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Flavan-3-ols, flavonoids, anthocyanidins and triterpenoids induces TIE2 phosphorylation -a candidate target for the vascular protective effects
No full textVascular system is essential for the body to maintain health. Dysregulated vascular system leads to cardiovascular diseases and are observed in ischaemic stroke, Alzheimer's disease, amyotrophic lateral sclerosis, and diabetes. TIE2 is a tyrosine kinase receptor expressed on vascular endothelial cells and contributes to the maintenance of a vascular system. In this paper, we screened for natural products with an activity to induce phosphorylation of TIE2, which will be beneficial for protection of a vascular system. Employing HeLa cells expressing TIE2, flavan-3-ols, flavonoids, anthocyanidins and triterpenoids were identified as active compounds that induce TIE2 phosphorylation. Several of the identified compounds are previously reported to protect endothelial cells from inflammation. Thus, the result provided TIE2 as the candidate receptor protein of those compounds for the protective effect of endothelial cells and the identified compounds will be a good candidate for maintenance of a vascular system
A quartz crystal microbalance with dissipation monitoring of dehydrogenative copolymerization of coniferyl alcohol and sinapyl alcohol
No full textDehydrogenation polymers (DHPs) can be prepared from coniferyl alcohol (CA), but not solely from sinapyl alcohol (SA) when catalyzed by horseradish peroxidase (HRP). However, it has been proven that from a mixture of CA and SA, DHP with SA incorporated can be formed even with HRP. Conventional experiments using this mixed monolignol system required large amounts of monolignols and enzymes. The use of a quartz crystal microbalance with dissipation (QCM-D) can overcome this drawback. In this study, the dehydrogenative copolymerization of small amounts of CA/SA mixtures and HRP was performed on a QCM-D to further explore the benefits of this system. The DHPs were successfully formed from mixed monolignols on the QCM-D system, and the incorporation of the SA unit was verified through differences in DHP formation between binary monolignol systems and the corresponding CA-single systems. The formation of DHP in the presence of the polysaccharide matrix was performed at the same reaction scale, and the promotional effect of partially acetylated xylan on DHP formation was observed, especially at high CA ratios. The QCM-D monitoring system will be a valuable tool for analyses under limited substrates and/or enzymes that may be encountered in the future
高発光効率セシウムスズハライドペロブスカイトナノ粒子の合成
No full textColloidal halide perovskite nanocrystals (NCs) have garnered substantial attention in recent years due to their excellent optoelectronic properties, which include tunable bandgaps, high photoluminescence efficiency, and substantial absorption coefficients. These attributes have propelled their widespread utilization across diverse optoelectronic applications, including lasers, light-emitting diodes, and solar cells. However, with the growing interest in using metal halide perovskite for optoelectronic devices, concerns about the toxicity of lead in lead-based halide perovskite materials make it necessary to look for lead-free alternatives. Tin halide perovskites have emerged as promising substitutes owing to their reduced toxicity and comparable perovskite-like characteristics. Nonetheless, the synthesis of high-quality colloidal CsSnX3 (X= Cl, Br, I) perovskite NCs presents a formidable challenge, impeding their widespread adoption in next-generation optoelectronic applications. This thesis delves into the synthesis mechanism and precursor chemistry governing the formation of tin halide perovskite NCs, culminating in the development of effective synthetic methodologies conducive to yielding high-quality products. Chapter 1 provides an introduction to the research background of metal halide perovskite materials, including synthetic methods for metal halide perovskites, and summarizes the effective strategies reported to enhance the optical properties of metal halide perovskite materials. Additionally, it outlines the research progress of tin-based halide perovskite NCs. Finally, it elucidates the research topic's conceptual framework. In chapter 2, the investigation focuses on elucidating the precursor chemistry involved in the hot-injection synthesis method for representative tin halide perovskite NCs, particularly CsSnI3 NCs. Through comprehensive analysis, including nuclear magnetic resonance (NMR) spectroscopy, significant