Values Of Tr Research Articles

Unsteady Flow through a Rotating Curved Channel with Rectangular Cross-Section

A numerical study is presented for the fully developed two-dimensional thermal flow of viscous incompressible fluid through a rotating curved rectangular duct of constant curvature δ=0.1. In this paper, a spectral-based computational algorithm is employed as the principal tool for the simulations, while a Chebyshev polynomial, collocation method as secondary tools. Numerical calculations are carried out over a wide range of the Taylor number 0≤Tr≤2000 and the Dean number 100≤Dn≤2000 for the Grashof number Gr=500. The outer wall of the duct is heated while the inner wall is cooled. Unsteady flow structures are examined for the effects of rotation parameter and pressure-driven parameter, and it is found that the unsteady flow undergoes in the scenario ‘Chaotic→ multi-periodic→ periodic→ steady-state’, if Tr is increased in the positive direction. Contours of secondary flow patterns, temperature profiles and axial flow distribution are also obtained at several values of Tr, and it is found that there exist two- and multi-vortex solutions. It is also found that the temperature distribution is consistent with the secondary and axial vortices, and convective heat transfer is significantly enhanced as the secondary vortices become stronger.

The effect of loading rate on ductile fracture toughness and fracture surface roughness

The variation of ductile crack growth resistance and fracture surface roughness with loading rate is modeled under mode I plane strain, small scale yielding conditions. Three-dimensional calculations are carried out using an elastic–viscoplastic constitutive relation for a progressively cavitating solid with two populations of void nucleating second phase particles. Larger inclusions that result in void nucleation at an early stage are modeled as discrete void nucleation sites while smaller particles that require large strains to nucleate voids are homogeneously distributed. The calculations are carried out for two values of density of the larger inclusions, 3.6% and 7.1%, and for prescribed loading rates K̇̇I ranging from 1×105MPams−1 to 5×107MPams−1. The ductile fracture mode is found to undergo a transition from one that can be regarded as growth of a dominant main crack at the lower loading rates to one dominated by damage nucleation and micro-cracking ahead of the main crack at the higher loading rates. The values of JIC, the tearing modulus, TR, the total plastic dissipation and the plastic dissipation in the fracture process region are all found to increase with increasing loading rate. However, the ratio of plastic dissipation in the fracture process region to total plastic dissipation decreases with increasing prescribed loading rate. The fracture surfaces are found to display two self-affine regimes, with a Hurst exponent β≈0.60 at small length scales and with β≈0.45 at larger length scales. The multi-fractal spectra indicate multi-affine behavior in most cases but a range of loading rates and length scales exhibiting mono-affine behavior is also found. Parameters characterizing the fracture surface statistics, including the length scale at which a transition from a power law tail to an exponential tail occurs, are related to the mode of crack growth/damage accumulation. A linear relation is found between the values of JIC and TR and the saturation value of the correlation function of the surface roughness for K̇̇I<3×107MPams−1.

Combined Effects of Centrifugal and Coriolis Instability of the Flow Through a Rotating Curved Duct of Small Curvature

In this paper, a comprehensive numerical study is presented for the fully developed two-dimensional flow of viscous incompressible fluid through a rotating curved rectangular duct of small curvature. Numerical calculations are carried out by using a spectral method, and covering a wide range of the Taylor number 0≤Tr≤2000 for the Dean numbers Dn=500 and 1000. A temperature difference is applied across the vertical sidewalls for the Grashof number Gr=100, where the outer wall is heated and the inner wall cooled. The rotation of the duct about the center of curvature is imposed, and the effects of rotation (Coriolis force) on the unsteady flow characteristics are investigated. It is found that the unsteady flow undergoes in the scenario ‘Chaotic→ multi-periodic→ periodic → steady-state’, if Tr is increased in the positive direction. Contours of secondary flow patterns and temperature profiles are also obtained at several values of Tr, and it is found that there exist two- and multi-vortex solutions for the unsteady flow if the duct rotation is involved in the present cases.

