Chemo-enzymatic synthesis of Neu5Gc-containing sialylated lactulose

Purpose: To synthesize novel sialylated lactuloses, namely, Neu5Gc-α2,3-lactulose and Neu5Gc-α2,6-lactulose.Methods: ManNGc was chemically synthesized from commercially available N-acetylmannosaime (ManNAc), which was used as the donor substrate to synthesize α-(2→3) linkage and α-(2→6) linkage sialyllactulose from lactulose via sialyltransferases-catalyzed one-pot multienzyme (OPME) approach. The sialylated products were purified by silica gel flash chromatography column. Mass spectrometry (MS) and nuclear magnetic resonance (NMR) were used to confirm the purity and characterize the structure of the new compounds.Results: Sialyllactulose with α-(2→3) linkage (Neu5Gc-α2,3-lactulose) and α-(2→6) linkage (Neu5Gc- α2,6-lactulose) were efficiently synthesized by an efficient one-pot multienzyme sialylation approach from ManNGc, sodium pyruvate, CTP, and lactulose. The molecular weight of the two products, based on mass spectral data was 648 Da while NMR data indicated the formation of sialylated glycans.Conclusion: Novel sialylated oligosaccharides have been efficiently synthesized from lactulose using highly efficient OPME sialylation approaches. Further investigations are required to ascertain the probiotic activities for possible applications in pharmaceutical and food industries.Keywords: Neu5Gc, Chemo-enzymatic synthesis, Sialylation, Sialyllactulose, Lactulos

An Inhibitory Effect of Dryocrassin ABBA on Staphylococcus aureus vWbp That Protects Mice From Pneumonia

Von Willebrand factor-binding protein (vWbp), secreted by Staphylococcus aureus (S. aureus), can activate host prothrombin, convert fibrinogen to fibrin clots, induce blood clotting, and contribute to pathophysiology of S. aureus-related diseases, including infective endocarditis, staphylococcal sepsis and pneumonia. Therefore, vWbp is an promising drug target in the treatment of S. aureus-related infections. Here, we report that dryocrassin ABBA (ABBA), a natural compound derived from Dryopteris crassirhizoma, can significantly inhibit the coagulase activity of vWbp in vitro by directly interacting with vWbp without killing the bacteria or inhibiting the expression of the vWbp. Using molecular dynamics simulations, we demonstrate that ABBA binds to the “central cavity” in the elbow of vWbp by interacting with Arg-70, His-71, Ala-72, Gly-73, Tyr-74, Glu-75, Tyr-83, and Gln-87 in vWbp, thus interfering with the binding of vWbp to prothrombin. Furthermore, in vivo studies demonstrated that ABBA can attenuate injury and inflammation of mouse lung tissues caused by S. aureus and increase survival of mice. Together these findings indicate that ABBA is a promising lead drug for the treatment of S. aureus-related infections. This is the first report of potential inhibitor which inhibit the coagulase activity of vWbp by directly interacting with vWbp

Farmers’ Attitudes and Perceptions and the Effects of the Grain for Green Project in China: A Case Study in the Loess Plateau

The Grain for Green Project (GGP) aims to protect and improve the ecological environment, end farming on sloping farmland, and plant trees and restore forest vegetation. China’s GGP has been widely implemented, but its impact on the environment is rarely evaluated from farmers’ perspectives. This study took place in Zhidan and Yanchang Counties, Shaanxi Province. Farmers’ attitudes towards the GGP were investigated through semi-structured interviews to understand their perceptions of changes in ecosystem services and their level of ecological awareness, as well as analyzing which factors had the greatest impact on them. Our results indicate that some farmers are not satisfied with the GGP and are unwilling to participate in future GGPs, which is not only due to the dissatisfaction with subsidies offered but also because the needs of the farmers have been ignored. From the perspective of farmers, the GGP has greatly reduced soil erosion and air pollution but has had no effect on improving water quality and protecting biodiversity. More male farmers are willing to participate, and farmers with higher levels of education are more satisfied with the GGP. We also found that the level of understanding of ecological cognition affected farmers’ attitudes, and farmers with different levels of knowledge differ in their willingness to participate. Our research found that many farmers were dissatisfied with the GGP. To improve this situation, it is necessary to improve the ecological awareness of farmers. At the same time, policy makers should also further understand the needs of farmers in order to make reasonable management strategies

