摘要 : Purpose This study examined the influence of corporate governance (CG) in relation to venture capital (VC) investment on invested firm's corporate social responsibility (CSR) performance in the Chinese context. More specifically, this paper examined the mediation of the proportion of independent directors (INDD), management shareholding (MSH) and executives' political connections (POLC) in the above-mentioned relationship. Design/methodology/approach This empirical study performed multiple mediation testing and bootstrap mediation robustness test on data from Chinese A-class shares IPO companies between 2010 and 2018. Findings The results of direct relationship analysis showed that VC support is detrimental to firm' CSR performance, consistent with previous research studies. The indirect effect analysis showed that VC reduced firm' CSR through reduction of INDD on board and increased MSH. Conversely, VC contributed to firm's CSR through higher POLC, which confirmed the significance of the joint mediation model. Practical implications This study offers stakeholders the opportunity to develop a deeper understanding of the role of VC institutions, independent directors and executives, in terms of firm's CSR, as well as provides insights on control rights allocation and policy drafting on independent directors when considering accessing VC support. Originality/value By analyzing the mediation model of the VC–CSR relationship, this paper provides evidence to enrich the debate on the role of CG in the relation between VC and firm's CSR.

摘要 : It is known that monotone recurrence relations are defined by finding equilibria of generalized Frenkel-Kontorova models. In this paper, we intend to study quasi-periodic monotone recurrence relations. By introducing a countable set consisting of integers with bounded distances and improving a method of Angenent used for studying periodic monotone recurrence relations, we derive a criterion for the existence of solutions with bounded deviations from the rigid rotation. With the help of the criterion, a range of parameters is provided to guarantee the quasi-periodic standard map has orbits with bounded deviations from the rigid rotation corresponding to each given rotation number.

摘要 : Background: As we all know, finding new pharmaceuticals requires a lot of time and money, which has compelled people to think about adopting more effective approaches to locate drugs. Researchers have made significant progress recently when it comes to using Deep Learning (DL) to create DTI. Methods: Therefore, we propose a deep learning model that applies Transformer to DTI prediction. The model uses a Transformer and Graph Transformer to extract the feature information of protein and compound molecules, respectively, and combines their respective representations to predict interactions. Results: We used Human and C.elegans, the two benchmark datasets, evaluated the proposed method in different experimental settings and compared it with the latest DL model. Conclusion: The results show that the proposed model based on DL is an effective method for the classification and recognition of DTI prediction, and its performance on the two data sets is significantly better than other DL based methods.

摘要 : Non-radical catalytic oxidation processes can eliminate refractory pollutants from wastewater containing complex substrates such as dissolved organic matter, but the production of selective non-radicals is challenging during the activation of peroxymonosulfate (PMS). Herein, a novel magnetic carbon-based catalyst (Fe 3 O 4 @CD-8, where 8 represents an annealing temperature of 800 °C) with N and Fe species as catalytic active sites was fabricated to remediate sulfamethoxazole (SMX)-containing water. It showed excellent SMX removal efficiency and facilitated singlet oxygen ( 1 O 2 ) production. The characterization results revealed that Fe 3 O 4 @CD-8 had a microscopically hierarchical pore structure and an overall core–shell-like structure. Due to its large specific surface area, N-containing species, and Fe nanoparticles, 0.1 g/L Fe 3 O 4 @CD-8 removed almost 100% SMX (24 min) and achieved a 44.1% mineralization (40 min) efficiency in the presence of 0.5 mM PMS. This catalytic system also maintained its removal performance in the presence of inorganic anions and humic acids and over a wide pH range of 3–11, showing good tolerance to various environmental factors. 1 O 2 was confirmed to be the predominant active species for SMX degradation using the Fe 3 O 4 @CD-8/PMS system. Density functional theory (DFT) calculations, intermediate monitoring, and toxicity evaluation demonstrated that SMX was transformed into low-toxicity molecules and completely mineralized into CO 2 and H 2 O. The addition of Fe nanoparticles enhanced PMS adsorption and facilitated the Fe(III)/Fe(II) redox cycle to accelerate the activation of PMS. This study provides new insights and strategies for the controlled production of non-radicals for remediating antibiotic-containing wastewater.

