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1.
Meccanica - The static deformation of symmetric bow limbs has been widely studied in the last century. However, asymmetries in shape and length which correspond to a more realistic situation, have... 相似文献
2.
Takashi Yoshimoto Prof. Dr. Hisako Hashimoto Dr. Nozomi Takagi Prof. Dr. Shigeyoshi Sakaki Naoki Hayakawa Dr. Tsukasa Matsuo Prof. Dr. Hiromi Tobita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(15):3795-3798
A tungsten silylyne complex having a W≡Si triple bond reacted with two molecules of aldehydes at room temperature to give W−Si−O−C four-membered metallacycles by [2+2] cycloaddition and subsequent formyl hydrogen transfer from one aldehyde molecule to another. Upon heating to 70 °C, the four-membered metallacycles underwent metathesis-like fragmentation cleanly to afford carbyne complexes and “silanoic esters,” in a manner similar to that of metallacyclobutadiene, an intermediate of alkyne metathesis reactions, and dimerization of the latter products gave 1,3-cyclodisiloxanes. The “silanoic ester” was also trapped by pivalaldehyde to give a [2+2] cycloaddition product in high yield. 相似文献
3.
Taito Hashimoto Dr. Ryusei Oketani Masaki Nobuoka Prof. Dr. Shu Seki Prof. Dr. Ichiro Hisaki 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2023,135(1):e202215836
Porous frameworks composed of non-stoichiometrically mixed multicomponent molecules attract much attention from a functional viewpoint. However, their designed preparation and precise structural characterization remain challenging. Herein, we demonstrate that cocrystallization of tetrakis(4-carboxyphenyl)hexahydropyrene and pyrene derivatives ( CP-Hp and CP-Py , respectively) yields non-stoichiometric mixed frameworks through networking via hydrogen bonding. The composition ratio of CP-Hp and CP-Py in the framework was determined by single crystalline X-ray crystallographic analysis, indicating that the mixed frameworks were formed over a wide range of composition ratios. Furthermore, microscopic Raman spectroscopy on the single crystal indicates that the components are not uniformly distributed such as ideal solid solution, but are done gradationally or inhomogeneously. 相似文献
4.
Takahiro Takayama Toshiki Mochizuki Kenichiro Todoroki Jun Zhe Min Hajime Mizuno Koichi Inoue Hiroyasu Akatsu Ichiro Noge Toshimasa Toyo'oka 《Analytica chimica acta》2015
Chiral metabolites are found in a wide variety of living organisms and some of them are understood to be physiologically active compounds and biomarkers. However, the overall analysis of chiral metabolomics is quite difficult due to the high number of metabolites, the significant diversity in their physicochemical properties, and concentration range from metabolite-to-metabolite. To solve this difficulty, we developed a novel approach for chiral metabolomics fingerprinting and chiral metabolomics extraction, which is based on the labeling of a pair of enantiomers of chiral derivatization reagents (i.e., DMT-(S,R)-Pro-OSu and DMT-3(S,R)-Apy) and precursor ion scan chromatography of the derivatives. The multivariate statistics is also required for this strategy. The proposed procedures were evaluated by the detection of a diagnostic marker (i.e., d-lactic acid) using the saliva of diabetic patients. This method was used for the determination of biomarker candidates of chiral amines and carboxyls in Alzheimer's disease (AD) brain homogenates. As the results, l-phenylalanine (L-Phe) and l-lactic acid (L-LA) were identified as the decreased and increased biomarker candidates in the AD brain, respectively. Therefore, the proposed approach seems to be helpful for the determination of non-target chiral metabolomics possessing amines and carboxyls. 相似文献
5.
Ichiro Hisaki Shoichi Nakagawa Norimitsu Tohnai Mikiji Miyata 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(10):3051-3055
A C3‐symmetric π‐conjugated macrocycle combined with an appropriate hydrogen bonding module (phenylene triangle) allowed the construction of crystalline supramolecular frameworks with a cavity volume of up to 58 %. The frameworks were obtained through non‐interpenetrated stacking of a hexagonal sheet possessing three kinds of pores with different sizes and shapes. The activated porous material absorbed CO2 up to 96 cm3 g−1 at 195 K under 1 atm. 相似文献
6.
