Accelerated organic matter decomposition in thermokarst lakes upon carbon and phosphorus inputs

Mineralization of dissolved organic matter (DOM) in thermokarst lakes plays a non-negligible role in the permafrost carbon (C) cycle, but remains poorly understood due to its complex interactions with external C and nutrient inputs (i.e., aquatic priming and nutrient effects). Based on large-scale lake sampling and laboratory incubations, in combination with ¹³C-stable-isotope labeling, optical spectroscopy, and high-throughput sequencing, we examined large-scale patterns and dominant drivers of priming and nutrient effects of DOM biodegradation across 30 thermokarst lakes along a 1100-km transect on the Tibetan Plateau. We observed that labile C and phosphorus (P) rather than nitrogen (N) inputs stimulated DOM biodegradation, with the priming and P effects being 172% and 451% over unamended control, respectively. We also detected significant interactive effects of labile C and nutrient supply on DOM biodegradation, with the combined labile C and nutrient additions inducing stronger microbial mineralization than C or nutrient treatment alone, illustrating that microbial activity in alpine thermokarst lakes is co-limited by both C and nutrients. We further found that the aquatic priming was mainly driven by DOM quality, with the priming intensity increasing with DOM recalcitrance, reflecting the limitation of external C as energy sources for microbial activity. Greater priming intensity was also associated with higher community-level ribosomal RNA gene operon (rrn) copy number and bacterial diversity as well as increased background soluble reactive P concentration. In contrast, the P effect decreased with DOM recalcitrance as well as with background soluble reactive P and ammonium concentrations, revealing the declining importance of P availability in mediating DOM biodegradation with enhanced C limitation but reduced nutrient limitation. Overall, the stimulation of external C and P inputs on DOM biodegradation in thermokarst lakes would amplify C-climate feedback in this alpine permafrost region.     

Oriented Transformation of Co‐LDH into 2D/3D ZIF‐67 to Achieve Co–N–C Hybrids for Efficient Overall Water Splitting

Construction of well‐defined metal–organic framework precursor is vital to derive highly efficient transition metal–carbon‐based electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in water splitting. Herein, a novel strategy involving an in situ transformation of ultrathin cobalt layered double hydroxide into 2D cobalt zeolitic imidazolate framework (ZIF‐67) nanosheets grafted with 3D ZIF‐67 polyhedra supported on the surface of carbon cloth (2D/3D ZIF‐67@CC) precursor is proposed. After a low‐temperature pyrolysis, this precursor can be further converted into hybrid composites composed of ultrafine cobalt nanoparticles embedded within 2D N‐doped carbon nanosheets and 3D N‐doped hollow carbon polyhedra (Co@N‐CS/N‐HCP@CC). Experimental and density functional theory calculations results indicate that such composites have the advantages of a large number of accessible active sites, accelerated charge/mass transfer ability, the synergistic effect of components as well as an optimal water adsorption energy change. As a result, the obtained Co@N‐CS/N‐HCP@CC catalyst requires overpotentials of only 66 and 248 mV to reach a current density of 10 mA cm^?2 for HER and OER in 1.0 m KOH, respectively. Remarkably, it enables an alkali‐electrolyzer with a current density of 10 mA cm^?2 at a low cell voltage of 1.545 V, superior to that of the IrO₂@CC||Pt/C@CC couple (1.592 V).     

Establishment of Nature Reserves in Administrative Regions of Mainland China

Nature reserves are widely considered as one available strategy for protecting biodiversity, which is threatened by habitat fragmentation, and wildlife extinction. The Chinese government has established a goal of protecting 15% of its land area by 2015. We quantitated the characteristics and distribution of nature reserves in mainland China and evaluated the expansion process for national nature reserves. National nature reserves occupy 64.15% of the total area of nature reserves. Steppe and meadow ecosystem, ocean and seacoast ecosystem, and wild plant nature reserves represent lower percentages, particularly in national nature reserves, in which they comprised 0.76%, 0.54%, and 0.69%, respectively, of the area. Furthermore, medium and small nature reserves compose 92.32% of all nature reserves. The land area under any legal protection has reached 14.80%, although only 9.78% is strictly protected. However, if 9 super-large national nature reserves, located in Southwest and Northwest China were removed, the percentage of strictly protected area decreases to 2.66% of the land area of China. The areas contained in nature reserves in each province are not proportional to the areas of the provinces, particularly for national nature reserves, with higher protection rates in Southwest and Northwest China than in other regions. Of the 31 provinces, 22 provinces feature strict protection of less than 4% of their areas by national nature reserves; these provinces are mainly located in East, Central, South, and North China. Moreover, the unevenness indexes of the distribution of nature reserves and national nature reserves are 0.39 and 0.58, respectively. The construction of nature reserves has entered a steady development stage after a period of rapid expansion in mainland China. In recent years, the total area of national nature reserves has increased slowly, while the total area of nature reserves has not increased, although the number of nature reserves continues increase.     