The Scale and Revenue of the Land-Use Balance Quota in Zhejiang Province: Based on the Inverted U-Shaped Curve

The project-based construction land-use policy of ‘increasing versus decreasing balance’ (IVDB) is pivotal to easing the contradiction between urban and rural land in China. Understanding the relationship between the scale and revenue of the balanced quota is crucial for increasing the efficiency of quota-allocated, and further improving, IVDB performance. However, existing studies have rarely revealed the impact of the balanced quota’s scale on its revenue, supported through empirical evidence. In this study, we analyzed the relationship between the scale and revenue of the balanced quota and used the quadratic econometric model to explore the inverted U-shaped impact of the scale of the balanced quota on the revenue of the 1907 IVDB projects in Zhejiang province. The results show that: (1) the relationship between the quota’s scale and the revenue shows an inverted ‘U’ type in Zhejiang. On the premise of considering three control variable groups, the optimally balanced quota of Zhejiang province is 7.19 ha. (2) There is spatial heterogeneity in the optimal scale of the balanced quota in Zhejiang and the appreciated scale of the quota in northeast and southwest Zhejiang is 9.50 ha and 6.03 ha, respectively. Then we discussed problems associated with the scale and revenue of the project-based balanced quota under the implementation of the IVDB policy. The study enriches the performance analysis of IVDB policy from the point of view of economic perspective and tries to provide a scientific basis for the appropriate size quota for local government. Finally, comprehensive consideration of inputs to allocate the balanced quota, optimizing the rural resettlements spatial planning, and strengthening central-government supervision is put forward

Optimal Unmanned Combat System-of-Systems Reconstruction Strategy with Heterogeneous Cost via Deep Reinforcement Learning

The unmanned combat system-of-systems (UCSoS) in modern warfare is comprised of various interconnected entities that work together to support mission accomplishment. The soaring number of entities makes the UCSoS fragile and susceptible to triggering cascading effects when exposed to uncertain disturbances such as attacks or failures. Reconfiguring the UCSoS to restore its effectiveness in a self-coordinated and adaptive manner based on the battlefield situation and operational requirements has attracted increasing attention. In this paper, we focus on the UCSoS reconstruction with heterogeneous costs, where the collaboration nodes may have different reconstruction costs. Specifically, we adopt the heterogeneous network to capture the interdependencies among combat entities and propose a more representative metric to evaluate the UCSoS reconstruction effectiveness. Next, we model the combat network reconstruction problem with heterogeneous costs as a nonlinear optimization problem and prove its NP-hardness. Then, we propose an approach called SoS-Restorer, which is based on deep reinforcement learning (DRL), to address the UCSoS reconstruction problem. The results show that SoS-Restorer can quickly generate reconstruction strategies and improve the operational capabilities of the UCSoS by about 20∼60% compared to the baseline algorithm. Furthermore, even when the size of the UCSoS exceeds that of the training data, SoS-Restorer exhibits robust generalization capability and can efficiently produce satisfactory results in real time

Structural optimization and characteristics of a novel single-ended pressure vessel with inside and outside tubes

A new type of inside and outside tubes differential pressure flowmeter was designed. The throat structure and single-end pressure tapping method is proposed. Three-dimensional numerical simulation is used for structural optimization. The experimental prototype is processed and calibrated in real-time. It was found that the differential pressure values of the new flowmeter was 3.4 times higher and pressure loss ratio only 20% of the original flowmeter in forward flow, while 2.6 times higher and pressure loss ratio only 25% in reverse flow. The sensitivity and energy efficiency of the novel flowmeter is shown to be significantly improved

