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

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

Cooling dynamics of self-assembled monolayer coating for integrated gold nanocrystals on a glass substrate

Picosecond time-resolved X-ray diffraction has been used to study the nanoscale thermal transportation dynamics of bare gold nanocrystals and thiol-based self-assembled monolayer (SAM)-coated integrated gold nanocrystals on a SiO$_2$ glass substrate. A temporal lattice expansion of 0.30-0.33% was observed in the bare and SAM-coated nanocrystals on the glass substrate; the thermal energy inside the gold nanocrystals was transported to the contacted substrate through the gold-SiO2 interface. The interfacial thermal conductivity between the single-layered gold nanocrystal film and the SiO$_2$ substrate is estimated to be 45 MW m$^{-2}$ K$^{-1}$ from the decay of the Au 111 peak shift, which was linearly dependent on the transient temperature. For the SAM-coated gold nanocrystals, the thermal dissipation was faster than that of the bare gold nanocrystal film. The thermal flow from the nanocrystals to the SAM-coated molecules promotes heat dissipation from the laser-heated SAM-coated gold nanocrystals. The thermal transportation of the laser-heated SAM-coated gold nanocrystal film was analyzed using the bidirectional thermal dissipation model