4,140 research outputs found

    The Suppressor of AAC2 Lethality SAL1 Modulates Sensitivity of Heterologously Expressed Artemia ADP/ATP Carrier to Bongkrekate in Yeast

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    The ADP/ATP carrier protein (AAC) expressed in Artemia franciscana is refractory to bongkrekate. We generated two strains of Saccharomyces cerevisiae where AAC1 and AAC3 were inactivated and the AAC2 isoform was replaced with Artemia AAC containing a hemagglutinin tag (ArAAC-HA). In one of the strains the suppressor of ΔAAC2 lethality, SAL1, was also inactivated but a plasmid coding for yeast AAC2 was included, because the ArAACΔsal1Δ strain was lethal. In both strains ArAAC-HA was expressed and correctly localized to the mitochondria. Peptide sequencing of ArAAC expressed in Artemia and that expressed in the modified yeasts revealed identical amino acid sequences. The isolated mitochondria from both modified strains developed 85% of the membrane potential attained by mitochondria of control strains, and addition of ADP yielded bongkrekate-sensitive depolarizations implying acquired sensitivity of ArAAC-mediated adenine nucleotide exchange to this poison, independent from SAL1. However, growth of ArAAC-expressing yeasts in glycerol-containing media was arrested by bongkrekate only in the presence of SAL1. We conclude that the mitochondrial environment of yeasts relying on respiratory growth conferred sensitivity of ArAAC to bongkrekate in a SAL1-dependent manner. © 2013 Wysocka-Kapcinska et al

    Modelling and Validation of a Gas-Solid Fluidized Bed using Advanced Measurement Techniques

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    With a Euler-two-phase (E2P) approach, through computational fluid dynamics (CFD) techniques, a mathematical model for the prediction of the local hydrodynamic behavior of a gas-solid fluidized bed was implemented. Simulations are conducted for a fluidized bed of 0.14 m internal diameter packed with Gerdart B glass beads particles, with an average diameter of 365 μm, at dimensionless inlet velocities ranging from (Formula presented.). The implemented model considers the multiphase and multiscale interactions through the inclusion of three sub-models, which allows the model to have a broad range of applicability. Predictions were compared against experimental measurements reported on previous contributions for validation purposes. The experimental study was conducted by implementing advanced measurement techniques, such as a differential pressure transducer, and an optical fibre probe for simultaneous measurement of solids holdup and velocity, developed at the Multiphase Flow and Reactors Engineering and Applications Laboratory (mFReal). Local radial solids holdup, solids velocity, and pressure drop profiles were experimentally determined. Results show that the implemented model possesses a high predictive quality, predicting pressure drops with an average absolute relative error (AARE) between 8.6%–11.3%; solids holdup with a root mean squared deviation (RMSD) under 5%; and solids velocity with a RMSD under 22%

    Random Trilobe Packing using Rigid Body Approach and Local Gas-Liquid Hydrodynamics Simulation through CFD with Experimental Validation

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    It is quite difficult to measure the local information of the gas/liquid flow inside random packed extrudate catalyst beds in a large scale. Obtaining the local information through computational fluid dynamic (CFD) simulations in such system is also difficult due to the complexity of random particle packing and two-phase flow simulation. An efficient packing scheme was implemented to randomly pack 2917 trilobe particles (10 cm in height) in a 2-inch column to represent the trickle bed reactor (TBR) based on the rigid body approach. The generated geometry was used to define the computational domain for the two-phase hydrodynamics simulation based on the volume of fluids (VOF) approach. This hydrodynamics modelling study is paired with an experimental study using our in-house developed advanced measurement techniques based on optical fiber probes, which allowed to determine local liquid velocity and saturation profiles. The experimental measurements were used for local validation of the implemented model

    Mathematical Modeling and Pointwise Validation of a Spouted Bed using an Enhanced Bed Elasticity Approach

