Hydrophobic sponge structure‐based triboelectric nanogenerators using an inverse opal structured film for sustainable energy harvesting over a wide range of humid atmosphere have been successfully ...demonstrated. The output voltage and current density reach a record value of 130 V and 0.10 mA cm−2, respectively, giving over 10‐fold power enhancement, compared with the flat film‐based triboelectric nanogenerator.
Because of the current shortage of first-generation phosgene sensors, increased attention has been given to the development of fluorescent and colorimetric based methods for detecting this toxic ...substance. In an effort focusing on this issue, we designed the new, second-generation phosgene chemosensor 1 and demonstrated that it undergoes a ring-opening reaction with phosgene in association with color and fluorescent changes with a detection limit of 3.2 ppb. Notably, in comparison with the first-generation sensor RB-OPD, 1 not only undergoes a much faster response toward phosgene with an overall response time within 2 min, but it also generates no byproducts during the sensing process. Finally, sensor 1 embedded nanofibers were successfully fabricated and used for accurate and sensitive detection of phosgene.
We developed a colorimetric and fluorescent turn-on carbon dioxide sensor that relies on a polydiacetylene, PDA-1, functionalized with amines and imidazolium groups. The pendant amines react with CO2 ...under basic conditions to form carbamoate anions, which partially neutralize the polymer’s positive charges, inducing a phase transition. PDA-1 allows for the selective sensing of CO2 with high sensitivity, down to atmospheric concentrations. Naked-eye detection of CO2 is accomplished either in water solutions of PDA-1 or in the solid state with electrospun coatings of PDA-1 nanofibers.
The precise design and synthesis of plasmonic nanostructures allow us to manipulate, enhance, and utilize the optical characteristics of metallic materials. Although many multimeric structures (e.g., ...dimers) with interparticle nanogap have been heavily studied, the plasmonic nanostructures with a conductive junction have not been well studied mostly because of the lack of the reliable synthetic methods that can reproducibly and precisely generate a large number of the plasmonic nanostructures with a controllable conductive nanojunction. Here, we formed various asymmetric Au–Ag head–body nanosnowman structures with a highly controllable conductive nanojunction and studied their plasmon modes that cover from visible to near-infrared range, electromagnetic field enhancement, and surface-enhanced Raman scattering (SERS) properties. It was shown that change in the plasmonic neck region between Au head and Ag body nanoparticles and symmetry breaking using different sizes and compositions within a structure can readily and controllably introduce various plasmon modes and change the electromagnetic field inside and around a nanosnowman structure. The charge-transfer and capacitive coupling plasmon modes at low frequencies are tunable in the snowman structure, and subtle change in the conductive junction area of the nanosnowman dramatically affects the resulting electromagnetic field and optical signal. The relationships between the electromagnetic field distribution and enhancement in the snowman structure, excitation laser wavelength, and Raman dye were also studied, and it was found that the strongest electromagnetic field was observed in the crevice area on the junction and synthesizing a thinner and sharper neck junction is critical to generate the stronger electromagnetic field in the crevice area and to obtain the charge-transfer mode-based near-infrared signal. We have further shown that highly reproducible SERS signals can be generated from these nanosnowman structures with a linear dependence on particle concentration (5 fM to 1 pM) and the SERS-enhancement factor values of >108 can be obtained with the aid of the resonance effect in SERS. Finally, a wide range of LSPR bands with high tunability along with high structural reproducibility and high synthetic yield make the nanosnowman structures as very good candidates for practically useful multiple-wavelength-compatible, quantitative and sensitive SERS probes, and highly tunable nanoantenna structures.
Here, we report the unique transformation of one-dimensional tubular mixed oxide nanocomposites of iridium (Ir) and cobalt (Co) denoted as Ir x Co1–x O y , where x is the relative Ir atomic content ...to the overall metal content. The formation of a variety of Ir x Co1–x O y (0 ≤ x ≤ 1) crystalline tubular nanocomposites was readily achieved by electrospinning and subsequent calcination process. Structural characterization clearly confirmed that Ir x Co1–x O y polycrystalline nanocomposites had a tubular morphology consisting of Ir/IrO2 and Co3O4, where Ir, Co, and O were homogeneously distributed throughout the entire nanostructures. The facile formation of Ir x Co1–x O y nanotubes was mainly ascribed to the inclination of Co3O4 to form the nanotubes during the calcination process, which could play a critical role in providing a template of tubular structure and facilitating the formation of IrO2 by being incorporated with Ir precursors. Furthermore, the electroactivity of obtained Ir x Co1–x O y nanotubes was characterized for oxygen evolution reaction (OER) with rotating disk electrode voltammetry in 1 M NaOH aqueous solution. Among diverse Ir x Co1–x O y , Ir0.46Co0.54O y nanotubes showed the best OER activity (the least-positive onset potential, greatest current density, and low Tafel slope), which was even better than that of commercial Ir/C. The Ir0.46Co0.54O y nanotubes also exhibited a high stability in alkaline electrolyte. Expensive Ir mixed with cheap Co at an optimum ratio showed a greater OER catalytic activity than pure Ir oxide, one of the most efficient OER catalysts.
