When using liquid chromatography/mass spectrometry (LC/MS) to perform untargeted metabolomics, it is common to detect thousands of features from a biological extract. Although it is impractical to ...collect non-chimeric MS/MS data for each in a single chromatographic run, this is generally unnecessary because most features do not correspond to unique metabolites of biological relevance. Here we show that relatively simple data-processing strategies that can be applied on the fly during acquisition of data with an Orbitrap ID-X, such as blank subtraction and well-established adduct or isotope calculations, decrease the number of features to target for MS/MS analysis by up to an order of magnitude for various types of biological matrices. We demonstrate that annotating these non-biological contaminants and redundancies in real time during data acquisition enables comprehensive MS/MS data to be acquired on each remaining feature at a single collision energy. To ensure that an appropriate collision energy is applied, we introduce a method using a series of hidden ion-trap scans in an Orbitrap ID-X to find an optimal value for each feature that can then be applied in a subsequent high-resolution Orbitrap scan. Data from 100 metabolite standards indicate that this real-time optimization of collision energies leads to more informative MS/MS patterns compared to using a single fixed collision energy alone. As a benchmark to evaluate the overall workflow, we manually annotated unique biological features by independently subjecting E. coli samples to a credentialing analysis. While credentialing led to a more rigorous reduction in feature number, on-the-fly annotation with blank subtraction on an Orbitrap ID-X did not inappropriately discard unique biological metabolites. Taken together, our results reveal that optimal fragmentation data can be obtained in a single LC/MS/MS run for >90% of the unique biological metabolites in a sample when features are annotated during acquisition and collision energies are selected by using parallel mass spectrometry detection.
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•Blank subtraction does not unfaithfully remove credentialed features.•Filtering common redundancies and contaminants reduces the MS/MS burden up to 90%.•Collision energies can be optimized in real time with dual MS detection.•Optimal MS/MS data for >90% of credentialed metabolites can be acquired in one run.
A new approach for simulating the formation of foam in aerated liquid is proposed. Foam is considered as a separate phase which is comprised of a mixture of air and liquid. A computational fluid ...dynamic (CFD) model has been developed for the simulation of creaming and formation of foam in aerated liquid using the proposed approach. The model accounts for the formation of foam due to transformation of both air and liquid into foam and it is destruction due to liquid drainage and bursting of bubbles. The coalescence model of Prince and Blanch (1990. Bubble coalescence and break-up in air-sparged bubble columns. AIChE J. 36, 1485–1499.) was considered for air-liquid dispersion whereas for the foam layer, the bubble coalescence due to film rupture was modeled using the model developed by Tong et al. (2011. Drainage and stability of 2D foams: foam behavior in vertical Hele-Shaw cells. Colloid Surf. A 382, 42–49). A population balance method was used to track the number density of different bubble class and the fixed pivot method was used to discretize the population balance equation. The source term for coalescence in the scalar transport equation was updated using a rectified model of Hagesaether et al. (2002. A model for turbulent binary breakup of dispersed fluid particles. Chem. Eng. Sci. 57, 3251–3267). The results obtained are in reasonable agreement with the predictions of Narsimhan (2010. Analysis of creaming and formation of foam layer in aerated liquid. J. Colloid Interface Sci. 345, 566–572.). The discrepancies were mainly attributed to assumption of uniform size bubble in Narsimhan (2010).
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► A CFD model was developed with new approach for creaming and formation of foam in aerated liquid. ► Population balance model was incorporated to track the number density of individual bubble classes. ► Phase diagram was drawn and different regions were identified and discussed.
