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Early post-operative delirium is a common perioperative complication in the post anesthesia care unit. To date it is unknown if a specific anesthetic regime can affect the incidence of delirium after surgery. Our objective was to examine the effect of volatile anesthetics on post-operative delirium.Single Center Observational Study.Post Anesthesia Care Units at a German tertiary medical center.30,075 patients receiving general anesthesia for surgery.Delirium was assessed with the Nursing Delirium Screening Scale at the end of the recovery period. Subgroup-specific effects of volatile anesthetics on post-operative delirium were estimated using generalized-linear-model trees with inverse probability of treatment weighting. We further assessed the age-specific effect of volatiles using logistic regression models.Out of 30,075 records, 956 patients (3.2%) developed delirium in the post anesthesia care unit. On average, patients who developed delirium were older than patients without delirium. We found volatile anesthetics to increase the risk (Odds exp. (B) for delirium in the elderly 1.8-fold compared to total intravenous anesthesia. Odds increases with unplanned surgery 3.0-fold. In the very old (87 years or older), the increase in delirium is 6.2-fold. This result was confirmed with internal validation and in a logistic regression model.Our exploratory study indicates that early postoperative delirium is associated with the use of volatile anesthetics especially in the sub-cohort of patients aged 75 years and above. Further studies should include both volatile and intravenous anesthetics to find the ideal anesthetic in elderly patients.

This paper evaluates the use of a phase change composite (PCC) material consisting of paraffin wax (n-Tetradecane) and expanded graphite as a potential storage medium for cold thermal energy storage (TES) systems to support air conditioning applications. The PCC-TES system is proposed to be integrated with the vapor compression refrigeration cycle of an air conditioning (AC) system. The use of this PCC material is novel because of its unique material and thermal characteristics as compared to ice or chilled water that are predominantly used in commercial TES systems for air cooling applications. The work of this paper proposed and tested a hypothesis, which suggests that integrating a conventional AC with a PCC-TES would result in significant benefits concerning compressor size, compressor efficiency, electricity consumed and CO2 emissions. The proposed integration would also contribute to reduce electricity demand during peak hours and reduce necessity to build more expensive power plants and distribution lines. To test the hypothesis, a simulation model in Aspen Plus® software was prepared. However, Aspen Plus® does not have a built-in library to predict PCC’s melting and solidification behaviors. Therefore, an analytical heat transfer model was written as a system of equations in Fortran code into Aspen Plus® calculation block to simulate the phase change behavior and associated characteristics. The overall simulation model, which was designed specifically for this research work, consists of two main parts that communicate with each other. The first part simulates the AC’s refrigeration loop using the built-in Aspen Plus® components and the second part implements the PCC heat transfer model written within the calculation block of Aspen Plus®. The simulation model was validated by crosschecking the calculated results with actual experimental data from an actual 4 kWh PCC-TES benchtop thermal storage system. Very good agreement was observed between the simulations and laboratory data. Simulated performance of the proposed integration between the AC and the PCC-TES indicated the potential to (1) downsize the compressor by 50%, (2) lower electrical consumption by the compressor by 30%, (3) lower CO2 emissions by 30%, and (4) double the compressor efficiency during off and mid peak hours. The present work is a conceptual design and optimization study and does not account for integration inefficiencies, energy losses, real-world operation complexity, and added capital cost of TES integration with AC systems.

This paper presents a detailed numerical analysis to describe the transient heat transfer in a phase change composite-thermal energy storage (PCC-TES) system exchanging heat with a heat transfer fluid. The “PCC-TES” is precisely composed of 78% low temperature paraffin, namely n-Tetradecane (C14H30) and 22% expanded graphite) and a heat transfer fluid (namely, ethylene glycol). Such detailed numerical approach to precisely describe the heat exchange between this specifically proposed phase change composite thermal energy storage (PCC-TES) and the heat transfer fluid has not been yet addressed in literature. The mathematical modeling of the PCC-TES involves formulating two PDEs that represent conduction within the PCC (phase 1) and advection within the heat transfer fluid (phase 2). The two coupled PDEs were solved with a finite difference method. Numerics were implemented using Fortran. Results were validated using experimental data and demonstrated acceptable agreement and an accurate representation of this specific transient heat transfer problem. The variations between experimental time traces of temperature and numerically calculated data are estimated at approximately (4–9%) and attributed to the heat loss in the actual experiment. Accordingly, the slabs in the actual experiment needed a longer time to reach the temperature of the Ethylene Glycol entering the PCC-TES structure from the inlet at the top. The paper also demonstrated that a lumped-parameter ODE model can perform an incredibly good job of predicting the enthalpy uptake of the PCC precisely matching the PDE results for the enthalpy uptake of the PCC due to the high thermal conductivity of the graphite. The proposed PCC-TES system will be integrated with air conditioning systems to efficiently meet cooling demand and reduce emissions. Previous work by our research group has demonstrated that the [AC + PCC-TES] hybrid design can reduce compressor size by 50%, double the compressor efficiency (COP) during mid/off-peak hours, reduce electricity consumption by 30%, and cut CO2 emissions by 30% – all without compromising overall system performance or building comfort level.

