Search

Palladium-catalyzed 2-substituted quinazolin-4(3H)-one formation from readily available o-nitrobenzamides and alcohols using hydrogen transfer is described. Various quinazolin-4(3H)-ones were obtained in good to high yields. The cascade reaction including alcohol oxidation, nitro reduction, condensation, and dehydrogenation occurs without any added reducing or oxidizing agent.

Current progress on biobased thermosetting epoxy focuses on developing high thermomechanical properties. However, its functional applications that represent a significant subject for future trends ...

The stability and durability of laser-induced graphene (LIG) patterns embedded in polymer substrates are significant for their practical application. However, most of currently reported LIG precursors are facing the dilemma of weak structural controllability, poor resistance to acid/base, or bad processability. In this work, we efficiently converted the synthesized poly (Ph-ddm) into LIG using a straightforward CO2 laser, aiming to find a potential LIG precursor with excellent durability under harsh conditions. The graphene structure of obtained LIG was confirmed by Raman spectra, scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Results indicated that the poly (Ph-ddm)-based LIG showed a low sheet resistance of 35 Ω/sq as well as a high specific surface area of 883 m2/g. And due to the superior properties of poly (Ph-ddm), the LIG patterns exhibited excellent resistance to strong acid/base solutions and high adhesion on the substrate, which ensured their stable application under severe conditions. Besides, potential application of as-prepared LIG was demonstrated in well-performed supercapacitors and electrode for water splitting in an alkaline medium. Based on the results in this work, polybenzoxazine could be a promising precursor for stable and durable LIG preparation.

Determining critical ecological protected areas at the city (county) spatial scale is crucial for coordinating regional ecological environment management, control, and governance. It is a recognized consensus in academia that human activities significantly impact natural ecosystems. Many scholars ignore this point in the research process and only use several factors to characterize human influence. Therefore, this study takes Aksu City and Wensu County, important cities and towns in southern Xinjiang, as examples, focusing on the impact of human activities on the distribution of critical ecological protection areas. First, we simulated the range, intensity, and local natural conditions of human activities in the study area using geospatial data. We created corresponding resistance surfaces (human activity resistance surface and natural landscape resistance surface). We then assign different weights to the two resistance surfaces based on several possible scenarios, resulting in different synthetic resistance surfaces. Finally, we used the Linkage Mapper plugin to identify critical ecological reserves and compared several results. The results show that: Human activities have greatly interfered with the migration and dispersal of species, affecting the distribution of critical ecological reserves. The specific performance is that in the urban center area with high intensity of human activities, the number and location of the surrounding ecological corridors change significantly with the increase in the proportion of human activity resistance and the total area remains unchanged; As part of the ecological corridors, the ecological pinch points changes with the location of the corridor, and the whole area remains unchanged; The threshold range of the restoration value of ecological barrier points is reduced. The maximum value generated by the restoration of ecological barrier points is reduced, which shows that the restoration value of ecological barrier points decreases with increased human activities.

When studying the human settlement process, it is of great significance to understand the prehistoric environment, economy and society by exploring the human–land relationship and the evolution of civilization reflected by the settlement environment. This paper explores the natural and social environmental preferences of early human settlements in Xinjiang, China, from the Palaeolithic to the Bronze Age (45 ka BP–2250 a BP). Through the characteristics of settlement preferences, the distribution of settlements is accurately predicted, and the relationship between settlement preferences and the evolution of the environment and civilization is verified and discussed. We summarize the needs and conditions of early human settlement from the perspectives of the social environment and natural environment and explain the stages, consistency and differentiation of the spatial and temporal evolution of settlement preferences with the interaction of adaptation and transformation. On this basis, we discuss the logical focuses and content of early human settlement preference research. This research provides a reference for the process, representation, driving mode, and research ideas of early human settlement preferences.

Graph neural networks (GNNs) have received much attention recently because of their excellent performance on graph-based tasks. However, existing research on GNNs focuses on designing more effective models without considering much about the quality of the input data. In this paper, we propose self-enhanced GNN (SEG), which improves the quality of the input data using the outputs of existing GNN models for better performance on semi-supervised node classification. As graph data consist of both topology and node labels, we improve input data quality from both perspectives. For topology, we observe that higher classification accuracy can be achieved when the ratio of inter-class edges (connecting nodes from different classes) is low and propose topology update to remove inter-class edges and add intra-class edges. For node labels, we propose training node augmentation, which enlarges the training set using the labels predicted by existing GNN models. SEG is a general framework that can be easily combined with existing GNN models. Experimental results validate that SEG consistently improves the performance of well-known GNN models such as GCN, GAT and SGC across different datasets.

