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Journal Articles

Local structure of rare earth elements (REE) in marine ferromanganese oxides by extended X-ray absorption fine structure and its comparison with REE in ion-adsorption type deposits

Nagasawa, Makoto*; Qin, H.-B.*; Yamaguchi, Akiko; Takahashi, Yoshio*

Chemistry Letters, 49(8), p.909 - 911, 2020/08

 Times Cited Count:0 Percentile:100(Chemistry, Multidisciplinary)

Journal Articles

Nanostructural characterization of oleyl acid phosphate in poly-$$alpha$$-olefin using small-angle X-ray scattering

Oba, Yojiro; Motokawa, Ryuhei; Hino, Masahiro*; Adachi, Nozomu*; Todaka, Yoshikazu*; Inoue, Rintaro*; Sugiyama, Masaaki*

Chemistry Letters, 49(7), p.823 - 825, 2020/07

 Times Cited Count:0 Percentile:100(Chemistry, Multidisciplinary)

Journal Articles

Bromine-isotope selective ionization using field-free alignment of IBr isotopologues with a switched nanosecond laser pulse

Akagi, Hiroshi*; Kumada, Takayuki; Otobe, Tomohito*; Itakura, Ryuji*; Hasegawa, Hirokazu*; Oshima, Yasuhiro*

Chemistry Letters, 49(4), p.416 - 418, 2020/04

 Times Cited Count:0 Percentile:100(Chemistry, Multidisciplinary)

Journal Articles

Segmental motions of proteins under non-native states evaluated using quasielastic neutron scattering

Fujiwara, Satoru*; Matsuo, Tatsuhito*; Sugimoto, Yasunobu*; Shibata, Kaoru

Journal of Physical Chemistry Letters (Internet), 10(23), p.7505 - 7509, 2019/12

 Times Cited Count:0 Percentile:100(Chemistry, Physical)

Characterization of the dynamics of disordered polypeptide chains is required to elucidate the behavior of intrinsically disordered proteins and proteins under non-native states related to the folding process. Here we develop a method using quasielastic neutron scattering, combined with small-angle X-ray scattering and dynamic light scattering, to evaluate segmental motions of proteins as well as diffusion of the entire molecules and local side-chain motions. We apply this method to RNase A under the unfolded and molten-globule (MG) states. The diffusion coefficients arising from the segmental motions are evaluated and found to be different between the unfolded and MG states. The values obtained here are consistent with those obtained using the fluorescence-based techniques. These results demonstrate not only feasibility of this method but also usefulness to characterize the behavior of proteins under various disordered states.

Journal Articles

Finding free-energy landmarks of chemical reactions

Shiga, Motoyuki; Tuckerman, M. E.*

Journal of Physical Chemistry Letters (Internet), 9(21), p.6207 - 6214, 2018/11

 Times Cited Count:3 Percentile:78.62(Chemistry, Physical)

Predicting reaction pathways is one of the most important goals in theoretical and computational chemistry. In this paper, we propose a novel approach to search for free-energy landmarks, i.e., minima and the saddle points, of chemical reactions in an automated manner using a combination of steepest descent and gentlest ascent methods. As demonstrations, we present applications to the ring-opening reaction of benzocyclobutene and an SN2 reaction in aqueous solution.

Journal Articles

Rechargeable batteries based on stable redox reactions of disulfide included in a metal-organic framework as ligands

Shimizu, Takeshi*; Wang, H.*; Tanifuji, Naoki*; Matsumura, Daiju; Yoshimura, Masashi*; Nakanishi, Koji*; Ota, Toshiaki*; Yoshikawa, Hirofumi*

Chemistry Letters, 47(5), p.678 - 681, 2018/05

 Times Cited Count:3 Percentile:70.3(Chemistry, Multidisciplinary)

Journal Articles

Sorption behavior of Np(V) on microbe pure culture and consortia

Onuki, Toshihiko; Kozai, Naofumi; Sakamoto, Fuminori; Utsunomiya, Satoshi*; Kato, Kenji*

Chemistry Letters, 46(5), p.771 - 774, 2017/05

 Times Cited Count:0 Percentile:100(Chemistry, Multidisciplinary)

The sorption behavior of Np(V) by the microbe consortia and by a single pure culture of Fe reducing bacterium was studied at pH between 3 and 7 in resting cell conditions. The sorption of Np(V) by the Fe reducing bacterium obtained in the inert condition and by the consortia in aerated condition were higher than by the Fe reducing bacterium in aerobic condition at pH below 5, strongly suggesting presence of other mechanism than the adsorption on microbial cell surface, i.e. reduction to Np(IV).

