Proton-Coupled Electron Transfer Reactions with Photometric Bases Reveal Free Energy Relationships for Proton Transfer

The proton-coupled electron transfer (PCET) oxidation of p-aminophenol in acetonitrile was initiated via stopped-flow rapid-mixing and spectroscopically monitored. For oxidation by ferrocenium in the presence of 7-(dimethylamino)quinoline proton acceptors, both the electron transfer and proton transfer components could be optically monitored in the visible region; the decay of the ferrocenium absorbance is readily monitored (λmax = 620 nm), and the absorbance of the 2,4-substituted 7-(dimethylamino)quinoline derivatives (λmax = 370-392 nm) red-shifts substantially (ca. 70 nm) upon protonation. Spectral analysis revealed the reaction proceeds via a stepwise electron transfer-proton transfer process, and modeling of the kinetics traces monitoring the ferrocenium and quinolinium signals provided rate constants for elementary proton and electron transfer steps. As the pKa values of the conjugate acids of the 2,4-R-7-(dimethylamino)quinoline derivatives employed were readily tuned by varying the substituents at the 2- and 4-positions of the quinoline backbone, the driving force for proton transfer was systematically varied. Proton transfer rate constants (kPT,2 = (1.5-7.5) × 10(8) M(-1) s(-1), kPT,4 = (0.55-3.0) × 10(7) M(-1) s(-1)) were found to correlate with the pKa of the conjugate acid of the proton acceptor, in agreement with anticipated free energy relationships for proton transfer processes in PCET reactions

Habitat Destruction by Collectors Associated with Decreased Abundance of Rock-Dwelling Lizards

Declines in biodiversity caused by habitat loss have been well documented on large spatial scales, however, effects of habitat loss on small scales have received little attention. Some common methods of reptile collection, primarily for commercial harvest, result in destruction of cracks, crevices, and other cool, moist microhabitats in desert rock outcrops. We developed a method for identifying habitat destruction associated with reptile collecting. We surveyed lightly and heavily disturbed areas near Phoenix, Arizona to determine if microhabitat loss caused by collectors was associated with decreased relative abundance of reptiles. Of four diurnal lizard species studied, relative abundance of two rock-dwelling species was negatively correlated with level of microhabitat destruction, whereas relative abundance of one ground-dwelling species and one habitat generalist species was not. Habitat destruction caused by collectors may have negative effects, not only at the individual level, but at the population and community levels as well. We recommend regulation of commercial trade in reptiles; disallowing collecting activities that cause habitat damage; increased law enforcement; and educational programs directed primarily at novice collectors

Neurophysiology

Contains research objectives and summary of research on seventeen research projects and reports on four research projects.National Institutes of Health (Grant 5 TOl EY00090-02)Bell Telephone Laboratories, Inc. (Grant)National Institutes of Health (Grant 5 ROI EY01149-03)National Institutes of Health (Grant NS 12307-01)National Institutes of Health (Grant 1 K04 NS00010

Integrated genomics and proteomics define huntingtin CAG length-dependent networks in mice.

To gain insight into how mutant huntingtin (mHtt) CAG repeat length modifies Huntington's disease (HD) pathogenesis, we profiled mRNA in over 600 brain and peripheral tissue samples from HD knock-in mice with increasing CAG repeat lengths. We found repeat length-dependent transcriptional signatures to be prominent in the striatum, less so in cortex, and minimal in the liver. Coexpression network analyses revealed 13 striatal and 5 cortical modules that correlated highly with CAG length and age, and that were preserved in HD models and sometimes in patients. Top striatal modules implicated mHtt CAG length and age in graded impairment in the expression of identity genes for striatal medium spiny neurons and in dysregulation of cyclic AMP signaling, cell death and protocadherin genes. We used proteomics to confirm 790 genes and 5 striatal modules with CAG length-dependent dysregulation at the protein level, and validated 22 striatal module genes as modifiers of mHtt toxicities in vivo

Gonadal Transcriptome Alterations in Response to Dietary Energy Intake: Sensing the Reproductive Environment

