ABSTRACT
Utilizing hot carriers for efficient plasmonic-mediated chemical reactions (PMCRs) to convert solar energy into secondary energy is one of the most feasible solutions to the global environmental and energy crisis. Finding a plasmonic heterogeneous nanostructure with a more efficient and reasonable hot carrier transport path without affecting the intrinsic plasmonic properties is still a major challenge that urgently needs to be solved in this field. Herein, the mechanism by which plasmonic-promoted interatomic hot electron redistribution on the surface of Au3Cu alloy nanoparticles promotes the electrocatalytic nitrogen reduction reaction (ENRR) is successfully clarified. The localized surface plasmon resonance (LSPR) effect can boost the transfer of plasmonic hot electrons from Au atoms to Cu atoms, trigger the interatomic electron regulation of Au3Cu alloy nanoparticles, enhance the desorption of ammonia molecules, and increase the ammonia yield by approximately 93.9%. This work provides an important reference for rationally designing and utilizing the LSPR effect to efficiently regulate the distribution and mechanism of plasmonic hot carriers on the surface of heterogeneous alloy nanostructures.
ABSTRACT
Plasmons have facilitated diverse analytical applications due to the boosting signal detectability by hot spots. In practical applications, it is crucial to fabricate straightforward, large-scale, and reproducible plasmonic substrates. Dewetting treatment, via applying direct thermal annealing of metal films, has been used as a straightforward method in the fabrication of such plasmonic nanostructures. However, tailoring the evolution of the dewetting process of metal films poses considerable experimental complexities, mainly due to nanoscale structure formation. Here, we use grazing-incidence small- and wide-angle X-ray scattering for the in situ investigation of the high-power impulse magnetron sputter deposition of Ag on self-assembled Au nanoparticle arrays at low-temperature dewetting conditions. This approach allows us to examine both the direct formation of binary Au/Ag nanostructure and the consequential impact of the dewetting process on the spatial arrangement of the bimetallic nanoparticles. It is observed that the dewetting at 100 °C is sufficient to favor the establishment of a homogenized structural configuration of bimetallic nanostructures, which is beneficial for localized surface plasmon resonances (LSPRs). The fabricated metal nanostructures show potential application for the surface-enhanced Raman scattering (SERS) detection of rhodamine 6G molecules. As SERS platform, bimetallic nanostructures formed with dewetting conditions turn out to be superior to those without dewetting conditions. The method in this work is envisioned as a facile strategy for the fabrication of plasmonic nanostructures.
ABSTRACT
This work studies the real gas effects on the autoignition of hydrocarbon fuels under high pressures, using normal dodecane (n-dodecane) as the representative fuel and the Redlich-Kwong equation of state (EoS) as the real gas description. It is demonstrated that the real gas description yields a shorter ignition delay time (IDT) compared with the ideal gas description, especially in low-temperature regimes which could encompass the negative temperature coefficient (NTC) phenomena and has a stronger dependence on the molecular volume than the attractive potential. The study further shows that high pressure facilitates low-temperature reaction pathways, where the compressibility factors of key reactants contribute to real gas effects. Moreover, the results suggest that accounting for real gas behavior leads to an increase in the formation of polycyclic aromatic hydrocarbons (PAHs), which, in turn, promotes soot generation.
ABSTRACT
The stink bug Arma custos (Hemiptera: Pentatomidae) is a predatory enemy successfully used for biocontrol of lepidopteran and coleopteran pests in notorious invasive species. In this study, a high-quality chromosome-scale genome assembly of A. custos was achieved through a combination of Illumina sequencing, PacBio HiFi sequencing, and Hi-C scaffolding techniques. The final assembled genome was 969.02 Mb in size, with 935.94 Mb anchored to seven chromosomes, and a scaffold N50 length of 135.75 Mb. This genome comprised 52.78% repetitive elements. The detected complete BUSCO score was 99.34%, indicating its completeness. A total of 13,708 protein-coding genes were predicted in the genome, and 13219 of them were annotated. This genome provides an invaluable resource for further research on various aspects of predatory bugs, such as biology, genetics, and functional genomics.
