Wafer-scale single-crystal hexagonal boron nitride film via self-collimated grain formation

Lee, Joo Song,Choi, Soo Ho,Yun, Seok Joon,Kim, Yong In,Boandoh, Stephen,Park, Ji-Hoon,Shin, Bong Gyu,Ko, Hayoung,Lee, Seung Hee,Kim, Young-Min,Lee, Young Hee,Kim, Ki Kang,Kim, Soo Min American Association for the Advancement of Scienc 2018 Science Vol.362 No.6416

<P><B>Wafer-scale hBN crystalline films</B></P><P>Although wafer-scale polycrystalline films of insulating hexagonal boron nitride (hBN) can be grown, the grain boundaries can cause both scattering or pinning of charge carriers in adjacent conducting layers that impair device performance. Lee <I>et al.</I> grew wafer-scale single-crystal films of hBN by feeding the precursors into molten gold films on tungsten substrates. The low solubility of boron and nitrogen in gold caused micrometer-scale grains of hBN to form that coalesced into single crystals. These films in turn supported the growth of epitaxial wafer-scale films of graphene and tungsten disulfide.</P><P><I>Science</I>, this issue p. 817</P><P>Although polycrystalline hexagonal boron nitride (PC-hBN) has been realized, defects and grain boundaries still cause charge scatterings and trap sites, impeding high-performance electronics. Here, we report a method of synthesizing wafer-scale single-crystalline hBN (SC-hBN) monolayer films by chemical vapor deposition. The limited solubility of boron (B) and nitrogen (N) atoms in liquid gold promotes high diffusion of adatoms on the surface of liquid at high temperature to provoke the circular hBN grains. These further evolve into closely packed unimodal grains by means of self-collimation of B and N edges inherited by electrostatic interaction between grains, eventually forming an SC-hBN film on a wafer scale. This SC-hBN film also allows for the synthesis of wafer-scale graphene/hBN heterostructure and single-crystalline tungsten disulfide.</P>

Subspecific Status of the Korean Tiger Inferred by Ancient DNA Analysis

Lee, Mu-Yeong,Hyun, Jee-Yun,Lee, Seo-Jin,An, Jung-Hwa,Lee, Eun-Ok,Min, Mi-Sook,Kimura, Junpei,Kawada, Shin-Ichiro,Kurihara, Nozomi,Luo, Shu-Jin,O'Brien, Stephen J.,Johnson, Warren E.,Lee, Hang The Korean Society of Systematic Zoology 2012 Animal Systematics, Evolution and Diversity Vol.28 No.1

The tiger population that once inhabited the Korean peninsula was initially considered a unique subspecies (Panthera tigris coreensis), distinct from the Amur tiger of the Russian Far East (P. t. altaica). However, in the following decades, the population of P. t. coreensis was classified as P. t. altaica and hence forth the two populations have been considered the same subspecies. From an ecological point of view, the classification of the Korean tiger population as P. t. altaica is a plausible conclusion. Historically, there were no major dispersal barriers between the Korean peninsula and the habitat of Amur tigers in Far Eastern Russia and northeastern China that might prevent gene flow, especially for a large carnivore with long-distance dispersal abilities. However, there has yet to be a genetic study to confirm the subspecific status of the Korean tiger. Bone samples from four tigers originally caught in the Korean peninsula were collected from two museums in Japan and the United States. Eight mitochondrial gene fragments were sequenced and compared to previously published tiger subspecies' mtDNA sequences to assess the phylogenetic relationship of the Korean tiger. Three individuals shared an identical haplotype with the Amur tigers. One specimen grouped with Malayan tigers, perhaps due to misidentification or mislabeling of the sample. Our results support the conclusion that the Korean tiger should be classified as P. t. altaica, which has important implications for the conservation and reintroduction of Korean tigers.

Subspecific Status of the Korean Tiger Inferred by Ancient DNA Analysis

Mu-Yeong Lee,Jee Yun Hyun,Seo-Jin Lee,Junghwa An,Eunok Lee,Mi-Sook Min,Junpei Kimura,Shin-ichiro Kawada,Nozomi Kurihara,Shu-Jin Luo,Stephen J. O’Brien,Warren E. Johnson,Hang Lee 한국동물분류학회 2012 Animal Systematics, Evolution and Diversity Vol.28 No.1

