CANDELS Sheds Light on the Environmental Quenching of Low-mass Galaxies

Guo, Yicheng,Bell, Eric F.,Lu, Yu,Koo, David C.,Faber, S. M.,Koekemoer, Anton M.,Kurczynski, Peter,Lee, Seong-Kook,Papovich, Casey,Chen, Zhu,Dekel, Avishai,Ferguson, Henry C.,Fontana, Adriano,Giavalis American Astronomical Society 2017 ASTROPHYSICAL JOURNAL LETTERS - Vol.841 No.2

<P>We investigate the environmental quenching of galaxies, especially those with stellar masses (M-*) < 10(9.5) Me-circle dot, beyond the local universe. Essentially all local low-mass quenched galaxies (QGs) are believed to live close to massive central galaxies, which is a demonstration of environmental quenching. We use CANDELS data to test whether or not such a dwarf QG-massive central galaxy connection exists beyond the local universe. For this purpose, we only need a statistically representative, rather than complete, sample of low-mass galaxies, which enables our study to z greater than or similar to 1.5. For each low-mass galaxy, we measure the projected distance (d(proj)) to its nearest massive neighbor (M-* > 10(10.5) M-circle dot) within a redshift range. At a given z and M-*, the environmental quenching effect is considered to be observed if the d(proj) distribution of QGs (d(proj)(Q)) is significantly skewed toward lower values than that of star-forming galaxies (d(proj)(SF)). For galaxies with 10(8) M-circle dot < M-* < 10(10) M-circle dot, such a difference between d(proj)(Q) and d(proj)(SF) is detected up to z similar to 1. Also, about 10% of the quenched galaxies in our sample are located between two and four virial radii (R-Vir) of the massive halos. The median projected distance from low-mass QGs to their massive neighbors, d(proj)(Q)/R-Vir, decreases with satellite M-* at M-* less than or similar to 10(9.5) M-circle dot, but increases with satellite M-* at M-* greater than or similar to 10(9.5) M-circle dot. This trend suggests a smooth, if any, transition of the quenching timescale around M-* similar to 10(9.5) M-circle dot at 0.5 < z < 1.0.</P>

Planck Cold Clumps in the <i>λ</i> Orionis Complex. II. Environmental Effects on Core Formation

Yi, Hee-Weon,Lee, Jeong-Eun,Liu, Tie,Kim, Kee-Tae,Choi, Minho,Eden, David,II, Neal J. Evans,Francesco, James Di,Fuller, Gary,Hirano, N.,Juvela, Mika,Kang, Sung-ju,Kim, Gwanjeong,M. Koch, Patrick,Lee, American Astronomical Society 2018 The Astrophysical journal, Supplement series Vol.236 No.2

<P>Based on the 850 mu m dust continuum data from SCUBA-2 at James Clerk Maxwell Telescope (JCMT), we compare overall properties of Planck Galactic Cold Clumps (PGCCs) in the lambda Orionis cloud to those of PGCCs in the Orion A and B clouds. The Orion A and B clouds are well-known active star-forming regions, while the A Orionis cloud has a different environment as a consequence of the interaction with a prominent OB association and a giant H-II region. PGCCs in the lambda Orionis cloud have higher dust temperatures (T-d = 16.13 +/- 0.15 K) and lower values of dust emissivity spectral index (beta = 1.65 +/- 0.02) than PGCCs in the Orion A (T-d = 13.79 +/- 0.21 K, beta = 2.07 +/- 0.03) and Orion B (T-d = 13.82 +/- 0.19 K, beta =1.96 +/- 0.02) clouds. We find 119 substructures within the 40 detected PGCCs and identify them as cores. Out of a total of 119 cores, 15 cores are discovered in the lambda Orionis cloud, while 74 and 30 cores are found in the Orion A and B clouds, respectively. The cores in the lambda Orionis cloud show much lower mean values of size R = 0.08 pc, column density N(H-2) (9.5 +/- 1.2) x 10(22)cm(-2) , number density n(H-2) - (2.9 +/- 0.4) x 10 5 CM -3 , and mass M-core = 1.0 +/- 0.3 M(circle dot)compared to the cores in the Orion A [R = 0.11 pc, N(H-2) = (2.3 +/- 0.3) x 10(23) cm(-2), n(H-2) = (3.8 +/- 0.5) x 10(5)cm(-3) , and M-core = 2.4 +/- 0.3 M-circle dot] and Orion B [R = 0.16 pc, N(H-2) (3.8 +/- 0.4) x 10(23) cm(-2), n(H-2) = (15.6 +/- 1.8) x 10(5) cm(-3) , and M-core = 2.7 +/- 0.3 M-circle dot] clouds. These core properties in the A Orionis cloud can be attributed to the photodissociation and external heating by the nearby H rr region, which may prevent the PGCCs from forming gravitationally bound structures and eventually disperse them. These results support the idea of negative stellar feedback on core formation.</P>

