345 research outputs found

    High-speed laser image analysis of plume angles for pressurised metered dose inhalers: the effect of nozzle geometry

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    The aim of this study is to investigate aerosol plume geometries of pressurised metered dose inhalers (pMDIs) using a high-speed laser image system with different actuator nozzle materials and designs. Actuators made from aluminium, PET and PTFE were manufactured with four different nozzle designs: cone, flat, curved cone and curved flat. Plume angles and spans generated using the designed actuator nozzles with four solution-based pMDI formulations were imaged using Oxford Lasers EnVision system and analysed using EnVision Patternate software. Reduced plume angles for all actuator materials and nozzle designs were observed with pMDI formulations containing drug with high co-solvent concentration (ethanol) due to the reduced vapour pressure. Significantly higher plume angles were observed with the PTFE flat nozzle across all formulations, which could be a result of the nozzle geometry and material’s hydrophobicity. The plume geometry of pMDI aerosols can be influenced by the vapour pressure of the formulation, nozzle geometries and actuator material physiochemical properties

    The effect of active pharmaceutical ingredients on aerosol electrostatic charges from pressurized metered dose inhalers

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    Purpose. This study investigated the effect of different active pharmaceutical ingredients (API) on aerosol electrostatic charges and aerosol performances for pressurized metered dose inhalers (pMDIs), using both insulating and conducting actuators. Methods. Five solution-based pMDIs containing different API ingredients including: beclomethasone dipropionate (BDP), budesonide (BUD), flunisolide (FS), salbutamol base (SB) and ipratropium bromide (IPBr) were prepared using pressure filling technique. Actuator blocks made from nylon, polytetrafluoroethylene (PTFE) and aluminium were manufactured with 0.3 mm nominal orifice diameter and cone nozzle shape. Aerosol electrostatics for each pMDI formulation and actuator were evaluated using the electrical low-pressure impactor (ELPI) and drug depositions were analysed using high performance liquid chromatography (HPLC). Results. All three actuator materials showed the same net charge trend across the five active drug ingredients, with BDP, BUD and FS showing positive net charges for both nylon and PTFE actuators, respectively. While SB and IPBr had significantly negative net charges across the three different actuators, which correlates to the ionic functional groups present on the drug molecule structures. Conclusions. The API present in a pMDI has a dominant effect on the electrostatic properties of the formulation, overcoming the charge effect arising from the actuator materials. Results have shown that the electrostatic charges for a solution-based pMDI could be related to the interactions of the chemical ingredients and change in the work function for the overall formulation

    The effect of actuator nozzle designs on the electrostatic charge generated in pressurised metered dose inhaler aerosols

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    Purpose To investigate the influence of different actuator nozzle designs on aerosol electrostatic charges and aerosol performances for pressurised metered dose inhalers (pMDIs). Methods Four actuator nozzle designs (flat, curved flat, cone and curved cone) were manufactured using insulating thermoplastics (PET and PTFE) and conducting metal (aluminium) materials. Aerosol electrostatic profiles of solution pMDI formulations containing propellant HFA 134a with different ethanol concentration and/or model drug beclomethasone dipropionate (BDP) were studied using a modified electrical low-pressure impactor (ELPI) for all actuator designs and materials. The mass of the deposited drug was analysed using high performance liquid chromatography (HPLC). Results Both curved nozzle designs for insulating PET and PTFE actuators significantly influenced aerosol electrostatics and aerosol performance compared with conducting aluminium actuator, where reversed charge polarity and higher throat deposition were observed with pMDI formulation containing BDP. Results are likely due to the changes in plume geometry caused by the curved edge nozzle designs and the bipolar charging nature of insulating materials. Conclusions This study demonstrated that actuator nozzle designs could significantly influence the electrostatic charges profiles and aerosol drug deposition pattern of pMDI aerosols, especially when using insulating thermoplastic materials where bipolar charging is more dominant

