The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Juan Antonio Sáez-nieto - One of the best experts on this subject based on the ideXlab platform.
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Outbreak of long-term intravascular catheter-related bacteremia due to Achromobacter xylosoxidans subspecies xylosoxidans in a hemodialysis unit
European Journal of Clinical Microbiology and Infectious Diseases, 2005Co-Authors: Daniel Tena, R. Carranza, J.r. Barberá, Sylvia Valdezate, J.m. Garrancho, M. Arranz, Juan Antonio Sáez-nietoAbstract:Achromobacter xylosoxidans is a rare cause of bacteremia. Over a 2-week period, A. xylosoxidans subsp. xylosoxidans was isolated from blood cultures of four hemodialysis patients with long-term intravascular catheters. A culture from one atomizer that contained diluted 2.5% chlorhexidine, which had been used to disinfect the skin, yielded A. xylosoxidans subsp. xylosoxidans. No further cases were diagnosed once the use of this atomizer was discontinued. Five outbreak-related strains from the four patients and the atomizer were tested by pulsed-field gel electrophoresis (PFGE) under Xba I restriction. The isolates from the first three patients and the atomizer had identical PFGE patterns, confirming the atomizer as the source of the outbreak. The strain isolated from the fourth patient had six more bands than the outbreak strain and was considered possibly related to the outbreak strain. All patients were treated with intravenous levofloxacin. The catheter was removed in only one patient. The three patients in whom the catheter was left in place were also treated with antibiotic lock therapy with levofloxacin. All four patients were cured. This is believed to be the first reported outbreak of central venous catheter-related bacteremia due to A. xylosoxidans and the second reported outbreak with this organism associated with chlorhexidine Atomizers. The use of diluted chlorhexidine via Atomizers can be dangerous for the care of venous catheters and should be called into question. Patients with long-term intravascular catheter-related bacteremia due to this organism can be treated successfully with systemic antimicrobial therapy in addition to antibiotic lock therapy without catheter removal.
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Outbreak of long-term intravascular catheter-related bacteremia due to Achromobacter xylosoxidans subspecies xylosoxidans in a hemodialysis unit
European Journal of Clinical Microbiology and Infectious Diseases, 2005Co-Authors: Daniel Tena, R. Carranza, J.r. Barberá, Sylvia Valdezate, J.m. Garrancho, M. Arranz, Juan Antonio Sáez-nietoAbstract:Achromobacter xylosoxidans is a rare cause of bacteremia. Over a 2-week period, A. xylosoxidans subsp. xylosoxidans was isolated from blood cultures of four hemodialysis patients with long-term intravascular catheters. A culture from one atomizer that contained diluted 2.5% chlorhexidine, which had been used to disinfect the skin, yielded A. xylosoxidans subsp. xylosoxidans. No further cases were diagnosed once the use of this atomizer was discontinued. Five outbreak-related strains from the four patients and the atomizer were tested by pulsed-field gel electrophoresis (PFGE) under Xba I restriction. The isolates from the first three patients and the atomizer had identical PFGE patterns, confirming the atomizer as the source of the outbreak. The strain isolated from the fourth patient had six more bands than the outbreak strain and was considered possibly related to the outbreak strain. All patients were treated with intravenous levofloxacin. The catheter was removed in only one patient. The three patients in whom the catheter was left in place were also treated with antibiotic lock therapy with levofloxacin. All four patients were cured. This is believed to be the first reported outbreak of central venous catheter-related bacteremia due to A. xylosoxidans and the second reported outbreak with this organism associated with chlorhexidine Atomizers. The use of diluted chlorhexidine via Atomizers can be dangerous for the care of venous catheters and should be called into question. Patients with long-term intravascular catheter-related bacteremia due to this organism can be treated successfully with systemic antimicrobial therapy in addition to antibiotic lock therapy without catheter removal.
Daniel Tena - One of the best experts on this subject based on the ideXlab platform.