Self-healing graphene oxide-based composite for electromagnetic interference shielding

Sim, Hyeon Jun,Lee, Duck Weon,Kim, Hyunsoo,Jang, Yongwoo,Spinks, Geoffrey M.,Gambhir, Sanjeev,Officer, David L.,Wallace, Gordon G.,Kim, Seon Jeong Elsevier 2019 Carbon Vol.155 No.-

<P><B>Abstract</B></P> <P>The electromagnetic pollution issues have been arising from the fast-growing development for electronic devices. Hence, the demand for materials with high electromagnetic interference (EMI) shielding performance has increased. Here, we developed self-healable, flexible and printable graphene oxide/silver nanowire films and textiles with excellent EMI shielding performance. The maximum electromagnetic interference shielding effectiveness (EMI SE) of 92 dB was recorded for an 18 μm-thickness film. In addition, the specific EMI shielding effectiveness was 31 dB cm3/g or 48,275 dB cm2/g when normalized to film thickness. Both values are higher than reported EMI shielding products. The composite film and coated textile were tolerant of damage induced by cracking or scratching. Damaging the films by cracking reduced the electrical conductivity, mechanical properties, and the EMI SE was decreased from 72 dB to 56 dB at 8.2 GHz. After the healing process, the EMI SE was recovered to 71 dB and mechanical properties restored. The EMI SE of textile reached a maximum of 30 dB which is suitable to use as a commercial EMI shielding product. In addition, the textile exhibited high flexibility, and showed excellent mechanical stability with no change in performance after 1000 bending cycles.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Multidimensional Helical Nanostructures in Multiscale Nanochannels

Lee, Sunhee,Kim, Hanim,Tsai, Ethan,Richardson, Jacqueline M.,Korblova, Eva,Walba, David M.,Clark, Noel A.,Lee, Sang Bok,Yoon, Dong Ki American Chemical Society 2015 Langmuir Vol.31 No.29

<P>We have investigated the various morphological changes of helical nanofilament (HNF; B4) phases in multiscale nanochannels made of porous anodic aluminum oxide (AAO) film. Single or multihelical structures could be manipulated depending on the AAO pore size and the higher-temperature phase of each molecule. Furthermore, the nanostructures of HNFs affected by the chemical affinity between the molecule and surface were drastically controlled in surface-modified nanochannels. These well-controlled hierarchical helical structures that have multidimensions can be a promising tool for the manipulation of chiral pores or the nonlinear optical applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2015/langd5.2015.31.issue-29/acs.langmuir.5b01620/production/images/medium/la-2015-01620z_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/la5b01620'>ACS Electronic Supporting Info</A></P>

단식 , 재합식(再合食) 및 인슈린 투여 후에 쥐의 간으로부터 분리된 세포핵의 핵단백질 인산화

이효사,데이비드엠깁슨 한국농화학회 1980 Applied Biological Chemistry (Appl Biol Chem) Vol.23 No.1

Labelling of chromatin proteins with 2P was observed after incubating isolated liver nuclei with [γ-32P] ATP for 5 minutes at 37℃. The pattern of labelling with 32P was examined on SDS polyacrylamide gel electrophoresis with nuclei from rats maintained in a starvation state for 48 hours, following refeeding for 12 hours; and from fed streptozotocin-diabetic rats with insulin injection 6 hours before sacrifice. With 48h starved rat liver nuclei the level of phosphorylation for 0.14M NaCl soluble proteins was decreased in the molecular weights between 41,000 and 200,000 dalrons relative to normal controls. Refeeding the starved rats reversed the change of phosphorylation pattern over 12 hour. The level of phosphorylation for five phenol soluble nonhistone proteins with molecular weights above 59,000 daltons was somewhat decreased with 48h starved rat liver nuclei as compared with that of normal controls. Starvation also decreased the phosphorylation level of major histones in relation to normal controls. The experiment with insulin injection into fed streptozotocin-diabetic rats show ed the tendency to increase phosphorylation of 0.14M NaCl soluble proteins (130,000 dalton protein) and phenol soluble non-histone proteins (155,000 dalton protein), The phosphorylation level of histones appeared to be invariant under the experimental conditions employed here. These results suggest the possibility that the phosphorylation and dephosphorylation of 0.14M NaCl soluble proteins and H₁ histone precede those of other chromatin associated nuclear proteins, It is of interest to find that insulin signal was correlated to phosphorylation of nuclear proteins while glucagon signal dephosphorylated nuclear proteins.

