10,559 research outputs found
TACC3-ch-TOG track the growing tips of microtubules independently of clathrin and Aurora-A phosphorylation
Full text linkThe interaction between TACC3 (transforming acidic coiled coil protein 3) and the microtubule polymerase ch-TOG (colonic, hepatic tumor overexpressed gene) is evolutionarily conserved. Loading of TACC3–ch-TOG onto spindle microtubules requires the phosphorylation of TACC3 by Aurora-A kinase and the subsequent interaction of TACC3 with clathrin to form a microtubule binding surface. Whether there is a pool of TACC3–ch-TOG that is independent of clathrin in human cells, and what is the function of this pool, are open questions. Here, we report that TACC3 is recruited to the plus-ends of microtubules by its association with ch-TOG and that this pool is independent of phosphorylation and binding to clathrin. The plus-end binding of TACC3–ch-TOG persists in interphase and we propose that one cellular function of TACC3–ch-TOG is to modulate cell migration. We also describe the distinct subcellular pools of TACC3, ch-TOG and clathrin. TACC3 is often described as a centrosomal protein, but we show that there is no significant population of TACC3 at centrosomes. The delineation of distinct protein pools reveals a simplified view of how these proteins are organized and controlled by post-translational modification
Four-week inhalation toxicity, mutagenicity and immunotoxicity studies of Keum-Yeon-Cho (NosmoQ), tobacco substitute composition, in mice
No full textSafety of Kcum-Yeon-Cho (NosmoQ), a tobacco substitute composition, was evaluated in terms of acute- and 4,weeks repeated-inhalation toxicity, mutagenicity, and immunotoxicity using Balb/e mice. The air inside the inhalation chamber was collected and analyzed by GC-MS. In acute inhalation toxicity test, male and female mice were exposed to 40 Keum-Yeon-Cho cigarettes, The 50% lethal concentration (LC50) of NosmoQ was considered to be much higher than 40 cigarettes in both sexes. In 4-week repeated inhalation toxicity test, male and female mice were exposed for 6 h/day, 5 days/week for 4 weeks to 10 and 20 cigarettes per day, while control mice ere exposed to Filtered air. Our data indicated that no observed adverse effect level (NOAEL) of Keuna-Yeon-Cho should be over 20 cigarettes per day. Results of Salmonella typhimarium reversion assay with/without histidine moiety, in vivo chromosomal aberration and in vivo micronucleus assays using mouse bone marrow cells revealed that Kcum-Yeon-Cho has 110 mutagenicity. Evaluation of peripheral cellular immunity of mice treated with Keum-yeong-Cho using in vitro lymphocyte proliferation assay showed no significant difference in mean stimulation index (SI) between mice exposed to Keum-Yeon-Cho and control mice. Mean CO concentrations and total particulate matter contents of 10 and 20 cigarettes were 21.1 +/- 1.23 and 40.7 +/- 1.21 ppm (mean +/-S.D.. it = 5). and 25.7+/-3.09 and 59.0+/-4.0 mg dry weight (mean +/-S.D., n = 5), respectively. Although at negligible concentration (less than ppb level) several polycyclic aromatic hydrocarbons (PAHs) were also detected, these results indicate that NosmoQ has no toxic effect on mice. (C) 2002 Elsevier Science B.V. All rights reserved.N
An Investigation of CH- and CHO-bearing Molecules with the ROSINA-DFMS
No full textThe purpose of this work was the analysis of comet 67P/Churyumov-Gerasimenko with
regards to CH- and CHO-bearing molecules. By studying these complex organics clues
about the origin of the cometary material and the formation of the Solar System can be
derived.
In order to archive this, first a calibration campaign of the ROSINA-Double Focusing
Mass Spectrometer (DFMS) on CH- and CHO-bearing molecules was performed. The
goal was to reproduce the fragmentation patterns generated by the molecules of interest
inside the ion source of the instrument, as well as to investigate the impact on the
instrument’s sensitivity on the molecules. The study was conducted using the prevalent
DFMS operational settings of 200 μA filament emission and 45 eV ionization energy, in
combination with a multichannel plate (MCP) as detector.
The results have been combined with data collected from comet 67P/Churyumov-
Gerasimenko, in order to obtain the first detailed identification and quantification
campaign of the CH- and CHO-bearing molecules in its coma. In such way the cometary
bulk abundances could be derived for many organic molecules. This has been repeated
at altered mission phases, to determine the impact of location, season, and heliocentric
distance on the results. The outcome was summarized in two publications, which are
included in this work.
The work is organized as follows: The first chapter gives a brief overview on the Rosetta
mission and its target, comet 67P/Churyumov-Gerasimenko. The next chapter looks at
the ROSINA-DFMS. This also includes the DFMS data analysis. The third chapter
concentrates on comets in general. Chapter 4 discusses the DMFS calibration procedure
in detail. The results of the calibration campaign can be found in chapter 5. In addition,
chapter 6 shows the results of the DFMS space data analysis, including two publications
and a further comparison of the results to other comets and the interstellar medium.