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Outbreak of long-term intravascular catheter-related bacteremia due to Achromobacter xylosoxidans subspecies xylosoxidans in a hemodialysis unit
European Journal of Clinical Microbiology and Infectious Diseases, 2005Co-Authors: Daniel Tena, R. Carranza, J.r. Barberá, Sylvia Valdezate, J.m. Garrancho, M. Arranz, Juan Antonio Sáez-nietoAbstract:Achromobacter xylosoxidans is a rare cause of bacteremia. Over a 2-week period, A. xylosoxidans subsp. xylosoxidans was isolated from blood cultures of four hemodialysis patients with long-term intravascular catheters. A culture from one atomizer that contained diluted 2.5% chlorhexidine, which had been used to disinfect the skin, yielded A. xylosoxidans subsp. xylosoxidans. No further cases were diagnosed once the use of this atomizer was discontinued. Five outbreak-related strains from the four patients and the atomizer were tested by pulsed-field gel electrophoresis (PFGE) under Xba I restriction. The isolates from the first three patients and the atomizer had identical PFGE patterns, confirming the atomizer as the source of the outbreak. The strain isolated from the fourth patient had six more bands than the outbreak strain and was considered possibly related to the outbreak strain. All patients were treated with intravenous levofloxacin. The catheter was removed in only one patient. The three patients in whom the catheter was left in place were also treated with antibiotic lock therapy with levofloxacin. All four patients were cured. This is believed to be the first reported outbreak of central venous catheter-related bacteremia due to A. xylosoxidans and the second reported outbreak with this organism associated with chlorhexidine Atomizers. The use of diluted chlorhexidine via Atomizers can be dangerous for the care of venous catheters and should be called into question. Patients with long-term intravascular catheter-related bacteremia due to this organism can be treated successfully with systemic antimicrobial therapy in addition to antibiotic lock therapy without catheter removal.
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Outbreak of long-term intravascular catheter-related bacteremia due to Achromobacter xylosoxidans subspecies xylosoxidans in a hemodialysis unit
European Journal of Clinical Microbiology and Infectious Diseases, 2005Co-Authors: Daniel Tena, R. Carranza, J.r. Barberá, Sylvia Valdezate, J.m. Garrancho, M. Arranz, Juan Antonio Sáez-nietoAbstract:Achromobacter xylosoxidans is a rare cause of bacteremia. Over a 2-week period, A. xylosoxidans subsp. xylosoxidans was isolated from blood cultures of four hemodialysis patients with long-term intravascular catheters. A culture from one atomizer that contained diluted 2.5% chlorhexidine, which had been used to disinfect the skin, yielded A. xylosoxidans subsp. xylosoxidans. No further cases were diagnosed once the use of this atomizer was discontinued. Five outbreak-related strains from the four patients and the atomizer were tested by pulsed-field gel electrophoresis (PFGE) under Xba I restriction. The isolates from the first three patients and the atomizer had identical PFGE patterns, confirming the atomizer as the source of the outbreak. The strain isolated from the fourth patient had six more bands than the outbreak strain and was considered possibly related to the outbreak strain. All patients were treated with intravenous levofloxacin. The catheter was removed in only one patient. The three patients in whom the catheter was left in place were also treated with antibiotic lock therapy with levofloxacin. All four patients were cured. This is believed to be the first reported outbreak of central venous catheter-related bacteremia due to A. xylosoxidans and the second reported outbreak with this organism associated with chlorhexidine Atomizers. The use of diluted chlorhexidine via Atomizers can be dangerous for the care of venous catheters and should be called into question. Patients with long-term intravascular catheter-related bacteremia due to this organism can be treated successfully with systemic antimicrobial therapy in addition to antibiotic lock therapy without catheter removal.
Jiří Dědina - One of the best experts on this subject based on the ideXlab platform.
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Behavior of selenium hydride in heated quartz tube and dielectric barrier discharge Atomizers.
