Search

Introduction: Use of propellants with high global warming potential (such as HFA-134a) for pressurised metered-dose inhalers (pMDIs) is being phased down. Switching to dry-powder inhalers may not be clinically feasible for all patients; an alternative is reformulation using propellants with low global warming potential. The combination of beclometasone dipropionate/formoterol fumarate/glycopyrronium bromide (BDP/FF/GB) is available for asthma or chronic obstructive pulmonary disease via pMDI using HFA-134a as propellant. This is being reformulated using the low global warming potential propellant HFA-152a. This manuscript reports three studies comparing BDP/FF/GB pharmacokinetics delivered via pMDI using HFA-152a vs HFA-134a., Methods: The studies were four-way crossover, single-dose, randomised, double-blind, in healthy volunteers. In Studies 1 and 2, subjects inhaled four puffs of BDP/FF/GB (Study 1: 100/6/12.5 μg [medium-strength BDP]; Study 2: 200/6/12.5 μg [high-strength]), ingesting activated charcoal in two of the periods (once per propellant). In Study 3, subjects inhaled medium- and high-strength BDP/FF/GB using a spacer. All three studies compared HFA-152a vs HFA-134a in terms of lung availability and total systemic exposure of beclometasone-17-monopropionate (B17MP; active metabolite of BDP), BDP, formoterol and GB. Bioequivalence was concluded if the 90 % confidence intervals (CIs) of the ratios between formulations of the geometric mean maximum plasma concentration (C max ) and area under the plasma concentration-time curve between time zero and the last quantifiable timepoint (AUC 0-t ) for the analytes were between 80 and 125 %., Results: In Studies 1 and 2, systemic exposure bioequivalence (i.e., comparisons without charcoal block) was demonstrated, except for GB C max in Study 2 (upper 90 % CI 125.11 %). For lung availability (i.e., comparisons with charcoal block), B17MP and formoterol demonstrated bioequivalence in both studies, as did BDP in Study 2; in Study 1, BDP upper CIs were 126.96 % for C max and 127.34 % for AUC 0-t ). In Study 1, GB AUC 0-t lower CI was 74.54 %; in Study 2 upper limits were 135.64 % for C max and 129.12 % for AUC 0-t . In Study 3, the bioequivalence criteria were met for BDP, B17MP and formoterol with both BDP/FF/GB strengths, and were met for GB AUC 0-t , although not for C max . Both formulations were similarly well tolerated in all three studies., Conclusions: Overall, while formal bioequivalence cannot be concluded for all analytes, these data suggest therapeutic equivalence of the new formulation with the existing BDP/FF/GB pMDI formulation, therefore supporting reformulation using a propellant with low global warming potential., Competing Interests: Declaration of competing interest FR, MC, AG, KM, AP and GP are employees of Chiesi, the sponsor of the studies. FV and JK are employees of SGS, the clinical trial site. Both have no conflicts of interest to report., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Inhaled corticosteroids (ICS) and β2-agonists are the primary pharmacotherapies of asthma management. However, suboptimal medication compliance is common in asthmatics and is associated with increased morbidity. We hypothesized that exhaled breath measurements of the aerosol used in the inhaled medications might prove useful as surrogate marker for asthma medication compliance. To explore this, 10 healthy controls were recruited and randomly assigned to ICS (Flovent HFA) or short acting bronchodilators (Proventil HFA). Both inhalers contain HFA-134a as aerosol propellant. Exhaled breath sampling and pulmonary function tests were performed prior to the inhaler medication dispersion, immediately after inhalation, then at 2, 4, 6, 8, 24, and 48 hours postadministration. At baseline, mean (SD) levels of HFA-134a in the breath were 252 (156) pptv. Immediately after inhalation, HFA-134a breath levels increased to 300 × 10(6) pptv and were still well above ambient levels 24 hours postadministration. The calculated ratio of forced expiratory volume in 1 second over forced vital capacity did not change over time following inhaler administration. This study demonstrates, for the first time, that breath HFA-134a levels can be used to assess inhaler medication compliance. It may also be used to evaluate how effectively the medicine is delivered.

Cryogen spray cooling (CSC) is a technique employed to reduce the risk of epidermal damage during dermatologic laser surgery. However, while CSC protects the epidermis from non-specific thermal damage, it might reduce the effective fluence reaching the target chromophore due to scattering of light by the spray droplets and subsequent water condensation/freezing on the skin surface. The objective of this work was to study the effect of ambient humidity (omega) on light transmittance during CSC. An integrating sphere was employed to measure the dynamics of light transmittance through a deformable agar phantom during CSC. The study included two representative CSC spurt patterns studied using four omega: 57, 40, 20 and 12%. Results show that during CSC, as omega increased, light transmittance decreased. For the highest humidity level (57%) studied, light transmittance reached a minimum of 55% approximately 30 ms after spurt termination. In a controlled environment with omega = 12%, light transmittance reached a minimum of 87% approximately 30 ms after spurt termination. The reduced light transmittance immediately after spurt termination was most likely because of scattering of light caused by condensation of water vapour due to aggressive cooling of ambient air in the wake of the cryogen spurt.

