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https://www.readbyqxmd.com/read/29452928/comprehensive-on-line-two-dimensional-liquid-chromatography-%C3%A3-supercritical-fluid-chromatography-with-trapping-column-assisted-modulation-for-depolymerised-lignin-analysis
#1
Mingzhe Sun, Margareta Sandahl, Charlotta Turner
Lignin depolymerisation produces a large variety of low molecular weight phenolic compounds that can be upgraded to value-added chemicals. Detailed analysis of these complex depolymerisation mixtures is, however, hampered by the lack of resolving power of traditional analysis techniques. In this study, a novel online comprehensive two-dimensional reversed-phase liquid chromatography (RPLC) × supercritical fluid chromatography (SFC) method with trapping column interface was developed for the separation of phenolic compounds in depolymerised lignin samples...
February 6, 2018: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29437172/closed-loop-feedback-control-for-microfluidic-systems-through-automated-capacitive-fluid-height-sensing
#2
L R Soenksen, T Kassis, M Noh, L G Griffith, D L Trumper
Precise fluid height sensing in open-channel microfluidics has long been a desirable feature for a wide range of applications. However, performing accurate measurements of the fluid level in small-scale reservoirs (<1 mL) has proven to be an elusive goal, especially if direct fluid-sensor contact needs to be avoided. In particular, gravity-driven systems used in several microfluidic applications to establish pressure gradients and impose flow remain open-loop and largely unmonitored due to these sensing limitations...
February 13, 2018: Lab on a Chip
https://www.readbyqxmd.com/read/29405616/flow-volume-loops-measured-with-electrical-impedance-tomography-in-pediatric-patients-with-asthma
#3
Chuong Ngo, Falk Dippel, Klaus Tenbrock, Steffen Leonhardt, Sylvia Lehmann
BACKGROUND: Electrical impedance tomography (EIT) provides information on global and regional ventilation during tidal breathing and mechanical ventilation. During forced expiration maneuvers, the linearity of EIT and spirometric data has been documented in healthy persons. The present study investigates the potential diagnostic use of EIT in pediatric patients with asthma. METHODS: EIT and spirometry were performed in 58 children with asthma (average age ± SD: 11...
February 6, 2018: Pediatric Pulmonology
https://www.readbyqxmd.com/read/29394944/windkessel-model-of-hemodynamic-state-supported-by-a-pulsatile-ventricular-assist-device-in-premature-ventricle-contraction
#4
Keun Her, Joon Yeong Kim, Ki Moo Lim, Seong Wook Choi
BACKGROUND: Counter-pulsation control (CPC) by ventricular assist devices (VADs) is believed to reduce cardiac load and increase coronary perfusion. However, patients with VADs have a higher risk of arrhythmia, which may cause the CPC to fail. Consequently, CPC has not been applied by VADs in clinical practice. The phase-locked loop (PLL) algorithm for CPC is readily implemented in VADs; however, it requires a normal, consistent heartbeat for adequate performance. When an arrhythmia occurs, the algorithm maintains a constant pumping rate despite the unstable heartbeat...
February 2, 2018: Biomedical Engineering Online
https://www.readbyqxmd.com/read/29365118/initial-in-vitro-testing-of-a-paediatric-continuous-flow-total-artificial-heart
#5
Kiyotaka Fukamachi, Jamshid H Karimov, David J Horvath, Gengo Sunagawa, Nicole A Byram, Barry D Kuban, Nader Moazami
OBJECTIVES: Mechanical circulatory support has become standard therapy for adult patients with end-stage heart failure; however, in paediatric patients with congenital heart disease, the options for chronic mechanical circulatory support are limited to paracorporeal devices or off-label use of devices intended for implantation in adults. Congenital heart disease and cardiomyopathy often involve both the left and right ventricles; in such cases, heart transplantation, a biventricular assist device or a total artificial heart is needed to adequately sustain both pulmonary and systemic circulations...
January 19, 2018: Interactive Cardiovascular and Thoracic Surgery
https://www.readbyqxmd.com/read/29331222/on-tubing-fluorescence-measurements-of-the-band-broadening-of-contemporary-injectors-in-ultra-high-performance-liquid-chromatography
#6
Ken Broeckhoven, Kim Vanderlinden, Davy Guillarme, Gert Desmet
We report on a detailed study of the injection contribution to band broadening in contemporary UHPLC-instruments, using either flow-through needle or fixed loop injection (full loop). Using on-tubing fluorescence measurements at the outlet of the injector valve, very localized and undisturbed measurements were obtained. Varying both the flow rate and the injected volume allowed to split the injection variance (σV2,inj) in a volumetric component (related to the amount injected) and a hydrodynamic component (related to the flow rate)...
