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The recent COVID-19 pandemic has propelled the field of aerosol science to the forefront, particularly the central role of virus-laden respiratory droplets and aerosols. The pandemic has also highlighted the critical need, and value for, an information bridge between epidemiological models (that inform policymakers to develop public health responses) and within-host models (that inform the public and health care providers how individuals develop respiratory infections). Here, we review existing data and models of generation of respiratory droplets and aerosols, their exhalation and inhalation, and the fate of infectious droplet transport and deposition throughout the respiratory tract. We then articulate how aerosol transport modeling can serve as a bridge between and guide calibration of within-host and epidemiological models, forming a comprehensive tool to formulate and test hypotheses about respiratory tract exposure and infection within and between individuals.

Optimal management of chronic rhinosinusitis (CRS) endotypes includes post-operative application of topical formulations. There is little evidence regarding the ideal aerosol delivery characteristics and techniques to achieve the most efficient deposition on affected sinus mucosa. Nebulisers provide an alternative to nasal sprays by producing smaller particle sizes at lower velocities. We applied a reverse-particle-tracking simulation using computational fluid dynamics (CFD) to evaluate the ideal aerosol characteristics from a nebuliser to target the post-operative maxillary sinus mucosa. A CT scan of a CRS patient was used to create a pre-operative and virtual post-operative model. Particles of diameter 2 to 30 µm were tracked through the sinonasal cavity at 5, 10 and 15 L min–1 flow rates using CFD. Reverse particle simulations demonstrated that the optimised combination of parameters were 20 µm particles, delivered at 5 m s–1 (or 14 microns, delivered at 15 m s–1) at an inhalation rate of 5 L min–1, released from a nozzle in an elliptical oblique-superior direction into the superior half of the nasal valve significantly improved the maximum deposition efficiency (from 3% up to 55%) in the post-operative maxillary sinus mucosa. The nebulised spray (without optimisation) demonstrated negligible particle deposition within the sinuses of the pre-op model, while it increased marginally in the post-op model for smaller diameter particles at lower inhalation rates. The ideal combination of parameters to achieve targeted medication deposition on specific sinus mucosal surfaces can guide the development of new nasal drug delivery devices that produce the desired deposition regions for clinical applications in post-operative CRS patients.

Quantification of airway deposition of aerosol particles is essential for the assessment of health risks of detrimental particles. Knowledge of deposition distribution is important also in the case of treatment with aerosolised drugs. It is also worth considering that deposition of inhaled particles in severe asthmatics can be different from the deposition in healthy subjects due to the modified breathing parameters, airway geometry and lobar flow distribution. The aim of this study was to apply combined experimental and numerical techniques to quantify the upper airway and bronchial deposition of the inhaled microparticles in healthy individuals in comparison with asthma patients. Idealised and realistic physical and digital replicas of the human airways were constructed. Deposition fractions and efficiencies of inhaled polydisperse mannitol and chitosan particles in different airway sections were measured and calculated. Deposition fraction of polydisperse mannitol particles in the idealised airway geometry assuming breathing conditions of healthy subjects was 21.9% and 18.3% when determined experimentally and by numerical simulations, respectively. Experimental measurements of deposition fraction of chitosan particles in the same geometry, but assuming breathing parameters characteristic of severe asthmatics yielded 32%, while simulations provided 30.1% for the same conditions. Extrathoracic deposition fraction of mannitol particles in healthy subjects measured in the realistic geometry was 71.1%, while bronchial deposition fraction was 5.3%. The corresponding simulations yielded 76.2% and 8.9% deposition fractions in the upper and bronchial airways, respectively. There was a good agreement between the experimental and simulation deposition results also in the different predefined sections of the airways. Present pilot study proved that lobar flow redistribution due to severe asthma significantly modified the deposition distribution of micro-particles. Although t

Knowledge of particle deposition is important in clinical settings or when discussing environmental effects of aerosols on humans. Particle deposition in the human respiratory tract is determined by breathing patterns and lung morphology, as well as particle properties and deposition mechanisms. In this study we develop a 1-dimensional model that numerically solves the general dynamic aerosol equation in the human respiratory tract. The model can be used to calculate deposition fractions for a range of initial parameters. We use Weibel's morphometric model to describe the lung geometry. The model is validated by comparing it with previous numerical results, and running sensitivity tests to examine its consistency with parametric variations. The model proved to be computationally efficient, requiring just seconds to run a simulation. We use this to perform a number of parametric studies, most notably changing the tidal volume and the breathing rate. For both of these, an increase in either the volume or the rate decreased the deposition fraction across the spectrum of particle sizes, apart from at the tails of the distribution. We also examine the effect of particle density on the deposition fraction, which increases with an increasing density. The source code is published along with this thesis, allowing anyone to perform arbitrary parametric studies of their own., Applied Mathematics | Applied Physics

Combustion is one of the most difficult processes to model. Luminous flames are characteristically sooty, which creates a problem when modeling and calculating the combustion and heat transfer of the process; both of which are highly dependent on temperature and emissivity. Soot particle emissivity as well as gas contributions affect the heat transfer calculation and must be accounted for. Thermographic phosphors (TP) are ceramic based phosphorescent materials that have a temperature dependent emission that can be exploited to obtain surface and gas temperature measurements, as well as 2D temperature maps. Emissivity knowledge is not needed to obtain temperature and is not affected by the flame radiation emissions. However, since the TP is attached to the sample and it can also float into the gas/flame, the emissivity is still needed for heat transfer and energy balance calculations. The focus of this work is to study and measure the thermal radiation emissivity of Dysprosium doped Yttrium Aluminum Garnate (YAG:Dy) and Manganese doped Magnesium Fluorogermanate (MFG:Mn). Tests were conducted on both an Aerosol Deposited or AD (room temperature coating method that plastically deforms and bonds the particles onto the surface) and a “painted-on” (powder mixed with alcohol and brushed on the substrate) stainless steel sample. A Sandia LED driver, with a UV LED (365nm), was used as the light source to illuminate the samples inside a Watlow heater. These samples were submitted to a temperature range of 50-550ᵒC at approximately 50ᵒC steps; the data was collected utilizing a FLIR A655 camera. The YAG:Dy temperature vs. emissivity curve is fairly stable. On the other hand, for the MFG:Mn, the emissivity decreases with temperature. For both AD samples, compared to the “painted-on” samples, a decrease in emissivity is shown which is still being investigated.

Quantification of airway deposition of aerosol particles is essential for the assessment of health risks of detrimental particles. Knowledge of deposition distribution is important also in the case of treatment with aerosolised drugs. It is also worth considering that deposition of inhaled particles in severe asthmatics can be different from the deposition in healthy subjects due to the modified breathing parameters, airway geometry and lobar flow distribution. The aim of this study was to apply combined experimental and numerical techniques to quantify the upper airway and bronchial deposition of the inhaled microparticles in healthy individuals in comparison with asthma patients. Idealised and realistic physical and digital replicas of the human airways were constructed. Deposition fractions and efficiencies of inhaled polydisperse mannitol and chitosan particles in different airway sections were measured and calculated. Deposition fraction of polydisperse mannitol particles in the idealised airway geometry assuming breathing conditions of healthy subjects was 21.9% and 18.3% when determined experimentally and by numerical simulations, respectively. Experimental measurements of deposition fraction of chitosan particles in the same geometry, but assuming breathing parameters characteristic of severe asthmatics yielded 32%, while simulations provided 30.1% for the same conditions. Extrathoracic deposition fraction of mannitol particles in healthy subjects measured in the realistic geometry was 71.1%, while bronchial deposition fraction was 5.3%. The corresponding simulations yielded 76.2% and 8.9% deposition fractions in the upper and bronchial airways, respectively. There was a good agreement between the experimental and simulation deposition results also in the different predefined sections of the airways. Present pilot study proved that lobar flow redistribution due to severe asthma significantly modified the deposition distribution of micro-particles. Although t

