The activation of furfuryl alcohol polymerization by oxygen and its enhanced mechanical properties

The effect of oxygen and additional oxygen providers on furfuryl alcohol polymerization was investigated through chemical analyses and mechanical evaluation. NMR, UV–vis, Fourier transform infrared, and gas chromatography–mass spectrometry (GC–MS) results suggested that atmospheric oxygen and the further addition of an oxygen source functioned as an activator for the entire network polymerization. Interestingly, the construction of a conjugated structure on the furan linear chain, which is key to three-dimensional cross-linking, also appears to be accelerated in the presence of oxygen. Furthermore, the introduction of oxygen providers into the curing system successfully enhanced the mechanical properties of the cured furan resin.     

Effects of Winding Attachment Positions on Output Characteristics of Flux‐Modulating Synchronous Machines

The flux‐modulating synchronous machine (FMSM) is a new type of multipole SM with nonoverlapping concentrated armature and field windings on the stator. This paper compares the output characteristics of two FMSMs through finite element analysis (FEA) and experiments. In both of the FMSMs, the attachment positions of the armature and field windings are swapped. To determine the reason for the discrepancies in their output characteristics, unsaturated inductances were calculated using a d‐‐q equivalent circuit. In addition, the calculated results of the inductances were confirmed through a visualization of the leakage fluxes using FEA. The results of the study show that the synchronous inductance can be reduced by attaching the armature winding to the air‐gap side of the stator teeth and that the reduction leads to an increase in output power.     

Supramolecular Assembly of Aminoethylene‐Lipopeptide PMO Conjugates into RNA Splice‐Switching Nanomicelles

Phosphorodiamidate morpholino oligomers (PMOs) are oligonucleotide analogs that can be used for therapeutic modulation of pre‐mRNA splicing. Similar to other classes of nucleic acid‐based therapeutics, PMOs require delivery systems for efficient transport to the intracellular target sites. Here, artificial peptides based on the oligo(ethylenamino) acid succinyl‐tetraethylenpentamine (Stp), hydrophobic modifications, and an azide group are presented, which are used for strain‐promoted azide‐alkyne cycloaddition conjugation with splice‐switching PMOs. By systematically varying the lead structure and formulation, it is determined that the type of contained fatty acid and supramolecular assembly have a critical impact on the delivery efficacy. A compound containing linolenic acid with three cis double bonds exhibits the highest splice‐switching activity and significantly increases functional protein expression in pLuc/705 reporter cells in vitro and after local administration in vivo. Structural and mechanistic studies reveal that the lipopeptide PMO conjugates form nanoparticles, which accelerate cellular uptake and that the content of unsaturated fatty acids enhances endosomal escape. In an in vitro Duchenne muscular dystrophy exon skipping model using H2K‐mdx52 dystrophic skeletal myotubes, the highly potent PMO conjugates mediate significant splice‐switching at very low nanomolar concentrations. The presented aminoethylene‐lipopeptides are thus a promising platform for the generation of PMO‐therapeutics with a favorable activity/toxicity profile.     

Diffusion Magnetic Resonance Imaging-Based Biomarkers for Neurodegenerative Diseases

There has been an increasing prevalence of neurodegenerative diseases with the rapid increase in aging societies worldwide. Biomarkers that can be used to detect pathological changes before the development of severe neuronal loss and consequently facilitate early intervention with disease-modifying therapeutic modalities are therefore urgently needed. Diffusion magnetic resonance imaging (MRI) is a promising tool that can be used to infer microstructural characteristics of the brain, such as microstructural integrity and complexity, as well as axonal density, order, and myelination, through the utilization of water molecules that are diffused within the tissue, with displacement at the micron scale. Diffusion tensor imaging is the most commonly used diffusion MRI technique to assess the pathophysiology of neurodegenerative diseases. However, diffusion tensor imaging has several limitations, and new technologies, including neurite orientation dispersion and density imaging, diffusion kurtosis imaging, and free-water imaging, have been recently developed as approaches to overcome these constraints. This review provides an overview of these technologies and their potential as biomarkers for the early diagnosis and disease progression of major neurodegenerative diseases.     

Dynamic mechanical properties of three‐component composites (acrylic polymer/epoxy/SiO2) in the glass‐transition region

