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Elements are produced in stars through a variety of processes; some are well known, others are still the object of active research. The elements zirconium (Zr) and yttrium (Y) reside in the mass range where there is uncertainty about the production mechanism at early time. The rapid n-capture process (r-process) was believed to be responsible for the production, but no study has been able to successfully use the r-process to reproduce the abundance signature for elements in this mass range for metal-poor halo stars. It has been suggested that there may be an undiscovered component to the r-process. We have performed new abundance calculations for the elements Y and Zr in six metal-poor halo giants, using high-quality spectra, and in the case of Zr, new atomic data. Our results are consistent with previous authors' analysis of these stars, but with reduced values for the uncertainty, due to new laboratory data and better quality observational data. Comparison of the lighter n-capture elements' abundances to those of the heavier s-process element barium (Ba) show that there is no correlation between the production of the light elements to the heavy elements. This indicates that there seem to be a multiplicity of processes operating early in the history of the Galaxy. Our results suggest that the main r-process is responsible for production of the elements from Ba onward in atomic number, while some as yet unknown process (or processes) is responsible for the production of the lighter n-capture elements.

The upregulation of a limited number of growth factors in our interferon-gamma transgenic model for regeneration within the pancreas lead us to propose that these factors are important during pancreatic regeneration. In this study, we have assessed the influence of two growth factors within the pancreas, epidermal growth factor (EGF) and keratinocyte growth factor (KGF), by ectopically expressing these proteins under the control of the human insulin promoter in transgenic mice. This beta-cell-targeted expression of either EGF or KGF resulted in significant morphological changes, including cellular proliferation and disorganized islet growth. Intercrossing the individual Ins-EGF and Ins-KGF transgenic mice resulted in more profound changes in pancreatic morphology including proliferation of pancreatic cells and extensive intra-islet fibrosis. Insulin-producing beta-cells were found in some of the ducts of older Ins-EGF and Ins-EGFxKGF transgenic mice, and amylase-producing cells were observed within the islet structures of the double transgenic mice. These data suggest that both EGF and KGF are capable of affecting pancreatic differentiation and growth, and that co-expression of these molecules in islets has a more substantial impact on the pancreas than does expression of either growth factor alone.

Keratinocyte growth factor, (KGF), a member of the fibroblast growth factor (FGF) family, is involved in wound healing. It also promotes the differentiation of many epithelial tissues and proliferation of epithelial cells as well as pancreatic duct cells. Additionally, many members of the highly homologous FGF family (including KGF), influence both growth and cellular morphology in the developing embryo. We have previously observed elevated levels of KGF in our interferon-gamma transgenic mouse model of pancreatic regeneration. To understand the role of KGF in pancreatic differentiation, we generated insulin promoter-regulated KGF transgenic mice. Remarkably, we have found that ectopic KGF expression resulted in the emergence of hepatocytes within the islets of Langerhans in the pancreas. Additionally, significant intra-islet duct cell proliferation in the pancreata of transgenic KGF mice was observed. The unexpected appearance of hepatocytes and proliferation of intra-islet duct cells in the pancreata of these mice evidently stemmed directly from local exposure to KGF.

Water column dissolved inorganic carbon and total alkalinity were measured during five hydrographic sections in the Atlantic Ocean and Drake Passage. The work was funded through the Strategic Funding Initiative of the UK's Oceans2025 programme, which ran from 2007 to 2012. The aims of this programme were to establish the regional budgets of natural and anthropogenic carbon in the North Atlantic, the South Atlantic, and the Atlantic sector of the Southern Ocean, as well as the rates of change of these budgets. This paper describes in detail the dissolved inorganic carbon and total alkalinity data collected along east–west sections at 47° N to 60° N, 24.5° N, and 24° S in the Atlantic and across two Drake Passage sections. Other hydrographic and biogeochemical parameters were measured during these sections, and relevant standard operating procedures are mentioned here. Over 95% of dissolved inorganic carbon and total alkalinity samples taken during the 24.5° N, 24° S, and the Drake Passage sections were analysed onboard and subjected to a first-level quality control addressing technical and analytical issues. Samples taken along 47° N to 60° N were analysed and subjected to quality control back in the laboratory. Complete post-cruise second-level quality control was performed using cross-over analysis with historical data in the vicinity of measurements, and data were submitted to the CLIVAR and Carbon Hydrographic Data Office (CCHDO), the Carbon Dioxide Information Analysis Center (CDIAC) and and will be included in the Global Ocean Data Analyses Project, version 2 (GLODAP 2), the upcoming update of Key et al. (2004).

