Orientational Order of Linkers Controls ZIF-8 Crystallization.

September 9, 2026| Source: Journal of the American Chemical Society

Zeolitic imidazolate framework-8 (ZIF-8) crystallizes through an amorphous intermediate, but the molecular events that trigger nucleation within this disordered phase have remained elusive. Here we introduce a dynamic-binding, implicit-solvent force field for the ionic building units of ZIF-8 that enables unbiased microsecond-scale molecular dynamics of the full crystallization pathway─from solvated monomers to a 10 nm ZIF-8 nanocrystal. Our simulations reproduce the experimentally observed multistep pathway: monomers and oligomers phase-separate into a solute-rich amorphous network with liquid-like dynamics, lower density, and predominantly three-coordinated Zn. Whereas crystalline ZIF-8 is defined by sterically constrained, near-tetrahedral Zn(mIm)4 nodes, the amorphous network sustains a broad distribution of coordination environments and linker orientations. Nucleation occurs within this disordered phase through collective rearrangements that anneal misconfigured Zn(mIm)4 nodes and couple linker rotational fluctuations to topological reorganization, locking in the four-connected framework. Crystal growth proceeds by the same defect-annealing mechanism. These results identify linker configurational dynamics as key for ZIF-8 nucleation, and provide a molecular foundation for understanding multistep MOF crystallization.

Read the original source →

Widespread plasma jets in the Martian magnetosheath revealed by dual-spacecraft observations.

Plasma jets in planetary magnetosheaths are transient, high dynamic pressure structures capable of strongly perturbing downstream magnetospheres and modulating solar wind energy transfer. Although recently identified at Mars, their formation mechanisms and global occurrence remain poorly constrained. Using dual-spacecraft observations from Mars Atmosphere and Volatile EvolutioN and Tianwen-1, we show that magnetosheath jets occur throughout the Martian magnetosheath, in striking contrast to Eart

EnvironmentNovember 3, 2026

Defining and measuring proximity to criticality based on univariate time series.

Diverse social, engineered, and biological systems are made up of multiple interacting dynamical components; to work properly, certain components must be carefully regulated so that their dynamics avoid instability. However, many desirable properties, like optimized computation and control, emerge close to the tipping point between stability and instability, i.e., near criticality. Claims that such dynamical systems operate near criticality have been controversial because it is difficult to asse

EnvironmentNovember 3, 2026

Orexin and pupillary modulation for hunger control.

Fasting-based interventions improve metabolic health and are also explored as adjuncts in other clinical settings, but hunger remains a barrier to adherence. Fasting activates AgRP/NPY neurons (ANs), a hunger-promoting population whose inhibition reduces eating in hungry animals. Here we identify hypocretin/orexin neurons (HONs), classically associated with arousal, as rapid suppressors of AN activity. HON ablation increased AN population activity, whereas HON optostimulation rapidly suppressed

EnvironmentNovember 3, 2026

Environmental RNA improves detection and surveillance of schistosomiasis transmission.

Environmental diagnosis of schistosomiasis, a disease affecting over 250 million people globally, remains challenging, thereby limiting efficient eradication efforts. Current methods, including environmental DNA (eDNA), cannot distinguish between infectious parasite life stages present in the environment. Here, we develop and validate an environmental RNA (eRNA) approach that enables detection and quantification of Schistosoma mansoni miracidia (infective to snails) and cercariae (infective to h

EnvironmentOctober 29, 2026

Gram-Negative Bacterial Resistance.

The rapid worldwide spread of antimicrobial resistance among gram-negative bacteria is driven by a complex interplay of human, environmental, and health care-associated factors and accelerated by mobile genetic elements that facilitate the dissemination of resistance genes. Resistance in gram-negative bacteria arises primarily through reduced drug entry, active drug efflux, modification of antibiotic targets, and enzymatic drug inactivation, most notably through β-lactamase production. Cli