Two Rules on the Protein-Ligand Interaction

So far, we still lack a clear molecular mechanism to explain the protein-ligand interaction on the basis of electronic structure of a protein. By combining the calculation of the full electronic structure of a protein along with its hydrophobic pocket and the perturbation theory, we found out two rules on the protein-ligand interaction. One rule is the interaction only occurs between the lowest unoccupied molecular orbitals (LUMOs) of a protein and the highest occupied molecular orbital (HOMO) of its ligand, not between the HOMOs of a protein and the LUMO of its ligand. The other rule is only those residues or atoms located both on the LUMOs of a protein and in a surface pocket of a protein are activity residues or activity atoms of the protein and the corresponding pocket is the ligand binding site. These two rules are derived from the characteristics of energy levels of a protein and might be an important criterion of drug design

Study of the Electrical Power Network Harmonic Analysis Algorithm Technology Based on Gradient Blind Signal Separation

A large amount of electrical power harmonic are injected into the electrical power network because the widely used of nonlinear electrical power load. It brings a great harm to the precision electronic instrument in safety running. This article presented a kind of electrical network harmonic analysis algorithm used for the harmonic signal separation. Through analyzing the harmonic monitor technology at present, using the blind signal separation technology to complete the mixing electrical power system voltage signal separation based on the traditional information maximization blind source separation algorithm and natural gradient algorithm, the simulation result shown that this two algorithm can also realize the instantaneous mixing voltage harmonic signal separation and harmonic analysis monitor. The result expressed that this method can effectively gain a good separation effect with the monitoring spectrum error is less than 1 %

Response behavior of antibiotic resistance genes and human pathogens to slope gradient and position: an environmental risk analysis in sloping cultivated land

Soils, especially in farmlands, are key media for the transmission of antibiotic resistance genes (ARGs) and their hosts from the environment to humans. Sloping farmland is an important agricultural resource, but there lack of studies on the fate and risk of ARGs in sloping land. Also, the behavior and drivers of ARGs in response to slope gradient and position are unclear. Here, metagenomics was used to investigate the profiles of ARGs, mobile genetic elements, and microbial communities in soils from lands of five slope gradients (5°, 10°, 15°, 20°, and 25°) with two slope positions (uphill and downhill). Results showed that while the abundance (except 15°) and diversity (except 20°) of ARGs increased as the slope gradient increased, the diversity of ARGs with health risk, especially the high-risk ones, decreased. For slope positions, abundant and diverse ARGs were more likely to accumulate at downhill. Furthermore, 52 bacterial genera and 12 human pathogenic bacteria (HPB) species were identified as the potential hosts for ARGs with high risk, and abundant HPB species were also detected in the soils with low gradients at downhill. Moreover, the structural equation model analysis revealed that the slope gradient and the slope position have both direct and indirect effects on the abundance of ARGs. Further correlation analysis revealed that the slope gradient has a positive effect (p < 0.05) on nitrite nitrogen in the soils. Also, the slope position has a negative effect (p < 0.05) on total phosphorus and microbial nitrogen, while positively affected (p < 0.05) on particulate nitrogen and microbial carbon, which were the key factors driving the behavior of ARGs. Overall, this study provided comprehensive information on ARGs with health risks and their potential pathogenic hosts in sloping farmland. It can be important for controlling antibiotic resistance transmission and be consistent with the One Health framework

On the Nature of GW190814 and Its Impact on the Understanding of Supranuclear Matter

The observation of a compact object with a mass of 2.50-2.67Me on 2019 August 14, by the LIGO Scientific and Virgo collaborations (LVC) has the potential to improve our understanding of the supranuclear equation of state. While the gravitational-wave analysis of the LVC suggests that GW190814 likely was a binary black hole system, the secondary component could also have been the heaviest neutron star observed to date. We use our previously derived nuclear-physics-multimessenger astrophysics framework to address the nature of this object. Based on our findings, we determine GW190814 to be a binary black hole merger with a probability of >99.9%. Even if we weaken previously employed constraints on the maximum mass of neutron stars, the probability of a binary black hole origin is still ∼81%. Furthermore, we study the impact that this observation has on our understanding of the nuclear equation of state by analyzing the allowed region in the mass-radius diagram of neutron stars for both a binary black hole or neutron star-black hole scenario. We find that the unlikely scenario in which the secondary object was a neutron star requires rather stiff equations of state with a maximum speed of sound cs ≥0.6 times the speed of light, while the binary black hole scenario does not offer any new insight

Multimessenger constraints on the neutron-star equation of state and the Hubble constant

Observations of neutron-star mergers with distinct messengers, including gravitational waves and electromagnetic signals, can be used to study the behavior of matter denser than an atomic nucleus and to measure the expansion rate of the Universe as quantified by the Hubble constant. We performed a joint analysis of the gravitational-wave event GW170817 with its electromagnetic counterparts AT2017gfo and GRB170817A, and the gravitational-wave event GW190425, both originating from neutron-star mergers. We combined these with previous measurements of pulsars using X-ray and radio observations, and nuclear-theory computations using chiral effective field theory, to constrain the neutron-star equation of state. We found that the radius of a 1:4-solar mass neutron star is 11:75þ0:86_0:81 km at 90% confidence and the Hubble constant is 66:2þ4:4_4:2 at 1s uncertainty

Asexual proliferative seedling technology for Sargassum fusiforme constructed using tissue culture method

The traditional method of sexual reproduction in Sargassum fusiforme can lead to difficulties in maintaining the stable inheritance of superior traits. However, technology for asexual proliferation of seedlings in seaweed tissue culture is not well-developed. Therefore, we established a tissue culture method to study, the effects of different parts of S. fusiforme, uniconazole (UIZ) concentrations, and culture methods on the regeneration of tissue-derived juveniles of S. fusiforme. The results showed that the optimal culture conditions were solid medium with modified Provassoli’s enriched seawater containing 3 μM UIZ for at least 17 days followed by transfer to liquid medium to induce rapid cell proliferation. These optimal conditions resulted in a callus-like/adventitious bud induction rate of 100%, callus-like/adventitious bud number per explant of 27.43 ± 4.57, and relative growth rate of 3.05 ± 0.27. The best plant parts for tissue culture were the filamentous holdfasts followed by the stem tip. In addition, UIZ treatment increased photosynthesis, resulting in soluble sugar and soluble protein contents of 30.47 mg·g-1 and 1.39 mg·g-1 of in the regenerated juveniles. Based on our results, S. fusiforme can be cultured using a tissue culture technique in which UIZ is added to a solid medium, followed by culture in liquid medium for proliferation. Sargassum fusiforme juveniles obtained using this technique can be cultured continuously until the next culture season and grow normally, providing a technical reference for indoor preservation and expansion of algal species