A5031815941- Microbial Natural Products and Biosynthesis
- Gamma-ray bursts and supernovae
- Marine Sponges and Natural Products
- Carbohydrate Chemistry and Synthesis
- Molecular spectroscopy and chirality
- Synthetic Organic Chemistry Methods
- Robotic Mechanisms and Dynamics
- Phytochemistry and Biological Activities
- Chemical synthesis and alkaloids
- Asymmetric Synthesis and Catalysis
- Natural product bioactivities and synthesis
- Robot Manipulation and Learning
- Robotic Locomotion and Control
- Nuclear physics research studies
- Advanced machining processes and optimization
- Oxidative Organic Chemistry Reactions
- Synthesis and Catalytic Reactions
- Analytical Chemistry and Chromatography
- Iterative Learning Control Systems
- Pulsars and Gravitational Waves Research
- Fungal Biology and Applications
- Glycosylation and Glycoproteins Research
- Cyclopropane Reaction Mechanisms
- Cosmology and Gravitation Theories
- Traditional and Medicinal Uses of Annonaceae
Hirosaki University
2016-2025
Iwate University
2002-2025
Hyogo University
2023
National Center for Global Health and Medicine
2022
European Foundation for the Study of Chronic Liver Failure
2021
Tokyo University of Science
1979-2019
Mimasaka University
2018
Ōtani University
2001-2017
The Cancer Institute Hospital
2012-2016
Japanese Foundation For Cancer Research
2012-2016
Age-related macular degeneration, a major cause of blindness for which no satisfactory treatments exist, leads to gradual decrease in central high acuity vision. The accumulation fluorescent materials, called lipofuscin, retinal pigment epithelial cells the aging retina is most pronounced macula. One fluorophores lipofuscin has been characterized as A2E, pyridinium bis-retinoid, derived from two molecules vitamin A aldehyde and one molecule ethanolamine. An investigation aimed at optimizing...
The predicted nucleosynthesis products of Type Ia and II supernovae are combined with various parameter ratios compared the solar abundances heavy elements their isotopes, also in LMC SMC. Aided by a reasonable model galactic chemical evolution, ratio total numbers (of all time) to that best reproduces observed is determined be NIa/NII = 0.15 for Galaxy, agreement current observations. For MCs, however, this larger than yielding 0.2–0.3. We discuss several possible star formation history...
The stable nuclear shape in very dense matter composed of protons, neutrons and electrons is investigated. It shown that, as the density increases from 1013 to 1014.5g cm−3, likely change successively sphere cylinder, board, cylindrical hole spherical before uniform neutron-star formed.
An efficient protocol for calculating 13C NMR chemical shifts natural products with multiple degrees of conformational freedom is described. This involves a multistep procedure starting from molecular mechanics and ending large basis set density functional model to obtain accurate Boltzmann conformer weights, followed by empirically corrected calculations the individual conformers. The accuracy (average rms <4 ppm) was determined application ∼925 diverse products, structures which have been...
The authors propose a joint torque sensing technique making use of the existing structural elasticity robots. provides without reducing stiffness robot or changing mechanical structure joints. flexsplines harmonic drives is utilized to measure torque. are flexible thin cups, made from steel, in that driven by wave generators. A finite-element analysis shows special configuration strain gauges, mounted on flexspline, has be employed eliminate errors sensor information due rotation generator....
A new method based on NMR spectroscopy is introduced to determine the absolute configuration of natural compounds and has been successfully applied sucro-neolambertellin. The relies measurement residual dipolar couplings (RDCs), which allow unknown stereocenters be related with known (see picture). approach used D-threo-2,5-hexodiulofuranose moiety by relating it α-D-glucose.
Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA) is a membrane protein on the endoplasmic (ER) that transports Ca2+ from cytosol into ER. As its function associated with various biological phenomena, SERCA has been recognized as promising druggable target. Here, we report second-strongest SERCA-inhibitory compound known to date, which isolated marine cyanobacterium Leptochromothrix valpauliae and named iezoside (1). The structure of (1) fundamentally different any other inhibitor, potency...
An azaphilone, 6,7-iso-felinone A (2), was isolated from Diaporthales sp. KT3922 along with the known felinone (1). While compound 2 exhibited weak Cotton effects, its naphthoate derivative (2a) displayed pronounced enabling determination of absolute configuration through electronic circular dichroism (ECD) spectral analysis. Interestingly, spectroscopically derived relative structure proved identical to previously reported hypoillexidiol (3) and xylariphilone (4). However, substantial...