The Solubility and Stability of Amino Acids in Biocompatible Ionic Liquids

In recent years, ionic liquids (ILs) represent a new class of biocompatible co-solvents for biomolecules. In this work, we report the apparent transfer free energies (ΔG'tr) for six amino acids (AA) from water to aqueous solutions of six ammonium based ILs (diethylammonium acetate (DEAA), diethylammonium sulfate (DEAS), triethyl ammonium acetate (TEAA), triethylammonium sulfate (TEAS), triethylammonium dihydrogen phosphate (TEAP), and trimethylammonium acetate (TMAA)) through solubility measurements, as a function of IL concentration at 298.15 K under atmospheric pressure. Salting-out effect was found for AA in aqueous IL solutions with increasing IL concentrations. In addition, we observed positive values of ΔG'tr for AA from water to ILs, indicating that the interactions between ILs and AA are unfavorable. From the obtained results, we found that the selected ammonium based ILs act as stabilizers for the structure of AA.

Transient Heat and Fluid Flow through a Rotating Curved Rectangular Duct: The Case of Positive and Negative Rotation

Abstract A comprehensive numerical study is presented for the fully developed two-dimensional thermal flow of viscous incompressible fluid through a rotating curved rectangular duct of constant curvature δ=0.1 Numerical calculations are carried out by using a spectral method, and covering a wide range of the Taylor number -1000 ≤ Tr ≤ 3000 and the Dean number 100≤ Dn ≤1000 for the Grashof number Gr 100. The outer wall of the duct is heated while the inner wall cooled. Flow characteristics are investigated for two cases of the duct rotation, Case I : Positive rotation and Case II : Negative rotation. For positive rotation, we investigate the unsteady flow characteristics for the Taylor number 0≤ Tr ≤3000 and it is found that the unsteady flow undergoes in the scenario ‘ Chaotic→multi-periodic → periodic → steady-state’ , if Tr is increased in the positive direction. For negative rotation, however, we investigate the unsteady flow behavior for 1000≤ Tr ≤100, and it is found that the unsteady flow undergoes through various flow instabilities, if Tr is increased in the negative direction. Contours of secondary flow patterns and temperature profiles are also obtained at several values of Tr , and it is found that there exist two- and multi-vortex solutions if the duct rotation is involved in both the directions.

Surface plasmon polariton enhanced electroluminescence and electron emission from electroformed Al-Al2O3-Ag diodes

Electroforming of Al-Al2O3-Ag diodes results in voltage-controlled negative resistance (VCNR) in the current-voltage (I-V) curves. Electroluminescence (EL) and electron emission into vacuum (EM) develop simultaneously. The temperature dependence between 200 and 300 K of VCNR, EL, and EM of Al-Al2O3-Ag diodes with anodic Al2O3 thicknesses between 12 and 41 nm has been studied. I-V curves and VCNR are slightly temperature dependent. The voltage for the onset of EL, VEL, is between ∼1.3 and ∼1.9 V for the range of Al2O3 thicknesses, with small temperature dependence. The density of defects in anodic Al2O3 is &amp;gt;1.5 × 1020 cm−3. Defect conduction bands that form from excited states of F- or F+-centers, oxygen vacancies in Al2O3, determine the value of the barrier height at the Al-Al2O3 interface, ϕA, and they control EM. EM is anomalous. The threshold voltage for EM, VEM, is ∼1.9 to ∼2.5 V for the range of Al2O3 thicknesses, which is less than the work function of Ag, 4.6 eV. EM at 300 K is ∼10−9 A. As temperature is lowered, EM drops to ∼10−12 A at TD ≅ 290 K and recovers to ∼10−9 A at TR ≅ 260 K. The particular values of TD and TR depend on sample preparation and Al2O3 thickness. The source of anomalous EM is electrons that tunnel through the high field region at the Al-Al2O3 interface into defect conduction bands. They gain energy and momentum by combining with surface plasmon polaritons (SPPs) that are generated at the Al2O3-Ag interface by EL photons. EL from Al-Al2O3-Ag diodes with 12 nm or 15 nm of Al2O3 is much larger than EL from diodes with thicker Al2O3 layers. The conducting channel of electroformed diodes with the thinnest Al2O3 acts as a microcavity in which the electromagnetic field due to SPPs stimulates EL from defect centers by the Purcell effect.