Microbial fuel cells (MFCs) are of great interest due to their capability to directly convert organic compounds to electric energy. In particular, MFCs technology showed great potential to directly harness the energy from xylose in the form of bioelectricity and biohydrogen simultaneously. Herein, we report a yeast strain of Cystobasidium slooffiae JSUX1 enabled the reduction and assembly of graphene oxide (GO) nanosheets into three-dimensional reduced GO (3D rGO) hydrogels on the surface of carbon felt (CF) anode. The autonomously self-modified 3D rGO hydrogel anode entitled the yeast-based MFCs with two times enhancement on bioelectricity and biohydrogen production from xylose. Further analysis demonstrated that the 3D rGO hydrogel attracted more yeast cells and reduced the interfacial charge transfer resistance, which was the underlying mechanism for the improvement of MFCs performance. This work offers a new strategy to reinforce the performance of yeast-based MFCs and provides a new opportunity to efficiently harvest energy from xylose.

The purpose of this study is to explore the degree and spatial distribution of dust heavy metal pollution in Tianshui City, the health risks, and the sources of heavy metals. The geoaccumulation index and health risk assessment are used to study pollution levels and human health risks, and Cu, Zn, and Pb pollution are found to be serious. The total exposure of children to dust and heavy metals is 8.329 × 10−3 mg·kg−1·d−1, which is 4.66 times that of adults. The effect of carcinogenic heavy metal exposure is more significant for adults than for children. The total non-carcinogenic risk quotient to children via multiple pathways is 2.1690, which is higher than that of adults. Children’s Pb non-carcinogenic risk quotient is 4.79 times that of adults, and children are more sensitive than adults to the health risks of Pb pollution. The GeoDetector and Unmix 6.0 models are used for source analysis, revealing that Zn, Pb, and As pollution originate primarily from urban transportation systems, V is sourced from soil-forming parent materials, and Mn, Ni, Cu, and Co arise from mixed sources. Therefore, the treatment of heavy metal pollution in cities needs to focus more on the urban transportation system.

Blockade of the programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) signalling pathway is a promising tumour immunotherapeutic approach, and small molecule drugs have more advantages than monoclonal antibody macromolecules in clinical applications. Therefore, a series of 1-methyl-1H-pyrazolo[4,3-b]pyridine derivatives as PD-1/PD-L1 interaction novel small-molecule inhibitors were designed employing a ring fusion strategy. The inhibitory activity of compounds was evaluated by the HTRF assay, among which D38 was identified as the most potent PD-1/PD-L1 interaction inhibitor with an IC50 value of 9.6 nM. Furthermore, D38 exhibited prominent inhibitory activity against the PD-1/PD-L1 interaction with an EC50 value of 1.61 μM in a coculture model of PD-L1/TCR activator-expressing CHO cells and PD-1-expressing Jurkat cells. In addition, the preliminary structure-activity relationships (SARs) of compounds were elucidated, and the binding mode of D38 with the PD-L1 dimer was analysed by molecular docking. Overall, D38 could be employed as a prospective lead compound of PD-1/PD-L1 interaction inhibitors for further development.

Palladium-catalyzed 2-substituted quinazolin-4(3

Blockade of the programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) pathway is an attractive strategy for immunotherapy. A novel series of compounds bearing a benzo[d]isothiazole scaffold were developed, among which CH20 exhibited promising activity, with an IC50 value of 8.5 nM. Further cell-based PD-1/PD-L1 blockade bioassays indicated that CH20 can inhibit the PD-1/PD-L1 interaction at the cellular level, with an EC50 value of 5.6 μM CH20 could have better potency in restoring the activity of effector cells, as the maximal luminescence values (RLUmax) of CH20 were equivalent to those of PD-L1 mAbs. The docking analysis of CH20 with the PD-L1 dimer complex (PDB ID: 6R3K ) confirmed that CH20 is a promising lead compound for the development of inhibitors of the PD-1/PD-L1 interaction. The preliminary structure-activity relationship was investigated in this paper, with the aim of future drug development.

