Use of back-scatter electron signals to visualise cell/nanowires interactions in vitro and in vivo; frustrated phagocytosis of long fibres in macrophages and compartmentalisation in mesothelial cells in vivo

ABSTRACT: BACKGROUND: Frustrated phagocytosis has been stated as an important factor in the initiation of an inflammatory response after fibre exposure. The length of fibrous structures has been linked to the potential of fibres to induce adverse health effects for at least 40 years. However, we only recently reported for the first time the threshold length for fibre-induced inflammation in the pleural space and we implicated frustrated phagocytosis in the pro-inflammatory effects of long fibres. This study extends the examination of the threshold value for frustrated phagocytosis using well-defined length classes of silver nanowires (AgNW) ranging from 3--28 mum and describes in detail the morphology of frustrated phagocytosis using a novel technique and also describes compartmentalisation of fibres in the pleural space. METHODS: A novel technique, backscatter scanning electron microscopy (BSE) was used to study frustrated phagocytosis since it provides high-contrast detection of nanowires, allowing clear discrimination between the nanofibres and other cellular features. A human monocyte-derived macrophage cell line THP-1 was used to investigate cell-nanowire interaction in vitro and the parietal pleura, the site of fibre retention after inhalation exposure was chosen to visualise the cell- fibre interaction in vivo after direct pleural installation of AgNWs. RESULTS: The length cut-off value for frustrated phagocytosis differs in vitro and in vivo. While in vitro frustrated phagocytosis could be observed with fibres [GREATER-THAN OR EQUAL TO]14 mum, in vivo studies showed incomplete uptake at a fibre length of [GREATER-THAN OR EQUAL TO]10 mum. Recently we showed that inflammation in the pleural space after intrapleural injection of the same nanofibre panel occurs at a length of [GREATER-THAN OR EQUAL TO]5 mum. This onset of inflammation does not correlate with the onset of frustrated phagocytosis as shown in this study, leading to the conclusion that intermediate length fibres fully enclosed within macrophages as well as frustrated phagocytosis are associated with a pro-inflammatory state in the pleural space. We further showed that fibres compartmentalise in the mesothelial cells at the parietal pleura as well as in inflammatory cells in the pleural space. CONCLUSION: BSE is a useful way to clearly distinguish between fibres that are, or are not, membrane-bounded. Using this method we were able to show differences in the threshold length at which frustrated phagocytosis occurred between in vitro and in vivo models. Visualising nanowires in the pleura demonstrated at least 2 compartments -- in leukocyte aggregations and in the mesothelium - which may have consequences for long term pathology in the pleural space including mesothelioma.     

Temperature programmed desorption study of adsorbed species formed by the decomposition of N2O on ion-exchanged copper zeolite catalysts

The nature of the adsorbed species on Cu-ZSM-5 (Cu-Z), Cu-Mordenite (Cu-M), and Cu-Y-zeolite (Cu-Y) was investigated by means of temperature programmed desorption (TPD). When dinitrogen monoxide (N₂O) came into contact with Cu-zeolites above 573 K, the decomposition of N₂O occurred accompanied by the formation of adsorbed oxygen species and adsorbed nitrogen oxide species. In the TPD runs, three O₂ desorption peaks appeared at temperatures of 623, 673, and 753 K and were named -, β-, and γ-peaks, respectively. The O₂ desorption at the - and γ-peaks became quickly saturated after contacting N₂O at 598 K, while the amount of O₂ desorbed at the β-peak increased with time, not reaching a constant level until 120 min of exposure. The activity for the decomposition of N₂O decreased with the accumulation of β-oxygen over the catalyst. The rate of N₂O decomposition depended upon the nature and amount of the copper zeolite catalysts available, as determined by the formation of - and/or β-oxygen.     

Recommended weightings for colorimetric calculations*

Several different sets of weighting functions are, or have been, in routine use in colour-measurement systems employed in industry to represent the same pairings of illuminant and observer. Exactly the same inputs to different weight-sets purporting to represent the same pairing give, often significantly, different outputs (e. g. colour-difference reports), leading to confusion, arguments between suppliers and their customers, and loss of faith in the capabilities of systems. The extent of variation between weight-sets is exemplified by those employed, at some time, by some of the major system suppliers to represent TL84. The practical effect of these variations is examined and a recommendation is made to use the weight-sets in ASTM E308-96. The relevant content of E308-96 is summarised and means of determining whether E308-96 weights are installed in a system are given. Tables of E308-96 weighting functions for CIE illuminants A, D₆₅ and F11 (TL84) are appended.     

Adsorption of sulfur on heated (10\overline 1 0) Re

High-resolution Auger electron spectroscopy is used to study the adsorption of sulfur on a Re surface and to determine the regions of thermal stability of the resulting adsorption states. The formation of surface sulfide is observed and its stoichiometry, Re₂S, and the absolute sulfur concentration on the rhenium surface N _S =(6.0±1)×10¹⁴ atom/cm² are determined. It is shown that the surface sulfide is destroyed by thermal desorption of sulfur from the rhenium surface and the desorption activation energy is estimated as E _d =(3.3±0.2) eV for a coverage close to the surface sulfide and E _d =(4.9±0.2) eV in the limit θ→0. Pis’ma Zh. Tekh. Fiz. 25, 57–64 (July 26, 1999)     

Microstructure and Mechanical Properties of ZrO2(2Y)-Toughened Al2O3 Ceramics Fabricated by Spark Plasma Sintering

Spark plasma sintering (SPS) has been performed for 5 min at 1500°C and 30 MPa using submicrometer-sized Al₂O₃/ZrO₂(2Y) composite powders in the Al₂O₃-rich region. Dense ZrO₂-toughened Al₂O₃ (ZTA) ceramics show excellent mechanical strength; the strength of 1620 MPa is achieved in the ZTA with 50 mol% ZrO₂. The grain size of Al₂O₃ in ZTA decreases from 1.5 to 0.6 m with increased ZrO₂ content. Almost all the ZrO₂ grains (0.3 m) are located in the boundaries of the Al₂O₃ grains. Mechanical properties are discussed, with an emphasis on the relation between t-/m-ZrO₂ ratios and microstructures of ZTA.     