TH-E-BRA-09: Radiation Induced Current Effects on MR Images from an Integrated Linac-MR System

Purpose: During the real-time MR image acquisition of an integrated linac/MRI system, the MRI's RF coils is exposed to pulsed radiation resulting in radiation induced currents (RIC). This work will: (a) visualize the RIC signal as artefacts in k-space and determine its effect on MRI's signal-to-noise ratio (SNR), (b) examine the effects of linac repetition rate (MU/minute) and MRI imaging sequence parameter ‘TR’ on the RIC artefact, (c) use post processing methods to remove the unwanted RIC signal from the MR images. Methods: A small test phantom was imaged with no radiation first. Phantom imaging was then repeated concurrently with linac producing radiation at various repetition rates in two scenarios: (1) the radiation beam was incident on the RF coil unobstructed and (2) a lead block attenuated the radiation beam before reaching the RF coil. Scenario (1) was repeated by obtaining images for several values of TR. Finally, a post-processing algorithm was applied to the corrupted MR k-space data to remove the RIC artefact. Results: The RIC artefact presented as near vertical lines in k-space data for integer ratios of TR to linac pulsing period (rate =180 Hz). For non-integer ratios, the artefact lost its regular pattern and became random in appearance. The RIC artefact disappeared from the k-space data when the linac's radiation was blocked. The image SNR decreased with increasing linac repetition rate. The post-processing method was successful in restoring a significant fraction of the lost image SNR. Conclusions: Signal spikes observed in the k-space data are confirmed to result from RIC. The SNR reduction in MRI images, due to the RIC, is directly related to the linac repetition rate. The artefact's appearance depends on the relationship between linac pulse repetition rate and image sequence timing. Our post-processing algorithm allows the recovery of the lost image SNR. The financial support is provided by the Canadian Institute of Health Research operating grant # MOP 93752.

Competitive partitioning of rotational energy in gas ensemble equilibration

A wide-ranging computational study of equilibration in binary mixtures of diatomic gases reveals the existence of competition between the constituent species for the orbital angular momentum and energy available on collision with the bath gas. The ensembles consist of a bath gas AB(v;j), and a highly excited minor component CD(v';j'), present in the ratio AB:CD = 10:1. Each ensemble contains 8000 molecules. Rotational temperatures (T(r)) are found to differ widely at equilibration with T(r)(AB)/T(r)(CD) varying from 2.74 to 0.92, indicating unequal partitioning of rotational energy and angular momentum between the two species. Unusually, low values of T(r) are found generally to be associated with diatomics of low reduced mass. To test effects of the equi-partition theorem on low T(r) we undertook calculations on HF(6;4) in N(2)(0;10) over the range 100-2000 K. No significant change in T(r)(N2)/T(r)(HF) was found. Two potential sources of rotational inequality are examined in detail. The first is possible asymmetry of -Δj and +Δj probabilities for molecules in mid- to high j states resulting from the quadratic dependence of rotational energy on j. The second is the efficiency of conversion of orbital angular momentum, generated on collision with bath gas molecules, into molecular rotation. Comparison of these two possible effects with computed T(r)(AB)/T(r)(CD) shows the efficiency factor to be an excellent predictor of partitioning between the two species. Our finding that T(r) values for molecules such as HF and OH are considerably lower than other modal temperatures suggests that the determination of gas ensemble temperatures from Boltzmann fits to rotational distributions of diatomics of low reduced mass may require a degree of caution.

Effects of &lt;i&gt;LHSV&lt;/i&gt; and Reaction Temperature upon Ethanol-Steam-Reforming Performance

Supposing the design of ethanol steam-reforming reactors, the authors conduct experiments for Cu/ZnO/Al2O3 catalyst. Using a household-use-scale reactor with well-controlled temperature distributions, the authors compare experimental results with chemical-equilibrium theories. It has revealed by Shinoki et al. (2011) that Cu/ZnO/Al2O3 catalyst shows rather high performance with high hydrogen concentration CH2 at low values of reaction temperature TR. So, in the present study, the authors reveal the influences of liquid-hourly space velocity LHSV upon concentrations such as CH2, CCO2, CCO and CCH4 and the influence of LHSV upon the ethanol conversion XC2H5OH, in a range of LHSV from 0.05 h-1 to 0.8 h-1, at S/C = 3.0 and TR = 520 K. And, the authors reveal the influences of the thermal profile upon CH2, CCO2, CCO, CCH4 and XC2H5OH, for several LHSV's. To conclude, with well-controlled temperatures, the reformed gas can be close to the theory.