    Steroid-associated hip joint collapse in bipedal emus

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    In this study we established a bipedal animal model of steroid-associated hip joint collapse in emus for testing potential treatment protocols to be developed for prevention of steroid-associated joint collapse in preclinical settings. Five adult male emus were treated with a steroid-associated osteonecrosis (SAON) induction protocol using combination of pulsed lipopolysaccharide (LPS) and methylprednisolone (MPS). Additional three emus were used as normal control. Post-induction, emu gait was observed, magnetic resonance imaging (MRI) was performed, and blood was collected for routine examination, including testing blood coagulation and lipid metabolism. Emus were sacrificed at week 24 post-induction, bilateral femora were collected for micro-computed tomography (micro-CT) and histological analysis. Asymmetric limping gait and abnormal MRI signals were found in steroid-treated emus. SAON was found in all emus with a joint collapse incidence of 70%. The percentage of neutrophils (Neut %) and parameters on lipid metabolism significantly increased after induction. Micro-CT revealed structure deterioration of subchondral trabecular bone. Histomorphometry showed larger fat cell fraction and size, thinning of subchondral plate and cartilage layer, smaller osteoblast perimeter percentage and less blood vessels distributed at collapsed region in SAON group as compared with the normal controls. Scanning electron microscope (SEM) showed poor mineral matrix and more osteo-lacunae outline in the collapsed region in SAON group. The combination of pulsed LPS and MPS developed in the current study was safe and effective to induce SAON and deterioration of subchondral bone in bipedal emus with subsequent femoral head collapse, a typical clinical feature observed in patients under pulsed steroid treatment. In conclusion, bipedal emus could be used as an effective preclinical experimental model to evaluate potential treatment protocols to be developed for prevention of ON-induced hip joint collapse in patients

    Study the Compositional Alteration of Gut Microbiome with Different Environmental Factors

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    The microbiome includes all microorganisms within a resident habitant. Advantages of high-throughput sequencing technologies are that we can detect the gut microbiome composition and its relationship with human health and disease. Our overall goal is to study how the gut microbiome compositions are altered by environmental factors and how the altered microbiome affects the host and to apply this knowledge to improve clinical outcomes. Obesity is a risk factor for kidney transplantation as well as many comorbidities. Bariatric surgery has proven to be an effective method of weight management. The combination of BS with kidney transplantation may be a promising way of improving renal function and reducing obesity. In our follow-up study of obese subjects with BS, we observed increased species diversity post-surgery within 6 months with the appearance of Streptococcus species. Eubacterium rectale and Megamonas hypermegale were positively associated with BMI, whereas Streptococcus salivarius was negatively correlated with BMI. Microbial species are also associated with serum cytokine levels. Bacteroides thetataomicron is positively correlated with the anti-inflammatory cytokine IL-13. In the study of infants with cystic fibrosis (CF), we detected associations between growth and gut microbiome in CF infants. The gut microbiome is affected by age, antibiotic prophylaxis, malnutrition, and diet at the genus level. Compared to US-CF infants, AUS-CF infants had lower gut microbiome diversity with a higher abundance of Proteobacteria and a lower abundance of Firmicutes, which may be due to treatment with prophylactic antibiotics. Specifically, enrichment of Klebsiella in Proteobacteria in the AUS-CF was associated with antibiotic prophylaxis treatment. Using allogeneic transplants murine model, we identified the effective Abx components vancomycin and metronidazole to highly prolong graft survival when both were present. Abx treatment reduced bacterial diversity with increased Bacteroides species, including Parabacteroides distasonis and Alistipes finegoldii. Enrichment of commensal bacteria may help alleviate inflammation and thus prolong graft survival. To conclude, we identified the gut microbiome changes upon multiple environmental factors of diseases and medications including antibiotics and how they may improve clinical outcome. Understanding their changes and metabolic functions will highlight future medical applications with disease monitoring, prevention, and intervention

    Exhibitionary Spaces in Japanese Art, 1860s-1970s: Models, Terminologies and Territories

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    This thesis examines the role of exhibitionary spaces during a period that spans the Tokyo artistic milieu‚Äôs localisation of Western European and Northern American concepts of fine art, museum and exhibition, and the establishment of a modern art system. Whereas existing scholarship on these has primarily concentrated on art historical and museological analysis of artists and collections, this thesis demonstrates the need to study exhibitionary spaces, their histories, and the shifting terminology used to describe and define them. Grounded by extensive archival research, this thesis addresses the use of temples, bijutsukan (art-prioritising institutions) and alternative spaces by artists and other key agents who occupied central, peripheral and intermediate positions within the artistic milieu. Drawing from Reiko Tomii‚Äôs collectivism and the Deleuzoguattarian concept of ‚Äėterritory‚Äô, this thesis analyses the exhibitionary operations that these agents deployed, in relation to specific spaces, one another, and the shifting geopolitical dynamics of the specified historical period. It contends that exhibitionary spaces functioned as a physical ground for the artistic milieu‚Äôs localisation of new concepts in the pre-modern period (1868-1907), the establishment of a mainstream institutional system and independent models in the modern period (1907-1945), and the deterritorialisation of artistic and exhibitionary borders during the contemporary period (1945-1970s).</p