Cryogen spray cooling (CSC) is used to minimize the risk of epidermal damage during laser dermatologic therapy. However, the dominant mechanisms of heat transfer during the transient cooling process are incompletely understood. The objective of this study is to elucidate the physics of CSC by measuring the effect of initial substrate temperature (T0) on cooling dynamics. Cryogen was delivered by a straight-tube nozzle onto a skin phantom. A fast-response thermocouple was used to record the phantom temperature changes before, during and after the cryogen spray. Surface heat fluxes (q") and heat-transfer coefficients (h) were computed using an inverse heat conduction algorithm. The maximum surface heat flux (q"max) was observed to increase with T0. The surface temperature corresponding to q"max also increased with T0 but the latter has no significant effect on h. It is concluded that heat transfer between the cryogen spray and skin phantom remains in the nucleate boiling region even if T0 is 80 degrees C.

Although cryogen spray cooling (CSC) is used to minimize the risk of epidermal damage during laser dermatologic surgery, optimization of the current cooling approach is needed to permit the safe use of higher light doses, which should improve the therapeutic outcome in many patients. The objective of this study was to measure the effect of spurt duration (delta t) on the heat transfer dynamics during CSC using a model skin phantom. A fast-response temperature sensor was constructed to record the changes in surface temperature during CSC. Temperature measurements as a function of delta t at two nozzle-to-skin distances (z = 50 and 20 mm) were performed. The average surface heat fluxes (q) and heat transfer coefficients (h) for each delta t were computed using an inverse heat conduction problem algorithm. It was observed that q undergoes a marked dynamic variation during the entire delta t, with a maximum heat flux (qc) occurring early in the spurt (5-15 ms), followed by a quick decrease. The estimated qc vary from 450 to 600 kW m(-2), corresponding to h maxima of 10 and 17-22 kW m(-2) K(-1) for z = 50 and 20 mm, respectively. For z = 50 mm, spurts longer than 40 ms do not increase the total heat removal (Q) within the first 200 ms. However, for z = 20 mm, delta t longer than 100 ms are required to achieve the same Q. It is shown that the heat transfer dynamics and the time it takes to reach qc during CSC can be understood through classic boiling theory as a transition from transient to nucleate boiling. Based on the results of this model skin phantom, it is shown that spurts longer than 40 ms have a negligible impact on both q and Q within clinically relevant cooling times (10-100 ms).

Cryogenic sprays are used for cooling human skin during laser dermatologic surgery. In this paper, six straight-tube nozzles are characterized by photographs of cryogenic spray shapes, as well as measurements of average droplet diameter, velocity, and temperature. A single-droplet evaporation model to predict average spray droplet diameter and temperature is tested using the experimental data presented here. The results show two distinct spray patterns--sprays for 1.4-mm-diameter nozzles (wide nozzles) show significantly larger average droplet diameters and higher temperatures as a function of distance from the nozzle compared with those for 0.5-0.8-mm-diameter nozzles (narrow nozzles). These results complement and support previously reported studies, indicating that wide nozzles induce more efficient heat extraction than the narrow nozzles.

Cryogen spray cooling (CSC) is used to protect the epidermis during dermatologic laser surgery. To date, the relative influence of the fundamental spray parameters on surface cooling remains incompletely understood. This study explores the effects of mass flow rate and average droplet velocity on the surface heat flux during CSC. It is shown that the effect of mass flow rate on the surface heat flux is much more important compared to that of droplet velocity. However, for fully atomized sprays with small flow rates, droplet velocity can make a substantial difference in the surface heat flux.

Fast heat extraction is critically important to obtain the maximal benefit of cryogen spray cooling (CSC) during laser therapy of shallow skin lesions, such as port wine stain birthmarks. However, a film of liquid cryogen can build up on the skin surface, impairing heat transfer due to the relatively low thermal conductivity and higher temperature of the film as compared to the impinging spray droplets. In an attempt to optimize the cryogen mass flux, while minimally affecting other spray characteristics, we apply a series of 10 ms spurts with variable duty cycles. Heat extraction dynamics during such intermittent cryogen sprays were measured using a custom-made metal-disc detector. The highest cooling rates were observed at moderate duty cycle levels. This confirms the presence, and offers a practical way to eliminate the adverse effect of liquid cryogen build-up on the sprayed surface. On the other hand, lower duty cycles allow a substantial reduction in the average rate of heat extraction, enabling less aggressive and more efficient CSC for treatment of deeper targets, such as hair follicles.

Surface cooling, in conjunction with various thermally mediated therapeutic procedures, can provide a means to protect superficial tissues from injury while achieving destruction of deeper targeted structures. We have investigated the thermal response of in-vivo human skin to: 1) contact cooling with a sapphire window (6-12 degrees C); and 2) spray cooling with a freon substitute cryogen [tetrafluoroethane; boiling point approximately -26 degrees C at 1 atmospheric pressure (atm)]. Measurements utilizing infrared radiometry show surface temperature reductions from 30 degrees C to 14-19 degrees C are obtained within approximately 1 s in response to sapphire contact cooling. Surface temperature reductions to values between 5 degrees C and -9 degrees C are obtained in response to 20-100-ms cryogen spurts. Computational results, based on fitting the measured radiometric surface temperature to estimate heat transfer parameters, show: 1) temperature reductions remain localized to approximately 200 microns of superficial tissue; and 2) values of heat flux and total energy removed per unit skin surface area at least doubled when using cryogen spray cooling.

