We present waveguide Bragg gratings with misaligned sidewall corrugations on a silicon-on-insulator platform. The grating strength can be tuned by varying the misalignment between the corrugations on the two sidewalls. This approach allows for a wide range of grating coupling coefficients to be achieved with precise control, and substantially reduces the effects of quantization error due to the finite mask grid size. The experimental results are in very good agreement with simulations using the finite-difference time-domain (FDTD) method.
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http://dx.doi.org/10.1364/OL.39.005519 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Institute of Science and Technology Austria, AT-3400 Klosterneuburg, Austria.
Biophysical constraints limit the specificity with which transcription factors (TFs) can target regulatory DNA. While individual nontarget binding events may be low affinity, the sheer number of such interactions could present a challenge for gene regulation by degrading its precision or possibly leading to an erroneous induction state. Chromatin can prevent nontarget binding by rendering DNA physically inaccessible to TFs, at the cost of energy-consuming remodeling orchestrated by pioneer factors (PFs).
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong 10120, Thailand.
A single-component flavin-dependent halogenase, AetF, has emerged as an attractive biocatalyst for catalyzing halogenation. However, its flavin chemistry remains unexplored and cannot be predicted due to its uniqueness in sequence and structure compared to other flavin-dependent monooxygenases. Here, we investigated the flavin reactions of AetF using transient kinetics.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
National Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
To bolster the capacity for managing potential infectious diseases in the future, it is critical to develop specific antiviral drugs that can be rapidly designed and delivered precisely. Herein, a CRISPR/Cas13d system for broad-spectrum targeting of influenza A virus (IAV) from human, avian, and swine sources is designed, incorporating Cas13d mRNA and a tandem CRISPR RNA (crRNA) specific for the highly conserved regions of viral polymerase acidic (PA), nucleoprotein (NP), and matrix (M) gene segments, respectively. Given that the virus targets cells with specific receptors but is not limited to a single organ, a Susceptible Cell Selective Delivery (SCSD) system is developed by modifying a lipid nanoparticle with a peptide mimicking the function of the hemagglutinin of influenza virus to target sialic acid receptors.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2025
ETH Zurich, Department of Biosystems Science and Engineering, Klingelbergstrasse 48, Basel, CH-4056, Switzerland.
Neo-vascularization plays a key role in achieving long-term viability of engineered cells contained in medical implants used in precision medicine. Moreover, strategies to promote neo-vascularization around medical implants may also be useful to promote the healing of deep wounds. In this context, a biocompatible, electroconductive borophene-poly(ε-caprolactone) (PCL) 3D platform is developed, which is called VOLT, to support designer cells engineered with a direct-current (DC) voltage-controlled gene circuit that drives secretion of vascular endothelial growth factor A (VEGFA).
View Article and Find Full Text PDFSci Adv
January 2025
Department of Materials Science and Engineering, The University of Tennessee, Knoxville, TN 37996, USA.
Light, strong, and radiation-tolerant materials are essential for advanced nuclear systems and aerospace applications. However, the comprehensive properties of current radiation-tolerant materials are far from being satisfactory in harsh operating environments. In this study, a high-throughput-designed NbVTaSi refractory eutectic medium entropy alloy realizes the controllable formation of the β-NbSi phase with a high content and has outstanding comprehensive properties, i.
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