수막구균 수막염의 인식, 감염병에 대한 일반 지식 및 예방접종 현황 : 국내외 대학 재학생 비교 연구

Shin, Kyungsuk Soonchunhyang University Graduate School 2023 국내박사

Background; Meningococcal meningitis is a disease that can cause severe and possibly fatal side effects. To prevent the spread of meningococcal meningitis, which is a highly transmissible disease, 16 states in the USA mandate entering college students to receive meningococcal vaccination. Nevertheless, South Korea does not. This study aims to point out the importance of meningococcal vaccination by comparing the level of general knowledge and recognition of the requirement for vaccination among university students in the USA/Canada and Korea. Methods: The study was conducted using a self-filled questionnaire survey targeting international and Korean students at one of Korea's universities. The survey focused on topics such as knowledge of infectious diseases that can occur at the dormitory residence, infectious agents and routes of meningococcal meningitis infection and infection route, and students' intention to receive meningococcal vaccination. Results: International university students had a higher awareness of the importance of infectious disease prevention than Korean students (P<0.05) and also had higher meningococcal-related knowledge (P<0.05). International universities strongly recommend meningococcal vaccination compared to Korean universities (P<0.05), and the actual vaccination rate was higher than that of domestic university students (P<0.05). Conclusions: This study found that the awareness of meningococcal vaccination among Korean university students was lower than that of international university students, and the vaccination rate was also lower. Because students often do not get vaccinated due to low awareness of the meningococcal disease, health education programs can increase their knowledge about infectious diseases and awareness of vaccines. Thus, increasing the vaccination rate. 연구 배경: 수막구균성 수막염은 호흡기 또는 사람과의 접촉을 통해 전파되며 심각하면 사망에 이를 수도 있다. 미국에서는 수막구균 예방접종을 의무화하고 있지만 국내는 필수가 아니다. 그렇기 때문에 본 연구를 통해 수막구균과 같은 감염병에 대한 일반적 지식과 예방접종의 필요성에 대한 인지도를 미국 캐나다 대학 재학생과 국내 대학 재학생과 비교 평가하여 수막구균 예방접종의 필요성을 강조하고자 하였다. 방법: 국내〮외 대학생을 대상으로 기숙사 생활시 발생할 수 있는 감염 질환(수막구균성 수막염 포함)관련 지식, 백신 접종 의향 등에 대해 자기 기입 방식으로 조사하였다. 결과: 해외 대학 재학생들은 감염병에 대한 인식이 국내 보다 높았다. 특히 예방접종을 적극 권장하고 있으며 실제 접종률 또한 국내 대학 재학생보다 높았다. 고찰: 국내 대학 재학생의 경우 수막구균 예방접종에 대한 인지도와 접종률 모두 낮았다. 질병에 대한 인식이 낮을 경우 백신접종의 필요성에 대한 인식 또한 낮아진다. 그렇기 때문에 신입생들을 대상으로 감염 질환에 대한 교육을 진행하면 감염병과 백신의 필요성에 대한 인지도를 높일 수 있을 것이다.