Aerosol application of insecticides as part of an integrated pest management program is becoming more widely adopted in food facilities such as flour mills. However, the method of application and the complex structural features within a facility can impact how insecticide particles travel and settle on surfaces and therefore impact the consistency in efficacy obtained. Here we investigated how the location from which an aerosol insecticide is released impacts the spatial pattern of aerosol deposition, using efficacy against Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae), the confused flour beetle, as a model insects. Concrete bioassay arenas containing T. confusum adults and flour were exposed to two commercial aerosol formulations, pyrethrin + pyriproxyfen and pyrethrin + methoprene, and observed for initial adult knockdown and subsequent mortality. Aerosols were applied from one of three static locations or a fourth application comprised of multiple aerosol release points. The aerosol release position had a significant effect on T. confusum adult knockdown and mortality; both ranged from 0 to 100% depending on bioassay arena location. The multiple aerosol release positions tended to have more bioassay arenas with higher knockdown and mortality, and had a more consistent impact across all arena locations, yet there were still areas on the mill floor where little adult beetle efficacy was observed. The effect of each aerosol on T. confusum adults is a culmination of how the aerosol was applied, the distance the aerosol particles traveled, and the complexity of a milling facility. [ABSTRACT FROM AUTHOR]

Aerosol acidity has significant implications for atmospheric processing, and high time-resolution measurements can provide critical insights into those processes. This paper reports diurnal variations of aerosol acidity characterized using an open thermodynamic system in Guangzhou, China. Hourly measurements of PM 2.5 -associated ionic species and related parameters were carried out during June–September 2013 followed by application of the Extended Aerosol Inorganic Model in open mode to estimate aerosol pH. The model-estimated aerosol pH was 2.4 ± 0.3, and the pH diurnal profile exhibited peaks in the early morning (6 a.m.) and troughs in the afternoon (2 p.m.) that appeared to be constrained by liquid water content (LWC) and free H + . A linear regression model was developed to predict aerosol pH, which performed strongly with 4 variables during daytime (NH 4 + , Na + , SO 4 2− and RH; R 2  = 0.95) and 3 during nighttime (NH 4 + , SO 4 2− and RH; R 2  = 0.91). The effect of aerosol acidity on the partitioning of HNO 3 , HCl and NH 3 was studied based on theoretical considerations and measurement data. The fractions in particulate phase for acidic compounds correlated strongly with pH (R 2  = 0.64–0.69) while that for NH 3 , interestingly, was weak (R 2  = 0.17). Analytical expressions were developed to explain these observations and it was concluded that the partitioning of HCl and HNO 3 was more sensitive to pH compared to that of NH 3 . These results are significant in terms of potential atmospheric depletion rates of HCl and HNO 3 in the region and stress the need for future studies in this direction. [ABSTRACT FROM AUTHOR]

Mass concentrations calculated from Aerodyne's aerosol mass spectrometers depend on particle collection efficiency (CE) and relative ionization efficiency (RIE, relative to the primary calibrant ammonium nitrate). We present new laboratory RIE measurements for a wide range of organic aerosol species (RIEOA). An improved laboratory RIE calibration protocol with size and mass selection of calibrant particles and a light scattering-based detection of CE is used. Simpler calibrations of alcohol RIEs using binary mixtures with NH4NO3 are demonstrated. Models that account for only thermal velocity and electron ionization of vaporized molecules do not reproduce RIEOA measurements, confirming that other processes are significant. The relationship between RIEOA and average carbon oxidation state (), a metric used to describe atmospheric OA, is investigated. An average RIEOA of 1.6 ± 0.5 (2σ) is found for −1.0 < < 0.5, a range consistent with most ambient OA except hydrocarbon-like organic aerosol (HOA) and cooking organic aerosol (COA). RIEOA from 2 to 7 are found for below and above this range. The RIEOA typically used for ambient OA (1.4 ± 0.3) is within the laboratory RIEOA measurement uncertainty of oxidized organic species, but is a factor of 2 to 5 lower than that of reduced species. Such biases in OA mass concentrations have not been observed in published field analyses. Chemically reduced ambient OA may have composition, phase states, or compensating CE effects that are not mimicked well in the laboratory. This work highlights the need for further ambient OA studies to better constrain the composition dependence of ambient RIEOA, and the need to always calibrate with the OA under study for laboratory experiments. Copyright © 2018 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

Aerosol assisted chemical vapour deposition (AACVD) has been used to deposit thin films of ZnO from the single-source precursor [Zn(OC(Me)CHC(Me)N( i Pr)) 2 ] ( 1 ) affording highly transparent (>80%) and conductive films (sheet resistance ∼70 KΩ/sq). Extension of this AACVD method whereby related precursors of the type, [R 2 M(OC(Me)CHC(Me)N( i Pr))] (R = Et, M = Al ( 2 ); R = Me, M = Ga ( 3 )), isolated as oils, were added to the precursor solution allowed for the deposition of aluminium- and gallium-doped ZnO (AZO and GZO) films, respectively. Complexes 1 – 3 were characterised by elemental analysis, NMR and mass spectrometry. Films were deposited in under 30 min at 400 °C, from CH 2 Cl 2 /toluene solutions with a N 2 carrier gas. Herein we report the bulk resistivity, ρ , of AZO (0.252 Ω cm) and GZO (0.756 Ω cm) films deposited from this novel approach. All the films transparency exceeded 80% in the visible, X-ray diffraction (XRD) showed all films to crystallise in the wurtzite phase whilst X-ray photoemission spectroscopy (XPS) confirmed the presence of the Al and Ga dopants in the films, and highlighted the low C-contamination (<5%) this route offers. Investigation of a mechanism analogous to the Kirkendall effect confirmed that heating of GZO films at 1000 °C produced the spinel structure GaZn 2 O 4 . [ABSTRACT FROM AUTHOR]

