In view of the serious environmental pollution, which is the greatest problem the world is facing, and the continuous consumption of raw materials, it is imminent to search for green and sustainable resources. Lignin is an organic polymer that exists widely in nature, and if it can be transformed from traditional low-value waste product with low range of applications to functional materials with high application prospects, it can be of great significance to alleviate environmental pollution and shortage of fossil resources. One of the functional applications of lignin involves its use to fabricate composite with other polymeric materials, which can then be used to prepare membrane materials. This review summarizes the recent research and application progress of combining lignin with polypropylene, polyvinyl alcohol, starch, cellulose, chitosan, and other polymeric materials to prepare composite membranes; and summarizes the future development direction of lignin-based composite membranes. We hope this review may provide a new perspective to the understanding of lignin-based composite membranes and a useful reference for future research.
This study provides an estimation of the eco-compensation requirements for forest ecosystem conservation in Hainan province of China using the ecological location quotient (ELQ). It determines that the ecosystem services provided by the forest ecosystem need to be classified into predominant, secondary and potential types. Consequently, the appropriate levels of payment are calculated using the ecological valuation coefficient (EVC) method. The mechanisms and standards of payment are then determined for the corresponding stages in the context of the eco-compensation concept. In this way, guidelines are provided for practising eco-compensation, not only in Hainan province but also in the other parts of China.
The modular inner branched stent-graft (MIBSG), a novel interventional therapy, has demonstrated good effects in the endovascular treatment of aortic arch pathologies, especially those involving the supra-aortic branches. Nevertheless, the long-term efficacy of the MIBSG and in-depth quantitative evaluation of postoperative outcomes remain to be examined. Moreover, the regularity of postoperative vascular remodeling induced by MIBSG implantation has yet to be explored. To address these questions, we constructed four models (normal, preoperative, 1 week postoperative, and 6 months postoperative) based on a single patient case to perform computational fluid dynamics simulations. The morphological and hemodynamic characteristics, including the velocity profile, flow rate distribution, and hemodynamic parameter distribution (wall shear stress and its derivative parameters), were investigated. After MIBSG implantation, the morphology of the supra-aortic branches changed significantly, and the branch point moved forward to the proximal ascending aorta. Moreover, the curvature radius of the aortic arch axis continued to change. These changes in morphology altered the characteristics of the flow field and wall shear stress distribution. As a result, the local forces exerted on the vessel wall by the blood led to vessel remodeling. This study provides insight into the vascular remodeling process after MIBSG implantation, which occurs as a result of the interplay between vascular morphological characteristics and blood flow characteristics.
10 February 2024 in Research on Chemical Intermediates
With the rapid development of economy and society and the rapid advancement of industrialization and urbanization, the sewage discharged in the daily life of urban residents and the wastewater produced by industrial enterprises contain a large number of organic pollutants. Such organic pollutants are easy to flow into urban rivers through surface water, causing serious pollution of water environment, and thus adversely affecting the sustainable green development of cities. In recent years, the degradation of rhodamine B (Rh B) wastewater has become the focus of research on the treatment of refractory organic wastewater. In this paper, alkaline lignin was used as the precursor, and CQDs with fluorescence effect were prepared from bottom to top by hydrothermal method; Bi2WO6 was combined with Bi2WO6, and Bi2WO6/CQDs composite material was prepared to degrade organic pollutants into low-toxicity or non-toxic small molecules, as an effective way to solve the pollution of solar energy resources and environment. Carbon quantum dots (CQDs) have the advantages of excellent electron conduction and optical properties, non-toxicity and good biocompatibility, which will be more conducive to improving the light utilization rate of Bi2WO6 and inhibiting the recombination of electrons and holes, so as to improve its photocatalytic performance. The composite materials were characterized by XRD, FT-IR, TEM, and UV–Vis, and the results confirmed the successful preparation of Bi2WO6/CQDs using a simple hydrothermal method. The introduction of CQDs can reduce the bandgap width of Bi2WO6, thereby improving the absorption of light and promoting photogenerated electron transfer. Under visible light irradiation (300-W xenon lamp, λ > 420 nm), the amount of CQDs was 30 ml, and the degradation rate of Rh B was 86.96% within 120 min. Due to the excellent upconversion photoluminescence, as well as the photoinduced electron transfer and reservoir properties of CQDs, the Bi2WO6/CQDs composite exhibited superior photocatalytic performance in the degradation of Rh B under the irradiation of simulated solar light. This study provides a strategy for the development of high-performance catalysts based on CQDs.
Background: Moderate renal artery stenosis (50–70%) may lead to uncontrolled hypertension and eventually cause irreversible damage to renal function. However, the clinical criteria for interventional treatment are still ambiguous in this condition. This study investigated the impact of the position and degree of renal artery stenosis on hemodynamics near the renal artery to assess the short-term and long-term risks associated with this disease. Methods: Calculation models with different degrees of stenosis (50%, 60%, and 70%) located at different positions in the right renal artery were established based on the computed tomography angiography (CTA) of a personalized case. And computational fluid dynamics (CFD) was used to analyze hemodynamic surroundings near the renal artery. Results: As the degree of stenosis increases and the stenosis position is far away from the aorta, there is a decrease in renal perfusion. An analysis of the wall shear stress (WSS)-related parameters indicated areas near the renal artery (downstream of the stenosis and the entrance of the right renal artery) with potential long-term risks of thrombosis and inflammation. Conclusion: The position and degree of stenosis play a significant role in judging short-term risks associated with renal perfusion. Moreover, clinicians should consider not only short-term risks but also independent long-term risk factors, such as certain regions of 50% stenosis with adequate renal perfusion may necessitate prompt intervention.