Fast NO Research Articles

Nitric oxide-releasing thiolated starch nanoparticles embedded in gelatin sponges for wound dressing applications

This study introduces a novel wound dressing by combining nitric oxide-releasing thiolated starch nanoparticles (NO-TS NPs) with gelatin. First, starch was thiolated (TS), and then its nanoparticles were prepared (TS NPs). Subsequently, NPs were covalently bonded to sodium nitrite to obtain NO-releasing TS NPs (NO-TS-NPs) that were incorporated into gelatin sponges at various concentrations. The resulting spherical TS NPs had a mean size of 85.42 ± 5.23 nm, which rose to 100.73 ± 7.41 nm after bonding with sodium nitrite. FTIR spectroscopy confirmed S-nitrosation on the NO-TS NPs' surface, and morphology analysis showed well-interconnected pores in all sponges. With higher NO-TS NPs content, pore size, porosity, and water uptake increased, while compressive modulus and strength decreased. Composites exhibited antibacterial activity, particularly against E. coli, with enhanced efficacy at higher NPs' concentrations. In vitro release studies demonstrated Fickian diffusion, with faster NO release in sponges containing more NPs. The released NO amounts were non-toxic to fibroblasts, but samples with fewer NO-TS NPs exhibited superior cellular density, cell attachment, and collagen secretion. Considering the results, including favorable mechanical strength, release behavior, antibacterial and cellular properties, gelatin sponges loaded with 2 mg/mL of NO-TS NPs can be suitable for wound dressing applications.

Synergistic Effect of Cu/CeO2 and Pt-BaO/CeO2 Catalysts for a Low-Temperature Lean NO x Trap.

A lean NO x trap (LNT) catalyst has been widely used for removing NO x exhaust from lean-burn engines. However, the operation range of LNT has been limited because of the poor activity of LNT catalysts at low temperatures (≤300 °C), especially in urban driving conditions. To increase NO x removal efficiency during lean-rich cycle operation, a Cu/CeO2 (CC) catalyst was added to a Pt-BaO/CeO2 (PBC) catalyst. In comparison to PBC- or CC-only catalysts, the physical mixture of PBC and CC catalysts (PBC + CC) exhibited a significant synergy for both NO x storage and reduction efficiencies. In particular, low-temperature activity below 200 °C was greatly enhanced. A Pt-BaO-Cu/CeO2 (PBCC) catalyst, which was synthesized by depositing Pt and Cu together on a ceria support, showed poorer NO x removal efficiency. The origin of the synergistic effect over PBC + CC was investigated. Under lean conditions, the CC showed much better activity for NO oxidation, allowing for faster NO x storage on PBC. Under rich conditions, H2 was generated in situ on the CC by a water-gas shift reaction then accelerated the reduction of NO x, which had been stored on PBC, with a higher selectivity to N2. This simple modification in the catalyst can provide an important clue to enhance low-temperature activity of the commercial LNT system.

Instantaneous NO release from ellipsoidal particles during char combustion in a hot gas with fluctuating temperature

We have established the instantaneous governing equations for NO release during char combustion of nonspherical particles theoretically. The instantaneous released NO mass variations, the instantaneous char oxidation reaction rates, and the instantaneous NO reduction reaction rates of char particles were computed numerically under different fluctuation amplitudes of gas temperature, kinetic parameters of char oxidation reaction and NO reduction reaction, and particle aspect ratios. The gas temperature fluctuation results in a faster NO release rate, a faster char oxidation reaction rate, and a faster NO reduction reaction rate during the whole char combustion processes. The activation energy of char oxidation reaction has obvious influence on the NO release and char combustion processes. The kinetic parameters of NO reduction reaction have no contribution to the conversion time. Under the same particle surface area, the conversion rate of char nitrogen to NO increases with the increase in the particle aspect ratio.

Nitric oxide release by N-(2-chloroethyl)-N-nitrosoureas: a rarely discussed mechanistic path towards their anticancer activity

Our work shows that NO release is a feasible pathway of action for aromatic and heterocyclic N-(2-chloroethyl)-N-nitrosoureas and faster NO release may not lead to higher cytotoxicity.

PSS222 - Mechanism of Faster NO Scavenging by Older Stored Red Blood Cells

PSS222 - Mechanism of Faster NO Scavenging by Older Stored Red Blood Cells

Effects of gas temperature fluctuation on the NO release from pulverized coal particle during char combustion

The effects of gas temperature fluctuation on the NO release from pulverized coal particle during char combustion are investigated. The computed results show that the NO formation through the heterogeneous oxidation and reduction reactions is influenced by the gas temperature fluctuation for the particles with initial diameters of 10–50 μm. The gas temperature fluctuation leads to faster NO release from the particle. The heterogeneous NO formation during the char combustion is further enhanced by the increase in the fluctuation amplitude of gas temperature.

Nitrogen cycling across the sediment-water interface in an eutrophic, artificially oxygenated lake

Processes controlling the nitrogen (N) exchange between water and sediment in eutrophic Lake Sempach were studied using three different independent methods: benthic flux chambers, interstitial water data and hypolimnetic mass balances. The sediments released NH 4 + (1.1–16.1 mmoles m−2 d−1), NO 2 - (0.1–0.4 mmoles m−2 d−1) and dissolved organic N (<0.25 mmoles m−2 d−1). A net NO 3 - consumption (2.4–11.1 mmoles m−2 d−1) related to the NO 3 - concentrations in the overlying water was observed in all benthic chamber experiments. The flux of the reactive species NO 3 - and NH 4 + was found to depend on hydrodynamic conditions in the water overlying the sediment. For this reason, benthic chambers overestimated the fluxes of inorganic N compared to the other methods. Thus, in short-term flux chamber experiments the sediment may either become a sink or a source for inorganic N depending on the O2 concentration in the water overlying the sediment and the stirring rate. As demonstrated with a15NO 3 - experiment, nitrate-ammonification accounted for less than 12% of the total NO 3 - consumption. After six years of artificial oxygenation in Lake Sempach, a decrease in hypolimnetic total inorganic nitrogen (TIN) was observed in the last two years. The occurrence of dense mats of H2S-oxidizingBeggiatoa sp. indicated micro-aerobic conditions at the sediment surface. Under these conditions, a shorter distance between the ecological niches of nitrifying and denitrifying bacteria, and therefore a faster NO 3 - -transport, can possibly explain the lowering of TIN by enhanced net denitrification.