The influence of the island mass effect of South Georgia on the seasonal marine carbon cycle was investigated during austral summer (January-February) 2008. South Georgia (54-55 degrees S 36-38 degrees W) lies on the North Scotia Ridge, strongly influencing the passage of the Southern Antarctic Circumpolar Current Front to the south. Surface waters upstream of the island, in the central Scotia Sea, were characterised by relative high-nutrient low-chlorophyll (HNLC) conditions from winter (September) 2007 to summer, as indicated by satellite and shipboard observations. The fugacity of carbon dioxide (fCO(2)) was slightly supersaturated and the HNLC waters represented a summertime CO2 source of 2.6 +/- 1.5 mmol m(-2) day(-1). Extensive phytoplankton blooms developed in the Georgia Basin, downstream of South Georgia, in October 2007 and persisted until March 2008. The seasonal depletion in dissolved inorganic carbon (DIC) was 94 +/- 1 mu mol kg(-1) and the Delta fCO(2)(sea-air) was -92 +/- 21 mu atm in the core of the bloom by early February. These conditions created a strong sink for atmospheric CO2 of -12.9 +/- 11.7 mmol m(-2) day(-1). In contrast, wintertime mixing into DIC-rich sub-surface waters created a strong CO2 source of 22.0 +/- 14.4 mmol m(-2) day(-1). These processes drive substantial seasonal changes in DIC of up to -0.7 mu mol kg(-1) day(-1) from winter to summer. Similarly to the blooms of Kerguelen and Crozet, the South Georgia bloom is likely to be fuelled by natural iron fertilisation. A DIC deficit of 2.2 +/- 0.3 mol m(-2) upstream of South Georgia suggested that the relative HNLC waters were more productive than indicated by satellites. The DIC deficit more than doubled downstream of South Georgia (4.6 +/- 0.8 mol m(-2)) to create the strongest seasonal carbon uptake in ice-free waters of the Southern Ocean to date.

The effect of sea ice melt on the carbonate chemistry of surface waters in the Weddell–Scotia Confluence, Southern Ocean, was investigated during January 2008. Contrasting concentrations of dissolved inorganic carbon (DIC), total alkalinity (TA) and the fugacity of carbon dioxide ( f CO 2 ) were observed in and around the receding sea ice edge. The precipitation of carbonate minerals such as ikaite (CaCO 3 ·6H 2 O) in sea ice brine has the net effect of decreasing DIC and TA and increasing the f CO 2 in the brine. Deficits in DIC up to 12 ± 3 μmol kg -1 in the marginal ice zone (MIZ) were consistent with the release of DIC-poor brines to surface waters during sea ice melt. Biological utilization of carbon was the dominant processes and accounted for 41 ± 1 μmol kg -1 of the summer DIC deficit. The data suggest that the combined effects of biological carbon uptake and the precipitation of carbonates created substantial undersaturation in f CO 2 of 95 μatm in the MIZ during summer sea ice melt. Further work is required to improve the understanding of ikaite chemistry in Antarctic sea ice and its importance for the sea ice carbon pump. DOI: 10.1111/j.1600-0889.2010.00496.x

Cadmium, copper, iron, and zinc levels were measured in the kidneys of 115 grey wolves (Canis lupus) from Idaho, Montana and Alaska (United States), and from the Northwest Territories (Canada). No significant differences in the levels of iron or copper were observed between locations, but wolf kidneys from more northern locations had significantly higher cadmium levels (Alaska > Northwest Territories > Montana ≈ Idaho), and wolves from Alaska showed significantly higher zinc than other locations. Additionally, female wolves in Alaska had higher iron levels than males, and adult wolves in Montana had higher copper levels than subadults.

