[An ecological stoichiometry model based on the size of Nitraria tangutorum]. / 基于白刺个体大小的生态化学计量模型.

Ecological stoichiometry provides a new method for understanding the characteristics, driving forces and mechanisms of C, N and P coupled cycles. However, there are few reports on the variation in ecological stoichiometry of plants during their growth. In this study, we fitted the total elemental mass of different module based on the size of Nitraria tangutorum, and derived the ecological stoichiometry models of different module and whole ramet by measuring the biomass and nutrient concentrations of the current-year stems in 2017, 2-year-old stems, more than 2-year-old stems, leaves, roots and layerings of N. tangutorum ramet. Our results showed that the derivation model could well reflect the changes in ecological stoichiometry during plant growth. The old stems and the layering had higher N:P and C:P, while leaves,current-year stems, and roots had lower N:P and C:P. The whole plant nutrient elements cumulative rate was P:N:C during the growth process. These results were consistent with the growth rate hypothesis and allometric theory, and provide evidence for nutrient reabsorption. This model could be used as an effective way to analyze the dynamic characteristics of elements in plant growth.

A 4-gene prognostic signature predicting survival in hepatocellular carcinoma.

OBJECTIVE: To develop an independent prognostic signature for patients with hepatocellular carcinoma (HCC). METHODS: HCC gene expression profile the cancer genome atlas-liver hepatocellular carcinoma and GSE14520 were used as discovery and test set, respectively. Differentially expressed genes (DEGs) were identified between HCC tissues and adjacent normal liver tissues. Univariate Cox proportional hazards regression analysis was performed to identify DEGs correlated with survival of HCC patients. A 4-gene-based signature was constructed based on a least absolute shrinkage and selection operator Cox penalized regression model. The predictive value of the signature was analyzed and validated. RESULTS: Two hundred sixty-three DEGs were identified between HCC and adjacent liver tissues. After univariate survival analysis, 90 DEGs were found to be significantly correlated with the overall survival (OS) of HCC patients, of which 4 genes (KPNA2, CDC20, SPP1, and TOP2A) with non-zero coefficient were used to construct a prognostic signature. The 4-gene signature was significantly associated with the age (P = 0.046), grade ( P = 0.022), and T stage ( P = 0.023) of HCC patients in the discovery set and it also significantly associated with TNM stage ( P = 0.033), and serum alpha-fetoprotein lever ( P = 0.034). Patients in the 4-gene low-risk group were associated with better OS and recurrence-free survival (RFS) than those in the high-risk group in the discovery and test set. Meanwhile, the 4-gene signature is an independent prognostic factor regarding OS and RFS in the discovery and test set. CONCLUSION: We developed a 4-gene-based signature, which could be a candidate prognostic factor for patients with HCC.

Effect of GnRHa therapy following conservative laparoscopic surgery for endometriosis on clinical pregnant rate in patients with endometriosis-associated infertility / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the impact of conservative laparoscopic surgery for endometriosis with postoperative gonadotropin-releasing hormone agonist (GnRHa) therapy on the pregnancy outcomes in patients with endometriosis-associated infertility.</p><p><b>METHODS</b>The clinical data were collected from the patients with endometriosis-associated infertility undergoing conservative laparoscopic surgery in our department between January, 2011 and December, 2016. The patients were divided into laparoscopic surgery only group (without any other treatments) and postoperative GnRha therapy group, and the pregnancy outcomes were compared between the two groups at different time points during the follow-up.</p><p><b>RESULTS</b>In cases with moderate or severe endometriosis, laparoscopic surgery with postoperative GnRha therapy was associated with a significantly higher clinical pregnancy rate than laparoscopic surgery alone (P<0.05). In patients receiving postoperative GnRha therapy, the accumulative pregnancy rates at 6, 12, 24 and 36 months after discontinuation of GnRha therapy were significantly higher than those in patients receiving laparoscopic surgery alone. The pregnancy rate following IVF-ET cycles was significantly higher than the spontaneous pregnancy rate in patients receiving conservative laparoscopic surgery alone (P<0.05), while such a difference was not found in patients with postoperative GnRHa therapy (P>0.05).</p><p><b>CONCLUSIONS</b>GnRHa therapy after conservative laparoscopic surgery can significantly increase the clinical pregnancy rate in infertile 6 months women with moderate or severe endometriosis but not in mild cases. Within 6 months following laparoscopic surgery or following discontinuation of GnRHa therapy is the optimal time window for pregnancy, and a longer time from therapy discontinuation is associated with a lower possibility of spontaneous pregnancy.</p>

[Multi-species and multi-scale patterns and species associations of sand-fixing plantations].

Taking three sand-fixing plantations Hedysarum scoparium and Calligonum mongolicum, Haloxylon ammodendron on the oasis verges in northeast Ulanbuhe desert irrigated by Huanghe River as test objects, the multi-species and multi-scale patterns and the species associations of the plantations were investigated by contiguous quadrats transects method, with the natural vegetation nearby as the control. The results showed that 74.29% of the natural vegetation was dominated by single species pattern of Artemisia ordosica, and 24. 99% was dominated by single species pattern of Nitraria tangutorum. The sand-fixing plantations gradually became close-to-natural vegetation. Compared with natural vegetation, the sand-fixing plantations had higher pattern intensity, and played important role in sand-fixing and in accelerating the regeneration and succession of natural sand-fixing plants. However, with the succession, artificially planted shrubs would decline, while natural plants would be dominant. Therefore, it should be better to make use of the native dominated species in sand-fixing engineering. Under the almost same conditions, pattern scale was highly correlated with the characters and the associations of dominated species. The species association was correlated with the patch scale and species composition, as well as the species contribution to the patch.