Morphology and Performance Enhancement through the Strong Passivation Effect of Amphoteric Ions in Tin-based Perovskite Solar Cells

Despite the optoelectronic similarities between tin and lead halide perovskites, the performance of tin-based perovskite solar cells remains far behind, with the highest reported efficiency to date being ≈14%. This is highly correlated to the instability of tin halide perovskite, as well as the rapid crystallization behavior in perovskite film formation. In this work, l -Asparagine as a zwitterion plays a dual role in controlling the nucleation/crystallization process and improving the morphology of perovskite film. Furthermore, tin perovskites with l -Asparagine show more favorable energy-level matching, enhancing the charge extraction and minimizing the charge recombination, leading to an enhanced power conversion efficiency of 13.31% (from 10.54% without l -Asparagine) with remarkable stability. These results are also in good agreement with the density functional theory calculations. This work not only provides a facile and efficient approach to controlling the crystallization and morphology of perovskite film but also offers guidelines for further improved performance of tin-based perovskite electronic devices.     

Revealing the Cooperative Relationship between Spin,Energy, and Polarization Parameters toward Developing High‐Efficiency Exciplex Light‐Emitting Diodes

Experimental studies to reveal the cooperative relationship between spin, energy, and polarization through intermolecular charge‐transfer dipoles to harvest nonradiative triplets into radiative singlets in exciplex light‐emitting diodes are reported. Magneto‐photoluminescence studies reveal that the triplet‐to‐singlet conversion in exciplexes involves an artificially generated spin‐orbital coupling (SOC). The photoinduced electron parametric resonance measurements indicate that the intermolecular charge‐transfer occurs with forming electric dipoles (D^+?→A^??), providing the ionic polarization to generate SOC in exciplexes. By having different singlet‐triplet energy differences (ΔE_ST) in 9,9′‐diphenyl‐9H,9′H‐3,3′‐bicarbazole (BCzPh):3′,3′″,3′″″‐(1,3,5‐triazine‐2,4,6‐triyl)tris(([1,1′‐biphenyl]‐3‐carbonitrile)) (CN‐T2T) (ΔE_ST = 30 meV) and BCzPh:bis‐4,6‐(3,5‐di‐3‐pyridylphenyl)‐2‐methyl‐pyrimidine (B3PYMPM) (ΔE_ST = 130 meV) exciplexes, the SOC generated by the intermolecular charge‐transfer states shows large and small values (reflected by different internal magnetic parameters: 274 vs 17 mT) with high and low external quantum efficiency maximum, EQE_max (21.05% vs 4.89%), respectively. To further explore the cooperative relationship of spin, energy, and polarization parameters, different photoluminescence wavelengths are selected to concurrently change SOC, ΔE_ST, and polarization while monitoring delayed fluorescence. When the electron clouds become more deformed at a longer emitting wavelength due to reduced dipole (D^+?→A^??) size, enhanced SOC, increased orbital polarization, and decreased ΔE_ST can simultaneously occur to cooperatively operate the triplet‐to‐singlet conversion.     

LabVIEW与PSpice相结合用于分析和设计电子电路

阐述了将LabVIEW与PSpice相结合用于分析和设计电子电路的方法,并通过一个高通滤波器的设计作为实例,着重说明了如何用Labview语言读取PSpice仿真所得数据。这样就可将PSpice的仿真结果和设计原型通过LabVIEW获得的真实测量值相结合,设计工程师们可以更快速见到仿真结果与实际测量值的差异,从而在产品研发过程中快速诊断误差所在,并进行相应性能调整。     

基于新的优化修正函数的模糊控制器设计

本文提出了一种基于新的优化修正函数的模糊控制方法,该方法根据误差E和误差变化EC修改规则调整因子α,不仅体现了按误差大小自动调节误差E对控制作用的权重,而且也考虑到误差变化EC在系统的各个运行阶段时控制性能有不同的影响,从而使该模糊控制器具有更好的适应非线性、时变、不确定性等复杂难控对象的能力。最后利用MATLAB的SIMULINK进行仿真研究,结果表明,该控制器具有较强的抗干扰能力和鲁棒性,有较好的动、静态控制精度。     

基于新的优化修正函数的模糊控制器设计

本文提出了一种基于新的优化修正函数的模糊控制方法,该方法根据误差E和误差变化EC修改规则调整因子α,不仅体现了按误差大小自动调节误差E对控制作用的权重,而且也考虑到误差变化EC在系统的各个运行阶段对控制性能有不同的影响,从而使该模糊控制器具有更好的适应非线性、时变、不确定性等复杂难控对象的能力.最后利用MATLAB的SIMULINK进行仿真研究,结果表明,该控制器具有较强的抗干扰能力和鲁棒性,有较好的动、静态控制精度.