Effect of long‐term water immersion on the fracture toughness of denture base and reline resins

This study evaluated the fracture toughness (FT) of one denture base (Lucitone 550 - L) and four hard reline resins [Ufi Gel Hard (UH), Tokuyama Rebase II (TR), New Truliner (NT) and Kooliner (K)], and the effect of long-term water storage on this property. Forty specimens (40 × 8 × 4 mm) of each material were made, and FT was assessed after polymerisation (control of reliners), after 48 ± 2 h in water at 37°C (control of denture base resin) and after storage in water at 37°C for 7, 90 or 180 days (all materials). Data (MPa.m(1/2) ) were analysed by two-way anova and Games-Howell test (p = 0.05). Resin L exhibited the highest FT mean values. After 180 days of storage, FT mean values of L (3.37), UH (1.53) and K (1.20) were higher than those of the other periods. FT mean values of NT decreased from control (1.63) to 7 days (1.30) and then remained constant. FT mean values of TR (1.13) were similar in all periods of analysis. The denture base resin L showed higher FT mean values than the reline resins. Long-term water storage increased the FT of L, UH and K, reduced the FT of NT and did not influence the FT of TR.

Cellular convection in a chamber with a warm surface raft

We calculate velocity and temperature fields for Rayleigh-Benard convection in a chamber with a warm raft that floats along the top surface for Rayleigh number up to Ra = 20 000. Two-dimensional, infinite Prandtl number, Boussinesq approximation equations are numerically advanced in time from a motionless state in a chamber of length L′ and depth D′. We consider cases with an insulated raft and a raft of fixed temperature. Either oscillatory or stationary flow exists. In the case with an insulated raft over a fluid, there are only three parameters that govern the system: Rayleigh number (Ra), scaled chamber length (L = L′/D′), and scaled raft width (W). For W = 0 and L = 1, linear theory shows that the marginal state without a raft is at a Rayleigh number of 23π4=779.3, but we find that for the smallest W (determined by numerical grid size) the raft approaches the center monotonically in time for Ra&amp;lt;790. For 790&amp;lt;Ra&amp;lt;811, the raft has a decaying oscillation consisting of raft movement back and forth accompanied by convection cell reversal. For 811&amp;lt;Ra&amp;lt;871, the oscillation amplitude is constant in time and it increases with larger Ra. Finally, there is no raft motion for Ra&amp;gt;871. For larger raft widths, there is a range of W that produces raft oscillation at each Ra up to 20 000. Rafts in longer cavities (L = 2 and 4) have almost no oscillatory behavior. With a raft of temperature set to different values of Tr rather than insulating, a fixed Rayleigh number Ra=20000, a square chamber (L = 1), fixed raft width, and with internal heat generation, there are two ranges of oscillating flow.

Weight loss and changes in surface roughness of denture base and reline materials after simulated toothbrushing in vitro

To evaluate the weight loss and the surface roughness of acrylic resins after simulated brushing tests. Ten specimens of each material (Tokuyama Rebase II-TR, New Truliner-NT, Ufi Gel Hard-UH and Lucitone 550-L) were made. The wear loss (mg) by weight and the surface roughness (Ra μm) of each specimen was determined before and after brushing. The specimens were placed on the brushing machine and a total of 20,000 brushing cycles was performed. The results of weight loss and roughness values were submitted to the anova followed by the Tukey's test (p = 0.05). The mean weight loss of material L was statistically higher (p < 0.001) than that of the relines TR, UH and NT. No significant differences were found among the roughness values of resins TR, UH and L (p > 0.05). Only for L, toothbrushing increased the surface roughness. After toothbrushing, there was no significant difference between the roughness values of materials L and NT. The highest mean weight loss during the simulated toothbrushing tests was observed for L. Before the toothbrushing tests, the NT exhibited the highest mean roughness. Brushing resulted in increase in roughness only for resin L.

