5,452 research outputs found
Functional analysis of "MEMO / MHO1", an evolutionary conserved gene, in yeast and mammalian cells
No full textThe protein Memo (Mediator of ErbB2 driven cell motility) was identified in a screen for ErbB2 receptor tyrosine kinase (RTK) interacting proteins that have roles in cancer cell motility. A single Memo protein of 297 amino acids is encoded in the human genome. Memo is evolutionarily conserved and homologs are found in all branches of life. The human and the yeast protein share an identity of more than 40% and a similarity of more than 50%. Memo is not homologous to any known signaling proteins and based on its conservation we expect it to have functions in addition to promoting motility in response to RTK activation. In the work described here, we used the model organism S. cerevisiae to characterize Mho1 (Yjr008wp) and to investigate its function in yeast. MHO1 expression is strongly induced in conditions of stress. In stationary phase, one stress condition, a high percentage of Memo is present in the nucleus. In mammalian cells, Memo is also found throughout the cell. Memo has no obvious NLS (nuclear localization sequence), however, an NES (nuclear export sequence) is present in all Memo homologs. In mammalian cells, blocking nuclear export with Leptomycin B led to nuclear Memo accumulation, suggesting that it is actively exported from the nucleus. Since invasive growth in S. cerevisiea can be induced by stress, e.g., nitrogen deprivation, or alcohol induced, we tested the role of Mho1 in this response. Deletion of MHO1 had no effect on the formation of pseudohyphoa or invasion. Growth of mho1Δ cells was not affected by stress inducers including (HU, CoCl2, Heat-shock, Latrunculin, Nocodazol). Interestingly, however, overexpression of Mho1 blocked the ability of the yeast cells to invade. In a synthetic lethal (SL) screen we found MHO1 as a novel SL partner of PLC1. Plc1 is the only phospholipase C in yeast and hydrolyzes phosphatidylinositol 4,5-biphosphate (PIP2) to generate the signaling molecules inositol 1,4,5-triphosphate (IP3) and 1,2-diacylglycerol (DAG). In the absence of MHO1 and PLC1, double deleted spores still germinate but proliferation is impaired after 2 to 10 cell cycles by an unknown mechanism. Introduction of human MEMO into the memoΔplc1Δ strain could rescue the SL phenotype showing that the specific function of Mho1/Memo needed to overcome the synthetic lethal phenotype is conserved
Mode transformer for miniaturized optical circuits
No full textA novel mode transformer was fabricated that transforms a modal area by a factor of 100. Using the mode transformer improves the efficiency of mode transformation by an order of magnitude compared with that when no mode transformer is used. With this mode transformer, input-output coupling of miniaturized, on-chip integrated optical circuits to external optical fibers is achieved with low loss. The mode transformer's design, fabricated in silicon, is scalable to virtually any waveguide size, facilitating continuous miniaturization in silicon optoelectronics. (C) 2005 Optical Society of America
Observation of the Λ b 0 → J / ψ Ξ - K + decay
No full textAbstract Using proton–proton collision data corresponding to an integrated luminosity of 140 fb - 1 collected by the CMS experiment at s = 13 Te V , the Λ b 0 → J / ψ Ξ - K + decay is observed for the first time, with a statistical significance exceeding 5 standard deviations. The relative branching fraction, with respect to the Λ b 0 → ψ ( 2 S ) Λ decay, is measured to be B ( Λ b 0 → J / ψ Ξ - K + ) / B ( Λ b 0 → ψ ( 2 S ) Λ ) = [ 3.38 ± 1.02 ± 0.61 ± 0.03 ] % , where the first uncertainty is statistical, the second is systematic, and the third is related to the uncertainties in B ( ψ ( 2 S ) → J / ψ π + π - ) and B ( Ξ - → Λ π - )
Seasonal oscillations in length-of-day Paper
No full textVariations of annual and semiannual oscillations in rotation parameters have been investigated on the basis of Length-Of-Day (LOD) as well as Atmospheric-Angular-Momemtum (AAM) series. These oscillations were determined using band-pass filters. In order to show the character of variations of seasonal oscillations, amplitudes, phases and periods were computed by a least-squares adjustment with the method of modified harmonic analysis at quarterly intervals. In addition, the seasonal imbalances in LOD and AAM budgets were determined and analysed in a similar way. These discrepancies were corrected for tidally excited effects. The non-atmospheric oscillations without the annual tide effect Sa and the semiannual tide effect Ssa have changeable amplitudes between 0.02 and 0.10 msec. (orig.)SIGLEAvailable from TIB Hannover: RR 6134(96/03) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
Interannual variations in length-of-day and atmospheric-angular-momentum with respect to ENSO cycles
No full textAt interannual time scales, the excitation of variations in Length-Of-Day (LOD) is caused by two prominent signals in the atmosphere: The El Nino-Southern oscillation (ENSO) and the Quasi-Biennial Oscillation (QBO). In this study, the axial Atmospheric-Angular-Momentum (AAM) component _#chi#_3 is related to changes in LOD. Focussing on the interannual variations in the solid Earth-atmosphere axial angular momentum budges, we consider the Low-Frequency Component and the Quasi-Biennial Oscillation in LOD and AAM in their temporal variability. In particular, we use the time series of LOD data of the series EOP (IERS) 97C04 from 1962 to 1998 and of _#chi#_3 data of the series AAM (NCEP) Reanalysis from 1958 to 1998, AAM (JMA) from 1983 to 1998, AAM (ECMWF) from 1988 to 1996, and AAM (UKMO) from 1986 to 1998. To separate the interannual signals, we apply low-pass and band-pass filters. For comparison, the monthly data of the Southern Oscillation Index (SOI), as given by the NOAA as the difference in the surface pressure between Tahiti and Darwin, Australia, are processed and exhibited in the same manner. The main results are quantitative estimates of the Low-Frequency Component and the Quasi-Biennial Oscillation in the LOD, AAM and SOI variations and of the total interannual signals in the AAM and SOI variations. Also, the decadal LOD component is available as a function of time. (orig.)Available from TIB Hannover: RR 6134(99/07) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
The CMS Muon System and Its Performance in the CMS Cosmic Challenge
No full textThis article describes the CMS muon system and its performance in a first CMS global run using cosmic ray muons
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