고령의 류마티스관절염 환자에서 급성관상동맥증후군에 대한 경피적 관상동맥중재술의 예후

Kim, Bo Young Soonchunhyang University Graduate School 2023 국내박사

ABSTRACT Outcomes of percutaneous coronary intvervention for acute coronary syndrome in elderly patients with rheumatoid arthritis Bo Young Kim, M.D. Department of Internal Medicine Graduate School of Medicine, Soonchunhyang University Asan, Korea Supervised by professor Hyun-Sook Kim, M.D., Ph.D. Objective This study aimed to evaluate the clinical outcomes of elderly patients with and without rheumatoid arthritis (RA) who were diagnosed with acute coronary syndrome and underwent percutaneous coronary intervention (PCI). Methods The Korean National Health Insurance Service claims database was used to extract data on 74,623 (14,074 with RA and 60,549 without RA) aged ≥65 years who were diagnosed with acute coronary syndrome and underwent PCI between 2008 and 2019. The primary outcome was survival between elderly patients with and without RA. The secondary outcome was survival in the RA subgroup. Results During a 10-year follow-up, the all-cause mortality rate was lower in patients with RA than that in patients without (53.7% vs. 58.3%, respectively, log-rank: p < 0.001). In the all-cause mortality RA subgroup, patients with elderly-onset RA had poor survival outcomes, whereas patients with young-onset RA have good survival outcomes compared with that in patients without RA (48.1% vs. 73.7% vs. 58.3%, respectively, log-rank: p < 0.001). The major clinical factors associated with mortality were chronic obstructive pulmonary disease, moderate-to-severe chronic kidney disease, and ST-elevation myocardial infarction diagnosis at PCI index date, in addition to the traditional cardiovascular risk factors. Conclusion Elderly patients with RA who were diagnosed with acute coronary syndrome and underwent PCI had an increased mortality risk, particularly those with elderly-onset RA than young-onset RA. Patient characteristics and clinical factors associated with the survival outcomes need to be considered during the treatment of elderly paitents with RA for a better prognosis of cardiovascular diseases.

Comparison of methylation pattern on fatty acid binding protein 1 promoter region between A549 with HepG2 Cell lines

Lee, Jong-UK Soonchunhyang University Graduate School 2015 국내석사

ABSTRACT Comparison of methylation pattern on fatty acid binding protein 1 promoter region between A549 with HepG2 Jong-Uk Lee Department of Interdisciplinary Program in Biomedical Science Major Graduate School of Soonchunhyang University Asan, Korea (Supervised by Professor Chuch Sik Park) Backgraoud Aspirin-exacerbated respiratory disease (AERD) associated with the development of bronchoconstriction, increased secretion of mucus, infiltration of inflammatory cells in the airway wall in asthmatics following the ingestion of aspirin. AERD indicates inflammation upward trend of generation of cytokine dictated by critical mediators such as leukotrienes (LT). Fatty acid binding proteins (FABPs) play an important role of trafficking in a process of metabolism of intracellular arachidonic acid. Thus it is important to regulate FABP1 expression in a process of eicosanoid metabolism. Describe our previous report in which protein expression of FABP1 was higher in nasal polyp of patients with AERD than ATA. Recently DNA methylation is reported to be associated with gene expression. Objective The aim of this study is to investigate whether CpG methylation or demethylation on FABP1 gene promoter region affect its gene expression using A549 and HepG2 cell lines which shows different level of FABP1. Methods A549 and HepG2 epithelial cells were cultured for 4day after RNA, protein, gDNA extracted from each cell lines. gDNA was C-T conversion by bisulfate and we performed bisulfate PCR. And then, sequence analysis form Macrogen and used to alignment tool, transcription factor binding sites search from PROMO. Results FABP1was shown to have expression of mRNA, protein significantly higher in HepG2 compared with A549. We identified and obtained comparison in terms CpG locis of methylated CpG or unmethylated CpG on FABP1 gene promoter region. A549 cell line have 13 methylated, 6 unmethylated CpG sites on FABP1 gene promoter region while HepG2 cell line have 12 methylated sites, 5 unmethylated sites and 2 partial methylated CpG sites And two cell lines have different methylation patterns to FABP1 promoter region. As a result of search from PROMO for transcription binding factor, it was predicted that there will be transcription binding factor in 4 CpG sites as part of sequence such as -1181( ENKTF-1), -634(E2F-1), -373(PR B, PR A), -25 (GR-alpha, E2F-1, COUP-TF). Conclusion Our results suggest that the level of CpG methylation on promoter region of FABP1 gene could be a factor of differential FABP1 expression between hepatocyte and epithelial cells. We will further validate the effects of binding of Transcription Factor with CpG sites on FABP1 promoter region of A549 and HepG2.

