Forced inspiratory measures have been described to reflect the reduction in dyspnoea upon bronchodilation in severe COPD. Based on this we evaluated the applicability and usefulness of a portable device for the assessment of forced inspiration. In 37 patients with COPD (GOLD II/II/IV n = 16/15/6, mean ± SD FEV(1) 46.2 ± 15.4%pred) lung function was recorded prior to inhalation of 24 μg formoterol and 30 min later. Assessments comprised spirometry including forced inspiration, body plethysmography, maximum inspiratory flow (InCheck, Clement Clarke), and changes in dyspnoea via visual analogue scale (VAS). The sequence was repeated on a second day to assess reproducibility. Bronchodilation by formoterol was detectable in all functional indices (p < 0.05 each) except total lung capacity. FEV(1) improved by (mean ± SD) 11.1 ± 10.3%, forced inspiratory volume in 1s (FIV(1)) by 11.6 ± 13.5%, inspiratory peak flow (PIF) by 10.7 ± 16.2%, and inspiratory flow determined by the InCheck device (IF-IC) by 11.9 ± 14.4%. Remarkably, the changes of IF-IC (p < 0.001) but not those of other measures except FIV(1) (p < 0.05) were related to those of dyspnoea. Effects on IF-IC showed reproducibility comparable to that of other indices. The results suggest that a simple, portable device for recording forced inspiration could be useful in monitoring COPD, as a functional correlate of acute changes in dyspnoea.

Tuberculosis (TB) of the oral cavity is extremely rare and thus presents a diagnostic challenge. We report a case of primary TB in a very uncommon location, the buccal cheek. The initial clinical presentation was a painless swelling of the left cheek and a fistulous tract distal to the lower third molar, reaching the ascending ramus of the left mandible. The histological diagnosis with Ziehl-Neelsen and period acid-Schiff staining failed to demonstrate micro-organisms. To rule out TB, a biopsy specimen was tested by polymerase chain reaction (PCR) for the presence of mycobacterial DNA. Direct sequencing of the PCR product revealed DNA specific for mycobacteria of the TB complex. The oral lesions resolved completely after anti-TB chemotherapy. Although routine microbiologic sampling is not recommended for dental surgical procedures, this case encourages the clinician to include molecular and microbiological techniques as an important diagnostic tool for ambiguous cases that demonstrate no response to common therapy, to rule out mycobacterial infection.

The viscosity of the nematic liquid crystal PCH-5 [4-(trans-4′-pentylcyclohexyl)-benzonitrile], measured in the presence of an electric field parallel to the gradient of the velocity, shows a complex dependence both on magnitude E of the electric field and on the shear rate γ̇. When plotted versus E2/γ̇, all data points fall unto a master curve. In nonequilibrium molecular dynamics computer simulations, performed for a Gay–Berne model fluid, the corresponding influence of a magnetic field on the viscosity was calculated. In both cases, the shape of the master curve for the viscosity can be computed by considering the competition between the torques exerted by the velocity gradient and by the orienting field. It involves the Leslie viscosity coefficients γ1 and γ2, the Miesowicz and Helfrich viscosities η1,η2, and η12. Thus it should be possible to extract these coefficients from the data. This is straightforward in the magnetic case since the molecules in the fluid “see” the externally applied field. The internal electric field, however, differs from the applied field E. When this effect is taken into account, using the known experimental values for dielectric coefficients ε‖ and ε⊥, the electro-rheological master curve agrees very well with the experimental data. Values for the viscosity coefficients are obtained and presented.

Viscosities η were measured for moderately concentrated (15.5wt%) solutions of poly(ether imide) (PEI) as a function of the composition of the cosolvent tetrahydrofuran (THF) plus γ-butyrolactone (γ-BL). The solutions are almost by a factor of four less viscous when THF predominates than when γ-BL is the major component of the solvent mixture. Furthermore, the viscosity passes a minimum as the composition of the mixed solvent is varied. Both observations can be well understood in terms of the viscosities of the mixed solvents and the hydrodynamic interaction between the polymer molecules. The pronounced dissymmetry of η as a function of the composition of the mixed solvent η results from the fact that the viscosity of γ-BL is three times larger than that of THF. The minimum in η reflects the dependence of the thermodynamic quality of the mixed solvent on its composition. With increasing predominance of one component the solvent deteriorates and additional polymer/polymer contacts—leading to an augmentation of η-are formed.

The thermodynamic interactions in the ternary mixture tetrahydrofuran/γ-butyrolactone/poly(ether imide) (THF/γ-BL/PEI) are investigated from 30 to 50°C. This is a membrane-forming system with a high He-selectivity. Cloud point measurements show that the two binary polymer solutions THF/PEI and γ-BL/PEI exhibit miscibility gaps which close towards the centre of the ternary phase diagram where the mixtures become homogeneous (cosolvency). Vapour pressures were determined for the subsystem THF/γ-BL. For the theoretical calculations the Gibbs energy of mixing is formulated according to the Flory-Huggins theory and the interaction parameter χTHFγ-BL calculated from the vapour pressures. The adjustment of theoretical phase diagrams to the experimental data (cloud point curves, tie lines and critical points) gives access to χTHFPEI and χγ-BLPEI. For a satisfactory representation of the liquid-liquid demixing, a concentration dependent χTHFPEI is required, whereas concentration independent values for χTHFγ-BL and χγ-BLPEI suffice.