Basic fibroblast growth factor (FGF-2) is posttranslationally modified by the enzymatic transfer of ADP-ribose from nicotinamide adenine dinucleotide (NAD). When sonicated nuclei of adrenal capillary endothelial or SK-Hep1 cells are incubated with [32P]NAD, FGF-2 is rapidly ADP-ribosylated in a dose- and time-dependent fashion. Proteins structurally related to FGF-2 (FGF-6 and -7) are readily modified, suggesting that they share a common substrate motif. Yet, FGF-1, the most structurally homologous member of the FGF family, is a poor substrate. The reaction is also specific; interleukin-1 alpha, transforming growth factor-alpha, nerve growth factor, insulin-like growth factor-I, and granulocyte macrophage-colony stimulating factor are not substrates for ribosylation. Because the ADP ribosylation of FGF-2 is acid resistant but base and hydroxylamine sensitive, the linkage appears to be mediated through arginine. Most importantly, however, we also establish that endogenous FGF-2 is a substrate for ribosylation. As such, an immunoreactive ADP-ribosylated FGF-2 is detected in extracts of SK-Hep1 nuclei when they are incubated with [32P]NAD. Taken together, these findings suggest that the role played by ADP ribosylation in signal transduction, DNA repair, the control of the cell cycle, and cell differentiation may involve its ability to target molecules such as FGF-2.

To identify the source(s) of carbon for the indirect pathway of hepatic glycogen synthesis, we studied nine 42-h fasted conscious dogs given a continuous intraduodenal infusion of glucose, labeled with [1-13C]glucose and [3-3H]glucose, at 8 mg.kg-1.min-1 for 240 min. Glycogen formation by the direct pathway was measured by 13C-NMR. Net hepatic balances of glucose, gluconeogenic amino acids, lactate, and glycerol were determined using the arteriovenous difference technique. During the steady-state period (the final hour of the infusion), 81% of the glucose infused was absorbed as glucose. Net gut output of lactate and alanine accounted for 5% and 3% of the glucose infused, respectively. The cumulative net hepatic uptakes were: glucose, 15.5 +/- 3.8 g; gluconeogenic amino acids, 32.2 +/- 2.2 mmol (2.9 +/- 0.2 g of glucose equivalents); and glycerol, 6.1 +/- 0.9 mmol (0.6 +/- 0.1 g of glucose equivalents). The liver produced a net of 29.2 +/- 9.6 mmol of lactate (2.6 +/- 0.8 g of glucose equivalents). Net hepatic glycogen synthesis totaled 9.3 +/- 2.5 g (1.8 +/- 0.4 g/100 g liver), with the direct pathway being responsible for 57 +/- 10%. Thus, net hepatic glucose uptake was sufficient to account for all glycogen formed by both the direct and indirect pathways. Total net hepatic uptake of gluconeogenic precursors (gluconeogenic amino acids, glycerol, and lactate) was able to account for only 20% of net glycogen synthesis by the indirect pathway. In a net sense, our data are consistent with an intrahepatic origin for most of the three-carbon precursors used for indirect glycogen synthesis.