Journal Articles

Efficient adsorption of Rh(III) from HNO$$_{3}$$ solution on ion-exchange resin bearing ${it N,N,N}$-trimethylglycine by adding N donor ligands and desorption using thiourea

Suzuki, Tomoya; Morita, Keisuke; Sasaki, Yuji

Chemistry Letters, 44(2), p.152 - 153, 2015/02

 Times Cited Count:2 Percentile:88.4(Chemistry, Multidisciplinary)

To recover Rh(III) from HNO$$_{3}$$ solution, adsorption experiments have been performed using an ion-exchange resin bearing an ${it N,N,N}$-trimethylglycine group (AMP03). AMP03 was found to exhibit relatively high adsorption ability for Rh(III) for [HNO$$_{3}$$]$$_{rm surp}$$ $$<$$ 0.02 M ([HNO$$_{3}$$]$$_{rm surp}$$ denotes HNO$$_{3}$$ concentration in the supernatant), and the ${it K$_{d}$}$ values increase significantly with the addition of triethylamine or tris(2-aminoethyl)amine to 0.12 M HNO$$_{3}$$ solutions. In contrast, the addition of thiourea leads to a decrease in the ${it K$_{d}$}$ values; i.e., a masking effect on Rh(III) was observed. These results show that AMP03 has a significant potential for effectively recovering Rh from HNO$$_{3}$$ solution.

Journal Articles

Complexing agents for oxonium anions of Mo and Re and their masking effects on extraction using N-donor extractants

Sasaki, Yuji; Suzuki, Tomoya; Morita, Keisuke; Tsubata, Yasuhiro

Chemistry Letters, 43(10), p.1538 - 1539, 2014/10

 Times Cited Count:3 Percentile:82.99(Chemistry, Multidisciplinary)

Several complexing agents including soft donor in their structures are examined for the masking effects of Mo and Re through solvent extraction. The available extractants are hexaoctyl-nitrilotriacetamide (NTAamide) and methyliminodioctylacetamide (MIDOA), whose extractants have high D(Mo, Re). It is clear that Mo and Re in HNO$$_{3}$$ dissolving N-donor ligands, ethylenediamine, diethylenetriamine, and 1,3-diaminopropane, can be suppressed for extraction into organic phase. The ligands including sulfur donor, e.g., thiourea, are also tested, however, less masking effect can be seen.

Journal Articles

Uranyl species in 1-Ethyl-3-methylimidazolium nitrate ([EMI][NO$$_{3}$$]) solution of [EMI]$$_{2}$$[UO$$_{2}$$(NO$$_{3}$$)$$_{4}$$]; First spectrophotometric evidence for existence of [UO$$_{2}$$(NO$$_{3}$$)$$_{4}$$]$$^{2-}$$

Sasaki, kotoe*; Suzuki, Tomoya*; Arai, Tsuyoshi*; Takao, Koichiro*; Suzuki, Shinichi; Yaita, Tsuyoshi; Ikeda, Yasuhisa*

Chemistry Letters, 43(5), p.670 - 672, 2014/05

 Times Cited Count:5 Percentile:74.63(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Adsorption behavior of lanthanide ions on nonbiological phospholipid membranes; A Model study using liposome

Yamasaki, Shinya; Shirai, Osamu*; Kano, Kenji*; Kozai, Naofumi; Sakamoto, Fuminori; Onuki, Toshihiko

Chemistry Letters, 42(8), p.819 - 821, 2013/08

 Times Cited Count:2 Percentile:84.96(Chemistry, Multidisciplinary)

The adsorption behavior of lanthanide ions (except for Pm) on liposomes composed of phosphatidylcholine and cholesterol was examined to understand the interaction between lanthanide ions and the phosphoryl moiety of phospholipids. The adsorption of lanthanide ions increased with an increase in pH under the weakly acidic conditions. Selective adsorption with the local maximum at the Er$$^{3+}$$ ion and local minimum at the Er$$^{3+}$$ ion was observed, similar to the selective adsorption of the bacterial cell surface but different from that of orthophosphates. These results indicate that the adsorption of lanthanide on the phospholipid does not result from simple adsorption on orthophosphate functional groups but by the composition and molecular structure of the phospholipid. Our results strongly suggest that liposomes can be used as a simple biomembrane model without any biological activity for the study of adsorption of lanthanide ions.

