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Millimeter-Scale Growth of Single-Oriented Graphene on a Palladium Silicide Amorphous Film
Kim, Hyun-Woo,Song, Inkyung,Kim, Tae-Hoon,Ahn, Sung Joon,Shin, Ha-Chul,An, Byeong-Seon,Jang, Yamujin,Jeon, Sunam,Kim, Eun Hye,Khadka, Ishwor Bahadur,Gu, TaeJun,Woo, Sun-Hee,Whang, Dongmok,Kim, Youngku American Chemical Society 2019 ACS NANO Vol.13 No.2
<P>It is widely accepted in condensed matter physics and material science communities that a single-oriented overlayer cannot be grown on an amorphous substrate because the disordered substrate randomizes the orientation of the seeds, leading to polycrystalline grains. In the case of two-dimensional materials such as graphene, the large-scale growth of single-oriented materials on an amorphous substrate has remained unsolved. Here, we demonstrate experimentally that the presence of uniformly oriented graphene seeds facilitates the growth of millimeter-scale single-oriented graphene with 3 × 4 mm<SUP>2</SUP> on palladium silicide, which is an amorphous thin film, where the uniformly oriented graphene seeds were epitaxially grown. The amorphous palladium silicide film promotes the growth of the single-oriented growth of graphene by causing carbon atoms to be diffusive and mobile within and on the substrate. In contrast to these results, without the uniformly oriented seeds, the amorphous substrate leads to the growth of polycrystalline graphene grains. This millimeter-scale single-oriented growth from uniformly oriented seeds can be applied to other amorphous substrates.</P> [FIG OMISSION]</BR>
Gradient index lens based combined two-photon microscopy and optical coherence tomography
Wang, Taejun,Li, Qingyun,Xiao, Peng,Ahn, Jinhyo,Kim, Young Eun,Park, Youngrong,Kim, Minjun,Song, Miyeoun,Chung, Euiheon,Chung, Wan Kyun,Ahn, G-One,Kim, Sungjee,Kim, Pilhan,Myung, Seung-Jae,Kim, Ki Hea The Optical Society 2014 Optics express Vol.22 No.11
Park Sang Won,Yeo Na Young,Kang Seonguk,Ha Taejun,Kim Tae-Hoon,Lee DooHee,Kim Dowon,Choi Seheon,Kim Minkyu,Lee DongHoon,Kim DoHyeon,Kim Woo Jin,Lee Seung-Joon,Heo Yeon-Jeong,Moon Da Hye,Han Seon-Sook 대한의학회 2024 Journal of Korean medical science Vol.39 No.5
Background: Worldwide, sepsis is the leading cause of death in hospitals. If mortality rates in patients with sepsis can be predicted early, medical resources can be allocated efficiently. We constructed machine learning (ML) models to predict the mortality of patients with sepsis in a hospital emergency department. Methods: This study prospectively collected nationwide data from an ongoing multicenter cohort of patients with sepsis identified in the emergency department. Patients were enrolled from 19 hospitals between September 2019 and December 2020. For acquired data from 3,657 survivors and 1,455 deaths, six ML models (logistic regression, support vector machine, random forest, extreme gradient boosting [XGBoost], light gradient boosting machine, and categorical boosting [CatBoost]) were constructed using fivefold cross-validation to predict mortality. Through these models, 44 clinical variables measured on the day of admission were compared with six sequential organ failure assessment (SOFA) components (PaO2/FIO2 [PF], platelets (PLT), bilirubin, cardiovascular, Glasgow Coma Scale score, and creatinine). The confidence interval (CI) was obtained by performing 10,000 repeated measurements via random sampling of the test dataset. All results were explained and interpreted using Shapley’s additive explanations (SHAP). Results: Of the 5,112 participants, CatBoost exhibited the highest area under the curve (AUC) of 0.800 (95% CI, 0.756–0.840) using clinical variables. Using the SOFA components for the same patient, XGBoost exhibited the highest AUC of 0.678 (95% CI, 0.626–0.730). As interpreted by SHAP, albumin, lactate, blood urea nitrogen, and international normalization ratio were determined to significantly affect the results. Additionally, PF and PLTs in the SOFA component significantly influenced the prediction results. Conclusion: Newly established ML-based models achieved good prediction of mortality in patients with sepsis. Using several clinical variables acquired at the baseline can provide more accurate results for early predictions than using SOFA components. Additionally, the impact of each variable was identified.