The effect of antiviral agent therapy for moderately severe to profound sudden sensorineural hearing loss

Kim, Beomsoo Soonchunhyang University Graduate School 2023 국내석사

Objectives : Moderately severe to profound idiopathic sudden sensorineural hearing loss (SSNHL) is noted for its poor prognosis. This study aimed to evaluate the effect of the combination of antiviral agents on hearing recovery for moderately severe to profound SSNHL patients. Study design : Prospective Randomized controlled trial Methods : This study is a retrospective analysis of medical records. A total of 147 patients treated at Soonchunhyang University Cheonan Hospital between January 2017 and June 2022, were included in the study and classified into group A and group B according to antiviral agent combination. All groups were administered either intravenous glucocorticoid dexamethasone or oral prednisolone and intratympanic steroid injection. Group A received either intravenous acyclovir or oral famciclovir for antiviral agent. Pure-tone audiometry and speech audiometry performed at first week follow-up and 4-weeks follow-up were compared to evaluate the effect of treatment. The treatment outcome was classified according to modified criteria from American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) and recovery rate (%) was calculated to compare the treatment effect. Results : On hearing test performed at the first-week follow-up, Pure-tone average (PTA) improved in both groups from 87.45±21.60dB HL to 57.52±36.18dB HL in group A and 88.83±20.80dB HL to 76.96±29.57dB HL in group B. The word discrimination score (WDS) also improved from 10.34±15.95% to 50.07±43.67% in group A and 9.78%±15.98% to 26.24%±34.30% in group B. Group A displayed higher recovery on both PTA and WDS than group B, and the difference was statistically significant (p<0.001). On hearing test performed at 4-weeks follow-up, the PTA was 40.07±32.14dB HL in group A and 54.57±30.62dB HL in group B, respectively. WDS was 62.90±41.87% in group A and 49.22±40.55% in group B, respectively. At 4-weeks follow-up, Group A displayed higher recovery on both PTA and WDS, but there was no statistically significant difference. The treatment outcome classified by modified AAO-HNS guideline revealed a higher rate of complete recovery (CR) for moderately severe-to-severe hearing loss patients in group A than group B and the difference was statistically significant at 4-weeks follow-up (p=0.023). The rate of hearing improvement and initial degree of hearing loss was quantified into recovery rate (%), and the recovery rate for PTA at first-week follow-up was higher in group A than group B (50.28±23.20% and 18.30±31.33% respectively), and the difference was statistically significant in group A on every frequency. Conclusion : The antiviral agent combination therapy resulted in an accelerated treatment response and a higher complete recovery rate in moderately severe-to-severe SSNHL patients treated with an antiviral agent combination on modified AAO-HNS criteria. Furthermore, when comparing the effectiveness of combination therapy with antiviral agents based on the recovery rate (%), patients treated with combination therapy showed a higher full recovery rate and accelerated treatment response with antiviral agents. Combination therapy with antiviral agents should be considered in patients with moderately severe to profound sudden sensorineural hearing loss, particularly in patients with moderately severe-to-severe hearing loss. 목적 : 중등고도에서 심도 특발성 돌발성난청은 예후가 좋지 않다는 특징이 있다. 이 연구는 중등고도에서 심도 돌발성 난청 환자들의 청력 회복에 항바이러스제 병용 요법의 효과를 평가하기 위해 수행되었다. 연구대상 및 방법 : 2017년 1월부터 2022년 6월까지 순천향대학교 부속 천안병원에서 돌발성 난청으로 진단받은 환자의 의무기록을 후향적으로 분석하였으며, 치료받은 총 147명의 환자가 연구에 포함되었다. 항바이러스제 병용 요법 시행 여부에 따라 group A와 group B 두 군으로 분류하였다. 두 군 모두 전신적인 고용량 스테로이드 투여가 시행되었고 고실내 스테로이드 주입술이 시행되었으며, A군에서는 경정맥으로 아시클로비르 또는 경구강으로 팜시클로비르를 투여받았다. 치료 효과를 판정하기 위하여 치료 1주 후 청력검사와 치료 4주 후 청력검사를 비교하였다. 치료 결과는 평균청력도와 어음명료도의 호전 정도, 미국 이비인후-두경부외과학회(AAO-HNS) 기준을 수정하여 치료 효과를 비교하였고 또한 회복률 (%)를 측정하여 치료 효과를 비교하였다. 결과 : 치료 1주 후 시행된 청력검사에서 A군에서는 평균 순음역치가 87.45±21.60dB HL에서 57.552±36.18dB HL로 호전되었으며, B 군에서는 88.83±20.80dB HL에서 76.96±29.57dB HL로 호전되어 두 군 모두 호전되었다. 어음명료도에서도 A군에서는 10.34±15.95%에서 50.07±43.67%으로 호전되었으며, B군에서는 9.78±15.98%에서 26.24±34.30%로 호전되었다. A군이 평균 순음역치와 어음명료도에서 B군에 비해 더 높은 호전 정도를 보여 주었다 (p-value <0.001). 치료 4주 후 청력검사에서 A군의 평균 순음역치는 40.07±32.14dB HL로 호전되었으며, B군에서는 57.57±30.62dB HL로 호전되어 두 군 모두 호전되었다. 어음명료도에서도 A군에서는 62.90±41.87%로 호전되었으며, B군에서는 54.57±30.62%로 호전되었다. A군이 평균 순음역치와 어음명료도에서 B군에 비해 더 호전 정도가 더 높은 경향을 보였으나 통계적으로 유의미하지 않았다. 수정된 AAO-HNS 기준으로 분류된 치료 4주 후 치료 결과에서, 중등고도에서 고도 난청 환자들을 선별적으로 비교하였으며 A군이 B군보다 완전회복(Complete recovery) 비율이 높았으며, 이 차이는 통계적으로 유의미했다. 회복률(%)로 측정된 치료 1주 후 결과에서 A군에서 B군보다 평균 순음역치와 어음명료도에서 모두 회복률이 높았으며, 각 주파수별 순음역치 회복률도 A군에서 높았다. 결론 : 항바이러스제 병합 요법을 사용한 경우 치료반응을 앞당기었고 수정된 AAO-HNS 기준에 따라 증둥고도에서 심도의 돌발성난청 환자들에서 항바이러스제 병합 요법의 효과를 비교할 경우 항바이러스제 병용 요법으로 치료한 경우 더 높은 완전 회복률을 보였다. 또한, 회복율(%)을 기준으로 항바이러스제 병용 요법의 효과를 비교할 때, 병용 요법으로 치료받은 환자들은 더 높은 완전 회복률과 빠른 치료 반응을 보였다. 중등고도에서 심도 돌발성 난청 환자들에게는 항바이러스제 병용 요법을 고려해야하며, 특히 중등고도에서 고도 난청의 환자들에게 고려해보아햐 한다.

