Raman-amplification and polarization-dependence measurement in a methane Raman shifter seeded by a liquid Raman oscillator

We perform Raman amplification in a high-pressure methane cell seeded by a low-threshold liquid Raman oscillator. The Raman frequency of the oscillator medium, dimethyl sulfoxide (DMSO), is tuned when it is mixed with water to fit the Raman frequency of methane. The Raman gain in this configuration is not so sensitive to the methane pressure, and the conversion efficiency is high. Using this configuration, we measure the polarization dependence of the Raman amplifier. An experiment is performed for three typical polarization states. Complete gain suppression is expected in some polarization states, but there is a little gain because of the incompleteness of the polarization state. Theoretically the results are analyzed when the x and the y components of the scattered waves are coupled.     

Physical and Sexual Intimate Partner Violence Among Women in Methadone Maintenance Treatment.

Although several studies have examined the relationship between intimate partner violence (IPV) and drug use among women in drug treatment programs, more information is needed to delineate differences, as a function of the specific drug used. Data from a random sample of 416 women attending methadone programs were analyzed to elucidate the differential associations between IPV and use of the following: marijuana only, cocaine only, heroin only, or cocaine and heroin. Prevalence of IPV among this sample far exceeded estimates from the general population. After adjusting for sociodemographic variables, use of cocaine only was significantly associated with an increased likelihood of experiencing IPV compared with no drug use. Similar results were found for women using both cocaine and heroin. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

HDAC8-Selective Inhibition by PCI-34051 Enhances the Anticancer Effects of ACY-241 in Ovarian Cancer Cells

HDAC6 is overexpressed in ovarian cancer and is known to be correlated with tumorigenesis. Accordingly, ACY-241, a selective HDAC6 inhibitor, is currently under clinical trial and has been tested in combination with various drugs. HDAC8, another member of the HDAC family, has recently gained attention as a novel target for cancer therapy. Here, we evaluated the synergistic anticancer effects of PCI-34051 and ACY-241 in ovarian cancer. Among various ovarian cancer cells, PCI-34051 effectively suppresses cell proliferation in wild-type p53 ovarian cancer cells compared with mutant p53 ovarian cancer cells. In ovarian cancer cells harboring wild-type p53, PCI-34051 in combination with ACY-241 synergistically represses cell proliferation, enhances apoptosis, and suppresses cell migration. The expression of pro-apoptotic proteins is synergistically upregulated, whereas the expressions of anti-apoptotic proteins and metastasis-associated proteins are significantly downregulated in combination treatment. Furthermore, the level of acetyl-p53 at K381 is synergistically upregulated upon combination treatment. Overall, co-inhibition of HDAC6 and HDAC8 through selective inhibitors synergistically suppresses cancer cell proliferation and metastasis in p53 wild-type ovarian cancer cells. These results suggest a novel approach to treating ovarian cancer patients and the therapeutic potential in developing HDAC6/8 dual inhibitors.     

Mass Spectrometry-Based Disulfide Mapping of Lysyl Oxidase-like 2

Lysyl oxidase-like 2 (LOXL2) catalyzes the oxidative deamination of peptidyl lysines and hydroxylysines to promote extracellular matrix remodeling. Aberrant activity of LOXL2 has been associated with organ fibrosis and tumor metastasis. The lysine tyrosylquinone (LTQ) cofactor is derived from Lys653 and Tyr689 in the amine oxidase domain via post-translational modification. Based on the similarity in hydrodynamic radius and radius of gyration, we recently proposed that the overall structures of the mature LOXL2 (containing LTQ) and the precursor LOXL2 (no LTQ) are very similar. In this study, we conducted a mass spectrometry-based disulfide mapping analysis of recombinant LOXL2 in three forms: a full-length LOXL2 (fl-LOXL2) containing a nearly stoichiometric amount of LTQ, Δ1-2SRCR-LOXL2 (SRCR1 and SRCR2 are truncated) in the precursor form, and Δ1-3SRCR-LOXL2 (SRCR1, SRCR2, SRCR3 are truncated) in a mixture of the precursor and the mature forms. We detected a set of five disulfide bonds that is conserved in both the precursor and the mature recombinant LOXL2s. In addition, we detected a set of four alternative disulfide bonds in low abundance that is not associated with the mature LOXL2. These results suggest that the major set of five disulfide bonds is retained post-LTQ formation.     