Subject(s)
Genome, Insect , Heteroptera , Animals , Heteroptera/genetics , Chromosomes, InsectABSTRACT
Iatrogenic nerve injury is a significant complication in surgery, which can negatively impact patients' quality of life. Currently, the main clinical neuroimaging methods, such as computed tomography, magnetic resonance imaging, and high-resolution ultrasonography, do not offer precise real-time positioning images for doctors during surgery. The clinical application of optical molecular imaging technology has led to the emergence of new concepts such as optical molecular imaging surgery, targeted surgery, and molecular-guided surgery. These advancements have made it possible to directly visualize surgical target areas, thereby providing a novel method for real-time identification of nerves during surgery planning. Unlike traditional white light imaging, optical molecular imaging technology enables precise positioning and identifies the cation of intraoperative nerves through the presentation of color images. Although a large number of experiments and data support its development, there are few reports on its actual clinical application. This paper summarizes the research results of optical molecular imaging technology and its ability to realize neural visualization. Additionally, it discusses the challenges neural visualization recognition faces and future development opportunities.
ABSTRACT
Current 3D printed electrodes suffer from insufficient multiscale transport speed, which limits the improvement of electrochemical performance of 3D printed electrodes. Herein, a bioinspired hierarchical fast transport network (HFTN) in a 3D printed reduced graphene oxide/carbon nanotube (3DP GC) electrode demonstrating superior electrochemical performance is constructed. Theoretical calculations reveal that the HFTN of the 3DP GC electrode increases the ion transport rate by more than 50 times and 36 times compared with those of the bulk GC electrode and traditional 3DP GC (T-3DP GC) electrode, respectively. Compared with carbon paper, carbon cloth, bulk GC electrode, and T-3DP GC electrode, the HFTN in 3DP GC electrode endows obvious advantages: i) efficient utilization of surface area for uniform catalysts dispersion during electrochemical deposition; ii) efficient utilization of catalysts enables the high mass activity of catalysts and low overpotential of electrode in electrocatalytic reaction. The cell of 3DP GC/Ni-NiO||3DP GC/NiS2 demonstrates a low voltage of only 1.42 V to reach 10 mA cm-2 and good stability up to 20 h for water splitting in alkaline conditions, which is superior to commercialized Pt/C||RuO2 . This work demonstrates great potential in developing high-performance 3D printed electrodes for electrochemical energy conversion and storage.
Subject(s)
Nanotubes, Carbon , Water , Electrodes , Catalysis , Printing, Three-DimensionalABSTRACT
Anisotropic 3D nanostructures exhibit excellent electrocatalytic activity and stability due to their heterogeneous elemental distribution and unsymmetrical configuration. However, it is still a huge challenge to combine anisotropically distributed elements and anisotropic morphologies within one 3D nanostructure. Herein, 3D Au@Pt-Pd hemispherical nanostructures (Au@Pt-Pd H-Ss) are fabricated as highly efficient electrocatalysts for oxidation reaction, which present heterogenous element distribution and anisotropic morphology. It is demonstrated that the non-uniform adsorption of BO2 - on Au-CTA+ surface, as well as the simulated lower formation energy of Pt-Pd atoms for Au-CTA+ -BO2 - , basically contribute to the eventual formation of Au@Pt-Pd H-Ss. Impressively, the unique anisotropic Au@Pt-Pd H-Ss exhibit superior electrocatalytic activity and durability for methanol, ethanol, and formic acid oxidation reaction compared with commercial Pt/C and previously reported noble-metal based electrocatalysts. Especially, the mass activity of Au@Pt-Pd H-Ss for MOR is 4.38 A mgPt+Pd -1 , which is about 2.0 and 4.7 times that of Au@Pt-Pd spherical nanostructures (Au@Pt-Pd Ss) and commercial Pt/C catalyst, respectively. This work provides an important reference for the design and preparation of 3D anisotropic and high-efficiency electrocatalysts.
