Search

This research investigates the influence of green subsidies on the green innovation of environmental service firms using multiple linear regression. It covers the years 2014 through 2020 for environmental service firms listed on the Shanghai and Shenzhen Stock Exchanges. The results demonstrate that: 1) green subsidies can encourage the green innovation of environmental service firms, and research and development (R&D) investment mediates this effect; 2) the intensity of environmental regulation moderates the relationship between R&D investment and green innovation in a negative manner; 3) in less developed regions, green subsidies are more effective for promoting green innovation. These findings may assist the government in establishing green subsidy programs and developing sensible environmental policies to promote the green development of environmental service firms.

[Display omitted] • Developing a bulk cast Al 19.25 Co 18.86 Fe 18.36 Ni 43.53 EHEA with lamellar eutectics. • The developed as-cast EHEA featuring an extraordinary strain-hardening capability. • Uncovering the deformation and fracture mechanisms at multiple length scales. • A few slip lines and lattice dislocations appearing in the hard B2 lamellae. • But dynamic microstructure refinement is identified in the ductile L1 2 lamellae. Over recent years, eutectic high-entropy alloys (EHEAs) have intrigued substantial research enthusiasms due to their good castability as well as balanced strength–ductility synergy. In this study, a bulk cast Al 19.25 Co 18.86 Fe 18.36 Ni 43.53 EHEA is developed with fine in-situ lamellar eutectics. The eutectics comprise alternating ordered face-centered-cubic (L1 2) and ordered body-centered-cubic (B2) phases with semi-coherent interfaces. The resulting microstructure resembles that of most reported as-cast EHEAs, but the B2 lamellae are devoid of nano-precipitates because of the Cr-element removal in current tailored eutectic composition. Surprisingly, the B2 lamellae still feature much higher deformation resistance than the L1 2 lamellae, so that less lattice defects are detected in the B2 lamellae until the fracture. More interestingly, in the L1 2 lamellae we identify a dynamic microstructure refinement that correlates to extraordinary strain hardening in tension. The precipitate-free EHEA consequently shows excellent tensile ductility of ∼10 % and high ultimate strength up to ∼956 MPa. [ABSTRACT FROM AUTHOR]

Purpose. To further characterize CYP3A4-transfected Caco-2 cells with regard to morphological, transport, and metabolic properties, and to evaluate a different Caco-2 cell strain transfected with both CYP3A4 and oxidoreductase (OR). Methods. Transfected Caco-2 cells, Caco-2 TC7 cells, and wild-type Caco-2 cells grown onto Millicell™were used. We determined the morphological characteristics of transfected cell monolayers using light and transmission electron microscope. We determined the transport and metabolic capabilities of the transfected cells, TC7 cells, and wild-type cells with a variety of drugs, nutrients, and marker compounds. Results. The transfected Caco-2 cells formed a tight monolayer with TEER values and mannitol transport similar to the untransfected parent cell strain (wild type). However, the transfected cells (grown onto Millicell™) reached maturity approximately 33% faster than the wild-type cells. Permeabilities of propranolol, nifedipine, testosterone, linopirdine, mannitol, and cephalexin were similar in transfected and wild-type Caco-2 cells. On the other hand, the transfected cells of early passages were much more metabolically active, and metabolized standard CYP3A4 substrates (e.g., testosterone and nifedipine) as much as 100 times faster than untransfected cells. In addition, metabolism of standard substrates was inhibitable by ketoconazole and TAO. Using comparable data, the transfected cells metabolized testosterone the fastest, followed by linopirdine and nifedipine (approximate ratio: 10:6:2). The metabolites of standard substrates were generally preferably excreted to the apical membrane. Conclusions. The monolayers of newly transfected cells (CYP3A4 + OR) have a significantly increased level of CYP3A4 activities compared to untransfected cells. These cell monolayers also have desirable morphological and transport characteristics that are similar to untransfected cells.

