, p < 0.001). Scanning electron microscope observations indicate higher pore volumes for the 37% H3PO4 brush group than for the positive control. CONCLUSIONS: Application of 37% H3PO4 with a brush for 30 seconds increased the pore volume of WSL surface layers and the percentage of infiltrated areas in comparison to the use of 15% HCl for 120 seconds.ope

Effects of Resveratrol on Reactive Oxygen Species-mediated Platelet Activation

혈소판은 지혈작용, 혈전형성 및 다양한 혈관 질환에서 중요한 역할을 한다. 혈소판이 활성화되면 활성산소종 (ROS, reactive oxygen species)의 생성이 증가되고, 생성된 ROS는 혈소판의 활성화를 촉진시키는 작용을 한다. Resveratrol (RV; 3,4&amp;apos;,5-trihydroxystilbene)은 항혈소판과 항산화 효과를 나타내며, RV에 의해서 혈소판의 응집과 ROS의 생성이 억제된다는 보고가 있다. 이런 결과들을 볼 때, RV의 항혈소판 효과는 ROS에 의한 혈소판의 활성화 증폭작용을 억제하기 때문에 나타나는 것으로 생각된다. 그러나, RV와 관련되어 ROS의 조절을 받는 특정 인자 및 이와 관련된 혈소판의 신호전달기전이 아직까지 명백히 밝혀진 바가 없다. 본 연구에서는 혈소판이 활성화될 때 생성이 증가되는 ROS에 의해 매개되는 신호전달기전을 RV가 항산화 효과를 통해 억제시키는 기전에 대하여 밝혀보았다. 이전에 알려진 바와 같이 RV는 collagen에 의해 활성화된 혈소판의 응집 및 ROS 생성을 억제하였다. Protein tyrosine phosphatase (PTP)의 일종인 Src homology region 2-containing protein tyrosine phosphatase-2 (SHP-2)는 ROS에 의해 산화되는 cysteine 잔기를 효소활성부위에 가지고 있다. SHP-2의 cysteine 잔기의 산화를 탐지할 수 있는 PEO-iodoacetyl biotin labeling 방법을 이용하여, collagen에 의해 생성이 증가된 ROS에 의한 SHP-2의 cysteine 잔기의 산화가 RV에 의해서 억제되는 것을 확인하였다. 또한, collagen 자극에 의해 나타나는 Vav1, Bruton’s tyrosine kinase (Btk), Phospholipase Cγ2 (PLCγ2)의 특정한 tyrosine 잔기의 인산화도 RV에 의해 감소되는 것을 확인하였다. 혈소판이 활성화될 때, PLCγ2의 downstream signal로 잘 알려진 세포질 내 칼슘 level의 증가와 혈소판의 표면에 존재하는 integrin αIIbβ3의 활성화도 RV에 의해 억제되었다. 이상의 결과들을 종합해 볼 때, 혈소판이 활성화 될 때 생성이 증가되는 ROS에 의해 SHP-2의 활성부위에 존재하는 cysteine이 산화되어 활성이 저하되는 것을 RV가 항산화작용을 통해 방지함으로써 phosphatase 활성이 유지되도록 함으로써 혈소판의 활성화를 억제하는 것으로 생각된다.;Platelets participate in thrombus formation, hemostasis and various vascular diseases. It has been demonstrated that platelet activation is associated with reactive oxygen species (ROS) production which promotes platelet activation. Previous studies have reported that resveratrol (RV; 3,4&amp;apos;,5-trihydroxystilbene) has antiplatelet and antioxidant properties. In this study we observed that collagen-induced aggregation and an increase in intracellular ROS were inhibited by RV. Although it seems that the antiplatelet property of RV is associated with an inhibition of ROS-mediated signaling pathways, the relationship between RV and a direct target of ROS in platelet activation has not been clearly defined. We therefore studied whether RV affects a specific target of ROS and its downstream signaling cascades in collagen-stimulated platelets. One of the redox-sensitive signaling molecules is the family of protein tyrosine phosphatases (PTPs), which contain catalytic cysteine residue vulnerable to ROS-mediated oxidation. It has been known that SH2 domain-containing tyrosine phosphatase-2 (SHP-2) is an important PTP in platelet activation. We observed that the catalytic cysteine residue of SHP-2 was oxidized and this oxidation was significantly inhibited by RV treatment in collagen-stimulated platelets. Simultaneously, the specific tyrosine phosphorylation of various key signaling molecules including Vav1, Bruton’s tyrosine kinase, phospholipase Cγ2 was decreased by RV, potentially through the inhibition of ROS-mediated SHP-2 oxidation. RV also inhibited downstream responses such as an elevation of cytosolic calcium level and the integrin αIIbβ3 activation on the surface of platelets. In conclusion, this study suggests that the antiplatelet effect of RV is resulted from the inhibition of increase in ROS level, the attenuated oxidation or inactivation of SHP-2, and the subsequent downregulation of tyrosine phosphorylation-dependent signaling pathways.1. 서론 = 1 2. 재료 및 방법 = 6 2.1. 재료 = 6 2.2. 혈소판 분리 = 7 2.2.1. 사람의 washed platelet 조제 = 7 2.2.2. Rat의 washed platelet 조제 = 8 2.3. 혈소판 응집 측정 = 9 2.4. SDS-polyacrylamide 전기영동법 = 9 2.5. Immunoblot 분석 = 10 2.6. 세포 내 ROS level 측정 = 11 2.7. PEO-iodoacetyl biotin label을 이용한 SHP-2 thiol 산화 측정 = 11 2.8. 세포질 내의 Ca2+ 농도 측정 = 12 2.9. 세포 표면의 integrin αIIbβ3 활성화 측정 = 14 2.10. 통계처리 = 14 3. 결과 = 15 4. 고찰 = 31 5. 참고문헌 = 39 Abstract = 4