    Uncertainty-Aware Transactive Operation Decisions for Grid-Friendly Building Clusters

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    In this thesis, the emerging local energy transaction of prosumer (building) at distribution level is focused. Decision models and efficient algorithms are developed to study the collaborative energy transaction decisions of building clusters in three research phases. Number of research has demonstrated that building clusters can achieve more benefits like lower total energy cost, however, some buildings have to make sacrifices of their own interests for collective interests for the clusters. To motivate individual buildings, we propose four different transactive energy management models in first phase where each building is allowed to have energy transaction with others while individual requirement has to be satisfied. The first model focuses on maximizing collective interests and this model is appropriate when all the buildings are operated by one manager, both collective and individual interests are considered in second model which is suitable when different buildings have heterogeneous individual interests. The third and fourth models aim to maximize both collective and individual interests, this two models are preferred when buildings have homogeneous individual interests (e.g. same saving percentage or absolute saving amount). Then next, in second phase, large scale (e.g. community level) building clusters is studied. To enable more efficient transactive operations among prosumers, we propose a swarm intelligence based bi-level distributed decision approach. Particle swarm optimizer is employed at system level to coordinate all the buildings to dispatch shared energy while each building at sub-system level will employ a mixed integer operating model to obtain operation decisions for its energy systems, such as distributed generators and storage systems. For the purpose of accelerating convergence of swarm algorithm, a marginal price based feedback strategy is proposed. During each iteration, each building will solve its local decision model, the marginal prices for exchanged energy will be collected and fed back to system level to guide velocity and position updating of particle swarm. Proposed distributed approach is applied on distributed control for building-charging station integration as a case study, and then it is evaluated in terms of accuracy, scalability and robustness. It is demonstrated that proposed approach is very computationally efficient, scalable and robust, and the computational complexity if O(n) where n is the number of buildings in the cluster. To deal with uncertain information about electricity load and solar radiation, scenario-based centralized two-stage stochastic operation model is firstly established at third research phase, where electric storage and power generating unit are assumed to provide different kinds of operating reserves in ancillary market. Proposed swarm intelligence based distributed decision framework and coordination algorithm from previous phase are extended to incorporate with stochastic programming. In order to further decrease model complexity of planning optimization and utilize updated information, model prediction control approach is embedded in proposed energy transaction process to make online decisions. In summary, this thesis has proposed a swarm intelligence based methodology of coordinating buildings' transactive operation at distribution level. The main idea is to utilize marginal information from individual optimization to allocate resources more effectively for collective optimality. This methodology could be adopted for more applications, such as robots swarm coordination, etc. There are, however, several issues that could be addressed in future investigations. For example, only electricity transaction is allowed in research phase II and III, multiple transacted energy resources (heating, cooling and electricity) will be considered, and the correlation between different kinds of energy resources will be emphasized. In addition, the energy transaction price of local transaction market is assumed based on transparent information in research phase I. Pricing negotiation mechanism will be worth developed based on game theory to optimally determine local energy transaction price. More broadly, from system perspective, uncertainty coupling and propagation from different sources may have great impacts on the algorithm performance, also communication between system level and subsystem agents may be delayed and missing, therefore distributed coordination algorithm should be robust when facing with such unexpected conditions in practice

