5,323,318 research outputs found
Comparison of regional blood flow values measured by radioactive and fluorescent microspheres
Fluorescent microspheres (FM) have become an attractive alternative to radioactive microspheres (RM) for the measurement of regional blood flow (RBF). The aim of the present study was to investigate the comparability of both methods by measuring RBF with FM and RM. Eight anaesthetised pigs received simultaneous, left atrial injections of FM and RM with a diameter of 15 mum at six different time points. Blood reference samples were collected from the descending aorta. RBF was determined in tissue samples of the myocardium, spleen and kidneys of all 8 animals. After radioactivity of the tissue samples was determined, the samples were processed automatically for measuring fluorescence using a recently developed filter device (SPU). RBF was calculated with both the isotope and spectrometric data of both methods for each sample resulting in a total of 10,512 blood flow values. The comparison of the RBF values yielded high linear correlation (mean r(2) = 0.95 +/- 0.03 to 0.97 +/- 0.02) and excellent agreement (bias 5.4-6.7%, precision 9.9-16.5%) of both methods. Our results indicate the validity of MS and of the automated tissue processing technique by means of the SPU. Copyright (C) 2002 S. Karger AG, Basel
Influence of seismic senzor setting on measured values
Import 29/09/2010Zadání bakalářské práce bylo zjistit, jaký vliv má ustavení seizmického senzoru na kvalitu odečítaných hodnot. Součástí bylo vypracovat rešerši o historii, principu a využití seizmických senzorů. Hlavní důraz byl kladen na sestavení pokusu k určení vlivu ustavení senzoru. Pokus sestával ze sestrojení nakloněné roviny a generátoru kmitů. Při realizaci pokusu jsem se nejen seznámil se s měřící aparaturou, ale také jsem získal praktické zkušenosti s prováděním měření. Provedl jsem dvě měření a jejich vyhodnocení. Ve vyhodnocení jsem uvedl naměřené hodnoty a zhodnotil také nepředpokládané zdroje chyb ovlivňující výsledky.Main aim of presented bachelor´s thesis was to determine influence of seismic sensor setting on quality of measured values. Integral part of this thesis was elaboration of background research about history, principle and usage of seismic sensors. Main emphasis was localized on methodology and realization of experimental measurements for determination of seismic sensor setting. Design of inclined plane and realization of oscillation generator represent main preliminary works. I learned with measuring seismological apparatus during experiments and I also obtained operative experiences with preparation and realization of seismological measurements. I performed two measurements and their interpretations. I summarized not only measured values from several tests but I also evaluate nonscheduled sources of mistakes, which influenced obtained results.Prezenční224 - Katedra geotechniky a podzemního stavitelstvívýborn
Simulating solute transport in an aggregated soil with the dual-porosity model: measured and optimized parameter values
The capability of the first-order, dual-porosity model, which explicitly accounts for non-ideal transport caused by the presence of ‘immobile’ water, to predict the non-ideal transport of non-sorbing solute in a constructed aggregated soil has been investigated. Miscible-displacement experiments performed with a well-characterized aggregated soil and a non-reactive tracer (pentafluorobenzoate) served as the source of the data. Values for the input parameters associated with physical non-equilibrium were determined independently and compared with values obtained by curve fitting of the experimental measurements. The calculated and optimized values compared well, suggesting that the non-equilibrium parameters represent actual physical phenomen
Comparing Protonolysis and Transmetalation Reactions: Microcalorimetric Studies of C–AuI Bonds in [AuRL] Complexes
Producción CientíficaThe protonolysis of C–Au bonds in [AuRL] organometallic complexes
has been studied by calorimetry for twelve R groups. The experimental data
have been combined with DFT calculations to obtain Bond Dissociation Energy
values (BDE). The C–Au BDE values show a good correlation with the corresponding
isolobal C–H BDE values. The heat released in the protonolysis of
[AuRL] has also been measured for R = Ph and L = P(OPh)3, PPh3, PMe3, PCy3,
and IPr, and these values strongly depend on the trans influence of L because of the
mutual destabilization of the L–Au and Au–C bonds. The enthalpy of the
transmetalation reactions [AuR(PPh3)] + SnIBu3 → [AuI(PPh3)] + SnRBu3 for
seven R groups have been measured and compared with the corresponding
[AuR(PPh3)] protonolysis.Ministerio de Economía, Industria y Competitividad (Project CTQ2016-80913-P)Junta de Castilla y León (Project VA 051P17
Drop rebound in clouds and precipitation
The possibility of rebound for colliding cloud drops was measured by determining the collection efficiency. The collection efficiency for 17 size pairs of relatively uncharged drops in over 500 experimental runs was measured using two techniques. The collection efficiencies fall in a narrow range of 0.60 to 0.70 even though the collection drop was varied between 63 and 326 microns and the size ratio from 0.05 to 0.33. In addition the measured values of collection efficiencies (Epsilon) were below the computed values of collision efficiencies (E) for rigid spheres. Therefore it was concluded that rebound was occurring for these sizes since inferred coalescence (epsilon = Epsilon/E) efficiencies are about 0.6 yo 0.8. At a very small size ratio (r/R = p = 0.05, R = 326 microns) the coalescence efficiency inferred is in good agreement with the experimental findings for a supported collector drop. At somewhat large size ratios the inferred values of epsilon are well above results of supported drop experiments, but show a slight correspondence in collected drop size dependency to two models of drop rebound. At a large size ratio (p = 0.73, R = 275) the inferred coalescence efficiency is significantly different from all previous results
Neutral Gauge Boson Contributions to the Dimuon Charge Asymmetry in B Decays
Recently, the D0 Collaboration measured the CP-violating like-sign dimuon
charge asymmetry in neutral B decays, finding a 3.2sigma difference from the
standard-model (SM) prediction. A non-SM charge asymmetry a_sl^s suggests a
new-physics (NP) contribution to Bs-Bsbar mixing. In this case, in order to
explain the measured value of a_sl^s within its 1sigma range, NP must be
present in Gamma_12^s, the absorptive part of the mixing. In this paper, we
examine whether such an explanation is possible in models with flavor-changing
Z (ZFCNC) or Z' (Z'FCNC) gauge bosons. The models must also reproduce the
measured values of the indirect CP asymmetry S_psi-phi in Bs -> J/psi phi, and
Delta Gamma_s, the Bs-Bsbar width difference. We find that the ZFCNC model
cannot reproduce the present measured values of S_psi-phi and a_sl^s within
their 1sigma ranges. On the other hand, in the Z'FCNC model, the values of all
three observables can be simultaneously reproduced.Comment: 18 pages, 7 figures, JHEP format. Some ZFCNC equations corrected,
ZFCNC analysis redone, references added, conclusions unchange
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