Regulation of Hot Electrons Transport Achieved through Controlled Electron-Phonon Coupling in Metallic Heterostructures.

The electron-phonon (e-ph) interactions are pivotal in shaping the electrical and thermal properties, and in particular, determining the carrier dynamics and transport behaviors in optoelectronic devices. By employing pump-probe spectroscopy and ultrafast microscopy, the consequential role of e-ph coupling strength in the spatiotemporal evolution of hot electrons is elucidated. Thermal transport across the metallic interface is controlled to regulate effective e-ph coupling factor Geff in Au and Au/Cr heterostructure, and their impact on nonequilibrium transport of hot electrons is examined. Via the modulation of buried Cr thickness, a strong correlation between Geff and the diffusive behavior of hot electrons is found. By enhancing Geff through the regulation of thermal transport across interface, there is a significant reduction in e-ph thermalization time, the maximum diffusion length of hot electrons, and lattice heated area which are extracted from the spatiotemporal evolution profiles. Therefore, the increased Geff significantly weakens the diffusion of hot electrons and promotes heat relaxation of electron subsystems in both time and space. These insights propose a robust framework for spatiotemporal investigations of G impact on hot electron diffusion, underscoring its significance in the rational design of advanced optoelectronic devices with high efficiency.

Thermal Emission Manipulation Enabled by Nano-Kirigami Structures.

The nano-kirigami metasurfaces have controllable 3D geometric parameters and dynamic transformation functions and therefore provide a strong spectral regulation capability of thermal emission. Here, the authors propose and demonstrate a dynamic and multifunctional thermal emitter based on deformable nano-kirigami structures, which can be actuated by electronic bias or mechanical compression. Selective emittance and the variation of radiation intensity/wavelength are achieved by adjusting the geometric shape and the transformation of the structures. Particularly, a thermal management device based on a composite structure of nano-kirigami and polydimethylsiloxane (PDMS) thin film is developed, which can dynamically switch the state of cooling and heating by simply pressing the device. The proposed thermal emitter designs with strong regulation capability and multiple dynamic adjustment strategies are desirable for energy and sensing applications and inspire further development of infrared emitters.

Artificial Propeller Chirality and Counterintuitive Reversal of Circular Dichroism in Twisted Meta-molecules.

Here we demonstrate an optical propeller chirality in artificially twisted meta-molecules, which is remarkably different from conventional optical helical chirality. Giant circular dichroism (CD) is realized in a single layer of meta-molecule array by utilizing the surface lattice resonances that are formed by the coupling of chiral electric quadrupole modes to the diffractive lattice mode. Due to the special twist of the propeller blades, the periodic meta-molecule array is hybridized by unit cells with two different chiral centers. As a result, the CD response is readily reversed by tailoring the interference phase through engineering the structural blades without inverting the geometric chirality. Importantly, the enhanced CD and its sign reversal are demonstrated in experiments by using a nano-kirigami fabrication technique.

Reprogrammable optical metasurfaces by electromechanical reconfiguration.

Metasurfaces, with artificially designed ultrathin and compact optical elements, enable versatile manipulation of the amplitude, phase, and polarization of light waves. While most of the metasurfaces are static and passive, here we propose a reprogrammable metasurface based on the state-of-art electromechanical nano-kirigami, which allows for independent manipulation of pixels at visible wavelengths through mechanical deformation of the nanostructures. By incorporating electrostatic forces between the top suspended gold nano-architectures and bottom silicon substrate, out-of-plane deformation of each pixel and the associated phase retardation are independently controlled by applying single voltage to variable pixels or exerting programmable voltage distribution on identical pixels. As a proof-of-concept demonstration, the metasurfaces are digitally controlled and a series of tunable metasurface holograms such as 3D dynamic display and ultrathin planar lenses are achieved at visible wavelengths. The proposed electromechanical metasurface provides a new methodology to explore versatile reconfigurable and programmable functionalities that may lead to advances in a variety of applications such as hologram, 3D displays, data storage, spatial light modulations, and information processing.

