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In this study, the reaction kinetics for a heterogeneous oxidation reaction of elemental mercury (Hg(0)) vapor with CuCl 2 was studied in a fixed-bed reactor using 2%(wt) CuCl 2 /α-Al 2 O 3 between 100 and 180 °C for Hg(0) oxidation after air preheater at a typical coal-fired power plant. The reaction rate expression was first order with respect to Hg(0). However, between 100 and 180 °C, CuCl 2 over α-Al 2 O 3 agglomerates and sinters. This sintering effect added significant mass-transfer resistance to the diffusion of Hg(0) vapor, and thus made the conversion of CuCl 2 incomplete. Therefore, a grain model was formulated to determine the rate constant by taking into account the mass-transfer resistance. The model constituted a two parameter estimation problem for the determination of the rate constant and product layer diffusivity. The model predictions with the two optimum parameters were in good agreement with the experimental data. The activation energy value determined from the rate constant values was significantly lower than those for other Hg(0) oxidation catalysts under HCl and O 2 gases reported in the literature. This result corroborates that CuCl 2 can enhance Hg(0) oxidation by lowering the activation energy barrier with the reduction of Cu(2+) to Cu(1+) and supplying thermally stable surface Cl sites following a Mars-Maessen mechanism. CuCl 2 -based catalyst has potential to be applied after air preheater for Hg(0) oxidation followed by the separation of Hg(2+) in wet flue gas desulfurization (FGD) system or by activated carbon (AC) injection. [ABSTRACT FROM AUTHOR]

The catalytic oxidation of elemental mercury (Hg(0)) vapor is an effective way to enhance mercury removal from coal-fired power plants. RuO 2 catalyst was found to be an excellent Hg(0) oxidation catalyst. When rutile TiO 2 was used as the catalyst support, RuO 2 formed well dispersed nano-layers due to the very similar crystal structures of RuO 2 and rutile TiO 2 , giving higher Hg(0) oxidation activity over anatase TiO 2 support. The RuO 2 /rutile TiO 2 catalyst can be used at the tail end section of the selective catalytic reduction (SCR) unit for Hg(0) oxidation. It showed good Hg(0) oxidation performance under sub-bituminous and lignite coal simulated flue gas conditions with low concentration of HCl or HBr gas. The RuO 2 /rutile TiO 2 catalyst also showed excellent resistance to SO 2 under bituminous coal simulated flue gas, maintaining higher than 90% Hg(0) oxidation with up to 2,000 ppmv SO 2 present. The oxidized mercury in a form of HgCl 2 has a high solubility in water and can be easily captured by other air pollution control systems such as wet scrubbers in coal-fired power plants. [ABSTRACT FROM AUTHOR]

Based on previous experimental adsorption kinetic and equilibrium data for mercuric chloride (HgCl 2 ) adsorption onto raw activated carbon (AC), a comprehensive model was formulated for its removal in the ductwork and fabric filter by raw AC injection in coal combustion flue gas. Various factors that can impact the performance and sorbent utilization were investigated, including inlet HgCl 2 concentration, sorbent loading, particle size, external and internal mass-transfer considerations, residence time, filtration time, injection mode, and pressure drop. Despite these considerations, in-flight removal of HgCl 2 in the ductwork was found to be almost negligible. For the removal in fabric filter, the effect of particle size was found to be significant, particularly for continuous sorbent injection. On the other hand, a discontinuous injection mode delivering the same amount of sorbent in 10% of a cleaning cycle resulted in higher removal performance and sorbent utilization. However, at the end of the cleaning cycle, most of the sorbent capacity was not used (<0.2%). The pressure drop across the filter cake built by fly ash and sorbent was found to be manageable within typical operating limits. [ABSTRACT FROM AUTHOR]

