• 한국강구조학회 논문집
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• 제15권3호
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• pp.291-298
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• 2003

최근 건축물의 대형화로 구조물의 기초는 비균질지반에 지지된다. 본 연구는 면내력을 받는 후판의 진동해석을 한 것이다. 장방 형판은 등방, 균질의 선형 탄성재료로 구성되었다. 장방형 후판의 진동해석은 8절점과 9절점을 이용한 장방형 유한요소를 사용하여 행하였다. 본 연구에서 기초를 수직스프링으로 이상화한 Winkler지반에 전단지반층을 추가한 Pasternk지반으로 이상화하였다. 지반의 강성을 달리한 비균질 Pasternak지반에 지지된 판을 해석하기 위해 중앙부분과 가장자리 부분의 Winkler지반계수를 WFP1과 WFP2로 선택하였다. (그림 4.) Winkler지반계수 WFP1과 WFP2는 0, 10, $10^2$, $10^3$으로 변환시키고 전단지반강성은 0, 5, 10으로 하였다. 후판의 좌굴응력(${\sigma}_{cr}$)에 대한 면내력의 비는 각각 0.4, 0.8에 대해 적용하였다.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2013년 춘계학술대회
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• pp.19-29
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• 2013

Slips and falls are associated with many occupational injuries in Korea. It is also estimated that slipping are major contributors to slip, trip and fall injury burden. So "LOCAL RULE ON OCCUPATIONAL SAFETY AND HEALTH STANDAR D" must be improved, especially article 3(prevention of slip, trip and fall). The primary purpose of the present study is to determine if, and to what extent, the standard could be improved in present environment. In order to fulfill our objective, the another regulation in Korea and foreign countries were investigated and reviewed. Many kind of standard, mandatory documents and guideline were also reviewed. And then, regulations, standard, guideline etc. reviewed were compared with each others. The article 3 was revised as below. 1. The floors of the traffic route in workplace shall have no hole or slope, or be uneven or slippery so as, in each case, to expose employees to slip, trip and fall risk, except if adequate measures have been taken to prevent a employees falling. 2. The employer shall design, install and fix the drain for effective drainage if fluid contaminants were frequently occurred. So far as is reasonably practicable, An employer shall keep the workplace clean, sanitary, and dry so that employees won't have any risk to tripping or slipping at the workplace. 3. To facilitate cleaning, every floor, workplace, and passageway shall be, so far as is reasonably practicable, kept free from protruding objects, splinters, holes, etc. Also, some criteria was developed in this study. Standard and criteria developed in this study will help to prevent slip, trip, and fall injuries.

• 한국동물학회지
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• 제31권1호
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• pp.21-28
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• 1988

dbcAMP에 의해 성숙이 억제된 생쥐난자의 수정능을 조사하기 위해 본 실험을 행하였다. dbcAMP로 일시 성숙이 억제되었던 난자를 배양액내에서 정자와 섞고 24시간 배양한 후 발생한 2세포기의 배아형성, 정자의 관입, 전액형성을 조사하여 2세포기로 배아발생이 진척된 것을 수정율의 기준으로 정하였다. dbcAMP를 처리하지 않은 난자는 약 53.3%의 수정율을 보였으며,dbcAMP가 함유되 배양액에서 배양한 후 기본 배양액에서 성숙시킨 난자들의 수정율은 dbcAMP의 처리시간에 비례하여 낮으나, 정자의 관입은 정상적으로 일어났다. 전자현미경적 관찰에 의하면 dbcAMP 처리는 난자의 미세구조에 어떠한 변화도 야기하지 않았다. 따라서 dbcAMP를 사전처리하여 성숙을 억제한 난자라할지라도 어느 정도의 수정능력을 보유하고 있다고 사료된다.

• 대한한의학회지
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• 제28권1호통권69호
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• pp.198-210
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• 2007

Objectives : Nitric oxide(NO) is a reactive free radical and a messenger molecule in many physiological functions. However, excessive release NO of induces neurotoxicity. We investigated whether a mixture of red ginseng and paeonia radix prossesses a protective effect against sodium nitroprusside(SNP)-induced apoptosis in the human neuroblastoma cell line SK-N-MC. Methods : We performed 3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay, 4,6-diamidino-2-phenylindole(DAPD) staining, terminal deoxynucleotidyl transferase(TdT)-mediated dUTP nick end labeling(TUNEL)assay, DNA fragmentation assay, reverse transcription-polymerase chain reaction(RT-PCR), Western blot analysis, and caspase-3 enzyme activity assay in SK-N-HFC cells. Result : MTT assay showed that SNP treatment significantly reduced the viabilities of cells and that pre-treatment with the red ginseng and paeonia radix mixture alleviated SNP-induced cytotoxicity. The cells treated with SNP exhibited several apoptotic features, while those pre-treated fir 1 h with the mixture of red ginseng and paeonia radix 1 h prior to SNP expose showed reduced apoptotic features. In addition, the cells pre-treated with the red ginseng and paeonia radix mixture for 1 h prior to SNP expose increased bel-2 expressions, decreased Bax expressions, and decreased caspase-3 enzyme activity. Conclusions : These results show that the red ginseng and paeonia radix mixture exerts a protective effect against SNP-induced apoptosis in SK-N-MC cells.