Analytica Chimica Acta, 2018Co-Authors: Jan Kratzer, Stanislav Musil, Tomáš Matoušek, Ralph E Sturgeon, Zoltan Mester, Karel Marschner, Milan Svoboda, Jiří DědinaAbstract:Abstract Atomization of SeH2 in an externally heated multiple microflame quartz tube atomizer (MMQTA) as well as planar dielectric barrier discharge (DBD) atomizer was investigated using a variety of probes. Deposits of Se on inner surfaces of the Atomizers were quantified and their distribution visualized by autoradiography with 75Se radiotracer. The gas phase fraction of Se transported beyond the confines of the Atomizers was also determined. In the MMQTA, a 15% mass fraction of Se was deposited in a narrow zone at both colder ends of the optical arm (100–400 °C). By contrast, a 25-40% mass fraction of Se was deposited homogeneously along the entire length of the optical arm of the DBD, depending on detection technique employed. The fraction of Se transported outside the MMQTA approached 90%, whereas it was 50–70% in the DBD. The presence of H2 was essential for atomization of selenium hydride in both Atomizers. The gaseous effluent arising from the hydride generator as well as the Atomizers was investigated by direct analysis in real time (DART) coupled to an Orbitrap-mass spectrometer, enabling identification of major gas phase species of Se.
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flame in gas shield and miniature diffusion flame hydride Atomizers for atomic fluorescence spectrometry optimization and comparison
Spectrochimica Acta Part B: Atomic Spectroscopy, 2015Co-Authors: Karel Marschner, Stanislav Musil, Jiří DědinaAbstract:Abstract A detailed optimization of relevant experimental parameters of two hydride Atomizers for atomic fluorescence spectrometry: flame-in-gas-shield atomizer with a two-channel shielding unit and a standard atomizer for atomic fluorescence spectrometry, miniature diffusion flame, was performed. Arsine, generated by the reaction with NaBH 4 in a flow injection arrangement, was chosen as the model hydride. Analytical characteristics of both the Atomizers (sensitivity, noise, limits of detection) were compared. Under optimum conditions sensitivity obtained with flame-in-gas-shield atomizer was approximately twice higher than with miniature diffusion flame. The additional advantage of flame-in-gas-shield atomizer is significantly lower flame emission resulting in a better signal to noise ratio. The resulting arsenic limits of detection for miniature diffusion flame and flame-in-gas-shield atomizer were 3.8 ng l − 1 and 1.0 ng l − 1 , respectively.
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Atomization of volatile compounds for atomic absorption and atomic fluorescence spectrometry: On the way towards the ideal atomizer
Spectrochimica Acta Part B: Atomic Spectroscopy, 2007Co-Authors: Jiří DědinaAbstract:Abstract This review summarizes and discusses the individual Atomizers of volatile compounds. A set of criteria important for analytical praxis is used to rank all the currently existing approaches to the atomization based on on-line atomization for atomic absorption (AAS) and atomic fluorescence spectrometry (AFS) as well as on in-atomizer trapping for AAS. Regarding on-line atomization for AAS, conventional quartz tubes are currently the most commonly used devices. They provide high sensitivity and low baseline noise. Running and investment costs are low. The most serious disadvantage is the poor resistance against atomization interferences and often unsatisfactory linearity of calibration graphs. Miniature diffusion flame (MDF) is extremely resistant to interferences, simple, cheap and user-friendly. Its essential disadvantage is low sensitivity. A novel device, known as a multiatomizer, was designed to overcome disadvantages of previous Atomizers. It matches performance of conventional quartz tubes in terms of sensitivity and baseline noise as well as in running and investment costs. The multiatomizer, however, provides much better (i) resistance against atomization interferences and (ii) linearity of calibration graphs. In-atomizer trapping enhances the sensitivity of the determination and eliminates the effect of the generation kinetics and of surges in gas flow on the signal shape. This is beneficial for the accuracy of the determination. It could also be an effective tool for reducing some interferences in the liquid phase. In-situ trapping in graphite furnaces (GF) is presently by far the most popular approach to the in-atomizer trapping. Its resistance against interferences is reasonably good and it can be easily automated. In-situ trapping in GF is a mature method well established in various application fields. These are the reasons to rank in-situ trapping in GF as currently the most convenient approach to hydride atomization for AAS. The recently suggested approach, trapping on quartz surfaces in an excess of oxygen with subsequent atomization in multiatomizer or in conventional quartz tubes, is very promising. It requires only simple and cheap equipment. The potential to reach very low detection limits is even better than for in-situ trapping in GF. However, it is a novel method which will have to be tested more extensively before it can considered to be a tool for routine analysis. Almost all the applications of AFS employ a miniature diffusion flame for the atomization. The alternative, the flame-in-gas-shield atomizer, is more complicated but it offers a substantially better signal to noise ratio. The current state-of-the-art of all individual Atomizers, including advantages, drawbacks and perspectives, is recapitulated in detail. Also the most recent knowledge of the mechanism of processes taking place in the Atomizers is treated.
