https://www.uni-lj.si/mma/biomedicina%20Macek%20Influenza%20virus%20budding/2013090613550890/

Influenza virus assembly and budding.

Influenza Virus M2 Protein Mediates ESCRT-Independent Membrane Scission

The Interferon-Inducible Protein Viperin Inhibits Influenza Virus Release by Perturbing Lipid Rafts

https://escholarship.org/content/qt7548q7cp/qt7548q7cp.pdf?t=qaem19

Assembly and budding of influenza virus.

We derive a stochastic nonlinear continuum theory to describe the morphological evolution of amorphous surfaces eroded by ion bombardment. Starting from Sigmund's theory of sputter erosion, we calculate the coefficients appearing in the continuum equation in terms of the physical parameters characterizing the sputtering process. We analyze the morphological features predicted by the continuum theory, comparing them with the experimentally reported morphologies. We show that for short time scales, where the effect of nonlinear terms is negligible, the continuum theory predicts ripple formation. We demonstrate that in addition to relaxation by thermal surface diffusion, the sputtering process can also contribute to the smoothing mechanisms shaping the surface morphology. We explicitly calculate an effective surface diffusion constant characterizing this smoothing effect, and show that it is responsible for the low temperature ripple formation observed in various experiments. At long time scales the nonlinear terms dominate the evolution of the surface morphology. The nonlinear terms lead to the stabilization of the ripple wavelength and we show that, depending on the experimental parameters such as angle of incidence and ion energy, different morphologies can be observed: asymptotically, sputter eroded surfaces could undergo kinetic roughening, or can display novel ordered structures with rotated ripples. Finally, we discuss in detail the existing experimental support for the proposed theory, and uncover novel features of the surface morphology and evolution, that could be directly tested experimentally.

Morphology of Ion-Sputtered Surfaces

Transient phenomena initiating phase transition in dilution refrigerator

The application of electromagnetically induced transparency (EIT) in high speed optical switching has remained as a key topic in research related to all optical switching. Demonstration of optical switching through EIT realized under ladder (Ξ) level coupling has been reported earlier. Due to narrow linewidth ( Г EIT ) and low coherent dephasing rate ( γ ) the EIT needs to be prepared only once to demonstrate such switching action. However, in a Ξ system the EIT is accompanied with double resonance optical pumping (DROP) signal, which is limited by spontaneous decay ( Г ) rates. It has been shown by our group that the simultaneous presence of DROP–EIT combination paves the way for executing a kind of slow–fast switching action. However the focus always remain on improving the modulation depth in such type of coherence assisted switch. Here we report a possible way to improve modulation depth by using an additional (named ‘repumping’ after convention used in laser cooling experiments) laser in the Ξ system. The 5S 1/2 →5P 3/2 →5D 5/2 level coupling scheme of 87 Rb atom is used in the current experiment.

Application of repumping laser in optical switching

Synthesis and positron characterizations of ferromagnetic Zn0.98Mn0.02O and paramagnetic Zn0.98Mn0.02O samples

The cumulative yields for 13 short-lived neutron rich nuclei in the mass rangeA=99 toA=118, produced via the232Th (α, f) reaction were determined at four incident beam energies covering the range from 28 to 72 MeV usingγ-spectroscopy of fission products. The charge distribution parameter Z p was determined for theA=99 mass chain at all the four incident beam energies of 28.5, 39.7, 50.8 and 71.4 MeV and was found to fit into a description of fission process with unchanged charge division (UCD). The measured cumulative yields were converted into chain yields assuming UCD and the yieldmass distribution was obtained at all the above energies. The mass distribution remains asymmetric even at 71.4 MeV, the highest energy studied in this work. The excitation energy dependence of the mass and the charge distribution and of the cumulative yields indirectly suggests that the fission has predominantly proceeded from a relatively low level of excitation allowing most of the excitation energy to be carried away by light particles prior to scission.

Mass and charge distribution in232Th(α, f) reaction in the projectile energy range 28 to 72 MeV

The production of intermediate-mass fragments ranging from Z=3 to 8 emitted in the reaction of 60 MeV alpha on an aluminum target has been experimentally studied. The energy spectra of the emitted fragments in the angular range of 20\ifmmode^\circ\else\textdegree\fi{}\char21{}130\ifmmode^\circ\else\textdegree\fi{} have been measured and the total production cross sections of each fragment have been estimated from the data. The double-differential cross-section data have been compared with the predictions made using (a) a phenomenological moving source model and (b) a binary fragmentation model. The absolute total emission cross sections for various fragments have been calculated assuming the statistical decay of a fully equilibrated compound nucleus and have been compared with the corresponding experimental estimates. It is found that the exit-channel deformation plays a significant role in the estimation of the Coulomb barrier of the separating nuclei. A theoretical procedure for the estimation of the exit-channel Coulomb barrier for the deformed system has been incorporated in the present calculation.

Alok Chakrabarti

Papers

Transient phenomena initiating phase transition in dilution refrigerator

Application of repumping laser in optical switching

Synthesis and positron characterizations of ferromagnetic Zn0.98Mn0.02O and paramagnetic Zn0.98Mn0.02O samples

Mass and charge distribution in232Th(α, f) reaction in the projectile energy range 28 to 72 MeV

Heavy fragment emission in alpha-induced reactions on aluminum at 60 MeV.