Atmospheric Pressure Photoionization (APPI) in Mass Spectrometry (MS) has been utilized for a lumber of indigo-related compounds and was found to exhibit an excellent response. All structures were ionizad in negative ion mode yielding almost exclusively deprotonated molecules. Their product ion mass spectra were also recorded and showed characteristic losses mainly of small neutrals such as CO, HBr and CONH2. APPI-MS was applied further to the analysis of indigo dyestuffs of historical importance. HPLC with single ion monitoring (SIM) was employed for the separation and detection of the compounds. A simple HPLC gradient that separated the components in less than 10 min was developed. MS/MS spectra of the colouring components were also recorded and compared to that of the referente substances. The composition of Tyrian purple originating from Murex trunculus (Hexaplex trunculus), was by far the most complex, whereas some of the structures were also detected in Purpura haemastoma (Stramonita haemastoma) and Plicopurpura pansa (Plicopurpura patula subs. pansa). Further, a number of synthetic indigo dyes, produced at different times of the 19thcentury by different manufacturers, were analyzed; similar spectra were obtained suggesting that these were highly pure. Overall, the developed analytical procedure was very efficient offering high sensitivity and selectivity. APPI was proved suitable for ionizing the species under investigation producing clear mass spectra with characteristic fragment ions and may be used successfully in the future for the characterization of similar structures in historical art objects.

Objectives: The aim of this study was to assess the value of multislice computed tomography (CT) for the assessment of valvular abnormalities in patients with infective endocarditis (IE) in compari...

Singular perturbation theory is combined with the method of multiple scales to derive an asymptotic solution for the transient, one-dimensional probability density function (PDF) of a FENE dumbbell in a suddenly started uniaxial extensional flow. We consider the dual asymptotic limit of large dimensionless spring length, L = ɛ − 1 , and large dimensionless elongation rate (or Weissenberg number), Γ = γ / ɛ , with these two quantities remaining in a fixed (arbitrary) proportion, γ . The analytical formula for the transient PDF agrees closely with numerics in both (i) the central, approximately Gaussian core, and (ii) a thin boundary layer near the limit of extension [see, e.g., R. Keunings, J. Non-Newtonian Fluid Mech. 68 (1997) 85–100]. Stress buildup and stress–extension curves are well predicted. We also explain the collapse of different dumbbell lengths onto a single stress–extension line, τ = 2 Γ 〈 x 2 〉 , which has been observed numerically in connection with transient stress-birefringence [P.S. Doyle, E.S.G. Shaqfeh, G.H. McKinley, S.H. Spiegelberg, J. Non-Newtonian Fluid Mech. 76 (1998) 79–110]. This result agrees with the large-strain plateau in the transient stress-optic coefficient for large Weissenberg number [R. Sizaire, G. Lielens, I. Jaumain, R. Keunings, V. Legat, J. Non-Newtonian Fluid Mech. 82 (1999) 233–253]. For relaxation of the FENE dumbbell from its fully stretched configuration, a Gaussian approximation of the PDF—whose time-dependent position and width are given by closed analytical formulas—matches the numerical results extremely well. The slope of the advective velocity is interpreted as a negative contribution to the effective diffusion coefficient. The asymptotic theory supports the recently proposed L closure [G. Lielens, P. Halin, I. Jaumain, R. Keunings, V. Legat, J. Non-Newtonian Fluid Mech. 76 (1998) 249–279].