Ultra-sensitive amplitude engineering and sign reversal of circular dichroism in quasi-3D chiral nanostructures.

Circular dichroism (CD), as one of the most representative chiroptical effects, provides a simple strategy for the detection and characterization of the molecular chirality. The enhancement and sign reversal of CD are of great importance for its practical applications in chiral bio-sensing, chirality switching and optical filtering, etc. Here, we realize considerable adjustments and the sign reversal of CD in quasi-three-dimensional (quasi-3D) combined Archimedean spiral nanostructures. With special local and lattice configurations, the nanostructures have both right-handed and left-handed geometric chirality, which are designed based on the proximity effect of stencil lithography. We find that the CD response of the nanostructures becomes obvious once its height exceeds 200 nm and can be adjusted by the further increase of the height or the change of the blade spacing of the nanostructures. The CD reversal is achieved by utilizing the competition of two chiral centers when the height or blade spacing exceeds a critical value. Further analysis of the scattering power of multipole moments reveals that the CD modulation is determined by both magnetic dipole moment and electric quadrupole moment. Benefiting from the highly sensitive CD response to the height, the extreme sign reversal of CD is achieved when a sub-10-nm ultrathin medium layer is anchored on the surface of the nanostructures, which provides a promising strategy for ultra-sensitive chiral bio-sensing.

Deuterogenic Plasmonic Vortices.

The optical vortex on a chip is of extreme importance for many applications in nanoscience, and as well-known, the chiral metallic nanostructures like plasmonic vortex lenses (PVLs) can produce a spin-dependent plasmonic vortex (PV) which is governed by plasmonic spin-orbit coupling. The well-established nanophotonic theory and various experimental demonstrations all show a single PV mode in one PVL, when the excitation is fixed. Here, counterintuitively, we report the existence of the nontrivial deuterogenic PVs, besides the one predicted previously. We theoretically reveal a general spin-to-orbit coupling and experimentally demonstrate the surprising existence of multiple PVs in a single PVL even when excited by a fixed circularly polarized vortex beam. This work provides a deeper fundamental understanding of the dynamics and the near-field spin-orbit coupling in nanophotonics, which promises to flexibly manipulate the PV for emerging optical vortex-based nanotechnologies and quantum optical applications on a chip.

Vector beams in planar photonic crystal cavities with rotating air holes.

We report a method to generate angularly polarized vector beams with a topological charge of one by rotating air holes to form two-dimensional photonic crystal (PC) cavities. The mode volume and resonance wavelength of these cavities are tuned from ${0.33}{(\lambda /n)^3}$0.33(λ/n)3 to ${12}{(\lambda /n)^3}$12(λ/n)3 and in a wide range of 400 nm, respectively, by controlling the range of fixed air holes near the center of the structure. As a benefit, the half-maximum divergence angles of the vector beam can be widely changed from 90° to $\sim{60}^\circ $∼60∘. By adjusting the shift direction of the air holes in the PC cavities, optical vector beams with different far-field morphology are obtained. The scheme provides not only an alternative method to generate optical vector beams, but also an effective strategy to control far-field morphology and polarizations, which holds promising applications such as optical microscopy and micro-manipulation.

Vector Exceptional Points with Strong Superchiral Fields.

Exceptional points (EPs), branch points of complex energy surfaces at which eigenvalues and eigenvectors coalesce, are ubiquitous in non-Hermitian systems. Many novel properties and applications have been proposed around the EPs. One of the important applications is to enhance the detection sensitivity. However, due to the lack of single-handed superchiral fields, all of the proposed EP-based sensing mechanisms are only useful for the nonchiral discrimination. Here, we propose theoretically and demonstrate experimentally a new type of EP, which is called a radiation vector EP, to fulfill the homogeneous superchiral fields for chiral sensing. This type of EP is realized by suitably tuning the coupling strength and radiation losses for a pair of orthogonal polarization modes in the photonic crystal slab. Based on the unique modal-coupling property at the vector EP, we demonstrate that the uniform superchiral fields can be generated with two beams of lights illuminating the photonic crystal slab from opposite directions. Thus, the designed photonic crystal slab, which supports the vector EP, can be used to perform surface-enhanced chiral detection. Our findings provide a new strategy for ultrasensitive characterization and quantification of molecular chirality, a key aspect for various bioscience and biomedicine applications.