Synthesis, Characterization and Physicochemical Properties of Paclitaxel-Phosphazene Conjugates

파클리탁셀은 유방암, 자궁암, 결장암, 비소세포성 폐암 등 여러 암에 대한 높은 항암효과와 내성문제의 해결 측면에서 최근에 발견된 가장 획기적인 항암제이다. 그러나 탁솔은 수용액에 대한 용해도가 낮아 탁솔 주사 시 50%의 에탄올과 50%의 Cremophor EL (polyoxyethylated castor oil)을 섞은 부형제에 포집 시켜야 한다. 그런데 부형제로 쓰이는 Cremophor EL은 호흡곤란, 흉통, 빈맥, 부정맥, 저혈압 등의 심각한 부작용을 유발한다. 최근에 본 연구진은 생분해성을 띠며 온도에도 감응하고 자가 조립하여 마이셀을형성하는 양친매성 폴리포스파젠에 대한 보고를 하였다. 이러한 포스파젠의 성질은 마이셀안에 파클리탁셀을 물리적으로 로딩시키거나 올리고 펩타이드의 곁가지에 파클리탁셀을 화학적 결합을 시킴으로써 얻을 수 있음을 확인하였다. 효능은 입증되었으나 물에 잘 녹지 않는 파클리탁셀을 이용해 포스파젠 유도체의 α-amine에 2’-succinyl paclitaxle을 컨쥬게이션켜 최종 합성시킨 싸이클로트라이포스파젠-파클리탁셀 컨쥬게이트는 수용액 상에서 자가 조립하여 마이셀을 형성하며 그 크기가 38.2 nm정도 되며 임계 마이셀 농도(CMC)가 체내에 주사하기 적당한 10 mg/L 임을 확인했다. 또 파클리탁셀 컨쥬게이트는 기존 프리 파클리탁셀에 비해 in vitro상에서의 세포독성 실험에서 예상대로 낮은 값을 보였다. 폴리포스파젠-파클리탁셀 컨쥬게이트 또한 폴리포스파젠 유도체의 α-amine에 2’-succinyl paclitaxel을 컨쥬게이션시켜 합성하였다. 이것 또한 수용액 상에서 자가 조립하여 마이셀을 형성하며 치환체의 분자량에 따라 마이셀의 크기가 10~20 nm정도 되며 임계 마이셀 농도(CMC)가 40~50 mg/L 임을 확인했다. 나노 크기의 50,000~70,000의 분자량을 갖는 폴리포스파젠-파클리탁셀 컨쥬게이트는 enhanced permeability and retention (EPR)효과에 의한 암 선택성을 가지고 있다. 이는 조직 내 분포 실험(biodistribution)을 통해 실험 시작 후 24시간 뒤에 일반조직에 대한 암 조직의 선택성 tumor to tissue ratio (TTR)의 값이 3.49임을 통해 확인할 수 있었다.;Paclitaxel is one of the most important antitumor agents currently in clinical use, since it exhibits effective antitumor activity against various cancers, such as breast, ovarian, and non-small cell lung cancers. However, its clinical applications are limited due to its extremely low water solubility (&amp;lt; 1 μg/ml)3 and serious side effects including hypersensitivity and neurotoxicity attributed to its formulating agent, Cremophore EL. Therefore, a great deal of efforts has been made to overcome such problems. Recently, we have reported a new type of thermoresponsive micelles self-assembled from amphiphilic phosphazenes grafted with hydrophilic poly(ethylene glycol) and hydrophobic oligopeptide. We have found that these phosphazene are useful for solubilization of paclitaxel by either physical micellar encapsulation or chemical conjugation to the oligopeptide side group of the phosphazene. A novel water-soluble and biodegradable cyclotriphosphazene-paclitaxel conjugate was prepared by reacting 2’-succinyl paclitaxel with cyclotriphosphazenes bearing equimolar glycyl-L-lysine and methoxy poly(ethylene glycol) as side groups. The macromolecular