Molecular excitation in the Interstellar Medium: recent advances in collisional, radiative and chemical processes

We review the different excitation processes in the interstellar mediumComment: Accepted in Chem. Re

Imaging Immune Surveillance of Individual Natural Killer Cells Confined in Microwell Arrays

New markers are constantly emerging that identify smaller and smaller subpopulations of immune cells. However, there is a growing awareness that even within very small populations, there is a marked functional heterogeneity and that measurements at the population level only gives an average estimate of the behaviour of that pool of cells. New techniques to analyze single immune cells over time are needed to overcome this limitation. For that purpose, we have designed and evaluated microwell array systems made from two materials, polydimethylsiloxane (PDMS) and silicon, for high-resolution imaging of individual natural killer (NK) cell responses. Both materials were suitable for short-term studies (<4 hours) but only silicon wells allowed long-term studies (several days). Time-lapse imaging of NK cell cytotoxicity in these microwell arrays revealed that roughly 30% of the target cells died much more rapidly than the rest upon NK cell encounter. This unexpected heterogeneity may reflect either separate mechanisms of killing or different killing efficiency by individual NK cells. Furthermore, we show that high-resolution imaging of inhibitory synapse formation, defined by clustering of MHC class I at the interface between NK and target cells, is possible in these microwells. We conclude that live cell imaging of NK-target cell interactions in multi-well microstructures are possible. The technique enables novel types of assays and allow data collection at a level of resolution not previously obtained. Furthermore, due to the large number of wells that can be simultaneously imaged, new statistical information is obtained that will lead to a better understanding of the function and regulation of the immune system at the single cell level

Personality traits and mental disorders

Peer reviewe

Evolution of the life cycle in land plants

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92043/1/j.1759-6831.2012.00188.x.pd

Asymmetrische Synthesen über heterocyclische Zwischenstufen, V Asymmetrische Synthese von α-Methylaminosäuren durch Alkylieren des lithiierten Lactimethers von cyclo-(L-Ala-L-Ala)

The (3S,6S)-2,5-dimethoxy-3,6-dimethyl-3,6-dihydropyrazi[nlaec tim ether of cyclo-(L-Ala-LAla)] (7) is obtained from cyclo-(L-Ala-L-Ala) 5 (93 - 95% optically pure) and trimethyloxonium tetrafluoroborate. With butyllithium the lithio derivative 8 is formed which reacts with alkyl halides in good chemical yields and with more than 90% diastereoselectivity, whereby R-configuration is induced at C-3. A model concept is discussed, which explains the remarkably high asymmetric induction. - Hydrolysis (0.25 N HCI, room temp.) gives L-alanine methyl ester (4) and the (R)-a-methyl amino acid methyl esters 13. The two amino acid esters are separable by distillation or chromatography