The demand for nanoparticles in various applications is increasing. These applications can only be realised if nanoparticles can be specifically arranged and patterned on a substrate. This thesis considers a direct write method that uses an aerodynamic focusing nozzle to deposit these particles. A major challenge arises when the nanoparticles are decreased in size. This research studies the control of the deposition resolution of small sized nanoparticles (≤10 nm) in an aerosol flow. A FEM model was developed to describe the particle’s path. These models were made for a converging and converging sheath gas nozzle. Due to the small particle sizes considered, it was found that only the Stokes (drag) force needs to be accounted for during modelling. The effect of different nozzle exit throat, working distance, angle and flow rate configurations are studied. Nozzle designs were evaluated using three performance criteria, namely the contraction factor, focusing ratio and line width. These describe the contraction of the particles within the nozzle system, the focusing after the nozzle system and the width of the line, respectively. It was found that smaller angles, longer converging sections and higher velocities resulted in smaller line widths. Also, the contraction factor hardly depends on the particle size. Smaller nozzle exit throats have significantly higher focusing ratios for particles smaller than 10 nm. The working distance does not effect the contraction factor directly, indicating capabilities of deposition on non-flat surfaces. The converging nozzles can only deposit ≤10 nm particles if the nozzle exits are sufficiently small. This can cause clogging. The focusing ratios, in these nozzles, never exceeds the value of one, indicating always a larger line width than the nozzle exit diameter. In the sheath gas nozzle system, high sheath gas ratios are essential for increasing the contraction factor and particle velocity. This prevents clogging. Introduci

Understanding the biogeochemical cycles and distribution of trace elements in the marine environment is one of the main challenges in chemical oceanography. We describe herein the trace metal composition of the uppermost surface ocean of various oceanographic regions (Arctic and Southern Oceans, subtropical Atlantic Ocean, and Mediterranean Sea). Our results show that trace metals in the top meter of the ocean are found in two clearly differentiated layers according to metal abundance and stoichiometry, namely the surface microlayer (SML) and its underlying subsurface water (SSW). Although metal concentrations in the subsurface dissolved fractions vary regionally and globally, it shows a singular metal stoichiometric signature. This work emphasizes the need to study of the SML as unique compartment to improve our understanding of the biogeochemical cycle of trace metals in the surface ocean, especially for metals, such as Pb, Fe and Cu, which are abundant in the SML.

The long-range transport of bioaerosols takes place in the free troposphere and has lately gained a renewed interest in both environmental and health-related disciplines. Sampling free troposphere bioaerosols has been, however, historically challenging and requires of expensive and complex facilities. We analysed different bacterial bioaerosols studies carried out by sequencing of the 16S rRNA gene, available from the literature. The dataset was compared with bacterial bioaerosols present in rain and dry deposition passively collected at highelevation sites in Sierra Nevada along a set of sampling periods lasting 3 years. Up to 65% of OTUs and 82% of the bacterial genera were shared between wet and dry bioaerosols. Interestingly, only Oxalobacteraceae were notably more abundant in wet deposition, with Noviherbaspirillum and Massilia as dominant genera. We demonstrated that the bacterial composition of bioaerosols collected by passive natural deposition at high-elevated mountains were closer to the bacterial microbiome from the free troposphere. Interestingly, the meta-analysis showed a different bacterial composition and community structure in bacterial bioaerosols collected at lowelevated areas, over the open ocean, or during desert dust events. Since the boundary layer can be easily reached in high mountain areas, and the local landscape is surrounded by rocks and meadows, alpine stations are potentially optimal research sites with reduced influence of surface aerosols, minimizing local contaminations. Consequently, sampling alpine bioaerosols could be a good proxy for bioaerosols monitoring, long-range dispersal studies, and the dynamic characterization of the free troposphere microbiome.

Recent developments in the prediction of local aerosol deposition in human lungs are driven by the fast development of computational simulations. Although such simulations provide results in unbeatable resolution, significant differences among distinct methods of calculation emphasize the need for highly precise experimental data in order to specify boundary conditions and for validation purposes. This paper reviews and critically evaluates available methods for the measurement of single and disperse two-phase flows for the study of respiratory airflow and deposition of inhaled particles, performed both in vivo and in replicas of airways. Limitations and possibilities associated with the experimental methods are discussed and aspects of the computational calculations that can be validated are indicated. The review classifies the methods into following categories: 1) point-wise and planar methods for velocimetry in the airways, 2) classic methods for the measurement of the regional distribution of inhaled particles, 3) standard medical imaging methods applicable to the measurement of the regional aerosol distribution and 4) emerging and nonconventional methods. All methods are described, applications in human airways studies are illustrated, and recommendations for the most useful applications of each method are given.

By spraying a high-speed aerosol comprised of a carrier gas and powder particles of metal, alloy, or oxide onto a substrate, a compacted powder is deposited to form a thick film on the substrate. The authors have applied for the first time this aerosol process to the preparation of rechargeable battery electrodes, and have revealed that the process has unique advantages to evaluate anode materials with high capacities. In this review, we introduce highlights of our successful results obtained by the material development of Li-ion battery anodes, and mention a future outlook for the development of the next-generation battery from the viewpoint of the potential of the aerosol process.

Nanoparticles have unique properties that are sought after for the development and improvement of applications. Prerequisite to achieve these applications, methods are required to put the nanoparticles in different patterns and arrangement on a target substrate. In the course of developing an aerosol-based nanoparticle printing system, this work explores the results of different aerosol deposition configurations. The work is based on a spark ablation process that generates an aerosol of argon and copper nanoparticle agglomerates. The deposition configuration deposits the aerosol on a target substrate. Three configurations are explored, one which deposits at subsonic velocities, and two which deposit at sonic velocities. The aim is to find the most favourable deposition conditions for the direct writing of nanoparticle patterns. It is found that a sonic deposition configuration with a low pressure ratio at small substrate distances has the smallest deposit diameter. The configuration allows for the patterning of narrow lines, that consist of two deposition regions: a micro-aggregate region and a nanoparticle region. It was found that the density of these regions is mainly influenced by the process variables of the spark ablation process, and can thus be used to gain a high consistency and well-defined edges., Mechanical Engineering | Micro and Nano Engineering

Recent developments in the prediction of local aerosol deposition in human lungs are driven by the fast development of computational simulations. Although such simulations provide results in unbeatable resolution, significant differences among distinct methods of calculation emphasize the need for highly precise experimental data in order to specify boundary conditions and for validation purposes. This paper reviews and critically evaluates available methods for the measurement of single and disperse two-phase flows for the study of respiratory airflow and deposition of inhaled particles, performed both in vivo and in replicas of airways. Limitations and possibilities associated with the experimental methods are discussed and aspects of the computational calculations that can be validated are indicated. The review classifies the methods into following categories: 1) point-wise and planar methods for velocimetry in the airways, 2) classic methods for the measurement of the regional distribution of inhaled particles, 3) standard medical imaging methods applicable to the measurement of the regional aerosol distribution and 4) emerging and nonconventional methods. All methods are described, applications in human airways studies are illustrated, and recommendations for the most useful applications of each method are given.

Recent developments in the prediction of local aerosol deposition in human lungs are driven by the fast development of computational simulations. Although such simulations provide results in unbeatable resolution, significant differences among distinct methods of calculation emphasize the need for highly precise experimental data in order to specify boundary conditions and for validation purposes. This paper reviews and critically evaluates available methods for the measurement of single and disperse two-phase flows for the study of respiratory airflow and deposition of inhaled particles, performed both in vivo and in replicas of airways. Limitations and possibilities associated with the experimental methods are discussed and aspects of the computational calculations that can be validated are indicated. The review classifies the methods into following categories: 1) point-wise and planar methods for velocimetry in the airways, 2) classic methods for the measurement of the regional distribution of inhaled particles, 3) standard medical imaging methods applicable to the measurement of the regional aerosol distribution and 4) emerging and nonconventional methods. All methods are described, applications in human airways studies are illustrated, and recommendations for the most useful applications of each method are given.

The presence of aerosol deposition hot-spots in human airways presumably contributes to development of various diseases. The overall aerosol deposition in human lungs can be predicted with sufficient accuracy nowadays. However, the prediction of localized aerosol deposition poses arduous challenge, namely in diseased lungs. Numerical simulation is considered to be a promising tool for the successful prediction. Yet, the validation of such simulations is difficult to perform, as not enough experimental data acquired using realistic airway replicas is available. This paper presents a first comparison of localized deposition measurement and simulation performed on the identical realistic geometry. The analysis indicates that both approaches yield similar results for low Reynolds number flows.