Dimethyl ether (DME) is widely used as green aerosol propellant, precursor to other organic compounds, or as a clean fuel for diesel engines or in combustion cells. The classic method for producing DME is by dehydration of methanol in a catalytic gas-phase reactor, and purification in a direct sequence of two distillation columns. Reactive distillation (RD) is a much better alternative for DME synthesis, based on process intensification principles. This paper presents the optimal design of novel DME processes based on reactive distillation, and makes a fair comparison with the classic reactor-separation-recycle process (for a plant capacity of 100 ktpy DME). The new RD processes were optimized in terms of minimizing the total annual costs, leading to savings of 30% in CapEx and 6% in energy requirements for the RD process. The results indicate that a RD column is recommended for new DME plants, while a combination of gas-phase reactor and RD is suitable for revamping existing plants. [ABSTRACT FROM AUTHOR]

The appeal of sweet electronic cigarette flavors makes it important to identify the chemical compounds that contribute to their sweetness. While volatile chemicals that produce sweet aromas have been identified in e-liquids, there are no published reports of sugars or artificial sweeteners in commercial e-liquids. However, the sweetener sucralose is marketed as an e-liquid additive to commercial flavors. The primary aims of the study were to determine if sucralose is delivered in sufficient concentration in the inhaled aerosol to enhance flavor sweetness, and whether the amount delivered depends on the e-liquid delivery system. Thirty-two adult smokers rated flavor intensity, sweetness, harshness and liking/disliking for 4 commercial flavors with and without sucralose (1%) using 2 e-cigarette delivery systems (cartridge and tank). Participants alternately vaped normally or with the nose pinched closed to block perception of volatile flavor components via olfaction. LC/MS was used to measure the concentration of sucralose in the e-liquid aerosols using a device that mimicked vaping. Sweetness and flavor intensity were perceived much more strongly when olfaction was permitted. The contribution of sucralose to sweetness was significant only for the cartridge system, and the chemical analysis showed that the concentration of sucralose in the aerosol was higher when the cartridge was used. Together these findings indicate that future regulation of sweet flavor additives should focus first on the volatile constituents of e-liquids with the recognition that artificial sweeteners may also contribute to flavor sweetness depending upon e-cigarette design. [ABSTRACT FROM AUTHOR]

Water condensed on ambient aerosol particles plays significant roles in atmospheric environment, atmospheric chemistry and climate. So far, no instruments are available for real-time monitoring of ambient aerosol liquid water contents (ALWC). In this paper, a novel method is proposed to calculate ambient ALWC based on measurements of a three-wavelength humidified nephelometer system. A humidified nephelometer system measures aerosol light scattering coefficients and backscattering coefficients at three wavelengths under dry and different relative humidity (RH) conditions, and therefore provides measurements of light scattering enhancement factor f(RH). The proposed method of calculating ALWC includes two steps. The first step is estimating total volume concentration of ambient aerosol particles in dry state (Va (dry)) with a machine learning method based on measurements of the "dry" nephelometer. The estimated Va (dry) agrees well with the measured Va (dry). The second step is estimating the volume growth factor Vg(RH) of ambient aerosol particles due to water uptake using f(RH) and +ngström exponent. The ALWC is calculated from the estimated Va (dry) and Vg(RH). Uncertainty analysis of the estimated Va (dry) and Vg(RH) is conducted. This research have bridged the gap between f(RH) and Vg(RH). The advantage of this new method is that the ambient ALWC can be obtained using only measurements from a three-wavelength humidified nephelometer system. This method will facilitate the real-time monitoring of the ambient ALWC and help for studying roles of aerosol liquid water in atmospheric chemistry, secondary aerosol formation and climate change. [ABSTRACT FROM AUTHOR]

The investigation of the potential natural and anthropogenic contribution to atmospheric aerosol particles by using lichen-bag technique was performed in the Agri Valley (Basilicata region, southern Italy). This is an area of international concern since it houses one of the largest European on-shore reservoirs and the biggest oil/gas pre-treatment plant (i.e., Centro Olio Val d'Agri (COVA)) within an anthropized context. In particular, the concentrations of 17 trace elements (Al, Ca, Cd, Cr, Cu, Fe, K, Li, Mg, Mn, Na, Ni, P, Pb, S, Ti, and Zn) were measured in lichen bags exposed in 59 selected monitoring points over periods of 6 months (from October 2011 to April 2012) and 12 months (from October 2011 to October 2012). The general origin of the main air masses affecting the sampling site during the study period was assessed by the back trajectories clustering calculated using the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The results allowed the identification and characterization of the crustal material, smoke, sea salt, sulfate, and anthropogenic trace element contributions to the atmospheric aerosol particles in the study area. Finally, the application of the trend surface analysis (TSA) allowed the study of the spatial distribution of the considered contributions highlighting the existence of a continuous broad variation of these contributions in the area of interest. [ABSTRACT FROM AUTHOR]

The aerosol chemical vapor deposition (ACVD) process has been demonstrated as a promising approach to the single step synthesis of nanostructured metal oxide thin films. Multiple process parameters control the nanostructure morphology and the growth of thin films. This work focuses on utilizing a simulation based approach to understand the role of these parameters in governing the morphology of the thin film. A finite element based computational fluid dynamics model, coupled with a discrete-sectional aerosol model, and a boundary layer diffusion and sintering model has been formulated to predict the evolution of particle size distribution and the morphology of the synthesized nanostructured film. The morphology predicted by the model was validated by experimental observations. The model enables scale up and wider application of the ACVD process and can be extended to other gas phase deposition systems. [ABSTRACT FROM AUTHOR]

