Acquired cystic fibrosis transmembrane conductance regulator dysfunction in the lower airways in COPD

BACKGROUND

Cigarette smoke and smoking-induced inflammation decrease cystic fibrosis transmembrane conductance regulator (CFTR) activity and mucociliary transport in the nasal airway and cultured bronchial epithelial cells. This raises the possibility that lower airway CFTR dysfunction may contribute to the pathophysiology of COPD. We compared lower airway CFTR activity in current and former smokers with COPD, current smokers without COPD, and lifelong nonsmokers to examine the relationships between clinical characteristics and CFTR expression and function.

METHODS

Demographic, spirometry, and symptom questionnaire data were collected. CFTR activity was determined by nasal potential difference (NPD) and lower airway potential difference (LAPD) assays. The primary measure of CFTR function was the total change in chloride transport (Δchloride-free isoproterenol). CFTR protein expression in endobronchial biopsy specimens was measured by Western blot.

RESULTS

Compared with healthy nonsmokers (n = 11), current smokers (n = 17) showed a significant reduction in LAPD CFTR activity (Δchloride-free isoproterenol, -8.70 mV vs -15.9 mV; P = .003). Similar reductions were observed in smokers with and without COPD. Former smokers with COPD (n = 7) showed a nonsignificant reduction in chloride conductance (-12.7 mV). A similar pattern was observed for CFTR protein expression. Univariate analysis demonstrated correlations between LAPD CFTR activity and current smoking, the presence of chronic bronchitis, and dyspnea scores.

CONCLUSIONS

Smokers with and without COPD have reduced lower airway CFTR activity compared with healthy nonsmokers, and this finding correlates with disease phenotype. Acquired CFTR dysfunction may contribute to COPD pathogenesis.

Degradation of paracetamol by catalytic wet air oxidation and sequential adsorption - Catalytic wet air oxidation on activated carbons

The concern about the fate of pharmaceutical products has raised owing to the increasing contamination of rivers, lakes and groundwater. The aim of this paper is to evaluate two different processes for paracetamol removal. The catalytic wet air oxidation (CWAO) of paracetamol on activated carbon was investigated both as a water treatment technique using an autoclave reactor and as a regenerative treatment of the carbon after adsorption in a sequential fixed bed process. Three activated carbons (ACs) from different source materials were used as catalysts: two microporous basic ACs (S23 and C1) and a meso- and micro-porous acidic one (L27). During the first CWAO experiment the adsorption capacity and catalytic performance of fresh S23 and C1 were higher than those of fresh L27 despite its higher surface area. This situation changed after AC reuse, as finally L27 gave the best results after five CWAO cycles. Respirometry tests with activated sludge revealed that in the studied conditions the use of CWAO enhanced the aerobic biodegradability of the effluent. In the ADOX process L27 also showed better oxidation performances and regeneration efficiency. This different ageing was examined through AC physico-chemical properties.

Competitive adsorption of phenolic compounds from aqueous solution using sludge-based activated carbon

Preparation of activated carbon from sewage sludge is a promising approach to produce cheap and efficient adsorbent for pollutants removal as well as to dispose of sewage sludge. The first objective of this study was to investigate the physical and chemical properties (BET surface area, ash and elemental content, surface functional groups by Boehm titration and weight loss by thermogravimetric analysis) of the sludge-based activated carbon (SBAC) so as to give a basic understanding of its structure and to compare to those of two commercial activated carbons, PICA S23 and F22. The second and main objective was to evaluate the performance of SBAC for single and competitive adsorption of four substituted phenols (p-nitrophenol, p-chlorophenol, p-hydroxy benzoic acid and phenol) from their aqueous solutions. The results indicated that, despite moderate micropore and mesopore surface areas, SBAC had remarkable adsorption capacity for phenols, though less than PICA carbons. Uptake of the phenolic compound was found to be dependent on both the porosity and surface chemistry of the carbons. Furthermore, the electronegativity and the hydrophobicity of the adsorbate have significant influence on the adsorption capacity. The Langmuir and Freundlich models were used for the mathematical description of the adsorption equilibrium for single-solute isotherms. Moreover, the Langmuir-Freundlich model gave satisfactory results for describing multicomponent system isotherms. The capacity of the studied activated carbons to adsorb phenols from a multi-solute system was in the following order: p-nitrophenol > p-chlorophenol > PHBA > phenol.