conjugate was found to self-assemble in aqueous solution to form stable micelles with a mean hydrodynamic diameter of 38.2 nm and a low critical micelle concentration of 10 mg/L. The present conjugate exhibited lower than free paclitaxel but reasonably high in vitro cytotoxicity against selected human tumor cells due to their hydrolytic degradation in PBS solution. The polyphosphazene-paclitaxel conjugate was also prepared by reacting 2’-succinyl paclitaxel with polyphosphazenes bearing glycyl-L-lysine and methoxy poly(ethylene glycol) as side groups. It was found to self-assemble in aqueous solution to form stable micelles with a mean hydrodynamic diameter of 10~20 nm and a low critical micelle concentration of 40~50 mg/L depending on the molecular size. Nanosized polyphosphazene-paclitaxel conjugate with a wide range of molecular weight from 50,000~70,000 were synthesized to study their tumor selectivity by enhanced permeability and retention (EPR) effect. It has been found from biodistribution study that the present polyphosphazene-paclitaxel conjugate exhibit high tumor selectivity by EPR effect with the tumor to tissue ratio (TTR) of 3.49 at 24hr.Chapter 1 Introduction = 1 1.1. Polymeric drug delivery systems = 2 1.2. Controlled drug release = 3 1.3. Biodegradable polymers = 4 1.4. Polyphosphazene = 6 1.4.1. Introduction = 6 1.4.2. Synthesis = 8 1.4.3. Physical properties = 11 1.4.3.1. Cyclophosphazene의 열개환중합반응 (Ring opening polymerization) = 11 1.4.3.2. 주사슬의 유연성 = 13 1.5. Paclitaxel as an anticancer agent = 15 1.5.1. History of the development of paclitaxel = 15 1.5.2. The mechanism of paclitaxel &amp;apos;s activity = 16 1.5.3. Toxicity and side-effects = 19 1.5.4. Structure activity relationships (SAR) of paclitaxel analogs = 19 1.6. EPR (enhanced permeability and retention) effect = 21 Reference = 23 Chapter 2 Synthesis and Characterization of Cyclotriphosphazene-Paclitaxel Conjugates = 27 2.1 Introduction = 28 2.2. Experimental section = 30 2.2.1. Materials = 30 2.2.2. Instruments = 31 2.2.3. Synthesis and characterization = 31 (가) HCl Gly-CbzLysine methylester의 합성 = 31 (1) Boc-Lys(Z)-OCH₃의 합성 = 31 (2) Lys(Z)-OCH₃의 합성 = 32 (3) BocGlyLys(Z)-OCH₃ 의 합성 = 33 (4) HCl·GlyLys(Z)-OCH₃ 의 합성 = 33 (나) [NP(MPEG550)GlyLysMe]3 의 합성 = 34 (다) 2&amp;apos;-Succinyl paclitaxel = 35 (라) {[NP(MPEG550)(GlyLysMe-2’-succinylpaclitaxel]₁ [NP(MPEG550)(GlyLys