A major challenge in nanotechnology is that of determining how to introduce green and sustainable principles when assembling individual nanoscale elements to create working devices. For instance, textile nanofinishing is restricted by the many constraints of traditional pad-dry-cure processes, such as the use of costly chemical precursors to produce nanoparticles (NPs), the high liquid and energy consumption, the production of harmful liquid wastes, and multistep batch operations. By integrating low-cost, scalable, and environmentally benign aerosol processes of the type proposed here into textile nanofinishing, these constraints can be circumvented while leading to a new class of fabrics. The proposed one-step textile nanofinishing process relies on the diffusional deposition of aerosol NPs onto textile fibers. As proof of this concept, we deposit Ag NPs onto a range of textiles and assess their antimicrobial properties for two strains of bacteria (i.e., Staphylococcus aureus and Klebsiella pneumoniae). The measurements show that the logarithmic reduction in bacterial count can get as high as ca. 5.5 (corresponding to a reduction efficiency of 99.96%) when the Ag loading is 1 order of magnitude less (10 ppm; i.e., 10 mg Ag NPs per kg of textile) than that of textiles treated by traditional wet-routes. The antimicrobial activity does not increase in proportion to the Ag content above 10 ppm as a consequence of a "saturation" effect. Such low NP loadings on antimicrobial textiles minimizes the risk to human health (during textile use) and to the ecosystem (after textile disposal), as well as it reduces potential changes in color and texture of the resulting textile products. After three washes, the release of Ag is in the order of 1 wt %, which is comparable to textiles nanofinished with wet routes using binders. Interestingly, the washed textiles exhibit almost no reduction in antimicrobial activity, much as those of as-deposited samples. Considering that a realm, ChemE/Materials for Energy Conversion & Storage, OLD ChemE/Organic Materials and Interfaces, Atmospheric Remote Sensing

The presence of aerosol deposition hot-spots in human airways presumably contributes to development of various diseases. The overall aerosol deposition in human lungs can be predicted with sufficient accuracy nowadays. However, the prediction of localized aerosol deposition poses arduous challenge, namely in diseased lungs. Numerical simulation is considered to be a promising tool for the successful prediction. Yet, the validation of such simulations is difficult to perform, as not enough experimental data acquired using realistic airway replicas is available. This paper presents a first comparison of localized deposition measurement and simulation performed on the identical realistic geometry. The analysis indicates that both approaches yield similar results for low Reynolds number flows.

The presence of aerosol deposition hot-spots in human airways presumably contributes to development of various diseases. The overall aerosol deposition in human lungs can be predicted with sufficient accuracy nowadays. However, the prediction of localized aerosol deposition poses arduous challenge, namely in diseased lungs. Numerical simulation is considered to be a promising tool for the successful prediction. Yet, the validation of such simulations is difficult to perform, as not enough experimental data acquired using realistic airway replicas is available. This paper presents a first comparison of localized deposition measurement and simulation performed on the identical realistic geometry. The analysis indicates that both approaches yield similar results for low Reynolds number flows.

The present article is intended to study the deposition mechanisms of bioactive hydroxyapatite (HA) particles by means of Cold Gas Spraying (CGS). A comparison of the deposition on two different substrates (Ti6Al4V and Al7075T6) and different particle sizes is presented. Although this is a more specific deposition technique for ductile materials, it is here shown that, in certain conditions, ceramic deposition is possible despite the inherent low ductility. The resulting internal structure and the features at the particle-substrate interface are discussed in view of Transmission Electron Microscopy examinations of a Focused Ion Beam lift-out prepared sample. Mainly, under shock compressive loading, the porous sintered powder proceeds through pore collapse, fragmentation and densification as well as grain refinement. The process is described through different plastic mechanisms in ceramics. This opens a new alternative route to produce nanocrystalline HA coatings through a cost-effective process.

[EN] Aeolian inputs of organic and inorganic nutrients to the ocean are important as they can enhance biological production in surface waters, especially in oligotrophic areas like the Mediterranean. The Mediterranean littoral is particularly exposed to both anthropogenic and Saharan aerosol depositions on a more or less regular basis. During the last few decades experimental studies have been devoted to examining the effect of inorganic nutrient inputs from dust on microbial activity. In this study, we performed experiments at two different locations of the NW Mediterranean, where we evaluated the changes in the quality and quantity of dissolved organic matter due to atmospheric inputs of different origin (Saharan and anthropogenic) and its subsequent transformations mediated by microbial activities. In both experiments the humic-like and protein-like substances, and the fluorescence quantum yield increased after addition. In general, these changes in the quality of dissolved organic matter did not significantly affect the prokaryotes. The recalcitrant character of the fluorescent dissolved organic matter (FDOM) associated with aerosols was confirmed, as we found negligible utilization of chromophoric compounds over the experimental period. We framed these experiments within a two-year time series data set of atmospheric deposition and coastal surface water analyses. These observations showed that both Saharan and anthropogenic inputs induced changes in the quality of organic matter, increasing the proportion of FDOM substances. This increase was larger during Saharan dust events than in the absence of Saharan influence, [ES] Los aportes atmosféricos de nutrientes orgánicos e inorgánicos al océano son importantes ya que pueden aumentar la producción biológica en aguas superficiales, especialmente en las zonas oligotróficas como el Mediterráneo. El litoral del Mediterráneo está particularmente expuesto a aportes de origen antropogénico y a deposiciones de polvo sahariano de forma más o menos regular. Durante las últimas décadas los estudios experimentales se han dedicado, sobre todo, a examinar el efecto de la entrada de nutrientes inorgánicos atmosféricos sobre la actividad microbiana. En este estudio, se realizaron experimentos con comunidades microbianas procedentes de dos zonas del Mediterráneo noroccidental. Se evaluaron los cambios en la calidad y cantidad de la materia orgánica disuelta debido a aportes atmosféricos de distinto origen y sus posteriores transformaciones mediadas por actividades microbianas. En ambos experimentos las sustancias orgánicas fluorescentes y el rendimiento cuántico de fluorescencia aumentaron después de la adición de material atmosférico. En general, estos cambios en la calidad de la materia orgánica no afectaron significativamente a los organismos procariotas. El carácter recalcitrante de la materia orgánica disuelta fluorescente (FDOM) contenida en los aerosoles se confirmó ya que la utilización de compuestos cromóforos durante el período experimental fue insignificante. Los resultados obtenidos se contextualizan en relación con una serie temporal de dos años de datos adquiridos de deposición atmosférica y análisis de agua superficial costera. La variabilidad temporal de estas dos variables mostró que tanto los aportes saharianos como antropogénicos provocaron cambios en la calidad de la materia orgánica disuelta en aguas superficiales, incrementando la fracción fluorescente. Éste aumento resultó ser mayor durante eventos de polvo sahariano que en ausencia de ellos

In this research, we clarify the aerosol dynamics during thin film formation by using the Aerosol Deposition (AD) technique under the microgravity conditions. The aerosol deposition technique is useful for making thin film of ceramics materials. We are now trying this technique to make thin film of thermally unstable materials, such as clathrate compounds and/or amorphous materials. However, it is difficult to make homogeneously the aerosol of these materials in the terrestrial conditions, because in the terrestrial conditions the fine particles of these materials are settled down below the chamber during making its aerosol. Thus, in the microgravity conditions, we hope to make homogeneously aerosol for good quality of thin film by the aerosol deposition technique. For this purpose, we developed the system of AD technique under microgravity conditions during parabolic flight by airplane. Using the system, we succeeded to make thin films of (Pb (Ti, Zr) O3)(PZT(Lead Zirconate Titanate)) by the AD technique under microgravity conditions. From present results, we discussed about the relationship between aerosol flow and deposition conditions under microgravity conditions.