Functional characterization of two ecto-nucleoside triphosphate diphosphohydrolase 2 genes in Japanese flounder (Paralichthys olivaceus) head kidney macrophages.

Ecto-nucleoside triphosphate diphosphohydrolases (ENTPDases) are pivotal regulators of extracellular ATP-mediated purinergic immune signaling. ENTPDase2 is a member of the cell surface-bound ecto-nucleoside triphosphate diphosphohydrolase (ENTPDase) protein family that hydrolyzes extracellular nucleoside 5'-triphosphates and nucleoside 5'-diphosphates. However, the immune relevance of ENTPDase2 in fish has not been elucidated. In the present study, from a comparative immunological perspective, we functionally characterized two ENTPDase2 transcript variants (namely ENTPDase2 and ENTPDase2a) from Japanese flounder (Paralichthys olivaceus). Sequence analysis indicates that the deduced Japanese flounder ENTPDase2 and ENTPDase2a proteins possess two conserved transmembrane domains and five apyrase conserved regions that are present in ENTPDase family proteins. However, these proteins only share 54% amino acid sequence identity. Tissue expression analysis revealed that both ENTPDase2 and ENTPDase2a mRNA transcripts are ubiquitously expressed in all examined Japanese flounder tissues, whereas ENTPDase2 is dominantly expressed in blood and ENTPDase2a is abundantly expressed in muscle. Immune challenge experiments showed that ENTPDase2 and ENTPDase2a were significantly upregulated by both inflammatory stimulation and Edwardsiella tarda infection. In addition, the expression of ENTPDase2 and ENTPDase2a was modulated by extracellular ATP (eATP) stimulation in a dose-dependent manner. Furthermore, immunolocalization and functional studies demonstrated that both ENTPDase2 and ENTPDase2a are functional glycosylated plasma membrane proteins. However, ENTPDase2a exhibits greater activity in the hydrolysis of eATP than ENTPDase2 and ENTPDase1 proteins. Finally, knockdown of the ENTPDase2 gene by small interfering RNA significantly upregulated the expression of eATP-induced proinflammatory cytokines IL-1beta, TNF-alpha and G-CSF in Japanese flounder head kidney macrophages, while knockdown of ENTPDase2a only upregulated eATP-induced IL-1beta expression. Taken together, our findings suggest that the two functional Japanese flounder ENTPDase2 isoforms play an essential role in the downregulation of eATP-induced proinflammatory cytokine expression in fish by degrading the available ATP levels in the extracellular milieu.

Lighting Silver(I) Complexes for Solution-Processed Organic Light-Emitting Diodes and Biological Applications via Thermally Activated Delayed Fluorescence.

Luminescent coinage metal complexes have shown promising applications as electroluminescent emitters, photocatalysts/photosensitizers, and bioimaging/theranostic agents, rendering them attractive alternatives to transition metal complexes based on iridium, ruthenium, and platinum that have extremely low earth abundance. In comparison to the widely studied Au(I) and Cu(I) complexes, Ag(I) complexes have seldom been explored in this field because of their inferior emission properties. Herein, we report a novel series of [Ag(N^N)(P^P)]PF6 complexes exhibiting highly efficient thermally activated delayed fluorescence by using easily accessible neutral diamine ligands and commercially available ancillary diphosphine chelates. The photoluminescence quantum yields (PLQYs) of the Ag(I) emitters are ≤0.62 in doped films. The high PLQY with a large delayed fluorescence ratio enabled the fabrication of solution-processed organic light-emitting diodes (OLEDs) with a high maximum external quantum efficiency of 8.76%, among the highest values for Ag(I) emitter-based OLEDs. With superior emission properties and an excited state lifetime in the microsecond regime, together with its potent cytotoxicity, the selected Ag(I) complex has been used for simultaneous cell imaging and anticancer treatment in human liver carcinoma HepG2 cells, revealing the potential of luminescent Ag(I) complexes for biological applications such as theranostics.