Inorganic Drug‐Delivery Nanovehicle Conjugated with Cancer‐Cell‐Specific Ligand

The surface of layered double hydroxide nanoparticles, a potential drug‐delivery nanovehicle, is modified with the cancer‐cell‐specific ligand, folic acid. The surface modification is successfully accomplished through step‐by‐step coupling reactions with aminopropyltriethoxysilane and 1‐ethyl‐3‐(3‐dimethyl aminopropyl)‐carbodiimide. In order to evaluate the cancer‐cell targeting effect of folic‐acid‐grafted layered double hydroxide utilizing fluorescence‐related assay, both layered double hydroxide with and without folic acid moiety are labeled with fluorescein 5′‐isothiocyanate. The uptake of layered double hydroxide and folic acid conjugated into KB and A549 cells is visualized using fluorescence microscopy and measured by flow cytometry. Both chemical and biological assay results demonstrate that the folic acid molecules are indeed conjugated to the surface of layered double hydroxide and thus the selectivity of nanovehicles to cancer cells overexpressing folate receptors increases. In this study, it is suggested that layered double hydroxide nanoparticles can be used as drug‐delivery carriers with a targeting function due to the chemical conjugation with specific ligand.     

Synthesis of Nanohole‐Structured Single‐Crystalline Platinum Nanosheets Using Surfactant‐Liquid‐Crystals and their Electrochemical Characterization

Nanohole‐structured single‐crystalline Pt nanosheets have been synthesized by the borohydride reduction of Na₂PtCl₆ confined to the lyotropic liquid crystals (LLCs) of polyoxyethylene (20) sorbitan monooleate (Tween 80) with or without nonaethylene‐glycol (C₁₂EO₉). The Pt nanosheets of around 4–10 nm in central thickness and up to 500 nm or above in diameter have a number of hexagonal‐shaped nanoholes ∼1.8 nm wide. High‐resolution electron microscope images of the nanosheets showed atomic fringes with a spacing of 0.22 nm indicating that the nanosheets are crystallographically continuous through the nanoholed and non‐holed areas. The inner‐angle distributions for the hexagonal nanoholes indicate that the six sides of the nanoholes are walled with each two Pt (111), Pt (1 1) and Pt (010) planes. The formation mechanism of nanoholed Pt nanosheets is discussed on the basis of structural and compositional data for the resulting solids and their precursory LLCs, with the aid of similar nanohole growth observed for a Tween 80 free but oleic acid‐incorporated system. It is also demonstrated that the nanoholed Pt nanostructures loaded on carbon exhibit fairly high electrocatalytic activity for oxygen reduction reaction and a high performance as a cathode material for polymer‐electrolyte fuel cells, along with their extremely high thermostability revealed through the effect of electron‐irradiation.     