Me)]₂} 의 합성 = 36 (마) {[NP(MPEG550)(GlyLysMe-2’succinylpaclitaxel]₁[NP(MPEG550)(GlyLys Me)[NPMPEG550)(GlyLysMe)-Cy5.5]₁} 의 합성 = 37 2.2.4. Micelle size and size distribution = 37 2.2.5. Determination of critical micelle concentration = 37 2.2.6. In vitro cytotoxicity data = 38 2.2.7. In vivo xenograft trials against Hela cell lines = 39 2.2.8. Tissue distribution and tumor accumulation of trimer-paclitaxel conjugate = 39 2.2.9. Non-invasive NIR fluorescence image of trimer-paclitaxel conjugate = 40 2.3. Result and discussion = 41 2.3.1. Synthesis and characterization = 41 2.3.2. Critical micelle concentration (CMC) = 45 2.3.3. Size distribution = 46 2.3.4. In vitro cytotoxicity data = 47 2.3.5. In vivo xenograft experiment = 48 2.3.6. Organ distribution of the trimer-paclitaxel conjugate = 50 2.3.7. Tumor accumulation of the trimer-paclitaxel conjugate = 53 2.4. Conclusions = 55 Reference = 56 Chapter 3 Synthesis and Characterization of Polyphosphazene-Paclitaxel Conjugate = 59 3.1 Introduction = 60 3.2. Experimental Section = 62 3.2.1. Materials = 62 3.2.2. Instruments = 63 3.2.3. Synthesis and characterization = 63 (가) GlyLys(Boc)-OCH₂CH₃ 의 합성 = 63 (1) Z-Lys(Boc)-OCH₂CH₃의 합성 = 64 (2) Lys(Boc)-OCH₂CH₃의 합성 = 64 (3) CbzGlyLys(Boc)-OCH₂CH₃ 의 합성 = 64 (4) GlyLys(Boc)-OCH₂CH₃ 의 합성 = 65 (나) [NP(MPEG550)1.5(GlyLysEt)0.5]n 의 합성 = 66 (다) [NP(MPEG550)1.5(GlyLysEt)0.25 (GlyLysEt-2’-succinylpaclitaxel)0.25]n의 합성 (1) = 67 (라) [NP(MPEG550)1.5(GlyLysEt-2’-succinylpaclitaxel)0.5]n의 합성(2) = 68 (마) [NP(MPEG550)1.5(GlyLysEt)-Cy5.5)0.25(GlyLysEt-2’-succinylpaclitaxel)0.25]n 의 합성 = 69 3.2.4. Micelle size and size distribution = 69 3.2.5. Determination of critical micelle concentration = 69 3.2.6. In vitro degradation of polymer backbone = 70 3.2.7. In vitro cytotoxicity data = 70 3.2.8. Tissue distribution and tumor accumulation of polymer-paclitaxel conjugate = 71 3.2.9. Non-invasive NIR fluorescence image of polymer-paclitaxel conjugate = 71 3.3. Result and discussion = 72 3.3.1. Synthesis and characterization = 72 3.3.2. Critical micelle concentration (CMC) = 75 3.3.3. Size distribution = 77 3.3.4. In vitro degradation of polymer backbone = 79 3.3.5. In vitro cytotoxicity data = 80 3.3.6. Organ distribution of the polymer-paclitaxel conjugate = 81 3.3.7. Tumor accumulation of the polymer-paclitaxel conjugate = 83 3.4. Conclusion = 85 Reference = 86 Abstract = 8