Journal Articles

Redox behavior of uranium(VI) adsorbed onto a phosphate-modified indium tin oxide electrode

Suzuki, Yoshinori*; Nankawa, Takuya; Onuki, Toshihiko

Chemistry Letters, 42(8), p.888 - 890, 2013/08

 Times Cited Count:0 Percentile:100(Chemistry, Multidisciplinary)

no abstracts in English

Journal Articles

Novel soft-hard donor ligand, NTAamide, for mutual separation of trivalent actinides and lanthanides

Sasaki, Yuji; Tsubata, Yasuhiro; Kitatsuji, Yoshihiro; Morita, Yasuji

Chemistry Letters, 42(1), p.91 - 92, 2013/01

 Times Cited Count:21 Percentile:36.73(Chemistry, Multidisciplinary)

The new N-donor extractant, NTAamide, is synthesized and tested for extraction and separation of Am-Cm-Ln. It was found that the high separation factors for An-Ln can be seen at 0.1-0.2M HNO$$_{3}$$, which suggest the de-protonation to N donor is important to show the high SF between An and Ln. From the present work, the stable N-donor extractant having high SF of An-Ln from nitric acid to n-dodecane can be obtained. The highest separation factor, 6.5, of Am-Cm for the condition of 0.5M NTAamide (C8) in n-dodecane and 10 mM TEDGA in 0.2M HNO$$_{3}$$ as one of the highest SF values is found. NTAamide is the promising extractants for partitioning process of Am-Cm-Ln.

Journal Articles

Intrinsic edge asymmetry in narrow zigzag hexagonal heteroatomic nanoribbons causes their subtle uniform curvature

Avramov, P.; Fedorov, D. G.*; Sorokin, P. B.*; Sakai, Seiji; Entani, Shiro; Otomo, Manabu; Matsumoto, Yoshihiro; Naramoto, Hiroshi*

Journal of Physical Chemistry Letters (Internet), 3(15), p.2003 - 2008, 2012/08

 Times Cited Count:29 Percentile:19.98(Chemistry, Physical)

Journal Articles

Isotope ratio analysis of individual plutonium and uranium-plutonium mixed oxide particles by thermal ionization mass spectrometry with a continuous heating method

Suzuki, Daisuke; Kokubu, Yoko; Lee, C. G.; Esaka, Fumitaka; Magara, Masaaki; Kimura, Takaumi

Chemistry Letters, 41(1), p.90 - 91, 2012/01

 Times Cited Count:6 Percentile:69.88(Chemistry, Multidisciplinary)

In conventional isotope ratio analysis of individual plutonium particles, the analytical procedure is complicated, because the particles have to be dissolved prior to the measurement. The chemical treatments may cause contamination of $$^{238}$$U existing in the environment. This makes it difficult to obtain accurate $$^{238}$$Pu/$$^{239}$$Pu isotope ratio. In the present work, an analytical method by a combination of single particle transfer and thermal ionization mass spectrometry with a continuous heating method is examined for individual plutonium particles, namely the particles are measured without any chemical treatments. In addition, the technique is applied to the analysis of individual uranium-plutonium mixed oxide (MOX) particles. The results of analysis of individual particles produced from standard solutions indicate that all isotope ratios are consistent with the certified values. There is no effect of isobaric interference on the results. In conclusion, the proposed analytical method is a useful tool for the isotope ratio analysis of plutonium and MOX particles without any chemical treatments.

Journal Articles

Interactions of the rare earth elements-desferrioxamine B complexes with ${it Pseudomonas fluorescens}$ and $$gamma$$-Al$$_{2}$$O$$_{3}$$

Onuki, Toshihiko; Yoshida, Takahiro*

Chemistry Letters, 41(1), p.98 - 100, 2012/01

 Times Cited Count:8 Percentile:63.85(Chemistry, Multidisciplinary)

We have studied the interactions of REEs (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er) - desferrioxamine B (DFO) complexes with ${it Pseudomonas fluorescens}$ cells and with $$gamma$$-Al$$_{2}$$O$$_{3}$$, at pH 4 - 9. The higher percent adsorption of REEs was obtained at lower pHs on P. Fluorescens cells and at higher pHs on $$gamma$$-Al$$_{2}$$O$$_{3}$$. Degree of negative anomaly of Ce compared to its neighboring REEs, La(III) and Pr(III) decreased with increasing pH. Thus, the pH dependence of Ce anomaly is predominantly dependent on the stability of Ce(IV)-DFO complex.