The destruction of the ozone layer, it is an extremely serious problem for mankind. Therefore, a number of international agreements were adopted to reduce the production and use of particularly aggressive halocarbons and finding replacement by other substances. The article describes the trend of consumption of ozone-depleting substances in Kazakhstan over the past fifteen years. [ABSTRACT FROM AUTHOR]

Introduction: 1,1-Difluoroethane (HFA-152a) is being developed as an alternative propellant in pressurized metered dose inhalers (pMDIs). As a part of the regulatory development pathway, pharmacology, toxicology and clinical studies have been conducted with inhaled HFA-152a. These studies require fit for purpose regulatory compliant (GxP validated) methods for quantification of HFA-152a from blood., Methods: As HFA-152a is a gas at standard temperature and pressure, novel methods were developed to support the analysis across the wide range of species and concentrations required for regulatory filing., Results: The developed methods utilized a headspace auto sampler coupled to a gas chromatograph (GC) with flame ionization detection. Key factors in the successful method included bringing together fit for purpose approaches to the head space vials, volume of matrix (blood), detection range required for species/study objective, handling / transfer of blood into head space vials and the stability/storage required for the analysis of the samples. The species-specific assays were fully validated under regulatory (GLP) conditions for mouse, rat, rabbit, canine and human and non-regulatory (non GLP) validations for guinea pig and cell culture media., Discussion: Overall the novel approach of head space analysis of whole blood allowed for the development and validation of assays used to generate the toxicokinetic data that supported clinical testing of HFA-152a as a new pMDI propellant., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Although visibility is a widely-used indicator to quantify the aerosol loadings, only a few studies have been analyzed the representativeness of visibility in deriving Aerosol Optical Thickness (AOT). In this paper, ground-based visibility, MODerate-resolution Imaging Spectroradiometer (MODIS) and Multi-angle Imaging SpectroRadiometer (MISR) monthly AOT products between July 2002 and December 2014 were analyzed in order to extract the dominant modes of variability using the Singular Value Decomposition (SVD) method. The method has significant merit to reduce data dimension and examine both spatial and temporal variability simultaneously. Results indicated that the satellite retrieved AOTs agreed well with ground-based visibility in terms of inter-annual variability. The correlation coefficients in the first deseasonalized mode are greater than 0.65 between visibility and satellite AOT products. However, large differences were observed in the seasonal variability between ground-based visibility and AOT. In addition, Aerosol vertical distribution from LIdar climatology of Vertical Aerosol Structure for space-based lidar simulation studies (LIVAS) and cloud data from ground-based meteorological station were used to investigate the seasonal variability disagreement. The AOT values derived from LIVAS extinction coefficients between 0 and 500 m above surface have a stronger relationship with visibility, than total column AOT with visibility. It also indicates that seasonal variation of aerosol vertical distribution is the main cause of the disagreement between two parameters, and the uncertainties of satellite products also contribute to the disagreement. Results in this study highlighted that the visibility observation could only be used to depict the inter-annual AOT and more ancillary information could be used for studying seasonal AOT variation. [ABSTRACT FROM AUTHOR]

This study aims to assess the effects of varying an ethanol co-solvent on the deposition of drug particles in severe asthmatic subjects with distinct airway structures and lung functions using computational fluid dynamics. The subjects were selected from two quantitative computed tomography imaging-based severe asthmatic clusters, differentiated by airway constriction in the left lower lobe. Drug aerosols were assumed to be generated from a pressurized metered-dose inhaler (MDI). The aerosolized droplet sizes were varied by increasing the ethanol co-solvent concentration in the MDI solution. The MDI formulation consists of 1,1,2,2-tetrafluoroethane (HFA-134a), ethanol, and beclomethasone dipropionate (BDP) as the active pharmaceutical ingredient. Since HFA-134a and ethanol are volatile, both substances evaporate rapidly under ambient conditions and trigger condensation of water vapor, increasing the size of aerosols that are predominantly composed of water and BDP. The average deposition fraction in intra-thoracic airways for severe asthmatic subjects with (or without) airway constriction increased from 37%±12 to 53.2%±9.4 (or from 20.7%± 4.6 to 34.7%±6.6) when the ethanol concentration was increased from 1 to 10%wt/wt. However, when the ethanol concentration was further increased from 10 to 20%wt/wt, the deposition fraction decreased. This indicates the importance of selecting appropriate co-solvent amounts during drug formulation development for the treatment of patients with narrowed airway disease. For severe asthmatic subjects with airway narrowing, the inhaled aerosol may benefit from a low hygroscopic effect by reducing ethanol concentration to penetrate the peripheral region effectively. These results could potentially inform the selection of co-solvent amounts for inhalation therapies in a cluster-specific manner., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Given the environmental compulsion to reformulate pressurised metered dose inhalers (pMDI) using new propellants with lower global warming potential, this study investigated how non-volatile excipients can be used to engineer aerosol particle microphysics and drug release. The dynamics of change in particle size, wetting and physical state were measured for single particles (glycerol/ethanol/beclomethasone dipropionate; BDP) in the aerosol phase at different relative humidity (RH) using an electrodynamic balance. BDP dissolution rates were compared for aerosols from pMDI containing different ratios of BDP:glycerol or BDP:isopropyl myristate (IPM). In 45 % RH, ethanol loss was followed by evaporation of condensed water to generate spherical particles with solid inclusions or compact irregular-shaped solid particles, according to the presence or absence of glycerol. In RH > 95 %, condensed water did not evaporate and BDP formed solid inclusions in water/glycerol or water droplets. Varying the non-volatile component, 0-50 % w/w, in pMDI resulted in a concentration-dependent 4-8-fold reduction in BDP dissolution rate. These findings demonstrate that non-volatile excipients provide a means of engineering aerosol properties and, modifying the rate of drug release from aerosol medicines. We also demonstrated differences between particles formed in vitro in ambient humidity versus higher humidity, more like that encountered during oral inhalation., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Precious Akhuemokhan reports financial support and equipment, drugs, or supplies were provided by Chiesi Ltd., (Crown Copyright © 2023. Published by Elsevier B.V. All rights reserved.)