Characterization of Highly Pathogenic H5N1 Avian Influenza A Viruses Isolated from South Korea

Lee, Chang-Won,Suarez, David L.,Tumpey, Terrence M.,Sung, Haan-Woo,Kwon, Yong-Kuk,Lee, Youn-Jeong,Choi, Jun-Gu,Joh, Seong-Joon,Kim, Min-Chul,Lee, Eun-Kyoung,Park, Jong-Myung,Lu, Xiuhua,Katz, Jacquelin American Society for Microbiology 2005 Journal of virology Vol.79 No.6

<B>ABSTRACT</B><P>An unprecedented outbreak of H5N1 highly pathogenic avian influenza (HPAI) has been reported for poultry in eight different Asian countries, including South Korea, since December 2003. A phylogenetic analysis of the eight viral genes showed that the H5N1 poultry isolates from South Korea were of avian origin and contained the hemagglutinin and neuraminidase genes of the A/goose/Guangdong/1/96 (Gs/Gd) lineage. The current H5N1 strains in Asia, including the Korean isolates, share a gene constellation similar to that of the Penfold Park, Hong Kong, isolates from late 2002 and contain some molecular markers that seem to have been fixed in the Gs/Gd lineage virus since 2001. However, despite genetic similarities among recent H5N1 isolates, the topology of the phylogenetic tree clearly differentiates the Korean isolates from the Vietnamese and Thai isolates which have been reported to infect humans. A representative Korean isolate was inoculated into mice, with no mortality and no virus being isolated from the brain, although high titers of virus were observed in the lungs. The same isolate, however, caused systemic infections in chickens and quail and killed all of the birds within 2 and 4 days of intranasal inoculation, respectively. This isolate also replicated in multiple organs and tissues of ducks and caused some mortality. However, lower virus titers were observed in all corresponding tissues of ducks than in chicken and quail tissues, and the histological lesions were restricted to the respiratory tract. This study characterizes the molecular and biological properties of the H5N1 HPAI viruses from South Korea and emphasizes the need for comparative analyses of the H5N1 isolates from different countries to help elucidate the risk of a human pandemic from the strains of H5N1 HPAI currently circulating in Asia.</P>

단식 , 재급식(再給食)과 인슈린 주사에 따른 쥐의 간세포핵단백질(肝細胞核蛋白質)에 대한 전기영동상의 분포양상 비교

이효사,데이비드엠깁슨 한국농화학회 1979 Applied Biological Chemistry (Appl Biol Chem) Vol.22 No.3

SDS gel electrophoresis has been employed to examine the changes in distribution of three major classes of nuclear proteins extracted from isolated liver nuclei in response to refeeding of starved rats with a fat-free high carbohydrate diet and following insulin injection into streptozotocin-diabetic rats. The relative quantity of electrophoretically separated proteins in the fraction showed marked changes with 0.14M NaCl extracts, but not with histones and phenol soluble non-histone proteins. During 48h starvation at least five proteins ranging in molecular weight from 50,000 to 180,000 daltons decreased relative to normal controls while a protein with 36,000 daltons was increased. Refeeding the starved rats with a high carbohydrate diet reversed these changes over 24 h. Insulin injection into streptozotocin-diabetic rats increased levels of the set of five 0.14 M NaCl soluble proteins identified from refeeding experiment of starved rats. The 36,000 daltons protein was also diminished. These results indicate that changes in distribution of certain nuclear proteins in 0.14 M NaCl extracts are associated with the control of nuclear activity related to known insulin-signalled modulation and induction of cytosolic lipogenic enzymes.