Abnormal Ductus Venosus Flow and Tricuspid Regurgitation at 11–14 Weeks' Gestation have High Positive Predictive Values for Increased Risk in First-Trimester Combined Screening Test: Results of a Pilot Study

To investigate the relationship between two novel first-trimester ultrasound markers (abnormal fetal ductus venosus [DV] flow and presence of tricuspid regurgitation [TR]) and the results of the first-trimester combined screening test in pregnancies with a normal karyotype. The screening test involves nuchal translucency measurement by ultrasound, and measurement of serum free beta-chorionic gonadotropin and pregnancyassociated plasma protein A. The study included 58 pregnancies with amniocentesis-proven normal karyotypes and ultrasound-proven normal fetal anatomy. DV flow and TR were initially evaluated by ultrasound at 11-14 weeks' gestation. Sensitivity, specificity, and positive and negative predictive values of abnormal DV flow and TR for determining increased test risk (> 1 in 300) were calculated. Abnormal DV flow and TR were detected in seven (12%) and six (10%) women, respectively. The sensitivities of abnormal DV flow, TR, and dual abnormalities (abnormal DV flow plus TR) for predicting increased risk in the combined screening test were low (33.3%, 27.7%, and 26.3%, respectively). However, their corresponding specificities (97.5%, 97.5%, and 100%) and positive predictive values (85.7%, 83.3%, and 100%) were reasonably high, with particularly low false-positive rates (2.5%, 2.5%, and 0%). When abnormal DV flow and TR were both positive, the combined test risk was consistently above 1 in 300. Determination of DV flow and TR as initial markers in unselected pregnancies merits further investigation, as the combination of these parameters might reliably predict an increased risk in combined screening test result, with low false positivity.

Foliar responses to ozone of Fagus sylvatica L. seedlings grown in shaded and in full sunlight conditions

Ozone (O 3) is well known to affect photosynthesis on tree seedlings under experimental conditions. In natural conditions, young trees grow under a competitive environment that may alter light availability. Such conditions were simulated in an open-top chamber (OTC) experiment carried out in Southern Switzerland (Lattecaldo). The experimental set-up consisted of Fagus sylvatica (beech) seedling plots (planted within the same chamber) either in a monospecific population (Mono, leaves grown in full sunlight conditions—FL) or under competition with taller plants of Viburnum lantana (Mixed, shaded leaves—SH). These cultures were treated with ambient air (NF, not filtered, 92% of ozone in ambient air) and with charcoal filtered air (CF, 50% of ozone in ambient air). Measures of net photosynthesis ( P N) and chlorophyll a fluorescence (with the analysis of the OKJIP transient) were performed over a growing season, from June to September. Net photosynthesis ( P N) and the maximum quantum yield of electrons reaching the acceptor side ( φ Ro = RE 0/ABS) were higher in Mono conditions (full light leaves). Vice versa, quantum yield of primary photochemistry ( φ Po = TR 0/ABS = F V/ F M) and Performance Index on absorption basis (PI ABS) were higher in Mixed plots (shaded leaves). Changes due to ozone occurred only at the end of the growing season (September). Ozone affected mainly P N, that was lower in the NF-OTCs, both Mono (−19%) and Mixed (−28%) plots, compared to the CF ones. Fluorescence parameters were affected much more by light conditions (full light vs. shaded leaves) than ozone exposure, but ozone enhanced the action of high light by lowering the values of TR 0/ABS and PI ABS. The most specific effect of ozone concerned the decrease in RE 0/ABS, that indicates the inactivation of the end acceptors of electrons, so producing an excess of oxidative pressure. Results are discussed in relation to the impact of ozone on the processes of the regeneration of forests.

Comparative study of the electro-transport characteristics of chalcogenate and chalcogenite ions in aqueous solutions

A comparative study of the temperature and concentration dependence of the equivalent conductivity has been carried out in aqueous solutions of sulphuric acid, selenic acid, potassium tellurate, sodium selenite and potassium tellurite. A temperature dependence of the equivalent conductivity has been established at infinite dilution of the chalcogenate and chalcogenite ions in aqueous solutions within the temperature interval 15–45°C. The diffusion coefficients, the absolute motion velocities, the Stock's radii and the hydration numbers have been calculated for the following ions: , , , and . The differences of the electro-transport characteristics between the chalcogenate and chalcogenite ions are contributed to the fact that they are of different sizes, and some linear dependences on the ion radii have been established for the equivalent conductivity at infinite dilution and the diffusion coefficients. The values of the translation energy ΔE tr.○ have been calculated for the water molecules in the hydration shell of the ions within the temperature interval, mentioned above. A tendency of increasing the values of has been observed with the increment of the temperature and the ion radius.