Chapter 7 provides a conclusion and outlook. An appendix and a full list of references
are included at the end of this work
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Photodissociation spectroscopy and dynamics of the vinoxy (CH{sub 2}CHO) radical
No full textThe photodissociation spectroscopy and dynamics of the vinoxy (CH{sub 2}CHO) radical have been studied using fast beam photofragment translational spectroscopy. The photodissociation cross section over the B{sup 2}A{double_prime} {l_arrow} X{sup 2}A{double_prime} band is measured, and photofragment translational energy and angular distributions are obtained at several excitation energies. For CH{sub 2}CHO, predissociation is observed over the entire band, including several transitions near the band origin which were seen previously in laser-induced fluorescence experiments. Two dissociation channels are seen: CH{sub 3} + CO and H + CH{sub 2}CO. The CH{sub 3} + CO channel was investigated in considerable detail and appears to proceed via internal conversion to the CH{sub 2}CHO ground state followed by isomerization to CH{sub 3}CO and subsequent dissociation. The translational energy distributions for this channel suggest an isomerization barrier in the range of 2 eV with respect to CH{sub 3} + CO products
OBSERVATION OF VIBRATIONALLY HOT CHCHO IN THE 351NM PHOTODISSOCIATION OF XCHCHONO (X=F,Cl,Br,OH)
No full textAuthor Institution: Laser Spectroscopy Facility, Department of Chemistry, The Ohio State University, 120 W. 18th Avenue, Columbus OH 43210Alkyl nitrites have been used in the past as precursors for producing alkoxy radicals which are important intermediates in combustion and atmospheric chemistry. Substituted alkoxies, particularly hydroxy substituted alkoxy radicals, are important intermediates in the atmospheric chemistry of alkenes. In this talk we will present results obtained from the 351nm photodissociation of XCHCHONO (X=F,Cl,Br,OH). The resulting photo-fragments were probed by laser induced fluorescence (LIF) technique downstream of a free-jet expansion. We were not able to observe any transitions resulting from the corresponding XCHCHO radicals except for FCHCHONO. We were able to observe HCHO and also vibrationally hot CHCHO from all the different precursors. In CHCHO, there is a significant excitation in the CC torsion and CCO bend vibrations. There is also some excitation in CC stretching and CH rock vibrations. HCHO is produced due to dissociation of XCHCHO in the ground state as the CC scission energy is less than the available photon energy
Development of new vanadium-based oxide catalysts for decomposition of chlorinated aromatic pollutants
No full textSupported transition metal oxides and vanadium-containing multi-metallic oxides were investigated to develop new catalysts for the catalytic destruction of highly toxic polychlorinated aromatic pollutants such as polychlorinated benzenes, polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and/or biphenyls (PCBs) from waste gases. The decomposition of 1,2-dichlorobenzene (Cl(2)Bz) was chosen as a model reaction. Titanic-supported vanadium catalyst (VOx/TiO2) showed the highest activity and stability among the binary oxides tested even in the presence of water vapor. The optimum loading of vanadia was 5 wt %, corresponding to half a monolayer, suggesting that the active species are tetrahedral vanadyl species on titanic. Characterizations of the VOx/TiO2 catalysts were carried out with XRD, laser Roman spectroscopy, and TPR. Multi-metallic VOx/TiO2 catalysts prepared by incorporating Mo, W, or Cr showed enhanced activities for Cl(2)Bz oxidation. Among the tested catalysts, V-Mo-O-x/TiO2 catalysts wash-coated on the cordierite honeycomb showed a good activity for the decomposition of the toxic PCDDs/PCDFs in the flue gas emitted from a municipal solid waste incinerator (MSWI)
Hierarchical reduction and partition of hypergraph
No full textIn this paper, a hierarchical reduction method of hypergraphs is proposed. A macro-vertex in a reduced hypergraph corresponds to an edge of the original hypergraph, and thus a reduced hypergraph can provide a partition of a system. The reduction is realized by the iterations and the sequence of hierarchical reduction gives a sequence of hierarchical partitions. The proposed method allows to reduce and decompose the complexity of the system represented by hypergraphs
Kinetics of CH₂OO reactions with SO₂, NO₂, NO, H₂O and CH₃CHO as a function of pressure
Full text linkKinetics of CH₂OO Criegee intermediate reactions with SO₂, NO₂, NO, H₂O and CH₃CHO and CH₂I radical reactions with NO₂ are reported as a function of pressure at 295 K. Measurements were made under pseudo-first-order conditions using flash photolysis of CH₂I₂–O₂–N₂ gas mixtures in the presence of excess co-reagent combined with monitoring of HCHO reaction products by laser-induced fluorescence (LIF) spectroscopy and, for the reaction with SO₂, direct detection of CH₂OO by photoionisation mass spectrometry (PIMS). Rate coefficients for CH₂OO + SO₂ and CH₂OO + NO₂ are independent of pressure in the ranges studied and are (3.42 ± 0.42) × 10‾¹¹ cm³ s‾¹ (measured between 1.5 and 450 Torr) and (1.5 ± 0.5) × 10‾¹² cm³ s‾¹ (measured between 25 and 300 Torr), respectively. The rate coefficient for CH₂OO + CH₃CHO is pressure dependent, with the yield of HCHO decreasing with increasing pressure. Upper limits of 2 × 10−13 cm³ s‾¹ and 9 × 10−17 cm³ s‾¹ are placed on the rate coefficients for CH₂OO + NO and CH₂OO + H₂O, respectively. The upper limit for the rate coefficient for CH₂OO + H₂O is significantly lower than has been reported previously, with consequences for modelling of atmospheric impacts of CH₂OO chemistry
A strong temperature dependent hole direct tunneling current in p+ gate/pMOSFET with ultra-thin gate oxide
No full textCho-ch-san.
No full textGift of Dr. Mary Jane Esplen.Piano vocal [instrumentation]Cho Cho San was a maid of Japan [first line]Flow'r of old Japan I'll return again [first line of chorus]F major [key]Moderato [tempo]Popular song [form/genre]Woman [illustration]F R [engraver]Publisher's advertisement on back cover [note
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