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排序方式: 共有317条查询结果,搜索用时 15 毫秒
31.
Heikkinen JJ Kivimäki L Määttä JA Mäkelä I Hakalahti L Takkinen K Kulomaa MS Hytönen VP Hormi OE 《Colloids and surfaces. B, Biointerfaces》2011,87(2):409-414
A bio-ink for covalent deposition of thermostable, high affinity biotin-binding chimeric avidin onto sol-gel substrates was developed. The bio-ink was prepared from heterobifunctional crosslinker 6-maleimidohexanoic acid N-hydroxysuccinimide which was first reacted either with 3-aminopropyltriethoxysilane or 3-aminopropyldimethylethoxysilane to form silane linkers 6-maleimide-N-(3-(triethoxysilyl)propyl)hexanamide or -(ethoxydimethylsilyl)propyl)-hexanamide. C-terminal cysteine genetically engineered to chimeric avidin was reacted with the maleimide group of silane linker in methanol/PBS solution to form a suspension, which was printed on sol-gel modified PMMA film. Different concentrations of chimeric avidin and ratios between silane linkers were tested to find the best properties for the bio-ink to enable gravure or inkjet printing. Bio-ink prepared from 3-aminopropyltriethoxysilane was found to provide the highest amount of active immobilized chimeric avidin. The developed bio-ink was shown to be valuable for automated fabrication of avidin-functionalized polymer films. 相似文献
32.
We have developed a methodology for generating milligram amounts of functional Eph tyrosine kinase receptor using the protein engineering approach of expressed protein ligation. Stimulation with ligand induces efficient autophosphorylation of the semisynthetic Eph construct. The in vitro phosphorylation of key Eph tyrosine residues upon ligand-induced activation was monitored via time-resolved, quantitative phosphoproteomics, suggesting a precise and unique order of phosphorylation of the Eph tyrosines in the kinase activation process. To our knowledge, this work represents the first reported semisynthesis of a receptor tyrosine kinase and provides a potentially general method for producing single-pass membrane proteins for structural and biochemical characterization. 相似文献
33.
We prove an equivalence result between the validity of a pointwise Hardy inequality in a domain and uniform capacity density
of the complement. This result is new even in Euclidean spaces, but our methods apply in general metric spaces as well. We
also present a new transparent proof for the fact that uniform capacity density implies the classical integral version of
the Hardy inequality in the setting of metric spaces. In addition, we consider the relations between the above concepts and
certain Hausdorff content conditions. 相似文献
34.
We give a sufficient condition for a metric (homology) manifold to be locally bi-Lipschitz equivalent to an open subset in
R
n
. The condition is a Sobolev condition for a measurable coframe of flat 1-forms. In combination with an earlier work of D.
Sullivan, our methods also yield an analytic characterization for smoothability of a Lipschitz manifold in terms of a Sobolev
regularity for frames in a cotangent structure. In the proofs, we exploit the duality between flat chains and flat forms,
and recently established differential analysis on metric measure spaces. When specialized to R
n
, our result gives a kind of asymptotic and Lipschitz version of the measurable Riemann mapping theorem as suggested by Sullivan. 相似文献
35.
In applications of signal processing and pattern recognition, eigenvectors and eigenvalues of the statistical mean of a random matrix sequence are needed. Iterative methods are suggested and analyzed, in which no sample moments are used. Convergence is shown by stochastic approximation theory. 相似文献
36.
37.
Juha Javanainen 《Optics Communications》1984,50(1):26-30
We study theoretically free-induction decay (FID) in an inhomogeneously broadened system of two-level atoms whose transition frequencies fluctuate according to the Ornstein-Uhlenbeck process. A numerical solution of the model shows that at low intensities the saturation behaviour of FID may depend strongly on the statistics of the fluctuations, but at high intensities the fluctuations play a minor role. The results mimic qualitatively the recent experimental data of DeVoe and Brewer, but a full quantitative agrrement with experiments is not reached. 相似文献
38.
Preparation of macroscopic amount of C60 clusters (fullerenes) by the iodine laser is reported. 相似文献
39.
Juha Knuutinen Reino Laatikainen Jaakko Paasivirta 《Magnetic resonance in chemistry : MRC》1980,14(5):360-365
The 13C NMR spectra of six hydroxybenzenes, all chlorobenzenes, all chlorophenols and eight chlorocatechols are measured and assigned. The additivity of the substituent effects and the usefulness of some corrective parameters are studied with regression analysis. The order of the chemical shifts is most efficiently predicted by the simplest substituent effect model, containing only the direct effects of the substituents, although the 95% confidence limits of the calculated shifts are as high as 5.6 ppm. If the chemical shifts need to be predicted within the measuring errors (approximately 0.05–0.10 ppm, in the present data), the number of necessary corrections is very impractical. The correction parameters are found to be independent of the solvent if no conformational effects are operative. These corrections, or the non-additivity parameters, are thus theoretically interesting. Approximate 1J(CH) couplings are also reported and the additivity of substitution effects on these parameters are discussed. 相似文献
40.
Juha?M.?Saarela Torbj?rn?L?fqvist Kerstin?Ramser Per?Gren Erik?Olson Jan?Niemi Mikael?Sj?dahl 《Central European Journal of Physics》2010,8(2):235-241
This study is focused on exploring the feasibility of an all-optic surface scanning method in determining the size and position
of a submerged, laser generated, optoacoustic (OA) source. The optoacoustic effect in this case was generated when the absorption
of a short electromagnetic pulse in matter caused a dielectric breakdown, a plasma emission flash and a subsequent acoustic
wave. In the experiment, a laser pulse with λ = 1064 nm and 12 ns pulse length was aimed at a volume of deionized water. When
the laser beam was focused by a f = 16 mm lens, a single dielectric breakdown spot occurred. When a f = 40 mm was used several breakdowns in a row were induced. The breakdowns were photographed using a double shutter camera.
The acoustic wave generated by the dielectric breakdowns were detected at a point on the water surface using a laser Doppler
vibrometer (LDV). First, the LDV signal was used to calculate the speed of sound with an accuracy of 10 m/s. Secondly, the
location and length of the dielectric breakdown was calculated with an accuracy of 1 mm. The calculated position matched the
breakdown location recorded by a camera. The results show that it is possible to use LDV surface measurements from a single
spot to determine both the position and length of the OA source as well as the speed of sound in the medium. Furthermore,
the LDV measurements also show a secondary peak that originates from the OA source. To unravel the origin and properties of
this interesting feature, further investigations are necessary 相似文献