We have investigated efficacy of a diatomaceous earth (DE) and an aerosol formulation thereof for contact and residual effects against the common bed bug, Cimex lectularius L. Efficacy of commercially available DE dust samples varied with the product. DX13 and MotherEarth dusts were significantly more effective than other DE dusts based on their lower lethal doses to kill 50 % of the insects, LD values ( LD s = 0.17 and 0.18 g m, respectively), in contact bioassays with adult bugs. DX13-aerosol demonstrated residual effect in both plastic box and the Petri dish methods. In large plastic boxes mortality of the bed bugs due to residual effect of the aerosol was 98 % at 24 h. The residual effect of DX13™-aerosol in Petri dishes persisted for 21 days. Time to kill 50 % of the insects, LT value, increased from 10.2 h for freshly applied DE dust to 46.1 h for dust aged for 21 days in Petri dishes. Mortality of the bed bugs in the Petri dishes was >97 % at 72 h, not only for fresh DX13™-aerosol residue, but also for residues aged up to 14 days. Mortality was 81 % at 72 h for DX13™-aerosol residue aged for 21 days. Mortality of bed bugs confined on a DX13™-incorporated mattress was 100 % at 48 and 72 h for bugs introduced on the mattress 3 and 32 weeks after manufacture, respectively. We also observed horizontal transfer of DX13™-dust between dead bugs collected from the DX13™-incorporated mattress to untreated ones. We discuss potential use of DX13™ for the management of bed bugs. [ABSTRACT FROM AUTHOR]

The Stokes flow field and aerosol particle deposition from flows in model filters, i.e., separate layers of granules with square and hexagonal structures, have been calculated taking into account the effect of gas slip at granule surface. Approximating formulas have been derived for granule drag forces to a flow. The efficiencies of diffusion collection of particles have been calculated in a wide range of Peclet numbers with allowance for a finite particle size and the existence of a Knudsen boundary layer, the layer thickness being comparable with the particle sizes. The applicability of the cell model to the calculation of granular filters has been discussed. [ABSTRACT FROM AUTHOR]

BACKGROUND Mosquitoes can transmit pathogens through blood feeding. Mosquito control programs conduct surveillance and source reduction, treat mosquito oviposition sites and spray adulticides to protect public health. In some areas, homeowners may contract with private mosquito control companies to address mosquito-related issues. RESULTS We evaluated the efficacy of barrier sprays by comparing weekly host-seeking mosquito abundance at treatment and control properties in a residential neighborhood. The chemical concentration of bifenthrin residue on foliage was quantified, and field-collected mosquitoes, primarily Aedes albopictus, were tested for bifenthrin resistance using bottle bioassays. Mosquito abundance at treatment properties was significantly ( P < 0.05) lower than at control properties. Quantities of bifenthrin detected on foliage from treatment properties was not correlated with mosquito abundance. No bifenthrin resistance was detected in captured mosquitoes. CONCLUSION Based on the rate of application, we expected that chemical analysis of bifenthrin residue would show similar concentrations of bifenthrin on foliage in treatment areas. Although mosquitoes were not bifenthrin resistant, further studies are needed to evaluate the extent to which resistance changes over time with repeated applications. Findings from this study provide insight into control methods commonly used by mosquito control companies and could potentially be used to guide future mosquito management strategies. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Background: Vector control through indoor residual spraying (IRS) has been employed on Bioko Island, Equatorial Guinea, under the Bioko Island Malaria Control Project (BIMCP) since 2004. This study analyses the change in mosquito abundance, species composition and outdoor host-seeking proportions from 2009 to 2014, after 11 years of vector control on Bioko Island. Methods: All-night indoor and outdoor human landing catches were performed monthly in the Bioko Island villages of Mongola, Arena Blanca, Biabia and Balboa from 2009 to 2014. Collected mosquitoes were morphologically identified and a subset of Anopheles gambiae sensu lato (s.l.) were later identified molecularly to their sibling species. Mosquito collection rates, species composition and indoor/outdoor host-seeking sites were analysed using generalized linear mixed models to assess changes in mosquito abundance and behaviour. Results: The overall mosquito collection rate declined in each of the four Bioko Island villages. Anopheles coluzzii and Anopheles melas comprised the An. gambiae s.l. mosquito vector population, with a range of species proportions across the four villages. The proportion of outdoor host-seeking An. gambiae s.l. mosquitoes increased significantly in all four villages with an average increase of 58.8 % [57.9, 59.64 %] in 2009 to 70.0 % [67.8, 72.0 %] in 2014. Outdoor host-seeking rates did not increase in the month after an IRS spray round compared to the month before, suggesting that insecticide repellency has little impact on host-seeking behaviour. Conclusion: While vector control on Bioko Island has succeeded in substantial reduction in overall vector biting rates, populations of An. coluzzii and An. melas persist. Host-seeking behaviour has changed in these An. gambiae s.l. populations, with a shift towards outdoor host-seeking. During this study period, the proportion of host-seeking An. gambiae s.l. caught outdoors observed on Bioko Island increased to high levels, exceeding 80 % in some locations. It is possible that there may be a genetic basis underlying this large shift in host-seeking behaviour, in which case outdoor feeding could pose a serious threat to current vector control programmes. Currently, the BIMCP is preparing for this potential challenge by testing source reduction as a complementary control effort that also targets outdoor transmission. [ABSTRACT FROM AUTHOR]

