Capturing molecular structural dynamics by 100 ps time-resolved X-ray absorption spectroscopy

An experimental set-up for time-resolved X-ray absorption spectroscopy with 100 ps time resolution at beamline NW14A at the Photon Factory Advanced Ring is presented

小学生のかつおだしと煮干しだしの風味に対する評価：食育取り組み年数が異なる2 校の比較

We compared evaluations of the flavors of dried bonito and niboshi extract soup stock for 5- 6 grade elementary school children（121 children）at two different schools. The two different schools were an elementary school that had implemented shokuiku（food and nutrition education）-related activities for 4 years（4th year school）and an elementary school that had implemented shokuiku-related activities for the first time（1st year school）. The results from fifth graders in elementary school showed that the deliciousness, umami taste, and aroma of both soup stocks（dried bonito and niboshi extract）were rated significantly higher in the 4th year school than in the 1st year school. In the 4th year school, several years of shokuiku-related activities may have increased the taste sensitivity of children to soup stock flavors.原著論

Size and Shape Controlled Crystallization of Hemoglobin for Advanced Crystallography

While high-throughput screening for protein crystallization conditions have rapidly evolved in the last few decades, it is also becoming increasingly necessary for the control of crystal size and shape as increasing diversity of protein crystallographic experiments. For example, X-ray crystallography (XRC) combined with photoexcitation and/or spectrophotometry requires optically thin but well diffracting crystals. By contrast, large-volume crystals are needed for weak signal experiments, such as neutron crystallography (NC) or recently developed X-ray fluorescent holography (XFH). In this article, we present, using hemoglobin as an example protein, some techniques for obtaining the crystals of controlled size, shape, and adequate quality. Furthermore, we describe a few case studies of applications of the optimized hemoglobin crystals for implementing the above mentioned crystallographic experiments, providing some hints and tips for the further progress of advanced protein crystallography

Giant Crystalline Molecular Rotors that Operate in the Solid State

Molecular motion in the solid state is typically precluded by the highly dense environment, and only molecules with a limited range of sizes show such dynamics. Here, we demonstrate the solid-state rotational motion of two giant molecules, i.e., triptycene and pentiptycene, by encapsulating a bulky N-heterocyclic carbene (NHC) Au(I) complex in the crystalline media. To date, triptycene is the largest molecule (surface area: 245 & ANGS;2; volume: 219 & ANGS;3) for which rotation has been reported in the solid state, with the largest rotational diameter among reported solid-state molecular rotors (9.5 & ANGS;). However, the pentiptycene rotator that is the subject of this study (surface area: 392 & ANGS;2; volume: 361 & ANGS;3; rotational diameter: 13.0 & ANGS;) surpasses this record. Single-crystal X-ray diffraction analyses of both the developed rotors revealed that these possess sufficient free volume around the rotator. The molecular motion in the solid state was confirmed using variable-temperature solid-state 2H spin-echo NMR studies. The triptycene rotor exhibited three-fold rotation, while temperature-dependent changes of the rotational angle were observed for the pentiptycene rotor. Here, we have described the first example of crystalline materials in which bulky iptycene derivatives (triptycene and pentiptycene) exhibit rotational dynamics in the solid state. It is revealed that encapsulation by a large concave NHC ligand provides reasonable rotational space around the central rotator. This platform will enable further design of systems in which large and complicated molecular units exhibit rotational motion in solid.imag

Vapochromic behaviour of a nickel(ii)-quinonoid complex with dimensional changes between 1D and higher

The nickel(ii)-chloranilato complex {Ni(ca)(VM)(2)}(n) (H(2)ca = chloranilic acid, VM = coordinated vapour molecules, such as water) shows reversible vapochromism upon exposure to various vapours and subsequent drying by heating. In contrast to the Ni(ii)-quinonoid complex, [Ni(HLMe)(2)] (H2LMe = 4-methylamino-6-methyliminio-3-oxocyclohexa-1,4-dien-1-olate), which was reported to exhibit vapochromic spin-state switching between high and low spin states, the chloranilato complex does not change its spin state even after the removal of coordinated vapour molecules. X-ray absorption fine structure (XAFS) analysis revealed that the six-coordinate geometry of {Ni(ca)(VM)(2)}(n) was maintained even after the removal of vapour molecules, in contrast to the [Ni(HLMe)(2)] complex. The unique vapochromism that follows the dimensional change between 1D and higher is influenced by the relatively weaker ligand field of the chloranilate ligand