ABSTRACT
Recognizing that low-temperature ignition of alkanes is usually associated with one heat release peak, we report herein that, for iso-octane under certain ranges of initial temperatures and pressures, two separate heat release peaks were observed through computational simulations using several kinetic mechanisms. The inherent chemical reason for this phenomenon is discussed using reaction channel analysis and is identified to result from the competition between R + O2 â RO2 and the ß scission reactions. By further utilizing sensitivity and path flux analyses, an isomeric effect is identified in that the different isomeric structures produced through the H-abstraction reactions can lead to differences in the subsequent low-temperature reaction pathways.
ABSTRACT
Electrochemical nitrogen reduction reaction (NRR) provides a facile and sustainable strategy to produce ammonia (NH3) at ambient conditions. However, the low NH3 yield and Faradaic efficiency (FE) are still the main challenges due to the competitive hydrogen evolution reaction (HER). Herein, a three-phase electrocatalyst through in situ fabrication of Au nanoparticles (NPs) located on hydrophobic carbon fiber paper (Au/o-CFP) is designed. The hydrophobic CFP surface facilitates efficient three-phase contact points (TPCPs) for N2 (gas), electrolyte (liquid), and Au NPs (solid). Thus, concentrated N2 molecules can contact the electrocatalyst surface directly, inhibiting the HER since the lowered proton concentration and overall enhancing NRR. The three-phase Au/o-CFP electrocatalyst presents an excellent NRR performance with high NH3 yield rate of 40.6 µg h-1 mg-1 at -0.30 V and great FE of 31.3% at -0.10 V versus RHE (0.1 m Na2SO4). The N2-bubble contact angle result and cyclic voltammetry analysis confirm that the hydrophobic interface has a relatively strong interaction with N2 bubble for enhanced NRR and weak electrocatalytic activity for HER. Significantly, the three-phase Au/o-CFP exhibits excellent stability with a negligible fluctuation of NH3 yield and FE in seven-cycle test. This work provides a new strategy for improving NRR and simultaneously inhibiting HER.
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Plasmonic metal nanostructures offer the unique ability to effectively enhance sunlight harvesting by localized surface plasmon resonance (LSPR), which can induce direct photocatalytic reactions. However, only metal nanoparticles with a relatively low magnitude of electromagnetic field enhancement usually require a high illumination intensity to ensure the catalytic performance, which greatly limits the solar photocatalytic efficiency. Herein, we designed plasmonic Au nanoparticle film with high electromagnetic field enhancement to achieve high-efficiency catalytic activity under low-power NIR light illumination. This work minimized the influence of the photothermal effect on the reaction by using a low illumination intensity and further revealed the main contribution of plasmon-excited hot electrons to the photochemical reaction. This study provides important insights into the study of the mechanism of LSPR in photocatalytic reactions and further improves the efficiency of solar energy utilization.
ABSTRACT
Plasmonic nanomaterials are excellent and promising building blocks for information encoding and decoding. However, the positioning of multiplexed nanomaterials into recognizable structures remains a major challenge in nanotechnology. Herein, we developed a novel method for fabricating diversified nanostructures through surface charge inversion from amino-modified substrates to carboxyl-modified ones, as well as the corresponding electrostatic-induced assembly of metal nanoparticles. Under optimal conditions, the selected gold nanospheres (NSs) and peanut-like gold nanorods were successively located into patterns of spaced lines on the same substrate. Due to their unique optical properties, these two types of designed nanoarrays exhibited distinct color contrast and spectrum difference under dark-field scattering microscopy. Furthermore, this general strategy can be extended to wide ranges of nanoparticles with different morphologies and compositions for other multifunctional and high-demanding encoding applications.