摘要 : Three-dimensional sponge-architecture covalent organic frameworks (COFs)-aerogel was successfully designed and synthesized via a freeze-drying template approach, and utilized as an efficient sorbent in solid-phase extraction (SPE). A method for selective enrichment of pharmaceutical contaminants including tetracycline, chlortetracycline, methacycline and oxytetracycline in the environment and food samples was proposed by combining with high performance liquid chromatography (HPLC). To understand the adsorption mechanism, selectivity test and molecular dynamics (MD) simulated calculation were both carried out. The experimental and in-silico results demonstrated that the COFs-aerogel possessed high selectivity for contaminants with H bond acceptors/donors and good efficiency with maximum adsorption capacity up to 294.1 mg/g. The SPE-based HPLC method worked well in the range of 8–1000 ng/mL, with the need of little dose of adsorbent and sample volume while no need of spectrometer, outgoing the reported adsorbents. Under the optimized conditions, the intra-day and inter-day relative standard deviations (RSD) of repeatability were within 2.78–6.29 % and 2.44–8.42 % (n = 5). The results meet the current detection requirement for practical applications, and could be extended for further design of promising adsorbents.

摘要 : G-quadruplexes (G4) have received significant attention in the field of aptasensors owing to their unique physicochemical characteristics. A dual-mode, protein-free and label-free aptamer sensor based on plasmonic colorimetry and G4 fluorescence (PC@GF-aptasensor) was proposed for ochratoxin A (OTA). Colorimetry mode was achieved through the surface plasmon resonance (SPR) effect, which related to the OTA-Apt-based G4–OTA. The fluorescence mode was reflected by the insertion of thioflavin T (ThT) into G4–OTA. The OTA could be interpreted via three readouts: (1) naked eye (LOD of 2.0 ng mL −1 ), (2) smartphone (LOD of 1.65 ng mL −1 ), and (3) spectrofluorometer (LOD of 0.93 ng mL −1 ). The PC@GF-aptasensor exhibited several advantages, such as a standardised recognition group, simplified operation, low background signal, and practicality. The proposed PC@GF-aptasensor integrated SPR-based multicolour interpretation and ThT-inserted fluorescence reflection to obtain a dual-mode optical biosensor, which may provide valuable insights for the development of other targets with G4-based aptamers.

摘要 : The DCMD technology for wastewater treatment is very promising. However, it is easily suffered by membrane fouling and wetting. In this study, a Janus membrane was fabricated by coating polyvinylamine (PVAM) and gallic acid (GA) onto one side of a PVDF composite membrane, which another side is covered with POTS-SiO 2 . The PVAM and GA side could bind water to form a hydration layer, thus repel the contaminants. The POTS-SiO 2 side was superhydrophobicity and prevented the membrane wetting. Finally, The Janus membrane presented exceptional performance in separating salt containing emulsified oil by DCMD. It kept a stable flux of 17.0 ± 0.2 Kg·m −2 ·h −1 and a low level conductivity of 0.60 ± 0.02 μS/cm in the cold side during the 36 h DCMD procedure, compared with the pristine PVDF membrane and the PVDF/POTS-SiO 2 membrane. The results presented simultaneously antifouling and antiwetting properties of the Janus membrane. While the Janus membrane can be well used in desalination of emulsified oil containing salt, it has a great potential for application to treat other complex wastewater.

摘要 : High-performance porous polyimide (PI) monoliths, including PI aerogels, sponges, and foams, have become one of the hotspots in both researching and applications due to their superior properties such as high porosity, outstanding mechanical and thermal stability, low dielectric constant and thermal conductivity. Up to now, various fabricating methods and applicating situations for PI porous monolith materials have been reported. From the viewpoint of molecular chemistry, porous structure construction, as well as the functional modification, the property optimization and adjustment are feasible, endowing PI monoliths with promising potential for different practical applications ( e.g. sensors, low-k materials, thermal management, energy field and utilization, absorption and filtration, photonic utilization, etc.). In this review, the recent progress of porous PI monoliths was summarized in detail based on the fabrication methods, functional modifications, as well as multi-functional applications. Besides, the future perspectives of this field were also provided for reference. Apart from presenting an overview of progress made in the field of PI porous monoliths, this review could also be meaningful for those researching topics which have similarity within.

摘要 : In their study of the truncation of Euler's pentagonal number theorem, Andrews and Merca introduced a partition function M k ( n ) to count the number of partitions of n in which k is the least integer that is not a part and there are more parts exceeding k than there are below k . In recent years, two conjectures concerning M k ( n ) on truncated theta series were posed by Andrews, Merca, and Yee. In this paper, we prove that the two conjectures are true for sufficiently large n whenever k is fixed.

摘要 : Using linear-stability analysis, two-dimensional modulation instability (MI) of plane wave is studied in nonlocal media with competing cubic–quintic (CQ) nonlinearities, which shows that MI can be effectively eliminated by strong nonlocality and competing quintic nonlinearity. Furthermore, propagation properties of higher-order soliton clusters, i.e., Hermite–Gaussian (HG) and Laguerre–Gaussian (LG) solitons are also investigated. Bifurcated solutions of these solitons are obtained analytically with variational approach. We also demonstrate in detail the propagation dynamics of the HG and LG solitons with split-step Fourier transform.