No abstract

The detailed evolution of the magnitude of the local Jahn-Teller (JT) distortion in La1−xCaxMnO3 is obtained across the phase diagram for 0 ≤ x ≤ 0.5 from high quality neutron diffraction data using the atomic pair distribution function (PDF) method. A local JT distortion is observed in the insulating phase for all Ca concentrations studied. However, in contrast with earlier local structure studies its magnitude is not constant, but decreases continuously with increasing Ca content. This observation is at odds with a simple small-polaron picture for the insulating state.

workers present 3D biomimetic microvascular networks of nearly arbitrary design. The networks are fabricated using omnidirectional printing of a fugitive ink within a photopolymerizable hydrogel matrix. After printing and curing, the ink is removed from the matrix leaving behind hierarchical, bifurcating channels that mimic natural microvasculature. (Image credit:

No abstract

This work describes a non-enzymatic, isothermal genotyping method based on the kinetic differences exhibited in the dehybridization of perfectly matched (PM) and single-base mismatched (MM) DNA duplexes in an alkaline solution. Multifunctional encoded hydrogel particles incorporating allele-specific oligonucleotide (ASO) probes in two distinct regions were fabricated using microfluidic-based stop-flow lithography. Each particle contained two distinct ASO probe sequences differing at a single base position, and thus each particle was capable of simultaneously probing two distinct target alleles. Fluorescently labeled target alleles were annealed to both probe regions of a particle, and the rate of duplex dehybridization was observed using fluorescence microscopy. Duplex dehybridization was achieved through an alkaline stimulus using either a pH step function or a temporal pH gradient. When a single target probe sequence was used, the rate of mismatch duplex dehybridization could be discriminated from the rate of perfect match duplex dehybridization. In a more demanding application in which two distinct probe sequences were used, we found that the rate profiles provided a means to discriminate probe dehybridizations from both of the two mismatched duplexes as well as to distinguish at high certainty the dehybridization of the two perfectly matched duplexes. These results demonstrate an ability of alkaline dehybridization to correctly discriminate the rank hierarchy of thermodynamic stability among four sets of perfect match and single-base mismatch duplexes. We further demonstrate that these rate profiles are strongly temperature dependent and illustrate how the sensitivity can be compensated beneficially via the use of an actuating gradient pH field.