Modeling of Neuronal Growth In Vitro: Comparison of Simulation Tools NETMORPH and CX3D

We simulate the growth of neuronal networks using the two recently published tools, NETMORPH and CX3D. The goals of the work are (1) to examine and compare the simulation tools, (2) to construct a model of growth of neocortical cultures, and (3) to characterize the changes in network connectivity during growth, using standard graph theoretic methods. Parameters for the neocortical culture are chosen after consulting both the experimental and the computational work presented in the literature. The first (three) weeks in culture are known to be a time of development of extensive dendritic and axonal arbors and establishment of synaptic connections between the neurons. We simulate the growth of networks from day 1 to day 21. It is shown that for the properly selected parameters, the simulators can reproduce the experimentally obtained connectivity. The selected graph theoretic methods can capture the structural changes during growth.Peer reviewe

Orientational order parameters of a de Vries–type ferroelectric liquid crystal obtained by polarized Raman spectroscopy and x-ray diffraction

The orientational order parameters 〈P2〉 and 〈P4〉 of the ferroelectric, de Vries–type liquid crystal 9HL have been determined in the SmA* and SmC* phases by means of polarized Raman spectroscopy, and in the SmA* phase using x-ray diffraction. Quantum density functional theory predicts Raman spectra for 9HL that are in good agreement with the observations and indicates that the strong Raman band probed in the experiment corresponds to the uniaxial, coupled vibration of the three phenyl rings along the molecular long axis. The magnitudes of the orientational order parameters obtained in the Raman and x-ray experiments differ dramatically from each other, a discrepancy that is resolved by considering that the two techniques probe the orientational distributions of different molecular axes. We have developed a systematic procedure in which we calculate the angle between these axes and rescale the orientational order parameters obtained from x-ray scattering with results that are then in good agreement with the Raman data. At least in the case of 9HL, the results obtained by both techniques support a “sugar loaf” orientational distribution in the SmA* phase with no qualitative difference to conventional smectics A. The role of individual molecular fragments in promoting de Vries–type behavior is considered

Measuring individual overpotentials in an operating solid-oxide electrochemical cell

We use photo-electrons as a non-contact probe to measure local electrical potentials in a solid-oxide electrochemical cell. We characterize the cell in operando at near-ambient pressure using spatially-resolved X-ray photoemission spectroscopy. The overpotentials at the interfaces between the Ni and Pt electrodes and the yttria-stabilized zirconia (YSZ) electrolyte are directly measured. The method is validated using electrochemical impedance spectroscopy. Using the overpotentials, which characterize the cell's inefficiencies, we compare without ambiguity the electro-catalytic efficiencies of Ni and Pt, finding that on Ni H_2O splitting proceeds more rapidly than H2 oxidation, while on Pt, H2 oxidation proceeds more rapidly than H2O splitting.Comment: corrected; Phys. Chem. Chem. Phys., 201

Overview of NASA Technology Development for In-Situ Resource Utilization (ISRU)

In-Situ Resource Utilization (ISRU) encompasses a broad range of systems that enable the production and use of extraterrestrial resources in support of future exploration missions. It has the potential to greatly reduce the dependency on resources transported from Earth (e.g., propellants, life support consumables), thereby significantly improving the ability to conduct future missions. Recognizing the critical importance of ISRU for the future, NASA is currently conducting technology development projects in two of its four mission directorates. The Advanced Exploration Systems Division in the Agency's Human Exploration and Operations Mission Directorate has initiated a new project for ISRU Technology focused on component, subsystem, and system maturation in the areas of water volatiles resource acquisition, and water volatiles and atmospheric processing into propellants and other consumable products. The Space Technology Mission Directorate is supporting development of ISRU component technologies in the areas of Mars atmosphere acquisition, including dust management, and oxygen production from Mars atmosphere for propellant and life support consumables. Together, these two coordinated projects are working towards a common goal of demonstrating ISRU technology and systems in preparation for future flight applications

Effects of an interactive CD-program on 6 months readmission rate in patients with heart failure – a randomised, controlled trial [NCT00311194]

BACKGROUND: Disease-management programmes including patient education have promoted improvement in outcome for patients with heart failure. However, there is sparse evidence concerning which component is essential for success, and very little is known regarding the validity of methods or material used for the education. METHODS: Effects of standard information to heart failure patients given prior to discharge from hospital were compared with additional education by an interactive program on all-cause readmission or death within 6 months. As a secondary endpoint, patients' general knowledge of heart failure and its treatment was tested after 2 months. RESULTS: Two hundred and thirty patients were randomised to standard information (S) or additional CD-ROM education (E). In (S) 52 % reached the endpoint vs. 49 % in (E). This difference was not significant. Of those who completed the questionnaire (37 %), patients in (E) achieved better knowledge and a marginally better outcome. CONCLUSION: The lack of effect on the readmission rate could be due to an insufficient sample size but might also indicate that in pharmacologically well-treated patients there is little room for altering the course of the condition. As there was some indication that patients who knew more about their condition might fare better, the place for intensive education and support of heart failure patients has yet to be determined

