Enhanced Rate Capability of Ion‐Accessible Ti3C2Tx‐NbN Hybrid Electrodes

Although 2D Ti₃C₂T_x is a good candidate for supercapacitors, the restacking of nanosheets hinders the ion transport significantly at high scan rates, especially under practical mass loading (>10 mg cm^?2) and thickness (tens of microns). Here, Ti₃C₂T_x‐NbN hybrid film is designed by self‐assembling Ti₃C₂T_x with 2D arrays of NbN nanocrystals. Working as an interlayer spacer of Ti₃C₂T_x, NbN facilitates the ion penetration through its 2D porous structure; even at extremely high scan rates. The hybrid film shows a thickness‐independent rate performance (almost the same rate capabilities from 2 to 20 000 mV s^?1) for 3 and 50 µm thick electrodes. Even a 109 µm thick Ti₃C₂T_x‐NbN electrode shows a better rate performance than 25 µm thick pure Ti₃C₂T_x electrodes. This method may pave a way to controlling ion transport in electrodes composed of 2D conductive materials, which have potential applications in high‐rate energy storage and beyond.     

Tetraenol, a novel sesquiterpenoid from the relict plant Tetraena mongolica in China

A novel furansesquiterpenoid, tetraenol, was isolated from a relict shrub plant, Tetraena mongolica, collected from the northern desert of the Ningxia Hui Autonomous Region. The structure of the new compound was elucidated on the basis of spectroscopic analysis.     

Heat shock responsiveness analysis of <Emphasis Type="Italic">Athsp70b</Emphasis> upstream region

A 1431-bp upstream fragment of Athsp70b was cloned via PCR amplification and expressed in onion epidermis by particle bombardment. Furthermore, the progressive deletions of the Athsp70b upstream fragment linked to the β-glucuronidase (GUS) coding region were performed. Then, a stable GUS expression was analyzed in tobacco BY2 cells and Arabidopsis. Our present results showed that about a 500-bp region upstream ATG of Athsp70b is suitable to confer heat inducibility to the GUS reporter gene in plants and around 116 bp contain nonperfect heat-sensitive element. This promoter responds to heat, salicylic acid, and benzyladenine. GUS staining was mainly observed in the vascular tissues and root tips, implying that Athsp70b is related to water transportation.     

抑制AtCLH1表达降低叶片衰老进程中叶绿素a与b的比值但不影响叶绿素降解速率

为了分析叶绿素酶在叶绿素降解过程中的作用,构建了抑制AfCLH1和／或AtCLH2的拟南芥RNM株系。在RNAi株系中,叶绿素酶的表达和活性都被显著抑制。然而,无论是在正常生长情况下还是在黑暗诱导的衰老进程中,RN加株系中的叶绿素降解速率与野生型中的相比均无显著差异。进一步的分析结果表明,AtCLH1 RNAi株系中的叶绿素a/b比值在叶片衰老进程中逐渐降低,而野生型中的却逐渐升高。另外,还观察到所有株系中叶绿素酶的活性在黑暗诱导的衰老过程的初期均呈现出上升的趋势。与这一变化趋势正好相反,在所有株系中,叶绿素酶基因的表达在黑暗诱导衰老后就开始大幅下降。有趣的是,与野生型相比,RNAi株系中的目标叶绿素酶基因仍然维持在一个较低的表达水平。这说明拟南芥中可能存在一个反馈补偿机制。基于这些结果,并结合相关的研究报道,认为叶绿素酶很可能参与了衰老进程早期的叶绿素b向a的转换过程。     

Ammonium Removal by the Oxygen-Limited Autotrophic Nitrification-Denitrification System

The present lab-scale research reveals the potential of implementation of an oxygen-limited autotrophic nitrification-denitrification (OLAND) system with normal nitrifying sludge as the biocatalyst for the removal of nitrogen from nitrogen-rich wastewater in one step. In a sequential batch reactor, synthetic wastewater containing 1 g of NH₄⁺-N liter⁻¹ and minerals was treated. Oxygen supply to the reactor was double-controlled with a pH controller and a timer. At a volumetric loading rate (B_v) of 0.13 g of NH₄⁺-N liter⁻¹ day⁻¹, about 22% of the fed NH₄⁺-N was converted to NO₂⁻-N or NO₃⁻-N, 38% remained as NH₄⁺-N, and the other 40% was removed mainly as N₂. The specific removal rate of nitrogen was on the order of 50 mg of N liter⁻¹ day⁻¹, corresponding to 16 mg of N g of volatile suspended solids⁻¹ day⁻¹. The microorganisms which catalyzed the OLAND process are assumed to be normal nitrifiers dominated by ammonium oxidizers. The loss of nitrogen in the OLAND system is presumed to occur via the oxidation of NH₄⁺ to N₂ with NO₂⁻ as the electron acceptor. Hydroxylamine stimulated the removal of NH₄⁺ and NO₂⁻. Hydroxylamine oxidoreductase (HAO) or an HAO-related enzyme might be responsible for the loss of nitrogen.