An Investigation Of Dinuclear Alkylidene-bridged Carbonyl Complexes

The objective of this research was to synthesize binuclear (mu)-alkylidene complexes of manganese or cobalt, to study their chemical properties, and to assess their potential as model intermediates in the Fischer-Tropsch synthesis.;Excess diazoalkane addition to Mn(,2)(CO)(,4)((mu)-CO)((mu)-dppm)(,2) ; dppm = Ph(,2)PCH(,2)PPh(,2), produces 1:1 adducts of formula Mn(,2)(CO)(,4) (mu)-C(O)CHRN(,2) ((mu)-dppm)(,2) (R = H,Me,CO(,2)Et) containing a novel metallacycle derived from coupling of the diazoalkane molecule with a carbonyl ligand. The structure was established by an X-ray analysis of Mn(,2)(CO)(,4) (mu)-C(O)CH(,2)N(,2) ((mu)-dppm)(,2) . Photolysis or thermolysis of each adduct regenerates Mn(,2)(CO)(,4)((mu)-CO)((mu)-dppm)(,2) .;A series of ((mu)-alkylidene)dicobalt complexes was prepared via CO displacement from Co(,2)(CO)(,4)((mu)-CO)(,2)((mu)-dppm) at 25(DEGREES)C by excess diazoalkane addition. Low temperature NMR studies revealed a facile, concerted interconversion from bridging to terminal sites for the bridging units in Co(,2)(CO)(,4)((mu)-CO)((mu)-CH(,2))((mu)-dppm) and Co(,2)(CO)(,4)((mu)-CH(,2))(,2)((mu)-dppm) only.;Carbon-carbon coupling reactions occur at 25(DEGREES)C in reactions of Co(,2)(CO)(,4)((mu)-CH(,2))(,2)((mu)-dppm) with RCCR to give C(,2)H(,4) and Co(,2)(CO)(,4)((mu)-RCCR)((mu)-dppm) (R = CF(,3),Ph), with C(,2)H(,4) to give C(,3)H(,6), and, at 80(DEGREES)C, with H(,2) to yield C(,2)H(,6). Deuterium-labelling studies reveal that the easy methylene coupling reactions to give C(,2)H(,4) from Co(,2)(CO)(,4)((mu)-CH(,2))(,2)((mu)-dppm) involve a complex, intermolecular coupling process associated with a large isotope effect. Addition of CO, SO(,2) or CF(,3)CCCF(,3) to each ((mu)-alkylidene)dicobalt complex induces coupling of the respective alkylidene unit with a carbonyl ligand and subsequent ketene elimination.;Differences in structure and stability noted from the identical diazoalkane additions to the analogous complex Co(,2)(CO)(,4)((mu)-CO)(,2)((mu)-dmpm) ; dmpm = Me(,2)PCH(,2)PMe(,2), were attributed to the higher basicity and smaller steric effects introduced by dmpm versus dppm.;Reaction of the dianionic complexes Co(,2)(CO)(,6)((mu)-L) (\u272)(L = dppm,dmpm) with CH(,2)I(,2) or (alpha),(omega)-diiodoalkanes did not produce the expected dicobaltacycles. The resultant halogen abstraction in each case is suspected to arise from an electron transfer process

The Surgical Management of Acromegaly

Acromegaly is the condition produced by one of the benign tumors of the pituitary gland. These tumors produce a variety of disorders affecting many parts of the body, producing side effects related to abnormal hormone function. The dramatic appearance of the acromegalic giant has attracted attention over the ages. This chapter summarizes the history of the recognition and ultimate diagnosis of acromegaly. The biological and physiological elements are described. The methods of diagnosis and management are elaborated. Although the focus of the chapter is on the surgical approach for treatment, alternative strategies are also discussed, along with the outcomes of management for patients and the restoration of quality of life as a primary goal

Universal Citation and the American Association of Law Libraries: A White Paper

This white paper is a collaborative endeavor of many individuals, including members of the American Association of Law Libraries and its Digital Access to Legal Information Committee (DALIC), formerly the Electronic Legal Information Access & Citation (ELIAC) Committee. First, Justice Yvonne Kauger introduces the topic by identifying the groundbreaking steps taken by the Oklahoma Supreme Court. Law librarians Carol Billings and Kathy Carlson next provide a detailed and comprehensive history of citation reform and the American Association of Law Libraries’ leadership and involvement in the issue. They also summarize the citation reform steps taken in selected jurisdictions. Finally, John Cannan, current DALIC member, provides a look to the future, identifying reasons to advance needed citation reform now

Supplementing sow diets with palm oil during late gestation and lactation; effects on milk production, sow hormonal profiles, and growth and development of her offspring

