351 research outputs found
Optical conductivity of rattling phonons in type-I clathrate BaGaGe
A series of infrared-active optical phonons have been detected in type-I
clathrate BaGaGe by terahertz time-domain spectroscopy. The
conductivity spectra with the lowest-lying peaks at 1.15 and 1.80 THz are
identified with so-called rattling phonons, i.e., optical modes of the guest
ion Ba with symmetry in the oversized tetrakaidecahedral
cage. The temperature dependence of the spectra from these modes are totally
consistent with calculations based on a one-dimensional anharmonic potential
model that, with decreasing temperature, the shape becomes asymmetrically sharp
associated with a softening for the weight to shift to lower frequency. These
temperature dependences are determined, without any interaction effects, by the
Bose-factor for optical excitations of anharmonic phonons with the nonequally
spaced energy levels.Comment: 4 pages, 4 figure
Quantitative detection of 4-hydroxyequileninâDNA adducts in mammalian cells using an immunoassay with a novel monoclonal antibody
EstrogenâDNA adducts are potential biomarkers for assessing the risk and development of estrogen-associated cancers. 4-Hydroxyequilenin (4-OHEN) and 4-hydroxyequilin (4-OHEQ), the metabolites of equine estrogens present in common hormone replacement therapy (HRT) formulations, are capable of producing bulky 4-OHENâDNA adducts. Although the formation of 4-OHENâDNA adducts has been reported, their quantitative detection in mammalian cells has not been done. To quantify such DNA adducts, we generated a novel monoclonal antibody (4OHEN-1) specific for 4-OHENâDNA adducts. The primary epitope recognized is one type of stereoisomers of 4-OHENâdA adducts and of 4-OHENâdC adducts in DNA. An immunoassay with 4OHEN-1 revealed a linear doseâresponse between known amounts of 4-OHENâDNA adducts and the antibody binding to those adducts, with a detection limit of approximately five adducts/108 bases in 1 Âľg DNA sample. In human breast cancer cells, the quantitative immunoassay revealed that 4-OHEN produces five times more 4-OHENâDNA adducts than does 4-OHEQ. Moreover, in a mouse model for HRT, oral administration of Premarin increased the levels of 4-OHENâDNA adducts in various tissues, including the uterus and ovaries, in a time-dependent manner. Thus, we succeeded in establishing a novel immunoassay for quantitative detection of 4-OHENâDNA adducts in mammalian cells
Proof-of-principle experiment for laser-driven cold neutron source
The scientific and technical advances continue to support novel discoveries by allowing scientists to acquire new insights into the structure and properties of matter using new tools and sources. Notably, neutrons are among the most valuable sources in providing such a capability. At the Institute of Laser Engineering, Osaka, the first steps are taken towards the development of a table-top laser-driven neutron source, capable of producing a wide range of energies with high brightness and temporal resolution. By employing a pure hydrogen moderator, maintained at cryogenic temperature, a cold neutron (â¤25meV) flux of âź2Ă103n/cm2/pulse was measured at the proximity of the moderator exit surface. The beam duration of hundreds of ns to tens of \upmu \hbox {s}Îźsis evaluated for neutron energies ranging from 100s keV down to meV via Monte-Carlo techniques. Presently, with the upcoming J-EPoCH high repetition rate laser at Osaka University, a cold neutron flux in orders of âź1Ă109n/cm2/sis expected to be delivered at the moderator in a compact beamline
OGX-427 inhibits tumor progression and enhances gemcitabine chemotherapy in pancreatic cancer
Despite many advances in oncology, almost all patients with pancreatic cancer (PC) die of the disease. Molecularly targeted agents are offering hope for their potential role in helping translate the improved activity of combination chemotherapy into improved survival. Heat shock protein 27 (Hsp27) is a chaperone implicated in several pathological processes such as cancer. Further, Hsp27 expression becomes highly upregulated in cancer cells after chemotherapy. Recently, a modified antisense oligonucleotide that is complementary to Hsp27 (OGX-427) has been developed, which inhibits Hsp27 expression and enhances drug efficacy in cancer xenograft models. Phase II clinical trials using OGX-427 in different cancers like breast, ovarian, bladder, prostate and lung are in progress in the United States and Canada. In this study, we demonstrate using TMA of 181 patients that Hsp27 expression and phosphorylation levels increase in moderately differentiated tumors to become uniformly highly expressed in metastatic samples. Using MiaPaCa-2 cells grown both in vitro and xenografted in mice, we demonstrate that OGX-427 inhibits proliferation, induces apoptosis and also enhances gemcitabine chemosensitivity via a mechanism involving the eukaryotic translation initiation factor 4E. Collectively, these findings suggest that the combination of Hsp27 knockdown with OGX-427 and chemotherapeutic agents such as gemcitabine can be a novel strategy to inhibit the progression of pancreas cancer
<Abstract of annual report>Effects of the New Antiallergic Drug 11-Oxo-11H-Pyrido[2,1-b]quinazoline-2-carboxylic Acid on Immediate Allergic Reactions.
LAVA: An Open-Source Approach To Designing LAMP (Loop-Mediated Isothermal Amplification) DNA Signatures
<p>Abstract</p> <p>Background</p> <p>We developed an extendable open-source Loop-mediated isothermal AMPlification (LAMP) signature design program called LAVA (LAMP Assay Versatile Analysis). LAVA was created in response to limitations of existing LAMP signature programs.</p> <p>Results</p> <p>LAVA identifies combinations of six primer regions for basic LAMP signatures, or combinations of eight primer regions for LAMP signatures with loop primers, which can be used as LAMP signatures. The identified primers are conserved among target organism sequences. Primer combinations are optimized based on lengths, melting temperatures, and spacing among primer sites. We compare LAMP signature candidates for <it>Staphylococcus aureus </it>created both by LAVA and by PrimerExplorer. We also include signatures from a sample run targeting all strains of <it>Mycobacterium tuberculosis</it>.</p> <p>Conclusions</p> <p>We have designed and demonstrated new software for identifying signature candidates appropriate for LAMP assays. The software is available for download at <url>http://lava-dna.googlecode.com/</url>.</p
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