    LiDAR Application in Forest Fuel Measurements for Bushfire Hazard Mitigation

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    Australia‚Äôs native Eucalypt forests are the most fire-prone in the world due to high rates of fuel accumulation, high flammability of fuel, and seasonally hot and dry weather conditions. Projected changes in the frequency and intensity of extreme climate and weather could increase the occurrence of ‚Äėmega-fires‚Äô, extreme fire events with catastrophic impacts on people and the environment. Current methods for fire risk mitigation and prediction such as fire danger rating systems, fire behaviour models, and hazard reduction treatments require an accurate description of forest fuel. However, fire management authorities share a common challenge to efficiently and accurately quantify forest fuel properties (e.g. fuel load and fuel structure) at a landscape scale. A landscape includes the physical elements of geo-physically defined landforms, such as forests, grasslands, and lakes. This thesis investigates the application of the Light Detection and Ranging (LiDAR) technique in quantifying forest fuel properties, including fuel structural characteristics and litter-bed fuel load at a landscape scale.<br>¬†<br> ¬†¬†¬†Currently, fire fighters and land managers still rely on empirical knowledge to visually assess forest fuel characteristics of distinct fuel layers. The visual assessment method provides a subjective description of fuel properties that can lead to unreliable fire behaviour prediction and hazard estimation. This study developed a novel method to classify understorey fuel layers in order to quantify fuel structural characteristics more accurately and efficiently by integrating terrestrial LiDAR data and Geographic Information Systems (GIS). The GIS-based analysis and processing procedures allow more objective descriptions of fuel covers and depths for individual fuel layers. The more accurate forest fuel structural information derived from terrestrial LiDAR data can be used to prescribe fire hazard-reduction burns, predict fire behaviour potentials, monitor fuel growth, and conserve forest habitats and ecosystems in multilayered Eucalypt forests.<br>¬†<br> ¬†¬†¬†Traditionally, litter-bed fuel load is directly measured through destructive sampling, sorting, and immediate weighing after oven drying for 24 hours at 105 ¬įC. This direct measurement of fuel load on a landscape scale requires extensive field sampling, post laboratory work and statistical analysis, which is labour intensive and time consuming. This study found new relationships among forest litter-bed fuel load, surface fuel depth, fire history and environmental factors through multiple regressions with airborne and terrestrial LiDAR data. The fuel load models established in this study indicate that litter-bed depth and fire history are the primary predictors in estimating litter-bed fuel load, while canopy density and terrain features are secondary predictors.<br>¬†<br> ¬†¬†¬†Current fuel models are constrained to estimate spatial variations in fuel load within homogeneous vegetation that previously experienced the same fire events. This study developed a predictive model through multiple regression to estimate the spatial distribution of litter-bed fuel load in multilayered eucalypt forests with various fire histories and forest fuel types. This model uses forest structural indices and terrain features derived from airborne LiDAR data as predictors, which can be applied when data on forest fuel types and previous fire disturbances are absent. It can be used to map the litter-bed fuel load distribution at a landscape scale to support regional wildland fire management and planning.<br>¬†<br> ¬†¬†¬†This study indicates that LiDAR allows a more efficient and accurate description of fuel structural characteristics and estimation of litter-bed fuel load. The results from this study can assist fire hazard assessment, fuel reduction treatment, and fire behaviour prediction, and therefore may reduce the impact to communities and environment

    Responsive Lanthanide Coordination Polymer for Hydrogen Sulfide

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    Metal organic coordination polymers have received great attention because of their flexible compositions and architecture. Here, we report the design and synthesis of a responsive lanthanide coordination polymer (LCP) for hydrogen sulfide (H<sub>2</sub>S), utilizing self-assembling of biomolecule nucleotide with luminescent terbium ion (Tb<sup>3+</sup>) and sensitizing silver ion (Ag<sup>+</sup>) in aqueous solution. LCP is highly fluorescent due to the inclusion of Ag<sup>+</sup> ions, which sensitized the fluorescence of Tb<sup>3+</sup> ions. H<sub>2</sub>S can strongly quench the fluorescence of LCP through its high affinity for Ag<sup>+</sup> ions. Such configurated LCP material from initial building blocks showed high sensitivity and selectivity for H<sub>2</sub>S and was applied to the determination of H<sub>2</sub>S in human serum. LCP with Tb<sup>3+</sup> ions also has a long fluorescence lifetime, which allows for time-resolved fluorescence assays, possessing particular advantages to probing H<sub>2</sub>S in biological systems with autofluorescence

    Carbon Dioxide Capture by Diethylenetriamine Hydrobromide in Nonaqueous Systems and Phase-Change Formation

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    Diethylenetriamine hydrobromide ([DETAH]¬≠Br) was used for capturing CO<sub>2</sub> in polyethylene glycol 200 (PEG200) solution, in which phase change was observed. PEG200 could not only act as a cosolvent but also be involved in CO<sub>2</sub> absorption, contributing to biphasic separation and increased CO<sub>2</sub> capacity. The potential applications of the mixtures would take advantage of high CO<sub>2</sub> capacity (1.184 mol/mol [DETAH]¬≠Br), and also less energy consumed when considering the mild regeneration condition and low specific heat of PEG200. This system could be recycled at least for five continuous absorption‚Äďdesorption cycles without significant loss of CO<sub>2</sub> capturing and releasing capability. Spectroscopic analysis revealed a O‚ÄďH¬∑¬∑¬∑:N type of H-bonding, and the stabilizing effects of bromide ion would play important roles in stabilizing the system and preventing the biphasic separation by overcoming the electrostatic attractions in the early stage of CO<sub>2</sub> absorption. It is estimated that such a simple and inexpensive solution provides an excellent alternative to current CO<sub>2</sub> capture technologies
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