Browse Articles

Catalyst-free, microdroplet-mediated waste plastic conversion to diacids

Abstract Plastic waste accumulation poses a global threat to both the environment and public health 1–3 . Although catalytic upcycling to value-added chemicals holds promise, its industrial adoption is hindered by additive-induced catalyst deactivation, feedstock heterogeneity, process inflexibility and limited economic viability 4 . Here we report a catalyst-free upcycling strategy that makes use of in situ generation of hydroxyl radicals at microdroplet interfaces 5–8 to enable oxidative cleavage of diverse waste plastics—from polyolefins to rubbers—into carboxylic acids under mild conditions. By eliminating catalyst-dependent pathways, this approach circumvents key challenges of catalyst design and poisoning, while substantially lowering technical barriers and costs 9,10 . Our method achieves complete conversion of polyethylene (PE) with selectivity to short-chain diacids approaching 69% under relatively mild conditions and demonstrated broad applicability to mixed commercial plastics, with scalability demonstrated up to the 300-g scale. Radical intermediate analysis reveals the crucial role of H 2 O in mediating a unique oxidative degradation mechanism: sequential hydroxyl radical addition to alkyl radicals, distinct from classical liquid-phase aerobic oxidation of alkane 11 . This interfacial radical-mediated strategy enables sustainable polymer upcycling with minimal infrastructure. More broadly, this work provides a scalable blueprint for the first, to our knowledge, industrial implementation of microdroplet chemistry, with transformative implications for oxidation processes in organic acid synthesis and beyond.

Scalable quasi-pure MOF membranes for energy-efficient gas separations

Quantum statistical plasmonic metacrystals

How naked mole rat queens stop rivals reproducing

How to end poverty and protect Earth: inside the debate tearing up economics

Optical filter sorts light by its ‘quantum statistics’

Isotopic evidence for a cold and distant origin of 3I/ATLAS

Fractional high-Chern insulator in twisted rhombohedral graphene

Magnetic character of the low-energy enhancement in 70Zn

Biologists pinpoint how common virus triggers multiple sclerosis

Highly fragmented European wetlands with uneven restoration needs

Mathematics formula found on Maya wall rivals insights of ancient masters

‘Dark comet’ unmasked by its mysterious motions

RNA molecules with different destinies are processed through overlapping pathways

Party pooper: grandparents’ COVID risk rose after grandchildren’s birthdays

First ‘true sugar’ molecule found in space — offering hints to life’s origins

Lab-grown sperm: scientists inch closer to fertility breakthrough

Which ‘AI scientist’ suits your lab? A guide for the perplexed

Molecular basis of polyadenylated RNA fate determination in the nucleus

Abstract Eukaryotic genomes generate a plethora of polyadenylated (pA + ) RNAs 1,2 , which are packaged into ribonucleoprotein particles (RNPs). To ensure faithful gene expression, functional pA + RNPs, including protein-coding RNPs, are exported to the cytoplasm, whereas transcripts within non-functional pA + RNPs are degraded in the nucleus 1–4 . How cells distinguish these opposing fates remains unknown. The DExD-box ATPase UAP56 (also known as DDX39B) is a central component of functional pA + RNPs, and promotes their docking to the nuclear pore complex-anchored TREX-2 5,6 , which triggers transcript release from UAP56 to facilitate export 7 . Here we reveal that the poly(A) tail exosome targeting (PAXT) connection 8 binds a TREX-2-like module, which releases pA + RNAs from UAP56 for decay by the nuclear exosome. The core of this module consists of a LENG8–PCID2–SEM1 trimer, which we show is structurally and biochemically equivalent to the central GANP–PCID2–SEM1 trimer of TREX-2. Mutagenesis and transcriptomic data demonstrate that the nuclear fate of pA + RNPs is governed by the contending actions of nucleoplasmic PAXT and nuclear pore complex-associated TREX-2, which interpret RNA-bound UAP56 as a signal for RNA decay or export, respectively. As RNA targets of PAXT are generally short and intron-poor, we propose an overall model for pA + RNP fate determination whereby the distinct sub-nuclear localizations of PAXT and TREX-2 govern the degradation of short non-functional pA + RNAs while allowing export of their longer and functional counterparts.

A blastoporal organizer in a ctenophore

Abstract In an iconic experiment in 1924, Hilde Mangold and Hans Spemann established that the dorsal blastopore lip of amphibian embryos functions as an organizer and induces a secondary body axis when transplanted into a host embryo 1 . This discovery demonstrated that specific embryonic regions can regulate embryonic patterning and lead to the establishment of an entire body axis. Subsequent studies have revealed that cnidarians, the sister group to Bilateria, also possess a blastoporal embryonic organizer 2,3 . However, the evolutionary origin of the organizer remains unclear. Here we report that the blastopore lip of the ctenophore Mnemiopsis leidyi , a member of the evolutionary sister group to all other metazoans 4,5 , exhibits organizer activity. We show that transplanted fragments of blastopore lip tissue from M. leidyi gastrula induce secondary pharynx and mouth formation. Moreover, transphyletic transplantation experiments show that the blastopore lip of M. leidyi leads to the generation of a secondary body axis in embryos of the cnidarian Nematostella vectensis . Organizer function in M. leidyi requires both β-catenin and TGFβ signalling, and the TGFβ-family ligands probably provide this inductive capacity. These findings reveal the deep homology of the blastoporal organizer in ctenophores, cnidarians and vertebrates, implying the ancestral organizer role of the blastopore lip. We propose that the emergence of the organizer was an essential innovation that facilitated the change from the temporal cell differentiation of unicellular relatives to the spatial cell differentiation of the first multicellular embryo.