Dr. Neil J. Stewart Hitomi Nakano Shuto Sugai Mitsushi Tomohiro Yuki Kase Yoshiki Uchio Dr. Toru Yamaguchi Yujirou Matsuo Dr. Tatsuya Naganuma Dr. Norihiko Takeda Dr. Ikuya Nishimura Dr. Hiroshi Hirata Dr. Takuya Hashimoto Dr. Shingo Matsumoto 《Chemphyschem》2021,22(10):915-923
Hyperpolarized [1-13C]fumarate is a promising magnetic resonance imaging (MRI) biomarker for cellular necrosis, which plays an important role in various disease and cancerous pathological processes. To demonstrate the feasibility of MRI of [1-13C]fumarate metabolism using parahydrogen-induced polarization (PHIP), a low-cost alternative to dissolution dynamic nuclear polarization (dDNP), a cost-effective and high-yield synthetic pathway of hydrogenation precursor [1-13C]acetylenedicarboxylate (ADC) was developed. The trans-selectivity of the hydrogenation reaction of ADC using a ruthenium-based catalyst was elucidated employing density functional theory (DFT) simulations. A simple PHIP set-up was used to generate hyperpolarized [1-13C]fumarate at sufficient 13C polarization for ex vivo detection of hyperpolarized 13C malate metabolized from fumarate in murine liver tissue homogenates, and in vivo 13C MR spectroscopy and imaging in a murine model of acetaminophen-induced hepatitis. 相似文献
7.
The present numerical study has dealt with the enhancement of latent heat Release by using plate type fins mounted on the vertical cooling surface in the rectangular vessel packed with molten salt as a latent heat storage material. It was found that the fin thickness and pitch exerted an influence on solidification heat transfer in a liquid layer of a nitric molten salt. The numerical results elucidated the flow pattern, velocity profile and heat transfer rate in the melted liquid layer. 相似文献
8.
A great number of experimental data indicating shock wave/boundary layer interactions in internal or external supersonic flows
were reviewed to make clear the mechanism of the interaction and to decide the onset of shock-induced separation. The interesting
conclusions were obtained for the considerably wide range of flow geometries that the onset of separation is independent of
the flow geometries and the boundary layer Reynolds number. It is found that the pressure rise necessary to separate the boundary
layer in supersonic external flows could be applied to such internal flows as overexpanded nozzles or diffusers. This is due
to the fact that the separation phenomenon caused by shock wave/boundary layer interactions is processed through a supersonic
deceleration. The shock-induced separation in almost all of interacting flow fields is governed by the concept of free interaction,
and the onset of shock-induced separation is only a function of the Mach number just upstream of shock wave. However, physical
scales of the produced separation are not independent of the downstream flow fields. 相似文献
9.
Emiko Igarashi Kenta Sakamoto Tomoyuki Yoshimura Jun-ichi Matsuo 《Tetrahedron letters》2019,60(1):13-15
Various 3-phenylcyclobutanones reacted with aliphatic and aromatic nitriles in the presence of Me3SiOTf to afford dihydropyridones by formal [4+2] cycloaddition. 相似文献
10.
Dr. Yoshifumi Sasano Dr. Yohei Haketa Hiroki Tanaka Dr. Nobuhiro Yasuda Prof. Ichiro Hisaki Prof. Hiromitsu Maeda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(27):6712-6717
Phenyl groups were introduced at the β-positions proximal to the meso-hydroxy moiety in hydroxyporphyrin NiII complexes by oxidized BINAP PdII complexes. Ion-pairing assemblies of deprotonated π-electronic anions, anionic site of which was stabilized by the introduced phenyl moieties with a bulky cation, were formed. They showed charge-by-charge assemblies, assembly modes of which were modulated by the anionic building units. 相似文献