Contrasting impacts of fertilization on topsoil and subsoil greenhouse gas fluxes in a thinned Chinese fir plantation.

Globally, forest soils are considered as important sources and sinks of greenhouse gases (GHGs). However, most studies on forest soil GHG fluxes are confined to the topsoils (above 20 cm soil depths), with only very limited information being available regarding these fluxes in the subsoils (below 20 cm soil depths), especially in managed forests. This limits deeper understanding of the relative contributions of different soil depths to GHG fluxes and global warming potential (GWP). Here, we used a concentration gradient-based method to comprehensively investigate the effects of thinning intensity (15% vs. 35%) and nutrient addition (no fertilizer vs. NPK fertilizers) on soil GHG fluxes from the 0-40 cm soil layers at 10 cm depth intervals in a Chinese fir (Cunninghamia lanceolata) plantation. Results showed that forest soils were the sources of CO2 and N2O, but the sinks of CH4. Soil GHG fluxes decreased with increasing soil depth, with the 0-20 cm soil layers identified as the dominant producers of CO2 and N2O and consumers of CH4. Thinning intensity did not significantly affect soil GHG fluxes. However, fertilization significantly increased CO2 and N2O emissions and CH4 uptake at 0-20 cm soil layers, but decreased them at 20-40 cm soil layers. This is because fertilization alleviated microbial N limitation and decreased water filled pore space (WFPS) in topsoils, while it increased WFPS in subsoils, ultimately suggesting that soil WFPS and N availability (especially NH4+-N) were the predominant regulators of GHG fluxes along soil profiles. Generally, there were positive interactive effects of thinning and fertilization on soil GHG fluxes. Moreover, the 35% thinning intensity without fertilization had the lowest GWP among all treatments. Overall, our results suggest that fertilization may not only cause depth-dependent effects on GHG fluxes within soil profiles, but also impede efforts to mitigate climate change by promoting GHG emissions in managed forest plantations.

Biomechanical study of two-level oblique lumbar interbody fusion with different types of lateral instrumentation: a finite element analysis.

Objective: The aim of this study was to verify the biomechanical properties of a newly designed angulated lateral plate (mini-LP) suited for two-level oblique lumbar interbody fusion (OLIF). The mini-LP is placed through the lateral ante-psoas surgical corridor, which reduces the operative time and complications associated with prolonged anesthesia and placement in the prone position. Methods: A three-dimensional nonlinear finite element (FE) model of an intact L1-L5 lumbar spine was constructed and validated. The intact model was modified to generate a two-level OLIF surgery model augmented with three types of lateral fixation (stand-alone, SA; lateral rod screw, LRS; miniature lateral plate, mini-LP); the operative segments were L2-L3 and L3-L4. By applying a 500 N follower load and 7.5 Nm directional moment (flexion-extension, lateral bending, and axial rotation), all models were used to simulate human spine movement. Then, we extracted the range of motion (ROM), peak contact force of the bony endplate (PCFBE), peak equivalent stress of the cage (PESC), peak equivalent stress of fixation (PESF), and stress contour plots. Results: When compared with the intact model, the SA model achieved the least reduction in ROM to surgical segments in all motions. The ROM of the mini-LP model was slightly smaller than that of the LRS model. There were no significant differences in surgical segments (L1-L2, L4-L5) between all surgical models and the intact model. The PCFBE and PESC of the LRS and the mini-LP fixation models were lower than those of the SA model. However, the differences in PCFBE or PESC between the LRS- and mini-LP-based models were not significant. The fixation stress of the LRS- and mini-LP-based models was significantly lower than the yield strength under all loading conditions. In addition, the variances in the PESF in the LRS- and mini-LP-based models were not obvious. Conclusion: Our biomechanical FE analysis indicated that LRS or mini-LP fixation can both provide adequate biomechanical stability for two-level OLIF through a single incision. The newly designed mini-LP model seemed to be superior in installation convenience, and equally good outcomes were achieved with both LRS and mini-LP for two-level OLIF.

