Confocal microscopy was used to directly observe the structural coarsening of the first layer of short colloidal rods sedimented onto a flat wall. Based on an image analysis algorithm we devised, quantitative information on the location, orientation and length of each particle can be extracted with high precision. At high density the system undergoes structural arrest, and becomes trapped in a disordered state of randomly arranged filaments that are composed of side-by-side aligned rods. The frustration of structural order is signalled by a new peak that emerges in the radial distribution function. Configuration analysis shows that the peak is primarily due to pairs of particles that are arranged in a "T" shape, a configuration that is compatible with neither crystallization nor filament growth. Our results point to a self-poisoning mechanism for the frustration of structural order, and highlight the importance of particle shape in controlling colloidal assembly thus materials properties.
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http://dx.doi.org/10.1039/c7sm01761h | DOI Listing |
PLoS Biol
January 2025
Institute for Biological Physics, University of Cologne, Cologne, Germany.
Type 4 pili (T4P) are multifunctional filaments involved in adhesion, surface motility, biofilm formation, and horizontal gene transfer. These extracellular polymers are surface-exposed and, therefore, act as antigens. The human pathogen Neisseria gonorrhoeae uses pilin antigenic variation to escape immune surveillance, yet it is unclear how antigenic variation impacts most other functions of T4P.
View Article and Find Full Text PDFPlant Cell Rep
January 2025
Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, China.
A high-throughput sequencing identified 1283 lncRNAs in anthers at different stages in Arabidopsis and their relationship with protein-coding genes and miRNAs during anther and pollen development were analyzed. Long non-coding RNAs (lncRNAs) are important regulatory molecules involved in various biological processes. However, their roles in male reproductive development and interactions with miRNAs remained elusive.
View Article and Find Full Text PDFNano Lett
January 2025
Wuhan National Laboratory for Optoelectronics, School of Integrated Circuits, Huazhong University of Science and Technology, Wuhan 430074, China.
Recent developments in artificial intelligence and the internet-of-things have created great demand for low-power microelectronic devices. Two-dimensional (2D) electrical switching materials are extensively used in neuromorphic computing technology, yet their high leakage current and low endurance impede their further application. This study presents a vertical crossbar-structured conductive-bridge threshold switching device based on 2D TaSe oxide.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
February 2025
Department of Biosphere Sciences and Engineering, Carnegie Institution for Science, Stanford, CA 94305.
Microbial mats are stratified communities often dominated by unicellular and filamentous phototrophs within an exopolymer matrix. It is challenging to quantify the dynamic responses of community members in situ as they experience steep gradients and rapid fluctuations of light. To address this, we developed a binary consortium using two representative isolates from hot spring mats: the unicellular oxygenic phototrophic cyanobacterium OS-B' (Syn OS-B') and the filamentous anoxygenic phototroph MS-CIW-1 (Chfl MS-1).
View Article and Find Full Text PDFBiophys J
January 2025
Department of Physics, Kansas State University, Manhattan, KS 66506, USA. Electronic address:
We present a model to describe the concentration-dependent growth of protein filaments. Our model contains two states, a low entropy/high affinity ordered state and a high entropy/low affinity disordered state. Consistent with experiments, our model shows a diffusion-limited linear growth regime at low concentration, followed by a concentration-independent plateau at intermediate concentrations, and rapid disordered precipitation at the highest concentrations.
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