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    With a Euler-Euler (E2P) approach, a mathematical model for predicting the pointwise hydrodynamic behavior of a spouted bed was implemented though computational fluid dynamics (CFD) techniques. The model considered a bed elasticity approach in order to reduce the number of required sub-models to provide closure for the solids stress strain-tensor. However, no modulus of elasticity sub-model for a bed elasticity approach has been developed for spouted beds, and thus, large deviations in the predictions are obtained with common sub-models reported in literature. To overcome such a limitation, a new modulus of elasticity based on a sensitivity analysis was developed and implemented on the E2P model. The model predictions were locally validated against experimental measurements obtained in previous studies. The experimental studies were conducted using our in-house developed advanced γ-ray computed tomography (CT) technique, which allows to obtain the cross-sectional time-averaged solids holdup distribution. When comparing the model predictions against the experimental measurements, a high predictive quality for the radial solids holdup distribution in the spout and annulus regions is observed. The model predicts most of the experimental measurements for different particle diameters, different static bed heights, and different inlet velocities with deviations under 15%, with average absolute relative errors (AARE) between 5.75% and 7.26%, and mean squared deviations (MSD) between 0.11% and 0.24%

    New Dual Modality Technique Of Gamma-ray Densitometry (GRD) And Optical Fiber Probe (OFP) To Investigate Line-averaged Diameter Profiles Of Gas, Liquid, And Solid Holdups Along The Height Of A Slurry Bubble Column

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    A new hybrid measurement technique was developed and employed to study line-averaged three-phase holdup distribution in a Slurry Bubble Column Reactor (SBCR) using gamma-ray densitometry (GRD) and point optical fiber probe (OFP) techniques. The OFP technique was used to measure the local gas holdup at 45 nodes in the cross-section area of the SBCR at three different axial levels. Thus, the GRD technique measured the spectrum of the SBCR for two different orientations simultaneously with the OFP technique at the same operating conditions to determine the solid holdup distribution radially and axially. The line-averaged solid holdup for 25% solids loading on the higher measurement level at the column\u27s center decreased compared to the lower level by 45.7%, 43.6%, and 41.7% using superficial gas velocities 0.2, 0.3, and 0.4 m/s, respectively. These results are highly remarkable as it often assumed that the solids exhibit a uniform distribution inside the slurry phase

    Development of a Deep Neural Network and Empirical Model for Predicting Local Gas Holdup Profiles in Bubble Columns

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    Estimating local gas holdup profiles in bubble columns is key for their performance evaluation and optimization, as well as for design and scale-up tasks. Up to the current day, there are important limitations in the accuracy and range of applicability of the available models in literature. Two alternatives for the prediction of such local fields can be found in the application of empirical models and the development of deep neural networks (DNN). The main drawback preventing the application of these techniques in previous years was the availability of a large enough databank of local gas holdup experimental measurements. Advances over the last decades in measurement techniques have resulted enough data reported in literature to gather a significative databank for these models\u27 development. A databank containing 1252 experimental points was gathered and used for the development of a quadratic model and a DNN with the rectified linear unit (ReLU) algorithm as the activation function and the adaptive moment estimation (ADAM) algorithm as the optimizer function. The quadratic model and the DNN allowed a highly accurate prediction of the local gas holdup profiles, exhibiting a MSE of 0.0013 and 0.0010, respectively, and an (Formula presented.) and (Formula presented.) for the quadratic model and the DNN, respectively. Furthermore, these developed models allowed for the estimation of the single and multi-feature effects of the operation conditions, geometrical characteristics, and physical properties of the fluids, over the local gas holdup profiles. The two developed models exhibited an enhanced predictive quality when compared with other models available in literature

    Using Argumentation Logic for Firewall Policy Specification and Analysis

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    Firewalls are important perimeter security mechanisms that imple-ment an organisation's network security requirements and can be notoriously difficult to configure correctly. Given their widespread use, it is crucial that network administrators have tools to translate their security requirements into firewall configuration rules and ensure that these rules are consistent with each other. In this paper we propose an approach to firewall policy specification and analysis that uses a formal framework for argumentation based preference reasoning. By allowing administrators to define network abstractions (e.g. subnets, protocols etc) security requirements can be specified in a declarative manner using high-level terms. Also it is possible to specify preferences to express the importance of one requirement over another. The use of a formal framework means that the security requirements defined can be automatically analysed for inconsistencies and firewall configurations can be automatically generated. We demonstrate that the technique allows any inconsistency property, including those identified in previous research, to be specified and automatically checked and the use of an argumentation reasoning framework provides administrators with information regarding the causes of the inconsistency