병원획득 Klebsiella pneumoniae 균혈증 분석을 통해 본 Ciprofloxacin 내성과 Extended-Spectrum β-Lactamase생성 간의 연관성
김미영,추은주,곽이경,송문희,나성수,송태준,김성혜,전재범,최상호,정진용,김남중,김양수,우준희,류지소 대한감염학회 2004 감염과 화학요법 Vol.36 No.5
목적 : K. pneumoniae는 ciprofloxacin내성 증가가 전세계적으로 문제가 되고있는 extended-spectrum beta-lactamase (ESBL)를 생성하는 대표적인 세균으로 최근 외국에서 ciprofloxacin 내성과 ESBL 생성사이에 관련이 있다는 2-3편의 보고들이 있었다. 본 연구에서는 병원획득 K. pneumoniae 패혈증이 있었던 환자들을 대상으로 ciprofloxacin 내성과 관련된 인자를 알아보고자 하였다. 재료 및 방법 : 2001년 1월 부터 2002년 12월 사이에 2200병상의 3차 의료기관인 한 대학병원에서 입원 후 72시간 이후에 나간 혈액배양에서 K. pneumoniae가 배양된 입원환자를 대상으로 의무기록과 전산기록을 분석하여 환자의 성별, 나이, 병동, 기저질환, 이전의 항생제 사용력, 패혈증 발생당시까지의 재원기간, 이전 입원력, 원인균의ESBL 생성유무 등을 파악하였고 이들 변수가 ciprofloxacin 내성과 관련이 있는지를 분석하였다. 재발성 패혈증의 경우는 첫 번째 경우만을 분석에 포함하였다. 결과 : 연구대상 환자는 총154명이었고 K. pneumoniae의 ciprofloxacin에 대한 내성률은 28.6% (44/154)였다. Ciprofloxacin 내성균주 중 ESBL 생성균주의 비율은 95.5% (42/44)였고 ciprofloxacin 감수성균주에서 ESBL 생성균주의 비율은 24.5% (27/110)였다(P<0.001). ESBL생성외에 단변량 분석에서 유의한 관련을 보인 변수로는 남자, 나이가 많은 경우, 패혈증 당시 중환자실 재원, 기저질환이 고형암, 혈액암, 담도계 질환인 경우, 패혈증 발생이전 1달 이내의 항생제 사용력, 3세대 cephalosporin, metronidazole, fluroquinolone, carbapenem 투여력이 있었다. 다변량 로지스틱 분석을 시행 하였을 때는 나이가 많은 경우(Adjusted odds ratio[A0R]; 1.04, 95%confidence interval[CI]; 1.01-1.06)와 ESBL 생성(AOR; 81.35, 95% CI; 17.76-372.53)이 유의하게 ciprofloxacin 내성과 관련이 있었다. 결론 : 패혈증을 일으킨 병원획득 K. pneumonias에서의 ciprofloxacin 내성은 ESBL 생성과 유의한 관련을 보였고 향후 이에 관련된 원인이나 기전을 분석하기위한 분자역학적·분자생물학적 연구가 필요하겠다. Background : Strains of ciprofloxacin-resistant Klebsiella pneumoniae have emerged worldwide. We investigated the epidemiology of ciprofloxacin resistance and its relationship to ESBL production in nosocomial K. pneumoniae bacteremia. Materials and Methods : Using the computerized database of clinical microbiology, we identified all patients whose blood culture had yielded K. pneumoniae between January 2001 and December 2002 at a 2200-bed university-affiliated tertiary-care hospital. During the study period, total of 392 episodes of K. pneumoniae bacteremia were documented of which 163 episodes were acquired nosocomially. 9 cases of recurrent episodes were excluded. Results : The resistance rates to ciprofloxacin was 28.6% (44/154). ESBL-production was significantly more common in ciprofloxacin-resistant isolates than in ciprofloxacin-susceptible isolates (95.9% [42/44] vs. 24.5% [27/110], P<0.001). In univariate analysis, following factors were significantly associated with resistance to ciprofloxacin: older age, male sex, ICU admission at the time of bacteremia, prior use of antibiotics within 1 month before bacteremia, solid tumor, hematological malignancy, or biliary disease as underlying disease, and ESBL-production. The prior use of 3^(rd)-generation cephalosprins, metronidazole, fluroquinolone, or carbapenem were also risk factors. Independent risk factors for ciprofloxacin resistance were older age (adjusted odds ratio [AOR]; 1.04, 95% confidence interval [CI]; 1.01-1.06) and ESBL production (AOR; 81.35, 95% CI; 17.76-372.53). Conclusion : The close relationship between ciprofloxacin resistance and ESBL production was documented in nosocomial K. pneumoniae bacteremia. Further epidemiological and molecular studies to determine factors and mechanisms involved in the relationship are needed.
Kim, Dokyoung,Moon, Hyunsoo,Baik, Sung Hoon,Singha, Subhankar,Jun, Yong Woong,Wang, Taejun,Kim, Ki Hean,Park, Byung Sun,Jung, Junyang,Mook-Jung, Inhee,Ahn, Kyo Han American Chemical Society 2015 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.137 No.21
<P>Fluorescence imaging of tissues offer an essential means for studying biological systems. Autofluorescence becomes a serious issue in tissue imaging under excitation at UV-vis wavelengths where biological molecules compete with the fluorophore. To address this critical issue, a novel class of fluorophores that can :be excited at, similar to 900 nm under two-photon excitation conditions and emits in the red wavelength region (>= 600 nm) has been disclosed. The new pi-extended dipolar dye system, shows several advantageous features including minimal antofluorescence in tissue imaging and pronounced solvent-sensitive emission behavior, compared with a widely used two-photon absorbing dye, acedan. As an important application of the new dye system, one of the dyes was developed into a fluorescent probe for amyloicl-beta plaques, a key biomarker of Alzheimer's disease. The probe enabled in Vivo imaging of amyloid-beta plaques in a disease-model mouse, with negligible background signal. The new dye system has great potential for the development of other types of two-photon fluorescent probes and tags for imaging of tissues with minimal autofluorescence.</P>