The photocatalytic reduction of carbon dioxide on nanoparticles of group VIII transition metals represents an emerging research area in recent years because of their promise in transforming carbon dioxide, a greenhouse gas, into value-added chemicals and fuels with the energy input of light. This mini review summarizes the fundamentals of the reduction of carbon dioxide and addresses how the photoexcitation of the metal nanoparticles can influence the reactions. The important roles of non-thermal hot electrons and photothermal effect in the photocatalytic reduction of carbon dioxide are highlighted, and the recent research reported in the literature are overviewed. There are still challenges in characterizing the photocatalytic reactions to distinguish the contributions of non-thermal and photothermal effects.

Selective aerobic oxidation of primary alcohols to aldehydes at low temperature and ambient condition is essential for many value-increasing industrial processes, although the low oxidizing power of the ambient oxygen represents the major challenge to widely implement this important reaction. Herein, we report that the oxidizing power of oxygen adsorbed on quantum-sized Rh nanocubes is significantly enhanced upon photo-illumination to accelerate the oxidation reaction with a selectivity of 100%. Light absorption in the Rh nanocubes anchored on large silica spheres leads to efficient generation of hot electrons in the Rh nanocubes, which are injected into the O–O bonds adsorbed on Rh surface to cleave them into adsorbed oxygen atoms with a much higher oxidizing power. The silica (SiOx) spheres enhance both the light absorption power and colloidal stability of the small Rh nanocubes, making the Rh/SiOx hybrid particles as a unique photocatalyst to readily promote the selective aerobic oxidation of alcohols to aldehydes.

This work aims at obtaining comprehensive information on the corrosion behaviour of AA2024-T3 in oxalic acid solutions under different concentrations (0.007–0.2 M) and pH (2–6). Various tests to characterise the corrosion behaviour are performed, including weight loss and electrochemical tests. Coupon surfaces are examined using infinite-focus microscopy, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, Raman spectroscopy and diffuse reflectance infrared Fourier transform spectroscopy. Corrosion rates, anodic and cathodic reaction kinetics are detailed to provide a fundamental understanding of the electrochemical behaviour of AA2024-T3 as a function of pH and oxalate concentration. The synergistic effect of pH and oxalate concentration on corrosion of AA2024-T3 is evaluated for both AA2024-T3 matrix and main intermetallics (i.e. Al–Cu–Mg and Al–Cu–Fe–Mn) and the electrochemical behaviour of each constituent element in AA2024-T3 is systematically studied.

Polymeric microspheres (MSs) have broad applications. Poly(benzyl methacrylate) (PBzMA) have various important applications, such as optical materials, electrochromatography, and photoresists. However, previous studies on PBzMA were on fabricating bulk polymers or nano-sized (

Blocking the programmed cell death protein 1 (PD-1) and programmed death-ligand (PD-L1) interaction has emerged as one of the most promising treatments for cancer immunotherapy. A novel series of compounds bearing a benzo[d]isoxazole scaffold was developed as PD-1/PD-L1 inhibitors, among them, compound P20 exhibited the most potent inhibitory activity, with an IC50 value of 26.8 nM. The preliminary structure–activity relationship was also investigated. The docking analysis of compound P20 with the PD-L1 dimer complex (PDB ID: 5j89) indicated that compound P20 was bound to the PD-L1 dimer with high affinity. These results suggest that compound P20 is a promising lead compound for the development of inhibitors of the PD-1/PD-L1 interaction.

A range of fully biobased unsaturated polyesters (bio-UPs) derived from 2,5-furandicarboxylic (FDCA), itaconic acid (IA), succinic acid (SA), and 1,3-propanediol (PD) were obtained via direct polycondensation. The chemical structures of the bio-UPs were identified by Fourier transfrom infrared spectroscopy and 1H NMR before they were cured together with a biobased, nonvolatile reactive diluent, guaiacol methacrylate (GM). The thermal and mechanical characterizations of the cured bio-UPs were evaluated using thermogravimetric analysis, 3-point bending tests, and dynamic mechanical analysis. Results showed that the thermal properties, flexural strength, and modulus of the cured bio-UPs were greatly improved after the introduction of FDCA. The temperature of 5% thermal weight loss reached 330 °C, and the flexural strength and modulus reached 122.8 and 3521 MPa, respectively. These results indicate that the bio-UPs have the potential to replace petroleum-based UPs.