An isotropic nonlinear viscoelastic constitutive model for solid propellant is proposed. The damage due to cyclic loading and dewetting is modeled. Dewetting is a particle-binder interfacial debonding which induces softening under severe deformation. The cyclic loading effects include rapid a decrease of stress during the unloading and large amount of hysteresis known as Mullins’ effect. These effects are modeled by introducing damage functions in the free energy function. The softening due to dewetting is caused by the formation and growth of voids between the matrix and the particles, and a new damage function is proposed to represent the softening behavior. It is represented as a function of the ratio of the volumetric strains before and after dewetting. The volumetric strain at the onset of dewetting is predicted by using viscoelastic dewetting function, which is derived from the viscoelastic dewetting criterion. Cyclic loading effects are accounted for by employing another damage function which is the function of the octahedral shear strain. In addition to the material nonlinearities caused by the damage, geometrical nonlinearity is also considered. The constitutive model is implemented into the commercial finite element code ABAQUS via the user material subroutine UMAT for stress analysis. Laboratory tests of uniaxial and biaxial specimens for the stress response are performed under several different loading conditions. The material parameters and damage functions are calibrated using uniaxial tests only. The effects of strain rate, temperature and loading conditions on the stress are discussed. The computational results are compared with the experiments. [ABSTRACT FROM AUTHOR]

The dissolution of semi-volatile inorganic gases such as ammonia and nitric acid into the aerosol liquid phase has an important influence on the composition, hygroscopic properties and size distribution of atmospheric aerosol particles. The representation of dissolution in global models is challenging due to inherent issues of numerical stability and computational expense. For this reason, simplified approaches are often taken, with many models treating dissolution as an equilibrium process. In this paper we describe the new dissolution solver HyDiS-1.0 that was developped for the global size-resolved simulation of aerosol inorganic composition. The solver applies a hybrid approach, which allows some particle size increments to establish instantaneous gas-particle equilibrium while others are treated time dependently (or dynamically). Numerical accuracy at a competitive computational expense is achieved by using several tailored numerical formalisms and decision criteria, such as for the time- and size-dependent choice between the equilibrium and dynamic approaches. The new hybrid solver is shown to be in good to excellent agreement with a fully dynamic solver and to have numerical stability across a wide range of numerical stiffness conditions encountered within the atmosphere. We present first results of the solver's implementation into a global aerosol microphysics and chemistry transport model. We find that (1) the new solver predicts surface concentrations of nitrate and ammonium in reasonable agreement with observations over Europe, the US and East Asia; (2) models that assume gas-particle equilibrium will not capture the partitioning of nitric acid and ammonia into Aitken mode sized particles, and thus may be missing an important pathway whereby secondary particles may grow to radiation and cloud-interacting size; and (3) the new hybrid solver's computational expense is modest, at around 10 % of total computation time in these simulations. [ABSTRACT FROM AUTHOR]

We fabricated percolative BaTiO 3 /Zn composite films on copper substrates using a variety of weight concentrations by aerosol deposition. The BaTiO 3 /Zn composite films were deposited in crystalline form, and no secondary phase in the composite film was observed. At the BaTiO 3 /Zn composite films, the Zn contents were measured as 0.78-41.62 vol% by X-ray fluorescence. Their dielectric constants indicated from 62.5 to 367.8 in the case of 0.78-11.8 vol% at 1 kHz. The percolation threshold ( f c ) of BaTiO 3 /Zn composite films is 11.8 vol%, and those critical exponent ( q ) are 0.54, respectively. Therefore, the composite film having Zn content below 11.8 vol% can be used as embedded capacitor. [ABSTRACT FROM AUTHOR]

Columnar and ground-level aerosol optical properties co-located in space and time and retrieved from sun/sky photometer and nephelometer measurements, respectively, have been analyzed to investigate the impact of local and transboundary pollution, to analyze their relationships, and hence to contribute to the aerosol load characterization over the Central Mediterranean. The aerosol optical depth (AOD) at 440 nm, the Ångström exponent (Å) calculated from the AOD at 440 and 675 nm, and the asymmetry parameter ( g) at 440 nm represent the investigated columnar aerosol parameters. The scattering coefficient ( σ) at 450 nm, the scattering Ångström exponent (å) calculated from σ at 450 and 635 nm, and the asymmetry parameter ( g) at 450 nm are the corresponding ground-level parameters. It is shown that the columnar and ground-level aerosol properties were significantly and similarly affected by the main airflows identified with backtrajectory cluster analysis. The yearly averaged daily evolution of σ, å, and g was fairly correlated to the one of the AOD, Å, and g, respectively. These results indicate that the aerosol particles were on average characterized by similar yearly averaged optical properties up to the ground level. In particular, the yearly means of columnar and ground-level Ångström exponents, 1.3 ± 0.4 and 1.1 ± 0.4, respectively, which are close to one, reveal a coarse-mode aerosol contribution in addition to the fine-mode particle contribution up to the ground level. Hourly means, day-by-day, and seasonal daily patterns of ground-level parameters were, however, very weakly correlated with the corresponding columnar parameters. The large impact of the local meteorology on the daily evolution of the ground-level aerosol properties, which makes the impact of long-range transported particles less apparent, was mainly responsible for these last results. It has also been found that columnar Ångström exponents much smaller than one may not be linked to å values smaller than 1. This may occurs when coarse-mode particle plumes, advected at high altitudes, do not penetrate inside the planetary boundary layer. Ångström exponents smaller than 1 are due to a significant contribution of coarse-mode particles as dust particles. Therefore, it is shown that å represents one of the best parameters to infer the contribution of coarse-mode particles at the ground level. The daily evolution of the aerosol properties referring to working days (Monday to Friday) and Sunday and the weekly cycle have suggested that the aerosol source contributions varied during the weekends. In particular, the AOD was characterized by a negative weekly cycle (higher AOD values during the weekend than during the weekdays), the Sunday σ daily mean was 11 % larger than the Monday value, and å reached the highest value on Sunday. The impact up to the ground level of the weekdays' transboundary pollution, which reaches the monitoring site during the weekends, has likely contributed to these results. [ABSTRACT FROM AUTHOR]