Randomized Adjuvant Chemotherapy of EGFR-Mutated Non-Small Cell Lung Cancer Patients with or without Icotinib Consolidation Therapy

Background

Epidermal growth factor receptor (EGFR) mutations occur in up to 50% of Asian patients with non-small cell lung cancer (NSCLC). Treatment of advanced NSCLC patients with EGFR-tyrosine kinase inhibitor (EGFR-TKI) confers a significant survival benefit. This study assessed the efficacy and safety of chemotherapy with or without icotinib in patients undergoing resection of stage IB to ⅢA EGFR-mutated NSCLC.

Methods

Patients with surgically resected stage IB (with high risk factors) to ⅢA EGFR-mutated NSCLC were randomly assigned (1:1) to one of two treatment plans. One group received four cycles of platinum-based doublet chemotherapy every three weeks, and the other group received platinum-based chemotherapy supplemented with consolidation therapy of orally administered icotinib (125 mg thrice daily) two weeks after chemotherapy. The icotinib treatment continued for four to eight months, or until the occurrence of disease relapse, metastasis or unacceptable icotinib or chemotherapy toxicity. The primary endpoint was disease-free survival (DFS).

Results

41 patients were enrolled between Feb 9, 2011 and Dec 17, 2012. 21 patients were assigned to the combined chemotherapy plus icotinib treatment group, while 20 patients received chemotherapy only. DFS at 12 months was 100% for icotinib-treated patients and 88.9% for chemotherapy-only patients (p = 0. 122). At 18 months DFS for icotinib-treated vs. chemotherapy-only patients was 95.2% vs. 83.3% (p = 0. 225), respectively, and at 24 months DFS was 90.5% vs. 66.7% (p = 0. 066). The adverse chemotherapy effects predominantly presented as gastrointestinal reactions and marrow suppression, and there was no significant difference between the two treatment groups. Patients in the chemotherapy plus icotinib treatment group showed favorable tolerance to oral icotinib.

Conclusions

The results suggest that chemotherapy plus orally icotinib displayed better DFS compared with chemotherapy only, yet the difference in DFS was not significant. We would think the preliminary result here was promising, and further trials with larger sample sizes might confirm the efficiency of adjuvant TKI in selected patients.

Trial Registration

ClinicalTrials.gov NCT02430974     

Isolation and characterization of an antimicrobial peptide from bovine hemoglobin ��-subunit

In this study, a novel 18-residue linear antimicrobial peptide derived from the central part of the bovine hemoglobin ??-subunit was identified. The peptide was purified by a combination of cationic exchange and reversed-phase high-performance liquid chromatography. The sequence was determined to be VNFKLLSHSLLVTLASHL. The theoretical molecular weight of this peptide was calculated to be 1992.38 Da, which is the same as that determined (1992.401 Da) by matrix-assisted laser desorption ionization mass spectrometry. Sequence analysis showed that there is a high degree of homology in this peptide among hemoglobin ??-subunits of bovine, sheep, deer, porcine, and human. In a radial-diffusion plate assay, this purified peptide exhibited antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans.     

Knockdown of ribosomal protein S7 causes developmental abnormalities via p53 dependent and independent pathways in zebrafish

Ribosomal proteins (RPs), structural components of the ribosome involved in protein synthesis, are of significant importance in all organisms. Previous studies have suggested that some RPs may have other functions in addition to assembly of the ribosome. The small ribosomal subunits RPS7, has been reported to modulate the mdm2-p53 interaction. To further investigate the biological functions of RPS7, we used morpholino antisense oligonucleotides (MO) to specifically knockdown RPS7 in zebrafish. In RPS7-deficient embryos, p53 was activated, and its downstream target genes and biological events were induced, including apoptosis and cell cycle arrest. Hematopoiesis was also impaired seriously in RPS7-deficient embryos, which was confirmed by the hemoglobin O-dianisidine staining of blood cells, and the expression of scl, gata1 and α-E1 globin were abnormal. The matrix metalloproteinase (mmp) family genes were also activated in RPS7 morphants, indicating that improper cell migration might also cause development defects. Furthermore, simultaneously knockdown of the p53 protein by co-injecting a p53 MO could partially reverse the abnormal phenotype in the morphants. These results strengthen the hypothesis that specific ribosomal proteins regulate p53 and that their deficiency affects hematopoiesis. Moreover, our data implicate that RPS7 is a regulator of matrix metalloproteinase (mmp) family in zebrafish system. These specific functions of RPS7 may provide helpful clues to study the roles of RPs in human disease.     

向日葵花盘功能成分及研究现状

向日葵(Helianthus annuus L.)作为我国重要的油料作物之一,其葵花籽油的提取已经实现工业化生产,但其副产物向日葵盘、秸秆、葵花籽壳和饼粕等仍然利用不足.随着技术设备条件的优化及产业化条件的成熟,向日葵副产物具有十分广阔的开发应用前景.本文对向日葵花盘现阶段的综合利用情况进行介绍,并总结了向日葵花盘中绿原酸、水溶性多糖、萜类化合物等重要活性物质的提取方法.针对我国目前面临的向日葵作物综合利用发展中出现的向日葵花盘副产物处理难问题,阐述了向日葵花盘的药用价值及其重新开发和综合利用的方法,为向日葵花盘的利用提供指导.