Functional characterization of purinergic receptor P2Y14 in the Japanese flounder (Paralichthys olivaceus) head kidney macrophages.

Extracellular nucleotides and nucleotide sugars are important danger-associated signaling molecules that play critical roles in regulation of immune responses in mammals through activation of purinergic receptors located on the cell surface. However, the immunological role of extracellular UDP-glucose-activated P2Y14 receptor (P2Y14R) in fish still remains unknown. In this study, we identified and characterized a P2Y14R paralog in the Japanese flounder (Paralichthys olivaceus). The mRNA transcripts of P2Y14R are detected in all examined Japanese flounder tissues. Compared with the UDP-activated P2Y6 receptor, however, P2Y14R gene is highly expressed in Japanese flounder head kidney macrophages (HKMs). In addition, P2Y14R is significantly upregulated following inflammatory stimulation with LPS and poly (I:C) in the HKMs, suggesting a role of P2Y14R in response to inflammation in fish. Furthermore, activation of P2Y14 receptor with its potent and selective agonist MRS 2905 resulted in a decreased expression of LPS-induced pro-inflammatory cytokine IL-1beta gene in the HKMs. In contrast, inhibition of P2Y14 receptor activity or down-regulation of the endogenous expression of P2Y14R by small interfering RNA significantly upregulates the LPS-induced pro-inflammatory cytokine IL-1beta gene expression in the HKMs, demonstrating that P2Y14R is involved in inflammation regulation in fish. Moreover, stimulation of the Japanese flounder HKMs with UDP-glucose evoked a rapid increase of extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation in a dose- and time-dependent manner, indicating the involvement of P2Y14R in activation of ERK1/2 signaling in fish immune cells. Taken together, we demonstrated that the inducible P2Y14R plays an important role in regulation of fish innate immunity.

Characterization of the responses of the caspase 2, 3, 6 and 8 genes to immune challenges and extracellular ATP stimulation in the Japanese flounder (Paralichthys olivaceus).

BACKGROUND: Caspases are a family of conserved intracellular cysteine-dependent aspartate-specific cysteine proteases that play important roles in regulating cell death and inflammation. Our previous study revealed the importance of the inflammatory caspase 1 gene in extracellular ATP-mediated immune signaling in Japanese flounder, Paralichthys olivaceus. To explore the potential roles of other caspases in P. olivaceus innate immunity, we extended our study by characterizing of the responses of four additional P. olivaceus caspase genes, termed JfCaspase 2, 3, 6 and 8, to inflammatory challenge and extracellular ATP stimulation. RESULTS: Sequence analysis revealed that the domain structures of all the Japanese flounder caspase proteins are evolutionarily conserved. Quantitative real-time PCR analysis showed that the JfCaspase 2, 3, 6 and 8 genes were expressed ubiquitously but at unequal levels in all examined Japanese flounder normal tissues. In addition, the basal gene expression levels of JfCaspase 2, 3, 6 and 8 were higher than those of JfCaspase 1 in both Japanese flounder head kidney macrophages (HKMs) and peripheral blood leukocytes (PBLs). Furthermore, immune challenge experiments showed that the inflammatory stimuli LPS and poly(I:C) significantly modulated the expression of the JfCaspase 2, 3, 6 and 8 genes in Japanese flounder immune cells. Finally, DNA fragmentation, associated with increased extracellular ATP-induced JfCaspase 2, 3, 6 and 8 gene expression and enzymatic activity, was inhibited by the caspase inhibitor Z-VAD-FMK in the HKMs. CONCLUSION: Our findings demonstrate broad participation of multiple caspase genes in response to inflammatory stimulation in Japanese flounder immune cells and provide new evidence for the involvement of caspase(s) in extracellular ATP-induced apoptosis in fish.

