We introduce ultraresolving terahertz (THz) near-field microscopy based on THz scattering at atomic force microscope tips. Nanoscale resolution is achieved by THz field confinement at the very tip apex to within 30 nm, which is in good agreement with full electro-dynamic calculations. Imaging semiconductor transistors, we provide first evidence of 40 nm (lambda/3000) spatial resolution at 2.54 THz (wavelength lambda=118 microm) and demonstrate the simultaneous THz recognition of materials and mobile carriers in a single nanodevice. Fundamentally important, we find that the mobile carrier contrast can be directly related to near-field excitation of THz-plasmons in the doped semiconductor regions. This opens the door to quantitative studies of local carrier concentration and mobility at the nanometer scale. The THz near-field response is extraordinary sensitive, providing contrast from less than 100 mobile electrons in the probed volume. Future improvements could allow for THz characterization of even single electrons or biomolecules.
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http://dx.doi.org/10.1021/nl802086x | DOI Listing |
Biochemistry
January 2025
BHF Centre of Research Excellence, School of Medicine and Life Sciences, King's College London, London SE1 9NH, United Kingdom.
Transmembrane glucose transport, facilitated by glucose transporters (GLUTs), is commonly understood through the simple mobile carrier model (SMCM), which suggests that the central binding site alternates exposure between the inside and outside of the cell, facilitating glucose exchange. An alternative "multisite model" posits that glucose transport is a stochastic diffusion process between ligand-operated gates within the transporter's central channel. This study aims to test these models by conducting atomistic molecular dynamics simulations of multiple glucose molecules docked along the central cleft of GLUT1 at temperatures both above and below the lipid bilayer melting point.
View Article and Find Full Text PDFPolymers (Basel)
January 2025
School of Chemical Engineering, Yeungnam University, 280 Daehak-ro, Gyeongsan 38541, Republic of Korea.
Solid polymer electrolytes (SPEs) for symmetrical supercapacitors are proposed herein with activated carbon as electrodes and optimized solid polymer electrolyte membranes, which serve as the separators and electrolytes. We propose the design of a low-cost solid polymer electrolyte consisting of guanidinium nitrate (GuN) and poly(ethylene oxide) (PEO) with poly(vinylpyrrolidone) (PVP). Using the solution casting approach, blended polymer electrolytes with varying GuN weight percentage ratios of PVP and PEO are prepared.
View Article and Find Full Text PDFSensors (Basel)
January 2025
School of Business, Beijing Wuzi University, Beijing 101149, China.
Unmanned aerial vehicle (UAV)-based wireless sensor networks (WSNs) hold great promise for supporting ground-based sensors due to the mobility of UAVs and the ease of establishing line-of-sight links. UAV-based WSNs equipped with mobile edge computing (MEC) servers effectively mitigate challenges associated with long-distance transmission and the limited coverage of edge base stations (BSs), emerging as a powerful paradigm for both communication and computing services. Furthermore, incorporating simultaneously transmitting and reflecting reconfigurable intelligent surfaces (STAR-RISs) as passive relays significantly enhances the propagation environment and service quality of UAV-based WSNs.
View Article and Find Full Text PDFMicroorganisms
January 2025
College of Food Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China.
As the mobile cassette carrier of the methicillin resistance gene that is transported across staphylococci species, the evolution and origin of Staphylococcal Cassette Chromosome (SCC)-and in particular, the composition of and SCC-have been extensively discussed in the scientific literature; however, information regarding its dissemination across geographical limits and evolution over decades remains limited. In addition, whole-genome sequencing-based macro-analysis was unable to provide sufficiently detailed evolutionary information on SCC. Herein, the cassette chromosome recombinase genes , as essential components of SCC, were employed to explore the evolution of SCC.
View Article and Find Full Text PDFWater Res
January 2025
State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing, Jiangsu 210023, China. Electronic address:
To address the challenge of antibiotic-containing wastewater, a novel micromagnetic carrier-modified integrated fixed-film activated sludge system (MC-IFAS) was developed for treating tetracycline (TC)-containing swine wastewater in this study. The magnetic effects of the MC significantly enhanced TC removal by improving TC biosorption and biodegradation in both the suspended activated sludge and the carrier-attached biofilm in the MC-IFAS. The increased electrostatic attraction and number of binding sites in both the activated sludge and the biofilm enhanced their TC biosorption capacities, particularly in the activated sludge.
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