Presupernova models and nucleosynthesis in massive stars are reviewed the context of supernovae. First, presupernova evolutionary toward onset collapse from 13 to 70 M⊙ main-sequence stage presented. It is stressed that silicon ("Si") shell burning key point determine final size iron core. As result, we obtain core ranges 1.2 1.9 for 13–70 stars. Silicon-rich layers boundary between "Si" oxygen-rich neutronized during burning. The s-process helium investigated detail whole found weak...
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTotal syntheses of (+)-thyrsiferol, (+)-thyrsiferyl 23-acetate, and (+)-venustatriolMasaru Hashimoto, Toshiyuki Kan, Koji Nozaki, Mitsutoshi Yanagiya, Haruhisa Shirahama, Takeshi MatsumotoCite this: J. Org. Chem. 1990, 55, 17, 5088–5107Publication Date (Print):August 1, 1990Publication History Published online1 May 2002Published inissue 1 August 1990https://pubs.acs.org/doi/10.1021/jo00304a022https://doi.org/10.1021/jo00304a022research-articleACS...
Fluorescent bisretinoid compounds accumulate in retinal pigment epithelial (RPE) cells as a consequence of two processes: random reactions vitamin A aldehyde photoreceptor cell outer segments, and phagocytosis discarded segment discs by RPE. The formation is accentuated some forms degeneration. detection novel fluorophore that conjugate all-trans-retinal glycerophosphoethanolamine reported.Human RPE/choroid, eyes harvested from Abca4 (ATP-binding cassette transporter 4) null mutant mice,...
A refined argument is given which strengthens the previous conclusions that stable "nuclear" shape in high-density matter successively changes from sphere to cylinder, board cylindrical hole and spherical as density of increases neighborhood 1014 g/cm3.
Optically active sydonic acid (1) was isolated for the first time from a culture broth of Glonium sp. The absolute stereochemistry established to be (S) by comparing circular dichroism (CD) spectrum with that (+)-curcutetraol after conversion into (+)-sydonol (2).
Two new metabolites, (R)-3,4-dihydro-4,6,8-trihydroxy-4,5-dimethyl-3-methyleneisochromen-1-one (1) and (R)-7-hydroxy-3-((S)-1-hydroxyethyl)-5-methoxy-3,4-dimethylisobenzofuran-1(3H)-one (2), were isolated along with two structurally known related compounds (3 4) from the culture broth of Leptosphaeria sp. KTC 727 (JCM 13076 = MAFF 239586). These structures disclosed mainly 1H 13C NMR spectroscopic analyses. The relative configuration 2 was established by NOE studies. absolute this molecule...
Neomacrophorin X (1) was isolated from Trichoderma sp. 1212-03. Heteronuclear multiple bond correlation (HMBC) spectral analysis indicated a unique [4.4.3]propellane framework, which verified by the 1H and 13C chemical shift calculations based on density functional theory (DFT) subsequent comparison with experimental data obtained in CDCl3. The DFT-based electronic circular dichroism (ECD) were effective not only determining absolute configuration but also confirming relative structure....
Twelve high schools in Japan (of which six are Fukushima Prefecture), four France, eight Poland and two Belarus cooperated the measurement comparison of individual external doses 2014. In total 216 high-school students teachers participated study. Each participant wore an electronic personal dosimeter "D-shuttle" for weeks, kept a journal his/her whereabouts activities. The distributions annual estimated each region overlap with other, demonstrating that locations where residence is...
Helminthosporium velutinum yone96 produces cyclohelminthol X (1), a unique hexa-substituted spirocyclopropane. Although its molecular formula and NMR spectral data resemble those of AD0157, being isolated from marine fungus Paraconiothyrium sp. HL-78-gCHSP3-B005, our detailed analyses disclosed totally different structure. Chemical shift calculations electronic circular dichroism were quite helpful to establish the structure, when performed based on density functional theory. The carbon...
The synthesis of chiral, nonracemic difluoromethylthio (SCF2H) compounds that contain a tetrasubstituted stereogenic center is reported. Racemic α-SCF2H-β-ketoallylesters 5 were initially prepared by an electrophilic difluoromethylthiolation β-ketoallylesters 6, followed Pd-catalyzed Tsuji decarboxylative asymmetric allylic alkylation (DAAA) to provide wide variety α-allyl-α-SCF2H-ketones (4) with high enantiopurity. This strategy can be extended the enantioselective...
Paraphaeoketones A–C (1–3) were isolated from the culture broth of Paraphaeosphaeria sp. KT4192. Their structures and relative configurations determined using spectroscopic analysis verified through density functional theory (DFT)-based chemical shift calculations. The absolute these compounds by comparing experimental electronic circular dichroism (ECD) spectra with those based on DFT We also propose a plausible biosynthetic route to 1–3. While our prior studies isolation structural...