Application of enzyme-linked immunosorbent assay for quantification of the insecticides imidacloprid and thiamethoxam in honey samples

An enzyme-linked immunosorbent assay (ELISA) was used for the determination of residues of imidacloprid and thiamethoxam insecticides in honey after simple dilution of the samples without either extraction or cleanup. The ELISA enabled accurate determination of imidacloprid and thiamethoxam down to limits of 20 and 5 ng g^?1 in honey, respectively. Average recoveries of imidacloprid and thiamethoxam from the fortified honey samples were 90–120 and 96–122%, and coefficients of variation ranged 5–12 and 3–15%, respectively. The results from the ELISA agreed well with those by liquid chromatography–mass spectrometry (LC–MS) for the insecticide-spiked samples, with a correlation coefficient (r ²) of 0.96 and a regression coefficient (slope) of 1.03. The results indicate that ELISA is a suitable tool for the quantification of imidacloprid and thiamethoxam in honey.     

Absorption-enhanced steam gasification of biomass for hydrogen production: Effect of calcium oxide addition on steam gasification of pyrolytic volatiles

The effect mechanism of calcium oxide (CaO) addition on gasification of pyrolytic volatiles as a key sub-process in the absorption-enhanced steam gasification of biomass (AESGB) for H₂ production at different conditions was investigated using a two-stage fixed-bed pyrolysis–gasification system. The results indicate that CaO functions as a CO₂ absorbent and a catalyst in the volatiles gasification process. CaO triggers the chemical equilibrium shift to produce more H₂ and accelerates volatile cracking and gasification reactions to obtain high volatile conversion rates. Increasing the gasification temperature could improve the reaction rate of cracking and gasification of volatiles as well as the catalytic effect of CaO, which continuously increase H₂ yield. When the gasification temperature exceeds 700 °C, the sharp decrease in CO₂ absorption capability of CaO drastically increases the CO₂ concentration and yield, which significantly decrease H₂ concentration. The appropriate temperature for the absorption-enhanced gasification process should be selected between 600 °C and 700 °C in atmospheric pressure. Increasing the water injection rate (represented as the mass ratio of steam to biomass) could also improve H₂ yield. The type of biomasses is closely associated with H₂ yield, which is closely related to the volatile content of biomass materials.     

Root-Zone CO2 Concentration Affects Partitioning and Assimilation of Carbon in Oriental Melon Seedlings

Root-zone CO₂ is essential for plant growth and metabolism. However, the partitioning and assimilation processes of CO₂ absorbed by roots remain unclear in various parts of the oriental melon. We investigated the time at which root-zone CO₂ enters the oriental melon root system, and its distribution in different parts of the plant, using ¹³C stable isotopic tracer experiments, as well as the effects of high root-zone CO₂ on leaf carbon assimilation-related enzyme activities and gene expressions under 0.2%, 0.5% and 1% root-zone CO₂ concentrations. The results showed that oriental melon roots could absorb CO₂ and transport it quickly to the stems and leaves. The distribution of ¹³C in roots, stems and leaves increased with an increase in the labeled root-zone CO₂ concentration, and the δ¹³C values in roots, stems and leaves increased initially, and then decreased with an increase in feeding time, reaching a peak at 24 h after ¹³C isotope labeling. The total accumulation of ¹³C in plants under the 0.5% and 1% ¹³CO₂ concentrations was lower than that in the 0.2% ¹³CO₂ treatment. However, the distributional proportion of ¹³C in leaves under 0.5% and 1% ¹³CO₂ was significantly higher than that under the 0.2% CO₂ concentration. Photosynthetic carbon assimilation-related enzyme activities and gene expressions in the leaves of oriental melon seedlings were inhibited after 9 days of high root-zone CO₂ treatment. According to these results, oriental melon plants’ carbon distribution was affected by long-term high root-zone CO₂, and reduced the carbon assimilation ability of the leaves. These findings provide a basis for the further quantification of the contribution of root-zone CO₂ to plant communities in natural field conditions.     

Hormone Regulation of CCCH Zinc Finger Proteins in Plants

CCCH zinc finger proteins contain one to six tandem CCCH motifs composed of three cysteine and one histidine residues and have been widely found in eukaryotes. Plant CCCH proteins control a wide range of developmental and adaptive processes through DNA–protein, RNA–protein and/or protein–protein interactions. The complex networks underlying these processes regulated by plant CCCH proteins are often involved in phytohormones as signal molecules. In this review, we described the evolution of CCCH proteins from green algae to vascular plants and summarized the functions of plant CCCH proteins that are influenced by six major hormones, including abscisic acid, gibberellic acid, brassinosteroid, jasmonate, ethylene and auxin. We further compared the regulatory mechanisms of plant and animal CCCH proteins via hormone signaling. Among them, Arabidopsis AtC3H14, 15 and human hTTP, three typical CCCH proteins, are able to integrate multiple hormones to participate in various biological processes.     