Reproductive capacity and nutritional input are tightly linked and animals' specific responses to alterations in their physical environment and food availability are crucial to ensuring sustainability of that species. We have assessed how alterations in dietary energy intake (both reductions and excess), as well as in food availability, via intermittent fasting (IF), affect the gonadal transcriptome of both male and female rats. Starting at four months of age, male and female rats were subjected to a 20% or 40% caloric restriction (CR) dietary regime, every other day feeding (IF) or a high fat-high glucose (HFG) diet for six months. The transcriptional activity of the gonadal response to these variations in dietary energy intake was assessed at the individual gene level as well as at the parametric functional level. At the individual gene level, the females showed a higher degree of coherency in gonadal gene alterations to CR than the males. The gonadal transcriptional and hormonal response to IF was also significantly different between the male and female rats. The number of genes significantly regulated by IF in male animals was almost 5 times greater than in the females. These IF males also showed the highest testosterone to estrogen ratio in their plasma. Our data show that at the level of gonadal gene responses, the male rats on the IF regime adapt to their environment in a manner that is expected to increase the probability of eventual fertilization of females that the males predict are likely to be sub-fertile due to their perception of a food deficient environment

Determinants and Effects on Property Values of Participation in Voluntary Cleanup Programs: The Case of Colorado

State Voluntary Cleanup Programs (VCPs) were established starting in the 1990s to encourage the environmental remediation and redevelopment of contaminated properties. These programs typically offer liability relief, subsidies and other regulatory incentives in exchange for site cleanup. This paper asks three questions: First, what type of properties are attracted to voluntary cleanup programs? Second, what is the interaction between these state programs and other incentives for remediation and economic development, such as Enterprise Zone and Brownfield Zone designations? Third, what is the effect of participation in the VCP on property values? We use data from Colorado’s VCP to answer these questions. We find that most of the properties enrolled in this program were not previously listed on EPA’s contaminated site registries, and that most applicants seek to obtain directly a “no further action” determination without undergoing remediation. The main determinants of participation are the size of the parcel and whether the surrounding land use is primarily residential, while other incentives have little effect. Properties with confirmed contamination sell at a 47% discount relative to comparable uncontaminated parcels, and participation tends to raise the property price, but this latter effect is not statistically significant. Taken together, these findings suggest that the participating properties are those with high development potential, and hint at the possibility that owners or developers may be seeking to obtain a clean bill of health from the State with only minimal or no cleanup efforts. Were these findings confirmed with data from other states, they would raise doubts about the effectiveness of voluntary programs in encouraging remediation and their usefulness in reversing some of the undesired effects of the Superfund legislation

Voluntary Cleanups and Redevelopment Potential: Lessons from Baltimore, Maryland

Policy has increasingly shifted towards economic incentives and liability attenuation for promoting cleanup and redevelopment of contaminated sites, but little is known about the effectiveness of such policies. An example of such legislation is State Voluntary Cleanup Programs (VCPs), which were established in the US in the 1990s and to date have been implemented in almost every state. We examine Baltimore properties that participated in the Maryland VCP from its inception in 1997 to the end of 2006. Specifically, we examine what type of properties tend to participate in these programs, how these properties compare to other eligible but non-participating sites, and what is the redevelopment potential of VCP properties and implications towards open space conversion. We find that most applicants (66%) actually requested a No Further Action Determination directly, rather than proposing cleanup. VCP properties tend to be industrial, located in industrial areas, and away from residential neighborhoods. In more recent years larger industrial properties have increasingly enrolled in the program. The majority of sites are reused as industrial or commercial. In contrast to Alberini (2007), this suggests that pressure for residential development does not drive VCP participation. Based on differences in zoning requirements, the VCP may reduce demand for potentially contaminating activities on pristine land by as much as 1,238 to 6,444 acres, in Baltimore alone

Head and Neck Cancer: United Kingdom National Multidisciplinary Guidelines, Sixth Edition.

This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited