Litterfall production and nutrient return in different-aged Chinese fir(Cunninghamia lanceolata) plantations in South China

The amounts of litter produced and nutrients returned play a fundamental role in the productivity and biogeochemical and nutrient cycling of forest ecosystems.We monitored annual litterfall production, nutrient return,and monthly dynamics over a one-year period in Chinese fir plantations aged 10, 22, and 34 years. Our objective was to quantify litterfall and nutrient return over a complete harvest rotation of Chinese fir. Annual litterfall production increased with stand age and was recorded as（3,294.6 ± 360.4）,（3,733.9 ± 211.2）, and（4,876.1 ± 212.8） kg ha-1a-1in stands aged 10, 22 and 34 years, respectively. Total litter production was significantly greater in the stand aged34 years than in the stand aged 10 years（p ／ 0.05）. With the exception of miscellaneous components, needle litterfall constituted the highest proportion（27.5–43.6 %）, followed by branches/twigs（9.5–16.6 %）. In all three plantations,annual total nutrient return to soil was in the order of C（1,119.95–2,709.05 kg ha-1a-1） [ N（39.32–62.04 kg ha-1a-1） [ K（15.95–22.44 kg ha-1a-1） [ P（1.30–1.63 kg ha-1a-1）. C, N, K and P input to soil was significantly lower in the 10-year-old stand in comparison to the 22- and34-year-old stands（p ／ 0.05）. Litterfall production and nutrient return（C, N and K） followed similar patterns, and C and N input to soil was significantly related to litterfall production（needle, branch and total litterfall）. C, N, P and K input to soil and total litterfall production were mainly driven by needle litterfall.

Towards understanding the mechanism of n-hexane tolerance in Synechocystis sp.PCC 6803

Synthetic biology efforts have also led to the development of photosynthetic cyanobacteria as"autotrophic cell factories"for biosynthesis of various biofuels directly from CO_(2).However,the low tolerance to toxicity of biofuels has restricted the economic application of cyanobacterial hosts.In this study,RNAseq transcriptomics was employed to reveal stress responses to exogenous n-hexane in Synechocystis sp.PCC 6803.Functional enrichment analysis of the transcriptomic data showed that signal transduction systems were induced significantly.To further identify regulatory genes related to n-hexane tolerance,a library of transcriptional regulators(TRs)deletion mutants was then screened for their roles in nhexane tolerance.The results showed that a knockout mutant of slr0724 that encodes an Hta R suppressor protein was more tolerant to n-hexane than the wild type,indicating the involvement of slr0724 in nhexane tolerance.This study provides the foundation for better understanding the cellular responses to n-hexane in Synechocystis sp.PCC 6803,which could contribute to the further engineering of nhexane tolerance in cyanobacteria.

长链非编码RNA在非小细胞肺癌EGFR-TKIs耐药中的研究进展

携带表皮生长因子受体(epidermal growth factor receptor,EGFR)突变的非小细胞肺癌(non-small cell lung cancer,NSCLC)患者经EGFR酪氨酸激酶抑制剂(EGFR tyrosine kinase inhibitors,EGFR-TKIs),如吉非替尼长期治疗后,其中的绝大部分患者会最终发生获得性耐药,导致疾病进展。EGFR-TKIs耐药涉及多种机制。目前对长链非编码RNA(long non-coding RNA,lncRNA)在EGFR-TKIs耐药中的作用还知之甚少。本文旨在对lncRNAs在NSCLC EGFR-TKIs耐药中的研究进展进行综述。

Genome-wide identification and evolutionary analysis of MLO gene family in Rosaceae plants

Mutants lacking wild-type MLO(Mildew resistance Locus O)proteins show broad-spectrum resistance to the powdery mildew fungus,and dysregulated cell death control,with spontaneous cell death in response to developmental or abiotic stimuli.In order to understand the evolution and divergence patterns of the MLO gene family in Rosaceae plants,we analysed systematically genome-wide data from Fragaria vesca,Prunus persica,Prunus mume,Malus domestica,Pyrus bretschneideri and Rubus occidentalis based on bioinformatics methods.Using three phylogenetic methods(the neighbour-joining,maximum likelihood,and Bayesian methods),we identified 117 MLO genes from 6 Rosaceae species.The results of all three phylogenetic analysis methods supported that these genes were divided into six clades.Conserved motif analysis found that only motif 2 was present in all MLO proteins and had 3 nearly invariant amino acid residues.The findings indicated that motif 2 might be shared by the MLO gene family.The structural features of these genes showed large variations in sequence length among different species,although the lengths and the numbers of exons exhibited high degrees of similarity.Selective pressure analysis showed extremely significant differences in all 6 clades,with 2,1,and 1 site(s)under significant positive selection detected in clades III,IV,and VI,respectively.These positive selection sites were important driving forces for the promotion of the functional differentiation of the MLO genes.Functional divergence analysis showed that the significantly divergent sites were located within the domains of the MLO genes.Functional distance analysis showed that the clade V had more conservative functions and might have retained more original functions during the evolutionary process.However,clade I may have undergone extensive altered functional constraints as a specialised functional role.Moreover,the most original function of the MLO genes in Rosaceae could be related to the evolution of their resistance to powdery mildew,which then gradually evolved into functions such as the regulation of flower development,the control of root morphology,and seed evolution due to the different evolutionary rates after gene duplication.These results provide a theoretical basis for further studies of the molecular evolutionary patterns of the plant MLO gene family.

