Microscopic Investigation of Reversible Nanoscale Surface Size Dependent Protein Conjugation

Aβ1–40 coated 20 nm gold colloidal nanoparticles exhibit a reversible color change as pH is externally altered between pH 4 and 10. This reversible process may contain important information on the initial reversible step reported for the fibrillogenesis of Aβ (a hallmark of Alzheimer’s disease). We examined this reversible color change by microscopic investigations. AFM images on graphite surfaces revealed the morphology of Aβ aggregates with gold colloids. TEM images clearly demonstrate the correspondence between spectroscopic features and conformational changes of the gold colloid

Support-Free Bimodal Distribution of Plasmonically Active Ag/AgO_<i>x</i> Nanoparticle Catalysts: Attributes and Plasmon Enhanced Surface Chemistry

A self-regenerative metal/metal oxide nanostructure comprised of a bimodal distribution (e.g., 6 and 160 nm average diameters) of silver (Ag) nanoparticles (NPs) with a AgO_<i>x</i> surrounding is introduced as a new type of plasmonic catalyst through a physical method used in this work. The support-free catalyst shows plentiful surface adsorbed oxygen species along with excellent localized surface plasmon resonance (LSPR) and appreciable photoluminescence (PL). These properties plus the structural features enable highly active catalysis toward reactions of H₂, O₂, CO, and hydrocarbons at ambient to elevated operating temperatures without any deactivation observed over ∼150 h thermal cycles (at 350 °C) of catalytic reaction tests. Over this highly active catalyst, plasmon induced preferential growth of surface oxygen species and surface reactions are demonstrated via <i>in situ</i> Raman spectroscopy. These studies suggest that the enhanced surface species growth and catalytic process result from surface transfer of hot electrons generated by interband transitions with plasmon enhanced local field and intraband transitions with plasmon nonradiative decay. The revealed coupling of energetic plasmons with surface species formation and reactivity can be used to guide rational design of catalysts and processes. The combination of high activity and durability of this plasmonic catalyst makes it viable for potential energy and cost-effective catalytic applications

Gold nanoparticles encapsulated in a soda-lime glass substrate for plasmonic temperature sensing

We present a study on the temperature response of the plasmon peak of gold nanoparticles (AuNPs) completely encapsulated in soda-lime glass for temperatures ranging from 298 K to 723 K and in ambient pressure air, Ar and aqueous environments. The observed peak position changed with temperature in a linear manner, as expected from the theoretical model also presented in this study. The linear character was upheld in different gaseous environments of inert Ar and ambient air, as well as in both pure deionized water and acidic water. The consistent expected dependence provided proof of the versatility of the encapsulated AuNPs and their robustness to be able to withstand both high temperature and high acidity and still retain their sensing capability. Keywords: Localized surface plasmon resonance, Au nanoparticle, Pure temperature sensing, Fully encapsulatio

Effects of tributyltin at environmental levels on monooxygenase system of digestive gland in hard clam Meretrix meretrix

The effects on ethoxyresorufin O-deethylase (EROD), NADPH-cytochrome c reductase and NADH cytochrome b5 reductase activities of digestive gland in Meretrix meretrix exposed to tributyltin (TBT) at environmental levels (0.1, 1.0, 10.0 ng/dm(3) as stannum concentration), in experimental condition, were evaluated. The EROD, NADH cytochrome b5 reductase activities were significantly inhibited after exposure to 10.0 ng/dm(3) TBT for 8 and 20 d, the NADPH cytochrome c reductase activities were significantly inhibited after exposure to 0.1, 1.0 and 10.0 ng/dm(3) TBT for 8 d and to 1.0 and 10.0 ng/dm(3) for 20 d, as compared with the matched control, while NADH cytochrome b5 reductases and NADPH cytochrome c reductase activities were induced after exposure to 10. 0 ng/dm(3) TBT for 2 d. The EROD activity in the 10 ng/dm(3) group, and the NADH cytochrome b5 reductases activities in 1.0 and 10.0 ng/dm(3) groups, were significantly induced when transfer-red to clean recovery tanks for 7 d. The three enzymic activities in the clams exposed to TBT were recovered to the level corresponding to that of the control group after transfer to clean recovery tanks for 20 d. NADPH cytochrome c reductase activity in Meretrix meretrix seems to be more sensitive to exposure of TBT than that of the EROD and NADH cytochrome b5 reductases. The results suggest that induction and inhibition by TBT to the monooxygenase system enzymic activity in Meretrix meretrix would simultaneously exist. The enzymic activities were inhibited by exposure for a long time. The results suggest that inhibition of the monooxygenase system should be an indication of the exposure to environmentally relevant concentrations of TBT for a long time

Outcomes of Technical Variant Liver Transplantation versus Whole Liver Transplantation for Pediatric Patients: A Meta-Analysis

<div><p>Objective</p><p>To overcome the shortage of appropriate-sized whole liver grafts for children, technical variant liver transplantation has been practiced for decades. We perform a meta-analysis to compare the survival rates and incidence of surgical complications between pediatric whole liver transplantation and technical variant liver transplantation.</p><p>Methods</p><p>To identify relevant studies up to January 2014, we searched PubMed/Medline, Embase, and Cochrane library databases. The primary outcomes measured were patient and graft survival rates, and the secondary outcomes were the incidence of surgical complications. The outcomes were pooled using a fixed-effects model or random-effects model.</p><p>Results</p><p>The one-year, three-year, five-year patient survival rates and one-year, three-year graft survival rates were significantly higher in whole liver transplantation than technical variant liver transplantation (OR = 1.62, 1.90, 1.65, 1.78, and 1.62, respectively, <i>p</i><0.05). There was no significant difference in five-year graft survival rate between the two groups (OR = 1.47, <i>p</i> = 0.10). The incidence of portal vein thrombosis and biliary complications were significantly lower in the whole liver transplantation group (OR = 0.45 and 0.42, both <i>p</i><0.05). The incidence of hepatic artery thrombosis was comparable between the two groups (OR = 1.21, <i>p</i> = 0.61).</p><p>Conclusions</p><p>Pediatric whole liver transplantation is associated with better outcomes than technical variant liver transplantation. Continuing efforts should be made to minimize surgical complications to improve the outcomes of technical variant liver transplantation.</p></div

Overall Design of Anode with Gradient Ordered Structure with Low Iridium Loading for Proton Exchange Membrane Water Electrolysis

Insufficient catalyst utilization, limited mass transport, and high ohmic resistance of the conventional membrane electrode assembly (MEA) lead to significant performance losses of proton exchange membrane water electrolysis (PEMWE). Herein we propose a novel ordered MEA based on anode with a 3D membrane/catalytic layer (CL) interface and gradient tapered arrays by the nanoimprinting method, confirmed by energy dispersive spectroscopy. Benefiting from the maximized triple-phase interface, rapid mass transport, and gradient CL by overall design, such an ordered structure with Ir loading of 0.2 mg cm–2 not only greatly increases the electrochemical active area by 4.2 times but also decreases the overpotentials of both mass transport and ohmic polarization by 13.9% and 8.7%, respectively, compared with conventional MEA with an Ir loading of 2 mg cm–2, thus ensuring a superior performance (1.801 V at 2 A cm–2) and good stability. This work provides a new strategy of designing MEA for high-performance PEMWE