Hot Electrons in a Steady State: Interband vs Intraband Excitation of Plasmonic Gold.

Understanding the dynamics of "hot", highly energetic electrons resulting from nonradiative plasmon decay is crucial for optimizing applications in photocatalysis and energy conversion. This study presents an analysis of electron kinetics within plasmonic metals, focusing on the steady-state behavior during continuous-wave (CW) illumination. Using an inelastic spectroscopy technique, we quantify the temperature and lifetimes of distinct carrier populations during excitation. A significant finding is the monotonic increase in hot electron lifetime with decreases in electronic temperature. We also observe a 1.22× increase in hot electron temperature during intraband excitation compared to interband excitation and a corresponding 2.34× increase in carrier lifetime. The shorter lifetimes during interband excitation are hypothesized to result from direct recombination of nonthermal holes and hot electrons, highlighting steady-state kinetics. Our results help bridge the knowledge gap between ultrafast and steady-state spectroscopies, offering critical insights for optimizing plasmonic applications.

Mechanisms of Photothermalization in Plasmonic Nanostructures: Insights into the Steady State.

Localized surface plasmon resonances (LSPRs) in metallic nanostructures result in subwavelength optical confinement that enhances light-matter interactions, for example, aiding the sensitivity of surface spectroscopies. The dissipation of surface plasmons as electronic and vibrational excitations sets the limit for field confinement but also provides opportunities for photochemistry, photocatalysis, and photothermal heating. Optimization for either goal requires a deeper understanding of this photothermalization process. In this review, we focus on recent insights into the physics and dynamics governing photothermalization of LSPRs in metallic nanostructures, emphasizing comparisons between the steady-state behavior and ultrafast time-resolved studies. The differences between these regimes inform how to best optimize plasmonic systems for applications under relatively low-intensity, continuous illumination (e.g., sunlight).

Plasmonic Photocatalysis with Nonthermalized Hot Carriers.

Hot carriers generated by plasmonic damping have been suggested to promote photocatalysis, yet it remains unclear how the nonthermalized hot carriers dynamically activate and promote the energy transfer processes. Here, we present an Anderson-Newns model to describe the vibrational excitation and bond dissociation induced by plasmonic hot carriers. The nonthermal distribution of the hot carriers generated by plasmon damping is accounted for on equal footing with thermal carriers at a given temperature in the electron-molecule scattering. We found that the nonthermal electrons in the high energy region can, albeit in much smaller populations, provide an efficient and dominant channel for photodissociation especially in the low-temperature and quantum plasmon regime. Our model captures the wavelength dependence and reproduces the enhancement factors observed by experiments for oxygen dissociation on silver nanoparticles. It also paves a way to harvesting nonthermal plasmonic energy for photocatalysis in the quantum regime.

Rapid Generation of Hierarchically Porous Metal-Organic Frameworks through Laser Photolysis.

Hierarchically porous metal-organic frameworks (HP-MOFs) facilitate mass transfer due to mesoporosity while preserving the advantage of microporosity. This unique feature endows HP-MOFs with remarkable application potential in multiple fields. Recently, new methods such as linker labilization for the construction of HP-MOFs have emerged. To further enrich the synthetic toolkit of MOFs, we report a controlled photolytic removal of linkers to create mesopores within microporous MOFs at tens of milliseconds. Ultraviolet (UV) laser has been applied to eliminate "photolabile" linkers without affecting the overall crystallinity and integrity of the original framework. Presumably, the creation of mesopores can be attributed to the missing-cluster defects, which can be tuned through varying the time of laser exposure and ratio of photolabile/robust linkers. Upon laser exposure, MOF crystals shrank while metal oxide nanoparticles formed giving rise to the HP-MOFs. In addition, photolysis can also be utilized for the fabrication of complicated patterns with high precision, paving the way towards MOF lithography, which has enormous potential in sensing and catalysis.

A prospective, randomised double-blind study on the anaesthetic effect of dexmedetomidine hydrochloride in brainstem tumour surgery.

CONTEXT: Brainstem tumour surgery is difficult, and accidents can easily occur. OBJECTIVE: To explore the effect of dexmedetomidine hydrochloride on brainstem tumour surgery. DESIGN, SETTING AND PARTICIPANTS: A total of 60 patients with brainstem tumours successfully operated on by our hospital from March 2016 to March 2018 were selected as subjects. INTERVENTIONS: These patients were randomised into two groups: the research group (n = 30) and control group (n = 30). Patients in the control group were given propofol together with a placebo (0.9% sodium chloride solution) to maintain anaesthesia after general anaesthesia, while patients in the research group were supplemented with dexmedetomidine hydrochloride. MAIN OUTCOME MEASURE: Awakening time, overall stability of various indicators in the operation and adverse reactions during the awakening period were observed. RESULTS: The results revealed that patients in the research group had a longer awakening time, higher mean stability rate, higher effective rate and less incidence of adverse reactions during the awakening period than the control group; the differences were all statistically significant (P < 0.05). CONCLUSION: Dexmedetomidine hydrochloride has a good analgesic effect in intraoperative anaesthesia during brainstem tumour surgery, which significantly reduces the incidence of adverse reactions. Therefore, it can be used to assist anaesthesia during brainstem tumour operations and is worthy of clinical popularisation and application.