In this paper a full scale combustion model incorporating upstream mill ducting of a large tangentially fired boiler with flue gas recirculation was examined numerically. Lagrangian particle tracking ...was used to determine the coal particle paths and the Eddy Dissipation Model for the analysis of the gas phase combustion. Moreover volatiles and gaseous char products, given off by the coal particles were modelled by Arrhenius single phase reactions and a transport equation was solved for each material given off by the particles. Thermal, prompt, fuel and reburn NO
x
models with presumed probability density functions were used to model NO
x
production and the discrete transfer radiation model was used to model radiation heat transfer. Generally, the findings indicated reasonable agreement with observed qualitative and quantitative data of incident heat flux on the walls. The model developed here could be used for a range of applications in furnace design and optimisation of gas emissions of coal fired boiler plants.
The aerodynamic development of fully turbulent isothermal jets issuing from rectangular slot-burners was modelled by obtaining a solution to the Reynolds averaged Navier–Stokes equations. A ...finite-volume method was used with the standard
k–ε, RNG
k–ε and Reynolds stress turbulence models. The slot-burners were based on physical models, which were designed to be representative of typical burner geometries found in tangentially-fired coal boilers. Two cases were investigated, in which jets from three vertically stacked rectangular nozzles discharged at 90° and then 60° to the wall containing the burner. The nozzle angle had little effect on jet centreline velocity decay, with the 60° nozzle showing a marginally higher rate of decay. The jets from the 60° nozzles were found to deviate slightly from their geometric axis slightly due to internal pressure redistribution in the flow at the nozzles. The simulations were validated against the physical models and were found to reproduce the flow field of the jets accurately with the Reynolds stress model producing the best results.
BACKGROUND Lymphangiomas are rare and benign malformations of the lymphatic system. The presentation of intra-abdominal lymphangiomas, especially from within the hepatoduodenal ligament, is rare in ...the adult population. In this report, we examine a lymphangioma within the hepatoduodenal ligament resulting in biliary obstruction. CASE REPORT A 62-year-old man with surgical history of cholecystectomy presented to the hepatobiliary clinic for a peri-hilar cystic lesion identified on surveillance magnetic resonance imaging (MRI). The patient's MRI revealed a 5.5-cm cystic lesion at the peri-hilar region, likely arising from the biliary tree, which had been increasing in size and causing biliary dilatation. The patient underwent an endoscopic ultrasound, showing a 4.3×2.2 cm cystic structure likley arising from the cystic duct stump with internal septation. An endoscopic retrograde cholangiopancreatography (ERCP) was performed and demonstrated no communication between the biliary tree and the cystic lesion. Given the uncertain etiology of the lesion and its obstructive nature, the patient was moved to the operating room for a complete excision. A well-encapsulated cystic lesion was identified between the cystic duct and the common hepatic duct, which did not communicate with the biliary tree. Pathology confirmed the diagnosis of lymphangioma with features of vascular channel proliferation in the background of fibrotic stroma and lymphoid aggregates. The vascular channel proliferation demonstrated positive immunohistochemical staining for D2-40. At 3-year follow-up, there was no evidence of post-resection recurrence. CONCLUSIONS This case represents an acquired lymphangioma occurring as a sequela of cholecystectomy, likely caused by interruption of the lymphatic drainage system secondary to surgical manipulation.
•This paper presents an experimental investigation of the effect of jet velocity ratio.•Experiments for both single and two-phase flow were performed.•Both the primary jet and the lower secondary jet ...deviated from their geometric axes.•In a real furnace a large quantity of fuel will be directed close to the wall.•Such characteristics may contribute to substantial wall fouling.