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Quartz tube Atomizers for hydride generation atomic absorption spectrometry: fate of free arsenic atoms
Spectrochimica Acta Part B: Atomic Spectroscopy, 1993Co-Authors: Jiří Dědina, Bernhard WelzAbstract:Abstract The effect of atomizer design, purge hydrogen flow rate and atomizer temperature on the sensitivity of arsenic in quartz tube Atomizers was investigated. A variety of Atomizers of two basic designs (externally heated or unheated flame-in-tube Atomizers and externally heated “flameless” Atomizers of different dimensions) were employed. The following conclusions have been drawn from the experiments and thermodynamic equilibrium calculations: factors influencing analyte transfer prior to atomization include surface temperature, atomizer dimension and gas flow; the decay of free analyte atoms is controlled by the pattern of gas flow; in a T-shaped atomizer, there is an important zone of turbulence in the junction, whereas a laminar flow pattern prevails in the remaining part of the tube; substantial decay takes place within the turbulent zone; and the decay in the laminar zone is significant only for low gas flow rate and in broader tubes. Decayed As species are volatile and can be completely reatomized in an additional flame downstream in the atomizer. They cannot be reatomized, however, in a heated atomizer without a separate oxygen inlet. Emerging possibilities for improvement of sensitivity and for a reduction of atomization interferences by optimizing the design of quartz tube Atomizers are discussed.
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Quartz tube Atomizers for hydride generation atomic absorption spectrometry: mechanism of selenium hydride atomization and fate of free atoms
Spectrochimica Acta Part B: Atomic Spectroscopy, 1992Co-Authors: Jiří DědinaAbstract:Abstract The influence of the purge gas type and its flow, as well as the oxygen supply and the temperature on the selenium sensitivity of a commercial, externally heated quartz tube atomizer, was investigated. The gas flow acts analogously as in the flame-in-tube Atomizers, and the type of gas influences the atomic absorption coefficient. There is a synergic effect of oxygen supply and temperature on the sensitivity in a broad temperature range starting below 600°C. The higher the temperature, the lower oxygen supply required to achieve optimum sensitivity. A “hybrid” hydride atomizer, capable of working as either a flame-in-tube atomizer or an externally heated quartz tube atomizer, or in several combined modes, was employed to investigate hydride atomization and analyte transfer in quartz tube Atomizers. The following conclusions have been drawn from the experiments: (i) There is no fundamental difference between both types of quartz tube Atomizers, externally heated quartz Atomizers being, in fact, oxygen-deficient, externally heated flame-in-tube Atomizers. Hydride atomization takes place in a small cloud of hydrogen radicals located at the entrance to the heated portion of the cell. The decay of analyte free atoms takes place on the whole inner atomizer surface; (ii) The decay rate increases with temperature. This increase is much more pronounced if the surface is contaminated. The contamination does not affect the efficiency of atomization in the radical cloud; (iii) Typically, the sensitivity is controlled by the rate of free atom decay; and (iv) Decayed Se species are volatile-they can be completely reatomized in an additional flame downstream in the atomizer either externally heated or unheated. They cannot be atomized at all in a heated atomizer without a separate oxygen inlet.
Jan Jedelsky - One of the best experts on this subject based on the ideXlab platform.
