43 research outputs found
Spatio-temporal divergence in the responses of Finland's boreal forests to climate variables
Spring greening in boreal forest ecosystems has been widely linked to increasing temperature, but few studies have attempted to unravel the relative effects of climate variables such as maximum temperature (TMX), minimum temperature (TMN), mean temperature (TMP), precipitation (PRE) and radiation (RAD) on vegetation growth at different stages of growing season. However, clarifying these effects is fundamental to better understand the relationship between vegetation and climate change. This study investigated spatio-temporal divergence in the responses of Finland's boreal forests to climate variables using the plant phenology index (PPI) calculated based on the latest Collection V006 MODIS BRDF-corrected surface reflectance products (MCD43C4) from 2002 to 2018, and identified the dominant climate variables controlling vegetation change during the growing season (May-September) on a monthly basis. Partial least squares (PLS) regression was used to quantify the response of PPI to climate variables and distinguish the separate impacts of different variables. The study results show the dominant effects of temperature on the PPI in May and June, with TMX, TMN and TMP being the most important explanatory variables for the variation of PPI depending on the location, respectively. Meanwhile, drought had an unexpectedly positive impact on vegetation in few areas. More than 50 % of the variation of PPI could be explained by climate variables for 68.5 % of the entire forest area in May and 87.7 % in June, respectively. During July to September, the PPI variance explained by climate and corresponding spatial extent rapidly decreased. Nevertheless, the RAD was found be the most important explanatory variable to July PPI in some areas. In contrast, the PPI in August and September was insensitive to climate in almost all of the regions studied. Our study gives useful insights on quantifying and identifying the relative importance of climate variables to boreal forest, which can be used to predict the possible response of forest under future warming.Peer reviewe
Platycodon D attenuates renal ischemia-reperfusion injury in rats
Objective To investigate the protective effect of Platycodin D (PD) on renal ischemia-reperfusion injury in rats. Methods The rats were divided into sham group, model group, low, middle and high-dose groups with 10 animals in each. The rat model of ischemia reperfusion injury was established by clamping the bilateral renal pedicles in model group, low, middle and high-dose group. The rats in sham group underwent the same modeling operation but did not clamp the renal pedicles. Before 5 minutes of modeling, the rats of low, middle and high-dose group were intra-peritoneally injected with 12.5, 25 and 50 mg/kg PD, respectively. After 24 h of modeling, the serum creatinine (Cr) and blood urea nitrogen (BUN) levels, as well as antioxidant markers[superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA)] levels in kidney tissues were measured. HE staining was used to evaluate renal tissue lesions. Immuno-histochemical staining was used to detect the expression of caspase-3 in renal tissue, the apoptosis index of renal tubular epithelial cells was evaluated by the counting of caspase-3 positive cells. RT-qPCR was used to detect the expression of interleukin-1ÎČ (IL-1ÎČ), IL-6 and IL-10 mRNA in renal tissues. Western blot was used to detect the expression of Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), p65, p-p65, inhibitor of nuclear factor kappa B (NF-ÎșB) (IÎșB) and p-IÎșB. Results Compared with sham group, the kidney lesions, serum Cr and BUN levels, apoptosis index of renal tubular epithelial cells in model group were all increased (PïŒ0.05). Compared with model group, the kidney lesions, serum Cr and BUN levels, apoptosis index of renal tubular epithelial cells in low, middle and high-dose group were decreased (PïŒ0.05). Compared with sham group, the level of MDA and mRNA of IL-1ÎČ and IL-6, the protein expression of TLR4/MyD88/NF-ÎșB signaling pathway in kidney tissue in model group were all significantly increased while the level of SOD and GSH-Px and mRNA of IL-10 in rat kidney tissue were decreased(PïŒ0.05). Compared with model group, the level of MDA, mRNA of IL-1ÎČ and IL-6, the protein expression of TLR4/MyD88/NF-ÎșB signaling pathway in kidney tissue in low, middle and high-dose group were all decreased, SOD and GSH-Px and IL-10 mRNA in rat kidney tissue were increased (PïŒ0.05). Conclusions Platycodin D has a protective effect on renal ischemia-reperfusion injury in rats, and the underlying mechanism may be related to the improvement of antioxidant capacity and inhibition of TLR4/MyD88/NF-ÎșB signaling pathway
Deformation characteristics and engineering effect evaluation of a sandstone bedding excavation high slope treatment project during construction