ABSTRACT
Low solar light absorption and high electron-hole pair recombination are still the main challenges for solar energy conversion. Here, we design a plasmonic nanoparticle (NP)-film with a unique structure combining the advantages of a Au NP and film, which exhibits strong broadband absorption from the visible to near-infrared (NIR) wavelength range. In addition, the high density of sub-1 nm inter-particle gaps in the Au NP-film supports electromagnetic field enhancement of several orders of magnitude that greatly promotes the generation and separation of electron-hole pairs. Accordingly, the plasmonic NP-film-assisted photocatalyst (TiO2/90Au/TiO2) leads to an 88-fold increase in the photocurrent density at 0.75 V vs. RHE in 25% methanol solution under visible-NIR light irradiation (λ > 420 nm) compared to a TiO2 film, which is higher than those of the ever reported Au/TiO2 photocatalysts in the entire visible-NIR range. Our finding indicates a promising way to explore full solar spectrum photocatalysts, which can be easily extended to other energy conversion applications.
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Genotyping of the hepatitis C virus (HCV) is crucial for determining the most efficient anti-viral therapy. The clinical sensitivity and specificity of the IntelliPlexTM HCV Genotyping Kit was determined by comparing the assay results of 307 specimens with the results obtained by Sanger sequencing. Out of 202 HCV-positive specimens tested, 8 samples yielded discrepant results between the IntelliPlex HCV Genotyping Kit and Sanger sequencing. For 5 of these discrepant samples, the IntelliPlex HCV Genotyping Kit classified the correct genotype but failed to show the same single or dual infected status as determined by Sanger sequencing. A total of 105 samples which tested negative for HCV by In-Vitro-Diagnostics (IVD)-approved viral load assay tested negative for HCV by the IntelliPlex HCV Genotyping Kit. The IntelliPlex HCV Genotyping Kit has a clinical specificity of 100% and a clinical sensitivity of 96.9% and is suited to be used in clinical laboratories to genotype HCV.
Subject(s)
Genotyping Techniques/standards , Hepacivirus/genetics , Hepatitis C/diagnosis , Reagent Kits, Diagnostic/standards , Genotype , Hepatitis C/virology , Humans , RNA, Viral/genetics , Sensitivity and Specificity , Viral LoadABSTRACT
This article reviews recent theoretical developments on incipient ignition induced by radical runaway in systems described by detailed chemistry. Employing eigenvalue analysis, we first analyze the canonical explosion limits of mixtures of hydrogen and oxygen, yielding explicit criteria that well reproduce their characteristic Z-shaped response in the pressure-temperature plot. Subsequently, we evaluate the role of hydrogen addition to the explosion limits of mixtures of oxygen with either carbon monoxide or methane, demonstrating and quantifying its strong catalytic effect, especially for the carbon monoxide cases. We then discuss the role of low-temperature chemistry in the autoignition of large hydrocarbon fuels, with emphasis on the first-stage ignition delay and the associated negative-temperature coefficient phenomena. Finally, we extend the analysis to problems of nonhomogeneous ignition in the presence of convective-diffusive transport, using counterflow as an example, demonstrating the canonical similarity between homogeneous and nonhomogeneous systems. We conclude with suggestions for potential directions for future research.