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internal flow dynamics of spill return pressure swirl Atomizers
Experimental Thermal and Fluid Science, 2021Co-Authors: Milan Malý, Marcel Sapik, Graham Wigley, Ondrej Cejpek, Vladimir Ondracek, Jan JedelskyAbstract:Abstract The sprays produced by spill-return pressure-swirl Atomizers are strongly dependent on the nature of the internal fluid dynamics. Several spill-return Atomizers were compared in terms of the spatial and temporal behaviour of the internal air-core, liquid sheet thickness and its perturbations. The only difference amongst the test configurations was the geometrical arrangement of the spill-line (SL) orifice through which the liquid was spilled away. The flow field inside the swirl chamber was examined using high-speed imaging with image post processing using an in-house Matlab code and three orthogonal velocity components acquired using Laser Doppler Anemometry. The dimensions of the production Atomizers did not allow direct visualization of their internal flow, so a scaled, modular, transparent plexiglass model was used. Its flow characteristics were equivalent to the original atomizer. The refractive index of the atomizer body was matched to the test liquid using a solution of 1-Bromonaphthalene and kerosene fuel type JET A-1. The test conditions were derived from the original atomizer and were limited to inlet port Reynolds numbers, from 700 to 2000 and spill-to-feed ratios, SFR, from 0 to 0.75. An inviscid analysis, originally derived for Simplex Atomizers, was modified and applied to the spill-return version. This approach allows a theoretical prediction of the discharge coefficient and air-core diameter dependent solely on SFR. An axially located SL orifice inhibits any internal air-core forming in the swirl chamber. Off-axial SL orifices generate and stabilize the air-core, which leads to the regular formation of a liquid sheet and a high-quality spray. Nevertheless, some configurations changed the breakup nature of the liquid sheet and consequently the spray quality. Moreover, the turn-down ratio of the liquid supply rate and spray stability depend on the distance of the SL orifices from the swirl chamber centreline. The flow energy losses increase with SFR. The outcomes from this analysis allow the optimization of the SL configuration for specific application and extend the classical inviscid analysis.
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Replication of Pressure Swirl Atomizer by 3D Printing and Influence of Surface Roughness on the Atomization Quality
MATEC Web of Conferences, 2020Co-Authors: Ondřej Cejpek, Milan Malý, Miloslav Bělka, Jan JedelskyAbstract:The replication of Atomizers by 3D printing technology is a new approach of producing the pressure swirl Atomizers. The surface roughness of 3D printed products and manufacturing accuracy of the 3D printing process influence the atomization of the liquid. The high-speed visualization of a spray, produced by scaled 3D printed atomizer, was performed. The spray stability, cone angle and breakup length were determined. Scaled 3D printed Atomizers were tested at equivalent pressures of 0.25, 0.5 and 1 bar. Non-dimensionless parameter, Reynolds number, was preserved for the scaled atomizer. The effect of the surface roughness of the tangential ports, swirl chamber and discharge orifice on atomization was assessed at non-scaled pressure swirl atomizer. The roughness of a swirl chamber was created by corundum and ballotin blasting. The inlet pressures of 2.5, 5 and 10 bar were tested.
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effect of spill orifice geometry on spray and control characteristics of spill return pressure swirl Atomizers
Experimental Thermal and Fluid Science, 2019Co-Authors: Milan Malý, Ondřej Cejpek, Marcel Sapik, Graham Wigley, Jaroslav Katolicky, Jan JedelskyAbstract:Abstract Many spray process technologies require variable liquid flow rates or droplet sizes. Frequently used Simplex Atomizers, favoured for their simple construction, reliability and fine spray, have a limited regulation range due to their flow rate dependency on the square root of the inlet overpressure, pl. To overcome this drawback, spill-return versions of the atomizer were developed in the past but so far rarely investigated in depth. In this paper, small spill-return Atomizers (SRAs) were designed and investigated experimentally using Phase Doppler Anemometry (PDA) and high-speed imaging with the aim to determine the effect of the spill orifice design, e.g. the positioning of the axial and off-axis spill orifices, their number and inclination on the control characteristics, nozzle efficiency and spray characteristics. Such detailed data were not to be found in the open literature. The off-axial spill orifice version produced a stable spray under all flow regimes investigated while the axially positioned spill orifice provided an unstable spray for low spill-to-feed ratios (SFR). However, the axially placed spill orifice was found to be more energy efficient as it required a lower spill flow rate to achieve the same injection flow rate. The radial position of the spill orifices affected the turndown ratio and liquid breakup nature. The Atomizers with spill orifices placed close to the swirl chamber centreline generated a liquid sheet which disintegrated in short-wave breakup mode while the other Atomizers demonstrated a long-wave breakup mode. This mode produced longer liquid breakup length and formed droplets with smaller Sauter mean diameters. Atomization efficiency was found to decrease linearly with SFR and almost inversely proportional to pl. These findings have produced practical guidelines and recommendations for atomizer designs to suit specific goals and are addressed to both atomizer designers and application engineers. The experimental data form a significant base to validate advanced numerical simulations of the SRA sprays.