insights are gleaned regarding the role of polymeric alkanoate iodides, formed as intermediate products during the reaction between tin and iodide precursors, in modulating NCs properties such as photoluminescence quantum yield (PLQY), size, morphology, and uniformity. In chapter 3, straightforward method based on ion exchange is proposed, showcasing its effectiveness in generating high-quality CsSnX3 NCs with excellent PLQY and adjustable size. CsSnI3 NCs with a remarkable PLQY of 34.4% were obtained, surpassing the previously reported maximum value of 18.4%. The controlled reaction kinetics inherent in this approach enable the synthesis of NCs with excellent size uniformity, crucial for optoelectronic applications. In chapter 4, further exploration into controlled ion exchange processes, facilitated by incorporating an additional tin source during the synthesis of CsSnI3 NCs, unveils a pathway to enhance crystal quality. This endeavor resulted in a significant enhancement of the PLQY of CsSnI3 NCs to 49.7%, accompanied by uniform size distribution. In-depth analysis, including in-situ photoluminescence (PL) and high-resolution transmission electron microscopy (HRTEM), elucidates the role of the additional tin source in accelerating the reaction rate that minimizes uncoordinated Sn and I atoms and thus boosts the PLQY of CsSnI3 NCs. Additionally, the versatility of this methods is demonstrated through the synthesis of tin halide perovskite NCs with varied halide compositions. In summary, this thesis advances the understanding of synthesis strategies for high-quality tin halide perovskite NCs, offering valuable insights into precursor chemistry, reaction mechanisms, and synthetic methodologies. The developed approaches hold immense potential for facilitating the widespread utilization of tin halide perovskite NCs in diverse optoelectronic applications, thereby propelling the evolution of next-generation optoelectronic devices
Preoperative risk factors for skeletal muscle mass loss in patients with biliary tract cancer
No full textBackground Endoscopic retrograde cholangiography (ERC)-related procedures, usually performed before biliary tract cancer (BTC) surgery, are associated with increased risk for various complications, which can cause sarcopenia. No study has previously elucidated the relationship between preoperative ERC-related procedures and sarcopenia/skeletal muscle mass loss. Methods Patients with BTC who underwent radical surgical resection following ERC-related procedures were included. Skeletal muscle mass was evaluated using the psoas muscle mass index (PMI), which was determined using computed tomography images, and the change in PMI before the initial pre-ERC and surgery (ΔPMI) was calculated. Risk factors for advanced skeletal muscle mass loss, defined as a large ΔPMI, were evaluated. Results The study cohort included 90 patients with a median age of 72 (interquartile range, 65–75) years. The median PMI pre-ERC and surgery was 4.40 and 4.15 cm2/m2, respectively (p < .01). The median ΔPMI was −6.2% (interquartile range, −10.9% to 0.5%). By multivariate analysis, post-ERC pancreatitis and cholangitis before surgery were independent predictive factors for large PMI loss (odds ratio, 4.57 and 3.18, respectively; p = .03 and p = .02, respectively). Conclusions Skeletal muscle mass decreases preoperatively in most patients with BTC undergoing ERC. Post-ERC pancreatitis and cholangitis before surgery were independent risk factors for large skeletal muscle mass loss
Macroscopic and microscopic morphological characteristics of gelatinous egg masses (egg veils) of yellow goosefish Lophius litulon (Lophiiformes; Lophiidae)
No full textWe recorded the morphological characteristics and effect of preservation methods on the structure of the egg veils of Lophius litulon found in field investigations. The egg veils were characterised as translucent sheet-shape with parallel opaque creases spaced approximately 2 cm apart. The egg veils were found to be composed of pentagonal or hexagonal chambers with rounded corners arranged in one layer, and each chamber enveloped one to three embryos. Cryopreservation is recommended to prevent structural changes in the egg veil rather than ethanol solution and neutral buffered formalin solution
Molecular mechanism for the substrate specificity of Arthrobacter globiformis M6 α-glucosidase CmmB, belonging to glycoside hydrolase family 13 subfamily 30
