Swept-source optical coherence tomography (SS-OCT) is a non-invasive imaging method using a frequency-swept laser to produce detailed cross-sectional images. It offers enhanced imaging speed, improved sensitivity, and a wider scanning range but faces an imaging ambiguity known as the complex conjugate artifact (CCA). To overcome CCA, 3×3 coupler systems are used but require trigonometric conversions. This study presents an SS-OCT system with a 4×4 coupler and dual reference arms, enabling direct quadrature detection and balanced photodetection, thereby doubling the imaging depth and sensitivity. Additionally, the dual reference arms that modulate the optical path difference extend the depth range twofold. Combining both the 4×4 coupler and dual reference arms, the proposed system achieves a fourfold increase in the depth range compared to conventional SS-OCT systems.

Brown algae (Phaeophyceae) play vital ecological roles in marine ecosystems and are important models for studying organelle genome evolution. Despite their significance, mitogenome data for many taxa remain limited. In this study, we present the complete mitogenome sequence of <i>Dictyota coriacea</i>, a representative brown alga from the family Dictyotaceae (Phaeophyceae). The circular mitogenome of <i>D. coriacea</i> is 31,573 bp in length and encodes 62 genes, including 35 protein-coding genes (PCGs; including uncharacterized open reading frame (<i>orf109</i>)), 25 tRNAs, and 3 rRNAs. The overall gene content and arrangement are largely conserved and consistent with other Dictyotaceae species. However, minor but notable genomic variations were observed, such as gene overlaps, variation in gene lengths, and differences in tRNA gene copy numbers, and the absence of <i>rpl31</i>. All PCGs use standard start and stop codons, with most initiating with ATG and terminating with TAA, TAG, or TGA. Phylogenetic analysis confirmed <i>D. coriacea's</i> close relationship with <i>D. dichotoma</i>, <i>Dictyopteris divaricata</i>, and <i>Dictyotopsis propagulifera</i>, supporting its taxonomic placement. This study's findings improve our understanding of algae evolution and provide useful genetic markers for future research on evolutionary relationships and species classification within this group of algae.

Flocculation represents a promising biological strategy to enhance biomass recovery and improve process efficiency in bioethanol production. In this study, we engineered a self-flocculating strain of Zymomonas mobilis, designated ZAM2, by inactivating the EAL domain (phosphodiesterase region) of the regulatory gene ZMO_1055. This targeted genetic modification led to enhanced cell aggregation and improved stress tolerance against common fermentation inhibitors, including acetic acid, furfural, and vanillin, which are typically generated during lignocellulosic biomass pretreatment. Compared to its parental strain ZM401, ZAM2 accumulated higher levels of intracellular c-di-GMP, exhibited reduced PDE activity, and upregulated cellulose biosynthesis genes. These changes contributed to enlarged floc size and superior fermentation performance. Notably, ZAM2 completed glucose consumption and ethanol production more rapidly than ZM401 under inhibitor-rich conditions, resulting in increased ethanol productivity. Our results demonstrate a rational genetic strategy for enhancing microbial robustness and process efficiency, offering a viable approach for sustainable, high-gravity bioethanol fermentation from lignocellulosic feedstocks.