1,508 research outputs found
Application of Subcritical Water Hydrolysate from Thermosetting Polyester Resin to Aqueous Agents
Thermosetting polyester resin used in fiber reinforced plastic (FRP) is very difficult to be recycled since it cannot be re-molded like thermoplastic resin. In recycling thermosetting polyester resin, subcritical water with alkali was applied to hydrolyze ester bonds to obtain styrene-fumaric acid copolymer (SFC). SFC, subcritical water hydrolysate from thermosetting polyester resin, has a molecular structure of functional polymer. Alkali salt of the SFC has a same molecular structure as alkali salt of styrene-maleic anhydride copolymer (SMA) which is widely used in various kinds of high performance additives for aqueous applications. In these applications, dispersing agent, detergent builder, and surface sizing agent were selected for application of alkali salt of the SFC . The reaction product liquid contains sodium salt of SFC (SFC-Na). It was evaluated as dispersing agent and detergent builder. Ammonium salt of SFC (SFC-NH4) was evaluated as surface sizing agent for paper. The evaluation results were compared with that of commercial additives to verify the possibility to substitute them. The reaction product liquid showed superior dispersing effect to commercial dispersing agent for hydrophobic powder. It also showed superior alkali buffering capacity to commercial detergent builder. SFC-NH4 showed higher sizing effect than commercial sizing agent
Infrared Spectroscopy of CO Ro-vibrational Absorption Lines toward the Obscured AGN IRAS 08572+3915
We present high-resolution spectroscopy of gaseous CO absorption in the
fundamental ro-vibrational band toward the heavily obscured active galactic
nucleus (AGN) IRAS 08572+3915. We have detected absorption lines up to highly
excited rotational levels (J<=17). The velocity profiles reveal three distinct
components, the strongest and broadest (delta_v > 200 km s-1) of which is due
to blueshifted (-160 km s-1) gas at a temperature of ~ 270 K absorbing at
velocities as high as -400 km s-1. A much weaker but even warmer (~ 700 K)
component, which is highly redshifted (+100 km s-1), is also detected, in
addition to a cold (~ 20 K) component centered at the systemic velocity of the
galaxy. On the assumption of local thermodynamic equilibrium, the column
density of CO in the 270 K component is NCO ~ 4.5 x 10^18 cm-2, which in fully
molecular gas corresponds to a H2 column density of NH2 ~ 2.5 x 10^22 cm-2. The
thermal excitation of CO up to the observed high rotational levels requires a
density greater than nc(H2) > 2 x 10^7 cm-3, implying that the thickness of the
warm absorbing layer is extremely small (delta_d < 4 x 10-2 pc) even if it is
highly clumped. The large column densities and high radial velocities
associated with these warm components, as well as their temperatures, indicate
that they originate in molecular clouds near the central engine of the AGN.Comment: 13 pages, 7 figures, accepted for publication in PASJ (Vol.65 No.1
2013/02/25
Production of Ultrahigh Magnetic Fields by Explosive-Driven Flux Compression
Magnetic fields exceeding 1 MOe are reproducibly generated by a flux compression method using a cylindrical metal liner and high explosives. Some new devices are employed for simultaneous initiation of the cylindrical explosive on its outer surface. Detailed measurements are made on the dependence of the liner velocity on the mass ratio of liner and explosive. The results are consistent with an analysis based on the theory of detonation
High-Sensitivity Streak Camera Applicable to Time-Resolved Spectroscopy
A high-sensitivity streak camera has been designed and manufactured using a photoelectric tube with deflecting plates and a microchannel plate which serves as both a streak device and an image intensifier. Characteristics of the complete equipments are as follows : (1) an image on the film is 10.2 times as large as an image on the photoelectric surface, (2) effective area of the film is 45 mm in diameter, (3) resolution on the film is 2.5 lp/mm (4) writing speed on the film is 0.2~20 mm/μs, 5-stage variable, (5) sensitivity is controlled by the microchannel plate voltage, and (6) a spectroscope is combined to take time-resolved spectrographs, 1 mm on the film corresponding to 0.9 nm of the wavelength
Shock Compression Experiments in Solids using High Explosives
Small-scale explosive plane wave generators, 40-78 mm in diameter, are developed to perform solid state experiments at shock pressures up to 1 Mbar. Techniques for determining the shock compression curve are described in detail, especially in the case where a phase transformation occurs at a high pressure
Formation of Diaplectic Glass in Anorthite by Shock-Loading Experiments(Physics)
Shock-recovery experiments on primitive anorthite have been carried out in which single crystals of anorthite are shocked to peak pressures of 150, 300, and 380 kbar, and the recovered specimen is examined by means of electron microscopy. Diaplectic glass is observed in specimens shocked above 300 kbar, and the specimen shocked to 380 kbar is found to be completely converted to diaplectic glass. In fragments shocked to 300 kbar, the intergrowth textures of diaplectic glass and anorthite crystal are observed under an electron microscope. The diffuseness of b reflections in the electron diffraction pattern of intergrown crystals has no noticeable change in comparison with that of the starting specimen. The results indicate that the original configuration of antiphase domains is retained in the shocked crystal until an abrupt transition of primitive anorthite to diaplectic glass occurs. Diaplectic glass is supposed to be produced secondarily from an unquenchable high-pressure form induced under shock loading