    Economic removal of chlorophenol from wastewater using multi-stage spiral-wound reverse osmosis process: simulation and optimisation

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    YesThe successful use of Reverse Osmosis (RO) process has increased significantly in water desalination, water treatment and food processing applications. In this work, the economic feasibility of a multi-stage RO process including both retentate and permeate reprocessing for the removal of chlorophenol from wastewater is explored using simulation and optimisation studies. Firstly, a mathematical model of the process is developed based on the solution diffusion model, which was validated using experimental chlorophenol removal from the literature, is combined with several appropriate cost functions to form a full model package. Secondly, for a better understanding of the interactions between the different parameters on the economic performance of the process, a detailed process simulation is carried out. Finally, a multi-objective optimisation framework based on Non-Linear Programming (NLP) problem is developed for minimising the product unit cost, the total annualised cost, the specific energy consumption together with optimising the feed pressure and feed flow rate for an acceptable level of chlorophenol rejection and total water recovery rate. The results clearly show that the removal of chlorophenol can reach 98.8% at a cost of approximately 0.21 $/m³

    Global surveillance of cancer survival 1995-2009: analysis of individual data for 25,676,887 patients from 279 population-based registries in 67 countries (CONCORD-2)

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    BACKGROUND: Worldwide data for cancer survival are scarce. We aimed to initiate worldwide surveillance of cancer survival by central analysis of population-based registry data, as a metric of the effectiveness of health systems, and to inform global policy on cancer control. METHODS: Individual tumour records were submitted by 279 population-based cancer registries in 67 countries for 25·7 million adults (age 15-99 years) and 75,000 children (age 0-14 years) diagnosed with cancer during 1995-2009 and followed up to Dec 31, 2009, or later. We looked at cancers of the stomach, colon, rectum, liver, lung, breast (women), cervix, ovary, and prostate in adults, and adult and childhood leukaemia. Standardised quality control procedures were applied; errors were corrected by the registry concerned. We estimated 5-year net survival, adjusted for background mortality in every country or region by age (single year), sex, and calendar year, and by race or ethnic origin in some countries. Estimates were age-standardised with the International Cancer Survival Standard weights. FINDINGS: 5-year survival from colon, rectal, and breast cancers has increased steadily in most developed countries. For patients diagnosed during 2005-09, survival for colon and rectal cancer reached 60% or more in 22 countries around the world; for breast cancer, 5-year survival rose to 85% or higher in 17 countries worldwide. Liver and lung cancer remain lethal in all nations: for both cancers, 5-year survival is below 20% everywhere in Europe, in the range 15-19% in North America, and as low as 7-9% in Mongolia and Thailand. Striking rises in 5-year survival from prostate cancer have occurred in many countries: survival rose by 10-20% between 1995-99 and 2005-09 in 22 countries in South America, Asia, and Europe, but survival still varies widely around the world, from less than 60% in Bulgaria and Thailand to 95% or more in Brazil, Puerto Rico, and the USA. For cervical cancer, national estimates of 5-year survival range from less than 50% to more than 70%; regional variations are much wider, and improvements between 1995-99 and 2005-09 have generally been slight. For women diagnosed with ovarian cancer in 2005-09, 5-year survival was 40% or higher only in Ecuador, the USA, and 17 countries in Asia and Europe. 5-year survival for stomach cancer in 2005-09 was high (54-58%) in Japan and South Korea, compared with less than 40% in other countries. By contrast, 5-year survival from adult leukaemia in Japan and South Korea (18-23%) is lower than in most other countries. 5-year survival from childhood acute lymphoblastic leukaemia is less than 60% in several countries, but as high as 90% in Canada and four European countries, which suggests major deficiencies in the management of a largely curable disease. INTERPRETATION: International comparison of survival trends reveals very wide differences that are likely to be attributable to differences in access to early diagnosis and optimum treatment. Continuous worldwide surveillance of cancer survival should become an indispensable source of information for cancer patients and researchers and a stimulus for politicians to improve health policy and health-care systems

    Search for massive resonances decaying in to WW,WZ or ZZ bosons in proton-proton collisions at root s=13 TeV

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