Co-morbid conditions in use of recombinant tissue plasminogen activator (rt-PA) for the treatment of acute ischaemic stroke.

Background: The objective of this study was to characterize the comorbidities in a population of patients with an acute ischaemic stroke, comparing patients that received recombinant tissue plasminogen activator (rt-PA) to those that did not receive rt-PA.

Method: In a retrospective sample of 663 patients admitted for acute ischaemic stroke, this study analysed the effects of co-morbid conditions in the use of rt-PA. It determined non-cerebrovascular risk factors (comorbidities) that differentiate patients who received rt-PA from those who did not receive rt-PA.

Contribution of long-range interactions to the secondary structure of an unfolded globin.

This work explores the effect of long-range tertiary contacts on the distribution of residual secondary structure in the unfolded state of an alpha-helical protein. N-terminal fragments of increasing length, in conjunction with multidimensional nuclear magnetic resonance, were employed. A protein representative of the ubiquitous globin fold was chosen as the model system.

Femtosecond pulse shaping directly in the mid-IR using acousto-optic modulation.

Pulse shaping directly in the mid-IR is accomplished by using a germanium acousto-optic modulator (Ge AOM) capable of programmable phase and amplitude modulation for IR light between 2 and 18 microm. Shaped waveforms centered at 4.9 microm are demonstrated in both the frequency and the time domains.

Heterodyned fifth-order two-dimensional IR spectroscopy: third-quantum states and polarization selectivity.

A heterodyned fifth-order two-dimensional (2D) IR spectrum of a model coupled oscillator system, Ir(CO)(2)(C(5)H(7)O(2)), is reported. The spectrum is generated by a pulse sequence that probes the eigenstate energies up to the second overtone and combination bands, providing a more rigorous potential-energy surface of the coupled carbonyl local modes than can be obtained with third-order spectroscopy. Furthermore, the pulse sequence is designed to generate and then rephase a two-quantum coherence so that the spectrum is line narrowed and the resolution improved for inhomogeneously broadened systems.

Vibrational dynamics of ions in glass from fifth-order two-dimensional infrared spectroscopy.

The vibrational dynamics of the first four antisymmetric stretch vibrational levels of azide in an ionic glass have been measured and correlated using a heterodyned fifth-order two-dimensional infrared pulse sequence. By rephasing a two-quantum coherence, a process not possible with third-order spectroscopy, solvent effects on the frequencies and anharmonicities of the potential energy surface are measured. Fifth-order pulse sequences are another step towards precisely controlling vibrational coherence in analogy to the manipulation of spins in NMR but with ultrafast time resolution.

Heterodyned fifth-order 2D-IR spectroscopy of the azide ion in an ionic glass.

A heterodyned fifth-order infrared pulse sequence has been used to measure a two-dimensional infrared (2D-IR) spectrum of azide in the ionic glass 3KNO3:2Ca(NO3)2. By rephasing a two-quantum coherence, a process not possible with third-order spectroscopy, the 2D-IR spectra are line narrowed, allowing the frequencies, anharmonicities, and their correlations to be measured for the first four (nu=0-3) antisymmetric stretch vibrational levels. In this glass, the vibrational levels are extremely inhomogeneously broadened.

Site-specific vibrational dynamics of the CD3zeta membrane peptide using heterodyned two-dimensional infrared photon echo spectroscopy.

Heterodyned two-dimensional infrared (2D IR) spectroscopy has been used to study the amide I vibrational dynamics of a 27-residue peptide in lipid vesicles that encompasses the transmembrane domain of the T-cell receptor CD3zeta. Using 1-(13)C[Double Bond](18)O isotope labeling, the amide I mode of the 49-Leucine residue was spectroscopically isolated and the homogeneous and inhomogeneous linewidths of this mode were measured by fitting the 2D IR spectrum collected with a photon echo pulse sequence. The pure dephasing and inhomogeneous linewidths are 2 and 32 cm(-1), respectively.

A pulse sequence for directly measuring the anharmonicities of coupled vibrations: Two-quantum two-dimensional infrared spectroscopy.

We have experimentally demonstrated a pulse sequence for the acquisition of heterodyned two-dimensional infrared (2D IR) spectra that correlates the overtone and combination bands to the fundamental frequencies. The spectra are generated by Fourier transforming the time domain signal that is allowed to evolve during one- and two-quantum coherence times. In this manner, the overtone and combination bands appear along the two-quantum axis, resulting in a direct determination of the diagonal and off-diagonal anharmonicities.