It seems to be very convenient to receive a medicine by inhalation instead of injection. Unfortunately transport of particles and targeted delivery of a drug in human respiratory airways is very complicated task. Therefore we carried out experiments and tested different methods for evaluation of particle deposition in a model of human lungs. The model included respiratory airways from oral cavity to 7th generation of branching. Particles were dispersed by TSI Small-scale Powder Disperser 3433 and delivered to the model. The model was disassembled into segments after the deposition of the particles and local deposition was measured. Two methods were used to analyse the samples, fluorescence spectroscopy and optical microscopy. The first method was based on measuring the intensity of luminescence, which represented the particle deposition. The second method used the optical microscope with phase-contrast objective. A dispersion of isopropanol and particles was filtrated using a vacuum filtration unit, a filter was placed on glass slide and made transparent. The particles on the filter were counted manually and the deposition was calculated afterwards. The results of the methods were compared and both methods proved to be useful., Podávání léků inhalací místo injekční cestou je velice pohodlné. Avšak transport aerosolů a jeho cílená dodávka v lidských dýchacích cestách je velice komplikovaný problém. Proto bylo provedeno několik depozičních experimentů a odzkoušeno několik metod pro vyhodnocení depozice v modelu lidských plic. Model obsahoval dýchací cesty od ústní dutiny až po 7. generaci větvení. Částice byly dispergovány pomocí TSI SSPD 3433 a aplikovány do modelu. Po ukončení depozice byl model rozebrán a depozice v jednotlivých částech byla analyzována. Pro vyhodnocení byly použity 2 metody, fluorescenční spektroskopie a optická mikroskopie. První metoda využívá měření intenzity fluorescence částic, jejíž velikost určuje míru depozice. Druhá metoda využívá optické mikroskopie ve spojení s fázovým kontrastem. Výsledky obou metod byly porovnány a metody byly vyhodnoceny jako použitelné.

It seems to be very convenient to receive a medicine by inhalation instead of injection. Unfortunately transport of particles and targeted delivery of a drug in human respiratory airways is very complicated task. Therefore we carried out experiments and tested different methods for evaluation of particle deposition in a model of human lungs. The model included respiratory airways from oral cavity to 7th generation of branching. Particles were dispersed by TSI Small-scale Powder Disperser 3433 and delivered to the model. The model was disassembled into segments after the deposition of the particles and local deposition was measured. Two methods were used to analyse the samples, fluorescence spectroscopy and optical microscopy. The first method was based on measuring the intensity of luminescence, which represented the particle deposition. The second method used the optical microscope with phase-contrast objective. A dispersion of isopropanol and particles was filtrated using a vacuum filtration unit, a filter was placed on glass slide and made transparent. The particles on the filter were counted manually and the deposition was calculated afterwards. The results of the methods were compared and both methods proved to be useful., Podávání léků inhalací místo injekční cestou je velice pohodlné. Avšak transport aerosolů a jeho cílená dodávka v lidských dýchacích cestách je velice komplikovaný problém. Proto bylo provedeno několik depozičních experimentů a odzkoušeno několik metod pro vyhodnocení depozice v modelu lidských plic. Model obsahoval dýchací cesty od ústní dutiny až po 7. generaci větvení. Částice byly dispergovány pomocí TSI SSPD 3433 a aplikovány do modelu. Po ukončení depozice byl model rozebrán a depozice v jednotlivých částech byla analyzována. Pro vyhodnocení byly použity 2 metody, fluorescenční spektroskopie a optická mikroskopie. První metoda využívá měření intenzity fluorescence částic, jejíž velikost určuje míru depozice. Druhá metoda využívá optické mikroskopie ve spojení s fázovým kontrastem. Výsledky obou metod byly porovnány a metody byly vyhodnoceny jako použitelné.

It seems to be very convenient to receive a medicine by inhalation instead of injection. Unfortunately transport of particles and targeted delivery of a drug in human respiratory airways is very complicated task. Therefore we carried out experiments and tested different methods for evaluation of particle deposition in a model of human lungs. The model included respiratory airways from oral cavity to 7th generation of branching. Particles were dispersed by TSI Small-scale Powder Disperser 3433 and delivered to the model. The model was disassembled into segments after the deposition of the particles and local deposition was measured. Two methods were used to analyse the samples, fluorescence spectroscopy and optical microscopy. The first method was based on measuring the intensity of luminescence, which represented the particle deposition. The second method used the optical microscope with phase-contrast objective. A dispersion of isopropanol and particles was filtrated using a vacuum filtration unit, a filter was placed on glass slide and made transparent. The particles on the filter were counted manually and the deposition was calculated afterwards. The results of the methods were compared and both methods proved to be useful., Podávání léků inhalací místo injekční cestou je velice pohodlné. Avšak transport aerosolů a jeho cílená dodávka v lidských dýchacích cestách je velice komplikovaný problém. Proto bylo provedeno několik depozičních experimentů a odzkoušeno několik metod pro vyhodnocení depozice v modelu lidských plic. Model obsahoval dýchací cesty od ústní dutiny až po 7. generaci větvení. Částice byly dispergovány pomocí TSI SSPD 3433 a aplikovány do modelu. Po ukončení depozice byl model rozebrán a depozice v jednotlivých částech byla analyzována. Pro vyhodnocení byly použity 2 metody, fluorescenční spektroskopie a optická mikroskopie. První metoda využívá měření intenzity fluorescence částic, jejíž velikost určuje míru depozice. Druhá metoda využívá optické mikroskopie ve spojení s fázovým kontrastem. Výsledky obou metod byly porovnány a metody byly vyhodnoceny jako použitelné.

It seems to be very convenient to receive a medicine by inhalation instead of injection. Unfortunately transport of particles and targeted delivery of a drug in human respiratory airways is very complicated task. Therefore we carried out experiments and tested different methods for evaluation of particle deposition in a model of human lungs. The model included respiratory airways from oral cavity to 7th generation of branching. Particles were dispersed by TSI Small-scale Powder Disperser 3433 and delivered to the model. The model was disassembled into segments after the deposition of the particles and local deposition was measured. Two methods were used to analyse the samples, fluorescence spectroscopy and optical microscopy. The first method was based on measuring the intensity of luminescence, which represented the particle deposition. The second method used the optical microscope with phase-contrast objective. A dispersion of isopropanol and particles was filtrated using a vacuum filtration unit, a filter was placed on glass slide and made transparent. The particles on the filter were counted manually and the deposition was calculated afterwards. The results of the methods were compared and both methods proved to be useful., Podávání léků inhalací místo injekční cestou je velice pohodlné. Avšak transport aerosolů a jeho cílená dodávka v lidských dýchacích cestách je velice komplikovaný problém. Proto bylo provedeno několik depozičních experimentů a odzkoušeno několik metod pro vyhodnocení depozice v modelu lidských plic. Model obsahoval dýchací cesty od ústní dutiny až po 7. generaci větvení. Částice byly dispergovány pomocí TSI SSPD 3433 a aplikovány do modelu. Po ukončení depozice byl model rozebrán a depozice v jednotlivých částech byla analyzována. Pro vyhodnocení byly použity 2 metody, fluorescenční spektroskopie a optická mikroskopie. První metoda využívá měření intenzity fluorescence částic, jejíž velikost určuje míru depozice. Druhá metoda využívá optické mikroskopie ve spojení s fázovým kontrastem. Výsledky obou metod byly porovnány a metody byly vyhodnoceny jako použitelné.

It seems to be very convenient to receive a medicine by inhalation instead of injection. Unfortunately transport of particles and targeted delivery of a drug in human respiratory airways is very complicated task. Therefore we carried out experiments and tested different methods for evaluation of particle deposition in a model of human lungs. The model included respiratory airways from oral cavity to 7th generation of branching. Particles were dispersed by TSI Small-scale Powder Disperser 3433 and delivered to the model. The model was disassembled into segments after the deposition of the particles and local deposition was measured. Two methods were used to analyse the samples, fluorescence spectroscopy and optical microscopy. The first method was based on measuring the intensity of luminescence, which represented the particle deposition. The second method used the optical microscope with phase-contrast objective. A dispersion of isopropanol and particles was filtrated using a vacuum filtration unit, a filter was placed on glass slide and made transparent. The particles on the filter were counted manually and the deposition was calculated afterwards. The results of the methods were compared and both methods proved to be useful., Podávání léků inhalací místo injekční cestou je velice pohodlné. Avšak transport aerosolů a jeho cílená dodávka v lidských dýchacích cestách je velice komplikovaný problém. Proto bylo provedeno několik depozičních experimentů a odzkoušeno několik metod pro vyhodnocení depozice v modelu lidských plic. Model obsahoval dýchací cesty od ústní dutiny až po 7. generaci větvení. Částice byly dispergovány pomocí TSI SSPD 3433 a aplikovány do modelu. Po ukončení depozice byl model rozebrán a depozice v jednotlivých částech byla analyzována. Pro vyhodnocení byly použity 2 metody, fluorescenční spektroskopie a optická mikroskopie. První metoda využívá měření intenzity fluorescence částic, jejíž velikost určuje míru depozice. Druhá metoda využívá optické mikroskopie ve spojení s fázovým kontrastem. Výsledky obou metod byly porovnány a metody byly vyhodnoceny jako použitelné.