Journal Articles

Specific sorption behavior of actinoids on biogenic Mn oxide

Tanaka, Kazuya*; Tani, Yukinori*; Onuki, Toshihiko

Chemistry Letters, 40(8), p.806 - 807, 2011/08

 Times Cited Count:7 Percentile:65.98(Chemistry, Multidisciplinary)

We made sorption experiments of actinides on Mn oxide in dilute NaCl solution. Sorption affinity of actinides on synthetic Mn oxide was Th(IV) $$>$$ U(VI) $$>$$ Np(V). The specific sorption behavior of actinides on biogenic Mn oxide was observed. Thorium sorbed on biogenic Mn oxide was desorbed into solution with increasing time. Neptunium was not sorbed on biogenic Mn oxide. The specific sorption behavior is possibly due to organic ligands released from microorganisms and surface property of biogenic Mn oxide.

Journal Articles

Formation constants of Eu(III)-carboxylates determined by ion-selective liquid membrane electrode

Sasaki, Takayuki*; Yoshida, Hatsumi*; Kitatsuji, Yoshihiro; Takagi, Ikuji*; Moriyama, Hirotake*

Chemistry Letters, 40(8), p.870 - 871, 2011/08

 Times Cited Count:0 Percentile:100(Chemistry, Multidisciplinary)

Trivalent metal ion selective electrode (ISE) consisting of bis-(diphenylphosphoryl)-methane as an ionophore was developed for the determination of formation constants with organic ligands. The ISE prepared exhibited Nernstian response to the concentration of Eu$$^{3+}$$ in the test solutions. Even in the presence of carboxylic acids such as malonic acid in samples, the obtained potential values were found to be stable and reproducible during the measurement time. The present formation constants of Eu with carboxylates were in good agreement with the reported values.

Journal Articles

Fabrication of silica nanomaterials reflecting morphological transition of DNA mediated by a silane-appended ionic liquid

Shimojo, Kojiro; Mitamura, Hisayoshi; Mouri, Tsuyoshi; Naganawa, Hirochika

Chemistry Letters, 40(5), p.435 - 437, 2011/05

 Times Cited Count:3 Percentile:80.91(Chemistry, Multidisciplinary)

A simple fabrication strategy of DNA-transcribed silica materials has been developed. An ionic liquid incorporating an alkoxysilane group is capable of binding with DNA and acts as nuclei for subsequent sol-gel reaction with tetramethoxysilane. Unique silica materials with worm-like, rod-shaped, toroidal, or linearly fibrous structures are created from the same DNA template through the morphological transition of DNA induced by the ionic liquid.

Journal Articles

Mutual separation of actinides from middle lanthanides by the combination of two neutral donors, $$N,N,N,N$$-tetraoctyl-3,6-dioxaoctanediamide and $$N,N,N,N$$-tetraetyldiglycolamide

Sasaki, Yuji; Morita, Yasuji; Kitatsuji, Yoshihiro; Kimura, Takaumi

Chemistry Letters, 39(8), p.898 - 899, 2010/08

 Times Cited Count:18 Percentile:45.26(Chemistry, Multidisciplinary)

The separation of Am and Cm from Sm, Eu and Gd was examined by using the combination of new extractant, DOODA (tetraoctyl-3,6-dioxaoctanediamide) and the masking agent, TEDGA (tetraethyl-diglycolamide). These reagents show the neutral donor feature and work in the acidic condition. DOODA can extract light lanthanides with high $$D$$ values into the organic phase, on the other hand TEDGA shows strong complexing ability with middle and heavy lanthanides in the aqueous phase. Americium and Cm behave as light lanthanides in this extraction system, therefore Am and Cm show high separation from middle lanthanides. The separation factors for $$D$$(Am)/$$D$$(Sm), $$D$$(Am)/$$D$$(Eu), and $$D$$(Am)/$$D$$(Gd) are 14.4, 40, and 111, respectively, under the condition of 0.3M DOODA/dodecane and 10 mM TEDGA/ 5M HNO$$_{3}$$. The high separation of Am and Cm from these lanthanides, having high neutron cross section, is confirmed in HNO$$_{3}$$-dodecane system without any pH buffer and metal salts.

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