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21.
A simple integrated optical refractometric sensor based on hollow-core antiresonant reflecting optical waveguides is proposed. The sensor uses the antiresonant reflecting guidance mechanism and permits one to measure the refractive index of a liquid filling the core by simply monitoring the transmitted spectrum. The device has been made with standard silicon technology, and the experimental results confirm numerical simulations performed in one- and two-dimensional geometry. The sensor exhibits a linear response over a wide measurement range (1.3330-1.4450) and a resolution of 9 x 10(-4) and requires a small analyte volume. 相似文献
22.
Romeo AA Capobianco JA English AM 《Journal of the American Chemical Society》2003,125(47):14370-14378
The role of hemoglobin (Hb) in transmitting the vasodilatory property of NO throughout the vascular system is of much current interest. NO exchange between Hb and low-molecular-weight nitrosothiols such as S-nitrosoglutathione (GSNO) has been speculated and reported in vitro. Previously, we reported that NO delivery from GSNO to Cysbeta93 of human oxyHb is prevented in the presence of the Cu chelators, neocuproine, and DTPA.(1) In the present work, 5 mM solutions of commercial human Hb were found by ICP-MS to contain approximately 20 microM Cu and Zn, suggesting the presence of Cu,Zn-superoxide dismutase (CuZnSOD), which was confirmed by Western blotting. SOD activity measurements were consistent with the presence of approximately 20 microM CuZnSOD monomer in 5 mM Hb solutions, which is the physiological concentrations of these proteins in the red blood cell. Incubation of 3.75 mM oxyHb (15 mM heme; 7.5 mM Cysbeta93) with 3.75 or 7.5 mM GSNO gave rise to 50% or 100% S-nitrosation, respectively, of Cysbeta93 as monitored by FTIR nu(SH) absorption, whereas excess GSNO over Cysbeta93 converted oxyHb to metHb due to the reaction, oxyHb + NO<==>metHb + NO(3)(-). Removal of CuZnSOD by anion-exchange chromatography yielded an oxyHb sample that was unreactive toward GSNO, and replacement with bovine CuZnSOD restored reactivity. Addition of 1 microM GSNO (Cysbeta93/GSNO = 1) to solutions diluted 10(4)-fold from physiological concentrations of oxyHb and CuZnSOD resulted largely in metHb formation. Thus, this work reports the following key findings: CuZnSOD is an efficient catalyst of NO transfer between GSNO and Cysbeta93 of oxyHb; metHb is not detected in oxyHb/GSNO incubates containing close to the physiological concentration (5 mM) of Hb and CuZnSOD when the Cysbeta93/GSNO molar ratio is 0.5 to 1.0, but metHb is detected when the total Hb concentration is low micromolar. These results suggest that erythrocyte CuZnSOD may play a critical role in preserving the biological activity of NO by targeting it from GSNO to Cysbeta93 of oxyHb rather than to its oxyheme. 相似文献
23.
H. Jesser H. Mohler H. Benz P. Balavoine G. Bruhns M. Sahyun D. Schenk G. Romeo H. Schmalfuß H. Werner W. Plahl W. Diemair und G. Lix 《Fresenius' Journal of Analytical Chemistry》1935,100(5-6):225-229
Ohne Zusammenfassung 相似文献
24.
H. Schmalfuß H. Werner G. Curli T. P. Hilditch H. E. Longenecker Fr. Kiermeier Fr. X. Maier C. I. Kruisheer P. C. den Herder G. Roeder B. Segal A. Romeo V. Crupi G. Dorta G. Lunde H. Kringstad E. Mathiesen A. Olsen F. N. Woodward S. R. Hoover S. Schmidt-Nielsen und J. Stone 《Fresenius' Journal of Analytical Chemistry》1941,121(1-2):55-59
Ohne Zusammenfassung 相似文献
25.
26.
The main topic consists of enhancing the geometrical and positioning accuracy of the machine tools with numerical control.
Currently, in order to minimize the errors met during the vertical motions of the moving elements in the structure of a machine
tool, various systems are used that are relatively complex and whose adjustments are difficult to do. This work is presenting
a balancing–compensation system of the elements moving vertically that includes three invention patents; it has a simple structure
that is easily adaptable to various types of machine tools. The newness element of the balancing-compensation system is represented
by the pressure regulator being used, whose operation principle and design is described into detail. The related results have
been reified in increasing by approximately 10 times the geometrical accuracy and, by default, the positioning accuracy of
the element moving in a vertical plane. 相似文献
27.
F. Romeo 《Journal of sound and vibration》2003,268(3):601-615
The problem of minimizing transmitted vibrations through finitely long periodic structures is addressed. Bi-coupled periodic element properties and arrangement are tailored to localize the response around the excitation source within any assigned frequency range. Bi-dimensional analytical maps of the single unit free-wave propagation domains (stop, pass and complex domains) provide the optimal choice of the cell properties and ordering. Moreover, the amount of vibration suppression along the periodic structure is also controlled as it can be described through iso-attenuation curves representing the contour plot of the real part of the propagation constants. Applications to both undamped and damped beams resting on elastic supports are illustrated. The response of the periodic structures to harmonic excitations is expressed through the wave vector method taking into account the effects of wave reflection due to changes in the cell properties along the structure and boundary conditions. Such computational schemes enables one to overcome numerical difficulties arising in the transfer matrix formulation for structures with a large number of periodic units. 相似文献
28.
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30.
Occhiuto I De Luca G Villari V Romeo A Micali N Pasternack RF Scolaro LM 《Chemical communications (Cambridge, England)》2011,47(21):6045-6047
Chirality is rapidly induced in a fractal aggregate of the porphyrin t-CuPagg by addition of α-helical poly-glutamate. These results demonstrate a facile transfer of chirality via noncovalent interactions to preformed supramolecular assemblies grown in the absence of a chiral template. 相似文献