Positron Emission Tomography (PET) is a convenient method for measurement of aerosol deposition in complex models of lungs. It allows not only the evaluation of regional deposition characteristics but also precisely detects deposition hot spots. The method is based on a detection of a pair of annihilation photons moving in opposite directions as a result of positron – electron interaction after the positron emission decay of a suitable radioisotope. Liquid di(2-ethylhexyl) sebacate (DEHS) particles tagged with fluorine-18 as a radioactive tracer were generated by condensation monodisperse aerosol generator. Aerosol deposition was measured for three different inhalation flowrates and for two sizes of particles. Combination of PET with Computed Tomography (CT) in one device allowed precise localisation of particular segments of the model. The results proved correlation of deposition efficiency with Stokes number, which means that the main deposition mechanism is inertial impaction. As a next task the methodology for tagging the solid aerosol particles with radioactive tracer will be developed and deposition of porous and fiber aerosols will be measured., Pozitronová emisní tomografie (PET) je vhodná metoda pro měření depozice aerosolu ve složitých modelech plic. Umožňuje jak určení regionálních depozičních charakteristik, tak i lokalizaci depozičních ohnisek. Metoda je založena na detekci páru anihilačních fotonů, které se pohybují v opačných směrech jako výsledek interakce elektronu a pozitronu po emisi pozitronů z vhodného radioizotopu. Depozice aerosolu byla měřena pro tři režimy a dvě velikosti částic. Výsledky prokázaly korelaci mezi depoziční účinností a Stokesovým číslem, což znamená, že v měřených režimech je dominantním depozičním mechanismem setrvačný impakt.

Positron Emission Tomography (PET) is a convenient method for measurement of aerosol deposition in complex models of lungs. It allows not only the evaluation of regional deposition characteristics but also precisely detects deposition hot spots. The method is based on a detection of a pair of annihilation photons moving in opposite directions as a result of positron – electron interaction after the positron emission decay of a suitable radioisotope. Liquid di(2-ethylhexyl) sebacate (DEHS) particles tagged with fluorine-18 as a radioactive tracer were generated by condensation monodisperse aerosol generator. Aerosol deposition was measured for three different inhalation flowrates and for two sizes of particles. Combination of PET with Computed Tomography (CT) in one device allowed precise localisation of particular segments of the model. The results proved correlation of deposition efficiency with Stokes number, which means that the main deposition mechanism is inertial impaction. As a next task the methodology for tagging the solid aerosol particles with radioactive tracer will be developed and deposition of porous and fiber aerosols will be measured., Pozitronová emisní tomografie (PET) je vhodná metoda pro měření depozice aerosolu ve složitých modelech plic. Umožňuje jak určení regionálních depozičních charakteristik, tak i lokalizaci depozičních ohnisek. Metoda je založena na detekci páru anihilačních fotonů, které se pohybují v opačných směrech jako výsledek interakce elektronu a pozitronu po emisi pozitronů z vhodného radioizotopu. Depozice aerosolu byla měřena pro tři režimy a dvě velikosti částic. Výsledky prokázaly korelaci mezi depoziční účinností a Stokesovým číslem, což znamená, že v měřených režimech je dominantním depozičním mechanismem setrvačný impakt.

Positron Emission Tomography (PET) is a convenient method for measurement of aerosol deposition in complex models of lungs. It allows not only the evaluation of regional deposition characteristics but also precisely detects deposition hot spots. The method is based on a detection of a pair of annihilation photons moving in opposite directions as a result of positron – electron interaction after the positron emission decay of a suitable radioisotope. Liquid di(2-ethylhexyl) sebacate (DEHS) particles tagged with fluorine-18 as a radioactive tracer were generated by condensation monodisperse aerosol generator. Aerosol deposition was measured for three different inhalation flowrates and for two sizes of particles. Combination of PET with Computed Tomography (CT) in one device allowed precise localisation of particular segments of the model. The results proved correlation of deposition efficiency with Stokes number, which means that the main deposition mechanism is inertial impaction. As a next task the methodology for tagging the solid aerosol particles with radioactive tracer will be developed and deposition of porous and fiber aerosols will be measured., Pozitronová emisní tomografie (PET) je vhodná metoda pro měření depozice aerosolu ve složitých modelech plic. Umožňuje jak určení regionálních depozičních charakteristik, tak i lokalizaci depozičních ohnisek. Metoda je založena na detekci páru anihilačních fotonů, které se pohybují v opačných směrech jako výsledek interakce elektronu a pozitronu po emisi pozitronů z vhodného radioizotopu. Depozice aerosolu byla měřena pro tři režimy a dvě velikosti částic. Výsledky prokázaly korelaci mezi depoziční účinností a Stokesovým číslem, což znamená, že v měřených režimech je dominantním depozičním mechanismem setrvačný impakt.

Growing concern about knowledge of aerosol transport in human lungs is caused by great potential of use of inhaled pharmaceuticals. Second substantial motive for the research is an effort to minimize adverse effects of particular matter emitted by traffic and industry on human health. We created model geometry of human lungs to 7th generation of branching. This model geometry was used for fabrication of two physical models. The first one is made from thin walled transparent silicone and it allows a measurement of velocity and size of aerosol particles by Phase Doppler Anemometry (PDA). The second one is fabricated by stereolithographic method and it is designed for aerosol deposition measurements. We provided a series of measurements of aerosol transport in the transparent model and we ascertained remarkable phenomena linked with lung flow. The results are presented in brief. To gather how this phenomena affects aerosol deposition in human lungs we used the second model and we developed a technique for deposition fraction and deposition efficiency assessment. The results confirmed that non-symmetric and complicated shape of human airways essentially affects transport and deposition of aerosol. The research will now focus on deeper insight in aerosol deposition., Rostoucí zájem o znalost transportu aerosolu v lidských plicích je zapříčiněn velkým potenciálem užití inhalovaných farmaceutik. Druhým podstatným motivem výzkumu je snaha minimalizovat škodlivé účinky aerosolů emitovaných průmyslem a dopravou. Vytvořili jsme modelovou geometrii plic do 7. generace, z níž vznikly dva modely. První je opticky transparentní a umožňuje studium transportu aerosolu pomocí optických měřicích metod, druhý je segmentový a umožňuje měření lokální depozice aerosolu. V článku jsou v krátkosti prezentovány první výsledky.

Within the framework of aerosol deposition to vegetation we present a specially designed leaf wash-off method used in a wind-tunnel based study, where leaves of Quercus robur L. were exposed to NaCl aerosols. We summarise the principles and illustrate the method for two types of substances, the chloride ion and the sodium ion, and for two levels of aerosol exposure prior to leaf washing. On the average, in the low-exposure experiments (S1), the 1st (2nd) wash-off step provided 90% (96%) of the amount of Cl− on the leaves. In the high-exposure experiments (S2) the corresponding values were 96% and 99%. For sodium, the general dynamics resembles that of chloride, but the amounts washed off were, in both series, on the average below what would be expected if the equivalent ratio in the tunnel aerosol were to be preserved. Na+ showed adsorption and/or absorption at the leaf surfaces. The difference between the mean values of the amounts of chloride and of sodium washed off in S1 was not statistically significant, the mean Na+ to Cl− difference as a fraction of Cl− being minus 18%±27%; corresponding values for S2 were minus 16%±9%, however (p<0.05). In the latter case, 101±57 μequiv Na+ per m2 of leaf area were missing for the equivalent relationship 1:1 with Cl− to be met. Although uncertainties are thus large, this indicates the magnitude of the Na+-retention. The method is suitable not only for chloride, an inexpensive and easy-to-handle tracer, but also for sodium under exposure at high aerosol concentrations. Our findings will help design further studies of aerosol/forest interactions.