December 15, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29330837/computer-simulated-modeling-of-healthy-and-diseased-right-ventricular-and-pulmonary-circulation
#7
Jody Chou, Joseph B Rinehart
We have previously developed a simulated cardiovascular physiology model for in-silico testing and validation of novel closed-loop controllers. To date, a detailed model of the right heart and pulmonary circulation was not needed, as previous controllers were not intended for use in patients with cardiac or pulmonary pathology. With new development of controllers for vasopressors, and looking forward, for combined vasopressor-fluid controllers, modeling of right-sided and pulmonary pathology is now relevant to further in-silico validation, so we aimed to expand our existing simulation platform to include these elements...
January 12, 2018: Journal of Clinical Monitoring and Computing
https://www.readbyqxmd.com/read/29203113/improved-separation-by-at-column-dilution-in-preparative-hydrophilic-interaction-chromatography
#8
Geoffrey Jaffuel, Laura Chappuis, Davy Guillarme, Ted C J Turlings, Gaétan Glauser
We evaluated at-column dilution (ACD) as a possible approach to reduce peak distortion caused by the injection of strong solvents in preparative hydrophilic interaction chromatography (HILIC). Three model compounds, namely uridine, cytidine and guanosine were selected and injected either in conventional or ACD conditions, using various proportions of water and acetonitrile in the sample diluent. Plate number and peak capacity were systematically investigated under both isocratic and gradient elution conditions, respectively...
December 1, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/29193495/premature-birth-affects-the-degree-of-airway-dysanapsis-and-mechanical-ventilatory-constraints
#9
Joseph W Duke, Igor M Gladstone, A William Sheel, Andrew T Lovering
What is the central question of this study? Adult survivors of preterm birth without (PRE) and with bronchopulmonary dysplasia (BPD) have airflow obstruction at rest and significant mechanical ventilatory constraints during exercise compared with those born at full term (CON). Do PRE/BPD have smaller airways, indexed via the dysanapsis ratio, than CON? What is the main finding and its importance? The dysanapsis ratio was significantly smaller in BPD and PRE compared with CON, with BPD having the smallest dysanapsis ratio...
February 1, 2018: Experimental Physiology
https://www.readbyqxmd.com/read/29190612/assessment-of-bronchial-obstruction-using-lateral-pressure-measurement-during-bronchoscopy
#10
Hiroki Nishine, Takehiko Hiramoto, Takeo Inoue, Naoki Furuya, Hirotaka Kida, Hiroshi Handa, Seiichi Nobuyama, Masamichi Mineshita, Teruomi Miyazawa
BACKGROUND: In patients with bronchial obstruction estimating the location of the maximal obstruction is crucial for guiding interventional bronchoscopy. However, flow-volume curves cannot discriminate between the right and left lungs. OBJECTIVES: The aim of this study was to physiologically evaluate bronchial obstruction during interventional bronchoscopy. METHODS: We prospectively measured lateral airway pressure (Plat) at either side of the obstruction using a double-lumen catheter (pressure-pressure [P-P] curve) simultaneously to assess the degree of bronchial obstruction in 22 patients...
November 30, 2017: Respiration; International Review of Thoracic Diseases
https://www.readbyqxmd.com/read/29097129/recycling-potential-of-post-consumer-plastic-packaging-waste-in-finland
#11
Helena Dahlbo, Valeria Poliakova, Ville Mylläri, Olli Sahimaa, Reetta Anderson
Recycling of plastics is urged by the need for closing material loops to maintain our natural resources when striving towards circular economy, but also by the concern raced by observations of plastic scrap in oceans and lakes. Packaging industry is the sector using the largest share of plastics, hence packaging dominates in the plastic waste flow. The aim of this paper was to sum up the recycling potential of post-consumer plastic packaging waste in Finland. This potential was evaluated based on the quantity, composition and mechanical quality of the plastic packaging waste generated by consumers and collected as a source-separated fraction, within the mixed municipal solid waste (MSW) or within energy waste...