Gross hematuria and kidney consequences after COVID-19 vaccination

Shin, dalsik Soonchunhyang University Graduate School 2023 국내석사

The coronavirus disease-19 (COVID-19) vaccination can result in kidney-related complications such as abnormal urine tests and reduced renal function, which are rare and can only be detected through testing. Macroscopic hematuria, a condition that is easily noticed without the need for special tests, is considered a cause for great concern for most individuals. The current study aimed to examine the frequency of kidney-related complications, with a specific focus on gross hematuria, and to determine its influence on the clinical course of kidney disease. The retrospective questionnaire survey was performed on the patients visiting Soonchunhyang University Cheonan Hospital's nephrology outpatient department between January 1 and September 30, 2022. The questionnaire included vaccine type, dosage, vaccination date, and complications, including gross hematuria and other systemic symptoms. If gross hematuria occurred, its duration was recorded, and the laboratory parameter was followed up. A total of 281 vaccinated patients with biopsy-proven glomerulonephritis, abnormal urinalysis, or chronic kidney disease were enrolled. Ten gross hematuria events were observed. All the cases were related to the mRNA vaccine (9 with mRNA-1273 of Moderna and 1 with BNT162b2 of Pfizer-BioNTech). Two patients experienced gross hematuria after the first dose of vaccination and eight cases after the second dose. The mean onset time was 1.6 ± 0.8 days, and the duration was 5.0 ± 4.8 days. Fever, headache, fatigue, and chilling were frequent accompanied symptoms. Five patients had already been diagnosed with Immunoglobulin A nephropathy by renal biopsy. Two of the Immunoglobulin A nephropathy patients experienced the aggravation of proteinuria after the gross hematuria event. Five patients were newly diagnosed with glomerulonephritis (3 of Immunoglobulin A nephropathy, 1 of minimal change disease) and systemic disease (1 of rhabdomyolysis). The mRNA COVID-19 vaccination could provoke gross hematuria and could be related to the new development or aggravation of glomerulonephritis. Physicians should recognize the potential harm of vaccination and carefully monitor kidney function after the gross hematuria event.