Comparative study on the films of poly(vinyl alcohol)/pea starch nanocrystals and poly(vinyl alcohol)/native pea starch

Pea starch nanocrystals (PSN) dispersion containing nanocrystals in a range of 30–80 nm was prepared from native pea starch (NPS) granules by acid hydrolysis. Two series of films were prepared by blending poly(vinyl alcohol) (PVA) with NPS and PSN, respectively. The effects of NPS and PSN on the structure and properties of the resulting films were comparatively investigated by FTIR, XRD, SEM, and testing of light transmittance, tensile, and moisture uptake. The light transmittance (Tr), tensile strength ( σ b), and elongation at break ( ε b) of the PVA/NPS films were lower than that of PVA film and decreased with an increase in NPS content. However, the PVA/PSN nanocomposite films containing 5 and 10 wt% of PSN content exhibited improved physical properties over the PVA film. The PVA/PSN films showed higher Tr, σ b, and ε b, and lower moisture uptake (Mu) than the corresponding PVA/NPS films with the same component ration. For example, the values of Tr, σ b, ε b, and Mu of the PVA/PSN film containing 10 wt% of PSN content were 91%, 40 MPa, 734% and 71%, respectively; while those of the corresponding PVA/NPS film were 69%, 35 MPa, 579% and 73%, respectively. The results revealed that PSN, comparing with NPS, had much smaller sizes and dispersed more homogeneously in PVA matrix, resulting in stronger interactions with PVA. New applications of native pea starch and its nanocrystals as low-cost fillers were explored in this work, and PSN exhibited greater potential than NPS to improve the properties of PVA-based composites.

Probing binding site of bacteriochlorophyll a and carotenoid in the reconstituted LH1 complex from Rhodospirillum rubrum S1 by Stark spectroscopy

Stark spectroscopy is a powerful technique to investigate the electrostatic interactions between pigments as well as between the pigments and the proteins in photosynthetic pigment-protein complexes. In this study, Stark spectroscopy has been used to determine two nonlinear optical parameters (polarizability change Tr(Deltaalpha) and static dipole-moment change |Deltamu| upon photoexcitation) of isolated and of reconstituted LH1 complexes from the purple photosynthetic bacterium, Rhodospirillum (Rs.) rubrum. The integral LH1 complex was prepared from Rs. rubrum S1, while the reconstituted complex was assembled by addition of purified carotenoid (all-trans-spirilloxanthin) to the monomeric subunit of LH1 from Rs. rubrum S1. The reconstituted LH1 complex has its Q(y) absorption maximum at 878 nm. This is shifted to the blue by 3 nm in comparison to the isolated LH1 complex. The energy transfer efficiency from carotenoid to bacteriochlorophyll a (BChl a), which was determined by fluorescence excitation spectroscopy of the reconstituted LH1 complex, is increased to 40%, while the efficiency in the isolated LH1 complex is only 28%. Based on the differences in the values of Tr(Deltaalpha) and |Deltamu|, between these two preparations, we can calculate the change in the electric field around the BChl a molecules in the two situations to be E (Delta) approximately 3.4 x 10(5) [V/cm]. This change can explain the 3 nm wavelength shift of the Q(y) absorption band in the reconstituted LH1 complex.