Enhancement of a WLAN-Based Internet Service

A wireless LAN (WLAN)-based Internet service, called NESPOT, of Korea Telecom (KT), the biggest telecommunication and Internet service company in Korea, has been operational since early 2002. As the numbers of subscribers and deployed access points (APs) increase, KT has been endeavoring to improve its service quality as well as the network management. In this paper, we introduce a joint effort between Seoul National University (SNU) and KT to achieve it. We have been addressing two major issues as part of the joint project thus far: (1) a unified WLAN management/maintenance tool; and (2) real-time traffic support enhancement. We present our on-going efforts as well as some preliminary results. Some issues, which need further attention for the future NESPOT service enhancement, are also introduced.The work reported in this paper was financed and supported by KT. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of KT. Youngkyu Choi is an M.S. candidate in the department of electrical engineering at Seoul National University (SNU), Seoul, Korea. He received his B.S. with honors in electrical engineering from SNU in 2002. He has a lot of project experiences related with system software development. His current research interests are the design of MAC layer from distributed system to centralized cellular system, resource management in next-generation (4G) cellular system, and mathematical analysis of system performance. He had served in the Korean Army for 3 years from 1998. Sekyu Park is a research staff at the Multimedia & Wireless Networking Lab. (MWNL), Seoul National University (SNU), Seoul, Korea. Before joining MWNL in September 2003, he was with MMC Technology, Seoul, Korea as a Research Staff for five years. His current research interests are in the area of wireless/mobile networks and embedded OS. Sunghyun Choi is an assistant professor at the School of Electrical Engineering, Seoul National University (SNU), Seoul, Korea. Before joining SNU in September 2002, he was with Philips Research USA, Briarcliff Manor, New York, USA as a Senior Member Research Staff and a project leader for three years. He received his B.S. (summa cum laude) and M.S. degrees in electrical engineering from Korea Advanced Institute of Science and Technology (KAIST) in 1992 and 1994, respectively, and received Ph.D. at the Department of Electrical Engineering and Computer Science, The University of Michigan, Ann Arbor in September, 1999. His current research interests are in the area of wireless/mobile networks with emphasis on the QoS guarantee and adaptation, resource management, wireless LAN and PAN, next-generation mobile networks, data link layer protocols, and connection and mobility management. He authored/coauthored over 45 technical papers and book chapters in the areas of wireless/mobile networks and communications. He is the technical program co-chair for ACM International Workshop on Wireless Mobile Applications and Services on WLAN Hotspots (WMASH’2004). He is currently serving on program committees of a number of leading wireless and networking conferences including IEEE INFOCOM, IEEE GLOBECOM, and IEEE VTC. He is also a guest co-editor for a special issue on “Emerging WLAN Applications and Technologies” of Wiley Wireless Communications and Mobile Computing Journal. He is an active participant and contributor of the IEEE 802.11 WLAN standardization committee. Dr. Choi was a recipient of the Korea Foundation for Advanced Studies Scholarship and the Korean Government Overseas Scholarship during 1997–1999 and 1994–1997, respectively. Go Woon Lee is a researcher at Service Development Laboratory, Korea Telecom (KT), Seoul, Korea. She received her B.S. degrees in computer science and material engineering from Korea Advanced Institute of Science and Technology (KAIST) in 1995. She was with Microsoft Korea R&D Group as a research staff in 1995. She received M.S. degree in information & communication from Kwang-Ju Institute of Science and Technology (K-JIST) in 1998. Her current research interests are in the area of wireless/mobile networks with emphasis on data link layer protocols, remote diagnosis, and wireless service management. Jaehwan Lee is a researcher at Korea Telecom (KT), Seoul, Korea. He received his B.S. and M.S. degrees in electrical engineering from Seoul National University (SNU) in 1998 and 2000, respectively. His master’s research was about estimation theory related to Global Positioning System (GPS) and image processing in robot soccer. His current research interest is to analyze and enhance the performance of wireless/mobile networks (IEEE 802.11, sensor networks and mobile ad-hoc networks) regarding QoS, energy-efficiency and high-throughput considering hand-off and inter-networking with heterogeneous networks. Before joining wireless LAN group in KT, he developed the Web-GIS (Geographical Information System) client-server system from 2000 to 2001. Hanwook Jung, Ph.D joined KT in 1985 and got his Ph.D degree with the company finalcial scholarship of KT from 1991 to 1996 at SUNY at Buffalo. His thesis is about “Wireless signal transmission over Fiber by subcarrier multiplexing” which is current heavily utilized for PCS and cellular repeater line. From 1985 to 1991, he had developed a Videotex service which is now known as Hitel. From 1996 to 1999, he developed 26GHz broadband wireless local loop system and contributed to get the license from the government. Since 1999, he has led a business model and service with wireless LAN. The KT Wi-Fi public service, “NESPOT” has 300,000 subscribers and 10,000 public hotspots. In 2003 he was promoted as an assistant vice president leading NESPOT research team to enhance KT’s broadband with 5,000,000 subscribers. His vision regarding next generation communications service is believed to be true by combining the broadband access and wireless technology including WiFi wireless LAN, UWB, and bluetooth in those areas such as wireless home-networking, device-to-device communications, and ubiqutous networking.This revised version was published online in August 2005 with a corrected cover date.     

