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851.
Jörgen Ekström Masataka Murakami Rosanna Inzitari Nina Khosravani Chiara Fanali Tiziana Cabras Junko Fujita‐Yoshigaki Hiorshi Sugiya Irene Messana Massimo Castagnola 《Journal of separation science》2009,32(17):2944-2952
Two peptides (MW 1211.7 and 928.5 Da) were detected by RP–HPLC–ESI–MS analysis of parotid saliva secreted upon continuous parasympathetic stimulation. The peptide with the higher mass (PSPFr‐A) corresponded to the N‐terminal dodecapeptide (Fragment 1–12) of rat parotid secretory protein (PSP), while the peptide with the lower mass (PSPFr‐B) corresponded to the 4–12 fragment of the same protein. During stimulation, the PSPFr‐A secretion increased, while the PSPFr‐B secretion decreased (HPLC–ESI–MS). In the presence of cycloheximide, PSPFr‐A was not demonstrated, while the PSPFr‐B secretion decreased. In the presence of aprotinin, the PSPFr‐B secretion was almost abolished, while the PSPFr‐A secretion increased to higher levels than those observed in the absence of the inhibitor. In vitro perfusion, with artificial solution, of stimulated rat parotid glands excluded that the fragments were derived from the circulation. Neither peptide occurred in enriched granule preparations from unstimulated glands. The results suggest that at least two pathways – granular and vesicular – are responsible for the generation of the two peptides. PSPFr‐A is the first cleavage product in both pathways. PRPFr‐B is probably generated from granular PSPFr‐A only and, at the end of the granule mediated pathway, by the action of an enzyme of the serine protease class. 相似文献
852.
Tatsuo Matsushima Anton Kokalj Hideo Orita Toshitaka Kubo Masataka Sakurai Takahiro Kondo Junji Nakamura 《Surface science》2012,606(13-14):1029-1036
A sharp change in the N2 emission channel from N2O(a) → N2(g) + O(a) to N(a) + N(a) → N2(g) has been found at around 500 K in a steady-state NO + D2 reaction over stepped Pd(211) = [(S)3(111) × (100)] by means of angle-resolved desorption. The desorbing N2 is highly collimated at around 30° off normal toward the step-down direction below about 500 K due to the intermediate N2O decomposition, whereas, above 500 K, the near normally directed desorption due to the recombination of N(a) is relatively enhanced. The N2O decomposition channel is promoted when the reaction is carried out with hydrogen (deuterium) and the channel change is accelerated by quick changes of the amounts of surface hydrogen and oxygen (or NO(a)) into the opposite directions, and enhanced nitrogen removal as ammonia on the resultant hydrogen-rich surface. In the steady-state NO + CO reaction, the N2 emission channel gradually changes above 500 K toward recombination. A model for the off-normal N2 emission is briefly described. 相似文献
853.
854.
Daiki Fukuhara Masataka Yamauchi Satoru G. Itoh Hisashi Okumura 《Journal of computational chemistry》2023,44(4):534-545
In the replica-permutation method, an advanced version of the replica-exchange method, all combinations of replicas and parameters are considered for parameter permutation, and a list of all the combinations is prepared. Here, we report that the temperature transition probability depends on how the list is created, especially in replica permutation with solute tempering (RPST). We found that the transition probabilities decrease at large replica indices when the combinations are sequentially assigned to the state labels as in the originally proposed list. To solve this problem, we propose to modify the list by randomly assigning the combinations to the state labels. We performed molecular dynamics simulations of amyloid-β(16–22) peptides using RPST with the “randomly assigned” list (RPST-RA) and RPST with the “sequentially assigned” list (RPST-SA). The results show the decreases in the transition probabilities in RPST-SA are eliminated, and the sampling efficiency is improved in RPST-RA. 相似文献
855.
The reactive pyrolysis-gas chromatography technique was applied to verify the branching and/or cross-linking structures in an industrially available polycarbonate (PC) sample and its thermally treated one through identification of specific pyrolysis products directly reflecting the related abnormal structures. On the pyrogram of the thermally treated sample, the peaks reflecting the abnormal structures such as branching and/or cross-linking were observed together with those reflecting main chain and end groups. Furthermore, the fact that some of those characteristic peaks were also observed on the pyrogram of the industrially available PC sample prepared by the melt method indicated that the branching and/or cross-linking reactions would occur to some extent in the PC synthesized by the melt method. 相似文献
856.
Prof. Ryo Ohtani Jianeng Xu Dr. Junichi Yanagisawa Yuudai Iwai Takumi Ehara Dr. Kiyoshi Miyata Prof. Ken Onda Dr. Jenny Pirillo Prof. Yuh Hijikata Tomoaki Hiraoka Prof. Shinya Hayami Dr. Benjamin Le Ouay Prof. Masaaki Ohba 《Angewandte Chemie (International ed. in English)》2023,62(32):e202306853
We synthesized a (1-propylpyridinium)2[ReN(CN)4]-type organic–inorganic hybrid exhibiting water-vapor-induced drastic structural changes of the [ReN(CN)4]2− assemblies. Specifically, upon exposure to water vapor, dehydrated nitrido-bridged chains were converted to hydrated cyanido-bridged tetranuclear clusters via rearrangements of large molecular building units in the crystals. These switchable assembly forms display substantially different photo-physical properties, although in both cases the emission is caused by a metal-centered d–d transition. The nitrido-bridged chain exhibited a near-infrared (749 nm) emission, which blue-shifted as the temperature increased, while a visible (561 nm) emission and its red shift was demonstrated by the cyanido-bridged cluster. 相似文献
857.
The direct coupling reaction of D -ribosyl fluoride with typical π-excessive aromatic heterocycles such as furan, thiophene, pyrrole, benzofuran, benzothiophene, and indole and their trimethylsilyl derivatives was performed in the presence of boron trifluoride to afford the corresponding C-nucleosides in moderate to good yields. 相似文献