33 research outputs found
Novel layered 2D materials for ultrafast photonics
A range of new 2D materials have recently been reported, including topological insulators, transitionmetal dichalcogenides, black phosphorus, MXenes, and metal-organic frameworks, which have demonstrated high optical nonlinearity and Pauli blocking for widespread use as saturable absorbers in pulsed lasers. 2D materials are emerging as a promising platform for ultrashort- pulse fiber laser technology. This review presents
a catalog of the various pulsed laser applications based on the series of emerging 2D materials. In addition, novel optical devices using layered materials, such as optical
modulators, optical switches, and all-optical devices, are also included. It is anticipated that the development of 2D materials will intensify in the future, providing potentially
new and wide-ranging efficacy for 2D materials in ultrafast photonic technology
High-sensitivity salinity sensor based on optical microfiber coil resonator
A simple, compact, and high-sensitivity optical sensor for salinity measurement is
reported based on an optical microfiber coil resonator (MCR). The MCR is manufactured by
initially wrapping microfiber on a polymethylmethacrylate (PMMA) rod, which is dissolved
to leave a hollow cylindrical fluidic channel within the coil for measurement. Based on the
light propagation through the MCR, the device’s spectrum moves to long wavelengths with
increased salinity in the fluid. The MCR device’s sensitivity can reach up to 15.587 nm/%
with a resolution of 1.28 Ă— 10-3%. It is also confirmed that the temperature dependence is
79.87 pm/°C, which results from the strong thermal-expansion coefficient of the low
refractive index epoxy. The experimental results indicate that the device can be widely used
as a high sensitivity salinity sensor in water and other liquids due to its stability, compactness,
electromagnetic immunity, and high sensitivity
Insights into Shape Selectivity and Acidity Control in NiO-Loaded Mesoporous SBA-15 Nanoreactors for Catalytic Conversion of Cellulose to 5‑Hydroxymethylfurfural
Facilitated isomerization of cellulose
hydrolysis intermediate
glucose without unexpected byproducts, which is the rate-determining
step in the production of high-value-added biofuels, enables the efficient
production of 5-hydroxymethylfurfural (5-HMF) from cellulose. In this
work, considering the essential role of the acidity control and shape
selectivity of a zeolite catalyst, a NiO-loaded mesoporous NiO/poly(vinyl
pyrrolidone) (PVP)-phosphotungstic acid (HPA)@SBA-15 nanoreactor was
prepared. This SBA-15 nanoreactor with a pore size of 5.47 nm reduced
the concentration of byproducts formic acid (FA) and levulinic acid
(LA) through shape selection for intermediates. Well-defined NiO nanoparticles
(Ni-to-carrier mass ratio was 1:1) provided the NiO/PVP-HPA@SBA-15
nanoreactor a high Lewis acidity of 99.29 μmol g–1 for glucose catalytic isomerization, resulting in an increase in
total reducing sugar (TRS) yield by 5 times. Such a nanoreactor remarkably
improved the reaction efficiency of 5-HMF production from cellulose
(a 5-HMF selectivity of 95.81%) in the 1-butyl-3-methylimidazolium
chloride ([BMIM]Cl)/valerolactone (GVL) biphasic system
Efficient Genome Editing in Most <i>Staphylococcus aureus</i> by Using the Restriction-Modification System Silent CRISPR-Cas9 Toolkit
Staphylococcus aureus is
a clinically
important pathogen that threatens human health due to its strong pathogenicity
and drug resistance, leading to meningitis, endocarditis, and skin
and soft tissue infections. Genetic manipulation in S. aureus is a powerful approach for characterizing
the molecular mechanisms of bacterial drug resistance, pathogenicity,
and virulence. However, a strong restriction barrier presents a major
obstacle to the extensive utilization of genetic manipulation tools
in clinical isolates of S. aureus. Here, we constructed a restriction-modification (RM) system silent
CRISPR-Cas9 toolkit that synonymously eliminated the type I RM targets
of S. aureus from plasmids, downsized
plasmids using minicircle technology, and combined with a plasmid
artificial modification (PAM) method to circumvent the type II RM
system. The RM-silent CRISPR-Cas9 toolkit enables a significant improvement
in transformation (105–106 transformants
per microgram plasmid in strains we tested) and high-success efficiency
editing for gene deletion (knockout strain obtained in one-round electroporation)
in a wide range of S. aureus species
including clinical isolates of unknown genetic background. The RM-silent
CRISPR-Cas9 toolkits could expedite the process of mutant construction
in most S. aureus strains, and
this approach could be applied to the design of other genetic toolkit
plasmids for utilization in a wider range of S. aureus strains
Investigation of temperature dependence of microfibre coil resonators
The temperature-sensitive performance of a microfibre coil resonator (MCR) is thoroughly investigated. The MCR is fabricated by wrapping a microfibre on a PMMA rod coated with a UV-curable low refractive index epoxy. The temperature sensitivity is measured by investigating the correlation between the shift of the resonant wavelength and the surrounding temperature. It is determined that a range of parameters of the MCRs, including the gap between two adjacent rings, the diameter of the supporting rod, the number of rings, and the diameter of the microfibre have a great influence on the temperature sensitivity of the MCRs. By optimizing the fabrication parameters of MCRs, such as the gap of the adjacent microrings and the diameter of supporting rod etc, the maximum temperature sensitivity obtained is 237.31 pm/oC, which is about 2.3 times higher than that of MCR embedded in EFIRON UV-373 polymer and 23 times higher than that of MCR embedded in Teflon because of the strong thermo-optic and thermal expansion effects of the low refractive index epoxy and the supporting rod used in the experiments. Theoretical (numerical) simulation and experiment results are considered in the assessment of the optical performance improvement of MCR-based optical fibre temperature sensors