Ultrasound in gas-liquid systems: effects on solubility and mass transfer

The effect of ultrasound on the pseudo-solubility of nitrogen in water and on gas-liquid mass transfer kinetics has been investigated in an autoclave reactor equipped with a gas induced impeller. In order to use organic liquids and to investigate the effect of pressure, gas-liquid mass transfer coefficient was calculated from the evolution of autoclave pressure during gas absorption to avoid any side-effects of ultrasound on the concentrations measurements. Ultrasound effect on the apparent solubility is very low (below 12%). Conversely ultrasound greatly improves gas-liquid mass transfer, especially below gas induction speed, this improvement being boosted by pressure. In typical conditions of organic synthesis: 323 K, 1100 rpm, 10 bar, k(L).a is multiplied by 11 with ultrasound (20 kHz/62.6 W). The impact of sonication is much higher on gassing out than on gassing in. In the same conditions, this enhancement is at least five times higher for degassing.

Crystallization of potash alum: effect of power ultrasound

The influence of power ultrasound on the crystallization of potash alum was investigated. Experiments have been carried out in a batch stirred vessel. It was found that ultrasonic waves decrease the supersaturation limits and modify the morphology of the crystals produced. The average crystal size decreases with an increase of ultrasonic power. To investigate also the action of ultrasound on already existing crystals, crystals produced in silent conditions were suspended in saturated potash alum solution at various ultrasonic powers. The results show that ultrasound has also an abrasive effect on potash alum crystals for high power inputs.

Emulsification processes: on-line study by multiple light scattering measurements

The use of ultrasound in various processes of the chemical industry has been a subject of research and development for many years. As regards in emulsification, apart from formulation variables, power is the most important parameter. Efficiency of emulsification processes may be followed and evaluated by measuring particle size distribution, which mainly governs the kinetic stability of such dispersions. Unfortunately, this kind of measurement must be performed at high dilution (low volume fraction of dispersed phase). The present work is devoted to the on-line study of ultrasound emulsification by means of a newly developed apparatus based on multiple light scattering, which allows us to determine average droplet diameter and its variations directly on concentrated media. The model system was an oil (kerosene)-in-water emulsion stabilized by a polyethoxylated sorbitan monostearate.

Ultrasound in organic electrosynthesis

Mechanical effects induced by ultrasonication can be very helpful for the activation of electrochemical reactions. The continuous cleaning of the electrodes by ultrasound irradiation of the electrochemical cell or the enhancement of mass transfer at the electrodes are examples of such activation. Finally, ultrasonication can play an important part for the orientation of reactions whose selectivities are very sensitive to stirring. Two very different examples have been chosen to illustrate these phenomena: the indirect electrooxidation of di-ketone-L-sorbose into the corresponding ketogulonic acid and the direct electroreduction of acetophenone into pinacol.

Characterisation of the acoustic cavitation cloud by two laser techniques

An experimental investigation of the size and volumetric concentration of acoustic cavitation bubbles is presented. The cavitation bubble cloud is generated at 20 kHz by an immersed horn in a rectangular glass vessel containing bi-distilled water. Two laser techniques, laser diffraction and phase Doppler interferometry, are implemented and compared. These two techniques are based on different measuring principles. The laser diffraction technique analyses the light pattern scattered by the bubbles along a line-of-sight of the experimental vessel (spatial average). The phase Doppler technique is based on the analysis of the light scattered from single bubbles passing through a set of interference fringes formed by the intersection of two laser beams: bubble size and velocity distributions are extracted from a great number of single-bubble events (local and temporal average) but only size distributions are discussed here. Difficulties arising in the application of the laser diffraction technique are discussed: in particular, the fact that the acoustic wave disturbs the light scattering patterns even when there are no cavitation bubbles along the measurement volume. As a consequence, a procedure has been developed to correct the raw data in order to get a significant bubble size distribution. After this data treatment has been applied the results from the two measurement techniques show good agreement. Under the emitter surface, the Sauter mean diameter D(3, 2) is approximately 10 microm by phase Doppler measurement and 7.5 microm by laser diffraction measurement at 179 W. Note that the mean measured diameter is much smaller than the resonance diameter predicted by the linear theory (about 280 microm). The influence of the acoustic power is investigated. Axial and radial profiles of mean bubble diameters and void fraction are also presented.