Shock Compression of Titanium Monoxide up to 600 kbar(Physics)
Hugoniot data were obtained for titanium monoxide TiO_x (x=0.84, 1.06, and 1.28), up to about 600 kbar by shock wave compression. A small explosive lens system was used for the purpose of generating plane shock waves. Shock velocities and free surface velocities were measured by means of an electric pin-contactor method ; the shock state was computed on the basis of free surface approximation. Regardless of the values of x, the compounds TiO_x were shown to be extremely incompressible even in this ultrahigh pressure region ; no evidence was found for significant filling of vacancies
Triethylated chromones with substituted naphthalenes as tubulin inhibitors
Previously synthesized 2-(benzo[]thiophene-3′-yl)-6,8,8-triethyldesmosdumotin B (, TEDB-TB) and 2-(naphth-1′-yl)-6,8,8-triethyldesmosdumotin B () showed potent activity against multiple human tumor cell lines, including a multidrug-resistant (MDR) subline, by targeting spindle formation and/or the microtubule network. Consequently, ester analogues of hydroxylated naphthyl substituted TEBDs (–) were prepared and evaluated for their effects on tumor cell proliferation and on tubulin assembly. Among all new compounds, compound , a 4′-acetoxynaphthalen-1′-yl derivative, displayed the most potent antiproliferative activity (IC 0.2–5.7 μM). Selected analogues were confirmed to be tubulin assembly inhibitors in cell-free and cell-based assays using MDR tumor cells. The new analogues partially inhibited colchicine binding to tubulin, suggesting their binding mode would be different from that of colchicine. This observation was supported by computational docking model analyses. Thus, the newly synthesized triethylated chromones with esterified naphthalene groups have good potential for development as a new class of mitotic inhibitors that target tubulin
Phytoagent deoxyelephantopin derivative inhibits triple negative breast cancer cell activity by inducing oxidative stress-mediated paraptosis-like cell death
Triple negative breast cancer (TNBC) is a highly metastatic cancer among the breast cancer subgroups. A thorny issue for clinical therapy of TNBC is lack of an efficient targeted therapeutic strategy. We previously created a novel sesquiterpene lactone analog (named DETD-35) derived from plant deoxyelephantopin (DET) which exhibits potent effects against human TNBC MDA-MB-231 tumor growth in a xenograft mouse model. Here we studied the mechanisms of both DET and DETD-35 against MDA-MB-231 cells. DETD-35 (3-fold decreased in IC50) exhibited better anti-TNBC cell activity than DET as observed through induction of reactive oxygen species production (within 2 h treatment) and damage to the ER structures, resulting in ER-derived cytoplasmic vacuolation and ubiquitinated protein accumulation in the treated cells. Intriguingly, the effects of both compounds were blockaded by pretreatment with ROS scavengers, N-acetylcysteine and reduced glutathione, and protein synthesis inhibitor, cycloheximide. Further, knockdown of MEK upstream regulator RAF1 and autophagosomal marker LC3, and co-treatment with JNK or ERK1/2 inhibitor resulted in the most significant attenuation of DETD-35-induced morphological and molecular or biochemical changes in cancer cells, while the inhibitory effect of DET was not influenced by MAPK inhibitor treatment. Therefore, DETD-35 exerted both ER stress-mediated paraptosis and apoptosis, which may explain its superior activity to DET against TNBC cells. Although the chemotherapeutic drug paclitaxel induced vacuole-like structures in MDA-MB-231 cells, no paraptotic cell death features were detected. This study provides a strategy for combating TNBC through sesquiterpene lactone analogs by induction of oxidative and ER stresses that cause paraptosis-like cell death
A Novel Plant Sesquiterpene Lactone Derivative, DETD-35, Suppresses BRAF V600E Mutant Melanoma Growth and Overcomes Acquired Vemurafenib Resistance in Mice
Acquired resistance to vemurafenib develops through reactivation of RAF/MEK/ERK signaling or bypass mechanisms. Recent combination therapies such as a MEK inhibitor combined with vemurafenib show improvement in major clinical end points but the percentage of patients with adverse toxic events is higher than with vemurafenib monotherapy and most patients ultimately relapse. Therefore, there is an urgent need to develop new anti-melanoma drugs and/or adjuvant agents for vemurafenib therapy. In this study, we created a novel semi-organically modified derivative, DETD-35, from deoxyelephantopin (DET), a plant sesquiterpene lactone demonstrated as an anti-inflammatory and anti-mammary tumor agent. Our results show that DETD-35 inhibited proliferation of a panel of melanoma cell lines, including acquired vemurafenib resistance A375 cells (A375-R) established in this study, with superior activities to DET and no cytotoxicity to normal melanocytes. DETD-35 suppressed tumor growth and reduced tumor mass as effectively as vemurafenib in A375 xenograft study. Furthermore, DETD-35 also reduced tumor growth in both acquired (A375-R) and intrinsic (A2058) vemurafenib resistance xenograft models, where vemurafenib showed no anti-tumor activity. Notably, the combination of DETD-35 and vemurafenib exhibited the most significant effects in both in vitro and in vivo xenograft studies due to synergism of the compound and the drug. Mechanistic studies suggested that DETD-35 overcame acquired vemurafenib resistance at least in part through deregulating MEK-ERK, Akt, and STAT3 signaling pathways and promoting apoptosis of cancer cells. Overall, our results suggest that DETD-35 may be useful as a therapeutic or adjuvant agent against BRAFV600E mutant and acquired vemurafenib resistance melanoma
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