Nrf2 Expression and Apoptosis in Quercetin-treated Malignant Mesothelioma Cells

Lee, Yoon-Jin,Lee, David M.,Lee, Sang-Han Korean Society for Molecular and Cellular Biology 2015 Molecules and cells Vol.38 No.5

NF-E2-related factor 2 (Nrf2), a basic leucine zipper transcription factor, has recently received a great deal of attention as an important molecule that enhances antioxidative defenses and induces resistance to chemotherapy or radiotherapy. In this study, we investigated the apoptosis-inducing and Nrf2- upregulating effects of quercetin on malignant mesothelioma (MM) MSTO-211H and H2452 cells. Quercetin treatment inhibited cell growth and led to upregulation of Nrf2 at both the mRNA and protein levels without altering the ubiquitination and extending the half-life of the Nrf2 protein. Following treatment with quercetin, analyses of the nuclear level of Nrf2, Nrf2 antioxidant response element-binding assay, Nrf2 promoter-luc assay, and RT-PCR toward the Nrf2-regulated gene, heme oxygenase-1, demonstrated that the induced Nrf2 is transcriptionally active. Knockdown of Nrf2 expression with siRNA enhanced cytotoxicity due to the induction of apoptosis, as evidenced by an increase in the level of proapoptotic Bax, a decrease in the level of antiapoptotic Bcl-2 with enhanced cleavage of caspase-3 and PARP proteins, the appearance of a sub-$G_0/G_1$ peak in the flow cytometric assay, and increased percentage of apoptotic propensities in the annexin V binding assay. Effective reversal of apoptosis was observed following pretreatment with the pan-caspase inhibitor Z-VAD. Moreover, Nrf2 knockdown exhibited increased sensitivity to the anticancer drug, cisplatin, presumably by potentiating the oxidative stress induced by cisplatin. Collectively, our data demonstrate the importance of Nrf2 in cytoprotection, survival, and drug resistance with implications for the potential significance of targeting Nrf2 as a promising strategy for overcoming resistance to chemotherapeutics in MM.

High-quality SNP calling from olive flounder, Paralichthys olivaceus, in Jeju Island, South Korea

Sukkyoung Lee,Taehyug Jeong,W.K.M. Omeka,D.S. Liyanage,Chaehyeon Lim,Kishanthini Nadarajapillai,H.M.V. Udayantha,W.M. Gayashani Sandamalika,Seong-Rip Oh,David B. Jones,Dean R. Jerry,Jehee Lee 한국수산과학회 양식분과 2021 한국수산과학회 양식분과 학술대회 Vol.2021 No.4

Intermediate-term outcomes after robotic ureteral reconstruction for long-segment (≥4 centimeters) strictures in the proximal ureter: A multi-institutional experience

Matthew Lee,Ziho Lee,Helaine Koster,Minsuk Jun,Aeen M. Asghar,Randall Lee,David Strauss,Neel Patel,Daniel Kim,Sreeya Komaravolu,Alice Drain,Michael J. Metro,Lee Zhao,Michael Stifelman,Daniel D. Eun 대한비뇨의학회 2021 Investigative and Clinical Urology Vol.62 No.1

Purpose: To report our intermediate-term, multi-institutional experience after robotic ureteral reconstruction for the management of long-segment proximal ureteral strictures. Materials and Methods: We retrospectively reviewed our Collaborative of Reconstructive Robotic Ureteral Surgery (CORRUS) database to identify all patients who underwent robotic ureteral reconstruction for long-segment (≥4 centimeters) proximal ureteral strictures between August 2012 and June 2019. The primary surgeon determined the specific technique to reconstruct the ureter at time of surgery based on the patient's clinical history and intraoperative findings. Our primary outcome was surgical success, which we defined as the absence of ureteral obstruction on radiographic imaging and absence of obstructive flank pain. Results: Of 20 total patients, 4 (20.0%) underwent robotic ureteroureterostomy (RUU) with downward nephropexy (DN), 2 (10.0%) underwent robotic ureterocalycostomy (RUC) with DN, and 14 (70.0%) underwent robotic ureteroplasty with buccal mucosa graft (RU-BMG). Median stricture length was 4 centimeters (interquartile range [IQR], 4–4; maximum, 5), 6 centimeters (IQR, 5–7; maximum, 8), and 5 centimeters (IQR, 4–5; maximum, 8) for patients undergoing RUU with DN, RUC with DN, and RU-BMG, respectively. At a median follow-up of 24 (IQR, 14–51) months, 17/20 (85.0%) cases were surgically successful. Two of four patients (50.0%) who underwent RUU with DN developed stricture recurrences within 3 months. Conclusions: Long-segment proximal ureteral strictures may be safely and effectively managed with RUC with DN and RU-BMG. Although RUU with DN can be utilized, this technique may be associated with a higher failure rate.