No abstract

Viral diseases have contributed significantly to worldwide morbidity and mortality throughout history. Despite the existence of therapeutic treatments for many viral infections, antiviral resistance and the threat posed by novel viruses highlight the need for an increased number of effective therapeutics. In addition to small molecule drugs and biologics, antimicrobial peptides (AMPs) represent an emerging class of potential antiviral therapeutics. While AMPs have traditionally been regarded in the context of their antibacterial activities, many AMPs are now known to be antiviral. These antiviral peptides (AVPs) have been shown to target and perturb viral membrane envelopes and inhibit various stages of the viral life cycle, from preattachment inhibition through viral release from infected host cells. Rational design of AMPs has also proven effective in identifying highly active and specific peptides and can aid in the discovery of lead peptides with high therapeutic selectivity. In this review, we highlight AVPs with strong antiviral activity largely curated from a publicly available AMP database. We then compile the sequences present in our AVP database to generate structural predictions of generic AVP motifs. Finally, we cover the rational design approaches available for AVPs taking into account approaches currently used for the rational design of AMPs.

Selective adsorption of ethane from a mixture of ethane (C 2 H 6 ) and ethylene (C 2 H 4 ) has emerged as an energy-efficient process for obtaining high-purity ethylene. Recently, it has been reported that some novel microporous organometallic and organic adsorbents can preferentially adsorb C 2 H 6 over C 2 H 4 . Conversely, zeolite adsorbents, which are widely used in industry due to their high stability and low material cost, generally prefer C 2 H 4 adsorption ("olefin-philic"). In this study, we carefully investigated the effects of chemical composition (Si/ Al ratio), silanol defect, and pore topology (BEA, CHA, and MFI) of zeolites to develop efficient "olefin-phobic" adsorbents. The results showed that the Si−O−(Na + )−Al (weak Lewis acid) and isolated Si− OH (weak Brønsted acid) groups in the zeolite frameworks undesirably increased the affinity for C 2 H 4 (Lewis base). Consequently, defect-free pure silica zeolites exhibited promising C 2 H 6 /C 2 H 4 selectivities (1.98−2.25), which were superior to those of Al-containing zeolites (0.26) and pure silica zeolites with abundant silanols (1.50), at 298 K and 1 bar. In particular, defect-free pure silica BEA exhibited the highest C 2 H 6 /C 2 H 4 selectivity (2.25), large C 2 H 6 uptake (2.27 mmol g −1 ), and facile regeneration at 298 K. The adsorbent enabled the efficient separation of high-purity C 2 H 4 (>99.95%) from a mixture of C 2 H 6 /C 2 H 4 with high productivity (22.98 L L −1 ). The productivity was comparable or even superior to that of recently reported C 2 H 6 -selective adsorbents. The present results provide hope for the development of efficient, stable, and scalable inorganic adsorbents for the selective C 2 H 6 adsorption.

The concept of designing mechanically stabilized earth (MSE) walls is divided into internal and external stability review methods, and one of the design factors required in internal stability analysis is the frictional characteristics between soil and geogrids for civil engineering applications. Typical methods for evaluating the frictional characteristics between soil and geogrids include the direct shear test and pullout test. It is desirable to apply the pullout test to geogrid reinforcements for pulling out geogrids embedded in soil, to measure both the surface-frictional force and passive resistance at the same time. Pullout parameters can be significantly affected by confining the stress and tensile strength of reinforcements. In general, the pullout parameters tend to be overestimated for low confining stresses in the pullout test, and underestimated for high confining stresses. Therefore, to address these issues, this study aims to evaluate the influence of the confining stress and the tensile strength of a geogrid reinforcement in the pullout test, and to propose a reasonable method for obtaining practical pullout parameters. Based on the pullout tests, the maximum pullout force depending on the tensile strength of the geogrid reinforcement was measured for one-third of the reinforcement tensile strength, and it was ruptured when pullout force greater than the maximum pullout force was exerted. Furthermore, it was observed that, in the reinforcement pullout test, pullout force was measured in the whole area of the reinforcement at a confining stress smaller than one-half of the tensile strength of the grid. As a result, the effective confining stress method considering only the confining stress at which the reinforcement is fully pulled out to develop the pullout characteristics can be a practical method for obtaining pullout parameters without regard to the reinforcement tensile strength.

Amine-containing adsorbents have been widely investigated for capturing CO 2 but suffer from rapid oxidative degradation. We recently reported that ppm-level metal impurities (Fe and Cu) in commercial amine polymers can accelerate the oxidative degradation of these aminecontaining adsorbents, which can be suppressed by adding chelators such as phosphate. In the present study, we investigated the amine-stabilization effects of monocationic phosphate salts containing cations of different charge densities, such as Li + , Na + , tetramethylammonium (TMA + ), and tetraethylammonium (TEA + ). The results showed that phosphate salts containing organophilic cations of low charge densities can effectively stabilize amine polymers. Such organophilic phosphate salts might be better dispersed within the organic amine polymers and have a loosely associated ion-pair form, which is beneficial for binding with metal impurities. Consequently, the adsorbent stabilized with the most organophilic TEAH 2 PO 4 exhibited unprecedentedly high stability; specifically, it showed a very minor decrease in CO 2 capacity (<3.5%) even after 1 month of aging in O 2 -containing flue gas at 110 °C.