Fabrication of Supported Cuprous Sites at Low Temperatures: An Efficient, Controllable Strategy Using Vapor-Induced Reduction
Selective
reduction of supported CuO to Cu<sub>2</sub>O was realized
using the strategy of vapor-induced reduction, in which HCHO/H<sub>2</sub>O vapor diffuses into the pores of the support and interacts
with predispersed CuO. This new strategy allows the fabrication of
supported cuprous sites at much lower temperatures within a short
time, avoids the formation of Cu(0) with a CuÂ(I) yield of nearly 100%,
and results in materials with good adsorption performance, which is
impossible to achieve by conventional methods
Efficient Genome Editing in Most <i>Staphylococcus aureus</i> by Using the Restriction-Modification System Silent CRISPR-Cas9 Toolkit
Staphylococcus aureus is
a clinically
important pathogen that threatens human health due to its strong pathogenicity
and drug resistance, leading to meningitis, endocarditis, and skin
and soft tissue infections. Genetic manipulation in S. aureus is a powerful approach for characterizing
the molecular mechanisms of bacterial drug resistance, pathogenicity,
and virulence. However, a strong restriction barrier presents a major
obstacle to the extensive utilization of genetic manipulation tools
in clinical isolates of S. aureus. Here, we constructed a restriction-modification (RM) system silent
CRISPR-Cas9 toolkit that synonymously eliminated the type I RM targets
of S. aureus from plasmids, downsized
plasmids using minicircle technology, and combined with a plasmid
artificial modification (PAM) method to circumvent the type II RM
system. The RM-silent CRISPR-Cas9 toolkit enables a significant improvement
in transformation (105–106 transformants
per microgram plasmid in strains we tested) and high-success efficiency
editing for gene deletion (knockout strain obtained in one-round electroporation)
in a wide range of S. aureus species
including clinical isolates of unknown genetic background. The RM-silent
CRISPR-Cas9 toolkits could expedite the process of mutant construction
in most S. aureus strains, and
this approach could be applied to the design of other genetic toolkit
plasmids for utilization in a wider range of S. aureus strains
Additional file 1 of Interaction of immune cells with renal cancer development: Mendelian randomization (MR) study
Supplementary Material 1
Data_Sheet_1_Of its five acyl carrier proteins, only AcpP1 functions in Ralstonia solanacearum fatty acid synthesis.docx
The fatty acid synthesis (FAS) pathway is essential for bacterial survival. Acyl carrier proteins (ACPs), donors of acyl moieties, play a central role in FAS and are considered potential targets for the development of antibacterial agents. Ralstonia solanacearum, a primary phytopathogenic bacterium, causes bacterial wilt in more than 200 plant species. The genome of R. solanacearum contains five annotated acp genes, acpP1, acpP2, acpP3, acpP4, and acpP5. In this study, we characterized the five putative ACPs and confirmed that only AcpP1 is involved in FAS and is necessary for the growth of R. solanacearum. We also found that AcpP2 and AcpP4 participate in the polyketide synthesis pathway. Unexpectedly, the disruption of four acp genes (acpP2, acpP3, acpP4, and acpP5) allowed the mutant strain to grow as well as the wild-type strain, but attenuated the bacterium’s pathogenicity in the host plant tomato, suggesting that these four ACPs contribute to the virulence of R. solanacearum through mechanisms other than the FAS pathway.</p
Designed Synthesis and Electrochemical Performance Regulation of the Hierarchical Hollow Structure Cu<sub>2</sub>S/Cu<sub>7</sub>S<sub>4</sub>/NC Anode for Hybrid Supercapacitors
Copper-based compounds have attracted increasing attention
as electrode
materials for rechargeable devices, but their poor conductivity and
insufficient stability inhibit their further development. Herein,
an effective method has been proposed to improve the electrochemical
properties of the copper-based electrodes by coating carbon materials
and generating unique micro/nanostructures. The prepared Cu2S/Cu7S4/NC with hierarchical hollow structure
possesses excellent electrochemical performance, attributing to the
composition and structure optimization. The superior charge storage
performance has been assessed by theoretical and experimental research.
Specifically, the Cu2S/Cu7S4/NC exhibits
remarkably higher electrical conductivity and lower adsorption-free
energy for O* and OH* than those of Cu2O. Moreover, the
Cu2S/Cu7S4/NC delivers a high specific
capacitance of 1261.3 F·g–1 at the current
density of 1 A·g–1 and also has great rate
performance at higher current densities, which are much better than
those of the Cu2O nanocubes. In addition, the assembled
hybrid supercapacitor using Cu2S/Cu7S4/NC as the anode exhibits great energy density, power density, and
cycling stability. This study has proposed a novel and feasible method
for the synthesis of high-performance copper-based electrodes and
their electrochemical performance regulation, which is of great significance
for the advancement of high-quality electrode materials and rechargeable
devices