Cellular communities in living tissues act in concert to establish intricate microenvironments, with complexity difficult to recapitulate in vitro. We report a method for docking numerous cellularized hydrogel shapes (100–1,000 µm in size) into hydrogel templates to construct 3D cellular microenvironments. Each shape can be uniquely designed to contain customizable...

Redox transitions of uranium [from U(VI) to U(IV)] in low-temperature sediments govern the mobility of uranium in the environment and the accumulation of uranium in ore bodies, and inform our understanding of Earth’s geochemical history. The molecular-scale mechanistic pathways of these transitions determine the U(IV) products formed, thus influencing uranium...

A classical theorem of MacMahon states that the number of lozenge tilings of any centrally symmetric hexagon drawn on the triangular lattice is given by a beautifully simple product formula. In this paper, we present a counterpart of this formula, corresponding to the exterior of a concave hexagon obtained by...

The group of piecewise projective homeomorphisms of the line provides straightforward torsion-free counterexamples to the so-called von Neumann conjecture. The examples are so simple that many additional properties can be established.

Cell-free gene expression in localized DNA brushes on a biochip has been shown to depend on gene density and orientation, suggesting that brushes form compartments with partitioned conditions. At high density, the interplay of DNA entropic elasticity, electrostatics, and excluded volume interactions leads to collective conformations that affect the function...

Dynamical information on spin degrees of freedom of proteins or solids can be obtained by NMR and electron spin resonance. A technique with similar versatility for charge degrees of freedom and their ultrafast correlations could move the understanding of systems like unconventional superconductors forward. By perturbing the superconducting state in...

Several aid groups have proposed strategies for allocating ready-to-use (therapeutic and supplementary) foods to children in developing countries. Analysis is needed to investigate whether there are better alternatives. We use a longitudinal dataset of 5,657 children from Bwamanda to construct a bivariate time-series model that tracks each child’s height-for-age z...

Parsing a brain region’s disparate rolespnas;110/12/4431/UNFIG01F1unfig01Hippocampus and rodent path integration.The hippocampus and related structures in the brain’s medial temporal lobe (MTL) are thought to mediate both long-term memory and spatial cognition, but the link between these seemingly disparate functions remains unclear. Soyun Kim et al. (pp. 4732–4737) explored the effects...

On March 3, 2013 the National Academy of Sciences will be 150 years old. Its creation in 1863 represents part of a dramatic series of federal actions that positioned the United States of America for a bright future. In 1862, Congress passed and President Lincoln signed the Morrill Act, creating...

As a young resident doctor at France’s Hôpitaux de Paris in the 1970s, Philippe Sansonetti saw a lot of patients with infectious diseases, such as typhoid, whooping cough, and leprosy. Sansonetti and his colleagues treated those patients with antibiotics. By that point, however, the first signs of antibiotic resistance were...

A long-standing mystery has been understanding why neurons die in devastating neurodegenerative disorders, such as Alzheimer’s disease, Parkinson disease, and amyotrophic lateral sclerosis (ALS). Abnormal intracellular protein aggregates are a hallmark feature of many neurodegenerative conditions. Based on this fundamental observation, numerous studies have attempted to shed light on the...

Over the past 50 y, there have been few mechanistically distinct drugs for the treatment of major depressive disorders, despite the fact that nearly two-thirds of patients do not achieve full remission of symptoms on currently available antidepressants (1). In addition, even when adequate remission is achieved, patients require 2–4...

Gibberellins (GA) represent a key class of hormone signals that promote plant growth and development (1). A key part of the Green Revolution, which saw crop yields more than double, was the development of new dwarf varieties, many of which were later found to have mutations in the GA pathway...

Nitrous oxide (N2O) is the largest known remaining anthropogenic threat to the stratospheric ozone layer. However, it is currently only regulated under the 1997 Kyoto Protocol because of its simultaneous ability to warm the climate. The threat N2O poses to the stratospheric ozone layer, coupled with the uncertain future of...

Efficient computation of geophysical turbulence, such as occurs in the atmosphere and ocean, is a formidable challenge for the following reasons: the complex combination of waves, jets, and vortices; significant energetic backscatter from unresolved small scales to resolved large scales; a lack of dynamical scale separation between large and small...

The Gram-negative enteroinvasive bacterium Shigella flexneri is responsible for the endemic form of bacillary dysentery, an acute rectocolitis in humans. S. flexneri uses a type III secretion system to inject effector proteins into host cells, thus diverting cellular functions to its own benefit. Protective immunity to reinfection requires several rounds...

Predicting climate change is a high priority for society, but such forecasts are notoriously uncertain. Why? Even should climate prove theoretically predictable—by no means certain—the near-absence of adequate observations will preclude its understanding, and hence even the hope of useful predictions. Geological and cryospheric records of climate change and our...

When you’re standing in the middle of Stony Brook University’s Reality Deck looking at a world map, you can see the organization of the continents that surround you—literally. Covering the four walls—and even the door—of the cave-like room are 416 27-inch screens containing a total of 1.5 billion pixels. If...

Autotransporters are bacterial virulence factors that contain an N-terminal extracellular (“passenger”) domain and a C-terminal β barrel (“β”) domain that anchors the protein to the outer membrane. The β domain is required for passenger domain secretion, but its exact role in autotransporter biogenesis is unclear. Here we describe insights into...

Long-term depression (LTD) commonly affects learning and memory in various brain regions. Although cerebellar LTD absolutely requires the δ2 glutamate receptor (GluD2) that is expressed in Purkinje cells, LTD in other brain regions does not; why and how cerebellar LTD is regulated by GluD2 remains unelucidated. Here, we show that...