The Effects of Group Bibliotherapy Program on Peer Relationships and Class Cohesion of the upper Grade Students in Elementary Schools

본 연구의 목적은 초등학교 고학년 학생들을 대상으로 한 학급단위의 집단독서치료가 초등학생의 또래관계와 학급응집력 향상에 미치는 효과를 알아보고 이를 바탕으로 집단독서치료를 창의적 체험활동의 교육과정으로 운영함으로써 학급단위 인성교육 차원에서 활용하려는데 목적이 있다. 연구 대상은 경기도 소재 D초등학교 5학년 2개 학급(학급당 학생 수 22명)을 선택하여 한 학급을 실험집단으로, 다른 학급을 비교집단으로 구성하여 실험집단에 10회기의 집단독서치료를 실시하였다. 집단독서치료 프로그램은 창의적 체험활동 시간을 이용하여 매 회기마다 50분씩 실시하였다. 같은 기간 비교집단에는 한자교육과 같은 또래관계와 학급응집력과는 관련 없는 활동 내용을 지도하였다. 본 연구는 유사실험설계로 아동의 또래관계와 학급응집력을 알아보기 위해 치료 전과 치료 후 각각 실험집단과 비교집단에 또래관계 검사, 학급응집력 검사를 실시하여 측정하였다. 본 연구의 가설을 통계적인 방법으로 검증하기 위해 SPSS/PC 18.0 프로그램을 사용하여 독립검정 t-test로 집단 간 동질성 검증을 하였다. 또, 일변량분석으로 두 집단 간 종속변인의 각 하위요인들이 사후점수 차이가 나는지 살펴보았으며 집단독서치료 프로그램의 순수한 실험효과를 검증하기 위해 공분산분석(ANCOVA)를 실시하였다. 본 연구에서 나타난 연구결과는 다음과 같다. 첫째, 집단독서치료 프로그램에 참여한 실험집단은 비교집단에 비하여 또래관계가 향상되었으며, 또래관계의 하위 요인 중 사회적 지지와 우의 영역이 유의미하게 향상되었다. 둘째, 집단독서치료 프로그램에 참여한 실험집단은 비교집단에 비하여 학급응집력이 향상되었으며, 학급응집력의 모든 하위 요인(환경 분위기, 상호신뢰, 사기, 일체감, 의사소통)이 유의미하게 향상되었다. 뿐만 아니라 활동 회기별로 작성한 아동의 활동 소감을 분석한 결과, 서로 친밀감이 생기고 기본적인 대화법을 알게 되어 도움이 되었다는 반응과 서로를 의지하고 응원하는 모습을 보여 집단독서치료 프로그램이 또래관계와 학급응집력에 효과가 있음을 보완해주었다. 본 연구의 제한점은 다음과 같다. 우선, 본 연구에서 유의미한 효과가 나오지 않은 또래관계의 ‘처벌주도권’과 ‘대립’영역을 위한 활동들이 본 프로그램에서 다른 영역들에 비해 충분히 다루어지지 않았다는 한계점이 있어 이를 보완한 프로그램이 추후 구성되어 연구될 필요성이 있다. 또한 경기도 G시에 재학 중인 초등학교 5학년 한 학급만을 대상으로 실시한 연구이므로 연구결과를 일반화하기에는 부족하다. 그리고 학급 전체 아동을 대상으로 프로그램을 진행하다보니 아동들의 상호작용 및 행동변화를 상세히 관찰․분석하는데 어려움이 있었으며 10회기의 단기간 프로그램으로 근본적인 변화를 위한 지속적인 프로그램으로 보기엔 한계가 있다.;The purpose of this study is to apply the group Bibliotherapy as experiential learning activities to humanistic education in elementary curriculum among upper grade students. It focuses on the influence of group therapy in peer relationship and Class Cohesion. Selected subjects were two 5th grade classes with 22 students each from D elementary school located in Gyeong-gi province. One class, a experimental group, had 10 sessions of 50 minutes group Bibliotherapy, while comparative group had chinese character learning programs, which does not affect on peer relationship nor Class Cohesion. To prove the effects of the Bibliotherapy, preceeding and post peer relationship test and Class Cohesion test were conducted to both groups. The data were analyzed statistically through independent t-test with SPSS/PC 18.0 to verify correlations of two groups. Based on one-way ANOVA method, sub factors of dependent variable were reviewed for significant difference between pre and post test. In addition ANCOVA was used to verify authentic effect of the therapy. The results were as follows First, the experimental group’s peer relationship enhanced more significantly than comparative groups’ especially on group support and amity area. Second, the Class Cohesion within experimental group increased in class atmosphere, credibility, morale, unity, and communication. Each session reviews of the subjects showed the peer relationship and the Class Cohesion improved due to increase communication, support, dependency, and intimacy which proves effect of the group reading program. The limitation of the research is as follow : The program had minimal effects on sub factors such as punishment hegemony, and conflict relatively to other sub factors, which will require additional support program in future. Since the research only covered one class out of 5th graders in the school, it restrained the result to be generalized, in addition the limited number of sessions and qualitative observation. A short-term programs such as 10 or less sessions was hard to consider to cause fundamental changes.Ⅰ. 서론 1 A. 연구의 필요성 및 목적 1 B. 연구 가설 4 Ⅱ. 이론적 배경 5 A. 또래관계 5 B. 학급응집력 7 C. 독서치료 9 Ⅲ. 연구방법 17 A. 연구대상 17 B. 연구절차 17 C. 검사도구 18 D. 자료 분석 방법 21 Ⅳ. 연구 결과 23 A. 또래관계에 대한 독서치료프로그램의 효과성 23 B. 학급응집력에 대한 독서치료프로그램의 효과성 27 C. 또래관계와 학급응집력의 상관관계 31 D. 주관적 효과 평가 33 Ⅴ. 결론 및 논의 34 A. 요약 및 논의 34 B. 연구의 제한점 및 후속 연구를 위한 제언 36 참고문헌 38 부록 43 ABSTRACT 7