Functional characterization of purinergic P2Y2 and P2Y12 receptors involved in Japanese flounder (Paralichthys olivaceus) innate immune responses.

G-protein-coupled P2Y receptors activated by extracellular nucleotides play important roles under different physiological and pathophysiological conditions in mammals. To investigate the immunological relevance of P2Y receptors in fish, we identified and characterized the P2Y2 and P2Y12 receptors in Japanese flounder Paralichthys olivaceus. The P. olivaceus P2Y2 and P2Y12 receptors harbor seven transmembrane domains but share only 24% sequence identity. Real-time PCR analysis revealed the constitutive but unequal mRNA expression pattern of P2Y2R and P2Y12R in normal Japanese flounder tissues with the dominant expression of P2Y2R in head kidney and blood and P2Y12R in hepatopancreas. In addition, the expression of P2Y2 and P2Y12 receptors was markedly modulated by PAMPs stimulation and Edwardsiella tarda infection. Furthermore, blockage of P2Y12R potently increased ADP-activated pro-inflammatory cytokine IL-1beta gene expression in the head kidney macrophages (HKMs). Moreover, inhibition of P2Y2 and P2Y12 receptor activity with their respective potent antagonists significantly altered some of the LPS-induced pro-inflammatory cytokine gene expression in the HKMs. However, blockade of P2Y12R did not affect the poly(I:C)-induced pro-inflammatory cytokine gene expression examined in the HKMs. Collectively, we have for the first time reported the role of purinergic P2Y2 and P2Y12 receptors in fish innate immunity. Our findings have also addressed the importance of extracellular ATP and its metabolites in fish innate immune responses.

Expression analysis of Pannexin1 channel gene in response to immune challenges and its role in infection-induced ATP release in tilapia (Oreochromis niloticus).

ATP released from immune cells plays an important role in activation of host innate immunity. However, the molecular mechanisms for pathogen infection-induced ATP release in fish remains unclear. Pannexin1 (Panx1) is a recently identified ATP release channel important for controlling immune responses. The immune relevance of Panx1 in fish, however, is still poorly understood. In this study, we characterized a Panx1 gene homologue (termed tPanx1) from Nile tilapia (Oreochromis niloticus) and analyzed its expression in response to different immune challenges. We also investigated the role of tPanx1 channel in bacterial infection-induced ATP release. Real-time quantitative PCR analysis revealed that tPanx1 gene is expressed in all tested tissues with predominant expression in intestine. Immune challenges with lipopolysaccharide, polyinosinic-polycytidylic acid and zymosan led to increased gene expression of tPanx1 in tilapia head kidney cells and peripheral blood leucocytes. In addition, tPanx1 gene was up-regulated in hepatopancreas, muscle, spleen, gill, head kidney and blood after Aeromonas hydrophila infection. Furthermore, pharmacological inhibition of tPanx1 channel activity with Panx1 channel inhibitor, carbenoxolone, significantly attenuated A. hydrophila infection-induced ATP release in tilapia head kidney cells. Taken together, our findings suggested that tPanx1 is an important immune response gene involved in bacterial infection-induced ATP release in tilapia O. niloticus.

Characterization of UDP-Activated Purinergic Receptor P2Y6 Involved in Japanese Flounder Paralichthys olivaceus Innate Immunity.

Uridine 5'-diphosphate (UDP)-activated purinergic receptor P2Y6 is a member of a G-protein-coupled purinergic receptor family that plays an important role in mammalian innate immunity. However, the role of the P2Y6 receptor (P2Y6R) in fish immunity has not been investigated. In this report, we characterized a P2Y6R gene from Japanese flounder (Paralichthys olivaceus) and examined its role in fish innate immunity. Sequence analysis reveals that the Japanese flounder P2Y6R protein is conserved and possesses four potential glycosylation sites. Quantitative real-time RT-PCR analysis shows that P2Y6R is broadly distributed in all examined Japanese flounder tissues with dominant expression in the liver. In addition, P2Y6R gene expression was up-regulated in head kidney macrophages (HKMs) upon lipopolysaccharides (LPS) and poly(I:C) stimulations but down-regulated by LPS challenge in peripheral blood leukocytes (PBLs). Furthermore, pharmacological inhibition of the endogenous P2Y6 receptor activity by the potently selective P2Y6R antagonist, MRS 2578, greatly up-regulated pro-inflammatory cytokine interleukin (IL)-1ß, IL-6 and TNF-α gene expression in PBL cells treated with UDP. Moreover, LPS- and poly(I:C)-induced gene expression of IL-1ß and TNF-α in Japanese flounder PBL cells was attenuated significantly by inhibition of P2Y6R activity with antagonist MRS 2578. Collectively, we, for the first time, showed the involvement of functional purinergic P2Y6R in fish innate immunity.