혈액 세포 이미지 증강을 위한 디퓨전 기반 와서스타인 생성적 적대 신경망

Edward, Emmanuel Soonchunhyang University Graduate School 2023 국내석사

백혈구(WBC)는 면역 체계의 중요한 요소로, 그 수와 차이 세기는 혈액 관련 장애를 진단하는 데 중요합니다. 이전 연구는 주로 인간의 눈으로 쉽게 식별할 수 있는 주요 백혈구 클래스를 분류하는 데 초점을 맞추었습니다. 그러나 우리는 불 규칙한 모양을 가진 몇 가지 백혈구 클래스를 수동으로 구별하기 어려운 모델을 분석했습니다. 합성곱 신경망(CNN)은 이러한 작은 분류를 정확하게 분류하는 데 에 있어서 현저한 진전을 보여주었습니다. 그러나 이러한 모델의 정확도는 주로 적절한 데이터셋의 유무에 따라 달라집니다. 희귀한 백혈구 클래스의 경우 적절한 데이터셋을 확보하는 것은 어려운 도전이 될 수 있습니다. 이를 해결하기 위해, 우리는 잡음 제거 확산 확률 모델의 전방 확산 과정을 이용하여 순수하게 잡음이 섞인 WBC 이미지 벡터를 생성하는 확산 기반 Wasserstein 생성적 적대 신경망을 제안했습니다. 우리는 대한민국 순천향대학교 부천병원의 실제 데이터셋인 4,503 개의 19개 WBC 클래스 이미지를 사용하여 우리의 모델을 평가했습니다. 또한 서 포트 벡터 머신(SVM)을 분류기로 사용하고 사전 훈련된 CNN을 특징 추출기로 사용하여 분류 정확도를 향상시키기 위해 머신 러닝 모델을 결합했습니다. 데이터 불균형 문제를 해결하기 위해 제안된 증강 접근 방식을 사용한 ResNet50-SVM은 19개 클래스의 WBC를 분류하는 데에 평균 정확도 95%를 달성했습니다. 생성된 WBC 이미지는 도메인 전문가에 의해 실험적으로 확인된 대로 원본 이미지와 높은 유사성을 보였습니다. White blood cells (WBC) are vital elements of the immune system, and their number and differential count are crucial for diagnosing blood-related disorders. Previous research has primarily focused on classifying major classes of WBCs that are easily identifiable by the human eye. However, we analyzed a model that encompasses up to 19 classes of WBCs, some of which have irregular shapes and are difficult to differentiate manually. Convolutional neural networks (CNN) have shown remarkable progress in accurately classifying these minute classifications. Nevertheless, the accuracy of these models depends mainly on the availability of appropriate datasets, which can be challenging to obtain for rare WBC classes. To address this, we proposed the diffusion-based Wasserstein Generative Adversarial Network that utilizes the forward diffusion process of the denoising diffusion probabilistic model to generate purely noised WBC image vectors that go as input to the generator. We evaluated our model on a real-world dataset of 4,503 images of the 19 WBC classes from Soonchunhyang University Bucheon Hospital, Korea. We also combined machine learning models to improve classification accuracy, using support vector machines (SVM) as classifiers and pre-trained CNN as feature extractors. After using the proposed augmentation approach to address the data imbalance problem, ResNet50-SVM achieved an average accuracy of 95% in classifying 19 classes of WBC. The generated WBC images exhibited high similarity to the original images, as confirmed experimentally by a domain expert.