Corrosion of aluminum alloy 2024 (AA 2024-T3) exposed to fungus Aspergillus niger cultured on glucose containing potato dextrose agar was studied in a high humidity and sterile atmospheric environment. The biofilm evaluation, weight loss measurement, quantitative pit analysis and corrosion product characterization were carried out. Results showed that, under this condition, the presence of A. niger accelerated corrosion process. The corrosion rate of AA 2024-T3 by A. niger was more than 4 times of that exposed to NaCl. Also, severe pitting corrosion, comparable to AA 2024-T3 exposed to NaCl, and aluminum depletion accompanied with copper enrichment were observed. Furthermore, the corrosion morphology was found to be related to the biofilm thickness. The dominant metabolite of A. niger under our experimental condition was identified to be oxalic acid, an aggressive corrodent that causes similar corrosion rate and corroded pit morphology as those observed in this study. Therefore, oxalic acid produced by A. niger under our specific experimental condition is believe to be the main cause for the corrosion of AA 2024-T3.

The inner-product navigable small world graph (ip-NSW) represents the state-of-the-art method for approximate maximum inner product search (MIPS) and it can achieve an order of magnitude speedup over the fastest baseline. However, to date it is still unclear where its exceptional performance comes from. In this paper, we show that there is a strong norm bias in the MIPS problem, which means that the large norm items are very likely to become the result of MIPS. Then we explain the good performance of ip-NSW as matching the norm bias of the MIPS problem - large norm items have big in-degrees in the ip-NSW proximity graph and a walk on the graph spends the majority of computation on these items, thus effectively avoids unnecessary computation on small norm items. Furthermore, we propose the ip-NSW+ algorithm, which improves ip-NSW by introducing an additional angular proximity graph. Search is first conducted on the angular graph to find the angular neighbors of a query and then the MIPS neighbors of these angular neighbors are used to initialize the candidate pool for search on the inner-product proximity graph. Experiment results show that ip-NSW+ consistently and significantly outperforms ip-NSW and provides more robust performance under different data distributions., Comment: 8 pages, 8 figures

Epoxidized citric acid (ECA) is synthesized as a highly reactive bio-based compatibilizer to improve the flexural property of polylactide (PLA)/microcrystalline cellulose (MCC) blends. Confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) analysis, ECA includes three oxirane groups in its chemical structure with the rather high epoxy value at 0.76. After adding 1–5 wt % ECA in PLA/MCC blends, the interfacial adhesion between PLA and MCC is significantly improved. Accordingly, flexural strength, flexural modulus as well as impact strength of PLA/MCC/ECA blends are all improved and thus the increase of the flexural properties. This work suggests an effective way to create biobased compatibilizer with high reactivity and hereby displays a feasible way to fabricated fully bio-based PLA/MCC blends with high performance.

In this paper, three bio-based unsaturated polyesters were synthesized from itaconic acid and different diols which could be derived from renewable resources. Their chemical structures were confirmed by FT-IR, 1H NMR and acid value as well as hydroxyl value. Waterborne UV curable networks based on these polyesters were manufactured and their mechanical properties, thermal stability and coating properties including pencil hardness, flexibility, adhesion, water resistance and solvent resistance were investigated. Results showed that the UV-cured polyester coatings exhibited high hardness, good water resistance and solvent resistance. The coatings reported in this paper combined the merits of bio-based materials, UV-curing process and water distribution.

A biobased monofunctional compatibilizer (called Epicard) is first synthesized by the reaction of cardanol with epichlorohydrin as confirmed by Fourier transform infrared and 1H NMR. Subsequently, biosourced polymers, polylactide (PLA) and starch, are melt-blended by a twin-screw extruder with Epicard. Confirmed by the measurements of contact angle and 1H nuclear magnetic resonance of the extracted starches from PLA/starch/Epicard blends, the Epicard only possesses a monoepoxy group to mainly react with starch and then increased the hydrophobicity of the starches during the melt-blending process. As a result, an obvious improvement to the interfacial adhesion between starch and PLA is observed by the scanning electron microscopy. Furthermore, the tensile properties of PLA/starch blends are effectively improved with the addition of Epicard. This study suggests a simple but effective material technique by utilizing a novel plant oil modifier to increase interfacial adhesion in fabricating fully biobased PLA...