Comparative analysis of dual specificity protein phosphatase genes 1, 2 and 5 in response to immune challenges in Japanese flounder Paralichthys olivaceus.

Dual-specificity MAP kinase (MAPK) phosphatases (DUSPs) are well-established negative modulators in regulating MAPK signaling in mammalian cells and tissues. Our previous studies have shown the involvement of DUSP6 in regulating innate immunity in Japanese flounder Paralichthys olivaceus. In order to gain a better understanding of the role of DUSPs in fish innate immunity, in the present study we identified and characterized three additional DUSP genes including DUSP1, 2 and 5 in P. olivaceus. The three Japanese flounder DUSP proteins share common domain structures composed of a conserved N-terminal Rhodanase/CDC25 domain and a C-terminal catalytic phosphatase domain, while they show only less than 26% sequence identities, indicating that they may have different substrate selectivity. In addition, mRNA transcripts of all the three DUSP genes are detected in all examined Japanese flounder tissues; however, DUSP1 is dominantly expressed in spleen while DUSP2 and 5 are primarily expressed in skin. Furthermore, all the three DUSP genes are constitutively expressed in the Japanese flounder head kidney macrophages (HKMs) and peripheral blood leucocytes (PBLs) with unequal distribution patterns. Moreover, all the three DUSPs gene expression was induced differently in response to the LPS and double-stranded RNA mimic poly(I:C) stimulations both in the Japanese flounder HKMs and PBLs, suggesting an association of DUSPs with TLR signaling in fish. Taken together, the co-expression of various DUSPs members together with their different responses to the immune challenges indicate that the DUSP members may operate coordinately in regulating the MAPK-dependent immune responses in the Japanese flounder.

Characterization of Japanese flounder (Paralichthys olivaceus) Caspase1 involved in extracellular ATP-mediated immune signaling in fish.

Caspase1 is a member of inflammatory Caspases that play important roles in the innate immune system. Although several teleost caspase1 genes have been identified, their partner proteins and implication in extracellular ATP-mediated immune signaling in fish are still very limited. Here we identified and characterized a caspase1 gene, named JfCaspase1, from Japanese flounder Paralichthys olivaceus. JfCaspase1 mRNA was constitutively expressed in all examined normal tissues with high expression in skin and gills and moderate expression in the enriched Japanese flounder head kidney macrophages (HKMs) and peripheral blood leukocytes (PBLs). JfCaspase1 was initially down-regulated but significantly up-regulated at the later stage upon LPS and poly(I:C) challenges in the HKMs. JfCaspase1 was also up-regulated in the Japanese flounder immune-related tissues including head kidney, gill and spleen by bacterial challenge with Edwardsiella tarda. JfCaspase1 protein is comprised of 384 amino acid residues with a calculated molecular mass of 43.75 kDa and is phylogenetically close to fish Caspase1 proteins. JfCaspase1 was co-immunopercipitated with Japanese flounder apoptosis-associated speck-like protein (ASC) when co-expressed in HeLa cells, suggesting that there is a potential interaction between the two proteins. In addition, we showed that extracellular ATP, a potent signaling molecule in activating innate immune response, rapidly up-regulates JfCaspase1 expression and enhances its enzymatic activity both in the HKMs and PBLs. Our findings indicated that the inflammatory JfCaspase1 interacted with ASC protein is implicated in the extracellular ATP-mediated immune signaling in fish.