Although there is a modest body of literature on the absorption of inhaled pharmaceuticals by normal lungs and some limited information from diseased lungs, there is still a surprising lack of mechanistic knowledge about the details of the processes involved. Where are molecules absorbed, what mechanisms are involved, how well are different lung regions penetrated, what are the determinants of metabolism and dissolution, and how best can one retard the clearance of molecules deposited in the lung or induce intracellular uptake by lung cells? Some general principles are evident: (1) small hydrophobic molecules are absorbed very fast (within tens of seconds) usually with little metabolism; (2) small hydrophilic molecules are absorbed fast (within tens of minutes), again with minimal metabolism; (3) very low water solubility of the drug can retard absorption; (4) peptides are rapidly absorbed but are significantly metabolized unless chemically protected against peptidases; (5) larger proteins are more slowly absorbed with variable bioavailabilities; and 6) insulin seems to be best absorbed distally in the lungs while certain antibodies appear to be preferentially absorbed in the upper airways. For local lung disease applications, and some systemic applications as well, many small molecules are absorbed much too fast for convenient and effective therapies. For systemic delivery of peptides and proteins, absorption may sometimes be too fast. Bioavailabilities are often too low for cost-effective and reliable treatments. A better understanding of the determinants of pulmonary drug dissolution, absorption, metabolism, and how to target specific regions and/or cells in the lung will enable safer and more effective inhaled medicines in the future.

Growing concern about knowledge of aerosol transport in human lungs is caused by great potential of use of inhaled pharmaceuticals. Second substantial motive for the research is an effort to minimize adverse effects of particular matter emitted by traffic and industry on human health. We created model geometry of human lungs to 7th generation of branching. This model geometry was used for fabrication of two physical models. The first one is made from thin walled transparent silicone and it allows a measurement of velocity and size of aerosol particles by Phase Doppler Anemometry (PDA). The second one is fabricated by stereolithographic method and it is designed for aerosol deposition measurements. We provided a series of measurements of aerosol transport in the transparent model and we ascertained remarkable phenomena linked with lung flow. The results are presented in brief. To gather how this phenomena affects aerosol deposition in human lungs we used the second model and we developed a technique for deposition fraction and deposition efficiency assessment. The results confirmed that non-symmetric and complicated shape of human airways essentially affects transport and deposition of aerosol. The research will now focus on deeper insight in aerosol deposition., Rostoucí zájem o znalost transportu aerosolu v lidských plicích je zapříčiněn velkým potenciálem užití inhalovaných farmaceutik. Druhým podstatným motivem výzkumu je snaha minimalizovat škodlivé účinky aerosolů emitovaných průmyslem a dopravou. Vytvořili jsme modelovou geometrii plic do 7. generace, z níž vznikly dva modely. První je opticky transparentní a umožňuje studium transportu aerosolu pomocí optických měřicích metod, druhý je segmentový a umožňuje měření lokální depozice aerosolu. V článku jsou v krátkosti prezentovány první výsledky.

Growing concern about knowledge of aerosol transport in human lungs is caused by great potential of use of inhaled pharmaceuticals. Second substantial motive for the research is an effort to minimize adverse effects of particular matter emitted by traffic and industry on human health. We created model geometry of human lungs to 7th generation of branching. This model geometry was used for fabrication of two physical models. The first one is made from thin walled transparent silicone and it allows a measurement of velocity and size of aerosol particles by Phase Doppler Anemometry (PDA). The second one is fabricated by stereolithographic method and it is designed for aerosol deposition measurements. We provided a series of measurements of aerosol transport in the transparent model and we ascertained remarkable phenomena linked with lung flow. The results are presented in brief. To gather how this phenomena affects aerosol deposition in human lungs we used the second model and we developed a technique for deposition fraction and deposition efficiency assessment. The results confirmed that non-symmetric and complicated shape of human airways essentially affects transport and deposition of aerosol. The research will now focus on deeper insight in aerosol deposition., Rostoucí zájem o znalost transportu aerosolu v lidských plicích je zapříčiněn velkým potenciálem užití inhalovaných farmaceutik. Druhým podstatným motivem výzkumu je snaha minimalizovat škodlivé účinky aerosolů emitovaných průmyslem a dopravou. Vytvořili jsme modelovou geometrii plic do 7. generace, z níž vznikly dva modely. První je opticky transparentní a umožňuje studium transportu aerosolu pomocí optických měřicích metod, druhý je segmentový a umožňuje měření lokální depozice aerosolu. V článku jsou v krátkosti prezentovány první výsledky.

Growing concern about knowledge of aerosol transport in human lungs is caused by great potential of use of inhaled pharmaceuticals. Second substantial motive for the research is an effort to minimize adverse effects of particular matter emitted by traffic and industry on human health. We created model geometry of human lungs to 7th generation of branching. This model geometry was used for fabrication of two physical models. The first one is made from thin walled transparent silicone and it allows a measurement of velocity and size of aerosol particles by Phase Doppler Anemometry (PDA). The second one is fabricated by stereolithographic method and it is designed for aerosol deposition measurements. We provided a series of measurements of aerosol transport in the transparent model and we ascertained remarkable phenomena linked with lung flow. The results are presented in brief. To gather how this phenomena affects aerosol deposition in human lungs we used the second model and we developed a technique for deposition fraction and deposition efficiency assessment. The results confirmed that non-symmetric and complicated shape of human airways essentially affects transport and deposition of aerosol. The research will now focus on deeper insight in aerosol deposition., Rostoucí zájem o znalost transportu aerosolu v lidských plicích je zapříčiněn velkým potenciálem užití inhalovaných farmaceutik. Druhým podstatným motivem výzkumu je snaha minimalizovat škodlivé účinky aerosolů emitovaných průmyslem a dopravou. Vytvořili jsme modelovou geometrii plic do 7. generace, z níž vznikly dva modely. První je opticky transparentní a umožňuje studium transportu aerosolu pomocí optických měřicích metod, druhý je segmentový a umožňuje měření lokální depozice aerosolu. V článku jsou v krátkosti prezentovány první výsledky.

In this work we optimized conditions for aerosol deposition of homogeneous, nano-grained, smooth Ba0.8Sr0.2TiO3 thin films. Investigation involved optimization of deposition parameters, namely deposition time and temperature for different substrates. Solutions were prepared from titanium isopropoxide, strontium acetate and barium acetate. Films were deposited on Si (1 0 0) or Si covered by platinum (Pt (1 1 1) /Ti/SiO2/Si). Investigation showed that the best films were obtained at substrate temperature of 85 degrees C. After deposition films were slowly heated up to 650 degrees C, annealed for 30 min, and slowly cooled. Grain size of BST films deposited on Si substrate were in the range 40-70 nm, depending on deposition conditions, while the same films deposited on Pt substrates showed mean grain size in the range 35-50 nm. Films deposited under optimal conditions were very homogeneous, crack-free, and smooth with rms roughness lower than 4 nm for both substrates.