Study of mass and momentum transfer in diesel sprays base on X-ray mass distribution measurements and on a theoretical derivation

[EN] In this paper, a research aimed at quantifying mass and momentum transfer in the near-nozzle field of diesel sprays injected into stagnant ambient air is reported. The study combines X-ray measurements for two different nozzles and axial positions, which provide mass distributions in the spray, with a theoretical model based on momentum flux conservation, which was previously validated. This investigation has allowed the validation of Gaussian profiles for local fuel concentration and velocity near the nozzle exit, as well as the determination of Schmidt number at realistic diesel spray conditions. This information could be very useful for those who are interested in spray modeling, especially at high-pressure injection conditions. © 2010 Springer-Verlag.This work was partly sponsored by "Vicerrectorado de Investigacion, Desarrollo e Innovacion'' of the "Universidad Politecnica de Valencia'' in the frame of the project "Estudio del flujo en el interior de toberas de inyeccion Diesel'', reference no. 3150 and by "Generalitat Valenciana'' in the frame of the project with the same title and reference GV/2009/031. This support is gratefully acknowledged by the authors.Desantes, J.; Salvador Rubio, FJ.; López, JJ.; De La Morena, J. (2011). Study of mass and momentum transfer in diesel sprays base on X-ray mass distribution measurements and on a theoretical derivation. Experiments in Fluids. 50(2):233-246. https://doi.org/10.1007/s00348-010-0919-8S233246502Abramovich GN (1963) The theory of turbulent jets. MIT Press, Cambridge, MAAdler D, Lyn WT (1969) The evaporation and mixing of a liquid fuel spray in a Diesel air swirl. Proc Instn Mech Eng 184:171–180Coghe A, Cossali GE (1994) Phase Doppler characterisation of a Diesel spray injected into a high density gas under vaporisation regimes. In: 7th international symposium on application of laser techniques to fluid mechanics, LisbonCorreas D (1998) Theoretical and experimental study of isothermal Diesel free sprays (in Spanish). PhD Thesis, Universidad Politécnica de ValenciaCossali GE (2001) An integral model for gas entrainment into full cone sprays. J Fluid Mech 439:353–366Dent JC (1971) A basis for the comparison of various experimental methods for studying spray penetration. SAE Paper 710571Desantes JM, Payri R, Salvador FJ, Gil A (2006a) Deduction and validation of a theoretical model for a free diesel Spray. Fuel 85:910–917Desantes JM, Arrègle J, López JJ, Cronhjort A (2006b) Scaling laws for free turbulent gas jets and Diesel-like sprays. Atomization Spray 16:443–473Desantes JM, Payri R, García JM, Salvador FJ (2007) A contribution to the understanding of isothermal diesel spray dynamics. Fuel 86:1093–1101Dumouchel C (2008) On the experimental investigation on primary atomization of liquid streams. Exp Fluids 45:371–422Heimgärtner C, Leipertz A (2000) of the primary spray break-up close to the nozzle of a common-rail high pressure diesel injection system. SAE Paper 2000-01-1799Hinze JO (1975) Turbulence. McGraw Hill, New YorkHiroyasu H, Arai M (1990) Structures of fuel sprays in diesel engines. SAE Paper 900475Jawad B, Gulari E, Henein NA (1992) Characteristics of intermittent fuel sprays. Combust Flame 88:384–396Lefèbvre AH (1989) Atomization and sprays. Hemisphere, New YorkLeick P, Riedel T, Bittlinger G, Powell CF, Kastengren AL, Wang J (2007) X-Ray measurements of the mass distribution in the dense primary break-up region of the spray from a standard multi-hole common-rail diesel injection system. In: Proc 21st ILASS (Europe)Linne M, Paciaroni M, Hall T, Parker T (2006) Ballistic imaging of the near field in a diesel spray. Exp Fluids 40:836–846Naber J, Siebers DL (1996) Effects of gas density and vaporisation on penetration and dispersion of diesel sprays. SAE Paper 960034Payri F, Bermúdez V, Payri R, Salvador FJ (2004) The influence of cavitation on the internal flow and the Spray characteristics in diesel injection nozzles. Fuel 83:419–431Payri R, García JM, Salvador FJ, Gimeno J (2005) Using spray momentum flux measurements to understand the influence of diesel nozzle geometry on spray characteristics. Fuel 84:551–561Payri R, Tormos B, Salvador FJ, Araneo L (2008) Spray droplet velocity characterization for convergent nozzles with three different diameters. Fuel 87:3176–3182Post S, Iyer V, Abraham J (2000) A study of near-field entrainment in gas jets and sprays under diesel conditions. ASME J Fluids Eng 122:385–395Prasad CMV, Kar S (1976) An investigation on the diffusion of momentum and mass of fuel in a diesel fuel spray. ASME J Eng Power 76-DGP-1:1–11Rajaratnam N (1976) Turbulent jets. Elsevier, AmsterdamRamirez AI, Som S, Aggarwal SK, Kastengren AL, El-Hannouny EM, Longman DE, Powell CF (2009) Quantitative X-ray measurements of high-pressure fuel sprays from a production heavy duty diesel injector. Exp Fluids 47:119–134Reitz RD, Bracco FV (1982) Mechanism of atomisation of a liquid jet. Phys Fluids 25(10):1730–1742Ricou FP, Spalding DB (1961) Measurements of entrainment by axisymmetrical turbulent jets. J Fluid Mech 11:21–32Rife J, Heywood JB (1974) Photographic and performance studies of diesel combustion with a rapid compression machine. SAE Paper 740948Roisman IV, Tropea C (2001) Flux measurements in sprays using phase doppler techniques. Atomization Spray 11:667–699Roisman IV, Araneo L, Tropea C (2007) Effect of ambient pressure on penetration of a diesel spray. Int J Multiphase Flow 33(8):904–920Saliba R, Baz I, Champoussin JC, Lance M, Marié JL (2004) Cavitation effect on the near nozzle spray development in high-pressure diesel injection. In: Proc 19th ILASS (Europe)Schlichting H (1978) Boundary layer theory. McGraw Hill, New YorkSinnamon JF, Lancaster DR, Stiener JC (1980) An experimental and analytical study of engine fuel spray trajectories. SAE Paper 800135Sou A, Hosokawa S, Tomiyama A (2007) Effects of cavitation in a nozzle on liquid jet atomization. Int J Heat Mass Tran 50(17–18):3575–3582Spalding DB (1979) Combustion and mass transfer. Pergamon Press, New YorkSubramaniam S (2001) Statistical modelling of a spray as using the droplet distribution function. Phys Fluids 13(3):624–642Tanner FX, Feigl A, Ciatti SA, Powell CF, Cheong S-K, Liu J, Wang J (2006) Structure of high-velocity dense sprays in the near-nozzle region. Atomization Spray 16:579–597Way RJB (1977) Investigation of interaction between swirl and jets in direct injection diesel engines using a water model. SAE Paper 770412Wu KJ, Santavicca DA, Bracco FV (1984) LDV measurements of drop velocity in diesel-type sprays. AAIA J 22(9):1263–1270Wu KJ, Reitz RD, Bracco FV (1986) Measurements of drop size at the spray edge near the nozzle in atomising liquid jets. Phys Fluids 29(4):941–951Yue Y, Powell CF, Poola R, Wang J, Schaller JK (2001) Quantitative measurements of diesel fuel spray characteristics in the near-nozzle region using X-ray absorption. Atomization Spray 11(4):471–49