[Display omitted] • Modified peroxamide-based ROS-responsive doxorubicin prodrugs were synthesized. • Among five prodrug candidates, OH-mOX-Dox showed the highest ROS-sensitive response. • OH-mOX-Dox showed selective cytotoxicity toward breast cancer cells. • OH-mOX-Dox showed significantly reduced cytotoxicity toward normal breast cells. • X-ray induced increased ROS level resulted in enhanced cytotoxicity of OH-mOX-Dox. Reactive oxygen species (ROS) plays a pivotal physiological role in intracellular signaling of any living organism. Due to the elevated levels of ROS in tumor microenvironment than normal tissues, an increasing number of ROS-responsive probes and prodrugs is being studied for the fight against cancer. This study describes the design and synthesis of a panel of novel modified peroxamide-based ROS-responsive prodrugs of doxorubicin, among which the OH-mOX-Dox prodrug showed very stable and highly specific ROS sensitivity. This novel Dox prodrug exerted potent anti-proliferation effects against the two breast cancer cell lines of MDA-MB-468 and MDA-MB-231 while it showed minimal toxicity toward the normal breast cell line, MCF-12A. The cytotoxicity of the OH-mOX-Dox prodrug was significantly enhanced at elevated ROS levels after co-incubation with l -buthionine sulfoximine (BSO). Our clonogenic assay data validated that enhanced intracellular ROS level upon X-ray irradiation resulted in an increase in the efficacy of the OH-mOX-Dox prodrug against the two breast cancer cell lines. [ABSTRACT FROM AUTHOR]

[Display omitted] • HgCl formation was assumed to be a rate-determining step over Mo-V catalyst. • A steady-state kinetic model was constructed based on elementary steps. • Kinetic and thermodynamic parameters were determined from the kinetic model. • Hg(0) oxidation was found to be limited by a combination of equilibrium and kinetics. A kinetic study of elemental mercury (Hg(0)) oxidation reaction over molybdenum (Mo)-promoted vanadium (V)-based selective catalytic reduction (SCR) catalyst was carried out. To probe the role of HCl and O 2 in Hg(0) oxidation over the catalyst, a real-time Hg(0) oxidation experiment was conducted. It was found that Hg(0) adsorption was negligible and HCl adsorbed onto the catalyst surface could show consistent Hg(0) oxidation performances in the presence of O 2 at realistic SCR temperatures. NH 3 showed competitive adsorption with HCl, resulting in degrading Hg(0) oxidation performance. X-ray Absorption Near-Edge Structure (XANES) data for mercury species showed that HgCl 2 was the major mercury species formed onto the spent catalyst under typical flue gas conditions. Based on the current and previous studies, an Eley-Rideal followed by Langmuir-Hinshelwood mechanism was proposed, comprising multiple elementary reaction steps. A steady-state kinetic study was conducted based on an assumption of HgCl formation as a rate-determining step. The kinetic and thermodynamic parameters determined from this study shed light on fundamental insights and practical catalytic reactor designs. [ABSTRACT FROM AUTHOR]

[Display omitted] • NPs successfully achieved sequential delivery of miR-21 inhibitor followed by Dox. • NPs delivered miR-21 inhibitor to the cytoplasm through endosomal escape. • NPs downregulated miR-21 levels and upregulated PTEN levels. • NPs showed enhanced cytotoxicity against MDA-MB-231 and A549 cells. Targeted combination therapy has shown promise to achieve maximum therapeutic efficacy by overcoming drug resistance. MicroRNA-21 (miR-21) is frequently overexpressed in various cancer types including breast and non-small cell lung cancer and its functions can be inhibited by miR inhibitor (miR-21i). A combination of miR-21i and a chemo drug, doxorubicin (Dox), can provide synergistic effects. Here, we developed a calcium phosphate (CaP)-coated nanoparticle (NP) formulation to co-deliver miR-21i along with Dox. This NP design can be used to deliver the two agents with different physiochemical properties. The NP formulation was optimized for particle size, polydispersity, Dox loading, and miR-21i loading. The NP formulation was confirmed to downregulate miR-21 levels and upregulate tumor suppressor gene levels. The cytotoxic efficacy of the combined miR-21i and Dox-containing NPs was found to be higher than that of Dox. Therefore, the CaP-coated hybrid lipid-polymeric NPs hold potential for the delivery of miR-21i and Dox. [ABSTRACT FROM AUTHOR]