The supplementing of sow diets with lipids during pregnancy and lactation has been shown to reduce sow condition loss and improve piglet performance. The aim of this study was to determine the effects of supplemental palm oil (PO) on sow performance, plasma metabolites and hormones, milk profiles, and pre-weaning piglet development. A commercial sow ration (C) or an experimental diet supplemented with 10% extra energy in the form of PO, were provided from d 90 of gestation until weaning (24-28 d post-partum) in two groups of 8 multiparous sows. Gestation length of PO sows increased by 1 day (P<0.05). Maternal body weight changes were similar throughout the trial, but loss of backfat during lactation was reduced in PO animals (C: -3.6±0.8 mm; PO: -0.1±0.8 mm; P<0.01). Milk fat was increased by PO supplementation (C d3: 8.0±0.3% fat; PO d3: 9.1±0.3% fat; C d7: 7.8±0.5% fat; PO d7: 9.9±0.5% fat; P<0.05) and hence milk energy yield of PO sows was also elevated (P<0.05). The proportion of saturated fatty acids was greater in colostrum from PO sows (C: 29.19±0.31 g/100g of fat; PO: 30.77±0.36 g/100g of fat; P<0.01). Blood samples taken on 105 days of gestation, within 24 hours of farrowing, day 7 of lactation and at weaning (28 ± 3 days post-farrowing) showed there were no differences in plasma concentrations of triacylglycerol, non-esterified fatty acids, insulin or insulin-like growth factor-1 throughout the trial. However, circulating plasma concentrations of both glucose and leptin were elevated during lactation in PO sows (P< 0.05 and P<0.005, respectively) and thyroxine was greater at weaning in PO sows (P < 0.05). Piglet weight and body composition were similar at birth, as were piglet growth rates throughout the pre-weaning period. Seven days after birth, C piglets contained more body fat, as indicated by their lower fat free mass per kg (C: 66.4±0.8 arbitrary units/kg; PO: 69.7±0.8 arbitrary unit/kg; P<0.01), but by day 14 of life this situation was reversed (C: 65.8±0.6 arbitrary units/kg; PO: 63.6±0.6 arbitrary units/kg; P<0.05). Following weaning, PO sows exhibited an increased ratio of male to female offspring at their subsequent farrowing (C: 1.0±0.3; PO: 2.2±0.2; P<0.05). We conclude that supplementation of sow diets with PO during late gestation and lactation appears to increase sow milk fat content and hence energy supply to piglets. Furthermore, elevated glucose concentrations in the sow during lactation may be suggestive of impaired glucose homeostasis

Accurate, precise modeling of cell proliferation kinetics from time-lapse imaging and automated image analysis of agar yeast culture arrays

BACKGROUND: Genome-wide mutant strain collections have increased demand for high throughput cellular phenotyping (HTCP). For example, investigators use HTCP to investigate interactions between gene deletion mutations and additional chemical or genetic perturbations by assessing differences in cell proliferation among the collection of 5000 S. cerevisiae gene deletion strains. Such studies have thus far been predominantly qualitative, using agar cell arrays to subjectively score growth differences. Quantitative systems level analysis of gene interactions would be enabled by more precise HTCP methods, such as kinetic analysis of cell proliferation in liquid culture by optical density. However, requirements for processing liquid cultures make them relatively cumbersome and low throughput compared to agar. To improve HTCP performance and advance capabilities for quantifying interactions, YeastXtract software was developed for automated analysis of cell array images. RESULTS: YeastXtract software was developed for kinetic growth curve analysis of spotted agar cultures. The accuracy and precision for image analysis of agar culture arrays was comparable to OD measurements of liquid cultures. Using YeastXtract, image intensity vs. biomass of spot cultures was linearly correlated over two orders of magnitude. Thus cell proliferation could be measured over about seven generations, including four to five generations of relatively constant exponential phase growth. Spot area normalization reduced the variation in measurements of total growth efficiency. A growth model, based on the logistic function, increased precision and accuracy of maximum specific rate measurements, compared to empirical methods. The logistic function model was also more robust against data sparseness, meaning that less data was required to obtain accurate, precise, quantitative growth phenotypes. CONCLUSION: Microbial cultures spotted onto agar media are widely used for genotype-phenotype analysis, however quantitative HTCP methods capable of measuring kinetic growth rates have not been available previously. YeastXtract provides objective, automated, quantitative, image analysis of agar cell culture arrays. Fitting the resulting data to a logistic equation-based growth model yields robust, accurate growth rate information. These methods allow the incorporation of imaging and automated image analysis of cell arrays, grown on solid agar media, into HTCP-driven experimental approaches, such as global, quantitative analysis of gene interaction networks