BAAQ: an infrastructure for application integration and knowledge discovery in bioinformatics.

The emerging grid computing technologies enable bioinformatics scientists to conduct their researches in a virtual laboratory, in which they share public databases, computational tools as well as their analysis workflows. However, the development of grid applications is still a nightmare for general bioinformatics scientists, due to the lack of grid programming environments, standards and high-level services. Here, we present a system, which we named Bioinformatics: Ask Any Questions (BAAQ), to automate this development procedure as much as possible. BAAQ allows scientists to store and manage remote biological data and programs, to build analysis workflows that integrate these resources seamlessly, and to discover knowledge from available resources. This paper addresses two issues in building grid applications in bioinformatics: how to smoothly compose an analysis workflow using heterogeneous resources and how to efficiently discover and re-use available resources in the grid community. Correspondingly an intelligent grid programming environment and an active solution recommendation service are proposed. Finally, we present a case study applying BAAQ to a bioinformatics problem.     

Room Temperature Spin-Phonon Coupling in Cr2O3 Nanocrystals

In this study, nanocrystals of antiferromagnetic Cr₂O₃ are shown via Raman spectroscopy to display peculiar lattice dynamics in terms of phonon softening and the occurrence of an exceptionally strong spin-phonon coupling. This effect, which is observed to persist well above the onset of the antiferromagnetic ordering temperature, is ascribed to locally correlated spin fluctuations due to the modulation of the magnetic exchange interactions as the chromium atoms oscillate about their equilibrium position. It is found that the spin-phonon coupling strength is governed by the competing antiferromagnetic and ferromagnetic interactions, where changes in the surface spin configuration can also play a crucial role. Overall, this work proves the size dependence of the interplay between the crystalline and magnetic structures in 3D antiferromagnets varying the surface-to-volume ratio and helps establish the fundamentals for a spin-phonon coupling engineering at the nanoscale via a simple route in a very stable and easy to synthesize material. More importantly, it demonstrates the possibility of coupling phononic excitations with the magnetization dynamics at room temperature, offering a highly prospective nanomaterial for the design of novel magnonic devices.     

Engineering of Lipid Nanoparticles by the Multifunctionalization of the Surface with Amino Acid Derivatives for the Neutralization of a Target Toxic Peptide

Protein affinity reagents (e.g., antibodies) are often used for basic research, diagnostics, separations, and disease therapy. Although a lot of “synthetic” protein affinity reagents have been developed as a cost-effective alternative to antibodies, their low biocompatibility is a considerable problem for clinical application. Lipid nanoparticles (LNP) represent a highly biocompatible drug delivery agent. However, little has been reported that LNP itself works as a protein affinity reagent in living animals. Here, LNP is engineered for binding to and neutralizing a target toxic peptide in living animals by multifunctionalization with amino acid derivatives. Multifunctionalized LNP (MF-LNP) is prepared using amino acid derivative-conjugated lipids. Optimized MF-LNP exhibits nanomolar affinity to the target toxic peptide and inhibits toxic peptide-dependent hemolysis and cytotoxicity. In addition, MF-LNP captures and neutralizes the toxic peptide after intravenous injection in the bloodstream; in addition, MF-LNP does not release the toxic peptide in the accumulated organ. These results reveal the potential of using LNP as a highly biocompatible protein affinity reagent such as an antidote.