Evolution and Simulation of Terrestrial Ecosystem Carbon Storage and Sustainability Assessment in Karst Areas: A Case Study of Guizhou Province.

Against the background of "carbon neutrality" and sustainable development goals, it is of great significance to assess the carbon storage changes and sustainability of terrestrial ecosystems in order to maintain the coordinated sustainable development of regional ecological economies and the balance of terrestrial ecosystems. In this study, the terrestrial ecosystem carbon storage in Guizhou from 2010 to 2020 was assessed with the InVEST model. Using the PLUS model, the distribution of terrestrial ecosystem carbon storage by 2030 and 2050 was predicted. The current sustainable development level of the terrestrial ecosystem of Guizhou was evaluated after establishing an index system based on SDGs. The results showed the following: (1) From 2010 to 2020, the terrestrial ecosystem carbon storage decreased by 1106.68 × 104 Mg. The area and carbon storage of the forest and farmland ecosystems decreased while the area and carbon storage of the grassland and settlement ecosystems increased. (2) Compared with 2020, the terrestrial ecosystem carbon storage will be reduced by 4091.43 × 104 Mg by 2030. Compared with 2030, the terrestrial ecosystem carbon storage will continue to decrease by 3833.25 × 104 Mg by 2050. (3) In 2020, the average score of the sustainable development of the terrestrial ecosystem was 0.4300. Zunyi City had the highest sustainable development score of 0.6255, and Anshun had the lowest sustainable development score of 0.3236. Overall, the sustainable development of the terrestrial ecosystem of Guizhou was found to be high in the north, low in the south, high in the east, and low in the west. The sustainable regional development of the terrestrial ecosystem of Guizhou was found to be unbalanced, and the carbon storage of the terrestrial ecosystem will keep decreasing in the future. In order to improve the sustainable development capacity of the terrestrial ecosystem, the government needs to take certain measures, such as returning farmland to forests and grasslands, curbing soil erosion, and actively supervising.

GDI2 is a novel diagnostic and prognostic biomarker in hepatocellular carcinoma.

BACKGROUND: GDP Dissociation inhibitor 2 (GDI2) gene has been correlated with some important biological processes in a variety of cancers, whereas the role of GDI2 in hepatocellular carcinoma (HCC) is ill-defined. We aimed to demonstrate the relationship between GDI2 and HCC based on The Cancer Genome Atlas (TCGA) data mining. METHODS: The expression of GDI2 was compared between cancer and normal tissues of 371 HCC patients collected from TCGA-LIHC, and verified in HCC cell lines. Gene set enrichment analysis (GSEA) was applied to annotate biological function of GDI2. Furthermore, Wilcoxon rank sum test, Logistics regression, as well as Cox regression and Kaplan-Meier survival analysis, were employed to evaluate the association of GDI2 expression with clinicopathological characteristics, and survival status of HCC patients, respectively. RESULTS: It showed that the expression of GDI2 was much higher in tumor tissues than in normal tissues (P < 0.001) of HCC patients. And the elevated expression of GDI2 was correlated with more aggressive HCC tumor status, including severe primary tumor extent, advanced pathological stage, serious histologic grade, and mutated TP53 status (P < 0.05). Moreover, high GDI2 expression was strongly associated with a poor survival rate (P < 0.001). Both enrichment and immune infiltration analyses implied that GDI2-associated signaling mainly involve lipid metabolism and extracellular matrix (ECM) constructing pathways related to tumor microenvironment (TME) (P < 0.05). CONCLUSIONS: The elevated expression of GDI2 predicts poor prognosis in HCC patients, indicating that GDI2 could be applied as a predictive biomarker for diagnosis and prognosis of HCC.