[Display omitted] • Sequentially prepared Mo-V-based SCR catalyst showed excellent dual performances. • Anatase TiO 2 and calcination temperatures 400/500 °C showed the best performance. • Calcination temperature 700 °C led to TiO 2 phase transition and agglomeration. • Rutile TiO 2 or higher calcination temperature decreased V(5+) content. • Hg0 oxidation efficiency could achieve >99% at 5,000 hr−1 space velocity. Molybdenum (Mo)-vanadium (V)-based selective catalytic reduction (SCR) catalyst synthesized by the sequential impregnation of Mo and W followed by V was investigated for simultaneous elemental mercury (Hg0) oxidation and nitrogen oxide (NO) reduction in an existing SCR unit with respect to different TiO 2 phases, calcination temperatures, flue gas constituents, gas velocities, and reaction temperatures. Anatase phase TiO 2 and the calcination temperatures of 400 and 500 °C resulted in ∼69% Hg0 oxidation at 10 ppmv HCl and 350 °C. The high calcination temperature of 700 °C resulted in TiO 2 phase transformation from anatase to rutile and agglomeration. The modified SCR catalyst prepared with the impregnation sequence of Mo and W followed by V using anatase TiO 2 and calcination temperature 500 °C showed ∼99% Hg0 oxidation and 87% NO reduction conversions at an NH 3 /NO molar ratio of 0.9 under 350 °C and 5,000 hr−1 space velocity in typical sub-bituminous and lignite coal simulated flue gases. The effects of these parameters and conditions were further investigated using various characterization techniques including BET, TEM, XRD, NH 3 TPD and XAFS. [ABSTRACT FROM AUTHOR]

• Fucoidan-conjugated doxorubicin nanoparticles were developed to target P-selectin. • Nanoparticles showed uniform sizes, stability, and pH responsiveness. • DSPE-PEG helped control and stabilize the size and stability of nanoparticles. • NPs showed enhanced cellular uptake in cell line with high P-selectin expression. • NPs showed enhanced cytotoxicity against cell line with high P-selectin expression. Fucoidan, a type of sulfated polysaccharide known for its anticoagulant, anti-tumor and anti-inflammatory effects, has been reported to have strong affinity towards P-selectin. P-selectin, which plays an important role in metastasis by enhancing the adhesion of cancer cells to endothelium and activated platelets in distant organs, is overexpressed on many cancer types. This study demonstrates the synthesis of a fucoidan-based drug delivery system for minimizing the side effects of doxorubicin (Dox) with the help of active targeting toward P-selectin. Fucoidan-doxorubicin nanoparticles (FU-Dox NPs), developed by direct conjugation of Dox to the fucoidan backbone, showed a well-controlled size distribution and sustained release. The active targeting capability of FU-Dox NPs toward P-selectin resulted in enhanced cellular uptake and cytotoxicity against the MDA-MB-231 cell line with high P-selectin expression compared to the MDA-MB-468 cell line with low P-selectin expression. [ABSTRACT FROM AUTHOR]

Linear combination fitting of the X-ray Absorption Near Edge Spectroscopy (XANES) was used to quantify oxidized mercury species over RuO 2 /TiO 2 and Selective Catalytic Reduction (SCR) catalysts under different simulated flue gas conditions. Halogen gases play a major role in mercury oxidation. In the absence of halogen gas, elemental mercury can react with sulfur that is contained in both the RuO 2 /TiO 2 and SCR catalysts to form HgS and HgSO 4 . In the presence of HCl or HBr gas, HgCl 2 or HgBr 2 is the main oxidized mercury species. When both HCl and HBr gases are present, HgBr 2 is the preferred oxidation product and no HgCl 2 can be found. The formation of HgO and HgS cannot be neglected with or without halogen gas. Other simulated flue gas components such as NO, NH 3 , SO 2 and CO 2 do not have significant effect on oxidized mercury speciation when halogen gas is present. [ABSTRACT FROM AUTHOR]

There is an increasing interest in engineered nanoparticle (NP) conjugates for targeted and controlled drug delivery. However, the practical applications of these NP delivery vehicles remain constrained because of their reactivity with the body’s immune system defenses resulting in undesirable off-target effects. In this study, poly(D,L lactide-co-glycolide) (PLGA)- b -polyethylene glycol (PEG) NPs conjugated to different quantities of the commercial antibody Herceptin ® meant to target HER2-positive breast cancer cells were studied for their immune cell uptake and immunogenic properties (using murine macrophages and human dendritic cells). We further modified the Herceptin ® -NP conjugates with short PEG linkers with an aim to increase their biocompatibility. The 50% Herceptin ® -NP conjugate group with short PEG modification to Herceptin ® showed the best reduction in immune cell uptake by 82% along with the reduction by >50% for proinflammatory cytokine response (TNF-α and IL-6). In conclusion, optimum Herceptin ® coverage with improved hydrophilic profile results in reduced phagocytic uptake and immunogenicity of engineered NP-antibody conjugates, potentially minimizing their undesirable off-target effects as a drug delivery vehicle. [ABSTRACT FROM AUTHOR]