Synthesis and characterisation of some novel low-coordinate phosphorus compounds containing bulky electron-withdrawing substituents

The synthesis of several new phosphorus derivatives including new monophosphanes of the type RPX(_2) (X = F, CI and H), containing either the Fluoromes [2,4,6-(CF(_3))(_3)C(_6)H(_2)] or Fluoroxyl [2,6-(CF(_3))(_2)C(_6)H(_3)] group has been carried out successfully. The synthesis of a number of Cis-Platin analogous has been facilitated by the reaction of these new monophosphanes with a platinum dimer [(PCl(_2)(Pet(_3))(_2)](_2). These compounds are of the type PtCl(_2)(Pet(_3))RPX(_2) (X = CI, H and F, R = 2,6- bis(trifluoromethyl)phenyl). These compounds have shown an interesting correlation between bond length and (^1)J(_p-pt) NMR coupling. Disubstituted phosphanes (RPX(_2), X = CI, H) have also been synthesised and subsequent reaction has facilitated the formation, characterisation and structure solution of a new phosphorus (I) species (RP(_2)(^(-)))(Ph(_3)PCH(_3))(^1) (R - Fluoromes).Attempts have been made to synthesise the first phosphaalkyne containing a bulky electron withdrawing ligand. This involved the reaction of RP=CCl(_2) (R = 2,6- bis(trifluoromethyl)phenyl) with a number of Pt(0) and Pd(0) species. (^31)P NMR studies have been used extensively throughout the project to help characterise and identify the products. The single crystal, solid state structures of many of the new species were elucidated by X-ray diffraction using a Siemens Smart CCD

Abundance of Bottlenose Dolphins, Tursiops truncatus, in the Coastal Gulf of Mexico

The abundance of bottlenose dolphins (Tursiops truncatus) for many coastal areas of the United States Gulf of Mexico is poorly known. During spring and fall 1987, we used aircraft and strip transects to estimate bottlenose dolphin abundance within 37 km of the U.S. Gulf shore. Greatest estimated dolphin densities were in the north-central Gulf (spring), northern Florida (fall) and Louisiana study areas (fall) (about 0.30 dolphins / km2). We estimated the coastal U.S. Gulf population of bottlenose dolphins to be 16,892 ± 3,628 (95% Cl) and 16,089 ± 3,338 in spring and fall, respectively. Bottlenose dolphins were found throughout the U.S. Gulf waters searched, but herds offshore of Texas were concentrated near passes and Louisiana herds were more common in and near eastern bays. Our estimates are one of the first assessments of the abundance and density of bottlenose dolphins throughout the coastal U.S. Gulf and may provide useful baseline estimates

Biomarkers of subclinical inflammation and increases in glycaemia, insulin resistance and beta-cell function in non-diabetic individuals: the Whitehall II study

Objective: Higher systemic levels of pro-inflammatory biomarkers and low adiponectin are associated with increased risk of type 2 diabetes, but their associations with changes in glycaemic deterioration before onset of diabetes are poorly understood. We aimed to study whether inflammation-related biomarkers are associated with 5-year changes in glucose and insulin, HbA1c, insulin sensitivity and beta-cell function before the diagnosis of type 2 diabetes and whether these associations may be bidirectional. Design and methods: We used multiple repeat measures (17 891 person-examinations from 7683 non-diabetic participants) from the Whitehall II study to assess whether circulating high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL6), IL1 receptor antagonist (IL1Ra) and adiponectin are associated with subsequent changes in glycaemia, insulin, insulin resistance and beta-cell function (based on oral glucose tolerance tests). We examined bidirectionality by testing if parameters of glucose metabolism at baseline are associated with changes in inflammation-related biomarkers. Results: Higher hsCRP and IL6 were associated with increases in fasting insulin, insulin resistance and, for IL6, with beta-cell function after adjustment for confounders. Higher adiponectin was associated with decreases in fasting glucose, HbA1c, fasting insulin, insulin resistance and beta-cell function. The reverse approach showed that 2-h glucose and insulin sensitivity were associated with changes in IL1Ra. Fasting insulin and insulin resistance showed inverse associations with changes in adiponectin. Conclusions: Subclinical inflammation is associated with development of increased glycaemia, insulin resistance and beta-cell function in non-diabetic individuals. These findings are consistent with the hypothesis that inflammation-related processes may increase insulin resistance and lead to a compensatory upregulation of beta-cell function

The microbial ferrous wheel in a neutral pH groundwater seep

Evidence for microbial Fe redox cycling was documented in a circumneutral pH ground-water seep near Bloomington, Indiana. Geochemical and microbiological analyses were conducted at two sites, a semi-consolidated microbial mat and a floating puffball structure. In situ voltammetric microelectrode measurements revealed steep opposing gradients of o2 and Fe(I I) at both sites, similar to other groundwater seep and sedimentary environments known to support microbial Fe redox cycling. The puffball structure showed an abrupt increase in dissolved Fed I) just at its surface (~5cm depth), suggesting an internal Fe(I I) source coupled to active Fed 1I) reduction. Most probable number enumerations detected microaerophilic Fe(II)-oxidizing bacteria (FeoB) and dissimilatory Fe(III)-reducing bacteria (FeRB) at densities of 102 to 105 cells ml_~1 in samples from both sites. In vitro Fed 1I) reduction experiments revealed the potential for immediate reduction (no lag period) of native Fe(III) oxides. Conventional full-length 16S rRNA gene clone libraries were compared with high throughput barcode sequencing of theV1, V4, orV6 variable regions of 16S rRNA genes in order to evaluate the extent to which new sequencing approaches could provide enhanced insight into the composition of Fe redox cycling microbial community structure. The composition of the clone libraries suggested a lithotroph-dominated microbial community centered around taxa related to known FeoB (e.g., Gallionella, Sideroxydans, Aquabacterium). Sequences related to recognized FeRB (e.g., Rhodoferax, Aeromonas, Geobacter, Desulfovibrio) were also well-represented. overall, sequences related to known FeoB and FeRB accounted for 88 and 59% of total clone sequences in the mat and puffball libraries, respectively. Taxa identified in the barcode libraries showed partial overlap with the clone libraries, but were not always consistent across different variable regions and sequencing platforms. However, the barcode libraries provided confirmation of key clone library results (e.g., the predominance of Betaproteobacteria) and an expanded view of lithotrophic microbial community composition