Optical and micro-physical features of aerosol are reported using Skyradiometer (POM-01L, Prede, Japan) observations taken from a high-altitude station Merak, located in north-eastern Ladakh of the western trans-Himalayas region during January 2011 to December 2013. The observed daily mean aerosol optical depth (AOD, at 500 nm) at the site varied from 0.01 to 0.14. However, 75 % of the observed AOD lies below 0.05 during the study period. Seasonal peaks of AOD occurred in spring as 0.06 and minimum in winter as 0.03 which represents the aged background aerosols at the site. Yearly mean AOD at 500 nm is found to be around 0.04 and inter-annual variations of AOD is very small (nearly ±0.01). Angstrom exponent ( a) varied seasonally from 0.73 in spring to 1.5 in autumn. About 30 % of the observed a lies below 0.8 which are the indicative for the presence of coarse-mode aerosols at the site. The station exhibits absorbing aerosol features which prominently occurred during spring and that may be attributed by the transported anthropogenic aerosol from Indo-Gangatic Plain (IGP). Results were well substantiated with the air mass back-trajectory analysis. Furthermore, seasonal mean of single scattering albedo (SSA at 500 nm) varied from of 0.94 to 0.98 and a general increasing trend is noticed from 400 to 870 nm wavelengths. These features are apparently regional characteristics of the site. Aerosol asymmetry factor (AS) decreases gradually from 400 to 870 nm and varied from 0.66 to 0.69 at 500 nm across the seasons. Dominance of desert-dust aerosols, associated by coarse mode, is indicated by tri-modal features of aerosol volume size distribution over the station during the entire seasons. [ABSTRACT FROM AUTHOR]

To understand the boundary layer characteristics and pathways of aerosol-cloud interaction, an Integrated Ground Observational Campaign, concurrent with Cloud Aerosol Interaction and Precipitation Enhancement Experiment, was conducted by the Indian Institute of Tropical Meteorology, Pune, under Ministry of Earth Sciences at Mahabubnagar (a rural environment, which is ~100 km away from an urban city Hyderabad in Andhra Pradesh), during the period of July-November 2011. Collected samples of PM and PM were analyzed for water-soluble ionic species along with organic carbon (OC) and elemental carbon (EC). During study period, the average mass concentrations of PM and PM were about 50(±10) and 69(±14) μg m, respectively, which are significantly higher than the prescribed Indian National Ambient Air Quality Standards values. The chemical species such as sum of anions and cations from measured chemical constituents were contributed to be 31.27 and 38.49 % in PM and 6.35 and 5.65 % to the PM, whereas carbonaceous species contributed ~17.3 and 20.47 % for OC and ~3.0 and 3.10 % for EC, respectively. The average ratio of PM/PM during study period was ~0.73(±0.2), indicating that the dominance of fine size particles. Carbonaceous analysis results showed that the average concentration of OC was 14 and 8.7 μg m, while EC was 2.1 and 1.5 μg m for PM and PM, respectively. The ratios between OC and EC were estimated, which were 6.6 and 5.7 for PM and PM, suggesting the presence of secondary organic aerosol. Total carbonaceous aerosol accounts 23 % of PM in which the contribution of OC is 20 % and EC is 3 %, while 20 % of PM mass in which the contribution of OC is 17 % and EC is 3 %. Out of the total aerosols mass, water-soluble constituents contributed an average of 45 % in PM and 38 % in PM including about 39 % anions and 6 % cations in PM, while 31 % anions and 7 % cations in PM aerosol mass collectively at study site. [ABSTRACT FROM AUTHOR]

This article presents the synthesis and characterisation (Fourier transform infrared spectroscopy, [sup 1]H NMR and [sup 13]C NMR spectroscopy, CHNS (carbon, hydrogen, nitrogen, sulfur) analysis, atomic absorption spectrometry, and single-crystal X-ray diffraction) of a single source molecular precursor 1-(2-fluorolbenzoyl)-3-(3-ferrocenylphenyl)selenourea (M2F). This precursor has been used for the fabrication of FeSe thin films by aerosol-assisted chemical vapour deposition (AACVD) in the presence of different concentrations of two different surfactants (triton and span) keeping all other conditions the same. Fabricated thin films have been characterised with powder X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The interaction of the surfactants with the precursor (M2F) has been evaluated with cyclic voltammetry and UV-vis spectroscopy. [ABSTRACT FROM AUTHOR]