Repurposing Multi-Targeting Plant Natural Product Scaffolds In Silico Against SARS-CoV-2 Non-Structural Proteins Implicated in Viral Pathogenesis

<p>Background: Accessing COVID-19 vaccines is a challenge despite successful clinical trials. This burdens the COVID-19 treatment gap, thereby requiring accelerated discovery of anti-SARS-CoV-2 agents. Thus, this study explored the potential of anti-HIV reverse transcriptase (RT) phytochemicals as inhibitors of SARS-CoV-2 non-structural proteins (nsps) by targeting <i>in silico</i> key sites in the structures of SARS-CoV-2 nsps. Moreover, structures of the anti-HIV compounds were considered for druggability and toxicity. 104 anti-HIV phytochemicals were subjected to molecular docking with papain-like protease (nsp3), 3-chymotrypsin-like protease (nsp5), RNA-dependent RNA polymerase (nsp12), helicase (nsp13), SAM-dependent 2’-<i>O-</i>methyltransferase (nsp16) and its cofactor (nsp10), and endoribonuclease (nsp15). Drug-likeness and ADME (absorption, distribution, metabolism, and excretion) properties of the top ten compounds per nsp were predicted using SwissADME. Their toxicity was also determined using OSIRIS Property Explorer.</p> <p>Results: Among the twenty-seven top-scoring compounds, the polyphenolic natural products amentoflavone (<b>1</b>), robustaflavone (<b>4</b>), punicalin (<b>9</b>), volkensiflavone (<b>11</b>), rhusflavanone (<b>13</b>), morelloflavone (<b>14</b>), hinokiflavone (<b>15</b>), and michellamine B (<b>19</b>) were multi-targeting and had the strongest affinities to at least two of the nsps (Binding Energy = -7.7 to -10.8 kcal/mol). Friedelin (<b>2</b>), pomolic acid (<b>5</b>), ursolic acid (<b>10</b>), garcisaterpenes A (<b>12</b>), hinokiflavone (<b>15</b>), and digitoxigenin-3-<i>O-</i>glucoside (<b>17</b>) were computationally druggable. Moreover, compounds <b>5</b> and <b>17</b> showed good gastrointestinal absorptive property. Most of the compounds were also predicted to be non-toxic.</p> <p>Conclusions: Twenty anti-HIV RT phytochemicals showed multi-targeting inhibitory potential against SARS-CoV-2 nsp3, 5, 10, 12, 13, 15, and 16, and can therefore be used as prototypes for anti-COVID-19 drug design.</p>

Repurposing Multi-Targeting Plant Natural Product Scaffolds In Silico Against SARS-CoV-2 Non-Structural Proteins Implicated in Viral Pathogenesis

<p>Background: Accessing COVID-19 vaccines is a challenge despite successful clinical trials. This burdens the COVID-19 treatment gap, thereby requiring accelerated discovery of anti-SARS-CoV-2 agents. Thus, this study explored the potential of anti-HIV reverse transcriptase (RT) phytochemicals as inhibitors of SARS-CoV-2 non-structural proteins (nsps) by targeting <i>in silico</i> key sites in the structures of SARS-CoV-2 nsps. Moreover, structures of the anti-HIV compounds were considered for druggability and toxicity. 104 anti-HIV phytochemicals were subjected to molecular docking with papain-like protease (nsp3), 3-chymotrypsin-like protease (nsp5), RNA-dependent RNA polymerase (nsp12), helicase (nsp13), SAM-dependent 2’-<i>O-</i>methyltransferase (nsp16) and its cofactor (nsp10), and endoribonuclease (nsp15). Drug-likeness and ADME (absorption, distribution, metabolism, and excretion) properties of the top ten compounds per nsp were predicted using SwissADME. Their toxicity was also determined using OSIRIS Property Explorer.</p> <p>Results: Among the twenty-seven top-scoring compounds, the polyphenolic natural products amentoflavone (<b>1</b>), robustaflavone (<b>4</b>), punicalin (<b>9</b>), volkensiflavone (<b>11</b>), rhusflavanone (<b>13</b>), morelloflavone (<b>14</b>), hinokiflavone (<b>15</b>), and michellamine B (<b>19</b>) were multi-targeting and had the strongest affinities to at least two of the nsps (Binding Energy = -7.7 to -10.8 kcal/mol). Friedelin (<b>2</b>), pomolic acid (<b>5</b>), ursolic acid (<b>10</b>), garcisaterpenes A (<b>12</b>), hinokiflavone (<b>15</b>), and digitoxigenin-3-<i>O-</i>glucoside (<b>17</b>) were computationally druggable. Moreover, compounds <b>5</b> and <b>17</b> showed good gastrointestinal absorptive property. Most of the compounds were also predicted to be non-toxic.</p> <p>Conclusions: Twenty anti-HIV RT phytochemicals showed multi-targeting inhibitory potential against SARS-CoV-2 nsp3, 5, 10, 12, 13, 15, and 16, and can therefore be used as prototypes for anti-COVID-19 drug design.</p>

