We have developed a new fluorescent sensing probe for double-stranded RNA (dsRNA) by integrating thiazole orange (TO) as a base surrogate into triplex-forming PNA. Our probe forms the thermally ...stable triplex with the target dsRNA at acidic pH; and the triplex formation is accompanied by the remarkable light-up response of the TO unit. The binding of our probe to the target dsRNA proceeds very rapidly, allowing real-time monitoring of the triplex formation. Importantly, we found the TO base surrogate in our probe functions as a universal base for the base pair opposite the TO unit in the triplex formation. Furthermore, the TO unit is significantly more responsive for the fully matched dsRNA sequence compared to the mismatch-containing sequences, which enables the analysis of the target dsRNA sequence at the single-base pair resolution. The binding and sensing functions of our probe are described for the development of fluorescent probes applicable to sensing biologically relevant dsRNA.
A series of triplex‐forming peptide nucleic acid (TFP) probes carrying a thiazole orange (TO) base surrogate through an alkyl linker was synthesized, and the interactions between these so‐called tFIT ...probes and purine‐rich sequences within double‐stranded RNA (dsRNA) were examined. We found that the TO base surrogate linker significantly affected both the binding affinity and the fluorescence response upon triplex formation with the target dsRNA. Among the probes examined, the TO base surrogate connected through the propyl linker in the tFIT probes increased the binding affinity by a factor of ten while maintaining its function as the fluorescent universal base. Isothermal titration calorimetry experiments revealed that the increased binding affinity resulted from the gain in the binding enthalpy, which could be explained by the enhanced π‐stacking interaction between the TO base surrogate and the dsRNA part of the triplex. We expect that these results will provide a molecular basis for designing strong binding tFIT probes for fluorescence sensing of various kinds of purine‐rich dsRNAs sequences including those carrying a pyrimidine‐purine inversion. The obtained data also offers a new insight into further development of the universal bases incorporated in TFP.
Enhanced recognition of double‐stranded RNA: Fluorescence sensing of double‐stranded RNA (dsRNA) by triplex‐forming PNA‐based probes carrying a thiazole orange base surrogate are enhanced by incorporation of the base surrogate linker. The binding affinity, selectivity for double‐strands over single‐strands, and the light‐up response were significantly improved.
Researchers around the world are developing technologies to minimize carbon dioxide emissions or carbon neutrality in various fields. In this study, the dry spinning of regenerated silk fibroin (RSF) ...was achieved as a proof of concept for a process using ionic liquids as dissolution aids and plasticizers in developing natural polymeric materials. A dry spinning equipment system combining a stainless-steel syringe and a brushless motor was built to generate fiber compacts from a dope of silk fibroin obtained by degumming silkworm silk cocoons and ionic liquid 1-hexyl-3-methyl-imidazolium chloride (HMIMCl) according to a general method. The maximum stress and maximum elongation of the RSF fibers were 159.9 MPa and 31.5%, respectively. RSF fibers containing ionic liquids have a homogeneous internal structure according to morphological investigations. Elemental analysis of fiber cross sections revealed the homogeneous distribution of nonvolatile ionic liquid HMIMCl in RSF fibers. Furthermore, the removal of ionic liquids from RSF fibers through impregnation washing with organic solvents was verified to enhance industrial applications. Tensile testing showed that the fiber strength could be maintained even after removing the ionic liquid. Thermogravimetric analysis results show that the organic solvent 1,1,1,3,3,3-hexafluoro-2-propanol is chemically coordinated to silk fibroin and, as a natural polymer, can withstand heat up to 250 °C.
We developed a new fluorescent peptide nucleic acid (PNA) probe, COT probe, capable of simultaneous recognition of 3'-overhang and double stranded sequences of target small interfering RNA (siRNA).
Application fields of supercapacitors are expanding because they have a very large charge/discharge current density and a cycle durability of tens of thousands of cycles or more compared to secondary ...batteries. There are various kinds of supercapacitor: electric double layer capacitors with a relatively long history, pseudocapacitors that utilize electrochemical reactions, and the progress of hybrid capacitor technology that combines double layer capacity and electrochemical reactions. Development of electrode materials and electrolytes and new cell design for constructing devices support the performance improvement and expansion of new applied fields such as automobiles, heavy machinery, and energy harvesting. This book aims to provide engineers with the opportunity to review the latest information by integrating cutting-edge papers on science, technology, and the application of supercapacitors.
•The visualization was performed from the side and bottom views.•The droplet height is much smaller than the boundary-layer thickness, and the droplet motions are strongly affected by turbulent shear ...flow.•The droplet oscillation frequencies were well predicted by the model based on the resonant vibrations of the standing waves except for the lower modes even in turbulent flow condition.•Based on the critical air velocity and droplet height, the motion onset was adequately approximated by a simple empirical relation between the Weber and Reynolds numbers.
Although numerous studies have investigated droplets in shear flows, the features of these droplets are incompletely understood. This paper reports our experimental visualization results of sessile droplets in fully developed turbulent shear flows and the onset of their movement. The visualization was performed from the side and bottom views. Furthermore, the droplet height is much smaller than the boundary-layer thickness, and the droplet motions are strongly affected by turbulent velocity fluctuation. The droplets were deformed toward the front and spread in a spanwise direction. The front and rear-side contact angles recover the balance position, that changes symmetrically over time and are not clearly related to sessile droplet oscillation. The droplet oscillation frequencies were well predicted by the model based on the resonant vibrations of the standing waves except for the lowest mode. Based on the critical air velocity and droplet height, the motion onset was adequately approximated by a simple empirical relation between the Weber and Reynolds numbers.