• KSBB Journal
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• 제26권5호
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• pp.386-392
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• 2011

Human cytotoxic T-lymphocyte antigen 4-immunoglobulin (hCTLA4Ig), an immunosuppressive agent, was expressed in transgenic rice cells using RAmy3D promoter and RAmy1A signal peptide for the inducible production and secretion into culture media by sugar depletion. In this study, sodium butyrate was used as a small molecular enhancer (SME) to enhance the production of hCTLA4Ig in transgenic rice cell suspension cultures. When 1 mM sodium butyrate was added in sugar-free media, relative viability was not reduced, while the productivity was improved 1.3-fold. In addition, by supplementing 87 mM sodium pyruvate as an alternative energy source during the production phase, death rate of the cells was decreased. When sodium pyruvate was not added, most cells became dead at day 6. However, by adding sodium pyruvate, 18% of viability can be maintained until day 10 and the production of hCTLA4Ig was enhanced 1.4-fold. When the combination of sodium pyruvate and sodium butyrate at optimum concentrations was added, the highest viability and hCTLA4Ig production could be obtained. The highest level of hCTLA4Ig reached up to 35 mg/L at day 10.

• Radiation Oncology Journal
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• 제35권4호
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• pp.332-339
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• 2017

Purpose: This study aimed to evaluate the prognostic effects of lymphovascular invasion (LVI) in triple-negative breast cancer (TNBC) patients who underwent surgical resection. Materials and Methods: A total of 63 non-metastatic TNBC patients who underwent surgical resection were retrospectively investigated from 2007 to 2016 in Inje University Busan Paik Hospital. Pathological tests revealed that 12 patients (19.0%) had LVI. Approximately 61.9% (n = 39) of the patients' samples stained positive for p53. Additional chemotherapy and radiotherapy (RT) were performed in 53 (84.1%) and 47 (74.6%) patients, respectively. Results: The median follow-up period was 39.5 months (range, 5.9 to 123.0 months). The pathological T stage (p = 0.008), N stage (p = 0.014), and p53 positivity (p = 0.044) were associated with LVI. Overall, the 3-year disease-free survival (DFS) rate and overall survival (OS) rate were 85.4% and 90.2%, respectively. Ten patients (15.9%) experienced relapse. LVI (n = 12) was associated with relapses (p = 0.016). p53 positivity was correlated with poor DFS (p = 0.048). Furthermore, LVI was related to poor DFS (p = 0.011) and OS (p = 0.001) and considered as an independent prognostic factor for DFS (p = 0.039). The 3-year DFS of patients with LVI (n = 12) was only 58.3%. Adjuvant RT minimized the negative prognostic effect of LVI on DFS (p = 0.068 [with RT] vs. p = 0.011 [without RT]). Conclusion: LVI was related to the detrimental effects of disease progression and survival of TNBC patients. Thus, a more effective treatment strategy is needed for TNBC patients with LVI.

• The Journal of Advanced Prosthodontics
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• 제11권5호
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• pp.262-270
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• 2019

PURPOSE. The purpose of this in vitro study was to evaluate the marginal misfits of three-unit frameworks fabricated with conventional and digital impressions techniques. MATERIALS AND METHODS. Thirty brass canine and second premolar abutment preparations were fabricated by using a computer numerical control machine and were randomly divided into 3 groups (n=10) as follows: conventional impression group (Group Ci), Cerec Omnicam (Group Cdi), and 3shape TRIOS-3 (Group Tdi) digital impression groups. The laser-sintered metal frameworks were designed and fabricated with conventional and digital impressions. The marginal adaptation was assessed with a stereomicroscope at ${\times}30$ magnification. The data were analyzed with 1-way analysis of variances (ANOVAs) and the independent simple t tests. RESULTS. A statistically significant difference was found between the frameworks fabricated by conventional methods and those fabricated by digital impression methods. Multiple comparison results revealed that the frameworks in Group Ci (average, $98.8{\pm}16.43{\mu}m$; canine, $93.59{\pm}16.82{\mu}m$; premolar, $104.10{\pm}15.02{\mu}m$) had larger marginal misfit values than those in Group Cdi (average, $63.78{\pm}14.05{\mu}m$; canine, $62.73{\pm}13.71{\mu}m$; premolar, $64.84{\pm}15.06{\mu}m$) and Group Tdi (average, $65.14{\pm}18.05{\mu}m$; canine, $70.64{\pm}19.02{\mu}m$; premolar, $59.64{\pm}16.10{\mu}m$) (P=.000 for average; P=.001 for canine; P<.001 for premolar). No statistical difference was found between the marginal misfits of canine and premolar abutment teeth within the same groups (P>.05). CONCLUSION. The three-unit frameworks fabricated with digital impression techniques showed better marginal fit compared to conventional impression techniques. All marginal misfit values were clinically acceptable.

