1,841 research outputs found
Prediction of the surface tension of mixed electrolyte solutions based on the equation of Patwardhan and Kumar and the fundamental Butler equations
No full textThe predictive equation of Patwardhan and Kumar for the water activity of mixed electrolyte solutions has been used together with the fundamental Butler equations to establish a new simple predictive equation for the surface tension of mixed electrolyte solutions. This newly proposed equation can provide the surface tensions of multicomponent solutions using only the data of the corresponding binary subsystems of equal ionic strength. No binary interaction parameters are required. The predictive capability of the equation has been tested with the experimental data for 26 concentrated multicomponent electrolyte solutions at different temperatures and compared with the model of Li et al. Both equations agree well with the experimental results of systems examined over entire experimental composition ranges, but the new equation generally gives better predictions for most 1:1 electrolyte systems examined, and considerable improvement in predictions has been achieved for all the mixtures containing 1:2 and 2:2 electrolytes and for 1:1 electrolyte systems at higher temperatures. (C) 2003 Elsevier Inc. All rights reserved
Prediction of viscosity of mixed electrolyte solutions based on the Eyrings absolute rate theory and the semi-ideal hydration model
No full textThe mixing behavior of viscosities of electrolyte solutions under isopiestic equilibrium has been studied for the first time using the Eyring's absolute rate theory and the semi-ideal hydration model. The concentration dependence of the change in molar free energy of activation for flow has been formulated and discussed based on the concept of average hydration number and the structure-making or structure-breaking nature of the ion species. Coupling of the Erying's theory and the semi-ideal hydration model yields very simple mixing behavior of viscosities of electrolyte solutions under isopiestic conditions and thus yields new simple equations for viscosity, which can provide predictions for mixed solutions using only information on the single solute solutions. The new equations have been tested by comparisons with the experimental results for 15 systems and the existing equations reported in literature. The present equations improve the predictions considerably and the agreement with experimental results is in general quite good. The effect of different contributions accompanying the mixing process on the predicted results has been studied. The viscosities of the mixed electrolyte solutions can be well predicted only by using the additive contribution from the viscosities of binary solutions under isopiestic condition. The addition of the mixing term in this simple additive equation yields better predictions for mixed solutions mainly consisting of the structure-making ions. The inclusion of the density term has little effect on the predicted results. (C) 2003 Elsevier Science Ltd. All rights reserved
Comparison of vestibular function between large-sized cerebellopontine angle meningioma and schwannoma
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Tolerance and humoral immune response to the yellow fever vaccine in sickle cell disease children treated with hydroxyurea: a multicentre prospective study
No full textInternational audienceBackgroundSickle cell disease (SCD) children are frequent travellers to countries where yellow fever (YF) is endemic, but there are no data regarding the safety and immunogenicity of the vaccine in such children treated with hydroxyurea (HU). The main objective of this study was to compare the tolerance and immune response to YF vaccination in SCD children treated or not with HU.MethodSCD children < 18 years attending the international travel clinics of three large paediatric centres and requiring a first YF vaccination were included in a prospective study. Adverse events were collected 2 weeks after vaccination. YF vaccine antibody titres were measured ~6 months after vaccination.ResultsAmong the 52 SCD children vaccinated against YF, 17 (33%) were treated with HU. Only mild adverse events, mainly fever and local reaction, were observed in the HU group with a similar frequency in the non-HU group (57 and 35%, respectively, P = 0.30). YF antibody titres were measured in 15/17 patients in the HU group and 23/35 patients in the non-HU group after a median of 6.0 months (3.5–8.5) following vaccination. The geometric mean of YF antibody titre was similar in both groups. A protective antibody level was observed in 85% of the children in the HU group vs 100% in the non-HU group (P = 0.14), suggesting a lower effectiveness of the vaccine in patients on HU similarly to what has been described in patients on immune suppressive therapy for other vaccines.ConclusionYF vaccination seems to be safe and efficient in SCD children treated with HU. Considering the potential risk of severe complications in cases of YF while travelling in Africa for those patients, the benefit-to-risk ratio argues for YF vaccination in all SCD children. Control of a protective antibody titre may also be useful to ascertain an adequate response in those treated with HU
SAPS 3 at dialysis commencement is predictive of hospital mortality in patients supported by extracorporeal membrane oxygenation and acute dialysis
No full textSilicon nanostructured films formed by pulsed-laser deposition in inert gas and reactive gas
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Harvesting the Hidden Energy for Self-powered Systems
No full textEnergy harvesting technologies based on piezoelectric properties of nanomaterials and triboelectric phenomenon between two different materials are superior candidates for random mechanical energy harvesting in the environment. Self-powered system integrated with such kind of energy harvesting module and multi-functional nanodevices have great application potentials in the independent, sustainable, maintenance-free operations of implantable biosensors, remote and mobile environmental sensors, nanorobotics, microelectromechanical systems, and even portable/wearable personal electronics. Several recent progresses are summarized here.BES DOE [DE-FG02-07ER46394]; DARPA [HR0011-09-C-0142]; NSF [CMMI 0403671]; MURI from the AirforceCPCI-S(ISTP)[email protected]
A SIMPLE DIGITAL WATERMARKING BY THE ADAPTIVE BIT-LABELING SCHEME
No full text[[abstract]]Based on integer wavelet transform (IWT), this study proposes a novel data hiding technique via the adaptive bit-labeling scheme The proposed method includes bit-marking, modulus-2, and coefficient-bias steps More specifically, a small (primary) watermark is first embedded in the three high subbands of the L1 IWT by bit-marking as well as in the L2 and L3 IWT by modulus-2 A large message, which is also known as the secondary watermark, is then hidden in the high subbands of the L1 IWT using the coefficient-bias To promote robustness performance, instead of hiding bits directly in the blocks, the authors use an adaptive bit-labeling scheme to a block, which could correctly signify the hidden bits at the receiver. Simulations show that the primary watermark hidden in stego-images generated by the proposed method are robust against manipulations such as JPEG2000, JPEG, cropping, (color) quantization, noise additions, low-pass filtering, (edge) sharpening, brightness, contrast, winding and inverting Experiments also confirm that under the condition of attacking-free the secondary watermark can be successfully extracted by the decoder Moreover, the perceived quality of the resulting images is good[[note]]SC
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