Multiphase phenomena in Diesel fuel injection systems

Fuel Injection Equipment (FIE) are an integral component of modern Internal Combustion Engines (ICE), since they play a crucial role in the fuel atomization process and in the formation of a fuel/air combustible mixture, consequently affecting efficiency and pollutant formation. Advancements and improvements of FIE systems are determined by the complexity of the physical mechanisms taking place; the spatial scales are in the order of millimetres, flow may become locally highly supersonic, leading to very small temporal scales of microseconds or less. The operation of these devices is highly unsteady, involving moving geometries such as needle valves. Additionally, extreme pressure changes imply that many assumptions of traditional fluid mechanics, such as incompressibility, are no longer valid. Furthermore, the description of the fuel properties becomes an issue, since fuel databases are scarce or limited to pure components, whereas actual fuels are commonly hydrocarbon mixtures. Last but not least, complicated phenomena such as phase change or transition from subcritical to transcritical/supercritical state of matter further pose complications in the understanding of the operation of these devices

Influence of intense multidisciplinary follow-up and orlistat on weight reduction in a primary care setting

BACKGROUND: Obesity is the most common health problem in developed countries. Recently, several physicians' organizations have issued recommendations for treating obesity to family physicians, including instructions in nutrition, physical activity and medications. The aim of this study was to examine if effective weight-reducing treatment can be given by a family physician. It compares regular treatment with intensive treatment that include close follow-up and orlistat treatment. METHODS: The study was conducted in three primary care clinics. 225 patients were divided into three groups according to their choice. Group A received a personal diet with fortnightly meetings with the family physician and dietitian and orlistat treatment. Group B received a general diet, monthly meetings with the family physician only and orlistat treatment. Group C received a personal diet, monthly meetings with the dietitian only and no drug treatment. The primary endpoint was reduction of at least 5% of the initial weight during the study period. RESULTS: A greater percentage of patients in group A achieved their weight reduction goals than in other groups (51%, 13% and 9% in groups A, B and C, respectively, p < 0.001). There was a significant reduction in triglycerides in all groups, a significant reduction of low density lipids (LDL) in groups A and B and no significant difference in high density lipids (HDL) in any group. CONCLUSIONS: Significant weight reduction was obtained in a family physician setting. Further research is needed to evaluate if, by providing the family physician with the proper tools, similar success can be achieved in more clinics