Volume 547 Number 7661

Editorials

Helium should be recycled p.6

The geopolitical crisis in the Middle East highlights the vulnerability of supplies of an essential research resource.

doi: 10.1038/547006a

News

News Features

Single-cell biology p.19

Analyses of life's most basic elements promise to improve therapies and provide insights into some of the most fundamental processes in biology.

doi: 10.1038/547019a

News & Views

Continuous chromatin changes p.34

DNA is packaged in the cell as chromatin, which folds into organized domains. Mapping of chromatin contacts in single cells sheds light on the dynamic evolution of these domains between cell divisions. See Article p.61

doi: 10.1038/547034a

Ice-sheet history revealed by fossils p.35

Microscopic fossils show that, from 10,400 to 7,500 years ago, upwelling of a water mass called Circumpolar Deep Water destabilized Antarctic ice shelves — a finding that advances our understanding of ice-sheet retreat. See Article p.43

doi: 10.1038/547035a

The patterns of T-cell target recognition p.36

The binding of T-cell receptors to peptide molecules not normally present in the body can trigger an immune response. Predicting which peptide a T-cell receptor will bind to — a difficult feat — has now been achieved. See Letters p.89 & p.94

doi: 10.1038/nature23091

3D integration advances computing p.38

Integrated circuits usually have only one layer of electronic devices, which limits their performance and functionality. A 3D integrated circuit that incorporates multiple device layers enables a wealth of applications. See Letter p.74

doi: 10.1038/547038a

Less is more in the hunt for driver mutations p.40

An analysis of 360 breast-cancer genomes has identified cancer-driving mutations in 9 non-coding DNA sequences called promoters, which regulate gene expression. The result hints at the prevalence of non-coding drivers. See Article p.55

doi: 10.1038/nature23085

Stellar siblings grow closer with age p.41

High-mass stars often pair up to form binary systems. Observations reveal that the stars in such systems are born farther apart than was formerly thought, casting fresh light on an enduring debate about star formation.

doi: 10.1038/nature23092

Articles

Climate change drives expansion of Antarctic ice-free habitat p.49

Permanently ice-free areas, home to almost all of Antarctica’s biodiversity, are projected, in the worst case, to expand by over 17,000 km2 as a result of climate change by the end of this century, with potentially deleterious consequences for the continent’s biodiversity.

doi: 10.1038/nature22996

Letters

Selective sp3 C–H alkylation via polarity-match-based cross-coupling p.79

The functionalization of carbon–hydrogen (C–H) bonds is one of the most attractive strategies for molecular construction in organic chemistry. The hydrogen atom is considered to be an ideal coupling handle, owing to its relative abundance in organic molecules and its availability for functionalization at almost any stage in a synthetic sequence. Although many C–H functionalization reactions involve C(sp3)–C(sp2) coupling, there is a growing demand for C–H alkylation reactions, wherein sp3 C–H bonds are replaced with sp3 C–alkyl groups. Here we describe a polarity-match-based selective sp3 C–H alkylation via the combination of photoredox, nickel and hydrogen-atom transfer catalysis. This methodology simultaneously uses three catalytic cycles to achieve hydridic C–H bond abstraction (enabled by polarity matching), alkyl halide oxidative addition, and reductive elimination to enable alkyl–alkyl fragment coupling. The sp3 C–H alkylation is highly selective for the α-C–H of amines, ethers and sulphides, which are commonly found in pharmaceutically relevant architectures. This cross-coupling protocol should enable broad synthetic applications in de novo synthesis and late-stage functionalization chemistry.

doi: 10.1038/nature22813

Identifying specificity groups in the T cell receptor repertoire p.94

The authors devise an algorithm that can cluster T cell receptor (TCR) sequences sharing the same specificity, predict the HLA restriction of these TCR clusters on the basis of subjects’ genotypes and help to identify specific peptide major histocompatibility complex ligands.

doi: 10.1038/nature22976