Numerical study of the upwelling and downwelling effects of artificial reefs along tidal cycles in the Pearl River Estuary.

Artificial reefs (ARs) are a preferred option for managers due to their distinctive hydrodynamic properties, which support a highly productive local ecosystem. However, the hydrodynamics characteristics of ARs in natural marine environments have not been conducted. Being the first to explore the spatiotemporal characteristic of flow fields around ARs along tidal cycles in marine environments, this study redefined the upwelling and downwelling of ARs, based on natural vertical velocities, and separated the upwelling into co-direction upwelling and re-direction upwelling, and the downwelling into co-direction downwelling and re-direction downwelling. This study simulated the flow field in the Wanshan ARs area of the Pearl River Estuary along the tidal cycles using the MIKE3-FM. Numerical simulations revealed that (1) co-direction upwelling and co-direction downwelling were the dominant components of the vertical flow field effects of ARs; (2) the areas sum of upwelling and downwelling were largest in the medium water column, with about 1.6 and 1.03 times as large as the bottom and surface water column, respectively, while the fluxes sum of the upwelling and downwelling were largest in bottom water column, with approximately 1.3 and 2.2 times larger than those in the middle and surface water columns; (3) the area and volume of the upwelling and downwelling gradually decreased along neap-spring tide, exhibited significantly negative correlations with current speeds; while the upwelling flux and downwelling flux gradually increased along neap-spring tide; exhibited a significantly positive correlation with current speed; (4) the effects of tide to upwelling and downwelling of AR are forced by the northward velocity of current speed, the net flux of upwelling and downwelling showed a significant positive correlation with the northward velocity of current speed (r = 0.94). These results could provide a reference for assessing the flow field effect of ARs and a guide for the configuration and management of ARs.

Effects of artificial reef and fishing moratorium on trophic structure of biological community in the Pearl River Estuary marine ranch based on stable isotopes.

Deployment of artificial reefs (ARs) has become popular technique to create new hard-bottom habitats, increase biodiversity and richness for fisheries. We compared the faunal community structure and food web structure associated with before and after fishing moratorium between ARs and non-ARs in Wanshan Island, Pearl River Estuary using stable isotope techniques. Community composition showed higher differences between ARs and non-ARs. The range of δ13C and δ15N of different functional groups can distinguish the pelagic and benthic trophic pathways of the food web in reef-or-not area before and after fishing moratorium. The isotopic niches of entire faunal, as well as individual functional groups, overlapped less between ARs and non-ARs in Wanshan Island, which makes the isotopic functional indices non-equivalent. The total convex hull area (TA) of ARs was larger than that of non-ARs, indicating that nutrient pathways of ARs were more diverse. Overall, however, these results suggest that trophic structure was convergence between ARs and non-ARs, and differences before and after fishing moratorium, possibly due to seasonal differences. Finally, it was shown that the construction of ARs had a weak effect on the restoration of fishery resources in this area, which might be related to lack of further management, or even similar community composition to non-ARs areas.

Construction and influencing factors of an early warning system for marine ranching ecological security: Experience from China's coastal areas.

Marine ranching has been widely considered as a new mode of marine fishery production. Marine ranching ecological security (MRES) is the basis and premise to ensure the sustainable utilization of marine ranching functions. In this study, an MRES early warning system was constructed based on comprehensive marine ranching ecological security index (CMRESI) and system dynamic model to reveal the main factors affecting the development of marine ranching and explore the changes in MRES under different future development scenarios in China's coastal areas from 2011 to 2035. The results showed that (1) the mean CMRESI of China was only 0.3265 and spatial heterogeneity was significant, showing a general security state; (2) coupling and coordination degree of MRES subsystems was high in Jiangsu, Fujian, Shandong, and Guangdong, and resources was a major constraint on the coordinated development of MRES in the study area (63.6%); (3) Under the ecological priority development scenario, the CMRESI will be the highest in 2035; however, 27% of MRES (in Jiangsu, Fujian, and Hainan) will continue to issue serious early warnings. This study could provide a reference for construction planning, management maintenance, and decision-making of marine ranching.

Link Prediction in Complex Networks Using Recursive Feature Elimination and Stacking Ensemble Learning.

Link prediction is an important task in the field of network analysis and modeling, and predicts missing links in current networks and new links in future networks. In order to improve the performance of link prediction, we integrate global, local, and quasi-local topological information of networks. Here, a novel stacking ensemble framework is proposed for link prediction in this paper. Our approach employs random forest-based recursive feature elimination to select relevant structural features associated with networks and constructs a two-level stacking ensemble model involving various machine learning methods for link prediction. The lower level is composed of three base classifiers, i.e., logistic regression, gradient boosting decision tree, and XGBoost, and their outputs are then integrated with an XGBoost model in the upper level. Extensive experiments were conducted on six networks. Comparison results show that the proposed method can obtain better prediction results and applicability robustness.

Osteoprotegerin/receptor activator of nuclear factor-κB ligand are involved in periodontitis-promoted vascular calcification.

The present study explored the potential role of osteoprotegerin (OPG)/receptor activator of nuclear factor-κB (RANK)/receptor activator of nuclear factor-κB ligand (RANKL) in promoting vascular calcification by periodontitis. Thirty-six male Wistar rats were randomly assigned to four groups to establish animal models as follows: the sham group (group C), vascular calcification group (group VDN), periodontitis group (group CP), and test group (group CP+VDN). After eight weeks, all the rats were sacrificed. The periodontal and vascular calcification indices were detected. Quantitative polymerase chain reaction (qPCR), immunohistochemistry, western blot analysis, and enzyme-linked immunosorbent assay (ELISA) were used to quantify OPG/RANK/RANKL expression in vascular tissue and serum. Protein expression analyses revealed the expression of OPG and RANKL in the vascular tissues of the four groups. The expression of OPG in group C was the highest, which was similar to group CP+VDN, and the expression of OPG in groups CP and VDN were lower. However, the expression of RANKL was inversely correlated with OPG, and the ratio of RANKL/OPG was also higher in groups CP and VDN than that in groups C and CP+VDN. In conclusion, OPG/RANK/RANKL may play an essential role in the promotion of vascular calcification by periodontitis. However, the expression levels of OPG and RANKL were not simply superimposed when periodontitis and vascular calcification co-existed.

