Transfer RNA (tRNA)-derived small RNAs (tsRNAs), a novel category of small noncoding RNAs, are enzymatically cleaved from tRNAs. Previous reports have shed some light on the roles of tsRNAs in the ...development of human diseases. However, our knowledge about tsRNAs is still relatively lacking. In this paper, we review the biogenesis, classification, subcellular localization as well as action mechanism of tsRNAs, and discuss the association between chemical modifications of tRNAs and the production and functions of tsRNAs. Furthermore, using immunity, metabolism, and malignancy as examples, we summarize the molecular mechanisms of tsRNAs in diseases and evaluate the potential of tsRNAs as new biomarkers and therapeutic targets. At the same time, we compile and introduce several resource databases that are currently publicly available for analyzing tsRNAs. Finally, we discuss the challenges associated with research in this field and future directions.
Oil/water separation (OWS) technology has become an increasingly crucial tool to protect the environment and reduce the economic losses caused by the discharge of oily wastewater and oil spills. ...Recently, porous materials with superwettability have been applied in effective OWS and have achieved tremendous success. Herein, we review recent advancements of OWS utilizing femtosecond (fs) laser-structured superhydrophobic or underwater superoleophobic porous materials. We will review the enabling materials processing and treatment methods, their surface wettability, the separating methods and processes, and the separation mechanisms. Inspired by lotus leaves and fish scales, superhydrophobic and underwater superoleophobic properties are artificially achieved on substrate surfaces by fs laser processing. By using fs laser-structured superwetting porous materials, various oil/water mixtures (OWMs) are successfully separated through different separation methods. Presently, the research of fs laser-based OWS is still in its infancy. We will also discuss the current challenges and future prospects in this emerging field. It is expected that the advanced features of fs laser microfabrication will lead to exciting applications for OWS.
Recent applications of the femtosecond laser-structured superhydrophobic or underwater superoleophobic porous materials in oil/water separation are summarized in this review.
Despite extensive studies of femtosecond laser-material interactions, even the simplest morphological responses following femtosecond pulse irradiation have not been fully resolved. Past studies have ...revealed only partial dynamics. Here we develop a zero-background and high-contrast scattered-light-based optical imaging technique through which we capture, for the first time, the complete temporal and spatial evolution of the femtosecond laser-induced morphological surface structural dynamics of metals from start to finish, that is, from the initial transient surface fluctuations, through melting and ablation, to the end of resolidification. We find that transient surface structures first appear at a delay time on the order of 100 ps, which is attributed to ablation driven by pressure relaxation in the surface layer. The formation dynamics of the surface structures at different length scales are individually resolved, and the sequence of their appearance changes with laser fluence is found. Cooling and complete resolidification, observed here for the first time, are shown to occur more slowly than previously predicted by two orders of magnitude. We examine and identify the mechanisms driving each of these dynamic steps. The visualization and control of morphological surface structural dynamics not only are of fundamental importance for understanding femtosecond laser-induced material responses but also pave the way for the design of new material functionalities through surface structuring.
Plasmonic nanoantennas have earned strong recognition for their unique capability to confine light from free space into sub-wavelength dimensions with strong electric field (E-field) enhancement ...factor due to localized surface plasmon resonance (LSPR). Broad spectral tuning of LSPR from ultraviolet (UV) to near-infrared (NIR) is required for incident light wavelength and material sensitive plasmonic applications in different spectral regions. In this article, we introduced and designed a novel aluminum plasmonic platform consisting of a bowtie nanoantenna (BNA) array with metal-insulator-metal (MIM) configuration where LSPR peak position was broadband tunable from UV to NIR through geometric control of antenna parameters. Furthermore, we designed and numerically analyzed a plasmonic biosensor platform that detected concentration of glycerol in de-ionized (DI) water with a concentration in the range of 0 to 40 wt% (refractive index = 1.333 to 1.368) with a sensitivity of 497 nm/RIU (refractive index units). The designed plasmonic platform can also be used as a surface-enhanced Raman scatting (SERS) substrate with enhancement factor as high as 4.82 × 10
9
for 1042 nm excitation wavelength. The reported hybrid dielectric-metallic plasmonic nanostructured system is a universal plasmonic platform for a wide range of applications including single-molecule SERS, biosensing, fluorescence microscopy, plasmonic nanocavity, nanolasers, and solid-state lighting.