In order to study the slope deformation law during and after the construction of the sandstone bed-cut high slope support project and the effect of the treatment project, this paper relies on a slope support project in Beijing to analyze the axial force of the anchor cable and the slope during the construction process. The slope displacement is monitored and analyzed, and the results show that the change of the axial force of the anchor cable is mainly divided into the acceleration loss stage, the fluctuation stage and the continuous stable trend stage; the change of the axial force of the anchor cable can well reflect the change of the internal force of the slope; the change of horizontal displacement and vertical settlement can reflect the change law of the deep displacement of the slope and the stability of the slope, has a better support effect. The finite element analysis software was used to simulate the excavation and support process of the sandstone-layered high slope. It was found that with the excavation of the slope, the displacement of the slope developed along the slope angle of the weak sliding surface, and the stability of the slope decreased. The monitoring results and the simulation results are compared and analyzed, and it is found that the change trends of the two are basically the same, which proves that the slope support system can effectively control the deformation of the slope. The research results can provide reference for the design and construction of similar slopes in the future
Guanxinjing capsule in the treatment of chronic stable angina: study protocol for a randomized controlled trial
Abstract Background Stable angina is a common cardiovascular disease with high mortality and a poor prognosis. Although there are various interventions against stable angina, none are able to significantly reduce the mortality rate. Guanxinjing capsule (GXJ) is made from the classical Chinese prescription Xuefuzhuyutang (èĄćșéçæ±€). Both basic research and clinical studies have shown that GXJ can relieve the symptoms of angina, but currently, the effects of GXJ lack high-quality clinical evidence. The aim of this study was to evaluate the clinical effectiveness and safety of GXJ compared with placebo. Methods/design This multicentre, blinded, randomized trial will be conducted with a total of 120 participants diagnosed with chronic stable angina (Qi deficiency and blood stasis syndrome). Using a central randomization system, participants will be randomized (1:1) into groups receiving either GXJ or placebo for 8 weeks. After a 2-week run-in period, eligible patients will receive either GXJ or placebo (4 pills, three times daily) for 8 weeks in addition to conventional treatment. The primary outcomes include changes in the total exercise time on exercise tolerance tests and changes in the integral scores of angina symptoms. The secondary outcome measures include changes in the maximal estimated workload, changes in time to a 1 mm ST-segment depression or raise, changes in the time to onset of angina during exercise tolerance testing, changes in the total score of traditional Chinese medicine syndrome, and changes in the total score of the Generalized Anxiety Disorder 7-item assessment between baseline and week 8. Other outcome measures will also be assessed. All exercise tolerance tests use a standard Bruce multistage exercise test protocol. Adverse events will be monitored throughout the trial. Discussion This study will investigate whether GXJ can alleviate clinical symptoms, increase the angina-free walking time, and improve quality of life in patients with chronic stable angina (Qi deficiency and blood stasis syndrome). The results of this study will provide clinical evidence for the application of GXJ to the treatment of stable angina. Trial registration Chinese Clinical Trial Registry, ChiCTR1800014258. Registered on 2 January 2018
CircRNA Galntl6 sponges miR-335 to ameliorate stress-induced hypertension through upregulating Lig3 in rostral ventrolateral medulla
Rostral ventrolateral medulla (RVLM) is thought to serve as a major vasomotor center that participates in controlling the progression of stress-induced hypertension (SIH). Circular RNAs (circRNAs) perform important functions in the regulation of diverse physiological and pathological processes. However, information concerning the functions of RVLM circRNAs on SIH remains limited. RNA sequencing was performed to profile circRNA expression in RVLMs from SIH rats, which were induced by electric foot shocks and noises. The functions of circRNA Galntl6 in reducing blood pressure (BP) and its potential molecular mechanisms on SIH were investigated via various experiments, such as Western blot and intra-RVLM microinjection. A total of 12,242 circRNA transcripts were identified, among which circRNA Galntl6 was dramatically downregulated in SIH rats. The upregulation of circRNA Galntl6 in RVLM effectively decreased the BP, sympathetic outflow, and neuronal excitability in SIH rats. Mechanistically, circRNA Galntl6 directly sponged microRNA-335 (miR-335) and restrained it to reduce oxidative stress. Reintroduction of miR-335 observably reversed the circRNA Galntl6-induced attenuation of oxidative stress. Furthermore, Lig3 can be a direct target of miR-335. MiR-335 inhibition substantially increased the expression of Lig3 and suppressed oxidative stress, and these favorable effects were blocked by Lig3 knockdown. CircRNA Galntl6 is a novel factor that impedes SIH development, and the circRNA Galntl6/miR-335/Lig3 axis represents one of the possible mechanisms. These findings demonstrated circRNA Galntl6 as a possibly useful target for the prevention of SIH
