Essential (Mg,Fe, Zn and Cu) and Non-Essential (Cd and Pb) Elements in Predatory Insects (Vespa crabro and Vespa velutina): A Molecular Perspective

The recent introduction of the Asian yellow-legged hornet, Vespa velutina, into Europe has raised concern regarding the threat to honeybees and the competition with the European hornet, Vespa crabro. The aim of this study was to investigated essential (Mg, Fe, Zn, Cu) and non-essential (Cd and Pb) elements in these two species. Element concentrations were determined in the whole body and separately in the head, thorax and abdomen using atomic absorption spectrometry (AAS). The changes in essential element concentration and speciation during metamorphosis were also studied using size exclusion chromatography followed by AAS and proteomic analysis. In both species, the essential elements were more concentrated in the abdomen due to the presence of fat bodies. Magnesium, Fe and Zn concentrations were significantly higher in V. crabro than in V. velutina and could have been related to the higher aerobic energy demand of the former species required to sustain foraging flight. Low concentrations of Cd and Pb were indicative of low environmental exposure. The concentration and speciation of essential elements, particularly Fe, varied among the developmental stages, indicating a modification of ligand preferences during metamorphosis. Overall, the results in the present study provide a better understanding of the hornet metal metabolism and a foundation for additional studies.     

A Structure−Activity Relationship Study of Novel Hydroxamic Acid Inhibitors around the S1 Subsite of Human Aminopeptidase N

Aminopeptidase N (APN/CD13) is a zinc-dependent ubiquitous transmembrane ectoenzyme that is widely present in different types of cells. APN is one of the most extensively studied metalloaminopeptidases as an anti-cancer target due to its significant role in the regulation of metastasis and angiogenesis. Previously, we identified a potent and selective APN inhibitor, N-(2-(Hydroxyamino)-2-oxo-1-(3′,4′,5′-trifluoro-[1,1′-biphenyl]-4-yl)ethyl)-4-(methylsulfonamido)benzamide ( 3 ). Herein, we report the further modifications performed to explore SAR around the S1 subsite of APN and to improve the physicochemical properties. A series of hydroxamic acid analogues were synthesised, and the pharmacological activities were evaluated in vitro. N-(1-(3′-Fluoro-[1,1′-biphenyl]-4-yl)-2-(hydroxyamino)-2-oxoethyl)-4-(methylsulfonamido)benzamide ( 6 f ) was found to display an extremely potent inhibitory activity in the sub-nanomolar range.     

Evaluation of structural properties of AZO conductive films modification using low-temperature ultraviolet laser annealing

In this study, an ultraviolet (355 nm) laser processing system was developed to anneal aluminum-doped zinc oxide (AZO) thin films at room temperature in an air atmosphere; in this system, two key parameters, laser fluence and annealing speed, were varied. The structural properties of the films were thoroughly examined using field emission scanning electron microscopy, atomic force microscopy, and X-ray diffraction (XRD). The results showed that the laser fluence not only influenced the structural properties of the films, but also improved the crystallinity of the films after the laser annealing process, with minimal changes in the thickness of the films and the concentration of the elements in the films. The root mean square surface roughness (R_rms) of the films gradually increased as the laser fluence increased. Moreover, according to the XRD pattern of the films, the intensity of the main peak corresponding to the (002) direction increased as the laser fluence increased. The average crystallite size (20 nm) of the annealed films, determined using the Scherrer equation, was smaller than that of the as-deposited thin film (22 nm) due to the low temperature effect in the laser annealing process.     

不同消解方法对土壤中铜锌测定的影响

采用微波消解法和石墨消解法对土壤样品进行预处理,用火焰原子吸收分光光度法测定土壤中铜和锌的含量。对3个土壤标准物质(GSS-17、GSS-30、GSS-34)的精密度和准确度进行了分析,结果表明:微波消解法和石墨消解法的检出限、精密度和准确度均能满足土壤检测的要求,石墨消解法相对于微波消解法更加便捷,具有很好的精密度和准确度。     

Designing zinc oxide nanostructures (nanoworms,nanoflowers, nanowalls,and nanorods) by pulsed laser ablation technique for gas-sensing application

In this study, pulsed laser ablation technique, also known as pulsed laser deposition (PLD), is used to design and grow zinc oxide (ZnO) nanostructures (nanoworms, nanowalls, and nanorods) by template/seeding approach for gas-sensing applications. Conventionally, ZnO nanostructures used for gas-sensing have been usually prepared via chemical route, where the 3D/2D nanostructures are chemically synthesized and subsequently plated on an appropriate substrate. However, using pulsed laser ablation technique, the ZnO nanostructures are structurally designed and grown directly on a substrate using a two-step temperature-pressure seeding approach. This approach has been optimized to design various ZnO nanostructures by understanding the effect of substrate temperature in the 300-750°C range under O₂ gas pressure from 10-mTorr to 10 Torr. Using a thin ZnO seed layer as template that is deposited first at substrate temperature of ~300°C at background oxygen pressure of 10 mTorr on Si(100), ZnO nanostructures, such as nanoworms, nanowalls, and nanorods (with secondary flower-like growth) were grown at substrate temperatures and oxygen background pressures of (550°C and 2 Torr), (550°C and 0.5 Torr), and (650°C and 2 Torr), respectively. The morphology and the optical properties of ZnO nanostructures were examined by Scanning Electron Microscope (SEM-EDX), X-ray Diffraction (XRD), and photoluminescence (PL). The PLD-grown ZnO nanostructures are single-crystals and are highly oriented in the c-axis. The vapor-solid (VS) model is proposed to be responsible for the growth of ZnO nanostructures by PLD process. Furthermore, the ZnO nanowall structure is a very promising nanostructure due to its very high surface-to-volume ratio. Although ZnO nanowalls have been grown by other methods for sensor application, to this date, only a very few ZnO nanowalls have been grown by PLD for this purpose. In this regard, ZnO nanowall structures are deposited by PLD on an Al₂O₃ test sensor and assessed for their responses to CO and ethanol gases at 50 ppm, where good responses were observed at 350 and 400°C, respectively. The PLD-grown ZnO nanostructures are very excellent materials for potential applications such as in dye-sensitized solar cells, perovskite solar cells and biological and gas sensors.     