Bactericidal Efficacy of Photon-Induced Photoacoustic Streaming-Erbium:Yttrium-Aluminum-Garnet Laser Combined with Irrigation Solution on Enterococcus faecalis in Curved Root Canals: An In Vitro Study.

Objective: This experiment aimed to study the bactericidal effect of photon-induced photoacoustic streaming (PIPS)-erbium:yttrium-aluminum-garnet (Er:YAG) laser on Enterococcus faecalis in curved root canals. Materials and methods: Sixty-two molars with moderately curved roots (10°-20°) and 62 molars with severely curved roots (25°-40°; one root was selected in each tooth) were assigned to group A and group B, respectively. A curved root canal model with E. faecalis infection was established. Four samples were used for sterility test, and 20 samples were used for testing if the modeling was valid. The remaining 100 samples were randomly divided into 5 subgroups (A1/A2/A3/A4/A5 and B1/B2/B3/B4/B5, n = 10) and treated as follows: A1/B1: PIPS-Er:YAG laser +5.25% sodium hypochlorite (NaOCl); A2/B2: passive ultrasonic irrigation +5.25% NaOCl; A3/B3: PIPS-Er:YAG laser+normal saline (NS); A4/B4: two-hole root canal irrigator +5.25% NaOCl; A5/B5: two-hole root canal irrigator+NS. After treatment, bacterial culture counts and scanning electron microscopic (SEM) observations were carried out for each subgroup, and the bacterial clearance rate of each subgroup was calculated. SPSS 23 software package was used for statistical analysis of the data, and a single-factor analysis of variance was used to compare the subgroups. Results: The bacterial clearance rate in group A was higher than that in group B; however, in each group, A or B, there were significant differences between the subgroups (p < 0.001) except for subgroups 1 and 2 (p > 0.05). SEM revealed that the antibacterial and smear layer removal effect of root canal in subgroups 1 and 2 was better than that in subgroups 3, 4, and 5. Conclusions: PIPS-Er:YAG can significantly enhance the bactericidal effect of NaOCl on E. faecalis in moderately and severely curved root canals.

Effect of endoplasmic reticulum stress-induced apoptosis in the role of periodontitis on vascular calcification in a rat model.

The present study aimed to investigate the mechanism(s) through which endoplasmic reticulum stress (ERS)-induced apoptosis, in the role of periodontitis, affects vascular calcification. Rat models of periodontitis, vascular calcification, periodontitis-vascular calcification, and a normal group were established. Cardiovascular tissues were obtained, and hematoxylin-eosin staining was applied to demonstrate the morphological changes in vascular tissues. Immunohistochemical staining was applied to analyze apoptosis in cardiovascular tissues. The expression levels of apoptotic factor cysteinyl aspartate specific proteinase 3 (Caspase-3), ERS-induced apoptotic factors glucose-regulated protein 78 (GRP78), 94 (GRP94), and ERS-induced apoptosis pathways Caspase-12, C/EBP homologous protein (CHOP), and c-Jun N-terminal kinase (JNK) were analyzed and compared. Hematoxylin-eosin staining revealed that the arterial layers in the normal group were structurally intact. The structural damage to the aortic wall gradually aggravated from the periodontitis group to the vascular calcification group to the combined group. The immunohistochemistry results showed Caspase-3, GRP78, GRP94, and ERS-induced apoptosis pathways in the cardiovascular tissues cells in the periodontitis group, vascular calcification group, and combined group. The Caspase-3, GRP78, GRP94, and CHOP expression levels in the combined group were significantly higher than that in the normal group (P < 0.05); however, the Capase-12 and JNK expression levels in the four groups exhibited no significant differences (P > 0.05). Apoptosis induced by ERS is involved in the effect of periodontitis on vascular calcification and might be mainly achieved through the activation of the CHOP transcription pathway.

How to balance ecosystem services and economic benefits? - A case study in the Pearl River Delta, China.

There is a significant challenge in resource management: the perceived trade-off between economic growth and ecosystem conservation. In this study, we integrate a variety of quantitative research methods and models, such as the ecosystem service value (ESV), interval parameter planning (IPP), Dyna-CLUE, and Monte Carlo methods, in an attempt to balance the ESV and economic benefits. The highest system benefits can be obtained, and uncertainty in the ecosystem assessment is considered. Taking the Pearl River Delta as the study area, the results show that when the GDP growth rate is less than 6%, the ESV in 2025 will be higher than the ESV in 2017. An interval approach (upper and lower bounds) is used. For a scenario with a 5% GDP growth rate, the ESV is RMB¥ [1.85, 20.79] × 109, which is more than the ESV of the scenario with a 9% GDP growth rate. When the GDP growth rates are 5% and 9%, the proportions of forestland are [61.5%, 61.7%] and [58%, 58.2%], respectively. Furthermore, spatialization was performed using the Dyna-CLUE model. In 2025, the simulated area of farmland is larger in some small regions with 9% GDP growth rate than it is in regions with 5% GDP growth rate, thus achieving a balance between occupation and compensation of regional farmland. By comparing ecosystem planning under different GDP growth rates, an optimized land-use allocation method can help decision makers balance system benefits and ecological risks, which can provide multiple options and specific locations for decision.