Upregulation of NAD(P)H:quinone oxidoreductase by radiation potentiates the effect of bioreductive beta-lapachone on cancer cells.

Choi, Eun K,Terai, Kaoru,Ji, In-Mi,Kook, Yeon H,Park, Kyung H,Oh, Eun T,Griffin, Robert J,Lim, Byung U,Kim, Jin-Seok,Lee, Doo S,Boothman, David A,Loren, Melissa,Song, Chang W,Park, Heon Joo Stockton Press 2007 Neoplasia Vol.9 No.8

<P>We found that beta-lapachone (beta-lap), a novel bioreductive drug, caused rapid apoptosis and clonogenic cell death in A549 human lung epithelial cancer cells in vitro in a dose-dependent manner. The clonogenic cell death caused by beta-lap could be significantly inhibited by dicoumarol, an inhibitor of NAD(P)H:quinone oxido-reductase (NQO1), and also by siRNA for NQO1, demonstrating that NQO1-induced bioreduction of beta-lap is an essential step in beta-lap-induced cell death. Irradiation of A549 cells with 4 Gy caused a long-lasting upregulation of NQO1, thereby increasing NQO1-mediated beta-lap-induced cell deaths. Although the direct cause of beta-lap-induced apoptosis is not yet clear, beta-lap treatment reduced the expression of p53 and NF-kappaB, whereas it increased cytochrome C release, caspase-3 activity, and gammaH2AX foci formation. Importantly, beta-lap treatment immediately after irradiation enhanced radiation-induced cell death, indicating that beta-lap sensitizes cancer cells to radiation, in addition to directly killing some of the cells. The growth of A549 tumors induced in immunocompromised mice could be markedly suppressed by local radiation therapy when followed by beta-lap treatment. This is the first study to demonstrate that combined radiotherapy and beta-lap treatment can have a significant effect on human tumor xenografts.</P>

High-resolution tunnelling spectroscopy of a graphene quartet

Song, Young Jae,Otte, Alexander F.,Kuk, Young,Hu, Yike,Torrance, David B.,First, Phillip N.,de Heer, Walt A.,Min, Hongki,Adam, Shaffique,Stiles, Mark D.,MacDonald, Allan H.,Stroscio, Joseph A. Nature Publishing Group, a division of Macmillan P 2010 Nature Vol.467 No.7312

Electrons in a single sheet of graphene behave quite differently from those in traditional two-dimensional electron systems. Like massless relativistic particles, they have linear dispersion and chiral eigenstates. Furthermore, two sets of electrons centred at different points in reciprocal space (??valleys??) have this dispersion, giving rise to valley degeneracy. The symmetry between valleys, together with spin symmetry, leads to a fourfold quartet degeneracy of the Landau levels, observed as peaks in the density of states produced by an applied magnetic field. Recent electron transport measurements have observed the lifting of the fourfold degeneracy in very large applied magnetic fields, separating the quartet into integer and, more recently, fractional levels. The exact nature of the broken-symmetry states that form within the Landau levels and lift these degeneracies is unclear at present and is a topic of intense theoretical debate. Here we study the detailed features of the four quantum states that make up a degenerate graphene Landau level. We use high-resolution scanning tunnelling spectroscopy at temperatures as low as 10??mK in an applied magnetic field to study the top layer of multilayer epitaxial graphene. When the Fermi level lies inside the fourfold Landau manifold, significant electron correlation effects result in an enhanced valley splitting for even filling factors, and an enhanced electron spin splitting for odd filling factors. Most unexpectedly, we observe states with Landau level filling factors of 7/2, 9/2 and 11/2, suggestive of new many-body states in graphene.

Renal Cell Therapy and Beyond

Song, Joon Ho,Humes, H. David Blackwell Publishing Ltd 2009 Seminars in dialysis Vol.22 No.6

<P>Abstract</P><P>Although current dialysis techniques have transformed acute and chronic renal failure from uniformly fatal clinical disorders into treatable diseases, these therapies replace only the water and solute clearance function of the kidney and have reached a point where little further therapeutic improvement can be anticipated. In addition to their metabolic and endocrine functions, renal tubule cells presumably play an important role in the systemic inflammatory balance by participating in the complex and dynamic network of leukocyte action and pro- and anti-inflammatory cytokines. Loss of this function may result in a propensity to develop systemic inflammatory response syndrome (SIRS), multiorgan dysfunction, and a high risk of death in acute kidney injury (AKI), and may relate to chronic inflammatory state in end-stage renal disease (ESRD). A renal tubule cell assist device (RAD) containing animal or human renal tubule cells has been recently developed with the purpose of integrating the functions of tubule cells with the filtration function of current dialysis to offer a more complete renal replacement therapy. The viability and functionality of this device were confirmed in in vitro experiments and large animal studies, and recently the RAD’s clinical therapeutic benefit was demonstrated with a series of FDA-approved human trials. Another novel synthetic membrane extracorporeal device that binds and inhibits circulating leukocytes has been developed with the purpose of reducing microvascular damage promoted primarily via activated circulating leukocytes in AKI and SIRS. This device, called a selective cytopheretic inhibitory device, mimics immunomodulation and duplicates RAD efficiency in preliminary studies. Both devices may become comprehensive treatments, replacing full renal function and correcting inflammatory imbalance in patients with acute and chronic renal disorders.</P>

Building blocks of amorphousGe2Sb2Te5

Lang, Christian,Song, Se Ahn,Manh, Duc Nguyen,Cockayne, David J. H. American Physical Society 2007 Physical review. B, Condensed matter and materials Vol.76 No.5

Design and Modeling of Multistage Depressed Collectors by Using 3D Conformal Finite-difference Time-domain Particle-in-cell Simulations

Ming-Chieh Lin,Peter H. Stoltz,David N. Smithe,Hoyoung Song,김형종,최진주,김선주,Sung Hoon Jang 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.5

The feasibility of designing and modeling a multistage depressed collector (MDC) by using 3D conformal finite-difference time-domain (CFDTD) particle-in-cell (PIC) simulations as implemented in 3D PIC code, VORPAL has been studied. A simple circuit model employing feedback mechanisms has been implemented to provide stable time-dependent voltages for each stage of the depressed collector, and an arbitrary space-time dependent spent-beam distribution is given in our timedomain simulations. We demonstrate the design of a five-stage depressed collector recovering a triangular-like spent-beam distribution imported from a large signal simulation, achieving an energy recovery efficiency of 75%. The MDC after optimization can be integrated into the limited space of an S-band traveling wave tube for a compact microwave power module (MPM).

