The structural organization in mixtures of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF(4)])/water or methanol was studied by infrared spectroscopy. No drastic change in the concentration dependence of the alkyl C-H band frequency was observed at high concentration of the ionic liquid. This behavior indicates a clustering of the ionic liquid in alkyl regions. Nevertheless, the presence of methanol significantly perturbs the ionic liquid-ionic liquid associations in the imidazolium region. On the basis of the responses to change in pressure and concentration, two different types of O-H species, i.e., free O-H and bonded O-H, were observed in the O-H stretching region. For [bmim][BF(4)]/water mixtures, the compression leads to loss of the free O-H band intensity. It is likely that free O-H is switched to bonded O-H as high pressures are applied. For [bmim][BF(4)]/methanol mixtures, the free O-H is still stable under high pressures.
Tuberculosis is a serious, worldwide health problem that affects people in many developing countries. The acquired immunodeficiency syndrome epidemic and the development of antibiotic-resistant strains of mycobacteria have contributed to the increasing international incidence of tuberculosis in recent years. Yet, extrapulmonary tuberculosis remains comparatively rare. We present the case of a 44-year-old laborer who complained of bilateral nasal obstruction and postnasal drip for many years. Endoscopic examination disclosed septal perforation with marginal crusting. A biopsy of the marginal tissue was performed and Ziehl-Neelsen staining revealed acid-fast bacilli. Subsequent to a 6-month course of antituberculous medication, the perforation remained, but the crusting subsided.
We have investigated the aggregation behaviors of water molecules in 1-butyl-3-methylimidazolium tetrafluoroborate/ water mixtures using high-pressure methods. Under ambient pressure, the IR spectra indicate that two types of O-H species:freeO-HandbondedO-H,existinginionicliquid/watermixtures.Assampleswerecompressed,acontinuous lossofthefreeO-Hbandintensitywasobserved.Thisobservationmayhavearisenfromchangesinthelocalstructures of water molecules, and the geometrical properties of the hydrogen-bond network are likely to be perturbed as the pressureiselevated.AcomplementaryinsightoftheO-Hspectralfeaturesisobtainedbymeasuringtheconcentrationdependent variation in the mid-infrared spectra under high pressure. A sharp O-H stretching band was observed in a dilutedmixturecorrespondingtothehighorderinaniceVII-likestructure.Nevertheless,averybroadO-Hfeaturewas measuredinaconcentratedmixture,whichmaybeattributedtothepresenceofmorethanonestablecluster.
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