Amino acid transport was compared in human and in sheep erythrocytes. Kinetic studies established that human cells have three discrete amino acid transport systems, designated L, Ly + and ASC. The L system is partially stereospecific, with a preference for large neutral amino acids. L-leucine has a threefold lower apparent K m and a twofold smaller V max than D-leucine. Alanine, cysteine and possibly dibasic amino acids are transported by this route, but with a low affinity. The Ly + system is highly stereoselective, and specific for dibasic amino acids, including arginine. The ASC system is Na-dependent and selective for neutral amino acids of intermediate size. It has a particularly low apparent K m for cysteine and is stereospecific. Sheep erythrocytes lack these systems. Instead they possess an additional system (C system) responsible for the transport both of neutral and of dibasic amino acids, with cysteine as the optimal substrate. Although the substrate specificities of the human ASC and sheep C systems are similar, the sheep system does not require Na and has considerably higher apparent K m values. Dibasic amino acid transport (of lysine, but not of arginine) by the C system occurs with a low affinity.

The properties of Na+-dependent L-alanine transport in human erythrocytes were investigated using K+ as the Na+ substitute. Initial rates of Na+-dependent L-alanine uptake (0.2 mM extracellular amino acid) for erythrocytes from 22 donors ranged from 40 to 180 mumol/litre of cells per h at 37 degrees C. Amino acid uptake over the concentration range 0.1-8 mM was consistent with a single saturable component of Na+-dependent L-alanine transport. Apparent Km and Vmax. values at 37 and 5 degrees C measured in erythrocytes from the same donor were 0.27 and 0.085 mM respectively, and 270 and 8.5 mumol/litre of cells per h respectively. The transporter responsible for this uptake was identified as system ASC on the basis of cross-inhibition studies with a series of 42 amino acids and amino acid analogues. Apparent Ki values for glycine, L-alpha-amino-n-butyrate, L-serine and L-leucine as inhibitors of Na+-dependent L-alanine uptake at 37 degrees C were 4.2, 0.12, 0.16 and 0.70 mM respectively. Reticulocytes from a patient with inherited pyruvate kinase deficiency were found to have a 10-fold elevated activity of Na+-dependent L-alanine uptake compared with erythrocytes from normal donors. Separation of erythrocytes according to cell density (cell age) established that even the oldest mature erythrocytes retained significant Na+-dependent L-alanine transport activity. Amino acid transport was, however, a more sensitive indicator of cell age than acetylcholinesterase activity. Erythrocytes were found to accumulate L-alanine against its concentration gradient (distribution ratio approx. 1.5 after 4 h incubation), an effect that was abolished in Na+-free media. Na+-dependent L-alanine uptake was shown to be associated with L-alanine-dependent Na+ influx, the measured coupling ratio being 1:1.

Halopentacarbonylmetallates of Group VI react with ligands, L, in the presence of a Lewis acid to give LM(CO)5 (M = Cr, Mo, W) in high yield under mild conditions.

The dissipation of heat in the electrodes of multiaperture ion sources is a major factor in limiting the power output and beam pulse duration. The results of a series of tests on multiaperture and single aperture arrays are used as the basis for the derivation of formulas which define the limits of the practical operating regime for a single edge cooled electrode element.

Calculations of state functions in equilibrium plasmas produced behind shock-waves in potassium and caesium vapour are described and the results are presented graphically. For a given initial temperature T1 of the saturated vapour and a given Mach number M of the incident shock, the temperature, density and degree of ionization behind both the incident and reflected shocks were calculated from the Rankine Hugoniot relations and the Saha equation over the range 3

A large series of N-arylanthranilic acids has been prepared. Many of these compounds show high anti-inflammatory activity as measured by the anti-UV-erythema test. From this series have come the clinically useful non-steroidal anti-inflammatory agents, flufenamic acid (Arlef), mefenamic acid (Ponstel), and the latest and most potent agent, N-(2,6-dichloro-m-tolyl)anthranilic acid (meclofenamic acid, Meclomen = the sodium salt). The structure-activity relationships of this series is discussed and a graphical representation is presented which allows the prediction of activity of new agents.