In Situ Synthesis and Unprecedented Electrochemical Performance of Double Carbon Coated Cross-Linked Co3O4.

Improving the structural stability and the electron/ion diffusion rate across whole electrode particles is crucial for transition metal oxides as next-generation anodic materials in lithium-ion batteries. Herein, we report a novel structure of double carbon-coated Co3O4 cross-linked composite, where the Co3O4 nanoparticle is in situ covered by nitrogen-doped carbon and further connected by carbon nanotubes (Co3O4 NP@NC@CNTs). This double carbon-coated Co3O4 NP@NC@CNTs framework not only endows a porous structure that can effectively accommodate the volume changes of Co3O4, but also provides multidimensional pathways for electronic/ionic diffusion in and among the Co3O4 NPs. Electrochemical kinetics investigation reveals a decreased energy barrier for electron/ion transport in the Co3O4 NP@NC@CNTs, compared with the single carbon-coated Co3O4 NP@NC. As expected, the Co3O4 NP@NC@CNT electrode exhibits unprecedented lithium storage performance, with a high reversible capacity of 1017 mA h g-1 after 500 cycles at 1 A g-1, and a very good capacity retention of 75%, even after 5000 cycles at 15 A g-1. The lithiation/delithiation process of Co3O4 NP@NC@CNTs is dominated by the pseudocapacitive behavior, resulting in excellent rate performance and durable cycle stability.

Nanoscale Artificial Plasmonic Lattice in Self-Assembled Vertically Aligned Nitride-Metal Hybrid Metamaterials.

Nanoscale metamaterials exhibit extraordinary optical properties and are proposed for various technological applications. Here, a new class of novel nanoscale two-phase hybrid metamaterials is achieved by combining two major classes of traditional plasmonic materials, metals (e.g., Au) and transition metal nitrides (e.g., TaN, TiN, and ZrN) in an epitaxial thin film form via the vertically aligned nanocomposite platform. By properly controlling the nucleation of the two phases, the nanoscale artificial plasmonic lattices (APLs) consisting of highly ordered hexagonal close packed Au nanopillars in a TaN matrix are demonstrated. More specifically, uniform Au nanopillars with an average diameter of 3 nm are embedded in epitaxial TaN platform and thus form highly 3D ordered APL nanoscale metamaterials. Novel optical properties include highly anisotropic reflectance, obvious nonlinear optical properties indicating inversion symmetry breaking of the hybrid material, large permittivity tuning and negative permittivity response over a broad wavelength regime, and superior mechanical strength and ductility. The study demonstrates the novelty of the new hybrid plasmonic scheme with great potentials in versatile material selection, and, tunable APL spacing and pillar dimension, all important steps toward future designable hybrid plasmonic materials.

Morphology Controllable Synthesis of NiO/NiFe2O4 Hetero-Structures for Ultrafast Lithium-Ion Battery.

Rational design of high performance anode material with outstanding rate capability and cycling stability is of great importance for lithium ion batteries (LIBs). Herein, a series of NiO/NiFe2O4 hetero-structures with adjustable porosity, particle size, and shell/internal structure have been synthesized via a controllable annealing process. The optimized NiO/NiFe2O4 (S-NFO) is hierarchical hollow nanocube that is composed of ~5 nm subunits and high porosity. When being applied as anode for LIBs, the S-NFO exhibits high rate capability and excellent cycle stability, which remains high capacity of 1,052 mAh g-1 after 300 cycles at 5.0 A g-1 and even 344 mAh g-1 after 2,000 cycles at 20 A g-1. Such impressive electrochemical performance of S-NFO is mainly due to three reasons. One is high porosity of its hierarchical hollow shell, which not only promotes the penetration of electrolyte, but also accommodates the volume change during cycling. Another is the small particle size of its subunits, which can effectively shorten the electron/ion diffusion distance and provide more active sites for Li+ storage. Besides, the hetero-interfaces between NiO and NiFe2O4 also contribute toitsfast charge transport.

[The clinical significance of S100ß protein in cerebrospinal fluid and serum from the patients with cerebral hemorrhage].

AIM: To observe the change and the clinical significance of S100ß protein level in cerebrospinal fluid and serum from the patients with cerebral hemorrhage (CH). METHODS: ELISA was used to detect the expression of S100ß protein in CSF and serum from CH patients control with Inguinal Hernia or great saphenous varix patients. Meanwhile, rabbit CH model at 6 h, 12 h, 24 h, 48 h, 72 h and 96 h . RESULTS: The levels of CSF S100ß protein at acute stage of CH patients increased significantly compared with those at recovery stage of CH patients and control group(P<0.01). The levels of S100ß protein in CSF from CH patients increased significantly compared with those in serum (P<0.01).The levels of S100ß protein in CSF of rabbit experimental group increased significantly compared with those of sham operation group at different time points(P<0.01). CONCLUSION: The level of S100ß protein in CSF from CH patients increases. It may be a biomarker as reflecting degree of pathogenetic and predicting outcome in the CH patients.