Research Doctorate - Doctor of Philosophy (PhD), This work reports the deposition onto high voltage insulators and correlation to atmospheric corrosivity measurement. This work includes corrosion studies at 15 sites in New Zealand (1,816 tests) for in excess of 12 months, and co-operative research in South Africa. In addition, to confirm the relevance and transportability of this proposed model, a review of the published international data on deposition rates on insulators was conducted. It was noted that the deposition rate of airborne pollutants onto a surface is dependent upon the true surface area facing the wind and the aerodynamic properties of the surface. Such is the effect that surfaces with minimal exposure to the wind such as horizontal plates, have been shown to be poor collectors of deposits while vertical plates are more efficient, followed by high voltage glass insulators, the ISO9223 salt candle, and the largest collector is the Direct Dust Deposit Gauge. This study found that the ISO9223 wet salt candle and the average annual deposition rate on the High Voltage Glass insulator bottom surface (unenergized) provided relatively similar deposition results. The deposition onto insulator surfaces may be a more relevant method as it replicates deposition on large surfaces. This Equivalent Salt Dry Deposition (ESDD) method for HV insulators is an all inclusive measure of the airborne pollutants deposition rate and converts the total deposited material into a single value equivalent to that of salt, even though the deposit may consist of sulphur, marine salts, nitrates, and other conductive pollutants. The measured deposition rate on the sheltered insulator bottoms at 85 sites around the world predicted 87% of the ISO corrosivity categories (based on zinc corrosion) for these sites. Results from equatorial Asia appear to be non-compliant and warrant further investigation. The ESDD values are now being quoted from around the world, by electrical engineers who use the recently revised CIGRE methodology, to d

Monthly or more frequent measures of internal and external nitrogen and phosphorus (NP) loading to Flathead Lake, Montana, in relation to biotic response variables and attendant interactive effects associated with invasion of a nonnative amphipod, Mysis relicta were made during 1977-2004. Trends and interactions were evaluated for statistical significance using Bayesian models against null hypotheses of no effects. Aerosol deposition contributed 10.1% and 7.0% of the total annual NP load; nitrate and ammonium increased and soluble reactive phosphorus declined over the period of record. Deposition was highest during thermal inversions that entrained smoke and dust. Riverine nitrate increased and ammonium and SRP decreased. Increasing trends were coherent with increasing urbanization and forest disturbance. However, contribution of sewage treatment facilities to annual TP load decreased from 11% to 3% following improved nutrient removal technologies. Increasing primary productivity per unit chlorophyll (PP/chla) and decreasing hypolimnetic oxygen concentrations were coherent with the trends in NP loading and therefore indicative of human influences. The lake remains oligotrophic with productivity limited by availability of labile NP, although worrisome blooms of algae, including Anabaena flos-aquae, occurred several times during the period of record. Catastrophic food web change was clearly associated with the establishment of Mysis relicta. Mysids exploded to 129 m2 in 1984-86. Their intense foraging on zooplankton caused an 83% reduction in the biomass of large species. Kokanee salmon, also a zooplankton feeder, were extirpated, whereas lake trout increased from 0.09 before to 1.7 cpue after Mysis in standardized gill net catches. Lake trout expansion and zooplankton changes corresponded with an 80% decline in native salmonid fishes. Mysids declined rapidly with increasing profundal fish predation during 1987-88 and then stabilized around 40 m2. A Bayesian analysis

The deposition of unipolarly charged aerosol particles by simultaneous Brownian diffusion and electrostatic dispersion (spacecharge) in laminar flow tubes has been modelled in two different ways. In the first approach, the rigorous transport equation has been solved numerically under the restriction of negligible axial components of the particle Brownian motion and of the space-charge electric field. The thus calculated theoretical penetrations agree satisfactorily with the experimental results obtained for air ions. Second, the system has also been modelled from a phenomenological point of view, based on the fact that deposition by diffusion and space-charge follows first- and second-order kinetics, respectively. The latter approach yields a simple and practical equation correlating particle penetration with tube geometry, aerosol flow rate, and particle mobility and concentration.

Strain- and variety-related differences in responses of mice have been reported for a variety of inhaled particulate and gaseous materials. It is important to understand the potential contributions to such responses of differences in delivered doses to the respiratory tract as well as differences in biochemical processes. Deposition doses of inhaled particles are influenced by several factors, including airway anatomy, ventilation, and particle characteristics. Tracheobronchial airway morphometry for airway generations 1-6 of the BALB/c mouse was generated using replica lung casts prepared in situ. Measurements were performed on two groups: control and ovalbumin-sensitized male BALB/c mice. These measurements were compared with previously published airway morphometry of male B6C3F(1) mice. Sensitization did not significantly change measured airway dimensions in the BALB/c mouse. However, the two mouse varieties had significant differences in airway anatomy. The differences found in airway anatomy between mouse varieties correlated with differences in body length and chest circumference. Particle deposition predictions for both varieties of mice were performed for unit density spherical particles from 0.1 to 10 microm in diameter at two ventilation rates using a published aerosol dosimetry computer code. Particle deposition in the proximal tracheobronchial tree ranged up to 3 times greater for the BALB/c mouse for a 2 microm particle diameter and high ventilation rate. These differences in predicted particle deposition suggest that observed strain and variety differences in response to inhaled particulate matter may be in part due to differences in delivered doses to the respiratory tract.

SCOPUS: ar.j, info:eu-repo/semantics/published

SCOPUS: ar.j, info:eu-repo/semantics/published

One-dimensional transport models (trumpet model and multi-branch-point model) derived from those developed to study gas transport and mixing in the lung are used to simulate aerosol deposition as a function of particle diameter and aerosol dispersion of inhaled bolus in human lungs. In agreement with previous studies, aerosol deposition is satisfactorily simulated by the different models. However, the differences between simulations and experiments of aerosol bolus dispersion suggest that current models are not realistic. This is probably due to the intrinsic limitations of the one- dimensional models to describe aerosol transport in the lung periphery. We show that future model analyses can probably use a symmetric acinar structure like the classic Weibel model of the lung but that multidimensional particle transport equations are required. Furthermore, a rigorous description of aerosol dispersion in the oral-laryngeal path is also needed., SCOPUS: ar.j, info:eu-repo/semantics/published

Vdechovaný aerosol má značný vliv na zdraví každého člověka. Pochopení mechanismů transportu a depozice aerosolu v lidských plicích je nutnou podmínkou jak pro lepší ochranu před toxickými účinky škodlivých částic, tak zejména pro efektivní použití inhalovaných terapeutických aerosolů. Smyslem této dizertační práce proto bylo získat nové poznatky v této oblasti na základě in vitro prováděných experimentů. Pro měření transportu aerosolu byla zvolena fázová Dopplerovská anemometrie, kterou byla měřena současně rychlost i velikost částic. Výsledky byly zpracovány metodami statistické a frekvenční analýzy. Depozice sférických aerosolových částic byla měřena pozitronovou emisní tomografií, fázově kontrastní mikroskopie kombinovaná s automatickou analýzou obrazů byla využita pro měření depozice vláknových částic. Všechny experimenty byly provedeny na fyzických modelech plic vytvořených na základě reálné geometrie. Výsledkem práce jsou poznatky o charakteristikách proudění, přechodu z laminárního do turbulentního režimu, vlivu režimu dýchání a velikosti částic na transport aerosolu a rozložení depozice aerosolu při různých režimech. Porovnáním depozice na realistickém a semirealistickém modelu s válcovými stěnami byl zjištěn zásadní vliv realistické ústní dutiny. Získané poznatky slouží nejen k rozšíření současných znalostí o chování aerosolu v plicích, ale mohou být použity i pro validaci numerických simulací., Human health is significantly influenced by inhaled aerosols. Insight to the aerosol transport and deposition mechanisms is a prerequisite for both, toxicological protection against harmful particles and efficient application of inhaled therapeutic aerosols. The purpose of this doctoral thesis was to gain new knowledge of this topic on the basis of in vitro measurements. Phase-Doppler Anemometry was chosen for aerosol transport measurement, for it allows simultaneous measurement of particle size and velocity. Results were processed by means of statistical methods and frequency analysis. Deposition of spherical aerosol particles was measured by Positron Emission Tomography, while deposition of fibrous aerosol was measured by Phase-Contrast Microscopy combined with automated image analysis. All experiments were performed on physical models created on the basis of the real lung geometry. New knowledge of flow characteristics, transition from laminar to turbulent flow, effect of breathing pattern or particle size on aerosol transport and deposition in human lungs are outcomes of this work. Significant effect of the oral cavity was ascertained due to comparison of aerosol deposition in realistic and semi-realistic model with cylindrical smooth walls. Acquired data not merely extended our knowledge of aerosol behavior in lungs but it can also be used for validation of numerical simulations.