不同固结程度海洋软土动强度试验研究

为研究循环应力比和频率对不同超固结比的海洋软土动强度的影响,本文对珠江海洋软土进行室内动三轴试验,并对试验结果进行拟合分析。试验结果表明:总应变随着频率和超固结比的增大而减小,随着循环应力比的增大而增大;软化指数随着振次、循环荷载的增大而减小,随着频率的增大而增大;对软化曲线和动强度曲线进行回归分析,分别得到关于超固结比的软化系数和动强度经验公式。

Multi-energy Storage System Model Based on Electricity Heat and Hydrogen Coordinated Optimization for Power Grid Flexibility

Based on decreasing the flexibility of the power grid through the integration of large-scale renewable energy,a multi-energy storage system architectural model and its coor-dination operational strategy with the same flexibility as in the pumped storage power station and battery energy storage system(BESS)are studied.According to the new energy fluctuation characteristics and the different peak valley parameters in the power grid,this paper proposes a electricity heat hydrogen multi-energy storage system(EHH-MESS)and its coordination and optimization operational model to reduce the curtailment of wind power and photovoltaic(PV)to the power grid and improve the flexibility of the power grid.Finally,this paper studied the simulation model of an energy storage optimization control strategy after the multi-energy storage system is connected to the distribution networks,and analyzed three operational modes of the multi-energy storage system.The simulation results show that the EHH-MESS proposed in this paper has a better power grid regulation flexibility and economy,and can be used to replace the battery energy storage system based on MATLAB.

A green method to synthesize flowerlike Fe(OH)3 microspheres for enhanced adsorption performance toward organic and heavy metal pollutants

Dyestuffs and heavy metal ions in water are seriously harmful to the ecological environment and human health. Three-dimensional （3D） flowerlike Fe（OH）3 microspheres were synthesized through a green yet low-cost injection method, for the removal of organic dyes and heavy metal ions. The Fe（OH）3 microspheres were characterized by thermal gravimetric analysis （TGA）, Fourier transform infrared （FT-IR}, and transmission electron microscopy （TEM） techniques. The adsorption kinetics of Congo Red （CR） on Fe（OH）3 microspheres obeyed the pseudo-second-order model. Cr6＋ and Pb2＋ adsorption behaviors on Fe（OH）3 microspheres followed the Langmuir isotherm model. The maximum adsorption capacities of the synthesized Fe（OH）3 were 308, 52.94, and 75.64 mg/g for CR, Cr6＋, and Pb2＋ respectively. The enhanced adsorption performance originated from its surface properties and large specific surface area of 250 m2/g. The microspheres also have excellent adsorption stability and recyclability. Another merit of the Fe（OH）3 material is that it also acts as a Fenton-like catalyst. These twin functionalities （both as adsorbent and Fenton-like catalyst） give the synthesized Fe（OH）3 microspheres great potential in the field of water treatment.

聚球藻UTEX 2973中光碳驱动的高密度燃料合成

发展"液态阳光"被认为是解决化石燃料枯竭的关键技术之一。β-石竹烯是高性能的萜烯化合物,作为潜在的航空高密度燃料备受瞩目。新型光合蓝细菌底盘聚球藻UTEX 2973倍增时间短至1.5 h且耐受高温高光,利用光和CO_2合成β-石竹烯具有很大的发展前景。为此,文中在聚球藻UTEX2973中通过构建β-石竹烯合成途径、优化相关关键合酶、增强前体供应等一系列策略实现了在摇瓶中约121.22μg/Lβ-石竹烯的合成(96 h)。在此基础上,通过培养条件的优化实现在光生物反应器中进行高密度培养,最终β-石竹烯产量达到约212.37μg/L(96h)。这是目前报道的蓝细菌底盘中β-石竹烯的最高产量,为未来利用光和CO_2直接合成高密度燃料打下基础。