•RBIV causes systemic infections in rock bream.•Spleen reached its lethal level the fastest during RBIV infection.•Hemoglobins (α and β), CLNK and GALT were lowest expressed in RBIV-infected rock ...bream.•The RBC, HGB and HCT levels gradually decreased during RBV infection.
Rock bream iridovirus (RBIV), belonging to Megalocytivirus, causes severe mortality in rock bream. Almost all deaths associated with RBIV are accompanied by splenic enlargement and anemia. Although red blood cells (RBCs) are involved in the immune response against viral infections, their involvement in rock bream has not yet been studied in terms of the immune response against RBIV. In this study, the viral replication patterns, blood characteristics and anemia-related factors were evaluated in rock bream post RBIV infection. The virus-infected RBCs of rock bream demonstrated similarities in the expression levels of hemoglobins (HGB) (α and β), cytokine-dependent hematopoietic cell linker (CLNK) and hematopoietic transcription factor GATA (GATA), with significantly decreasing levels from 4 days post infection (dpi) to 17 (dpi), when the viral replication was at its peak. This suggests that the expression of blood-related genes is inadequate for HGB synthesis and RBC production, thereby causing anemia leading to death. Moreover, the levels of complete blood cell count (CBC) indicators, such as RBCs, HGB and hematocrit (HCT), significantly decreased from 10 to 17 dpi. This phenomenon suggests that blood-related gene expression and/or RBC-, HGB- and HCT-related levels are critical factors in RBIV-induced anemia and disease progression. These results highlight the significance of blood-mediated immune responses against RBIV infection in rock bream. Understanding blood-related gene levels to identify blood-related immune response interactions in rock bream will be useful for development of future strategies in controlling RBIV diseases in rock bream.
Production losses of olive flounder (Paralichthys olivaceus) have increased owing to viral haemorrhagic septicaemia virus (VHSV) infection. In this study, we determined safe concentrations of orally ...administered saponin and chitosan by analysing serum enzyme (AST/ALT) levels as biochemical markers of hepatic injury. Furthermore, we demonstrated the efficacy, duration of protection, and safety of saponin and chitosan-based vaccines with inactivated VHSV (IV). Oral administration of saponin, chitosan, and their combination did not induce fish mortality at all tested concentrations (0.29, 1.45, and 2.9 mg/g of fish body weight/day) 10 days after administration. However, AST level was high at a dose >0.29 mg/g of fish body weight/day. Both saponin and chitosan were found to be safe and acceptable for vaccination studies at a dose of 0.29 mg/g of fish body weight/day. Administration of IV alone did not induce protection at 2 and 4 weeks post vaccination (wpv). Olive flounders administered saponin + IV and chitosan + IV vaccines had higher immunity against VHSV with relative percentage survival (RPS) of 12.5–7.5% and 0–20.1%, respectively; however, additional immunisation with combination of saponin + chitosan + IV clearly enhanced the protection with RPS values of 10–15%, 26.7%, 42.9%, and 37.5% at 4, 8, 12, and 20 wpv, respectively. Although the RPS value of oral immunisation was not comparable to that of injectable vaccines, the manufacturing process is simple and oral administration causes less stress to juvenile fish. To investigate the development of a protective immune response, olive flounder were re-challenged with VHSV (107.8 TCID50/fish) at 70 days postinfection; 100% of the previously unexposed fish died, whereas 80–100% of the previously immunised fish survived. Our results showed the possibility of developing preventive measures against VHSV using saponin and chitosan-based oral vaccines with inactivated virus.
•Saponin and chitosan administration was not induced fish mortality.•Saponin (0.29 mg/g/day) and chitosan (0.29 mg/g/day) is effective as vaccine adjuvants.•Administration with saponin (0.29 mg/g/day) + chitosan (0.29 mg/g/day) + inactivated VHSV (5 μl/g/day) oral vaccine provided significant protection for 20 weeks.
RhCo alloy nanotubes were synthesized via the reduction of single-phase Co2RhO4 nanotubes. The reduction was conducted by thermal annealing of the Co2RhO4 nanotubes under hydrogen gas flow. The ...crystallinity of the prepared RhCo alloy nanotubes depended on the reduction temperature: amorphous phase (200 °C reduction) and the crystalline phase (300 °C reduction). The hydrogen evolution reaction (HER) on RhCo alloys was investigated with voltammetry in 1.0 M HClO4 solution. Amorphous RhCo alloys provided lower overpotential than the crystalline counterpart despite their similar morphology and composition. Of great interest, amorphous RhCo alloy nanotubes exhibited an outstanding HER electroactivity verified with a low overpotential at −10 mA cm–2 (−22 mV) and a small Tafel slope (−24.1 mV dec–1), outperforming commercial Pt, pure Rh metal, and the other previously reported Rh-based catalysts. This excellent HER activity of amorphous RhCo nanotubes was attributed to the amorphous structure having a large electrochemical surface area and maximized Rh–Co interfaces in the alloy facilitating HER. Active but expensive Rh alloyed with less active but cheap Co was successfully demonstrated as a potential cost-effective HER catalyst.
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