Abstract
Unambiguous determination of the electric field of arbitrary ultrashort pulses is the key for time and frequency standards, attosecond science, and precision spectroscopy. However, a ...single-step technique that can simultaneously and directly characterize the spectrum, spectral phase, and the carrier-envelope phase (CEP) information of an arbitrary ultrashort pulse remains elusive. This technological roadblock hinders the current field from studying non-repeating single-shot events, since ultrashort laser pulses are often unstable. Here, we introduce a single-step reference-free technique through polarization interfering electric field with phase inverted electric field (PIE-PIE) to directly measure arbitrary ultrashort pulses in single-shot operation without using any retrieval algorithm. PIE-PIE utilizes highly efficient spectral phase conjugation based on four-wave-mixing. The ability to fully determine the spectrum, spectral phase, and CEP of relatively low intensity single-shot pulses will revolutionize ultrafast sciences and enable studies of arbitrary non-repeating ultrafast events.
The fields of photovoltaics, photodetection and light emission have seen tremendous activity in recent years with the advent of hybrid organic-inorganic perovskites. Yet, there have been far fewer ...reports of perovskite-based field-effect transistors. The lateral and interfacial transport requirements of transistors make them particularly vulnerable to surface contamination and defects rife in polycrystalline films and bulk single crystals. Here, we demonstrate a spatially-confined inverse temperature crystallization strategy which synthesizes micrometre-thin single crystals of methylammonium lead halide perovskites MAPbX
(X = Cl, Br, I) with sub-nanometer surface roughness and very low surface contamination. These benefit the integration of MAPbX
crystals into ambipolar transistors and yield record, room-temperature field-effect mobility up to 4.7 and 1.5 cm
V
s
in p and n channel devices respectively, with 10
to 10
on-off ratio and low turn-on voltages. This work paves the way for integrating hybrid perovskite crystals into printed, flexible and transparent electronics.
Two-photon absorption (TPA) is a nonlinear absorption process in semiconductors, creating a fast phase change in a low-intensity probe beam. Placing quantum-dots (QDs), on the other hand, in the ...active region of semiconductor optical amplifiers (SOAs) results in SOAs shorter carrier recovery time and lower gain saturation. Thus, in this article, the physical advantages of both TPA and QDs have been combined to numerically investigate the performance of all-optical NOT-OR (NOR) and exclusive-NOR (XNOR) logic gates, incorporating in Mach–Zehnder interferometers at a data rate of 2 Tb/s. The output quality factor (QF) of the considered Boolean functions against the key operational parameters is assessed and examined, including the impact of amplified spontaneous emission in order to obtain more realistic results. The overall QF in the presence of TPA is always higher than that without TPA.
Micro/nanoprocessing of graphene surfaces has attracted significant interest for both science and applications due to its effective modulation of material properties, which, however, is usually ...restricted by the disadvantages of the current fabrication methods. Here, by exploiting cylindrical focusing of a femtosecond laser on graphene oxide (GO) films, we successfully produce uniform subwavelength grating structures at high speed along with a simultaneous in situ photoreduction process. Strikingly, the well-defined structures feature orientations parallel to the laser polarization and significant robustness against distinct perturbations. The proposed model and simulations reveal that the structure formation is based on the transverse electric (TE) surface plasmons triggered by the gradient reduction of the GO film from its surface to the interior, which eventually results in interference intensity fringes and spatially periodic interactions. Further experiments prove that such a regular structured surface can cause enhanced optical absorption (>20%) and an anisotropic photoresponse (~0.46 ratio) for the reduced GO film. Our work not only provides new insights into understanding the laser-GO interaction but also lays a solid foundation for practical usage of femtosecond laser plasmonic lithography, with the prospect of expansion to other two-dimensional materials for novel device applications.
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