한의사 인력의 진료 생산성에 관한 연구 : 1차 의료기관을 중심으로

학위논문(석사)--서울대학교 보건대학원 :보건학과 보건경제학전공,2000.Maste

An Experimental Study on the Bed Combustion Phenomena in MSW(Municipal Solid Waste) Incinerator

Experimental studies have been performed to observe the basic phenomena of waste bed combustion in MSW incinerator. A reduced scale apparatus was utilized to simulate the combustion behavior in real plant with 1-dimensional transient behavior at the experimental setup, which uses wet cubic wood with ash content as simulated waste. LHV(lower heating value) of solid fuel, fuel particle size and flow rate of combustion air were taken as important parameters of the bed combustion. For the quantitative analysis, FPR(flame propagation rate), TBT(total burn-out time) and PBT(particle burn-out time) was defined. LHV represent the capability of heat release of the fuel, so that a higher LHV results in faster reaction rate of the fuel bed, which is shown by higher FPR. Fuel particle size is related with surface area per unit mass as well as heat and mass transfer coefficient. As the particle size increases the FPR decreases owing to decreasing specific surface area. Air injection supplies oxygen to the reaction zone. However oversupply of combustion air increases convection cooling of the bed and possibly extinguishes the flame

Prevention of dental erosion of a sports drink by nano-sized hydroxyapatite in situ study

AIM: To evaluate the inhibitory effects of the sports drink containing nano-sized hydroxyapatite (nano-HA) on dental erosion in situ. DESIGN: The study had a single-blind, two-treatment crossover design. The two treatment groups were a control group (CG; Powerade only) and an experimental group (EG; 0.25% wt/vol nano-HA was added to Powerade). Ten subjects wore removable palatal appliances containing bovine enamel specimens. The appliances were immersed in each drink for 10 mins, 4 times a day for 10 days. The tooth surface microhardness (SMH) was tested, and the erosion depth and the morphology of the tooth surface were observed. The data were analysed by repeated measures anova and t-test. RESULTS: Between the baseline and the 10th day, SMH was decreased by 80% in the specimens of the CG (P < 0.001), whereas there was only a 6% decrease in the SMH of the specimens in the EG. An erosion depth of 12.70 ± 4.66 μm and an irregular tooth surface were observed on the 10th day in the specimens of the CG. No dental erosions, however, was observed in the specimens of the EG. CONCLUSIONS: The sports drink containing 0.25% nano-HA was effective in preventing dental erosion in situ.ope