October 30, 2017: Waste Management
https://www.readbyqxmd.com/read/29080776/comprehensive-computational-assessment-of-blood-flow-characteristics-of-left-ventricle-based-on-in-vivo-mri-in-presence-of-artificial-myocardial-infarction
#12
Ali Imanparast, Nasser Fatouraee, Farhad Sharif
BACKGROUND: Understanding the effects of cardiac diseases on the heart's functionality which is the purpose of many biomedical researches, directly affects the diagnostic and therapeutic methods. Myocardial infarction (MI) is a common complication of cardiac ischemia, however, the impact of MI on the left ventricle (LV) flow patterns has not been widely considered by computational fluid dynamics studies thus far. METHODS: In this study, we present an insightful numerical method that creates an artificial MI on an image-based fluid-structure interactional model of normal LV to investigate its influence on the flow in comparison with the normal case...
October 26, 2017: Mathematical Biosciences
https://www.readbyqxmd.com/read/29067926/rare-tracheal-tumor-solitary-plasmacytoma
#13
R Stevic, M Ercegovac, J Stojšić, N Čolić
Primary tracheal tumors are rare and trachea is an exceedingly rare site of extramedullary plasmacytoma (EMP). We report a case of solitary tracheal plasmacytoma causing symptoms of airway obstruction in a 59-year-old man. Flow/volume loop indicated the fixed central airway obstruction. Computerized tomography and bronchoscopy demonstrated a sessile tumor on posterior tracheal wall obstructing 80% of the lumen. Partial tracheal resection with T-T anastomosis was performed. Pathologic analysis of resected mass revealed EMP...
October 23, 2017: Journal of Postgraduate Medicine
https://www.readbyqxmd.com/read/29056459/low-flow-support-of-the-chronic-pressure-overloaded-right-ventricle-induces-reversed-remodeling
#14
Tom Verbelen, Piet Claus, Daniel Burkhoff, Ronald B Driesen, Chandan Kadur Nagaraju, Erik Verbeken, Karin Sipido, Marion Delcroix, Filip Rega, Bart Meyns
BACKGROUND: Mechanical right ventricular (RV) support in pulmonary arterial hypertension patients has been feared to cause pulmonary hemorrhage and to be detrimental for the after-load-sensitive RV. Continuous low-flow pumps offer promise but remain insufficiently tested. METHODS: The pulmonary artery was banded in 20 sheep in this study. Eight weeks later, a Synergy micro-pump (HeartWare International, Framingham MA) was inserted in 10 animals, driving blood from the right atrium to the pulmonary artery...
September 29, 2017: Journal of Heart and Lung Transplantation
https://www.readbyqxmd.com/read/29053169/whole-body-physiologically-based-modelling-of-beta-blockers-in-the-rat-events-in-tissues-and-plasma-following-an-intravenous-bolus-dose
#15
S Y A Cheung, T Rodgers, L Aarons, I Gueorguieva, G L Dickinson, S Murby, C Brown, B Collins, M Rowland
BACKGROUND AND PURPOSE: Whole body physiologically based pharmacokinetic (PBPK) models have been increasingly applied in drug development to describe kinetic events of therapeutic agents in animals and human. The advantage of such modelling is the ability to incorporate vast amounts of physiological information, such as organ blood flow and volume, to ensure that the model is as close to reality as possible. EXPERIMENTAL APPROACH: Prior PBPK model development of enantiomers of a series of seven racemic betablockers, namely acebutolol, betaxolol, bisoprolol, metoprolol, oxprenolol, pindolol and propranolol, together with S-timolol in rat was based on tissue and blood concentration data at steady state...
October 20, 2017: British Journal of Pharmacology
https://www.readbyqxmd.com/read/29029075/improving-health-systems-performance-in-low-and-middle-income-countries-a-system-dynamics-model-of-the-pay-for-performance-initiative-in-afghanistan
#16
O Alonge, S Lin, T Igusa, D H Peters
System dynamics methods were used to explore effective implementation pathways for improving health systems performance through pay-for-performance (P4P) schemes. A causal loop diagram was developed to delineate primary causal relationships for service delivery within primary health facilities. A quantitative stock-and-flow model was developed next. The stock-and-flow model was then used to simulate the impact of various P4P implementation scenarios on quality and volume of services. Data from the Afghanistan national facility survey in 2012 was used to calibrate the model...