A Complexing Agent to Enable a Wide-Temperature Range Bromine-Based Flow Battery for Stationary Energy Storage

Bromine-based flow batteries (Br-FBs) are considered one of the most promising energy storage systems due to their features of high energy density and low cost. However, they generally suffer from uncontrolled diffusion of corrosive bromine particularly at high temperatures. That is because the interaction between polybromide anions and the commonly used complexing agent (N–methyl–N–ethyl–pyrrolidinium bromide [MEP]) decreases with increasing temperatures, which causes serious self-discharge and capacity fade. Herein, a novel bromine complexing agent, 1–ethyl–2–methyl–pyridinium bromide (BCA), is introduced in Br-FBs to solve the above problems. It is proven that BCA can combine with polybromide anions very well even at a high temperature of 60 °C. Moreover, the BCA contributes to decreasing the electrochemical polarization of Br⁻/Br₂ couple, which in turn improves their power density. As a result, a zinc–bromine flow battery with BCA as the complexing agent can achieve a high energy efficiency of 84% at 40 mA cm⁻², even at high temperature of 60 °C and it can stably run for more than 400 cycles without obvious performance decay. This paper provides an effective complexing agent to enable a wide temperature range Br-FB.     

ZnO Nanoplatelets with Controlled Thickness: Atomic Insight into Facet-Specific Bimodal Ligand Binding Using DNP NMR

Colloidal nanoplatelets (NPLs) and nanosheets with controlled thickness have recently emerged as an exciting new class of quantum-sized nanomaterials with substantially distinct optical properties compared to 0D quantum dots. Zn-based NPLs are an attractive heavy-metal-free alternative to the so far most widespread cadmium chalcogenide colloidal 2D semiconductor nanostructures, but their synthesis remains challenging to achieve. The authors describe herein, to the best of their knowledge, the first synthesis of highly stable ZnO NPLs with the atomically precise thickness, which for the smallest NPLs is 3.2 nm (corresponding to 12 ZnO layers). Furthermore, by means of dynamic nuclear polarization-enhanced solid-state ¹⁵N NMR, the original role of the benzamidine ligands in stabilizing the surface of these nanomaterials is revealed, which can bind to both the polar and non-polar ZnO facets, acting either as X- or L-type ligands, respectively. This bimodal stabilization allows obtaining hexagonal NPLs for which the surface energy of the facets is modulated by the presence of the ligands. Thus, in-depth study of the interactions at the organic–inorganic interfaces provides a deeper understanding of the ligand–surface interface and should facilitate the future chemistry of stable-by-design nano-objects.     

Comparative study of microwave absorption properties of Ni–Zn ferrites obtained from different synthesis technologies

Spinel ferrites are widely used for electromagnetic wave (EMW) absorption applications. In this study, spinel Ni–Zn ferrites with excellent microwave absorption properties were synthesized. Their EMW absorption characteristics and interaction mechanisms were studied to lay the foundation for the study of the role of Ni–Zn ferrite as a magnetic substrate for composites. Herein, Ni_0·5Zn_0·5Fe₂O₄ was prepared by the hydrothermal method (H-NZFO) and the sol–gel auto-combustion method (S-NZFO); both samples exhibited distinct microwave absorption properties. The S-NZFO absorber (thickness = 3.72 mm) demonstrated the best dual-zone microwave absorption with two strong reflection loss peaks at 5.1 and 10.5 GHz. The corresponding effective absorption bandwidth (EAB) reached 9.0 GHz, which covered part of the S-band and all of the C- and X-bands. These results were attributed to the high saturation magnetization, outstanding complex permeability, and multiple magnetic loss channels of S-NZFO. The H-NZFO sample exhibited excellent absorption capability and matching thickness. At a thickness as low as 1.71 mm, the minimum reflection loss (RL_min) of the H-NZFO absorber reached -60.2 dB at 13.1 GHz. The maximum bandwidth corresponding to RL below -10 dB was 4.6 GHz. These results can be attributed to small particle size, high complex permittivity, and multiple dielectric loss channels of H-NZFO. The observed wide effective absorption bandwidth of S-NZFO and strong microwave absorption capability of H-NZFO suggest the potential of both materials as substrates for efficient microwave absorbers in military as well as civilian absorption applications.     

含金高硫铜锌多金属硫化矿浮选分离试验研究

我国某难选铜锌多金属硫化矿,铜锌硫矿物共生关系密切,且次生硫化铜矿物的含量较高,致使铜锌硫矿物分离难度较大。依据矿石特性,试验研究采用一段细磨—铜锌硫等可浮—铜锌硫分离—锌浮选的工艺流程,使用石灰、TW、硫酸锌和亚硫酸钠组合药剂作锌矿物的抑制剂,使用选择性较好的Z-200作为铜矿物的捕收剂,实现了铜锌矿物的有效分离,试验室闭路试验获得的铜精矿品位23.23%、铜回收率91.45%,锌精矿品位49.53%、锌回收率85.36%,硫精矿品位44.25%、回收率59.16%,分离指标较为理想。