The power generation industry throughout the world stands to gain significantly from process improvements and optimization which can potentially lead to cleaner production of cost effective electricity. The efficient operation of lignite-based tangentially-fired combustion systems, as commonly used in Victoria, Australia, depends on critical issues such as ignition and combustion of the fuel, which are largely controlled by burner aerodynamics. The geometry of the burner and the ratio of velocities between the primary and secondary jets play an important role in achieving stable combustion, high burnout of fuel, low production of pollutants and control of fouling. Slot-burners are vertically aligned stacks of rectangular nozzles delivering primary fuel and secondary air jets, and are commonly used in tangentially-fired boilers. To obtain a better understanding of the overall combustion process, it is important to understand the aerodynamics of jet development from these burners. This paper reports an experimental investigation into the aerodynamics of a recessed rectangular slot-burner of the type used in the Yallourn stage-2 tangentially-fired furnace. The 1:15 scale model burner consisted of a central (primary) rectangular fuel nozzle with two secondary rectangular air jets positioned above and below it. The burner jets were at an angle of 60° to the wall and were diffused and mixed in a recess before entering into the measurement vessel. A cross-flow jet was attached to the wall of the vessel to simulate the recirculation similar to tangentially-fired furnaces. Experiments for both single and two-phase flow were performed. For single-phase flow, the air flow was seeded with a fine mist of sugar particles (mean diameter 1μm) introduced into the primary, secondary and cross-flow ducts. For two-phase flow, solid glass spheres (mean diameter 66μm, density 2450kg/m3) were used as the representative of the coal particles and were introduced only at the centre of the primary duct from a bubbling fluidized bed. Experiments were conducted using a primary to cross-flow jet velocity ratio (φ) of 1.0 and secondary to primary jet velocity ratios (ϕ) of 1.0 and 3.0 as found in real furnaces. Laser Doppler Anemometry (LDA) was used to measure mean and turbulent velocity components in the near field and downstream regions of the jets. The flow pattern inside the recess was very complex and greatly influenced the flow where it entered the measurement vessel. For single-phase flow and ϕ=1.0, the jets diverged completely from the geometric axis of the burner and attached to the wall. The degree of deflection of the lower secondary jet was slightly more than the primary jet. For ϕ=3.0, after exiting from the nozzle, the primary jet diffused outwards and mixed with the higher momentum secondary jets in the recess and came out with the secondary jets. For two-phase flow and ϕ=1.0, in the mixing region between the primary and cross-flow jet, the gas-phase velocities were higher than the particle-phase. Further downstream the peak velocities of the particle-phase slightly deviated and occurred farther from the wall. For ϕ=3.0, downstream of the nozzle there was a tendency of separation for the gas-phase near the wall while the particle-phase was attached to the wall.
This is a pioneering paper that deals with the semi-steady-state liquid film thickness on a rotating drum partially submerged in liquid using CFD. The CFD predictions have been compared with both ...experimental results and analytical solutions. The liquid film thickness and the film rising on a circular curved wall were monitored for various rpm of the rotating drum. The 2D simulations were performed neglecting the end effects (assuming the rotating drum is very long). As the rotating drum speed was increased, the film thickness was found to increase at the film rising side and at the minimum film thickness point (top of the rotating drum). There was never been a steady-state condition reached, the opposite was expected as a wiper is used in the CFD calculation (same as the experimental investigation). The liquid that leaves the domain by the wiper (as outflow boundary condition) is forced to enter to the domain from far end to keep the level of the free surface constant.
Abstract Propionic acidemia manifesting with hyperglycemia is rare. Few cases have been reported mainly of the neonatal-onset form associated with high mortality. We report a 9-month-old Palestinian ...boy who manifested with coma, severe hyperglycemia and ketoacidosis mimicking diabetic ketoacidosis. Family history of unexplained infant deaths was helpful in reaching the correct diagnosis. In response to therapy, the patient regained consciousness without neurologic deficits and had normal examination. This is, to our knowledge, the first case report of late-onset propionic acidemia that had this presentation and survived.
A rare and lethal vascular condition is the communication of the thoracic aorta and tracheobronchial tree. Typically, the development occurs after open or endovascular aortic repair that has been ...complicated by infection and usually presents with hemoptysis as the heralding event, which can lead to massive hemorrhage. Computed tomography angiography remains the diagnostic imaging modality of choice. Medical management will be futile, with the need for expedited operative intervention via open, endovascular, or hybrid open and endovascular repair.
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