Fenske-Hall Approximate Molecular Orbital Analysis of the Chelating Carbene Complex eta5-Cp\u27(CO)Mn{C(OEt)CH2PPh2}

The novel three legged piano stool chelating carbene complex, Cp\u27(CO)Mn{C(OEt)CH2PPh2}, 1, exhibits interesting structural, spectroscopic and electrochemical properties. It also readily undergoes reaction with CO to produce the three legged piano stool complex Cp\u27(CO)2{PPh2C(OEt)=CH2}, 2. This is in contrast to the analogous non-chelating complex Cp(CO)(PPh3)Mn{C(OMe)CH2CH3}, 3, which does not react with CO. This paper discusses the results of Fenske-Hall approximate molecular orbital calculations on model complexes for 1 and 3. The differences in spectroscopic and electrochemical properties are explained using molecular orbital analysis. Possible reasons for the enhanced reactivity of 1are also presented

Molecular Orbital Studies of Nitrosyl Metalloporphyrin Complexes

Molecular orbital calculations are applied to the study of the structure and bonding of nitrosyl metalloporphyrin complexes. The Fenske-Hall approximate molecular orbital method and the Amsterdam Density Functional (ADF) method are used. The calculations provide qualitative and quantitative explanations for the observed structural differences between the nitrosyl porphyrin complexes ofiron, manganese, and cobalt. It is proposed that the energy of the highest occupied molecular orbital (HOMO) of these complexes is primarily responsible for the observed structural differences. The interaction between the nitrosyl ligand and metal dz2 orbital results in an antibonding orbital that is occupied in the complexes of Fe and Co, but unoccupied in the Mn complex. Bending of the metal-N-O linkage in complexes of Fe and Co results in stabilization of this orbital and consequently a more stable configuration for the complex. In addition, the binding affinity of these complexes for a sixth ligand is influenced by the energy and occupation of this largely metal-based orbital. The conclusions drawn from these calculations may provide evidence for the mechanism of activation of the enzyme soluble guanylyl cyclase, which is activated upon binding NO at metal porphyrin site

The percutaneous absorption of soman in a damaged skin porcine model and the evaluation of WoundStat™ as a topical decontaminant

PURPOSE: The aim of this study was to evaluate a candidate haemostat (WoundStat™), down-selected from previous in vitro studies, for efficacy as a potential skin decontaminant against the chemical warfare agent pinacoyl methylfluorophosphonate (Soman, GD) using an in vivo pig model. MATERIALS AND METHODS: An area of approximately 3 cm2 was dermatomed from the dorsal ear skin to a nominal depth of 100 µm. A discrete droplet of 14C-GD (300 µg kg-1) was applied directly onto the surface of the damaged skin at the centre of the dosing site. Animals assigned to the treatment group were given a 2 g application of WoundStat™ 30 s after GD challenge. The decontamination efficacy of WoundStat™ against GD was measured by the direct quantification of the distribution of 14C-GD, as well as routine determination of whole blood cholinesterase and physiological measurements. RESULTS: WoundStat™ sequestered approximately 70% of the applied 14C-GD. Internal radiolabel recovery from treated animals was approximately 1% of the initially applied dose. Whole blood cholinesterase levels decreased to less than 10% of the original value by 15 min post WoundStat™ treatment and gradually decreased until the onset of apnoea or until euthanasia. All treated animals showed signs of GD intoxication that could be grouped into early (mastication, fasciculations and tremor), intermediate (miosis, salivation and nasal secretions) and late onset (lacrimation, body spasm and apnoea) effects. Two of the six WoundStat™ treated animals survived the study duration. CONCLUSIONS: The current study has shown that the use of WoundStat™ as a decontaminant on damaged pig ear skin was unable to fully protect against GD toxicity. Importantly, the findings indicate that the use of WoundStat™ in GD contaminated wounds would not exacerbate GD toxicity. These data suggest that absorbent haemostatic products may offer some limited functionality as wound decontaminants.Peer reviewedFinal Accepted Versio