Patent foramen ovale screening using transthoracic contrast echocardiography in patients with cryptogenic stroke

최재혁 Soonchunhyang University 2019 국내박사

Patent foramen ovale (PFO) is significantly associated with cryptogenic ischemic stroke. Although transesophageal echocardiography (TEE) is the gold standard for diagnosing PFO, it is expensive, invasive, difficult to perform, and often intolerable. Thus, this study aimed to evaluate the usefulness of transthoracic agitated saline echocardiography (ASE) as a screening method for PFO. This study included 303 patients (mean age, 53 ± 9 years; 191 [63%] men) who were admitted with acute stroke. Patients underwent transthoracic ASE and TEE. Eighty-eight out of 92 patients with positive ASE and 157 out of 211 patients with negative ASE findings underwent TEE to confirm PFO. Of 67 patients with confirmed PFO, 62 (92.5%) showed positive ASE. All patients with grade ≥ 2 Right to left shunt (RLS) were confirmed with PFO. The sensitivity and specificity of ASE were 92.5% and 85.4%, respectively. The positive and negative predictive values of ASE were 70.5% and 96.8%, respectively. Transthoracic ASE showed high sensitivity, specificity, and negative predictive value in the diagnosis of PFO. Our findings suggest that transthoracic ASE is valuable for an easier diagnosis of PFO and for identifying shunt grade in stroke patients who have difficulties with TEE. In addition, ASE should be useful for finding remnant RLS after PFO device closure.

Screening for RNA targets and interacting proteins of Spoonbill, a RNA-binding protein localized on the outer membrane of mitochondria

NGUYEN THI THANH MY Soonchunhyang University Graduate school 2020 국내석사

Most proteins are specifically localized in membrane-covered organelles as well as in non-membrane bound compartments. The protein localizations restrict their interacting partners and regulate the assembly of the integrated macromolecular complexes, through which proteins are facilitated to exert the proper function. Conversely, the mislocalization of proteins is known to lead to diverse human diseases, including neurodegenerative disease and cancer. Mitochondria are essential organelles that not only supply cellular energy but also regulate apoptosis and calcium signaling. Mitochondria have their own genome, but most of the mitochondrial proteins are encoded by the nuclear genome, translated into the cytoplasm and imported into the mitochondria. Thus, proper targeting of proteins into mitochondria, which is well known to be mediated through polypeptide position signals, is important for the biosynthesis and function of mitochondria. In addition to conventional protein targeting, the outer mitochondrial membrane-coupled translation based on localized RNA has recently been highlighted as another efficient mechanism for importing mitochondrial proteins. Spoonbill is a RNA-binding protein that localizes at the outer membrane of mitochondria and plays an important role in mtDNA replication and mitochondrial biogenesis. Spoonbill has been shown to recruit Larp to the mitochondrial surface and form a complex that enhances the translation of several nuclear-encoded mitochondrial genes in Drosophila ovaries. However, the mechanism of Spoonbill-mediated selective local translation is largely unknown. Here, to find out how many mitochondrial-related genes are regulated by Spoonbill at the genome-scale and what kinds of Spoonbill interacting proteins are involved, RNA- and protein- interactome of Spoonbill has been addressed using proximity-crosslinking based purification method. This global interactome analysis will help to uncover the molecular basis of mitochondrial localized translation.