The purpose of this study was to determine the intestinal absorption characteristics of AG337, a mechanism-based inhibitor of thymidylate synthase, using a perfused rat intestinal model. Effects of site, pH, temperature, concentration, Na⁺, and inhibitors on the absorption of AG337 were determined, after the compound was shown to be stable in buffers of various pH, blank perfusate, and intestinal homogenate. The results indicated that absorption of AG337 was temperature-, pH-, Na⁺-, concentration-, and site-dependent. The best site of absorption is duodenum, where the absorption was 3–10 times (p < 0.05) higher than absorption at jejunum, ileum, and colon. Among the four pH's studied, the best was at pH 6.5 (p < 0.05). Absorption was 80% lower in the absence of Na⁺, and 75% lower when the temperature of the perfusate was decreased to 4 °C. Permeability of AG337 also decreased about 75% when the concentration was raised to 100 µM. These results suggest that a nutrient carrier may be involved in the transport of AG337. To determine the carrier responsible for the absorption of AG337, its absorption was determined in the presence of various inhibitors at different concentrations. The results indicated that transport of AG337 was inhibited significantly (p < 0.01) by 100 µM of adenine, hypoxanthine, and xanthine. The transport was also inhibited significantly (p < 0.01) by a mixture of 100 µM each of adenine, hypoxanthine, and xanthine, but not by a mixture of 100 µM each of thymine and uracil. A higher concentration of hypoxanthine resulted in increased inhibition. In contrast, prototypical inhibitors of nucleoside transporter, dipyridamole and nitroben-zylthioinosine (NBMPR), did not significantly decrease the transport of AG337. The results also showed that absorption of AG337 had a significant nonsaturable component, with a nonsaturable Pw of 0.8. In conclusion, absorption of AG337 in the rat intestine has been shown to be mainly via a purine base carrier with a significant nonsaturable component.

The purpose of this study was to determine the intestinal absorption characteristics of AG337, a mechanism-based inhibitor of thymidylate synthase, using a perfused rat intestinal model. Effects of site, pH, temperature, concentration, Na+, and inhibitors on the absorption of AG337 were determined, after the compound was shown to be stable in buffers of various pH, blank perfusate, and intestinal homogenate. The results indicated that absorption of AG337 was temperature-, pH-, Na+-, concentration-, and site-dependent. The best site of absorption is duodenum, where the absorption was 3-10 times (p < 0.05) higher than absorption at jejunum, ileum, and colon. Among the four pH's studied, the best was at pH6.5 (p < 0.05). Absorption was 80% lower in the absence of Na+, and 75% lower when the temperature of the perfusate was decreased to 4°C. Permeability of AG337 also decreased about 75% when the concentration was raised to 100μM. These results suggest that a nutrient carrier may be involved in the transport of AG337. To determine the carrier responsible for the absorption of AG337, its absorption was determined in the presence of various inhibitors at different concentrations. The results indicated that transport of AG337 was inhibited significantly (p< 0.01) by 100μM of adenine, hypoxanthine, and xanthine. The transport was also inhibited significantly (p < 0.01) by a mixture of 100μM each of adenine, hypoxanthine, and xanthine, but not by a mixture of 100μM each of thymine and uracil. A higher concentration of hypoxanthine resulted in increased inhibition. In contrast, prototypical inhibitors of nucleoside transporter, dipyridamole and nitrobenzylthioinosine (NBMPR), did not significantly decrease the transport of AG337. The results also showed that absorption of AG337 had a significant nonsaturable component, with a nonsaturable Pwof 0.8. In conclusion, absorption of AG337 in the rat intestine has been shown to be mainly via a purine base carrier with a significant nonsaturable component.

Peptide transport and prolidase activities were measured to determine whether the expression of these two components of protein nutrition are coordinately regulated; i.e., whether an increase in the peptide transporter function will necessarily lead to a higher prolidase activity, or vice versa. The results indicated that peptide transporter function and prolidase activity respond differently to cell differentiation and feeding schedules. The results also indicated that peptide transport and prolidase activities were different in two Caco-2 cell "clones", with S-K cells transported peptides at higher rates but had lower total prolidase activities, when compared to ATCC cells. These results suggest that the expression of the peptide transporter function and prolidase activity is not coordinated. In addition, both the transporter and the prolidase activities affected the overall transport of Phe when given as the dipeptide Phe-Pro, supporting the notion that intestinal absorption of peptides is an essential component of amino acid absorption. In conclusion, the evidence suggests that the peptide transporter function and prolidase activity are not coordinately expressed by the human intestinal Caco-2 cells.