ADEQUATE membrane transport of L-cysteine is necessary for red blood cell (RBC) survival, as this amino acid is essential for glutathione (GSH) synthesis and thus cell protection against oxidative damage. Thus, in sheep a genetically controlled L-cysteine transport defect leads to a reduced intracellular GSH concentration and shortened cell lifespan1–4. Human RBCs do not have the same amino acid transport system as sheep red blood cells (SRBC)5, the principal component being a high capacity, medium affinity system with a specificity broadly directed towards large neutral amino acids, the L-system of Christensen6. L-cysteine and its analogue L-α-amino-n-buty-rate are carried by the L-system in human RBCs, but with a low affinity7. Most experiments on amino acid transport in RBCs, particularly involving the L-system, have revealed substrate affinities with apparent Km values in the millimolar range, much higher than the physiological plasma levels of most amino acids. We have now investigated L-cysteine uptake in human RBCs over the concentration range 1–50 µm, as human plasma levels are around 20 µM8,9. As the early work of Yunis and Arimura10 has shown that glycine and L-alanine transport are partially Na-dependent, we have also investigated the effects of removing external Na on L-cysteine transport. We report here that human RBCs transport L-cysteine by a previously unidentified high affinity, low capacity, Na-dependent uptake mechanism. This system has a uniquely high affinity for its substrate and is the first Na-dependent transport mechanism to be kinetically characterised in mammalian erythrocytes. At physiological substrate concentrations it accounts for approximately half of the L-cysteine uptake into the cell.

JET tokamak performance has been progressively raised, culminating in operation at the full design level of 5 MA plasma current in a toroidal field at 3.4 T. the plasma current, position, shape and line-average electron density are controlled by feed-back systems. By glow discharge cleaning in H 2/methane mixtures, the interior of the vessel has been coated with carbon. This reduces the fraction of power radiated

Threonine uptake by the parasitic protozoan Trypanosoma brucei has been assessed using an oil-phase separation technique for measuring rapid amino acid fluxes. It was shown that the storage conditions for the organism were critical for the production of reproducible data. Using this method it has been shown that threonine uptake occurs rapidly, being linear for less than 30 s at 37 degrees C in contrast with previous reported results. Kinetic analysis of threonine uptake at 25 degrees C and at physiological plasma threonine levels (20-700 microM) gave a Km of 250 microM and a Vmax of 8 nmol mg-1 cell protein min-1. At these concentrations threonine uptake takes place against a concentration gradient.

Acetylchlorid (I) reagiert mit der Chromverbindung (II) bei Raumtemperatur unter Lichtausschlus zum Komplex (IIIa), der mit Stickstoffwasserstoffsaure zum Azido-carben-Komplex (IIIb) fuhrt.

Summary. This study examines the relationship between cognitive test scores, psychological symptoms and academic outcome for undergraduate chemistry students at University College, London, between the years 1956–61. There was some association between a high level of academic success, stress, and a high score of Valentine's reasoning test. Low cognitive test scores and psychological disturbance, however, did not relate to wastage and failure in this group of students.

Basic fibroblast growth factor (FGF-2) appeared to be ADP-ribosylated on the surface of adult bovine aortic arch endothelial and human hepatoma cells. Further characterization of this reaction with cells expressing an arginine-specific, glycosylphosphatidylinositol-anchored, mono-ADP-ribosyltransferase demonstrated that FGF-2 is ADP-ribosylated on arginine. Incubation of transformed cells with FGF-2 and [adenylate-32P]nicotinamide-adenine dinucleotide (NAD) resulted in the rapid incorporation of [32P]ADP-ribose into FGF-2 in a time-and concentration-dependent manner, with labelling averaging 3 mol of ADP-ribose/mol of FGF-2. Excess ADP-ribose had no effect on these reactions, whereas excess NAD inhibited the ADP-ribosylation of FGF-2, consistent with an enzymic rather than a non-enzymic ADP-ribosylation reaction. Heparin also inhibited the ADP-ribosylation reaction, whereas a neutralizing polyclonal anti-peptide antibody had no effect. Furthermore, the addition of putative receptor binding domain peptide analogues of FGF-2 reduced the maximal ADP-ribosylation of FGF-2. These results identify the cell-surface ADP-ribosylation of FGF-2 as a potentially ubiquitous event.

