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1.
Seppo Hassi Manfred Mö ller Henk de Snoo 《Proceedings of the American Mathematical Society》2006,134(10):2885-2893
The class of Nevanlinna functions consists of functions which are holomorphic off the real axis, which are symmetric with respect to the real axis, and whose imaginary part is nonnegative in the upper halfplane. The Kac subclass of Nevanlinna functions is defined by an integrability condition on the imaginary part. In this note a further subclass of these Kac functions is introduced. It involves an integrability condition on the modulus of the Nevanlinna functions (instead of the imaginary part). The characteristic properties of this class are investigated. The definition of the new class is motivated by the fact that the Titchmarsh-Weyl coefficients of various classes of Sturm-Liouville problems (under mild conditions on the coefficients) actually belong to this class.
2.
The effects of four wash procedures on the concentration of chromium in a pooled sample of human scalp hair are compared. The wash solutions examined are Triton X-100, sodium lauryl sulphate, acetone, and a mixture (1 + 1) of hexane and ethanol. The plateaux reached for hair chromium concentration are functions of the number of washings, and are characteristic for each wash solution. The wash procedure recommended involves two 20-min washes with aqueous 1% sodium lauryl sulphate solution after a hexane rinse. 相似文献
3.
Dr. Seppo Seikkala 《Monatshefte für Mathematik》1982,93(3):225-238
We shall derive existence, uniqueness and comparison results for the functional differential equationx(t)=f(t, x), a. e.tI, with classical Nicoletti boundary conditionsx
i(ti)=y
iX, iA, whereI is a real interval,A is a nonempty set andX is a Banach space. 相似文献
4.
Preparation of 4-Vinyl-2(5H)-Furanoid Structural Unit via Organosilicon and - Selenium Intermediates
Seppo I. Pennanen 《合成通讯》2013,43(10):865-871
Two syntheses of the 2(5H)-furanoid structural unit (especially the 3-methyl derivative 1) have been reported from this laboratory.1,2 The unit 1 is found in many naturally occurring compounds (especially sesqui terpenes). The 4-substi tuted d erivatives of 1 also occur frequently i n natural products, e.g. furospongolide3 2. 相似文献
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Z-configured 1,4-diene or β,γ-unsaturated carbonyl systems are readily available by the Wittig reaction. Isomerization required for access into the E-series can easily be accomplished by irradiation using an ordinary tungsten lamp and diphenyl disulphide sensitizer. There is very little formation of conjugated isomers (less than 1%). 相似文献
7.
Leo Syrjänen Martti Tolvanen Mika Hilvo Ayodeji Olatubosun Alessio Innocenti Andrea Scozzafava Jenni Leppiniemi Barbara Niederhauser Vesa P Hytönen Thomas A Gorr Seppo Parkkila Claudiu T Supuran 《BMC biochemistry》2010,11(1):1-13
Background
The β-carbonic anhydrase (CA, EC 4.2.1.1) enzymes have been reported in a variety of organisms, but their existence in animals has been unclear. The purpose of the present study was to perform extensive sequence analysis to show that the β-CAs are present in invertebrates and to clone and characterize a member of this enzyme family from a representative model organism of the animal kingdom, e.g., Drosophila melanogaster.Results
The novel β-CA gene, here named DmBCA, was identified from FlyBase, and its orthologs were searched and reconstructed from sequence databases, confirming the presence of β-CA sequences in 55 metazoan species. The corresponding recombinant enzyme was produced in Sf9 insect cells, purified, kinetically characterized, and its inhibition was investigated with a series of simple, inorganic anions. Holoenzyme molecular mass was defined by dynamic light scattering analysis and gel filtration, and the results suggested that the holoenzyme is a dimer. Double immunostaining confirmed predictions based on sequence analysis and localized DmBCA protein to mitochondria. The enzyme showed high CO2 hydratase activity, with a kcat of 9.5 × 105 s-1 and a kcat/KM of 1.1 × 108 M- 1s- 1. DmBCA was appreciably inhibited by the clinically-used sulfonamide acetazolamide, with an inhibition constant of 49 nM. It was moderately inhibited by halides, pseudohalides, hydrogen sulfide, bisulfite and sulfate (KI values of 0.67 - 1.36 mM) and more potently by sulfamide (KI of 0.15 mM). Bicarbonate, nitrate, nitrite and phenylarsonic/boronic acids were much weaker inhibitors (KIs of 26.9 - 43.7 mM).Conclusions
The Drosophila β-CA represents a highly active mitochondrial enzyme that is a potential model enzyme for anti-parasitic drug development. 相似文献8.
Operator realizations of matrix-valued Herglotz-Nevanlinna functions play an important and essential role in system theory, in the spectral theory of bounded nonselfadjoint operators, and in interpolation problems. Here, a generalization for realization results of the Brodskiǐ-Livsic type is given for Herglotz-Nevanlinna functions whose spectral measures are compactly supported. 相似文献
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