Articles

Recent technological advances have allowed the expansion of spermatogonial stem cellsin vitro; however, in vivo conditions are required for the full differentiation of the cells. In this study, an in vitroorgan culture system is developed that allows the differentiation of the germ cells in the laboratory.

Hydrogels have a variety of applications including tissue engineering and controlled drug delivery. Here, liquid-crystal hydrogels are developed which transform into a fluid solution upon cooling; cells can be encapsulated in the gel at room temperature, then released at physiological temperatures.

Quadrupoles have many engineering applications, but experimental observations of fluidic multipoles have not been reported. This study presents an experimental two-dimensional microfluidic quadrupole, a theoretical analysis consistent with observations, and a first application as a channel-free floating gradient generator.

Transforming growth factor-β blocks the activation of pro-inflammatory cytokines, in part by the degradation of Myd88. This study shows that smad ubiquitin regulator proteins are shown to mediate the destruction of Myd8 and are therefore required for the anti-inflammatory effects of transforming growth factor-β.

In response to antigens, B cells proliferate and form germinal centres before differentiating into memory B cells or long-lived plasma cells. Here, a culture method is used to expand B cells in vitro, with the ability to shift the fate of the cells between memory B cells and long-lived plasma cells.

Property coupling by heteroepitaxy is severely limited in material combinations with highly dissimilar bonding. This report presents a chemical boundary condition methodology to actively engineer two-dimensional film growth in such systems that otherwise collapse into island formation and rough morphologies.

The measurement of the total cross-section of proton–proton collisions is of fundamental importance for particle physics. Here, the first measurement of the inelastic cross-section is presented for proton–proton collisions at an energy of 7 teraelectronvolts using the ATLAS detector at the Large Hadron Collider.

Group BStreptococcuscauses meningitis in newborn infants but how the bacterium crosses the blood-brain barrier is unknown. Here, the bacterial pili adhesion molecule, PilA, is shown to bind to collagen and promote binding of the bacteria to integrins expressed on the blood-brain endothelium.

The appearance of a new intron that splits an exon without disrupting the corresponding peptide sequence is a rare event in vertebrate genomes. Hellstenet al.demonstrate that, under certain circumstances, a functional intron can be produced in a single step by segmental genomic duplication.

Cell-penetrating peptides can deliver molecular cargoes into living cells, and cross biological membranes by transduction—a non-endocytic mechanism. Here, the transduction efficiency of cyclic arginine-rich peptides is shown to be higher than that of more flexible linear peptides.

Autostereoscopic three-dimensional displays allow the perception of depth, by presenting offset images to the left and right eye, without the need for specialized glasses. Yoonet al propose a Luciusmicroprism array to control the directionality and intensity of light in three-dimensional displays.

Photodetection is believed to be among the most promising potential applications for graphene. Here, by combining graphene with plasmonic nanostructures, the efficiency of graphene-based photodetectors is increased by up to two orders of magnitude.

Many mammals are born with an immature intestinal epithelium, which adapts to a changing diet during the weaning period. Muncanet al. show that the transcriptional repressor Blimp1is expressed in the intestine of mice at birth, and that expression is lost at the transition to the weaning stage.

Various methods have been investigated to locally control atmospheric precipitation. In this study, field experiments show that laser-induced condensation is initiated when the relative humidity exceeds 70%, and that this effect is largely a result of photochemical HNO₃formation.

The assembly mechanisms of heteromeric ion channels are poorly understood. Using a range of techniques, Shuartet al.determine the mechanism by which rod photoreceptor cyclic nucleotide-gated channels assume a 3:1 stoichiometry of CNGA1 and CNGB1 subunits.

The origin of Cnidaria—coral and jellyfish—is still unsolved in the basal metazoan phylogeny. Here, a Cambrian fossil of a stem-group cnidarian,Cambroctoconus orientalisgen. et sp. nov., is found to bear octoradial symmetry, but no jelly-like mesenchyme, suggesting this evolved after octoradial symmetry.

Determining the direction of the magnetic field of light is important for optical applications. Here, scattering of light from a subwavelength aperture in a metal plane is shown to be governed by its magnetic vector, providing the magnetic field orientation independently of the electric field.

Multiple scattering complicates femtosecond optics such that phase conjugation allows spatial focusing and imaging through a multiple scattering medium, but temporal control is problematic. McCabeet al. report the full spatio-temporal characterization and recompression of a femtosecond speckle field.

The development of radial progenitor cells and astroglia in the cerebral cortex depends on the microtubule cytoskeleton. Eomet al. have developed a new mouse model where the microtubules of astrocytes and radial glia cells are fluorescently tagged, facilitating the detailed study of microtubule dynamics and development in these cells.

Harvestmen — Opiliones — are an ancient and diverse arachnid group with a limited fossil record. Here, X-ray micro-tomography of fossils reveals two new Carboniferous harvestmen species, allowing a phylogenetic analysis of these Palaeozoic Opiliones, demonstrating similarities between the fossils and extant groups.