An Algorithmic Approach to Total Breast Reconstruction with Free Tissue Transfer

유성철,Grant M. Kleiber,David H. Song 대한성형외과학회 2013 Archives of Plastic Surgery Vol.40 No.3

As microvascular techniques continue to improve, perforator flap free tissue transfer is now the gold standard for autologous breast reconstruction. Various options are available for breast reconstruction with autologous tissue. These include the free transverse rectus abdominis myocutaneous (TRAM) flap, deep inferior epigastric perforator flap, superficial inferior epigastric artery flap, superior gluteal artery perforator flap, and transverse/vertical upper gracilis flap. In addition, pedicled flaps can be very successful in the right hands and the right patient, such as the pedicled TRAM flap, latissimus dorsi flap, and thoracodorsal artery perforator. Each flap comes with its own advantages and disadvantages related to tissue properties and donor-site morbidity. Currently, the problem is how to determine the most appropriate flap for a particular patient among those potential candidates. Based on a thorough review of the literature and accumulated experiences in the author’s institution, this article provides a logical approach to autologous breast reconstruction. The algorithms presented here can be helpful to customize breast reconstruction to individual patient needs.

Characterizations of Bone-Like Apatite Powder Fabricated Using Modified Simulated Body Fluid.

An, Ji-Hae,Han, Ok-Seong,Kohn, David H,Park, Yeong-Joon,Song, Ho-Jun American Scientific Publishers 2015 Journal of Nanoscience and Nanotechnology Vol.15 No.8

<P>The objective of this study is to fabricate bone-like apatite (BLAp) powder using the modified simulated body fluid (SBF). The SBF2X and SBF4X groups were prepared by increasing the concentration of inorganic ions by two and four times, respectively, to that of the standard SBF. The mSBF4X group was prepared by particularly increasing the concentrations of calcium and phosphate ions in SBF. Bovine serum albumin (BSA) was added for SBF2X-BSA, SBF4X-BSA, and mSBF4X-BSA groups. BLAp powders were precipitated in these SBFs while being kept at 60 °C. Micro-morphology of BLAp powders showed tens of micrometers-sized rounded clusters which composed with sheet-like nano crystallites. The radius of BLAp clusters were decreased by increasing the concentration of inorganic ions and by incorporating the BSA. The hydroxyapatite crystalline structure was dominant for all sample groups. Further, octacalcium phosphate structure was detected in the mSBF4X group. However, these peaks were decreased in mSBF4X-BSA. FT-IR spectra demonstrated that BSA was co-precipitated in BLAp crystallites, and the amount of BSA was higher in the mSBF4X-BSA group than in the SBF4X-BSA group.</P>

Fabrication and Electrical Characteristics of Graphene-based Charge-trap Memory Devices

이세준,Sung Min Kim,Emil B. Song,Kang L. Wang,David H. Seo,서순애 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.61 No.1

Graphene-based non-volatile charge-trap memory devices were fabricated and characterized to investigate the implementation effect of both 2-dimensional graphene and the 3-dimensional memory structure. The single-layer-graphene (SLG) channel devices exhibit larger memory windows compared to the multi-layer-graphene (MLG) channel devices. This originates from the gate-coupling strength being larger in SLG devices than in MLG devices. Namely, the electrostatic charge screening effect becomes enhanced upon increasing the number of graphene layers; therefore, the gate tunability is reduced in MLG compared to SLG. The results suggest that SLG is more desirable for memory applications than MLG.

An Algorithmic Approach to Total Breast Reconstruction with Free Tissue Transfer

Yu, Seong Cheol,Kleiber, Grant M.,Song, David H. Korean Society of Plastic and Reconstructive Surge 2013 Archives of Plastic Surgery Vol.40 No.3

As microvascular techniques continue to improve, perforator flap free tissue transfer is now the gold standard for autologous breast reconstruction. Various options are available for breast reconstruction with autologous tissue. These include the free transverse rectus abdominis myocutaneous (TRAM) flap, deep inferior epigastric perforator flap, superficial inferior epigastric artery flap, superior gluteal artery perforator flap, and transverse/vertical upper gracilis flap. In addition, pedicled flaps can be very successful in the right hands and the right patient, such as the pedicled TRAM flap, latissimus dorsi flap, and thoracodorsal artery perforator. Each flap comes with its own advantages and disadvantages related to tissue properties and donor-site morbidity. Currently, the problem is how to determine the most appropriate flap for a particular patient among those potential candidates. Based on a thorough review of the literature and accumulated experiences in the author's institution, this article provides a logical approach to autologous breast reconstruction. The algorithms presented here can be helpful to customize breast reconstruction to individual patient needs.

The effects of 10 weeks of β-alanine supplementation on peak power, power drop, and lactate response in Korean national team boxers

Kwang-Jun Kim,Hong-Sun Song,Dong Hyun Yoon,David H. Fukuda,Soon Hee Kim,Dong-Ho Park 한국운동재활학회 2018 JER Vol.14 No.6