R. A. Sheldon, I. Arends and U. Hanefeld. Green chemistry and catalysis. Wiley-VCH, 2007, 448 pp; ISBN 978-3-527-30715-9 (Hardcover)

Book review

The effects of the fungicides fenhexamid and myclobutanil on SH-SY5Y and U-251 MG human cell lines

Mixtures of pesticides in foodstuffs and the environment are ubiquitous in the developed world and although agents are usually exhaustively tested individually, the toxicological implications of pesticide mixtures are underreported. In this study, the effects of two fungicides, fenhexamid and myclobutanil were investigated individually and in combination on two human cell lines, SH-SY5Y neuronal cells and U-251 MG glial cells. After 48. h of incubation with increasing concentrations of pesticides ranging from 1 to 1000. μM, gene expression profiles were studied in addition to toxicity end points, including cell viability, mitochondrial depolarisation as well as cellular glutathione maintenance. There were no significant differences between the susceptibility of the two cell lines in terms of cell viability assessment or mitochondrial membrane potential, when agents were administered either individually or in combination. By contrast, in the presence of the fungicides, the SH-SY5Y cells showed significantly greater susceptibility to oxidative stress in terms of total thiol depletion in comparison with the astrocytic cells. Treatment with the two pesticides led to significant changes in the cell lines' expression of several genes which regulate cell cycle control and growth (RB1, TIMP1) as well as responses to DNA attrition (ATM and CDA25A) and control of apoptosis (FAS). There was no evidence in this study that the combination of fenhexamid and myclobutanil was significantly more toxic than individual exposure, although gene expression changes suggested there may be differences in the sub-lethal response of both cell lines to both individual and combined exposure.

Corporate governance and the timeliness of corporate internet reporting by U.K. listed companies

This study is an examination of the timeliness of corporate internet reporting by U.K. companies listed on the London Stock Exchange (LSE). The research examines the significance of several corporate governance and firm-specific characteristics as potential determinants of the timeliness of corporate internet reporting. Our primary analysis provides evidence of a significant association between timely corporate internet reporting and the corporate governance characteristics of board experience and board independence. Our findings provide evidence that boards with less cross directorships, more experience in terms of the average age of directors, and lower length in service for executive directors provide more timely corporate internet reporting.We find that board independence is negatively associated with timely corporate internet reporting. Follow-up analysis provides additional evidence of a significant association between the timeliness of corporate internet reporting and board experience. The evidence indicates that role duality and block ownership are associated with less timely corporate internet reporting. Our findings also reveal strengths and weaknesses in the Internet reporting of U.K. listed companies. Companies need to voluntarily focus on improving the timeliness dimension of their corporate internet reporting so that the EU and U.K. accounting regulators do not replace recommendations with regulations.

Corporate governance and the timeliness of corporate internet reporting by U.K. listed companies

This study is an examination of the timeliness of corporate internet reporting by U.K. companies listed on the London Stock Exchange (LSE). The research examines the significance of several corporate governance and firm-specific characteristics as potential determinants of the timeliness of corporate internet reporting. Our primary analysis provides evidence of a significant association between timely corporate internet reporting and the corporate governance characteristics of board experience and board independence. Our findings provide evidence that boards with less cross directorships, more experience in terms of the average age of directors, and lower length in service for executive directors provide more timely corporate internet reporting. We find that board independence is negatively associated with timely corporate internet reporting. Follow-up analysis provides additional evidence of a significant association between the timeliness of corporate internet reporting and board experience. The evidence indicates that role duality and block ownership are associated with less timely corporate internet reporting. Our findings also reveal strengths and weaknesses in the Internet reporting of U.K. listed companies. Companies need to voluntarily focus on improving the timeliness dimension of their corporate internet reporting so that the EU and U.K. accounting regulators do not replace recommendations with regulations. © 2007 Elsevier Inc. All rights reserved.

Big 4 audit fee premiums for national and office-level industry leadership in the United Kingdom

The pricing of Big 4 industry leadership Is examined for a sample of U.K. publicly-listed companies, and adds to the evidence from the Australian and U.S. audit markets that city-specific industry leadership commands a fee premium. There is a significant fee premium for city-specific industry leaders relative to other Big 4 auditors, but no evidence that either the top-ranked or second-ranked firm nationally commands a fee premium relative to other Big 4 auditors, after controlling for city-level industry leadership. We also test for Big 4 fee premiums relative to non-Big 4 auditors and the U.K. data suggest a three-level hierarchy based on audit fee differentials: (1) Big 4 city-specific industry leaders have the largest fees; (2) other Big 4 auditors (noncity leaders) and second-tier national firms have comparable fees that are lower than Big 4 city leaders but larger than third-tier firms; and (3) third-tier accounting firms have the lowest fees.

Deconvolution of magnetic acoustic change complex (mACC)

Objective: The aim of this study was to design a novel experimental approach to investigate the morphological characteristics of auditory cortical responses elicited by rapidly changing synthesized speech sounds. Methods: Six sound-evoked magnetoencephalographic (MEG) responses were measured to a synthesized train of speech sounds using the vowels /e/ and /u/ in 17 normal hearing young adults. Responses were measured to: (i) the onset of the speech train, (ii) an F0 increment; (iii) an F0 decrement; (iv) an F2 decrement; (v) an F2 increment; and (vi) the offset of the speech train using short (jittered around 135. ms) and long (1500. ms) stimulus onset asynchronies (SOAs). The least squares (LS) deconvolution technique was used to disentangle the overlapping MEG responses in the short SOA condition only. Results: Comparison between the morphology of the recovered cortical responses in the short and long SOAs conditions showed high similarity, suggesting that the LS deconvolution technique was successful in disentangling the MEG waveforms. Waveform latencies and amplitudes were different for the two SOAs conditions and were influenced by the spectro-temporal properties of the sound sequence. The magnetic acoustic change complex (mACC) for the short SOA condition showed significantly lower amplitudes and shorter latencies compared to the long SOA condition. The F0 transition showed a larger reduction in amplitude from long to short SOA compared to the F2 transition. Lateralization of the cortical responses were observed under some stimulus conditions and appeared to be associated with the spectro-temporal properties of the acoustic stimulus. Conclusions: The LS deconvolution technique provides a new tool to study the properties of the auditory cortical response to rapidly changing sound stimuli. The presence of the cortical auditory evoked responses for rapid transition of synthesized speech stimuli suggests that the temporal code is preserved at the level of the auditory cortex. Further, the reduced amplitudes and shorter latencies might reflect intrinsic properties of the cortical neurons to rapidly presented sounds. Significance: This is the first demonstration of the separation of overlapping cortical responses to rapidly changing speech sounds and offers a potential new biomarker of discrimination of rapid transition of sound.