This paper applies the recent L closure [G. Lielens, P. Halin, I. Jaumain, R. Keunings, V. Legat, J. Non-Newtonian Fluid Mech., 76 (1998), 249–279], which was originally developed for FENE dumbbells with fixed friction, to two alternative dumbbell models of polymers in a dilute solution undergoing uniaxial extension: (A) a linear-locked dumbbell with fixed friction and (B) a FENE dumbbell with variable friction. The simplified box-spike representation of the probability density function (PDF) – used for Model B to close conformational averages of nonlinear quantities in terms of a reduced set of state variables (moments of the PDF) – is justified through detailed asymptotic analysis (singular perturbations combined with multiple scales) of the Smoluchowski equation, in the limit of large extensibility parameter at fixed elongation rate. Both dumbbell models A and B are actually more amenable to the L closure than the FENE to which it had previously been applied. The resulting closure relations compare favorably with corresponding integrals of asymptotic or numerical PDF’s (the latter obtained via atomistic SPH simulations of the Smoluchowski equation). Example calculations show the L closure to yield reasonably accurate stress–extension curves, even for a moderate (dimensionless) limit of extension ( L = 4 ).

Background Lung transplantation has become important in treating end-stage lung disease; however, bronchial complications are common. Lack of bronchial arterial circulation, ischemic time, and acute rejection episodes may damage the bronchial wall. In this study, we analyzed factors that may hamper bronchial airway healing, requiring intervention after lung transplantation. Methods We collected data from a consecutive series of 81 transplantations performed between 1993 and 2002 and evaluated recipients for bronchial complications. In 30 single and 51 sequential bilateral lung transplantations, a total of 132 anastomoses were performed. Four patients (3 bilateral and 1 single lung transplant recipients who died within the first 14 post-operative days were excluded from the analysis. Finally, 125 lung grafts remained for statistical analysis of factors influencing bronchial complications. Results Peri-operative mortality was 8.9%. Eleven patients (14.7%) experienced severe bronchial complications in 16 of 125 evaluated bronchial anastomoses (12.8%) and required surgical treatment or bronchoscopic interventional therapy. In a multivariate logistic regression model, severe reperfusion edema (adjusted odds ratio, 8.3; p = 0.002) and rejection episode within the 1st post-operative month (adjusted odds ratio, 4.1; p = 0.036) were associated with bronchial complications. Using the univariate model, we found that factors such as interleukin-2-antibody induction therapy, immunosuppression, or bronchial anastomotic technique had significant influence on bronchial healing, whereas we could not confirm this when using multivariate anasysis. Conclusions Preventing reperfusion edema with optimized lung preservation and with early and aggressive medical treatment or mechanical hemodynamical support (e.g., veno-arterial extra corporal membrane oxygenation are necessary to avoid prolonged ventilation dependence, which may result in bronchial complications. Furthermore, avoiding early rejection episodes promotes uncomplicated bronchial healing.

For sedimenting, immiscible drops at unit viscosity ratio, a cohesive chemical potential is formulated to agree formally with the boundary-integral (BI) equation of Stokes flow. Against conventional wisdom, the resulting 'bulk cohesion' (BC) force field does not give rise to interfacial tension. Nevertheless, particle simulations based upon this concept accurately reproduce complex shape evolutions of trailing drops as calculated with BI. The BC force is easier to compute than volumetric versions of interfacial tension, and the radius of cohesion need not be small. (C) 2004 Elsevier B.V. All rights reserved.

Molecular dynamics simulations examine the effect of pore size, structure and membrane thickness on flux and selectivity in reverse osmosis. Membranes are modeled using layers of barrier molecules tethered harmonically to periodic lattice sites. Permeation occurs within a Knudsen like regime where close confinement in nanopores precludes water–water interactions, leaving water–pore interactions to determine hydraulic resistance. Results show the solvent flux to be rather insensitive to an appropriately defined tortuosity. Ion selectivity seems to correlate primarily with overall hydraulic resistance, irrespective of the number of membrane layers.

For sedimentation of miscible drops through quiescent liquid of the same viscosity, a recent paper [J. Fluid. Mech. 447 (2001) 299] has shown the effectiveness of computer simulations based upon a swarm of point forces in tracking coalescence, mixing and rupture. Robustness of the approach was offset by the slow O(Np2) summations needed to calculate the mutual viscous interactions between all Np particles. Motivated by applications of wavelets to linear operators, this paper develops a conceptually simple scheme for dramatically accelerating the simulations. After lumping the particles together into N local clusters (three-dimensional “pixels”), a Haar discrete wavelet transform (DWT) is used to “compress” the “bitmapped” six-dimensional image of pixel–pixel hydrodynamic interactions. Depending upon the criterion of accuracy, the numerically observed scaling of the operation count seems to be either O(N) or O[N( log N) α ] . The DWT also works without modification for hydrodynamic wall effects, where the kernel is not purely translational and therefore fast convolutions (FFT) cannot be used.