Exogenous Vitamin C-Triggered Surface Charge Conversion of pH/Reduction-Responsive Micelles for the Enhanced Tumor-Specific Activity of Loaded Doxorubicin.

The effective accumulation at tumor sites and endocytosis by tumor cells for anticancer agents in carriers are essential in successful cancer therapy, and both of the processes are affected by the surface charge of drug carriers. In this study, vitamin C (VC) was employed as an "exogenous switch" to trigger the surface charge conversion of DOX-loaded micelles to obtain a better antitumor effect. T micelles formed by poly(ε-caprolactone)-b-poly(N,N-diethylaminoethyl methacrylate)-ss-b-poly(2-methacryloyloxyethyl phosphorylcholine) (PCL-PDEA-ss-PMPC) turned their ζ potentials from +1 mV to +18 mV under treatment of 20 mM VC, while the ζ potentials of control R micelles formed by PCL-ss-P(DEA-r-MPC) almost remained unchanged under the same condition. DOX-loaded T@DOX and R@DOX had high DLCs of 12% and 13.8%, respectively, and both showed an accelerated drug release in a reductive environment (10 mM GSH or 20 mM VC) at pH 5.0. Notably, due to the surface charge conversion and fast drug release triggered by VC, T@DOX/VC (T@DOX was pretreated by VC) showed an enhanced cytotoxicity and cellular uptake superior to T@DOX, R@DOX, and R@DOX/VC. T@DOX/VC also displayed the in vivo antitumor effect well, which was comparable to DOX·HCl but with less toxic side effects than DOX·HCl. In summary, VC as an exogenous trigger can induce a better antitumor effect of drug-loaded micelles with a suitable polymer structure by charge conversion, and T@DOX/VC has shown to be as a promising approach to achieve potent treatment of tumors.

pH/redox dual-responsive amphiphilic zwitterionic polymers with a precisely controlled structure as anti-cancer drug carriers.

Responding to the tumor microenvironment, functional polymers can serve as preeminent drug carriers for targeted cancer therapy. Stimuli-responsive polymeric drug carriers are reported with diverse anti-tumor effects for various polymer structures. Thus, three pH/redox dual-responsive amphiphilic zwitterionic polymer 'isomers' with different locations of pH/redox responsive units were prepared to understand the relationship between polymer structure and anti-tumor effect. Containing poly(ε-caprolactone) (PCL), poly(N,N-diethylaminoethyl methacrylate) (PDEA) and poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), polymers PCL-ss-P(DEA-r-MPC) (SDRM), PCL-ss-PDEA-b-PMPC (SDBM) and PCL-PDEA-ss-PMPC (DSM) with a precisely controlled structure were constructed and confirmed through NMR, FITR and EA. The formed micellar drug carriers were characterized by their morphology, loading capacity, acid/redox sensitivity, drug release, in vitro cytotoxicity and in vivo antitumor effects. Micelles with uniform spherical morphologies can effectively encapsulate anti-tumor drugs such as DOX. Among these micelles, DSM@DOX displays the most excellent drug encapsulation capacity (13.4%) with neutral surface charge (-1.02 mV) and good stability, and is different from SDRM@DOX with positive charge (+11.1 mV) and SDBM@DOX with poor stability. All micelles respond to acid and reducing environments and present fast drug release at mildly acidic pH and high concentrations of GSH, exhibiting low burst release under the physiological conditions of plasma. There is no significant difference between these micelles in tumor cell cytotoxicity against MCF-7 and 4T1 cells. Internalization of SDRM@DOX and DSM@DOX by the tumor cells is stronger than that of SDBM@DOX. Notably, DSM@DOX has longer blood circulation and more effective accumulation at the tumor site than the other two micelles. As a result, DSM@DOX shows enhanced antitumor efficacy in 4T1 tumor-bearing mice with reduced side toxicities. Overall, structures of the above polymers significantly influence the in vivo antitumor effects of the drug carriers through blood circulation and cellular uptake.