December 1, 2017: Health Policy and Planning
https://www.readbyqxmd.com/read/28985746/porcine-model-of-progressive-cardiac-hypertrophy-and-fibrosis-with-secondary-postcapillary-pulmonary-hypertension
#17
Mariann Gyöngyösi, Noemi Pavo, Dominika Lukovic, Katrin Zlabinger, Andreas Spannbauer, Denise Traxler, Georg Goliasch, Ljubica Mandic, Jutta Bergler-Klein, Alfred Gugerell, Andras Jakab, Zsuzsanna Szankai, Levente Toth, Rita Garamvölgyi, Gerald Maurer, Frederic Jaisser, Faiez Zannad, Thomas Thum, Sándor Bátkai, Johannes Winkler
BACKGROUND: Meaningful translational large animal models for cardiac diseases are indispensable for studying disease mechanisms, development of novel therapeutic strategies, and evaluation of potential drugs. METHODS: For induction of heart failure, cardiac hypertrophy and fibrosis, a bare metal stent was implanted in the descending aorta of growing pigs (n = 7), inducing pressure stress on the left ventricle (group HYPI). The constant stent size in growing pigs resulted in antegrade partial obstruction of the aortic flow with a gradual increase in afterload...
October 6, 2017: Journal of Translational Medicine
https://www.readbyqxmd.com/read/28977686/in-loop-flow-11-c-co2-fixation-and-radiosynthesis-of-n-n-11-c-dibenzylurea
#18
Joseph Downey, Salvatore Bongarzonev, Stefan Hader, Antony D Gee
Cyclotron-produced carbon-11 is a highly valuable radionuclide for the production of positron emission tomography (PET) radiotracers. It is typically produced as relatively unreactive carbon-11 carbon dioxide ([(11) C]CO2 ) which is most commonly converted into a more reactive precursor for synthesis of PET radiotracers. The development of [(11) C]CO2 fixation methods have more recently enabled the direct radiolabeling of a diverse array of structures directly from [(11) C]CO2 , and the advantages afforded by the use of a loop-based system employed in (11) C-methylation and (11) C-carboxylation reactions inspired us to apply the [(11) C]CO2 fixation "in-loop"...
October 4, 2017: Journal of Labelled Compounds & Radiopharmaceuticals
https://www.readbyqxmd.com/read/28961240/myocardial-wall-stiffening-in-a-mouse-model-of-persistent-truncus-arteriosus
#19
Christine Miller Buffinton, Alyssa K Benjamin, Ashley N Firment, Anne M Moon
BACKGROUND: Genetic and epigenetic programs regulate dramatic structural changes during cardiac morphogenesis. Concurrent biomechanical forces within the heart created by blood flow and pressure in turn drive downstream cellular, molecular and genetic responses. Thus, a genetic-morphogenetic-biomechanical feedback loop is continually operating to regulate heart development. During the evolution of a congenital heart defect, concomitant abnormalities in blood flow, hemodynamics, and patterns of mechanical loading would be predicted to change the output of this feedback loop, impacting not only the ultimate morphology of the defect, but potentially altering tissue-level biomechanical properties of structures that appear structurally normal...
2017: PloS One
https://www.readbyqxmd.com/read/28940225/treatment-of-refractory-ascites-with-an-automated-low-flow-ascites-pump-in-patients-with-cirrhosis
#20
G Stirnimann, T Berg, L Spahr, S Zeuzem, S McPherson, F Lammert, F Storni, V Banz, J Babatz, V Vargas, A Geier, A Stallmach, C Engelmann, C Trepte, J Capel, A De Gottardi
BACKGROUND: Refractory ascites (RA) is a frequent complication of cirrhosis, requiring large volume paracentesis or placement of a transjugular intrahepatic portosystemic shunt (TIPSS). The automated low-flow ascites pump (alfapump, Sequana Medical AG, Zurich, Switzerland) is an innovative treatment option for patients with RA. AIM: To assess safety and efficacy of this treatment in patients with a contraindication to TIPSS. METHODS: Fifty-six patients (43 males; mean age 62 years) from centres in Germany, Switzerland, UK and Spain were included and followed for up to 24 months...
November 2017: Alimentary Pharmacology & Therapeutics
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