The tiger population that once inhabited the Korean peninsula was initially considered a unique subspecies (Panthera tigris coreensis), distinct from the Amur tiger of the Russian Far East (P. t. altaica). However, in the following decades, the population of P. t. coreensis was classified as P. t. altaica and hence forth the two populations have been considered the same subspecies. From an ecological point of view, the classification of the Korean tiger population as P. t. altaica is a plausible conclusion. Historically, there were no major dispersal barriers between the Korean peninsula and the habitat of Amur tigers in Far Eastern Russia and northeastern China that might prevent gene flow, especially for a large carnivore with long-distance dispersal abilities. However, there has yet to be a genetic study to confirm the subspecific status of the Korean tiger. Bone samples from four tigers originally caught in the Korean peninsula were collected from two museums in Japan and the United States. Eight mitochondrial gene fragments were sequenced and compared to previously published tiger subspecies’ mtDNA sequences to assess the phylogenetic relationship of the Korean tiger. Three individuals shared an identical haplotype with the Amur tigers. One specimen grouped with Malayan tigers, perhaps due to misidentification or mislabeling of the sample. Our results support the conclusion that the Korean tiger should be classified as P. t. altaica, which has important implications for the conservation and reintroduction of Korean tigers.

Orientational and electro-optical properties of liquid crystal aligned with a directly spinnable carbon nanotube web

Lee, Hyojin,Lee, Ji-Hoon,Huynh, Chi P.,Hawkins, Stephen C.,Musameh, Mustafa,Kim, Dae Hyung,Lee, Seung Hee,Choi, Jonghyun Informa UK (TaylorFrancis) 2015 Liquid crystals Vol.42 No.3

Rpd3L HDAC links H3K4me3 to transcriptional repression memory

Lee, Bo Bae,Choi, Ahyoung,Kim, Ji Hyun,Jun, Yukyung,Woo, Hyeonju,Ha, So Dam,Yoon, Chae Young,Hwang, Jin-Taek,Steinmetz, Lars,Buratowski, Stephen,Lee, Sanghyuk,Kim, Hye Young,Kim, TaeSoo Oxford University Press 2018 Nucleic acids research Vol.46 No.16

<P><B>Abstract</B></P><P>Transcriptional memory is critical for the faster reactivation of necessary genes upon environmental changes and requires that the genes were previously in an active state. However, whether transcriptional repression also displays ‘memory’ of the prior transcriptionally inactive state remains unknown. In this study, we show that transcriptional repression of ∼540 genes in yeast occurs much more rapidly if the genes have been previously repressed during carbon source shifts. This novel transcriptional response has been termed transcriptional repression memory (TREM). Interestingly, Rpd3L histone deacetylase (HDAC), targeted to active promoters induces TREM. Mutants for Rpd3L exhibit increased acetylation at active promoters and delay TREM significantly. Surprisingly, the interaction between H3K4me3 and Rpd3L via the Pho23 PHD finger is critical to promote histone deacetylation and TREM by Rpd3L. Therefore, we propose that an active mark, H3K4me3 enriched at active promoters, instructs Rpd3L HDAC to induce histone deacetylation and TREM.</P>

Examining validity evidence for multidimensional forced choice measures with different scoring approaches

Lee, Philseok,Lee, Sunhee,Stark, Stephen Pergamon 2018 Personality and individual differences Vol. No.

<P><B>Abstract</B></P> <P>This study aims to investigate whether the Thurstonian Item Response Theory (TIRT), a recently developed normative scoring method, yields better validity evidence than the traditional partially ipsative scoring methods for multidimensional forced choice measures. For this purpose, we compared the construct- and criterion-related validity evidence of three different scoring methods for MFC measures, including 1) a partially ipsative method based on classical test theory (PI-CTT), 2) an analogous partially ipsative method using the graded item response theory (PI-IRT), and 3) the TIRT method. We also included in our analyses the validity evidence for a single-statement (SS) Big Five personality measures. Overall, the validity evidence for the three types of MFC scoring methods was comparable to the validity evidence for the traditional summative scoring (SS-CTT) method. Interestingly enough, the PI-CTT scoring method, the simplest method for MFC scoring, was about as effective as the more complex TIRT method. We discuss practical implications of the results and offer suggestions for future research.</P> <P><B>Highlights</B></P> <P> <UL> <LI> All three partially ipsative (PI) scoring methods yielded good validity evidence. </LI> <LI> Thurstonian Item Response Theory (TIRT) also provided good validity evidence. </LI> <LI> The simplest PI scoring method was about as effective as the complex TIRT method. </LI> <LI> TIRT methods are more desirable than the PI method for testing applications. </LI> </UL> </P>

Comparative serology of human brucellosis in Korea

Lee, Sung-Il,Choi, Min-Jung,Hur, Jin,Islam, Md Ariful,Khatun, Mst Minara,Baek, Byeong-Kirl,Lee, Chang-Seup,Kakoma, Ibulaimu,Bolye, Stephen M,Srirangananathan, Nammalwar,Young, Edward John The Korean Society of Veterinary Service 2008 韓國家畜衛生學會誌 Vol.31 No.3

