Charge transport in a mixed ionically/electronically conducting, cationic, polyacetylene ionomer between ion-blocking electrodes

The electrical behavior of the cationic, polyacetylene-based, conjugated ionomer, poly[(2-cyclooctatetraenylethyl)trimethylammonium trifluoromethanesulfonate], sandwiched between gold electrodes is reported. The steady-state current of this mixed ionically/electronically conducting system is assigned to be unipolar diffusive hole transport for voltages below approximately 1.4 V, giving way to bipolar migratory transport above approximately 1.4 V. In the low-voltage regime, a non-Faradaically controlled doping model is proposed where p-doping at the anode is balanced by the charging of an ionic double layer at the cathode. In the high-voltage regime, n- and p-type regions extend from the electrodes as the voltage becomes sufficient to drive disproportionation and the electric field required by the redistribution of ions begins to substantially influence carrier transport. The assignment of a transport mechanism is primarily based on analyzing the decay of the steady-state system under short-circuit and open-circuit conditions. First, it is shown that the power describing the power-law decay of the short-circuit current is characteristic of the steady-state carrier profile. Second, it is argued that a component of the time-dependent, open-circuit voltage decaying more rapidly than the time scale for ion motion is indicative of a substantial migratory component to steady-state transport, as observed in the high-voltage regime. The hole and electron mobilities are estimated to be on the order of 10(-7)-10(-6) cm(2) V(-1) s(-1).     

A direct hydrogen-1 and phosphorus-31 nuclear magnetic resonance cation solvation study of Al(ClO4)3, Ga(ClO4)3, In(ClO4)3, UO2(ClO4)2, and UO2(NO3)2 in water-acetone-dimethylsulfoxide and water-acetone-hexamethylphosphoramide mixtures

A competitive solvation study of Al(ClO₄)₃, Ga(ClO₄)₃, In(ClO₄)₃, UO₂(ClO₄)₂, and UO₂(NO₃)₂ in water-acetone-dimethylsulfoxide (DMSO) and water-acetone-hexamethylphosphoramide (HMPT) mixtures has been carried out by direct H¹ and P³¹ nuclear magnetic resonance (NMR) techniques. At low temperature, proton and ligand exchange are slow enough in these systems to permit the observation of signals for bulk and coordinated molecules of water and the organic bases (DMSO and HMPT). Both DMSO and HMPT compete effectively with water for coordination sites in the Al³⁺, Ga³⁺, and In³⁺ systems, with steric effects dominating the HMPT results. Both Al³⁺ and In³⁺ are able to bind a maximum of two to three HMPT molecules, for example. In contrast, UO²⁺ is solvated selectively by the organic molecules to the allowed maximum of 4 molecules per cation. H¹ and P³¹ NMR spectral results support the formation of only the mono-, tri-, and tetra-HMPT solvation complexes.     

Polymerization of w/o microemulsions for the preparation of transparent SiO2/PMMA nanocomposites

Reverse w/o microemulsions composed of methyl methacrylate (MMA) forming the oil phase, nonionic surfactants, and water are used for the synthesis of transparent SiO2/PMMA nanocomposites. An inorganic precursor, tetraethoxysilane (Si(OEt)(4), TEOS), is hydrolyzed in the reverse micelles containing aqueous ammonia. During the hydrolysis of TEOS, polymerization of the continuous MMA phase is initiated using AIBN (azobisisobutyronitrile), and after thermal polymerization at 333 K for 12 h, solid blocks of PMMA are obtained in which nanometer-sized silica particles are trapped in the solid polymer matrix. According to small-angle X-ray and dynamic light scattering experiments, the water droplets in MMA microemulsions are 12 nm (R(W) = 13) in diameter, whereas after polymerization of the microemulsion, the SiO2 particles in the transparent SiO2/PMMA composites are 26 nm in diameter. Transmission electron micrographs demonstrate a low degree of agglomeration in the composites. In comparison with materials generated from micelle-free solutions, the particle size distribution is narrow. The reverse micelle-mediated approach produces composites of high transparency comparable with that of pure PMMA.     