Wideband RCS Reduction of Microstrip Array Antenna Based on Absorptive Frequency Selective Surface and Microstrip Resonators

An approach for wideband radar cross section (RCS) reduction of a microstrip array antenna is presented and discussed. The scheme is based on the microstrip resonators and absorptive frequency selective surface (AFSS) with a wideband absorptive property over the low band 1.9–7.5 GHz and a transmission characteristic at high frequency 11.05 GHz. The AFSS is designed to realize the out-of-band RCS reduction and preserve the radiation performance simultaneously, and it is placed above the antenna with the operating frequency of 11.05 GHz. Moreover, the microstrip resonators are loaded to obtain the in-band RCS reduction. As a result, a significant RCS reduction from 1.5 GHz to 13 GHz for both types of polarization has been accomplished. Compared with the reference antenna, the simulated results exhibit that the monostatic RCS of the proposed array antenna in x- and y-polarization can be reduced as much as 17.6 dB and 21.5 dB, respectively. And the measured results agree well with the simulated ones.

Time Domain Waveform Inversion for theQModel Based on the First-Order Viscoacoustic Wave Equations

Propagating seismic waves are dispersed and attenuated in the subsurface due to the conversion of elastic energy into heat. The absorptive property of a medium can be described by the quality factorQ. In this study, the first-order pressure-velocity viscoacoustic wave equations based on the standard linear solid model are used to incorporate the effect ofQ. For theQmodel inversion, an iterative procedure is then proposed by minimizing an objective function that measures the misfit energy between the observed data and the modeled data. The adjoint method is applied to derive the gradients of the objective function with respect to the model parameters, that is, bulk modulus, density, andQ-related parameterτ. Numerical tests on the crosswell recording geometry indicate the feasibility of the proposed approach for theQanomaly estimation.

Preparation of a New Oil Absorbing Polyurethane Foam

Oil absorbing foam as a new type of the oil absorbing material, its oil absorptive property had a very important researching value in oil spill emergency disposal and the treatment of oily wastewater in daily life and laboratory. Polyurethane foam was used as a basal body material and silicone was used as modifier for the surface-modification to an excellent new kind of polyurethane flexible foam. This kind of foam has the quality of high oil-absorbing and low water-absorbing, by changing the potency of silicone and the amount of polyurethane to get the best treatment plan. The results show that the absorption of per gram of this new kind of foam is 16.89g edible oil, 24.86g diesel oil or 26.89g gasoline.

Study on Amphiphilic Macromolecules Adsorbent of Cellulose Mixes Ether Based on Cotton Stalk

in this work, the organic macromolecules adsorbent cyanoethylated carboxymethyl cellulose having hydrophilic and lipophilicity characteristics were preparated through properly carboxymethylation and cyanoethylation process, basing on cotton stalk cellulose treated by steam explosion as raw material, which the content of cellulose in the product is 72.6%. The effect of carboxymethylation degree on cyanoethylation degree was discussed. Then its characteristics of solubility, thermal properties, acid resistance and absorptive property were researched