The study was carried out to evaluate the diagnostic efficacy of the tube agglutination test (TAT), enzyme-linked immunosorbent assay (ELISA) and the 2-Mercaptoethanol agglutination test (2-MAT) to detect human brucellosis patients in Korea. We examined 87 serum samples of people in the rural farm areas where bovine brucellosis had been reported. People in this study were divided into seven groups- farmers and their families, veterinarians, veterinary quarantine workers, livestock health control officers, artificial inseminators, livestock traders and healthy control individuals. Among 87 people, 65 were males and 22 were females ranging in age from 13 to 72 years. Of 87 serum samples, ELISA detected 21.84%, TAT detected 11.50% and 2-MAT detected 8.05% Brucella positive sera. Brucella specific IgG ELISA antibody titer was recorder higher in the individuals between the ages of 50 and 65 years. The highest prevalence rate of brucellosis(29.4%) was recorded in the cattle farmers and their family members followed by quarantine veterinary office workers (25%) and practicing veterinarians 01.1%). The majority of the Brucella sero-positive individuals in this study had a history of direct contact with animals.

Interobserver Reliability of Four Diagnostic Methods Using Traditional Korean Medicine for Stroke Patients

Lee, Ju Ah,Ko, Mi Mi,Kang, Byoung-Kab,Alraek, Terje,Birch, Stephen,Lee, Myeong Soo Hindawi Publishing Corporation 2014 Evidence-based Complementary and Alternative Medic Vol.2014 No.-

<P><I>Objective</I>. The aim of this study is to evaluate the consistency of pattern identification (PI), a set of diagnostic indicators used by traditional Korean medicine (TKM) clinicians. <I>Methods</I>. A total of 168 stroke patients who were admitted into oriental medical university hospitals from June 2012 through January 2013 were included in the study. Using the PI indicators, each patient was independently diagnosed by two experts from the same department. Interobserver consistency was assessed by simple percentage agreement as well as by kappa and AC<SUB>1</SUB> statistics. <I>Results</I>. Interobserver agreement on the PI indicators (for all patients) was generally high: pulse diagnosis signs (AC<SUB>1</SUB> = 0.66–0.89); inspection signs (AC<SUB>1</SUB> = 0.66–0.95); listening/smelling signs (AC<SUB>1</SUB> = 0.67–0.88); and inquiry signs (AC<SUB>1</SUB> = 0.62–0.94). <I>Conclusion</I>. In four examinations, there was moderate agreement between the clinicians on the PI indicators. To improve clinician consistency (e.g., in the diagnostic criteria used), it is necessary to analyze the reasons for inconsistency and to improve clinician training.</P>

General M-estimation and its bootstrap

Stephen M.S. Lee 한국통계학회 2012 Journal of the Korean Statistical Society Vol.41 No.4

In M-estimation problems involving estimands in Banach spaces, the M-estimators, when appropriately centred and normed, are shown to converge weakly to maximizers of Gaussian processes under rather general conditions. The conventional bootstrap method fails in general to consistently estimate the limit law.Weshow that themout of n bootstrap,on the other hand, is weakly consistent under conditions similar to those required for weak convergence of the M-estimators. Strong consistency is also proved under more stringent conditions. Examples of applications are given to illustrate the generality of our results.

Impairment of microtubule-dependent trafficking by overexpression of alpha-synuclein.

Lee, He-Jin,Khoshaghideh, Farnaz,Lee, Stephen,Lee, Seung-Jae Published on behalf of the European Neuroscience A 2006 The European journal of neuroscience Vol.24 No.11

<P>Abnormal accumulation of alpha-synuclein (alpha-syn) has been linked to several neurological disorders, including Parkinson's disease (PD). However, the underlying mechanism by which alpha-syn accumulation affects neuronal function and survival remains unknown. Here, we provide data suggesting a possible effect of aggregated alpha-syn on the microtubule (MT) network. Consistent with the MT dysfunction, we also observed other degenerative changes, such as neuritic degeneration, trafficking defects, and Golgi fragmentation, which are common pathological features shared by many human neurodegenerative diseases. Neuritic degeneration and Golgi fragmentation were confirmed in primary cultures of dorsal root ganglia (DRG) neurons overexpressing alpha-syn. This effect of alpha-syn seems to have some selectivity to the MT system, as actin microfilaments and MT-independent trafficking remain unaffected. Within the degenerating neurites, we found numerous spherical co-aggregates of alpha-syn and tubulins, from which actin was excluded. These studies suggest that the MT system is a potential target of alpha-syn, and impairment of this system might have impacts on neuronal structure and function.</P>