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1.
The investigation of europium(III) sulphate hydrate and samarium(III) sulphate hydrate was performed by thermal analysis (TG-DTG) and simultaneous infrared evolved gas analysis-Fourier transformed infrared (EGA-FTIR) spectroscopy. The TG, DTG and DTA curves were recorded at the 25–1400 °C in the dynamic air atmosphere by TG/DTA analyser. The infrared evolved gas analysis was obtained on the FTIR spectrometer. Eu2(SO4)3·nH2O (n = 3.97) and Sm2(SO4)3·nH2O (n = 8.11) were analysed, the dehydration and decomposition steps were investigated and the water content was calculated. The formation of different oxysulphates was studied.
The trace rare earth elements in Eu and Sm sulphates were determined by ICP-MS. The concentration of trace Eu, Sm, La, Gd, Y and Ce ranged from 3.9 × 10−6 to 1.5 × 10−4% (m/m). 相似文献
2.
Harri M. Salo Tuula M. Aaltonen S. Eveliina Markkula E. Ilmari Jokinen 《Photochemistry and photobiology》1998,67(4):433-437
Roach ( Rutilus rutilus ) were irradiated with a single dose of ultraviolet B (UVB) radiation (0.4 J/cm2 ) in order to study the effects of UVB on the nonspecific immune defense mechanisms of fish. Neutrophils and macrophages were isolated from the head kidney of fish on days 1–14 postirradiation. Both random and directed migration of neutrophils, studied by migration under agarose assay, were suppressed on day 1 after UVB irradiation. The respiratory burst of phorbol 12-myristate 13-acetatestimulated neutrophils and macrophages was also suppressed at days 1 and 2 after UVB irradiation. The suppression of migration and respiratory burst were restored or the responses were even enhanced later, but on the other hand spontaneous cytotoxicity of neutrophils toward 51 chromium-labeled K562 target cells stayed suppressed throughout the 14 day follow-up. This study indicates that UVB radiation has the potential to suppress the functioning of phagocytes and to compromise the immune system of fish. 相似文献
3.
Relativistic symmetry orbitals are given for the double group D3h. For atomic orbitals at the symmetry center a general expression is presented. The atomic orbitals of the s, p½, and p3/2 variety outside the center are also considered. The representation matrices are given in explicit form. 相似文献
4.
A few 2-substituted 1-(1-ethoxyethyl)benzimidazoles have been prepared and the rate constants for their hydrolysis measured at various temperatures and oxonium ion concentrations. The formal kinetics followed and the effect of varying the 2-substitution on the hydrolysis rate suggest that the acid-catalyzed cleavage of these compounds involves a rapid initial protonation of the benzimidazole ring and a subsequent rate-limiting heterolysis of the protonated substrate to form a free nitrogen base and an ocarbenium ion derived from the ethoxyethyl group. The values obtained for the entropy of activation are consistent with the assumed unimolecular nature of the rate-limiting step. The effects of 2-substituents on the acidities of the protonated substrates and their heterolysis rates have been compared. The latter partial reaction has been suggested to be the subject of steric acceleration. 相似文献
5.
Veli-Matti Mukkala Pivi Liitti Ilkka Hemmil Harri Takalo Cristina Matachescu Jouko Kankare 《Helvetica chimica acta》1996,79(1):295-306
The synthesis of novel thiazole-containing complexing agents and their luminescence properties with EuIII and TbIII ions are reported. One of these terpyridine analogues was also tested as an EuIII labelling reagent, and its luminescence properties as an antibody conjugate were studied. 相似文献
6.
Stereoselective syntheses of novel 5,6-difunctionalized-2-azabicyclo[2.1.1]hexanes containing 5-anti-fluoro or hydroxyl in one methano bridge and a variety of syn- or anti-chloro, fluoro, hydroxy, methyl, or phenyl substituents in the other methano bridge have been effected. Rearrangements of iodides to alcohols were initiated using Selectfluor. Rearrangement of alcohols to fluorides was initiated using Deoxo-Fluor. Ring opening of 2-azabicyclo[2.2.0]hex-5-ene exo-epoxide with organocopper reagents is regioselective at C(5). 相似文献
7.
Harri Räisälä Dr. Tuomas Lönnberg 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(18):4751-4756
An 11-mer oligonucleotide incorporating a central (2-iodobenzoylamino)methyl residue has been synthesized and palladated by oxidative addition of Pd2(dba)3. UV melting profiles of the duplexes formed by the palladated oligonucleotide with its natural complements were biphasic and the higher melting temperatures (Tm) exhibited considerable hysteresis. CD spectra, in turn, resembled those of canonical B-type double helices. Two-step denaturation, with the “low-Tm” melting involving only canonical base pairs and the “high-Tm” melting involving also dissociation of a PdII-mediated base pair, appears the most likely explanation for the observed UV melting profiles. As the latter step in all cases takes place at a higher temperature than denaturation of natural duplexes of the same length, the putative PdII-mediated base pairs are stabilizing. 相似文献
8.
9.
Four metal‐ion‐binding nucleosides, viz. 2,6‐bis(1‐methylhydrazinyl)‐9‐(β‐D ‐ribofuranosyl)‐9H‐purine ( 2a ) and its N‐acetylated derivative, 2b , 2,4‐bis(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)‐5‐(β‐D ‐ribofuranosyl)pyrimidine ( 3 ), and 2,4‐bis(1‐methylhydrazinyl)‐5‐(β‐D ‐ribofuranosyl)pyrimidine ( 4 ) have been synthesized. The ability of these nucleosides and the previously prepared 2,6‐bis(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)‐9‐(β‐D ‐ribofuranosyl)‐9H‐purine to form Pd2+‐ and Hg2+‐mediated complexes with uridine has been studied by 1H‐NMR spectroscopy. To obtain additional support for the interpretation of the NMR data, comparative measurements on the ternary‐complex formation between pyridine‐2,6‐dicarboxamide ( 5 ), pyrimidine nucleosides, and K2PdCl4 were carried out. 相似文献
10.
Luigi Lain Prof. Dr. Harri Lönnberg Dr. Tuomas Lönnberg 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(37):12424-12434
A dinucleoside‐3′,5′‐phosphodiester model, 5′‐amino‐4′‐aminomethyl‐5′‐deoxyuridylyl‐3′,5′‐thymidine, incorporating two aminomethyl functions in the 4′‐position of the 3′‐linked nucleoside has been prepared and its hydrolytic reactions studied over a wide pH range. The amino functions were found to accelerate the cleavage and isomerization of the phosphodiester linkage in both protonated and neutral form. When present in protonated form, the cleavage of the 3′,5′‐phosphodiester linkage and its isomerization to a 2′,5′‐linkage are pH‐independent and 50–80 times as fast as the corresponding reactions of uridylyl‐3′,5′‐uridine (3′,5′‐UpU). The cleavage of the resulting 2′,5′‐isomer is also accelerated, albeit less than with the 3′,5′‐isomer, whereas isomerization back to the 3′,5′‐diester is not enhanced. When the amino groups are deprotonated, the cleavage reactions of both isomers are again pH‐independent and up to 1000‐fold faster than the pH‐independent cleavage of UpU. Interestingly, the 2′‐ to 3′‐isomerization is now much faster than its reverse reaction. The mechanisms of these reactions are discussed. The rate accelerations are largely accounted for by electrostatic and hydrogen‐bonding interactions of the protonated amino groups with the phosphorane intermediate. 相似文献