During laboratory experiments Artemia were fed 14 days from nauplius to adult stage with a commercially available, enriched and unenriched, inert, dry baby food (‘Nestum’). Growth, survival, and nutrient content of Artemia were determined, and compared with Artemia fed with the unicellular microalgae Chaetoceros sp. Raising Artemia on Nestum resulted in a high survival rate (Nestum: 72%; Nestum enriched 79%) and after 11 days a growth of 4.93 mm with Nestum and 5.02 mm with enriched Nestum, which was similar to Artemia reared on Chaetoceros. The lipid content of Artemia reared on Nestum was significantly higher and the protein content lower than Artemia reared on Chaetoceros. The carbohydrate and ash content were similar. The results show that rearing Artemia with Nestum is a viable and economical alternative to the laborious production of unicellular algae.

This paper represents a numerical investigation of the hydrodynamics and mass transfer operative in antipolarization dialysis (“APD”), a novel concept for fractionation in which adjacent countercurrent flow streams are (i) separated by a longitudinal solute-selective membrane, and (ii) pass through upstream and downstream “barrier” membranes that reject all solutes. Selectivity of the process—embodied in the sensitivity of steady-state concentration profiles to Peclet number and membrane transport resistance—has previously been analyzed (Nitsche, L. C., 1994, Quart. Appl. Math. , LII , 83–102) using the simplifying idealization of plug flow. Practical considerations of construction require the barrier membranes to be positioned longitudinally instead of transversely, so that the corresponding ultrafiltration flows occur perpendicular to the fully developed, parabolic velocity profiles in the channels. These hydrodynamic end effects are modeled numerically using a least-squares boundary singularity method that explicitly incorporates the analytical structure of discontinuities in the flow field arising at the junctions between porous and impermeable boundaries. Subsequently, the impact of flow nonidealities upon the transport of solute is addressed by applying finite differences to the relevant elliptic convection-diffusion equation for the concentration field. Calculations at large values of the aspect ratio take advantage of the singular asymptotic structure of the problem, whereby only the “inner” behavior at the ends of the flow channel is treated with a fine mesh in the longitudinal coordinate; a smoothly expanded mesh is sufficient for resolving the “outer” behavior in between. The grid is also selectively refined near the singularities in the convective coefficients. At unit Peclet number (based upon width of the flow channels) the resulting selectivity curves are found to be in remarkably close quantitative agreement with those for plug flow, despite major differences in the inner solute concentration profiles—a feature that does not persist at significantly higher Peclet numbers. Drawing an analogy with sedimentation-diffusion processes in rotating cylinders, the underlying mechanism of antipolarization is interpreted in terms of a circulation-flux parameter. In this way we illuminate the apparent robustness of the fractionation scheme with respect to details of the convective field.

Transcatheter valve interventions, hybrid coronary and aortic disease procedures require angiographic intraoperative imaging supporting a heart team approach. Facing limited financial and logistic possibilities of many medical centers, alternative periprocedural imaging strategies should be

Fifty neuroendocrine tumors of the lung (16 carcinoids, two atypical carcinoids/well-differentiated neuroendocrine carcinomas [WDNCs], 13 neuroendocrine carcinomas of intermediate cell type [ICNCs], and 19 neuroendocrine carcinomas of small cell type [SCNs]) were immunohistochemically investigated with antibodies against chromogranins A and B. All carcinoids and WDNCs were positive for both chromogranins A and B, whereas in cases of ICNC and SCNC both markers were only expressed in six and five cases, respectively. One ICNC was only positive for chromogranin A. In cases of SCNC five tumors were exclusively positive for chromogranin A and six were positive only for chromogranin B. Chromogranins are therefore excellent markers for the immunohistochemical demonstration of carcinoids and WDNCs. It may be speculated that expression of chromogranins in cases of ICNC and SCNC represets a higher degree of differentiation in these tumors.

There are 3 clinical types of pulmonary aspergillosis. The allergic and saprophytic forms can be encountered in immunocompetent patients, whereas invasive pulmonary aspergillosis (IPA) is a life-threatening opportunistic infectious complication that develops in the immunocompromised host as a consequence of impaired defense function. IPA represents a major source of morbidity and mortality in the neutropenic patient. The clinical symptoms are sometimes masked, especially in the setting of a malignant neoplastic disorder; however, as a rule, there is productive cough and hemoptysis up to life-threatening bleeding. Standard therapy consists of amphotericin B, itraconazole, or both; however, new antifungal agents, such as voriconazole or caspofungin, might yield superior therapeutic results. Surgical removal of infected lung tissue is considered as a therapy of last resort.