A near-infrared Fourier transform Raman spectroscopy of epidermal keratinocytes: changes in the protein-DNA structure following malignant transformation

We report here the use of near-infrared (NIR) Fourier transform (FT) Raman spectroscopy to analyze normal human epidermal keratinocytes prior to and following malignant transformation. Our analysis indicates specific Raman spectral differences between immortalized (HPK1A) and malignant ras transformed (HPK1A-ras) cells. In addition, striking spectral differences are seen in the DNA isolated from these cells and particularly in the 843/810 cm(-1) ratio with values of 1.6 +/- 0.13 in HPK1A cells and 0.68 +/- 0.09 in HPK1A-ras cells (mean +/- S.D., n = 12, P < 0.001) indicating specific alterations in the backbone conformation markers following malignant transformation. Subsequently, we analysed the effect of a strong inhibitor of keratinocyte growth, the Vitamin D analog EB1089, on the Raman spectra of intact cells and on the 843/810 cm(-1) ratio in the DNA isolated from both cell lines. Specific changes were observed in intact cells in the 1300-750 cm(-1) region. Furthermore, the 843/810 cm(-1) ratio of isolated DNA from HPK1A cells was not affected by EB1089 but significantly increased in DNA isolated from HPK1A-ras cells so much that it became closer to the value observed for HPK1A cells (1.07 +/- 0.10). Our data suggest that Raman analysis of DNA and in particular the 843/810 cm(-1) ratio can provide useful indices of malignant transformation and efficacy of anticancer agents.     

Visible Light-Driven Alkyne-Grafted Ethylene-Bridged Azobenzene Chromophores for Photothermal Utilization

Molecular photoswitches are considered to be important candidates in the field of solar energy storage due to their sensitive and reversible bidirectional optical response. Nevertheless, it is still a daunting challenge to design a molecular photoswitch to improve the low solar spectrum utilization and quantum yields while achieving charging and discharging of heat without solvent assistance. Herein, a series of visible-light-driven ethylene-bridged azobenzene (b-Azo) chromophores with different alkyne substituents which can undergo isomerization reactions promoted in both directions by visible light are reported. Their visible light responsiveness improves their solar spectrum utilization while also having high quantum yields. In addition, as the compounds are liquids, there is no need to dissolve the compounds in order to exploit this switching. The photoisomerization of b-Azo can be adjusted by alkyne-related substituents, and hexyne-substituted b-Azo is able to store and release photothermal energy with a high density of 106.1 J·g⁻¹, and can achieve a temperature increase of 1.8 °C at a low temperature of −1 °C.     

Surface Functionalized Magnetic Nanoparticles as a Selective Sorbent for Affinity Fishing of PPAR-γ Ligands from Choerospondias axillaris

Coronary heart disease (CHD), which has developed into one of the major diseases, was reported to be treated by the target of peroxisome proliferators-activate receptor γ (PPAR-γ). As a natural medicine long used in the treatment of CHD, there are few studies on how to screen the target active compounds with high specific activity from Choerospondias axillaris. To advance the pace of research on target-specific active compounds in natural medicines, we have combined magnetic ligand fishing and functionalized nano-microspheres to investigate the active ingredients of PPAR-γ targets in Choerospondias axillaris. The PPAR-γ functionalized magnetic nano-microspheres have been successfully synthesized and characterized by vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The specificity, reusability, and reproducibility of the nano-microspheres were investigated with the help of the specific binding of rosiglitazone to PPAR-γ. In addition, the incubation temperature and the pH of the buffer solution in the magnetic ligand fishing were optimized to improve the specific adsorption efficiency of the analytes. Finally, with the aid of ultraperformance liquid chromatography plus Q-Exactive Orbitrap tandem mass spectrometry (UHPLC-Q-Exactive Orbitrap-MS/MS), the 16 active ligands including 9 organic acids, 5 flavonoids, and 2 phenols were found in the ethanolic extracts of Choerospondias axillaris. Therefore, the study can provide a successful precedent for realizing the designated extraction and rapid isolation of target-specific active ingredient groups in the complex mixtures.     