Subject(s)
Fire Extinguishing Systems , Free Radicals/chemistry , Carbon Monoxide/chemistry , Hydrocarbons/chemistry , Hydrogen/chemistry , Kinetics , Oxygen/chemistry , Pressure , TemperatureABSTRACT
The ignition boundary of hydrogen/oxygen mixtures is a Z-shaped curve in the pressure-temperature space, demonstrating the existence of three explosion limits. In this study, a general analysis governing all the three explosion limits in an isothermal environment is performed by considering both linear chain reactions (reactant-radical reactions) and nonlinear chain reactions (radical-radical reactions), in addition to the zeroth-order reactant-reactant reactions. For the nonlinear reactions, it is further shown that the linear-nonlinear coupling has the major influence, while the effect of nonlinear-nonlinear coupling is negligible. Phenomenologically, at low pressures, the competition between linear branching and linear termination as well as wall destruction determines the first and second explosion limits, while the nonlinear chain reactions are unimportant because of the small radical concentrations under these conditions. However, at higher pressures, both linear and nonlinear chain reactions are needed to accurately describe the third limit, which would be underpredicted by considering the linear chain reactions alone. For intermediate and high pressures, the dominant species are HO2 and H2O2, respectively. Mechanistically, the concentration of HO2 becomes higher at higher pressures due to the three-body recombination reaction, H + O2 + M â HO2 + M, such that the radical-radical reactions involving HO2 become important, while the reaction HO2 + HO2 â H2O2 + O2 renders HO2 nonessential at the third limit, with the H2O2 radical generated by the nonlinear chain reactions becoming the controlling species.
ABSTRACT
Culex flavivirus (CxFV) is an insect-specific virus of the genus Flavivirus. CxFV strains have been isolated from Cx. pipiens, Cx. quinquefasciatus, and other Cx. species in Asia, Africa, North America, Central America and South America. CxFV was isolated for the first time in China in 2006. As this is a novel flavivirus, we explored the distribution and genetic characteristics of Culex flavivirus in China. A total of 46,649 mosquitoes were collected in seven provinces between 2004 and 2012 and were analysed in 871 pools. 29 CxFV RNAs from Cx. pipiens, Cx. tritaeniorhynchus, Anopheles Sinensis, and Culex spp. tested positive for CxFV in real-time RT-PCR. 6 CxFV strains were isolated from Cx. species collected in Shandong, Henan, and Shaanxi provinces, while no virus or viral RNA was detected in samples from Sichuan, Chongqing, Hubei, and Fujian. Phylogenetic analysis of the envelope gene indicated that Chinese strains formed a robust subgroup of genotype 1, together with viruses from the United States and Japan. This study demonstrates that the geographic distribution of CxFV in China is widespread, but geographical boundaries to spread are apparent. Our findings suggest that CxFV can infect various mosquito species in nature.
Subject(s)
Anopheles/virology , Culex/virology , Flavivirus/isolation & purification , Phylogeography , Animals , China , Cluster Analysis , Female , Flavivirus/genetics , Genotype , Real-Time Polymerase Chain Reaction , Sequence Analysis, DNA , Viral Envelope Proteins/geneticsABSTRACT
Although the polymorphisms of PTPN22 and the variants of CTLA-4 have been reported to be the susceptibility genes, which increased risk of latent autoimmune diabetes in adults (LADA), the results remained inconclusive. The aim of this meta-analysis was to evaluate the association between the polymorphisms of two genes and LADA. We performed a systematic review by identifying relevant studies and applied meta-analysis to pool gene effects. Data from ten studies published between 2001 and 2013 were pooled for two polymorphisms: rs2476601 in the PTPN22 gene and rs231775 in the CTLA-4 gene. Data extraction and assessments for risk of bias were independently performed by two reviewers. Fixed-effect model and random-effect model were used to pool the odds ratios; meanwhile, heterogeneity test, publication bias and sensitive analysis were explored. The minor T allele at rs2476601 and the minor G at rs231775 carried estimated relative risks (odds ratio) of 1.52 (95 % CI 1.29-1.79) and 1.39 (95 % CI 1.11-1.74), respectively. These alleles contributed to an absolute lowering of the risk of all LADA by 4.88 and 14.93 % when individuals do not carry these alleles. The estimated lambdas were 0.49 and 0.63, suggesting a codominant model of effects was most likely for two genes. In summary, our systematic review has demonstrated that PTPN22 rs2476601 and CTLA-4 rs231775 are potential risk factors for LADA. An updated meta-analysis is required when more studies are published to increase the power of these polymorphisms and LADA.