Search

To investigate how the petroleum industry evaluates and selects powerful cloud service providers, first, an evaluation index system including 25 indices such as scalability and private data protection is built. This index system can systematically examine the comprehensive strengths of cloud service providers. Aiming to solve the problems that the traditional expert evaluation method has high requirements on expert experience and is easily affected by subjective factors, a novel artificial intelligence evaluation model named TentISSA-BPNN is proposed. The objective evaluation ability of this model can be effectively used in evaluation research on cloud service providers for petroleum enterprises. In this model, the SSA algorithm is optimized by Tent chaotic mapping and adaptive inertia weight; an algorithm, TentISSA, that has good stability and fast convergence speed is designed and proposed; and the BPNN is improved with TentISSA to obtain more accurate evaluation results. To evaluate the performance of the TentISSA algorithm, nine unimodal and multimodal functions are selected in this paper to test the convergence accuracy. Then, seven models are selected as the control groups to validate the effectiveness and performance of the TentISSA-BPNN evaluation model proposed in this paper. Finally, the preprocessed data of the candidate cloud service providers are input into the trained neural network model proposed in this paper for evaluation. Based on the ranking of the evaluation scores, the comprehensive strengths of the cloud service providers are obtained to provide a decision-making reference for managers of petroleum enterprises in the process of choosing cloud service providers. [ABSTRACT FROM AUTHOR]

Giant viruses are a large group of viruses that infect many eukaryotes. Although components that do not obey the overall icosahedral symmetry of their capsids have been observed and found to play critical roles in the viral life cycles, identities and high-resolution structures of these components remain unknown. Here, by determining a near-atomic-resolution, five-fold averaged structure of Paramecium bursaria chlorella virus 1, we unexpectedly found the viral capsid possesses up to five major capsid protein variants and a penton protein variant. These variants create varied capsid microenvironments for the associations of fibers, a vesicle, and previously unresolved minor capsid proteins. Our structure reveals the identities and atomic models of the capsid components that do not obey the overall icosahedral symmetry and leads to a model for how these components are assembled and initiate capsid assembly, and this model might be applicable to many other giant viruses. Giant viruses are large DNA viruses with capsid diameters up to 500 nm. Given technical challenges only few high-resolution structures of viral capsids exist. Here, Shao et al. provide a nearatomic structure of giant virus PBCV-1 capsid and resolve the previously unknown asymmetric capsid components. The local capsid microenvironments created by these components provide insights into the mechanism of capsid assembly of giant viruses. [ABSTRACT FROM AUTHOR]

Quinestrol (QUN), a synthetic estrogen used as an oral contraceptive or emergency contraceptive component, has been shown to be an endocrine-disrupting chemical. To assess the environmental risk of QUN, batch equilibration experiments were conducted to investigate the adsorption–desorption of QUN in five contrasting soils from different areas of China. The leaching properties were also calculated based on the adsorption and degradation data from our previous study with the same soils. The Freundlich and Langmuir models were applied to the sorption–desorption data to examine the affinity towards QUN of the soils, which had varying physical and chemical properties. The Kf and Kfdes values of QUN in the tested soils ranged from 3.72 to 20.47 mg1−n Ln kg−1 and from 1.26 to 7.8 mg1−n Ln kg−1, respectively, and Qm ranged from 28.25 to 126.58 mg/kg. The desorption data showed that hysteresis occurred. The Kf and Kfdes values of QUN were positively correlated with the soil total organic carbon (OC) and cation exchange capacity (CEC), and it may be due to the content of TOC and CEC exhibited a positive correlation. A low mobility potential of QUN in soils was predicted and verified the adsorption results by the groundwater ubiquity score (GUS) and retardation factor (Rf). [ABSTRACT FROM AUTHOR]

Although esterase-mediated spinosad resistance has been proposed for several insects, the associated molecular mechanism remains poorly understood. In this study, we investigated the mechanism of esterase-based spinosad resistance in house flies using a susceptible strain (SSS) and a spinosad-resistant, near-isogenic line (N-SRS). Combined with the synergistic effect of DEF on spinosad in the N-SRS strain, decreased ali-esterase activity in the spinosad-resistant strain has implicated the involvement of mutant esterase in spinosad resistance in house flies. Examination of the carboxylesterase gene MdαE7 in the two strains revealed that four non-synonymous mutations (Trp251-Leu, Asp273-Glu, Ala365-Val, and Ile396-Val) may be associated with spinosad resistance in house flies. Single nucleotide polymorphism analysis further indicated a strong relationship between these four mutations and spinosad resistance. Moreover, quantitative real-time PCR revealed a female-linked MdαE7 expression pattern in the N-SRS strain, which may contribute to sex-differential spinosad resistance in house flies. [ABSTRACT FROM AUTHOR]

Disease caused by Tomato yellow leaf curl virus (TYLCV) brings serious production losses of cultivated tomato worldwide. In our previous study, two novel amino acid derivatives exerted satisfactory antiviral activities against TYLCV. In this study, the variation of TYLCV, the transcriptional expression level of Ty- 1 and the enzyme activities of POD and PPO in tomato were monitored after treatment with two amino acid derivatives to illustrate the antiviral mechanism. The results showed the symptom severity caused by TYLCV was reduced significantly by two compounds and was associated with the inhibition of viral DNA level at the early stage. Among three levels of concentration, the highest inhibition rate of CNBF-His was 40.66 % at 1000 mg/L, for CNBF-Asn, the highest inhibition rate was 36.26 % at 2000 mg/L 30 days post-inoculation. Two compounds could also enhance the activities of PPO and POD and the transcriptional expression level of Ty- 1 which correlates with plant resistance in tomato. In the field test, two compounds increased the yields of tomato and the maximum increase of yield was 37.66 %. This is the first report of novel amino acid derivatives inducing resistance in tomato plant against TYLCV. It is suggested that amino acid derivatives have the potential to be an effective approach against TYLCV in tomato plant. [ABSTRACT FROM AUTHOR]

Controlled release formulation of pesticides is highly desirable for attaining the most effective utilization of the pesticide as well as reducing environmental pollution. Nano-sized controlled release formulations can provide better penetration through cuticle and deliver the active ingredients efficiently to the targeted tissue. In this study, a novel strategy for the preparation of a nanoconjugate derived from kasugamycin with amino-modified silica was developed. The kasugamycin was connected with amino-modified silica matrix by an amide bond, which could avoid the initial burst release effectively and prolong the duration remarkably. The results showed the kasuga-silica can protect kasugamycin against photo-degradation effectively and the release rate of the active ingredient of nanoconjugate was related to the temperature, pH value, and the particle size (52.5-315.4 nm). With reduced particle size as well as increased temperature and acidity, the release of the active ingredient was faster. This amide linkage of kasuga-silica could be degraded by amidase effectively. This nanoconjugate displayed a better and a sustained bactericidal efficacy against E. coli than kasugamycin technical, which makes it a potential candidate as a controlled release conjugate for kasugamycin in the future. [ABSTRACT FROM AUTHOR]