振动噪声等高图的电驱动桥噪声预测及优化*

在项目开发前期通过优化电驱动桥扭矩特性的设计,可以规避噪声大问题。根据电驱动桥台架在对应扭矩下的振动噪声特性,提出了一套稳定高效的测试流程和分析方法。首先设计了一套完整的试验流程,制定了精准的数据分析方法。然后绘制出能够全面反映电驱动桥振动噪声特性的等高图。最后利用电驱动桥台架的振动噪声等高图,准确评估电驱动桥加速工况下振动噪声风险,为主机厂和电驱动桥零部件企业提供电驱动桥扭矩特性设计前期指导。利用该方法成功识别到某电驱动桥匀速及加速工况下电机及齿轮的啸叫问题。通过优化电驱动桥扭矩特性设计,电机48阶噪声峰值降低了8.5dB(A),确认该方法准确可靠,具备推广应用价值。     

声波团聚净化尿素造粒塔尾气实验研究*

尿素造粒塔大多采用水洗工艺处理尾气粉尘,存在较为严重的细颗粒粉尘溢出和水汽拖尾问题,因此深入探究声波团聚技术在造粒塔尾气处理方面的应用。通过实验研究了声波与喷雾对除尘效率的影响,发现声波单独作用时在3500 Hz达到最佳除尘效率,为74.49%,协同喷雾时2600 Hz即可实现相近的除尘效率,为73.83%。进一步探究其中机理,采用以粒径测试为依据的团聚效率作为评价指标,结果显示,2600 Hz声波与喷雾单独作用时团聚效率分别为30.37%和28.82%,协同作用时团聚效率大幅提升至57.95%。该研究可为后续造粒塔工程改造提供理论与数据支持。     

Synthesis of PNIPAAm-g-P4VP Microgel as Draw Agent in Forward Osmosis by RAFT Polymerization and Reverse Suspension Polymerization to Improve Water Flux

Microgels have unique and versatile properties allowing their use in forward osmosis areas as a draw agent. In this contribution, poly(4-vinylpyridine) (P4VP) was synthesized via RAFT polymerization and then grafted to a poly(N-Isopropylacrylamide) (PNIPAAm) crosslinking network by reverse suspension polymerization. P4VP was successfully obtained by the quasiliving polymerization with the result of nuclear magnetic resonance and gel permeation chromatography characterization. The particle size and particle size distribution of the PNIPAAm-g-P4VP microgels containing 0, 5, 10, 15 and 20 wt% P4VP were measured by means of a laser particle size analyzer. It was found that all the microgels were of micrometer scale and the particle size was increased with the P4VP load. Inter/intra-molecular-specific interactions, i.e., hydrogen bond interactions were then investigated by Fourier infrared spectroscopy. In addition, the water flux measurements showed that all the PNIPAAm-g-P4VP microgels can draw water more effectively than a blank PNIPAAm microgel. For the copolymer microgel incorporating 20 wt% P4VP, the water flux was measured to be 7.48 L∙m⁻²∙h⁻¹.     

N-Butyrylated Hyaluronic Acid Achieves Anti-Inflammatory Effects In Vitro and in Adjuvant-Induced Immune Activation in Rats

Previously synthesized N-butyrylated hyaluronic acid (BHA) provides anti-inflammatory effects in rat models of acute gouty arthritis and hyperuricemia. However, the mechanism of action remains to be elucidated. Herein, the anti-inflammatory and antioxidative activities of BHA and the targeted signaling pathways were explored with LPS-induced RAW264.7 and an adjuvant-induced inflammation in a rat model. Results indicated that BHA inhibited the generation of pro-inflammatory cytokines TNFα, IL-1β and IL-6, reduced ROS production and down-regulated JAK1-STAT1/3 signaling pathways in LPS-induced RAW264.7. In vivo, BHA alleviated paw and joint swelling, decreased inflammatory cell infiltration in paw tissues, suppressed gene expressions of p38 and p65, down-regulated the NF-κB and MAPK signaling pathways and reduced protein levels of TNFα, IL-1β and IL-6 in joint tissues of arthritis rats. This study demonstrated the pivotal role of BHA in anti-inflammation and anti-oxidation, suggesting the potential clinical value of BHA in the prevention of inflammatory arthritis and is worthy for development as a new pharmacological treatment.