High-surface-area organic matrix tris(aza)pentacene supported platinum nanostructures as selective electrocatalyst for hydrogen oxidation/evolution reaction and suppressive for oxygen reduction reaction

Developing a Pt-based electrocatalytic material able to selectively catalyze hydrogen oxidation (HOR) while supressing oxygen reduction (ORR) is beneficial for durability of the fuel cells. Namely, degradation of carbon supported Pt particles is dramatically influenced by the unwanted ORR enrolling at the anode due to the air penetration during start-up/shut-down events. We present an organic matrix tris(aza)pentacene (TAP), which belongs to π-functional materials with ladder-like conjugated nitrogen-containing units, as the support for Pt to form a “smart” fuel cell anode able to selectively catalyze HOR and to suppress ORR. “Switching-on/off” of the composite material activity is provided by reversible reduction/oxidation of the TAP in the low potential region which provokes TAP - H_xTAP transition. Conductivity of the reduced H_xTAP enables supported Pt particles to effectively run HOR. In contrast, restricted conductivity of oxidized TAP analogue leads to the substantial drop in the ORR activity with respect to benchmark Pt/C catalyst.     

Numerical,wind-tunnel,and atmospheric evaluation of a turbulent ground-based inlet sampling system

The use of inlets for transferring aerosols from the environment to instrumentation can introduce uncertainty in the measurement of aerosol properties. Aerosol loss during this process is a non-negligible issue that may bias the subsequent measurements. These loss mechanisms include aspiration at the inlet head and deposition/evaporation/condensation during transport through the sampling lines. Coarse-mode aerosol is significantly impacted by the aspiration and inertial loss mechanisms within an inlet system. This work uses wind tunnel experiments to investigate aerosol losses through the Storm Peak Laboratory’s (SPL) new aerosol inlet system. The inlet is used extensively for both intensive field campaigns and long-term aerosol monitoring. The results of numerical simulations of the SPL aerosol inlet sampling efficiency are provided at several wind speeds, and experimental results demonstrate the system has a 50% cut off for the coarse-mode at an aerodynamic diameter of approximately 13?μm and wind speed of 0.5?m s^?1. This investigation will lead to improved accuracy of in situ aerosol measurements at SPL and this system can be replicated at other atmospheric stations.

Copyright © 2019 American Association for Aerosol Research     

Enhanced photocatalytic H2 evolution over In2S3 via decoration with GO and Fe2P co-catalysts

In this study, GO and Fe₂P were used as co-catalysts to improve the separation efficiency of photogenerated electron-hole pairs in an In₂S₃ photocatalyst. The metallic character of Fe₂P provided a cheap substitute for traditional noble metal co-catalyst for H₂ production in aqueous media. The GO/Fe₂P/In₂S₃ composite demonstrated significantly enhanced photocatalytic activity compared to pure In₂S₃, delivering a H₂ production rate of 483.35 μmol h^?1 g^?1 and a quantum yield was 22.68% under visible light irradiation. The design of the photocatalyst was optimized using “Design Expert” software. The analysis showed that a GO loading of 1.18 wt%, a Fe loading of 5.36 wt%, and a calcination temperature of 180 °C were optimal.     

E7766, a Macrocycle-Bridged Stimulator of Interferon Genes (STING) Agonist with Potent Pan-Genotypic Activity

A strategy for creating potent and pan-genotypic stimulator of interferon genes (STING) agonists is described. Locking a bioactive U-shaped conformation of cyclic dinucleotides by introducing a transannular macrocyclic bridge between the nucleic acid bases leads to a topologically novel macrocycle-bridged STING agonist (MBSA). In addition to substantially enhanced potency, the newly designed MBSAs, exemplified by clinical candidate E7766 , exhibit broad pan-genotypic activity in all major human STING variants. E7766 is shown to have potent antitumor activity with long lasting immune memory response in a mouse liver metastatic tumor model. Two complementary stereoselective synthetic routes to E7766 are also described.     

A new correlation for the coefficient of restitution of particles with low mechanical resistance for modeling wastewater treatment biofilm reactors

Clean Technologies and Environmental Policy - Fluidized bed bioreactors are widely used in wastewater treatment applications. Such reactors employ gel beads or hard particles covered with a biofilm...     

Influence of Ni and Process Parameters in Medium Mn Steels Heat Treated by High Partitioning Temperature Q&P Cycles

In this work, two medium Mn steels (5.8 and 5.7 wt pct Mn) were subjected to a quenching and partitioning (Q&P) treatment employing a partitioning temperature which corresponded to the start of austenite reverse transformation (ART). The influence of a 1.6 wt pct Ni addition in one of the steels and cycle parameters on austenite stability and mechanical properties was also studied. High contents of retained austenite were obtained in the lower quenching temperature (QT) condition, which at the same time resulted in a finer microstructure. The addition of Ni was effective in stabilizing higher contents of austenite. The partitioning of Mn and Ni from martensite into austenite was observed by TEM–EDS. The partitioning behaviour of Mn depended on the QT condition. The lower QT condition facilitated Mn enrichment of austenite laths during partitioning and stabilization of a higher content of austenite. The medium Mn steel containing Ni showed outstanding values of the product of tensile strength (TS) and total elongation (TEL) in the lower QT condition and a higher mechanical stability of the austenite.

     

Characterization and selection of suitable grades of lactose as functional fillers for capsule filling: part 1

The purpose of this work is to characterize thermal, physical and mechanical properties of different grades of lactose and better understand the relationships between these properties and capsule filling performance. Eight grades of commercially available lactose were evaluated: Pharmatose 110?M, 125?M, 150?M, 200?M, 350?M (α-lactose monohydrate), AL (anhydrous lactose containing ～80% β-AL), DCL11 (spray dried α-lactose monohydrate containing ～15% amorphous lactose) and DCL15 (granulated α-lactose monohydrate containing ～12% β-AL). In this study, different lactose grades were characterized by thermal, solid state, physical and mechanical properties and later evaluated using principal component analysis (PCA) to assess the inter-relationships among some of these properties. The lactose grades were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), moisture sorption/desorption isotherms, particle size distribution; the flow was characterized by Carr Index (CI), critical orifice diameter (COD) and angle of friction. Plug mechanical strength was estimated from its diametric crushing strength. The first and second principal components (PC) captured 47.6% and 27.4% of variation in the physical and mechanical property data, respectively. The PCA plot grouped together 110?M, AL, DCL11 and DCL15 on the one side of plot which possessed superior properties for capsule formulation and these grades were selected for future formulation development studies (part II of this work).     

Multi-breath dry powder inhaler for delivery of cohesive powders in the treatment of bronchiectasis

A series of co-engineered macrolide–mannitol particles were successfully prepared using azithromycin (AZ) as a model drug. The formulation was designed to target local inflammation and bacterial colonization, via the macrolide component, while the mannitol acted as mucolytic and taste-masking agent. The engineered particles were evaluated in terms of their physico-chemical properties and aerosol performance when delivered via a novel high-payload dry powder Orbital^? inhaler device that operates via multiple inhalation manoeuvres. All formulations prepared were of suitable size for inhalation drug delivery and contained a mixture of amorphous AZ with crystalline mannitol. A co-spray dried formulation containing 200?mg of 50:50?w/w AZ: mannitol had 57.6%?±?7.6% delivery efficiency with a fine particle fraction (≤6.8?µm) of the emitted aerosol cloud being 80.4%?±?1.1%, with minimal throat deposition (5.3?±?0.9%). Subsequently, it can be concluded that the use of this device in combination with the co-engineered macrolide–mannitol therapy may provide a means of treating bronchiectasis.