Volume 555 Issue 7697



News Features

When antibiotics turn toxic p.431

Commonly prescribed drugs called fluoroquinolones cause rare, disabling side effects. Researchers are struggling to work out why.

doi: 10.1038/d41586-018-03267-5

News & Views

Machine learning classifies cancer p.446

Brain tumours are often classified by visual assessment of tumour cells, yet such diagnoses can vary depending on the observer. Machine-learning methods to spot molecular patterns could improve cancer diagnosis.

doi: 10.1038/d41586-018-02881-7

A diamond age of masers p.447

Applications for masers — the microwave equivalent of lasers — have been hindered by their extreme operating conditions and the inability to produce continuous emissions. A diamond maser overcomes these limitations.

doi: 10.1038/d41586-018-03215-3

Protein aggregates caught stalling p.449

Low-complexity protein aggregates are a hallmark of neurodegeneration. High-resolution snapshots of the structure of one such aggregate offer an unprecedented view of how these proteins disrupt crucial cellular functions.

doi: 10.1038/d41586-018-03000-2

Calcium signals in planetary embryos p.451

The calcium-isotope composition of planetary bodies in the inner Solar System correlates with the masses of such objects. This finding could have implications for our understanding of how the Solar System formed.

doi: 10.1038/d41586-018-03144-1

A mixed model of neuronal diversity p.452

Two groups have sequenced RNA from thousands of single cells, making the deepest ventures yet into the origins of neuronal diversity in the neocortex of the developing mammalian brain.

doi: 10.1038/d41586-018-02539-4

A cellular passage to the root interior p.454

Water-conducting tissues inside plant roots are surrounded by impermeable cells. This protective barrier is punctured by ‘passage cells’, which are thought to regulate nutrient uptake. How these cells form has now been revealed.

doi: 10.1038/d41586-018-02861-x



Image reconstruction by domain-transform manifold learning p.487

Image reconstruction is reformulated using a data-driven, supervised machine learning framework that allows a mapping between sensor and image domains to emerge from even noisy and undersampled data, improving accuracy and reducing image artefacts.

doi: 10.1038/nature25988

Continuous-wave room-temperature diamond maser p.493

The maser—the microwave progenitor of the optical laser—has been confined to relative obscurity owing to its reliance on cryogenic refrigeration and high-vacuum systems. Despite this, it has found application in deep-space communications and radio astronomy owing to its unparalleled performance as a low-noise amplifier and oscillator. The recent demonstration of a room-temperature solidstate maser that utilizes polarized electron populations within the triplet states of photo-excited pentacene molecules in a p-terphenyl host1–3 paves the way for a new class of maser. However, p-terphenyl has poor thermal and mechanical properties, and the decay rates of the triplet sublevel of pentacene mean that only pulsed maser operation has been observed in this system. Alternative materials are therefore required to achieve continuous emission: inorganic materials that contain spin defects, such as diamond4–6 and silicon carbide7, have been proposed. Here we report a continuous-wave room-temperature maser oscillator using optically pumped nitrogen–vacancy defect centres in diamond. This demonstration highlights the potential of room-temperature solid-state masers for use in a new generation of microwave devices that could find application in medicine, security, sensing and quantum technologies.

doi: 10.1038/nature25970