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internal flow and air core dynamics in simplex and spill return pressure swirl Atomizers
International Journal of Heat and Mass Transfer, 2017Co-Authors: Milan Malý, Jan Jedelsky, Jaroslav Slama, Lada Janackova, Marcel Sapik, Graham WigleyAbstract:Abstract Spill-return (SR) Atomizers enhance the construction of Simplex Atomizers by addition of a passage in the rear wall of the swirl chamber through which the liquid can be spilled away. It allows to discharge the liquid always at a high pressure and to spray well over a wide flow rate range. The spray characteristics of pressure-swirl Atomizers are strongly linked to the internal flow, and the air-core dynamics affect the spray stability. The SR Atomizers are rarely investigated and their internal flow is not studied at all. Therefore, in this paper, the Simplex and SR Atomizers with a central SR orifice were examined comparatively. Transparent polymethyl methacrylate (PMMA) models of both Atomizers scaled 10:1 were manufactured for the visualization and velocity measurements of the flow inside the swirl chamber. The Atomizers were examined by means of high-speed imaging, laser-Doppler anemometry and computational fluid dynamics tools. The experimental and numerical results were analysed and compared in terms of the spray cone angle (SCA), discharge coefficient (CD), and the morphology and temporal stability of the air core. The internal flow characteristics between the original and the model atomizer were matched using the Reynolds, Swirl and Froude numbers. The test conditions were limited to inlet Reynolds numbers from 750 to 1750. The results show that the addition of the spill passage strongly affects the internal flow even when the spill-line is closed. The air core in the Simplex atomizer is fully developed and stable for all flow regimes. The SR atomizer behaves differently; with the closed spill-line (spill-to-feed ratio, SFR = 0), the air core does not form at all; therefore, the spray is unstable. The reason is that the liquid, contained in the spill-line, is drained back into the swirl chamber due to a recirculation zone found inside the spill-line. Increasing the SFR stabilizes the internal flow, and the spray becomes stable if SFR > 0.15. The air core begins to form for SFR > 0.4. The results suggest that the axially positioned spill orifice is inappropriate and its placing off-axis would improve the spray stability. The results of the 2D numerical simulation matched closely with the experiments in terms of SCA, CD, velocity profiles, and air core morphology which proved its prediction capabilities.
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twin fluid atomization of viscous liquids the effect of atomizer construction on breakup process spray stability and droplet size
International Journal of Multiphase Flow, 2015Co-Authors: Marek Mlkvik, Philipp Stahle, Volker Gaukel, Jan Jedelsky, Heinz-peter Schuchmann, Miroslav JichaAbstract:Abstract This study focuses on the low-pressure spraying of viscous liquids ( μ = 60, 147 and 308 mPa s) using four types of internal-mixing twin-fluid Atomizers. We compare two well-known designs, namely the Y-jet and “outside in gas” (OIG) effervescent Atomizers, with our new design (CFT) and an “outside in liquid” (OIL) configuration for the effervescent atomizer. The Atomizers were operated by two gas inlet pressures (0.14 and 0.28 MPa) and various gas-to-liquid ratios (GLR = 2.5%, 5%, 10% and 20%). The comparison focused on internal liquid–gas flow, spray stability, primary breakup, and droplet size. The primary breakup was investigated using a high-speed camera. A near-nozzle spray pattern was related to the ratio of forces, which affects liquid deformation, by dimensionless numbers. The breakup was driven mainly by air resistance in the OIG, OIL, and CFT Atomizers and by surface tension in the Y-jet atomizer. The OIL and Y-jet Atomizers provided the most stable spray, regardless of the working regime or atomized liquid. The OIL atomizer produced the smallest droplets at low GLRs, while the droplet sizes for the Y-jet atomizer increased significantly at low GLRs. For the OIG atomizer, spray stability was influenced by the GLR, with the best stability being achieved at a GLR of 10% and 20%. The presence of large droplets at a low GLR caused an increase in droplet size. Switching the inlet ports of the effervescent atomizer (OIG–OIL) affected the internal flow, which differed under the same working regimes for these two configurations. The internal flow pattern of the OIL atomizer was estimated to be annular for all regimes, while for the OIG atomizer, it changed from a plug to slug flow with an increase in the GLR.
