Single-shot non-interferometric measurement of the phase transmission matrix in multicore fibers

A simple technique for far-field single-shot non-interferometric determination of the phase transmission matrix of a multicore fiber with over 100 cores is presented. This phase retrieval technique relies on the aperiodic arrangement of the cores.Comment: Submitted to Optics Letter

Protein quality control in the nucleus

In their natural environment, cells are regularly exposed to various stress conditions that may lead to protein misfolding, but also in the absence of stress, misfolded proteins occur as the result of mutations or failures during protein synthesis. Since such partially denatured proteins are prone to aggregate, cells have evolved several elaborate quality control systems to deal with these potentially toxic proteins. First, various molecular chaperones will seize the misfolded protein and either attempt to refold the protein or target it for degradation via the ubiquitin-proteasome system. The degradation of misfolded proteins is clearly compartmentalized, so unique degradation pathways exist for misfolded proteins depending on whether their subcellular localization is ER/secretory, mitochondrial, cytosolic or nuclear. Recent studies, mainly in yeast, have shown that the nucleus appears to be particularly active in protein quality control. Thus, specific ubiquitin-protein ligases located in the nucleus, target not only misfolded nuclear proteins, but also various misfolded cytosolic proteins which are transported to the nucleus prior to their degradation. In comparison, much less is known about these mechanisms in mammalian cells. Here we highlight recent advances in our understanding of nuclear protein quality control, in particular regarding substrate recognition and proteasomal degradation

Sonosensitive dioleoylphosphatidylethanolamine-containing liposomes with prolonged blood circulation time of doxorubicin

This article is part of Tove Julie Evjen's doctoral thesis, which is available in Munin at http://hdl.handle.net/10037/3373Ultrasound sensitive (sonosensitive liposomes) are drug delivery systems designed for releasing their drug load upon exposure to ultrasound (US). Inclusion of dioleoylphosphatidylethanolamine (DOPE) in liposome membranes was previously shown to induce sonosensitivity. For efficient US mediated drug delivery to solid tumours, a long blood circulation time of the liposomal drug providing high tumour uptake is required. In this study, blood pharmacokinetics of DOPE-based liposomal doxorubicin (DXR) were evaluated in mice. A markedly faster blood clearance of DXR was observed for DOPE-rich liposomes compared to Caelyx! (standard liposomal DXR). Subsequently, liposome membrane composition was altered to improve drug retention in the bloodstream, while maintaining sonosensitivity. Formulations with reduced blood clearance of DXR were obtained by reducing the content of DOPE from 62 to 32 or 25 mol%. These formulations showed long blood circulation time, as approximately 20% of the administered DXR dose was present in the bloodstream 24 h after intravenous injection. The reduction in liposomal DOPE content did not significantly reduce US mediated DXR release in vitro, indicating that DOPE is a potent modulator to sonosensitivity. The novel liposome formulations, containing moderate amounts of DOPE, displayed similar blood pharmacokinetic profiles as standard liposomal DXR, but a markedly improved sonosensitivity

Hyperfine-Structure-Induced Depolarization of Impulsively Aligned I2\rm I_2 Molecules

A moderately intense $450$ fs laser pulse is used to create rotational wave packets in gas phase $\rm{I_2}$ molecules. The ensuing time-dependent alignment, measured by Coulomb explosion imaging with a delayed probe pulse, exhibits the characteristic revival structures expected for rotational wave packets but also a complex non-periodic substructure and decreasing mean alignment not observed before. A quantum mechanical model attributes the phenomena to coupling between the rotational angular momenta and the nuclear spins through the electric quadrupole interaction. The calculated alignment trace agrees very well with the experimental results.Comment: 6 pages, 4 figures, and Supplementary Information. This article has been accepted for publication in Physical Review Letter