No full textalpha-Glucosidase hydrolyzes alpha-D-glucosides to produce alpha-D-glucose. Glycoside hydrolase family 13 (GH13) contains alpha-glucosidases together with various amylolytic enzymes. GH13 alpha-glucosidases fall into several distinct subfamilies, and subfamily 30 (GH13_30) includes numerous Actinomycetes alpha-glucosidases. GH13_30 alpha-glucosidase CmmB from Arthrobacter globiformis, specific to maltooligosaccharides, is involved in the intracellular metabolism of cyclobis-(1 -> 6)-alpha-maltosyl. Herein, the function and structure of CmmB were investigated to advance understanding of the structure-function relationship. CmmB showed the highest kcat/Km for maltose of maltooligosaccharides, and kcat/Km drastically decreased with increasing substrate chain-length. The crystal structures of CmmB in complex with a pseudodisaccharide (acarviosin) and pseudotetrasaccharide (acarbose) were determined at resolutions of 1.60 and 1.70 & Aring;, respectively. The overall structure of CmmB was typical of a GH13 alpha-glucosidase. Most of the structure of the beta ->alpha loop 7 of the catalytic (beta/alpha)8-barrel domain was not determined in the acarbose complex, but the C-terminal side of this loop was modeled in the acarviosin complex. For binding to acarviosin, this loop took on a closed conformation, and I360 and R364 on this loop formed subsite +1 together with H224 and W280. Alanine substitution of these residues indicated that R364 was essential for the catalysis through a hydrogen bond with the O6 of the D-glucose residue in subsite +1. The beta ->alpha loop 7 is flexible upon binding to substrates, but I360 and R364 cannot participate in binding to maltooligosaccharides longer than maltose. The loss of interactions with these residues was concluded to result in the low preference for maltotriose and longer maltooligosaccharides
Boron-Catalyzed Michael Reaction of Donor-Acceptor Carboxylic Acid Pairs Enabling Direct Synthesis of 1,5-Dicarboxylic Acids
No full textA boron-catalyzed Michael reaction using pairs of carboxylic acids was developed. The reaction occurs through dual activation of the two substrates by a boron catalyst, which facilitates boron enolate formation from the donor carboxylic acid with simultaneous activation of the alpha,beta-unsaturated carboxylic acid as the acceptor. alpha-Aryl and alpha-alkenyl carboxylic acids were applicable as donors. The versatility and utility of this reaction were demonstrated by the direct use of pharmaceuticals as donor carboxylic acids
Scattering of solutions with group invariance for the fourth-order nonlinear Schrödinger equation
No full textIn this paper, we consider the focusing, L 2-supercritical and H (center dot) 2 -subcritical fourth-order nonlinear Schr & ouml;dinger equations. We show the scattering of group-invariant solutions below the ground state threshold, under the hypothesis that the threshold for group-invariant solutions is less than a certain value
Photoswitchable Auxin-Inducible Degron System for Conditional Protein Degradation with Spatiotemporal Resolution
No full textThe auxin-inducible degron (AID) system degrades target proteins rapidly in a controllable manner. Although this is a highly versatile technique for studying protein functionality, protein degradation with spatiotemporal resolution is not currently possible. Herein we describe a photoswitchable AID using a light-active auxin derivative for reversible and site-specific protein degradation with temporal resolution
Average Cubic BaTaO2N Crystal Structure Formed by 50 nm Size Domains with Polar Nanoregions Consisting of cis-TaO4N2 Octahedral Chains
No full textA noncentrosymmetric polar structure in ferroelectric BaTaO2N having a cubic perovskite-type structure was investigated both in theoretical calculation and experimental observations. The most probable coordination around Ta was confirmed to be cis-TaO4N2 in exhaustive energy calculations about the O and N atomic distribution. The cis-TaO4N2 octahedra formed their local stackings during cooling of BaTaO2N melt at 1183 K. Their linkages precipitate as nanosize units forming domains in approximately 50 nm individually having spontaneous polarization as observed in integrated differential phase contrast-scanning transmission electron microscopy. They were observed in a noncentrosymmetric structure with polar space group Pmc2(1) detected in Raman spectroscopy and supported by the theoretical calculations to form nanopolar regions. The polar nanoregions were three-dimensionally averaged as a centrosymmetric crystal structure in cubic space group Pm3m observed in neutron diffraction. The nanoregions in Pmc2(1) were quenched at room temperature to show their relaxor-type ferroelectricity in the average Pm3m structure