We present three-dimensional diffuse optical tomography of the hemodynamic response to somatosensory stimulation in a rat. These images show the feasibility of volumetrically imaging the functional response to brain activity with diffuse light. A combination of positional optode calibration and contrast-to-noise ratio weighting was found to improve imaging performance.

Neural computations are implemented in densely interconnected networks of excitable neurons as temporal sequences of coactive neuronal ensembles. Ensemble activity is produced by the interaction of external stimuli with internal states but has been difficult to directly study in the past. Currently, high-resolution optical imaging techniques are emerging as powerful tools to investigate neurona...

We report a method to determine the four Stokes parameters of each spectral component in a broadband terahertz (THz) pulse by using a continuously rotating analyzer and a standard THz time domain spectroscopy (THz-TDS) instrument. A complete characterization of the polarization state at each frequency is obtained through a single time-domain measurement. Our method requires no specialized THz e...

Optical activity in 3D-chiral media in the form of circular dichroism and birefringence is a fundamental phenomenon that serves as evidence of life forms and is widely used in spectroscopy. Even in 3D-chiral media exhibiting strong transmission optical activity, the reflective effect is weak and sometimes undetectable. Here we report that specular optical activity at structured interfaces can b...

We demonstrate that engineered artificial gold chiral nanostructures display significant levels of non-linear optical activity even without plasmonic enhancement. Our work suggests that although plasmonic excitation enhances the intensity of second harmonic emission it is not a prerequisite for significant non-linear (second harmonic) optical activity. It is also shown that the non-linear optic...

Background and Objective: Changes of the enzyme acetylcholinesterase are involved in pathogenesis of different nervous disorders including Alzheimer’s disease. This research work was conducted to evaluate the inhibitory effect of Pistacia lentiscus ethanolic extract on acetylcholinesterase activity. Materials and Methods: Activity of the enzyme acetylcholinesterase (AChE) was measured by Ellman...

Thioflavin T (ThT) is amyloid specific fluorescence dye possessing the properties of molecular rotor. We have shown that Thioflavin T forms complexes with non-peptide polyanions heparin, polyadenylate and polystyrene sulphonate by means of absorption spectroscopy. In the presence of chiral polyanions - heparin and polyadenylate - induced optical activity of ThT occurs whereas interaction with a...

Earlier studies in this laboratory (1) and by other workers (Z-4) have suggested that the effect of alkaline pH and urea on myosin resulted in major structural alterations in the molecule. Many of these studies were concerned with the attempt at the isolation of subunits or small polypeptide fragments by the treatment of myosin with high urea concentrations for long periods of time or by exposu...