Density Functional Studies of the Structure and Bonding of Nitrosyl Metalloporphyrin Complexes

Density functional calculations were used to determine optimized geometries fornitrosyl-metalloporphyrin complexes of Fe(II),Co(II)and Mn(II).The optimized structures were found to be consistent with experimental data and previous computational predictions using single point density functional calculations. Vibrational frequencies for the N-0stretching mode were also calculated and shown to be consistent with experimental data. The nature of the bonding between the metal center and nitrosyl ligand is discussed in relation to the structure of the M-N-0 linkage. The results were found to be consistent with previous descriptions derived from the Fenske-Hall approximate molecular orbital method. Other interesting structural features in the optimized geometries are noted

Breeding for improved nitrogen use efficiency in oilseed rape

Oilseed rape has a high requirement for nitrogen (N) fertiliser relative to its seed yield. This paper uses published and unpublished work to explore the extent to which the N use efficiency (seed yield ÷ N supply) of oilseed rape could be improved without reducing seed yield. It was estimated that if the concentration of N in the stem and pod wall at crop maturity could be reduced from 1.0 to 0.6%, the root length density increased to 1 cm/cm3 to 100 cm soil depth and the post flowering N uptake increased by 20 kg N/ha then the fertiliser requirement could be reduced from 191 to 142 kg N/ha and the N use efficiency could be increased from 15.2 to 22.4 kg of seed dry matter per kg N. Genetic variation was found for all of the traits that were estimated to be important for N use efficiency. This indicates that there is significant scope for plant breeders to reduce N use efficiency in oilseed rape

Optimising the analysis of transcript data using high density oligonucleotide arrays and genomic DNA-based probe selection

Background: Affymetrix GeneChip arrays are widely used for transcriptomic studies in a diverse range of species. Each gene is represented on a GeneChip array by a probe-set, consisting of up to 16 probe-pairs. Signal intensities across probe-pairs within a probe-set vary in part due to different physical hybridisation characteristics of individual probes with their target labelled transcripts. We have previously developed a technique to study the transcriptomes of heterologous species based on hybridising genomic DNA (gDNA) to a GeneChip array designed for a different species, and subsequently using only those probes with good homology. Results: Here we have investigated the effects of hybridising homologous species gDNA to study the transcriptomes of species for which the arrays have been designed. Genomic DNA from Arabidopsis thaliana and rice (Oryza sativa) were hybridised to the Affymetrix Arabidopsis ATH1 and Rice Genome GeneChip arrays respectively. Probe selection based on gDNA hybridisation intensity increased the number of genes identified as significantly differentially expressed in two published studies of Arabidopsis development, and optimised the analysis of technical replicates obtained from pooled samples of RNA from rice. Conclusion: This mixed physical and bioinformatics approach can be used to optimise estimates of gene expression when using GeneChip arrays

Longitudinal Study of Relapse From AIDS-Preventive Behavior Among Homosexual Men

There is no viable alternative to the control of AIDS besides prevention; factors contributing to relapse from behaviors presumed to reduce risk of that disease were investigated. The authors studied 524 homosexual men who had refrained from or used condoms during receptive or insertive anal sex (RAS and IAS, respectively) for at least 12 months, contacting them at 6-month intervals thereafter to ascertain current practices. They determined, via interviews, personal traits, appraised stress of maintaining safer sex, mental health, life events, and efforts to cope with potential infection. Negative life events, personal control beliefs, problem-solving abilities, and coping via problem-focused (e.g., seeking a monogamous union) rather than emotion-focused (e.g., "when I need a cure, they will have one") behaviors were associated with RAS, but less so with LAS safer sex behaviors. These findings provide a basis for individual and community-level interventions to change behavior and reduce AIDS risk.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66577/2/10.1177_109019819802500509.pd

Farm Land Ownership as a Source of Retirement Income

Land Economics/Use,