Sylvia Valdezate - One of the best experts on this subject based on the ideXlab platform.
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Outbreak of long-term intravascular catheter-related bacteremia due to Achromobacter xylosoxidans subspecies xylosoxidans in a hemodialysis unit
European Journal of Clinical Microbiology and Infectious Diseases, 2005Co-Authors: Daniel Tena, R. Carranza, J.r. Barberá, Sylvia Valdezate, J.m. Garrancho, M. Arranz, Juan Antonio Sáez-nietoAbstract:Achromobacter xylosoxidans is a rare cause of bacteremia. Over a 2-week period, A. xylosoxidans subsp. xylosoxidans was isolated from blood cultures of four hemodialysis patients with long-term intravascular catheters. A culture from one atomizer that contained diluted 2.5% chlorhexidine, which had been used to disinfect the skin, yielded A. xylosoxidans subsp. xylosoxidans. No further cases were diagnosed once the use of this atomizer was discontinued. Five outbreak-related strains from the four patients and the atomizer were tested by pulsed-field gel electrophoresis (PFGE) under Xba I restriction. The isolates from the first three patients and the atomizer had identical PFGE patterns, confirming the atomizer as the source of the outbreak. The strain isolated from the fourth patient had six more bands than the outbreak strain and was considered possibly related to the outbreak strain. All patients were treated with intravenous levofloxacin. The catheter was removed in only one patient. The three patients in whom the catheter was left in place were also treated with antibiotic lock therapy with levofloxacin. All four patients were cured. This is believed to be the first reported outbreak of central venous catheter-related bacteremia due to A. xylosoxidans and the second reported outbreak with this organism associated with chlorhexidine Atomizers. The use of diluted chlorhexidine via Atomizers can be dangerous for the care of venous catheters and should be called into question. Patients with long-term intravascular catheter-related bacteremia due to this organism can be treated successfully with systemic antimicrobial therapy in addition to antibiotic lock therapy without catheter removal.
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Outbreak of long-term intravascular catheter-related bacteremia due to Achromobacter xylosoxidans subspecies xylosoxidans in a hemodialysis unit
European Journal of Clinical Microbiology and Infectious Diseases, 2005Co-Authors: Daniel Tena, R. Carranza, J.r. Barberá, Sylvia Valdezate, J.m. Garrancho, M. Arranz, Juan Antonio Sáez-nietoAbstract:Achromobacter xylosoxidans is a rare cause of bacteremia. Over a 2-week period, A. xylosoxidans subsp. xylosoxidans was isolated from blood cultures of four hemodialysis patients with long-term intravascular catheters. A culture from one atomizer that contained diluted 2.5% chlorhexidine, which had been used to disinfect the skin, yielded A. xylosoxidans subsp. xylosoxidans. No further cases were diagnosed once the use of this atomizer was discontinued. Five outbreak-related strains from the four patients and the atomizer were tested by pulsed-field gel electrophoresis (PFGE) under Xba I restriction. The isolates from the first three patients and the atomizer had identical PFGE patterns, confirming the atomizer as the source of the outbreak. The strain isolated from the fourth patient had six more bands than the outbreak strain and was considered possibly related to the outbreak strain. All patients were treated with intravenous levofloxacin. The catheter was removed in only one patient. The three patients in whom the catheter was left in place were also treated with antibiotic lock therapy with levofloxacin. All four patients were cured. This is believed to be the first reported outbreak of central venous catheter-related bacteremia due to A. xylosoxidans and the second reported outbreak with this organism associated with chlorhexidine Atomizers. The use of diluted chlorhexidine via Atomizers can be dangerous for the care of venous catheters and should be called into question. Patients with long-term intravascular catheter-related bacteremia due to this organism can be treated successfully with systemic antimicrobial therapy in addition to antibiotic lock therapy without catheter removal.