Influence of ultrasound on mixing on the molecular scale for water and viscous liquids

Micromixing has a decisive action on the yield of fast reactions such as combustions, polymerizations, neutralizations and precipitations. The aim of this study was to test the possible effect of ultrasound on micromixing, through the phenomenon of acoustic cavitation. To evaluate the local state of micromixing, we used a system of parallel competing reactions involving the Dushman reaction between iodide and iodate, coupled with a neutralization. At first, we studied the effects of the acoustic frequency on micromixing (20-540-1000 kHz). It was found that micromixing through acoustic cavitation and acoustic streaming was more important at 20 kHz than at 540 kHz or 1 MHz. At high and low frequency, it was shown that the injection must be located near the ultrasonic emitter. The influence of the acoustic intensity proved to be predominant mostly for low intensities; for an acoustic intensity of 10 W cm(-2), a characteristic micromixing time of about 0.015 s has been obtained. Viscous media have been studied and experiments showed that micromixing is more difficult to achieve than in aqueous media, but that ultrasound may be as effective as classic stirring.

Emulsification by ultrasound: drop size distribution and stability

The aim of this work is to compare the oil-in-water emulsions produced by mechanical agitation (Ultra-Turrax, 10,000 rpm, P = 170 W) or power ultrasound (ultrasound horn, 20 kHz, 130 W) using the same model system: water/kerosene/polyethoxylated (20 EO) sorbitan monostearate. The following parameters were varied: emulsification time, surfactant concentration, consumed power and volume fraction of oil. With ultrasound, the drop size (Sauter diameter, d32) is much smaller than that given by mechanical agitation under the same conditions, which makes insonated emulsions more stable. For a given drop size (d32), less surfactant is required.

Comparison of ultrasound effects in different reactors at 20 kHz

To compare the performances of three power ultrasonic devices at 20 kHz: a horn, a cup horn and a tube, the local intensity distributions of local effects of cavitation have been investigated. The sensor is an electrochemical probe, measuring the solid-liquid mass transfer rate, related to the cavitation intensity. The axial and radial profiles of mass transfer coefficients have been investigated in three devices, at various power inputs. In all these equipments very strong heterogeneities have been characterized, whether a standing wave appears or not.

A comparative study of local sensors of power ultrasound effects: electrochemical, thermoelectrical and chemical probes

In order to propose standard methods for the local measurement of the effects of power ultrasound inside a reactor, we compare three methods: a chemical dosimeter (Weissler reaction), a thermal sensor (embedded thermocouple) and an electrochemical probe (developed in our laboratory). The same emission device, i.e. the resonant tube (Sonitube-Sodeva), was used for all these methods. Similar trends were observed using various measurements: ultrasound effects vary significantly along the tube axis (due to standing waves in the resonant tubular emitter), but only slightly from the tube axis to the wall. More reliable and reproducible results were obtained with the thermal and electrochemical probes than with the chemical dosimeter.

Modelling of free radicals production in a collapsing gas-vapour bubble

This paper deals with a model linking bubble dynamics under an acoustic pressure field and production of free radicals in the resulting collapses of this bubble. The bubble dynamics model includes interdiffusion of gas and vapour in the bubble as well as evaporation or condensation at the interface, and it assumes uniformity of the internal pressure and perfect gas law for the gas vapour mixture. At the maximum compression of the bubble, all the reactions of dissociation which can occur are assumed at thermodynamic equilibrium. The local composition (especially in free radicals) in the bubble is then calculated by an algorithm based on free energy minimization using the information concerning the maximum compression provided by the bubble dynamics model resolution. Using this model a comparison of free radicals production has been made for two different driving frequencies (20 kHz and 500 kHz), and at given bubble radius and acoustic pressure, an optimum of liquid bulk temperature has been derived for the production of free radicals very similar to the experimental one concerning oxidation reactions in aqueous phase.