基于浙江省地标杭州某污水处理厂提标改造设计案例

杭州某污水处理厂原设计出水执行一级A标准,处理规模为14万m3/d.为满足更加严格的浙江省地标要求,该污水处理厂充分利用原有处理设施的基础上,对原有设施实施提标改造.对于污水处理厂接收的工业废水,TN、COD是提标改造的重点.工程调整回流比,确保足够的回流时间,新增臭氧氧化工艺,为相类似污水处理厂的提标改造提供参考.     

波纹丝网型太阳能空气集热器热性能特性研究

提出一种新型波纹丝网型太阳能空气集热器,根据集热器的传热关系,用Matlab建立数学模型,并搭建实验系统进行测试,验证模型的准确性.利用模型研究关键结构参数和运行参数对集热器热性能的影响规律.结果表明:出口温度和集热量的模拟值与实验值最大偏差分别为2.3 K和443％,当温度系数介于0.01～0.05时,波纹丝网型太阳...     

基于蒙特卡罗方法的矩形布局问题研究

根据蒙特卡罗方法产生的随机步长,控制矩形在布局空间中移动。矩形移动时,自动满足边界约束条件,简化了矩形可行域边界的计算过程。结合定位函数,得到的可行域可用于完成矩形的布局。测试结果表明,使用该方法求解矩形布局问题,布局空间90%以上被矩形占据。     

苏丹Azraq地区提高机械钻速的钻井液技术

针对苏丹Azraq地区地层特点,对提高机械钻速的钻井液性能参数进行研究,根据理论和实验优化钻井液性能参数。调整钻井液滤失量为6~8 m L,塑性黏度为15~20 m Pa s,动切力为10~15 Pa,动塑比为0.75 Pa/m Pa s。根据优化的钻井液性能参数,采用无土相的硅酸盐钻井液体系,并通过实验确定钻井液配方。现场应用证明,新的钻井液工艺能显著提高Abu Gbura地层的机械钻速,机械钻速由6~8 m/h提高到12~18 m/h,缩短了完井周期。Azraq K-9井创造了该地区完井时间的最短记录。     

Directed Urea-to-Nitrite Electrooxidation via Tuning Intermediate Adsorption on Co,Ge Co-Doped Ni Sites

The electrochemical urea oxidation reaction (UOR) is an alternative to electrooxidation of water for energy–saving hydrogen (H₂) production. To maximize this purpose, design of catalysts for selective urea-to-nitrite (NO₂^–) electrooxidation with increased electron transfer and high current is practically important. Herein, a cobalt, germanium (Co, Ge) co-doped nickel (Ni) oxyhydroxide catalyst is reported first time that directs urea-to-NO₂^– conversion with a significant Faradaic efficiency of 84.9% at 1.4 V versus reversible hydrogen electrode and significantly boosts UOR activity to 448.0 mA cm⁻². Importantly, this performance is greater than for most reported Ni-based catalysts. Based on judiciously combined synchrotron-based measurement, in situ spectroscopy and density functional theoretical computation, significantly boosted urea-to-NO₂^– production results from Co, Ge co-doping is demonstrated that optimizes electronic structure of Ni sites in which urea adsorption is altered as NO-terminal configuration to facilitate C N cleavage for *NH formation, and thereby expedites pathway for urea to NO₂^– conversion. Findings highlight the importance of tuning intermediate adsorption behavior for design of high-performance UOR electrocatalysts, and will be of practical benefit to a range of researchers and manufacturers in replacing conventional water electrooxidation with UOR for energy-saving H₂ production.     

A five-component entropy-stabilized fluorite oxide

In this paper, we report a new entropy-stabilized fluorite oxide, formed by solid-state reacting the equimolar mixture of CeO₂, ZrO₂, HfO₂, TiO₂ and SnO₂ at 1500?°C. We demonstrated that the oxide is truly entropy-stabilized by showing that the oxide was transferred to a multiphase state when annealed at lower temperatures, and the transition between the low-temperature multiphase and high-temperature single-phase states is reversible. Room-temperature thermal conductivity of the fluorite oxide was measured to be 1.28?Wm^?1?K^?1. The value is only half of that for 7?wt% yttria-stabilized zirconia, suggesting the material could be useful for thermal-insulation applications.