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Unconjugated methoxylated catecholamine metabolites in human saliva. Quantitation methodology and comparison with plasma levels 总被引:1,自引:0,他引:1
A newly developed method for the simultaneous extraction and quantitation of the unconjugated levels of the catecholamine metabolites vanilmandelic acid (VMA), 3-methoxy-4-hydroxyphenylethylene glycol (MHPG) and homovanillic acid (HVA) in plasma by high performance liquid chromatography with electrochemical detection was modified and applied to studies of human saliva. The assay had a mean coefficient of variation under 3% for each of the metabolites. Levels of plasma VMA, MHPG and HVA were measured in 28 normal subjects and compared to their saliva levels, obtained before and after stimulation by mastication. Significant correlations were found between plasma and saliva MHPG and HVA, but there was no correlation between plasma and saliva VMA. Salivary MHPG and HVA can be reproducibly assayed and may be useful tools for indications of changes in central and peripheral catecholamine metabolism. 相似文献
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The technical lemma underlying the 5-dimensional topologicals-cobordism conjecture and the 4-dimensional topological surgery conjecture is a purely smooth category statement about locating 1-null immersions of disks. These conjectures are theorems precisely for those fundamental groups (good groups) where the 1-null disk lemma (NDL) holds. We expand the class of known good groups to all groups of subexponential growth and those that can be formed from these by a finite number of application of two operations: (1) extension and (2) direct limit. The finitely generated groups in this class are amenable and no amenable group is known to lie outside this class.Oblatum 20-II-1995 & 26-V-1995The first author is supported by the IHES, the Guggenheim foundation and the NSF.The second author is supported by the IHES and the Humboldt foundation. 相似文献
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Walfred S. Saari Wasyl Halczenko Mark B. Freedman Byron H. Arison 《Journal of heterocyclic chemistry》1982,19(4):837-840
Reaction of phenyl N-(8-quinolinyl)carbamate with sodium borohydride afforded 1,2-dihydro-4H-imidazo-[5,4,1-ij]quinolin-2-one, 2a . The 5,6-double bond of 2a was functionalized by reaction with nitrosyl chloride to give the nitroolefin 4 and by reaction with hypobromous acid to give the trans-bromohydrin 5 . Reaction of 5 with sodium azide led to the rearranged trans-6-azido-5-ol 7 , the structure of which was determined by 1H nmr studies. 相似文献
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In the 1B2u-1Ag system of naphthalene in a supersonic jet, rotational contour calculations show rotational temperatures of 2–60 K for argon carrier gas pressures of 1520-120 Torr. The b1u vibration v24 shows a high vibrational temperature which corresponds to the seeding temperature for pressures <400 Torr. 相似文献
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The photoionization detector (PID) is being developed for the detection of low centrations of oil in the carbon dioxide coolant of gas-cooled reactors. In this paper the theoretical response of the PID is derived and compared with its practical response and with that of the flame ionization detector (FID). The PID response is shown to depend primarily upon ionization potential and molar concentration unlike FID response which depends upon carbon number. The dependence of PID response upon the carrier gas used is discussed and the citerion of detection using the PID to measure oil vapour in carbon dioxide was found to be 2ppb. 相似文献
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M. A. Freedman 《Israel Journal of Mathematics》1983,46(1-2):145-160
Let {[I?λA(t)]?1:0≦λ≦Λ, 0≦t≦T} be a family of resolvents of bounded linear m-dissipative operatorsA(t) on a Banach spaceX. Suppose that the map(λ,t,x←[I?λA(t)]?1 x is jointly continuous. Then we show it is not necessarily true that for eachx∈X: (1) the product integral lim n → ∞ Π i=1 n [I - (t/n)A(it/n)]?1 x exists, (2) the initial value problemy′(t)=A(t)y(t), y(0)=x has a strong solution. 相似文献