Identification and functional analysis of dual-specificity MAP kinase phosphatase 6 gene (dusp6) in response to immune challenges in Japanese flounder Paralichthys olivaceus.

Dual-specificity phosphatase 6 (Dusp6) is a member of mitogen-activated protein kinase (MAPK) phosphatases that play crucial roles in regulating MAPK signaling and immune response. The immunological relevance of Dusp6 in fish, however, remains largely uncharacterized. In the present study, a full-length Japanese flounder dusp6 cDNA ortholog, termed PoDusp6, was identified and characterized from Paralichthys olivaceus. The deduced PoDusp6 protein is comprised of 383 amino acids with a conserved N-terminal regulatory rhodanese homology domain and a C-terminal catalytic domain. Immunofluorescence microscopy revealed that PoDusp6 protein is mainly localized in cytoplasm. Sequence analysis indicates that PoDusp6 is highly conserved (>70% identity) throughout the evolution from teleost to mammals. In unstimulated conditions, PoDusp6 mRNA was present in all examined tissues and showed the highest expression in Japanese flounder head kidney macrophages (HKMs). Immune challenge experiments revealed that the expression of PoDusp6 was down-regulated at the early stage after LPS and poly(I:C) stimulations but significantly up-regulated at the later stage in the HKMs. The similar expression pattern was also observed in the Japanese flounder immune-related tissues including head kidney, gill and spleen upon bacterial challenge with Edwardsiella tarda. Overexpression of PoDusp6 in Japanese flounder FG-9307 cells led to a significant down-regulation of proinflammatory cytokine genes IL-1beta, TNF-alpha and IFN-gamma, and antiviral gene Mx. Interestingly, inhibition of Dusp6 activity also down-regulated the LPS-induced IL-beta gene expression but did not affected on the LPS-induced IFN-gamma and TNF-alpha expression in the HKMs. Our findings suggest that the expression of PoDusp6 is modulated by immune stimuli and PoDusp6 may act as an essential modulator in fish inflammatory response.

Direct laser writing of pyramidal plasmonic structures with apertures and asymmetric gratings towards efficient subwavelength light focusing.

Efficient confining of photons into subwavelength scale is of great importance in both fundamental researches and engineering applications, of which one major challenge lies in the lack of effective and reliable on-chip nanofabrication techniques. Here we demonstrate the efficient subwavelength light focusing with carefully engineered pyramidal structures fabricated by direct laser writing and surface metallization. The important effects of the geometry and symmetry are investigated. Apertures with various sizes are flexibly introduced at the apex of the pyramids, the focusing spot size and center-to-sidelobe ratio of which could be improved a factor of ~4 and ~3, respectively, compared with the conical counterparts of identical size. Moreover, two pairs of asymmetric through-nanogratings are conceptually introduced onto the top end of the pyramids, showing significantly improved focusing characteristics. The studies provide a novel methodology for the design and realization of 3D plasmonic focusing with low-noise background and high energy transfer.

Giant enhancement of second harmonic generation by engineering double plasmonic resonances at nanoscale.

We have investigated second harmonic generation (SHG) from Ag-coated LiNbO3(LN) core-shell nanocuboids and found that giant SHG can occur via deliberately designed double plasmonic resonances. By controlling the aspect ratio, we can tune fundamental wave (FW) and SHG signal to match the longitudinal and transverse plasmonic modes simultaneously, and achieve giant enhancement of SHG by 3 × 10(5) in comparison to a bare LN nanocuboid and by about one order of magnitude to the case adopting only single plasmonic resonance. The underlying key physics is that the double-resonance nanoparticle enables greatly enhanced trapping and harvesting of incident FW energy, efficient internal transfer of optical energy from FW to the SHG signal, and much improved power to transport the SHG energy from the nanoparticle to the far-field region. The proposed double-resonance nanostructure can serve as an efficient subwavelength coherent light source through SHG and enable flexible engineering of light-matter interaction at nanoscale.