Extracellular matrix functionalized microcavities to control hematopoietic stem and progenitor cell fate

Polymeric microcavities functionalized with extracellular matrix components were used as an experimental in vitro model to investigate principles of hematopoietic stem and progenitor cell (HSPC) fate control. Using human CD133+ HSPC we could demonstrate distinct differences in HSPC cycling and differentiation dependence on the adhesion ligand specificity (i.e., heparin, collagen I) and cytokine levels. The presented microcavity platform provides a powerful in vitro approach to explore the role of exogenous cues in HSPC fate decisions and can therefore be instrumental to progress in stem cell biology and translational research toward new therapies.     

Light-generated paramagnetic intermediates in BLUF domains

Blue-light sensitive photoreceptory BLUF domains are flavoproteins, which regulate various, mostly stress-related processes in bacteria and eukaryotes. The photoreactivity of the flavin adenine dinucleotide (FAD) cofactor in three BLUF domains from Rhodobacter sphaeroides, Synechocystis sp. PCC 6803 and Escherichia coli have been studied at low temperature using time-resolved electron paramagnetic resonance. Photoinduced flavin triplet states and radical-pair species have been detected on a microsecond time scale. Differences in the electronic structures of the FAD cofactors as reflected by altered zero-field splitting parameters of the triplet states could be correlated with changes in the amino-acid composition of the various BLUF domains' cofactor binding pockets. For the generation of the light-induced, spin-correlated radical-pair species in the BLUF domain from Synechocystis sp. PCC 6803, a tyrosine residue near the flavin's isoalloxazine moiety plays a critical role.     

Interferometric measurement of injection nozzles using ultra-small fiber-optical probes

The measurement of boreholes with diameters smaller than 500 μm is a demanding task that cannot be performed using state-of-the-art production metrology. In this letter, a miniaturized fiber probe with a diameter of 80 μm is presented. A probe is used for low-coherence interferometry to conduct highly precise measurements of form deviations of small boreholes. Measurements conducted in nozzles are also presented. The results prove the potential of the fiber-optical sensor for quality inspection of high-precision parts, such as injection nozzles, for common-rail diesel engines.     

Bistable Retinal Schiff Base Photodynamics of Histidine Kinase Rhodopsin HKR1 from Chlamydomonas reinhardtii

The photodynamics of the recombinant rhodopsin fragment of the histidine kinase rhodopsin HKR1 from Chlamydomonas reinhardtii was studied by absorption and fluorescence spectroscopy. The retinal cofactor of HKR1 exists in two Schiff base forms RetA and RetB. RetA is the deprotonated 13‐cis‐retinal Schiff base (RSB) absorbing in the UVA spectral region. RetB is the protonated all‐trans RSB absorbing in the blue spectral region. Blue light exposure converts RetB fully to RetA. UVA light exposure converts RetA to RetB and RetB to RetA giving a mixture determined by their absorption cross sections and their conversion efficiencies. The quantum efficiencies of conversion of RetA to RetB and RetB to RetA were determined to be 0.096 ± 0.005 and 0.405 ± 0.01 respectively. In the dark thermal equilibration between RetA and RetB with dominant RetA content occurred with a time constant of about 3 days at room temperature. The fluorescence emission behavior of RetA and RetB was studied, and fluorescence quantum yields of ?_F(RetA) = 0.00117 and ?_F(RetB) = 9.4 × 10^?5 were determined. Reaction coordinate schemes of the photodynamics are developed.     

Some tests for the helicity structure of the Pomeron in ep collisions

We discuss the reaction ep→epp?X in the onephoton exchange approximation, where it is in essence the reaction γ*p→p?X. A large rapidity gap is required between the particle or particles of the proton remnant pJ and those of X. We define a suitable azimuthal angle between a leptonic and a hadronic plane. The dependence of the cross section on is given explicitly and can be used to extract cross sections and interference terms for the reactionγ*p→p?X corresponding to the various helicities of the virtual photon γ*. The interference terms can be used to test models for the large rapidity gap events in a sensitive way. We discuss in detail models with factorizing Pomeron exchange and in particular the Donnachie- Landshoff Pomeron model. We make some remarks on soft colour exchange models and on possible effects of QCD background vacuum fields. We conclude with a suggestion to look for Odderon exchange in exclusive deep inelastic high energy reactions like γ*p→,p?π⁰and ?p→p?η.     

Are women better mindreaders? Sex differences in neural correlates of mentalizing detected with functional MRI

Background  

The ability to mentalize, i.e. develop a Theory of Mind (ToM), enables us to anticipate and build a model of the thoughts, emotions and intentions of others. It has long been hypothesised that women differ from men in their mentalizing abilities. In the present fMRI study we examined the impact of (1) gender (women vs. men) and (2) game partner (human vs. computer) on ToM associated neural activity in the medial prefrontal cortex. Groups of men (n = 12) and women (n = 12) interacted in an iterated classical prisoner's dilemma forced choice situation with alleged human and computer partners who were outside the scanner.     

A Critical Assessment of Particle Temperature Distributions During Plasma Spraying: Numerical Studies for YSZ

A three-dimensional computational model is used to simulate the in-flight particle melting behavior during plasma spraying process. The stochastic model is used for the particle size distribution. The particles surface temperature distributions at various spray distances have been presented. The results show that the surface temperature distribution varies with the spray distance. Single peak to double peaks and back to single peak has been observed in the simulations and also in the experiment. The effects of particle size and its distribution and plasma composition on the pattern shift have been investigated. Understanding the pattern shift may enable the design of a good control indicator to determine the particle melting status.     

The dynamical differential forms of the Klein—Gordon field

We classify the conserved currents for the Klein-Gordon field. We show that there are many which are not associated with invariances of the Lagrangian.     

Translation,dilatation, Lorentz invariant two-particle interactions

The existence of an infinite number of symmetric two-particle interactions is shown. These interactions are translation invariant, Lorentz invariant, and lead to second-order differential equations. Examples are analytic.