13 research outputs found
Organic Crystal Growth: Hierarchical Self-Assembly Involving Nonclassical and Classical Steps
Organic crystal nucleation and growth are complex processes
that
often do not fit into the framework of the existing crystallization
theories. We investigated a crystal growth mechanism of an organic
dye, perylene diimide, using high-resolution cryogenic transmission
electron microscopy and optical spectroscopy. The elucidated mechanism
involves classical (monomer attachments) and nonclassical pathways,
exhibiting a self-assembly sequence where all steps are interconnected.
It starts from the assembly of molecular π-stacks that are initially
disordered. They gradually optimize their structure, rigidify, and
interact to form crystalline domains. The latter further evolve via
the addition of individual molecules, and crystal fusion (via oriented
attachment). All the observed supramolecular transformations are connected
and follow a clear hierarchy starting from the molecular-scale interactions.
The elucidation of the complex pathway of organic crystallization
as a series of coordinated supramolecular transformations at multiple
scales conceptually advances the understanding of order evolution
in organic matter
Nationwide Outbreak of Candida auris Infections Driven by COVID-19 Hospitalizations, Israel, 2021–2022
We report an outbreak of Candida auris across multiple healthcare facilities in Israel. For the period of May 2014–May 2022, a total of 209 patients with C. auris infection or colonization were identified. The C. auris incidence rate increased 30-fold in 2021 (p = 0.00015), corresponding in time with surges of COVID-19–related hospitalization. Multilocus sequence typing revealed hospital-level outbreaks with distinct clones. A clade III clone, imported into Israel in 2016, accounted for 48.8% of typed isolates after January 2021 and was more frequently resistant to fluconazole (100% vs. 63%; p = 0.00017) and voriconazole (74% vs. 5.2%; p<0.0001) than were non–clade III isolates. A total of 23% of patients had COVID-19, and 78% received mechanical ventilation. At the hospital level, outbreaks initially involved mechanically ventilated patients in specialized COVID-19 units and then spread sequentially to ventilated non–COVID-19 patients and nonventilated patients