Diclofenac Prolongs Repolarization in Ventricular Muscle with Impaired Repolarization Reserve

Background: The aim of the present work was to characterize the electrophysiological effects of the non-steroidal anti- inflammatory drug diclofenac and to study the possible proarrhythmic potency of the drug in ventricular muscle. Methods: Ion currents were recorded using voltage clamp technique in canine single ventricular cells and action potentials were obtained from canine ventricular preparations using microelectrodes. The proarrhythmic potency of the drug was investigated in an anaesthetized rabbit proarrhythmia model. Results: Action potentials were slightly lengthened in ventricular muscle but were shortened in Purkinje fibers by diclofenac (20 mM). The maximum upstroke velocity was decreased in both preparations. Larger repolarization prolongation was observed when repolarization reserve was impaired by previous BaCl 2 application. Diclofenac (3 mg/kg) did not prolong while dofetilide (25 mg/kg) significantly lengthened the QT c interval in anaesthetized rabbits. The addition of diclofenac following reduction of repolarization reserve by dofetilide further prolonged QT c . Diclofenac alone did not induce Torsades de Pointes ventricular tachycardia (TdP) while TdP incidence following dofetilide was 20%. However, the combination of diclofenac and dofetilide significantly increased TdP incidence (62%). In single ventricular cells diclofenac (30 mM) decreased the amplitude of rapid (I Kr ) and slow (I Ks ) delayed rectifier currents thereby attenuating repolarization reserve. L-type calcium current (I Ca ) was slightly diminished, but the transient outward (I to ) and inward rectifier (I K1 ) potassium currents were not influenced. Conclusions: Diclofenac at therapeutic concentrations and even at high dose does not prolong repolarization markedly and does not increase the risk of arrhythmia in normal heart. However, high dose diclofenac treatment may lengthen repolarization and enhance proarrhythmic risk in hearts with reduced repolarization reserve

An absorbing boundary formulation for the stratified, linearized, ideal MHD equations based on an unsplit, convolutional perfectly matched layer

Perfectly matched layers are a very efficient and accurate way to absorb waves in media. We present a stable convolutional unsplit perfectly matched formulation designed for the linearized stratified Euler equations. However, the technique as applied to the Magneto-hydrodynamic (MHD) equations requires the use of a sponge, which, despite placing the perfectly matched status in question, is still highly efficient at absorbing outgoing waves. We study solutions of the equations in the backdrop of models of linearized wave propagation in the Sun. We test the numerical stability of the schemes by integrating the equations over a large number of wave periods.Comment: 8 pages, 7 figures, accepted, A &

Meat eating and nutritional quality of lambs sired by high and low muscle density rams

Intramuscular fat (IMF) content affects eating and nutritional quality of lamb meat. Muscle density measured by computer tomography is an in vivo proxy measure of IMF content that affects eating and nutritional quality of lamb meat. Lambs sired by high muscle density (HMD) or low muscle density (LMD) rams, selected for slaughter on commercial criteria were measured for meat quality and nutritional traits. A restricted maximum likelihood model was used to compare lamb traits. Additionally, regression analysis of sire estimated breeding value (EBV) for muscle density was performed for each meat quality trait. Muscle density EBV had a negative regression with IMF content (P < 0.001). For each unit increase in muscle density EBV, there was a significant decrease in loin (− 1.69 mg/100 g fresh weight) and topside IMF (− 0.03 mg/100 g fresh weight). Muscle density EBV had a negative regression with grouped saturated and monounsaturated fatty acids concentration (and monounsaturated proportion P < 0.001). Muscle density EBV had a negative regression with loin sensory traits tenderness, juiciness and overall liking and many novel tenderness sensory traits measured (P < 0.05). Selecting for LMD EBV increased IMF content and favourable meat eating quality traits. In contrast, sire muscle density EBV had a positive regression with loin polyunsaturated:saturated fat ratio and grouped polyunsaturated proportion traits (including total polyunsaturated proportion, total omega-6 (n-6) and total omega-3 (n-3) fatty acids (P < 0.001). This is explained by the fact that as sire muscle density EBV increases, polyunsaturated fatty acid proportion increases and the proportion of saturated and monounsaturated fatty acid content decreases. Muscle density EBV had a positive regression with shear force and the novel toughness sensory traits (P < 0.05). Selection for HMD EBV's increased shear force and toughness traits, which is unfavourable for the consumer. Low muscle density sired meat had higher meat colour traits chroma/saturation (+ 0.64, SD 2.30, P = 0.012), redness (+ 0.52, SD 1.91, P = 0.012) and yellowness (+ 0.31, SD 1.49, P = 0.08) compared to HMD sired meat. Selection for LMD could be used within a breeding programme to increase IMF content and enhance both meat colour and improve eating quality parameters