Tato bakalářská práce se zabývá modely plic pro měření depozice a počítačovými simulacemi usazování inhalovaných částic. Byla provedena rešerše nejnovějších poznatků. Uvedeny jsou i základy anatomie a fyziologie lidského dýchacího systému. Bylo provedeno měření depozice chitosanových částic fluorometrickou metodou na modelu plic, vyhodnocení výsledků a srovnání s odbornou literaturou., This bachelor thesis deals with lung models for deposition measurement and computer simulations of inhaled particle deposition. The latest findings were reviewed. The basics of human respiratory anatomy and physiology are also presented. The measurement of chitosan particle deposition was performed by a fluorometric method on the lung model, results were evaluated and compared with literature.

Jednou z možných cest léčby nemocí dýchacího ústrojí je použití léku ve formě aerosolu. Jedná se o neinvazivní a rychlý způsob jak dopravit lék do požadované části tracheobronchiálního stromu nebo do krevního oběhu. Ačkoliv se metoda dávkování léků pomocí inhalátorů a nebulizérů používá již delší dobu, stále se řeší otázka účinnosti této metody. Značná část takto dopravovaných léků se nedostane do svého zamýšleného cíle a deponuje v oblastech, kde jejich působení nevyžadujeme. Cílem této práce je pomoci k řešení otázky průchodnosti monodispersního, homogenního aerosolu obsahujícího částice mikronových velikostí skrze horní část dýchacích cest. Tato práce byla vypracována s využitím numerických simulací provedených metodou konečných objemů v programu na bázi výpočtové mechaniky kontinua. Turbulence byla modelována metodou Reynoldsova středování Navier – Stokesových rovnic s využitím dvourovnicového modelu k-omega SST. Výsledkem práce je analýza proudění během dvou zvolených dýchacích režimů s ohledem na stacionární i cyklický průběh proudění a jejich porovnání s experimenty na totožných geometriích. Dále byla provedena rešerše zjednodušených modelů plic a jejich geometrie použita při výpočtu distribuce vzduchu v modelu dýchacích cest. V závěru práce je pak proveden výpočet depozice aerosolu a proveden rozbor jeho výsledků., One of approaches in treatment of respiratory system diseases is the use of drug particles suspended in air in the form of aerosol. It is a fast and non-invasive method for the delivery of medicine into tracheobronchial tree or bloodstream. Although the method of the medication dosage by means of inhalers or nebulizers is well known, the effectiveness of that approach is still an actual issue. A significant amount of drugs delivered with the use of the medication dosage never reaches its primary destination and the drugs deposit in antecendent areas of respiratory tract where their presence is not required. This thesis deals with a problem of the passage of monodisperse homogenous aerosol with micron-size particles through the upper parts of the respiratory tract. This work was created with the use of numerical simulations carried out by means of the finite volume method in the commercial code based on computational fluid dynamics. Turbulence was modelled using the Reynolds averaged Navier–Stokes equations with the two-equation eddy viscosity k-omega SST model. The main output of the thesis is the analysis of airflow in two respiratory regimes. Stationary and cyclic cases of the flow behaviour were considered and the validation of simulated results with experiments performed on similar geometries was carried out. Furthermore, the review of simplified lung models and their geometries was made and the acquired results were used for the calculation of air distribution in the respiratory tract. The last part of the thesis deals with the calculation of particle deposition and with the analysis of the results.

Vdechovaný aerosol má značný vliv na zdraví každého člověka. Pochopení mechanismů transportu a depozice aerosolu v lidských plicích je nutnou podmínkou jak pro lepší ochranu před toxickými účinky škodlivých částic, tak zejména pro efektivní použití inhalovaných terapeutických aerosolů. Smyslem této dizertační práce proto bylo získat nové poznatky v této oblasti na základě in vitro prováděných experimentů. Pro měření transportu aerosolu byla zvolena fázová Dopplerovská anemometrie, kterou byla měřena současně rychlost i velikost částic. Výsledky byly zpracovány metodami statistické a frekvenční analýzy. Depozice sférických aerosolových částic byla měřena pozitronovou emisní tomografií, fázově kontrastní mikroskopie kombinovaná s automatickou analýzou obrazů byla využita pro měření depozice vláknových částic. Všechny experimenty byly provedeny na fyzických modelech plic vytvořených na základě reálné geometrie. Výsledkem práce jsou poznatky o charakteristikách proudění, přechodu z laminárního do turbulentního režimu, vlivu režimu dýchání a velikosti částic na transport aerosolu a rozložení depozice aerosolu při různých režimech. Porovnáním depozice na realistickém a semirealistickém modelu s válcovými stěnami byl zjištěn zásadní vliv realistické ústní dutiny. Získané poznatky slouží nejen k rozšíření současných znalostí o chování aerosolu v plicích, ale mohou být použity i pro validaci numerických simulací., Human health is significantly influenced by inhaled aerosols. Insight to the aerosol transport and deposition mechanisms is a prerequisite for both, toxicological protection against harmful particles and efficient application of inhaled therapeutic aerosols. The purpose of this doctoral thesis was to gain new knowledge of this topic on the basis of in vitro measurements. Phase-Doppler Anemometry was chosen for aerosol transport measurement, for it allows simultaneous measurement of particle size and velocity. Results were processed by means of statistical methods and frequency analysis. Deposition of spherical aerosol particles was measured by Positron Emission Tomography, while deposition of fibrous aerosol was measured by Phase-Contrast Microscopy combined with automated image analysis. All experiments were performed on physical models created on the basis of the real lung geometry. New knowledge of flow characteristics, transition from laminar to turbulent flow, effect of breathing pattern or particle size on aerosol transport and deposition in human lungs are outcomes of this work. Significant effect of the oral cavity was ascertained due to comparison of aerosol deposition in realistic and semi-realistic model with cylindrical smooth walls. Acquired data not merely extended our knowledge of aerosol behavior in lungs but it can also be used for validation of numerical simulations.

Správne pochopenie depozície aerosólu a jeho správania v dýchacích cestách človeka je nevyhnutné pre zabezpečenie efektívneho podávania medikamentov a ochranu zdravia. Táto bakalárska práca analyzuje usadzovanie 1 µm častíc, v realistickom a idealizovanom modely pľúc na základe dát získaných pozitrónovou emisnou tomografiou (PET) a počítačovou tomografiou (CT). Dáta z PET a CT skenerov boli nahrané do softvéru Carimas 2.0, ktorý bol použitý na získanie hodnôt objemovej rádioaktivity. Získané hodnoty boli skorigované a následne boli vypočítané depozičné charakteristiky. Výsledky boli okomentované a porovnané s predchádzajúcimi štúdiami. Vhodnosť spôsobu analýzy a výpočtov bola kontrolovaná opakovanou analýzou dát a taktiež zopakovaním celého postupu analýzy nezávislou zaškolenou osobou, čím bola potvrdená stabilita a vhodnosť tejto metódy. Popísaný postup môže slúžiť ako podpora pri spracovávaní PET a CT skenov v programe Carimas. Podrobné informácie o depozícii a niekoľko depozičných charakteristík môžu slúžiť pre porovnania s budúcimi štúdiami, experimentmi alebo môžu byť použité pri validácii dát pre počítačom modelovanú depozíciu. Na základe výsledkov môžeme tvrdiť, že hlavným depozičným mechanizmom pre realistický model pľúc je zotrvačný mechanizmus a zmena prietoku aerosólu idealizovaným modelom má len veľmi malý vplyv na depozíciu., Correct understanding of aerosol deposition and behavior in human respiratory tract is crucial for the efficient delivery of medication and health protection. This bachelor thesis analyses deposition of 1µm particles in realistic and idealized lung geometry, from data previously acquired by positron emission tomography (PET) and computed tomography (CT). PET and CT scans were imported into Carimas 2.0 software which was used to obtain value of volumetric radioactivity. Corrections were applied to the acquired values and consequently, deposition characteristics were calculated and reviewed. Data was also compared to previous studies. Methodology of analyses and calculations was validated by duplicity of scans and their analyses, and repetition of analyses by another trained person which confirmed its good stability and credibility of use. Described procedure can serve as an example of possible way to process PET and CT data in Carimas software. Obtained detailed information about deposition and numerous deposition characteristics can be used for comparison in future studies, experiments, or used as data for validation of computer modeled deposition. Based on deposition results, inertial impaction was confirmed to be the dominant deposition mechanism in realistic model of lungs and very little impact of flow rate on deposition was found for idealized model of lungs.