Raman spectroscopy provides a powerful, rapid diagnostic tool for the detection of tuberculous meningitis in ex vivo cerebrospinal fluid samples.

In this letter, we propose a novel method for diagnosis of tuberculous meningitis using Raman spectroscopy. The silicate Raman signature obtained from Mycobacterium tuberculosis positive cases enables specific and sensitive detection of tuberculous meningitis from acquired cerebrospinal fluid samples. The association of silicates with the tuberculosis mycobacterium is discussed. We envision that this new method will facilitate rapid diagnosis of tuberculous meningitis without application of exogenous reagents or dyes and can be aptly used as a complementary screening tool to the existing gold standard methods.

Tetra-n-butylammonium borohydride semiclathrate: a hybrid material for hydrogen storage.

In this study, we demonstrate that tetra-n-butylammonium borohydride [(n-C(4)H(9))(4)NBH(4)] can be used to form a hybrid hydrogen storage material. Powder X-ray diffraction measurements verify the formation of tetra-n-butylammonium borohydride semiclathrate, while Raman spectroscopic and direct gas release measurements confirm the storage of molecular hydrogen within the vacant cavities. Subsequent to clathrate decomposition and the release of physically bound H(2), additional hydrogen was produced from the hybrid system via a hydrolysis reaction between the water host molecules and the incorporated BH(4)(-) anions. The additional hydrogen produced from the hydrolysis reaction resulted in a 170% increase in the gravimetric hydrogen storage capacity, or 27% greater storage than fully occupied THF + H(2) hydrate. The decomposition temperature of tetra-n-butylammonium borohydride semiclathrate was measured at 5.7 degrees C, which is higher than that for pure THF hydrate (4.4 degrees C). The present results reveal that the BH(4)(-) anion is capable of stabilizing tetraalkylammonium hydrates.

Laser Raman spectroscopy of THF clathrate hydrate in the temperature range 90-300 K.

In situ Raman and Fourier transform infrared (FTIR-NIR) spectroscopic studies on tetrahydrofuran (THF-C(4)H(8)O) clathrate hydrate (CH) were reported. The Raman results in lattice (64 cm(-1)), ring breathing and C-H stretching mode regions are in conformity with earlier reports, while the FTIR (NIR) studies in second order mode region were reported for the first time. Comparison of the results indicate that the band assigned to ring breathing mode around 922 cm(-1) (in Raman) and corresponding second order mode in NIR around 4295 cm(-1) broadens and shifts in enclathrated THF. The ring breathing mode at lower temperatures (T<120 K) is highly asymmetric and splits into two and are due to different host-guest interactions at lower temperatures.