When Optimization Meets AI: An Intelligent Approach for Network Disintegration with Discrete Resource Allocation

Network disintegration is a fundamental issue in the field of complex networks, with its core in identifying critical nodes or sets and removing them to weaken network functionality. The research on this problem has significant strategic value and has increasingly attracted attention, including in controlling the spread of diseases and dismantling terrorist organizations. In this paper, we focus on the problem of network disintegration with discrete entity resources from the attack view, that is, optimizing resource allocation to maximize the effect of network disintegration. Specifically, we model the network disintegration problem with limited entity resources as a nonlinear optimization problem and prove its NP-hardness. Then, we design a method based on deep reinforcement learning (DRL), Net-Cracker, which transforms the two-stage entity resource and network node selection task into a single-stage object selection problem. Extensive experiments demonstrate that compared with the benchmark algorithm, Net-Cracker can improve the solution quality by about 8∼62%, while enabling a 30-to-160-fold speed up. Net-Cracker also exhibits strong generalization ability and can find better results in a near real-time manner even when the network scale is much larger than that in training data

Measurement of interfacial shear stress in gas–liquid two-phase stratified flow

From Crossref journal articles via Jisc Publications RouterHistory: epub 2023-10-26, issued 2023-10-26, ppub 2023-10-28Publication status: PublishedFunder: National Natural Science Foundation of China; FundRef: https://doi.org/10.13039/10.13039/501100001809; Grant(s): 62173122Funder: Key Project of Natural Science Foundation of Hebei Province; Grant(s): F2021201031Funder: Beijing-Tianjin-Hebei Collaborative Innovation Community Construction Project; Grant(s): 20540301DFunder: Natural Science Foundation of Hebei Province; FundRef: https://doi.org/10.13039/10.13039/501100003787; Grant(s): F2022201034Funder: Hebei Provincial Postgraduate Demonstration Course Project; Grant(s): KCJSX2021009Gas–liquid two-phase stratified flow exists in many industrial processes. Although the flow pattern is simple, the interfacial shear prediction of stratified flow is still the focus of the study. The calculation of the shear stress at the gas–liquid interface is closely related to the measurement of the void fraction and pressure drop of the stratified flow. In this study, a new method for the calculation of interfacial shear stress of gas–liquid two-phase stratified flow is proposed. Differential pressure measurement and planar laser-induced fluorescence technology are combined to obtain important parameters for stratified flow under low-speed flow conditions (Ql = 0.10–0.25 m3/h, Qg = 0.35–1.00 m3/h). The interfacial shear stress is successfully calculated using macroparameters. The uncertainty associated with the calculated parameters using the proposed method is 2.67%, and this study verifies the accuracy of the linear relationship. The method provides a new way to obtain the interfacial shear stress of gas–liquid stratified flow

Effects of artificial aging on physiological quality and cell ultrastructure of maize (Zea mays L.)

‘Qiule 368’ (flour maize) and ‘Zhengdan 958’ (flint maize) seeds were artificially aged at 46 °C and 95% relative humidity to investigate the changes in physiological quality of maize seeds during aging. The vigor of the seeds, their reactive oxygen species (ROS) content, cell membrane status, antioxidant enzyme system, and cellular ultrastructure were all investigated. The results showed that the germination energy, germination rate, superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities decreased during artificial aging, whereas the content of malondialdehyde (MDA), hydrogen peroxide (H2O2), superoxide anion (O2·–), and carbonyl protein as well as relative electrical conductivity (REC) increased during artificial aging. SOD and CAT activities showed highly significant negative correlation with aging time (p < 0.01), MDA, H2O2, O2·– content and REC showed highly significant positive correlation with aging time (p < 0.01), whereas POD activity showed significant negative correlation with aging time (p < 0.05). After aging, the cell membrane ruptured, and negative changes in amyloplast and protein bodies and in liposomes were all observed. This study provided guidelines for the meaningful study of changes in maize seed physiological quality during storage