• Journal of Ceramic Processing Research
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• 제13권spc2호
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• pp.341-345
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• 2012

[Li0.055(K0.5Na0.5)0.945](Nb1-xTax)O3 (0.05 ≤ x ≤ 0.25) ceramics were prepared by the partial sol-gel (PSG) method to improve the microstructure homogeneity of Ta5+ ion and were compared to those prepared by the conventional mixed oxide (CMO) method. For the PSG method, Ta(OC2H5)5 was directly reacted with calcined [Li0.055(K0.5Na0.5)0.945]NbO3 powders and the specimens sintered at 1100 ℃ for 5 hrs showed a single phase with a perovskite structure. Compared to the specimens prepared by conventional mixed oxide powders, the relative ratio of tetragonal phase to orthorhombic phase of the sintered specimens prepared by Ta(OC2H5)5 was larger than that of the sintered specimens prepared by Ta2O5. The electromechanical coupling factor (kp), piezoelectric constant (d33) and dielectric constant (εr) of the sintered specimens were increased with Ta5+ content. These results could be attributed to the decrease of the orthorhombic-tetragonal polymorphic phase transition temperature (To-t), which could be evaluated by oxygen octahedral distortion. Strain of the sintered specimens prepared by the PSG method was higher than that of specimens prepared by the CMO method due to the increase of relative density. The effects of crystal structure on the strain characteristics of the specimens were also discussed.

• Restorative Dentistry and Endodontics
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• 제45권4호
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• pp.47.1-47.11
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• 2020

Objectives: The aim of this study was to assess the physicochemical properties, cytotoxicity and penetration into dentinal tubules of ChlorCid^TM Surf (3% sodium hypochlorite [NaOCl] with surfactant) in comparison to ChlorCid^TM (3% NaOCl without surfactant). Materials and Methods: The physicochemical properties evaluated were pH, surface tension, free available chlorine (FAC) and contact angle. Cytotoxicity was evaluated in L929 fibroblasts exposed to the solutions by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and neutral red assays. Assessment of penetration into dentinal tubules was performed by staining single-rooted permanent human teeth with crystal violet (n = 9), which were irrigated with the solutions and analyzed in cervical, middle and apical segments. Data were analyzed by one-way analysis of variance (ANOVA) and Tukey's post-test, 2-way ANOVA and Bonferroni's post-test or t-test (α = 0.05). Results: ChlorCid^TM Surf and ChlorCid^TM FAC values were close to those indicated by the manufacturer. ChlorCid^TM Surf showed lower surface tension and contact angle on dentin, and higher pH than ChlorCid^TM (p < 0.05). The penetration of ChlorCid^TM Surf was higher in cervical and middle segments, compared with ChlorCid^TM (p < 0.05). There was no difference in irrigant cytotoxicity (p > 0.05). Conclusions: ChlorCid^TM Surf showed lower surface tension, lower contact angle on root canal dentin, higher penetration into dentinal tubules and more alkaline pH, compared with ChlorCid^TM. However, both solutions showed similar cytotoxicity and FAC content.

• 대한치과의료관리학회지
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• 제11권1호
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• pp.89-95
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• 2023

Social phobia is a mental disorder that triggers physical reactions, such as cold sweats, headaches, and panic attacks, as a result of anxiety about a particular situation. Individuals with social phobia are thought to be more sensitive to dental anxiety and may have difficulty visiting the dentist as a result. This study aimed to determine the relationship between social phobia and dental fear among college students, who are reported to have a high prevalence of social phobia. A total of 120 survey responses were analyzed. To investigate the variation in dental fear levels based on the level of social phobia, the total social phobia score was divided into two groups: 41 points or more, and 40 points or less. The disparity in dental fear scores was then analyzed using a t-test. The study found that the average score for dental fear was statistically significantly higher in the group with a total social phobia score of 41 points or more compared to the group with a total score of 40 points or less (p<0.05). Furthermore, the group that scored 41 points or higher on the social phobia scale reported experiencing symptoms such as feeling nauseous at the dentist (3.29 points), sweating upon entering the dentist (3.13 points), and feeling afraid when looking at the dentist (3.13 points). The score was high (p<0.05). Therefore, dental patients exhibiting anxiety symptoms require a comfortable treatment environment to alleviate dental fear, and safe, pain-free dental treatment techniques must be employed.