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61.
John L. Oscarson Peiming Wang Sue E. Gillespie Reed M. Izatt Gerald D. Watt Charles D. Larsen Juan A. R. Renuncio 《Journal of solution chemistry》1995,24(2):171-200
The interaction of adenosine 5-monophosphate (AMP), adenosine 5-diphosphate (ADP), and adenosine 5-triphosphate (ATP) ions with protons in aqueous solution has been studied calorimetrically from 50 to 125°C and 1.52 MPa. At each temperature, the reaction of acidic AMP with tetramethylammonium hydroxide was combined with the heat of ionization for water to obtain the enthalpy of protonation of AMP, while the reactions of HCl with deprotonated tetramethylammonium salts of ADP and ATP were used to obtain the enthalpies of protonation of ADP and ATP. Equilibrium constant K, enthalpy change Ho, entropy change So, and heat capacity change C
p
o
values were calculated for the stepwise protonation reactions as a function of temperature. The reactions involving the first protonation of AMP, ADP, and ATP and the third protonation of ADP and ATP were endothermic over the temperature range studied, while that involving the second protonation is exothermic for AMP and ADP, but is exothermic below 100°C and endothermic at 125°C in the case of ATP. Consequently, log K values for the first and third protonation reactions (phosphate groups) increase while those for the second protonation reaction (N1-adenine) decrease in the cases of AMP and ADP and go through a minimum in the case of ATP as temperature increases. The Ho values for all protonation reactions increase with temperature. The magnitude and the trend for the Ho, So, and C
p
o
values with temperature are discussed in terms of solvent-solute interactions. The magnitude of the C
p
o
values for the second protonation is consistent with little interaction between the phosphate ion and the protonated N1 site of the adenine moiety in AMP, but indicates moderate interaction between these groups in ADP, and strong interaction in ATP. 相似文献
62.
63.
建立了一种新的基于碰撞诱导解离(CID)碎裂模式鉴定精氨酸-腺苷二磷酸(ADP)-核糖基化多肽的新方法. 首先,在碱性条件下将精氨酸-ADP-核糖基化血管紧张素-Ⅰ转变为鸟氨酸化血管紧张素-Ⅰ,或在磷酸二酯酶和碱性磷酸酶处理下水解为精氨酸核糖基化血管紧张素-Ⅰ,然后对上述2种衍生物进行基于CID碎裂模式的串联质谱分析. 结果表明,与未衍生的精氨酸-ADP-核糖基化血管紧张素-Ⅰ相比,在鸟氨酸化血管紧张素-Ⅰ和精氨酸核糖基化血管紧张素-Ⅰ的质谱图上发现大部分来自于肽骨架碎裂的离子峰,可提供足够的序列信息以确定精氨酸-ADP-核糖基化位点. 相似文献
64.
Based on a specially designed optical structure, an efficient cascaded third-harmonic-generation(THG) output of a 1064-nm, pico-seconds pulse laser is successively realized by using an NH_4H_2PO_4(ADP) crystal that acts as the secondharmonic-generation component and sum-frequency-generation component. The maximum THG output is 1.61 mJ, and the highest conversion efficiency from 1064 nm to 355 nm reaches 35%, which are obviously superior to the results obtained using a KDP crystal under the same circumstance. The further phase-matching analysis indicates that this THG configuration of ADP crystal can be applied to various fundamental wavelengths in a range of 1 μm–1.1 μm. Compared with the previously reported KDP THG converter, which is based on a similar principle, the present ADP THG converter is favorable for large-energy, high-efficiency operation because of the larger effective nonlinear optical coefficient deffand higher laser damage threshold. 相似文献
65.
Synthesis of silylene–propenylene oligomers via catalytic polycondensation of diallyldiorganosilanes
Bogdan Marciniec Mariusz Lewandowski Ewa Kwiatkowska 《Journal of polymer science. Part A, Polymer chemistry》1997,35(15):3299-3304
Acyclic diene polycondensation (ADP) of diallyldiorganosilanes (CH2CHCH2)2SiR2 (where R = Me, Ph), in the presence of various ruthenium and rhodium complexes, led predominantly to linear silylene–propenylene oligomers. Ruthenium catalysts (e.g. RuCl2(PPh3)3, RuHCl(CO)(PPh3)3, and RuCl(SiMe3)(CO)(PPh3)2) were found to be more efficient than the rhodium ones. The reaction proceeds via preliminary catalytic isomerization of allylsilane to silyl-1-propenes followed by their oligococondensation. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3299–3304, 1997 相似文献
66.
《Radiation measurements》2001,34(1-6):325-329
Detailed calibration studies of selected types of SSNTDs have been performed at the SINS using monoenergetic light ions of energy within MeV range. These studies were motivated by the application of such detectors in the optimal way for plasma physics experiments. This paper shows track diameter evolutions versus particle energy and etching time. Some conclusions related to track registration phenomenon and detection properties of the investigated detectors, especially of the PM-355 type are also presented. 相似文献
67.
This paper presents the results of the influence of soft X-ray radiation on craters induced in SSNTDs by energetic α particles and protons of energy in the MeV range. We checked two detectors of the PM-355 and CR-39 types in order to verify and compare their resistance to the harsh conditions of high-temperature plasma experiments. To determine this effect some detector samples were first irradiated with α particles emitted from natural α particle sources and protons delivered by a particle accelerator. After that these samples were exposed to soft X ray radiation emitted from an X ray tube and also from the PF-1000 Plasma Focus facility. Doses during X ray irradiations varied from 0 up to tens of kGy. The irradiated samples were then etched in steps and track diameters were determined versus the absorbed dose and etching time and compared with those measured in samples not exposed to X ray radiation. 相似文献
68.
69.
Hans A. V. Kistemaker Lucien N. Lameijer Nico J. Meeuwenoord Prof. Dr. Herman S. Overkleeft Prof. Dr. Gijsbert A. van der Marel Dr. Dmitri V. Filippov 《Angewandte Chemie (International ed. in English)》2015,54(16):4915-4918
The post‐translational modification of proteins that is known as adenosine diphosphate ribosylation (ADPr) regulates a wide variety of important biological processes, such as DNA‐damage repair and cellular metabolism. This modification is also involved in carcinogenesis and the process of aging. Therefore, a better understanding of the function of ADP‐ribosylation is crucial for the development of novel therapeutics. To facilitate the elucidation of the biology of ADPr, the availability of well‐defined fragments of poly(ADP‐ribose) is essential. Herein we report a solid‐phase synthetic approach for the preparation of ADP‐ribose oligomers of exactly defined length. The methodology is exemplified by the first reported synthesis of an ADP‐ribose dimer and trimer. 相似文献
70.
A. Szydlowski A. Banaszak M.J. Sadowski M. Scholz J. Wolowski 《Radiation measurements》2005,40(2-6):479-482
This paper reports on measurements performed with the use of SSNTDs at the PF-1000 Plasma-Focus facility in Warsaw and TEXTOR tokamak in Juelich. Fusion reaction protons were measured within the PF-1000 facility and TEXTOR tokamak. 相似文献