Immiscible composite materials with controlled phase-separated structures are important in areas ranging from catalysis to battery. We succeeded in controlling the phase-separated structures of ...immiscible blends of polystyrene (PS) and two ionic liquids (ILs), namely, N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium bis(trifluoromethylsulfonyl)imide (DEME-TFSI) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, by adding precisely designed concentrated polymer brush-grafted (CPB-grafted) silica nanoparticles (CPB-SiPs) prepared by surface-initiated atom-transfer radical polymerization. We discuss relationships between chemical species and molecular weights of the CPB and phase-separated structures. When the CPB was composed of a PS homopolymer of an appropriate molecular weight, the IL phase formed a continuous structure and a quasi-solid-blended film was successfully fabricated because the CPB-SiPs were adsorbed at the PS/IL interface and prevented macroscopic phase separation. We propose that CPB-SiP adsorption and the fabrication of quasi-solid films are governed by the degree of penetration of the matrix PS chains into the CPB and deformability of the CPB-SiPs. We found that the DEME-TFSI domain size can be controlled by the CPB-SiP content and that only 1 wt % of the CPB-SiPs was needed to fabricate a quasi-solid film. In addition, we investigated the ionic properties of the quasi-solid PS/DEME-TFSI-blended film. Owing to continuous ion channels composed only of DEME-TFSI, the film exhibited an ionic conductivity of 0.1 mS/cm, which is relatively high compared to previously reported quasi-solid electrolytes. Finally, we demonstrated that an electric double-layer capacitor fabricated using this film as the electrolyte exhibited high charge/discharge cycling stability and reversibility.
Nanopore pH sensing is based on the interaction between the surface charge of the nanopore and ions passing through the nanopore. The nanopore surface charge can be derived from the acid‐base ...dissociation equilibrium of the modified polyelectrolyte. Various polyelectrolytes have been selected based on the acid dissociation constant of the monomer units, and various techniques have been applied to modify nanopores. However, they have been developed without clear guidelines for characterizing the surface modification status or surface charge. One reason has been the difficulty in accurately estimating the surface charge of nanopores in solution. Thus, in this study, the dissociation constant (pKaapp) of the surface charge of a modified polyelectrolyte nanopore was quantitatively estimated via electrochemical measurements. Previously, the modification status of nanopores has been evaluated using the ion current response. In addition, we monitored in real‐time the polyelectrolyte modification status using a quartz crystal microbalance (QCM). Some polyelectrolytes were difficult to immobilize directly on the nanopore surface, and those polymers could be effectively modified by the layer‐by‐layer (LbL) technique. Therefore, we produced a guideline for the fabrication of a nanopore sensor for pH measurements under physiological conditions by quantitative evaluation of the pKaapp via electrochemical methods, the monitoring of the modification status by QCM, and the development of an effective modification method via the LbL technique.
Human joints support us to reduce the impact on our body and move them smoothly. As they are composed of gel-like structures, gel materials with soft and resilient properties are expected, as ...lubricants, to provide high efficiency and a long lifetime for mechanical parts. While double network gels including ionic liquids as swelling agents possess high mechanical strength and stable low friction under high temperature or vacuum, their fabrication process is complex and time-consuming. In this study, we applied one-pot synthesis to a double network ion gel (DNIG) to obtain a thin gel film by a simple coating method and examined its thermal, mechanical and tribological properties. The DNIG was obtained by one-pot synthesis (DNIG-1) combining polycondensation of tetraethoxysilane and radical polymerization of methyl methacrylate to form silica and poly(methyl methacrylate) as a 1st and 2nd network, respectively. Such obtained DNIG-1 was characterized and compared with DNIG obtained by a conventional two-step process (DNIG-2). Thermogravimetric analysis and the compressive stress-strain test showed high thermal stability and mechanical strength of DNIG-1. As friction at the glass/DNIG-1 interface showed high friction compared with that at glass/DNIG-2, various counterface materials were applied to examine their effect on the friction of DNIG-1. As SUS304/DNIG-1 showed much lower friction compared with glass/DNIG-1, the difference in the friction was presumably due to the different adsorption forces and compatibility between the materials.
Background
Biomarker for usefulness in diagnosing advanced fibrosis in nonalcoholic fatty liver disease (NAFLD) is expected. In order to discover novel biomarkers for NAFLD and its pathogenesis, we ...performed matabolomics screening.
Methods
(1) The initial cohort was 44 NAFLD patients. (2) This validation cohort was 105 NAFLD patients, 26 primary biliary cirrhosis (PBC) patients, and 48 healthy controls. Using capillary electrophoresis and liquid chromatography with mass spectrometry, we analyzed low molecular weight metabolites in these groups.
Results
1. In the initial cohort, we found 28 metabolites associated with advanced fibrosis. Among them, 4 sulfated steroids showed the greatest difference. A decrease of dehydroepiandrosterone sulfate (DHEA-S) and 5α-androstan-3β ol-17-one sulfate (etiocholanolone-S) was observed with the progression of fibrosis. Furthermore, 16 hydroxydehydroepiandrosterone sulfate (16-OH-DHEA-S) increased with the progression of fibrosis. 2. In the validation cohort, the decrease of DHEA-S and etiocholanolone-S, as well as the increase of 16-OH-DHEA-S, with the progression of fibrosis was confirmed. The 16-OH-DHEA-S/DHEA-S ratio and 16-OH-DHEA-S/etiocholanolone-S ratio were even more strongly associated with the grade of fibrosis. Among PBC patients, 16-OH-DHEA-S tended to be higher in stages 3 and 4 than in stages 1 and 2. However, levels of DHEA-S, etiocholanolone-S, and the two ratios were not associated with the stage of PBC.
Conclusion
Several metabolic products were found to be biomarkers of fibrosis in NAFLD and could also be useful for diagnosis of this condition. Our findings suggested disturbance of hormone metabolism in NAFLD and might lead to the development of new therapy.
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