The new class of compounds R·C(X)·OAc [R = 2-furyl of CH2SiMe3; X = Cr(CO)5] react with HN3 to give nitriles and isonitriles.

A series of complexes LM(CO)5[M = Cr, Mo, or W; L = Me2PCH2CH2PMe2(dmpe), Ph2PCH2PPh2(dpm), Ph2PCH2CH2PPh2(dpe), Ph2PCH2CH2CH2PPh2(dpp), or Ph2PCH2CH2AsPh2(ape)] has been prepared and characterised by analysis, and i.r., mass, and n.m.r. spectroscopy. The complexes can be methylated with Me3OBF4 to give [(MeL)M(CO)5]BF4. The acid-assisted nucleophilic substitution reaction used in the formation of the complexs can also be applied to their conversion into bridged complexes, L[M(CO)5]2. Variations in geminal complexes coupling constants 2JPCH and aromatic solvent induced shifts for the series of complexes(dmpe)M(CO)n(M = Cr, Mo, or W; n= 4 or 5) are discussed and compared with those in (Me2PXCH2)2(X = O or S) and [(Me3PCH2)2](BF4)2, whose syntheses are also reported. Changes in the 31P chemical shift are used to demonstrate that the chelation shift is comparable to the co-ordination shift. Kinetic studies of the rate of the chelation reaction, LM(CO)5→ LM(CO)4+ CO, have been used to elucidate details of its mechanism. The reaction follows first-order kinetics, as required for the intramolecular process. The magnitude of the enthalpy of activation (ca. 140 kJ mol–1) and the similarity in rate between phosphorus and arsenic nucleophiles, suggest a large dissociative component in the activation. The positive entropy of activation and particularly its large variation (+6 to +71 J K–1 mol–1) suggest a concerted process in the transition state. The smaller the potential chelate ring, the faster the reaction in the series L = Ph2P(CH2)nPPh2(n= 1, 2 or 3); this appears to be largely an entropy effect.

The preparation of a series of isonitrile complexes, [(CO)6 –xM(CNR)x](x= 1–3; M = Cr, Mo; R = Me, Et, Pri, C6H11, But, p-tolyl, Ph, p-ClC6H4) is reported. The results of spectroscopic (i.r., u.v., mass, and n.m.r.— particularly aromatic solvent induced shifts) and electrochemical measurements are employed to assess the nature of the bonding in these systems. It is shown that the contribution of (d→π*)π-bonding is negligible and that variations in the donor strength of the isonitrile ligand are principally responsible for the changes observed. The compounds (RNC)Cr(CO)5 do not react with weak nucleophiles (amines, alcohols). Ketimine formation does not result from the reaction between (RNC)Cr(CO)5 and a silane in the presence of pyridine. The reaction between (RNC)2Cr(CO)4 and (Me2PCH2)2(dmpe) affords cis-(RNC)2(dmpe)Cr(CO)2 as the principal product, together with (dmpe)2Cr(CO)3.

The effect of changes in the electronic environment of the sp2 hybridised carbene carbon atom bound to the metal in a series of 18 complexes of the type (CO)5MCXY, where M = Cr or W; X = OR or NR1R2, and Y is an organic group, are discussed with the aid of 13C n.m.r. spectroscopy. The chemical shift of the carbene carbon is more strongly influenced by X than by either M or Y. Carbene complexes of the transition metals are better considered as metal-stabilised carbonium ions than as carbonyl (ester or amide) analogues. The resonances of the carbonyl ligands in carbene complexes are compared with those in isonitrile complexes of the type RNCCr(CO)5. Evidence is presented from both 13C and 1H n.m.r. spectra which shows that overall electron release rather than π→p interaction is important in the stabilisation of the carbene carbon by the group Y.