SU‐FF‐I‐58: Demonstration of the Use of A Capillary Phantom to Monitor DTI Image Processing: Dyadic Sorting of Tensor Eigenvalues

Purpose: To verify the existence of noise‐dependent systematic bias in diffusion tensor imaging (DTI) data using a phantom composed of arrays of glass capillary fibers; and to use the phantom to monitor the corrective effect of using dyadic sorting for alleviating this bias when calculating average quantities in a region of interest (ROI). Method and Materials: A phantom containing glass capillary arrays and undoped water was constructed. Seventeen DTI series of images from a 3.0T GE scanner were acquired, where TR was adjusted between series to vary the signal intensity via T1 contrast. Five different values of TR were chosen. Averaging of some of these series together allowed for observations at eight unique values of SNR. Eigenvalues and eigenvectors of the diffusion tensor were calculated as well as fractional anisotropy. After calculation of the average eigenvalues and eigenvectors in ROIs containing the arrays and free water, these average values were used to sort eigenvector‐eigenvalue dyadic pairs to maximize overlap between the average values and individual voxel values. Final averages were calculated after sorting. Results: Noise‐dependent bias was observed using arrays of fibers, resulting in a separation of the two lowest eigenvalues which should be equivalent. Dyadic sorting assists with correcting this bias, although usefulness is confined to regions of lower FA and with higher SNR. Iterative sorting does not greatly improve the performance. Conclusion: This work suggests that glass capillary arrays can be used for monitoring systematic bias at a variety of SNR values, and for quantifying the amount of correction that one will observe using a particular scheme, in principle. Future investigation will examine the efficacy of other correction schemes.

Differential Diagnosis of Focal Nodular Hyperplasia With Quantitative Parametric Analysis in Contrast-Enhanced Sonography

We investigated the potential of quantitative parametric analysis in the differential diagnosis of focal nodular hyperplasia (FNH) from other hypervascularized liver focal lesions. Eighty-five focal liver lesions (in 83 patients) were explored using contrast-enhanced ultrasound (SonoVue and Cadence Contrast Pulse Sequencing) consisting of typical FNH (n=52), hepatocellular carcinoma (n=11), hemangioma with high flow (n=8), hypervascular metastases (n=10), and hepatocellular adenoma (n=4). QontraXt software (AMID, Italy) was used here to estimate the following parameters: maximum peak value, Tr (time corresponding to time for obtaining 63% of the plateau), beta parameter corresponding to the exponential factor, and slope corresponding to the tangent value of the first phase of enhancement. These parameters were obtained from the time-intensity curves derived from the enhancement observed in 2 regions of interest corresponding, respectively, to the whole lesion and the central region only. A significant statistical difference (P<0.05) was found in the values of Tr, beta, and slope between FNH and other hypervascularized lesions on both the whole lesion and central region. Among these parameters, slope appeared as the most valuable whatever the region of interest, ie, central or whole lesion (P<0.01). Central region was more accurate in the differentiation of FNH and concordant with visual characterization. Quantitative parametric curve analysis of the different hypervascularized lesions confirms the depiction of the central artery in FNH and thus could help in differentiating this specific focal liver lesion from the others.

Arterial blood gas analysis in Lipopolysaccharide-heat co-stressed rats

To observe the change in vital signs and arterial blood gas in Lipopolysaccharide (LPS)-injected heat exposed rats. Male pathogen-free Wistar rats were randomly assigned to the following groups: saline-injected normothermic control (C-Group), saline-injected heat exposed (H-Group), LPS-injected normothermic control (L-Group), LPS-injected heat exposed (HL-Group). Rectal temperature (Tr), heart rate (HR), mean arterial pressure (MAP), arterial blood gas were continually monitored. (1) The rats in HL-Group displayed significantly high values of Tr (43.04 degrees C +/- 0.11 degrees C) and HR [(660 +/- 42) beats/min] and low values of MAP [(49.0 +/- 3.5) mm Hg] compared with C-Group. There was a significant difference in the values of Tr, HR, and MAP between HL-Group and L-Group and in the values of HR and MAP between HL-Group and H-Group. (2) The values of PaO(2), HCO(3)(-), PaCO(2) were significantly lower than those in C-Group at 40 min after LPS-injected heat stress. At 120 min, the PaO(2) [(11.59 +/- 1.11) kPa], HCO(3)(-) [(10.42 +/- 1.06) mmol/L], PaCO(2) [(2.82 +/- 0.81) kPa] in HL-Group were significantly lower than those in L-Group. A significant difference in the values of HCO(3)(-) and PaCO(2) between HL-Group and H-Group was also observed. LPS-injected heat stress primes the rat to advance and augment the change in vital signs, arterial blood gas, and systemic inflammatory response syndrome.