Investigating neuromagnetic brain responses against chromatic flickering stimuli by wavelet entropies

BACKGROUND: Photosensitive epilepsy is a type of reflexive epilepsy triggered by various visual stimuli including colourful ones. Despite the ubiquitous presence of colorful displays, brain responses against different colour combinations are not properly studied. METHODOLOGY/PRINCIPAL FINDINGS: Here, we studied the photosensitivity of the human brain against three types of chromatic flickering stimuli by recording neuromagnetic brain responses (magnetoencephalogram, MEG) from nine adult controls, an unmedicated patient, a medicated patient, and two controls age-matched with patients. Dynamical complexities of MEG signals were investigated by a family of wavelet entropies. Wavelet entropy is a newly proposed measure to characterize large scale brain responses, which quantifies the degree of order/disorder associated with a multi-frequency signal response. In particular, we found that as compared to the unmedicated patient, controls showed significantly larger wavelet entropy values. We also found that Renyi entropy is the most powerful feature for the participant classification. Finally, we also demonstrated the effect of combinational chromatic sensitivity on the underlying order/disorder in MEG signals. CONCLUSIONS/SIGNIFICANCE: Our results suggest that when perturbed by potentially epileptic-triggering stimulus, healthy human brain manages to maintain a non-deterministic, possibly nonlinear state, with high degree of disorder, but an epileptic brain represents a highly ordered state which making it prone to hyper-excitation. Further, certain colour combination was found to be more threatening than other combinations

Photodynamic therapy for endodontic treatment of primary teeth: Original research article

Background: Tooth decay and traumatic dental injuries are the main causes of pulp inflammation in primary teeth. The present study was conducted on photodynamic therapy for endodontic treatment of primary teeth. Materials & Methods: 40 primary anterior teeth with pulp necrosis were divided into 2 groups: Group I, conventional root canal therapy and group II, conventional root canal therapy combined with antimicrobial PDT. Each group with 20 patients. Microbiological samples of the intra-canal content were taken using paper cones. Results: Group I & II had 19 boys and 9 girls and 8 boys and 12 girls respectively. Colony-forming units (CFU/mL) before and after treatment in group I at sample 1, 2, 3, 4, 5, 6, 7, 8, 9& 10 were 94000 and 0, 87040 and 2433, 14530 and 0,154231 and 4500, 123145 and 3200, 28453 and 550, 110232 and 1250,112456 and 3100, 43294 and 0 and 142945 and 1955 respectively. CFU before and after treatment in group II at sample 1,2,3,4,5,6,7,8,9 &10 were 194000 and 248,187040 and 2450,24530 and 0, 254231 and 4200,23140 and 300,38453 and 430,120232 and 1280, 212438 and 3600,143294 and 0 and 242940 and 1924 respectively. Conclusion: Conventional treatment combined with antimicrobial PDT found to be equall

Client-firm market reaction to regulatory action against a major accounting firm

This study assesses the audit client firm share price reactions to a disclosure that the California State Board of Accountancy considered revoking Ernst & Young\u27s (E&Y) license to practice in California due to alleged gross negligence in the Lincoln Savings and Loan fraud scandal. The insurance hypothesis and/or the audit quality explanation justify the expectation of significant client-firm share price reactions. We find limited empirical support that the disclosure of the revocation event is associated with negative market responses for E&Y\u27s clients. Results also indicate that auditor-supplied insurance and audit quality are more important for client firms experiencing financial distress, higher growth rates, and higher return variability