Spatial and temporal variablity of nonmethane hydrocarbon mixing ratios and their relation to photochemical lifetime

The relationship between temporal and spatial variability of C2-C8 nonmethane hydrocarbon mixing ratios and their HO lifetimes (τ) is presented for samples collected during the 1993 North Atlantic Regional Experiment (NARE) and from other urban and remote sites. The C2-C4 alkanes, acetylene and benzene typically define a trend of the form slnx=Aτ-b where slnx is the standard deviation of the ln of the mixing ratio. The relationship extended over a wider range of hydrocarbons in winter. The exponent b ranged in value from 0.2±0.023 for winter urban data where C2-C8 hydrocarbons defined a strongly correlated trend, to 0.56±0.15 for C2-C4 hydrocarbons at a coastal site in Nova Scotia during NARE. The trends are significantly different from that given by the Junge relationship [Junge, 1974]. Data from the Azores do not display such a trend and were likely influenced by local emissions. Variance trends are a useful analytical tool for examining the validity of hydrocarbon measurements

Optimal selection and ordering of columns in supersaturated designs

Two methods to select columns for assigning factors to work on supersaturated designs are proposed. The focus of interest is the degree of non-orthogonality between the selected columns. One method is the exhaustive enumeration of selections of p columns from all k columns to find the exact optimality, while the other is intended to find an approximate solution by applying techniques used in the corresponding analysis, aiming for ease of use as well as a reduction in the large computing time required for large k with the first method. Numerical illustrations for several typical design matrices reveal that the resulting “approximately” optimal assignments of factors to their columns are exactly optimal for any p. Ordering the columns in E(s2)-optimal designs results in promising new findings including a large number of E(s2)-optimal designs

Probing Electron Tunneling Pathways: Electrochemical Study of Rat Heart Cytochromecand Its Mutant on Pyridine-Terminated SAMs

The electron-transfer rates between gold electrodes and adsorbed cytochromes are compared for native cytochrome c and its mutant (K13A) using two different immobilization strategies. A recent study by Niki (Niki, K.; Hardy, W. R.; Hill, M. G.; Li, H.; Sprinkle, J. R.; Margoliash, E.; Fujita, K.; Tanimura, R.; Nakamura, N.; Ohno, H.; Richards, J. H.; Gray, H. B. J. Phys. Chem. B 2003, 107, 9947) showed that the electron-transfer rate for a particular mutant cytochrome c (K13A) is orders of magnitude slower than the native form when electrostatically adsorbed on SAM-coated gold electrodes. The current study directly “links” the protein's heme unit to the SAM, thereby “short circuiting” the electron tunneling pathway. These findings demonstrate that the immobilization strategy can modify the electron-transfer rate by changing the tunneling pathway

The association of childhood maltreatment with depression and anxiety is not moderated by the oxytocin receptor gene

Background: The oxytocin receptor (OXTR) gene may be involved in resilience or vulnerability towards stress, and hence in the development of stress-related disorders. There are indications that OXTR single nucleotide polymorphisms (SNPs) interact with early life stressors in predicting levels of depression and anxiety. To replicate and extend these findings, we examined whether three literature-based OXTR SNPs (rs2254298, rs53576, rs2268498) interact with childhood maltreatment in the development of clinically diagnosed depression and anxiety disorders. Methods: We included 2567 individuals from the Netherlands Study of Depression and Anxiety. This sample consisted of 387 healthy controls, 428 people with a current or past depressive disorder, 243 people with a current or past anxiety disorder, and 1509 people with both lifetime depression and anxiety diagnoses. Childhood maltreatment was measured with both an interview and via self-report. Additional questionnaires measured depression and anxiety sensitivity. Results: Childhood maltreatment was strongly associated with both lifetime depression and anxiety diagnoses, as well as with depression and anxiety sensitivity. However, the OXTR SNPs did not moderate these associations nor had main effects on outcomes. Conclusions: The three OXTR gene SNPs did not interact with childhood maltreatment in predicting lifetime depression and anxiety diagnoses or sensitivity. This stresses the importance of replication studies with regard to OXTR gene variants in general populations as well as in clearly established clinical samples

Organometallic nucleoside analogues with ferrocenyl linker groups: Synthesis and cancer cell line studies

Examples of organometallic compounds as nucleoside analogues are rare within the field of medicinal bioorganometallic chemistry. We report on the synthesis and properties of two chiral ferrocene derivatives containing a nucleobase and a hydroxyalkyl group. These so-called ferronucleosides show promising anticancer activity, with cytostatic studies on five different cancer cell lines indicating that both functional groups are required for optimal activity.status: publishe