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11.
微囊藻毒素-LR的特征红外光谱 总被引:1,自引:0,他引:1
利用傅里叶变换红外(FTIR)光谱仪研究了微囊藻毒素-LR在扫描范围4 000~600 cm-1的红外吸收光谱图,微囊藻毒素-LR分子构成中的主要官能团,如带有单一取代基的苯环、胍基、γ-羧基等特征红外吸收带在谱图上均得到了确认。 相似文献
12.
Roh JH Tyagi M Briber RM Woodson SA Sokolov AP 《Journal of the American Chemical Society》2011,133(41):16406-16409
The dynamics of RNA contributes to its biological functions such as ligand recognition and catalysis. Using quasielastic neutron scattering spectroscopy, we show that Mg(2+) greatly increases the picosecond to nanosecond dynamics of hydrated tRNA while stabilizing its folded structure. Analyses of the atomic mean-squared displacement, relaxation time, persistence length, and fraction of mobile atoms showed that unfolded tRNA is more rigid than folded tRNA. This same result was found for a sulfonated polystyrene, indicating that the increased dynamics in Mg(2+) arises from improved charge screening of the polyelectrolyte rather than specific interactions with the folded tRNA. These results are opposite to the relationship between structural compactness and internal dynamics for proteins in which the folded state is more rigid than the denatured state. We conclude that RNA dynamics are strongly influenced by the electrostatic environment, in addition to the motions of local waters. 相似文献
13.
Judith M. Wingate Bari Hoffman Ruddy Donna S. Lundy Jeffrey Lehman Roy Casiano Savita P. Collins Gayle E. Woodson Christine Sapienza 《Journal of voice》2005,19(1):124-131
Adductor spasmodic dysphonia (ADSD) adversely affects a speaker's ability to effectively communicate. For many individuals suffering with ADSD, botulinum toxin (Botox) is the chosen treatment to remediate the symptoms. Although Botox's effects on symptom remediation have been examined before, patient perception of improvement post-Botox has been examined less frequently. Further, no studies have addressed the symptomatic changes in older adults that occur after Botox treatment. The Voice Handicap Index (VHI) was used as the instrument to assess older patient's (>65 years) perception of how ADSD impacts certain areas of their life pre- and post-Botox injection. The outcome of the VHI was related to a clinical judgment of voice severity. Participants also completed the Social Readjustment Rating Scale (SRRS) to examine overall stress level, and the outcome of the SRRS was correlated to postinjection VHI scores. Results indicated no significant correlation between VHI scores and voice severity or SRRS ratings. The current study suggests further study of voice outcomes with older adults with ADSD is needed. 相似文献
14.
Tetsuo Nakatsu D. John Faulkner Gayle K. Matsumoto Jon Clardy 《Tetrahedron letters》1984,25(9):935-938
The structure of purino-diterpene 2, derived from an unknown antimicrobial metabolise of Agelas mauritiana, was determined by X-ray analysis. 相似文献
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Treatment of N-alkyl derivatives of 3,6-dichlorophthalimide and 4,5-dichlorophthalimide with potassium nitrite gave 3-hydroxy-6-nitro- and 4-hydroxy-5-nitrophthalimides. The potassium salts of these phenols were alkylated by dialkyl sulfates. The products were reduced to the 3-amino-6-alkoxy- and 4-amino-5-alkoxyphthalimides, and the fluorescence emission spectra of these products were measured. Hydrazinolysis of the phthalimides in a toluene medium gave phthalhydrazides. The luminescence spectra of several aminophthalhydrazides were measured. The infrared and proton magnetic resonance spectra of these and of some nitrophthalhydrazides were measured and aspects of these spectra characteristic of phthalhydrazides were identified. 相似文献
17.
Jon Clardy Greg Van Duyne Ana Gallardo Eduardo Manta Julio D. Martín Cirilo Prez Ricardo Prez Jos L. Ravelo Matías L. Rodríguezb Gayle K. Schulte 《Tetrahedron letters》1987,28(52):6699-6700
A new diterpene, β-dictalediol monoacetate (
), has been isolated from a brown alga
X-ray crystal structure studies of
have revealed the existence of two polymorphic modifications: dimorph
in a chair/boat/chair conformation, and dimorph
in a chair/chair/chair conformation. 相似文献
18.
From the soft coral Antheliaedmondsoni two new diterpenoids, waixenicin-A (1) and -B (2) have been Isolated. Their structures were elucidated by1H and13C NMR analysis and the relative stereochemistry was determined by x-ray diffraction of crystalline waixenicin-B (2). 相似文献
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