Cytoplasmic p27 is a novel prognostic biomarker and oncogenic protein for nasopharyngeal carcinoma
AbstractCytoplasmic p27 plays an important role in regulating the cell cycle. Recent studies have revealed p27 protein translocation from the nucleus to the cytoplasm in many tumour cells. The aim of this study was to investigate the role and molecular mechanisms of cytoplasmic p27 in the progression of nasopharyngeal carcinoma (NPC) and to explore its prognostic value. We found increased cytoplasmic p27 expression by immunohistochemistry in NPC tissues, and its expression level was significantly correlated with the T classification and TNM clinical stage of NPC. The survival rate was significantly lower for NPC patients with cytoplasmic p27 immunopositivity than for NPC patients with cytoplasmic p27 immunonegativity, and cytoplasmic p27 was an independent risk factor that affected the prognosis of patients with NPC. Cytoplasmic p27 promoted the proliferation, cell cycle progression, migration, and invasion of NPC cells, increased Bim-1 and Twist1 protein levels, and decreased RhoA-GTP level. Collectively, these findings suggest that cytoplasmic relocalization of p27 is involved in the pathogenesis of NPC and is closely related to the unfavourable prognosis of patients with NPC. Therefore, cytoplasmic p27 might be a useful prognostic factor and potential therapeutic target for patients with NPC
Characterizing differences in the phosphorus activation coefficient of three typical cropland soils and the influencing factors under long-term fertilization
<div><p>The phosphorus activation coefficient (PAC, the ratio of available P to total P) is an important indicator of soil P availability and the transformation of P fractions. Understanding the details of the PAC is useful to estimate soil available P status and to provide P management guidance. In this research, soils from five long-term (23 years) fertilization treatments in three croplands were selected to examine the relationships between the PAC and P fractions and to analyse the influencing factors. PAC was affected by both soil types and fertilization treatments. Compared to the unfertilized control (CK) treatment, long-term P application significantly increased the PAC, all of the inorganic P (Pi) fractions and most of the organic P (Po) fractions in all the three soils, particularly in chemical fertilizer combined with manure treatment (NPKM). The PAC was significantly correlated to all of the Pi fractions proportions (<i>P</i><0.05) except for Dil. HCl-Pi and Conc. HCl-Pi. Compared with CK, the chemical P and chemical P combined with manure treatments increased the ratio of total Pi fractions to total Po fractions (P<sub>it</sub>/P<sub>ot</sub>); furthermore, NPKM significantly increased the organic C (C<sub>o</sub>) content and decreased the C<sub>o</sub>/P<sub>ot</sub> ratio. Stepwise multiple regressions showed that PAC = 0.93 C<sub>o</sub>+0.69 P<sub>it</sub>/P<sub>ot</sub>-0.07 C<sub>o</sub>/P<sub>ot</sub>-0.27CaCO<sub>3</sub>-3.79 (R<sup>2</sup> = 0.924, <i>P</i><0.001). In addition, the variance partitioning analysis showed that more variance of PAC is explained by soil factors (29.53%) than by P input (0.19%) and climate (0.25%) factors. Our findings demonstrate that P application increased the PAC by changing the C<sub>o</sub> content and the proportion of P fractions. Moreover, soil factors were the most important drivers of P transformations, and NPKM was optimal for improving soil fertility in Chinese croplands.</p></div
Morphology-Controlled Synthesis of Polyphosphazene-Based Micro- and Nano-Materials and Their Application as Flame Retardants
Common flame retardants, such as halogen-based materials, are being phased-out owing to their harmful environmental and health effects. We prepared poly-(cyclotriphosphazene-co-4,4âČ-sulfonyldiphenol) (PZS) microspheres, nanotubes, capsicum-like nanotubes, and branched nanotubes as flame retardants. An increase in reaction temperature changed the morphology from nanotubes to microspheres. A PZS shape had a positive effect on the flame retardancy of polyethylene terephthalate (PET). The PZS with a capsicum-like nanotube morphology had the best flame retardancy, and the PET limiting oxygen index increased from 25.2% to 34.4%. The flame retardancy capability was followed by PZS microspheres (33.1%), branched nanotubes (32.8%), and nanotubes (32.5%). The capsicum-like nanotubes promote the formation of highly dense and continuous carbon layers, and they release a non-combustible gas (CO2). This study confirms polyphosphazene-based flame retardants as viable and environmentally-friendly alternatives to common flame retardants. It also presents a novel and facile design and synthesis of morphology-controlled nanomaterials with enhanced flame retardant properties