의생명 및 조직공학용 나노셀룰로오스 기반의 온도감응 주사형 하이드로젤 및 그 복합체 연구

Nguyen Ho Minh Trang Soonchunhyang University Graduate School 2018 국내석사

TEMPO–oxidized cellulose nanofiber (TOCNF) and cellulose nanocrystals (CNC) are natural material extracted from cellulose with many promising properties, including biocompatibility and degradability. In this thesis, we used both types of nanocellulose (TOCNF and CNC) in fabricating of injectable thermosensitive hydrogel and composite for biomedical and tissue engineering, especially bone healing application. In the first study, we integrated TOCNF at different concentrations (0.2, 0.4, 0.6, 0.8% w/v) with chitosan (CS) and created a thermosensitive injectable hydrogel intended for biomedical applications. These hydrogels can undergo sol-gel transition at body temperature through interactions between chitosan and β-glycerophosphate. The addition of TOCNF resulted in faster gelation time and increased porosity. These hydrogels with TOCNF showed improved biocompatibility both in vitro and in vivo compared to CS hydrogel. Both MC3T3-E1 pre-osteoblast cells and L929 fibroblast cells showed biocompatibility towards CS/ TOCNF 0.4. After 7 days of implantation, initial inflammatory response to CS/TOCNF 0.4 was found. Such response was significantly subsided within 14 days. Cell infiltration within the hydrogel was also prominent, showing anti-inflammatory or wound healing (M2) macrophage at 14 days after implantation. These results showed that the addition of TOCNF could significantly improve the biocompatibility of CS hydrogel as a biomaterial for biomedical application. Based on result of the first study, we developed CS/TOCNF hydrogels as drug delivery system for bone defect healing in the second study. CS/TOCNF was loaded FK506 to support faster bone formation and was added NaHCO3 in gel agent to enhance gelation properties. The result indicated that higher content of NaHCO3 resulted in faster sol/gel transition and slower degradation of CS/TOCNF hydrogel suitably for bone treatment. FK506 low concentration 5nM is suitable to load in CS/TOCNF hydrogel for development and differentiation of pre-osteoblast MC3T3-E1 cells in vitro (2D culture). Also, CS/TOCNF hydrogel showed success in injection to bone defects in vivo. The last study focused on fabrication of novel brushite cement for bone treatment and evaluate effect of cellulose nanocrystals incorporation in brushite cement. Brushite cement can inject easily within setting time and harden overtime. Addition of cellulose nanocrystal in brushite cement resulted in faster rate of final setting time, increasing size of formed brushite crystals, and quicker degradation. Moreover, like TOCNF, CNC also enhances biological activity brushite cement in vitro with reduction of toxic and good cell adhesion support.

Estimation of respiratory rate using a microphone on face masks in various environments : 다양한 환경에서 안면마스크의 마이크를 이용한 호흡수 예측

LimChhayly Soonchunhyang University Graduate School 2021 국내석사

The respiratory rate (RR) is an important sign for predicting various critical clinical events. Numerous studies have proposed different methods to estimate RR. However, those researches conducted experiments in a controlled environment. Therefore, this study aims to measure RR by using nasal and mouth breath sound recordings from a microphone placed inside face masks during experiments in structured and complex environments. In addition, 3- ix - types of mask such as surgical, KF94, and reusable masks were used to conduct experiments in 4 environments including a room, a bus, a street, and a subway. The participants were instructed to inhale at each beeping sound and exhale before the next beep occurred at a metronome rate produced by a smartphone application ranging from 0.2 to 0.4 (Hz) which resembles 12 to 24 (breaths/min). Thus, during the experiment, the participants were required to wear the proposed masks and earphones to listen to the beeping sounds. By our observation, the non-parametric periodogram method seems to have better performance for RR estimation. Therefore, the Welch periodogram method was used to estimate the power spectral density (PSD) of the breathing signal envelope and measure a RR by finding the peak of PSD. We collected data from 10 healthy participants for experiments. The first experiment by only breath through the nose achieved a median and IQR of accuracy and repeatability of 0% for all cases. The second experiment by only breath through the mouth yielded a median and IQR of accuracy and repeatability of 0% for most cases, only IQR of repeatability was increased in the train environment at 0.2 Hz. Finally, the last experiment which breathed 30s through the nose and 30s through the mouth obtained 0% in the median of accuracy and repeatability for every case. However, the IQR of repeatability was increased in a bus and a train. In short, most experiments achieved a median and IQR of accuracy and repeatability as low as 0%. Furthermore, the duration of the signal that was used for RR estimation is only 20 seconds which is a real-time estimation and has been considered by a majority of previous studies.