In previous studies, we reported the linear and nonlinear rheological properties of three‐component composites consisting of acrylic polymer (AP), epoxy resin (EP), and various SiO₂ contents (AP/EP/SiO₂) in the molten state. In this study, the dynamic mechanical properties of AP/EP/SiO₂ composites with different particle sizes (0.5 and 8 μm) were investigated in the glass‐transition region. The EP consisted of three kinds of EP components. The α relaxation due to the glass transition shifted to a higher temperature with an increase in the volume fraction (?) for the AP/EP/SiO₂ composites having a particle size of 0.5 μm, but the α relaxation scarcely shifted for the composite having a particle size of 8 μm as a general result. This result suggested that the SiO₂ nanoparticles that were 0.5 μm in size adsorbed a lot of the low‐glass‐transition‐temperature (T_g) component because of their large surface area. The AP/SiO₂ composites did not exhibit a shift in T_g; this indicated that the composite did not adsorb any component. The modulus in the glassy state (E′_g) exhibited a very weak &phis; dependence for the AP/EP/SiO₂ composites having particle sizes of 0.5 and 8 μm, although E′_g of the AP/SiO₂ composites increased with &phis;. The AP/EP/SiO₂ composites exhibited a peculiar dynamic mechanical behavior, although the AP/SiO₂ composites showed the behavior of general two‐component composites. Scanning electron microscopic observations indicated that some components in the EP were adsorbed on the surface of the SiO₂ particles. We concluded that the peculiar behavior of the AP/EP/SiO₂ composites was due to the selective adsorption of the EP component. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40409.     

取代聚苯乙炔环状三聚体的合成

以对溴苯酚为原料,经四步反应合成一种取代苯乙炔单体4-乙炔基-(2,6)二羟甲基-1-十二烷基酚醚。利用手性的铑催化剂引发聚合,得到高分子量的螺旋聚合物,通过GPC和CD对分子量和螺旋结构进行表征。最后通过光环化反应高效合成了环状三聚体,并通过1HNMR和GPC确认其化合物结构。     

Contribution of known endocrine disrupting substances to the estrogenic activity in Tama River water samples from Japan using instrumental analysis and in vitro reporter gene assay

To quantitatively characterize the substances contributing to estrogenic activity in river water, in vitro bioassay using MVLN cells and instrumental analysis using liquid chromatograph–mass spectrometer (LC/MS) or liquid chromatograph–tandem mass spectrometer (LC/MS/MS) were applied to river water extracts taken from various locations in the Tama River, Japan. Tama River water samples were extracted using solid phase extraction and the crude extracts were fractionated by high-performance liquid chromatography (HPLC) into 10 fractions. The sixth fraction contained nonylphenol (NP) and octylphenol (OP) at concentrations in the range of 51.6–147 and 6.9–81.9 ng/L, respectively (concentrations corresponding to the original sample volumes). No estrogenic activity, expressed as 17β-estradiol equivalents (E2-EQ_B), however, was observed in this fraction (<0.6 ng-E2eq/L). Instrumentally determined estrogenic activity (E2-EQ_C), which is the concentrations of NP and OP multiplied by their corresponding relative potency, was below the detection limit of the MVLN cell bioassay. Estrogenic activities were detected only in HPLC fraction nos. 7, 8 and 9. Estrone (E1), estradiol (E2) and bisphenol A (BPA) were detected in these fractions. Estriol (E3) and ethynylestradiol (EE2) were not detected (<0.2 ng/L) in these fractions. The calculated E2-EQ_C for BPA was below the detection limit of bioassay. The E2-EQ_C for E1 and E2 were on the same order as the estrogenic activity determined by the bioassay (E2-EQ_B). The ratios of E2-EQ_C and E2-EQ_B for E1 and E2 in the three factions collectively (nos. 7–9) were 0.49–0.97 and 0.29–1.12, respectively. Above results indicated that the major causal substances to the estrogenic activity in the Tama River were E1 and E2.     

基于价值评价方法对天津碱厂进行工业遗产的分级保护

工业遗产的价值评价、保护及再利用的方式成为目前的研究热点。基于价值评价法,对天津碱厂工业遗产的价值评价与工业遗产的实体相结合,探讨工业遗产的价值评价分级与分级保护方式,为工业遗产的保护和改造再利用方式提供理论依据。     

Recognition and Excision Properties of 8‐Halogenated‐7‐Deaza‐2′‐Deoxyguanosine as 8‐Oxo‐2′‐Deoxyguanosine Analogues and Fpg and hOGG1 Inhibitors

Cellular DNA continuously suffers various types of damage, and unrepaired damage increases disease progression risk. 8‐Oxo‐2′‐deoxyguanine (8‐oxo‐dG) is excised by repair enzymes, and their analogues are of interest as inhibitors and as bioprobes for study of these enzymes. We have developed 8‐halogenated‐7‐deaza‐2′‐deoxyguanosine derivatives that resemble 8‐oxo‐dG in that they adopt the syn conformation. In this study, we investigated their effects on Fpg (formamidopyrimidine DNA glycosylase) and hOGG1 (human 8‐oxoguanine DNA N‐glycosylase 1). Relative to 8‐oxo‐dG, Cl‐ and Br‐deaza‐dG were good substrates for Fpg, whereas they were less efficient substrates for hOGG1. Kinetics and binding experiments indicated that, although hOGG1 effectively binds Cl‐ and Br‐deaza‐dG analogues with low K_m values, their lower k_cat values result in low glycosylase activities. The benefits of the high binding affinities and low reactivities of 8‐oxo‐dG analogues with hOGG1 have been successfully applied to the competitive inhibition of the excision of 8‐oxoguanine from duplex DNA by hOGG1.