Sunday, June 24, 2012

Red-Emitting Dendritic Iridium(III) Complexes for Solution Processable Phosphorescent Organic Light-Emitting Diodes

Red-Emitting Dendritic Iridium(III) Complexes for Solution Processable Phosphorescent Organic Light-Emitting Diodes 

Tianshi Qin, Junqiao Ding, Martin Baumgarten, Lixiang Wang, Klaus Müllen*

http://onlinelibrary.wiley.com/doi/10.1002/marc.201100657/full
This paper describes an excellent approach to improving OLED performance by preventing aggregation-induced luminescence quenching. Aggregation is prevented by growing a dendrimer from an iridium-complex "nucleus."  The dendrimers were synthesized via an efficient D.A. reaction.  In general, an elegant route to complex materials.

Friedel−Crafts Acylation with Amides

Friedel−Crafts Acylation with Amides
Erum K. Raja,† Daniel J. DeSchepper,† Sten O. Nilsson Lill,‡ and Douglas A. Klumpp*,† 

http://pubs.acs.org/doi/abs/10.1021/jo300922p 

This paper describes used of activated amides as Friedel-Crafts acylation substrates, presumably going through a dicationic intermediates.

The landscape of cancer genes and mutational processes in breast cancer

The landscape of cancer genes and mutational processes in breast cancer

Philip J. Stephens et al.
http://www.nature.com/nature/journal/v486/n7403/full/nature11017.html

This report details the findings made during a search for "driver mutations," genetic mutations which are responsible for oncogenesis.

Reversible Light-Triggered Transition of Amphiphilic Random Copolymers

Ke Feng, Nan Xie, Bin Chen, Li-Ping Zhang, Chen-Ho Tung, and Li-Zhu Wu
Macromolecules

http://pubs.acs.org/doi/full/10.1021/ma300734z

The authors prepared an amphiphilic random copolymer using ROMP. One of the monomers, the spiropyran, undergoes an ultraviolet-initiated change from hydrophobic to hydrophilic. This transition is reversible on irradiation with visible light. The authors found that in solution these polymers for micelles which shrink in size (and solution changes color) upon uv irradiation. They also studied the encapsulation and release of the hydrophobic dye Nile Red, which is used as a model for drug delivery.


Facile Synthesis of Functionalized Lactones and Organocatalytic Ring-Opening Polymerization

Hyunuk Kim, Johan V. Olsson, James L. Hedrick, and Robert M. Waymouth

http://pubs.acs.org/doi/pdf/10.1021/mz3001397

An alpha-beta unsaturated valerolactone was functionalized with conjugate addition of a thiol.  Ring opening polymerization led to functionalized polyesters, but these substituted monomers underwent slower polymerization than the unfunctionalized. The group also showed copolymerization of functionalized valerolactone with caprolactone.

Abstract Image

Exploring thermal reversible hydrogels for stem cell expansion in three-dimensions

Zheyu Shen, Jingxiu Bi, Bingyang Shi, Dzuy Nguyen, Cory J. Xian,b Hu Zhang and Sheng Dai

http://pubs.rsc.org/en/Content/ArticleLanding/2012/SM/C2SM25407G?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FSM+%28RSC+-+Soft+Matter+latest+articles%29

Hydrogels were synthesized from poly(N-isopropylacrylamide-co-acrylic acid) microgels, which formed hydrogels upon heating to 37 C thus encapsulating the murine embryonic mesenchymal progenitor cell
(C3H/10T1/2). The hydrogel reverted back to microgels and cell release upon cooling. This cooling allowed recovery of the cells, which were then able to adhere to a 2D surface. Experiments were done to further characterize, image, and test cell cytotoxicity on the gels.

Graphical abstract: Exploring thermal reversible hydrogels for stem cell expansion in three-dimensions

Directed persistent motion maintains sheet integrity during multi-cellular spreading and migration

Kenechukwu David Nnetu, Melanie Knorr, Dan Strehle, Mareike Zink and Josef A. K€as

http://pubs.rsc.org/en/Content/ArticleLanding/2012/SM/C2SM07208D?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+rss%2FSM+%28RSC+-+Soft+Matter+latest+articles%29

This research group is studying the collective cell migration properties of the following cell monolayers: MCF-10A epithelial cells has weak cell-cell adherence and single cells could detach; MDA-MB-231 epithelial cells could not detach from each other; and NIH 3t3 fibroblast cells did not interact and could not migrate together. They studied the dynamics of the cell monolayers, for example, they found evidence on the heterogenity of the MCF-10A cells with the lower cell density regions having higher velocities. As well, the cells were treated with EGTA (ethylene glycol tetraacetic acid), which chelates calcium and reduces intercellular interactions. This experiment showed that even at high cell densities in which cells did not readily detach in the MCF-10A monolayer, introduction of the chelator did promote single cell detachment and monolayers could move toward the cells detached or the escaped cells could move back into the monolayer. Overall, the researchers suggest that cell dynamics plays an important role in collective cell migration and these cell-cell interactions can produce stable boundaries.
Graphical abstract: Directed persistent motion maintains sheet integrity during multi-cellular spreading and migration

Stem-cell differentiation: Anchoring cell-fate cues

Effect of collagen network structure on stem-cell fate:
http://www.nature.com/nmat/journal/v11/n7/full/nmat3366.html?WT.ec_id=NMAT-201207

Janus polymeric cages

Polymer
http://www.sciencedirect.com/science/article/pii/S0032386112004909

Oil-soluble monomers and water-soluble monomers copolymerized in between the voids among the silica particles at the interface, forming amphiphilic Janus polymer shell in which the silica particles are embedded. After removal of the silica particles and the oil core, the corresponding Janus polymeric cages are achieved with uniform and regularly arrayed holes across the shell. The Janus cages are permeable to both organic molecules and particles.






A Pickering emulsion is an emulsion that is stabilized by solid particles (for example colloidal silica or adsorbed polyelectrolytes) which adsorb onto the interface between the two phases. (From Wikipedia)