Optical absorption of small copper clusters in neon: Cu-n, (n=1-9)

We present optical absorption spectra in the UV-visible range (1.6 eV omega < 5.5 eV) of mass selected neutral copper clusters Cu-n(n = 1-9) embedded in a solid neon matrix at 7 K. The atom and the dimer have already been measured in neon matrices, while the absorption spectra for sizes between Cu-3 and Cu-9 are entirely (n = 6-9) or in great part new. They show a higher complexity and a larger number of transitions distributed over the whole energy range compared to similar sizes of silver clusters. The experimental spectra are compared to the time dependent density functional theory (TD-DFT) implemented in the TURBOMOLE package. The analysis indicates that for energies larger than 3 eV the transitions are mainly issued from d-type states; however, the TD-DFT scheme does not reproduce well the detailed structure of the absorption spectra. Below 3 eV the agreement for transitions issued from s-type states is better. (C) 2011 American Institute of Physics. [doi:10.1063/1.3552077

Ultraviolet-visible absorption of small silver clusters in neon: Ag-n (n=1-9)

We present optical absorption and fluorescence spectra in the UV-visible range of size selected neutral Ag-n clusters (n = 1-9) in solid neon. Rich and detailed optical spectra are found with linewidths as small as 50 meV. These spectra are compared to time dependent density functional theory implemented in the TURBOMOLE package. Excellent agreement between theory and experiment is achieved in particular for the dominant spectroscopic features at photon energies below 4.5 eV. This allows a clear attribution of the observed electronic transitions to specific isomers. Optical transitions associated to the s-electrons are concentrated in the energy range between 3 and 4 eV and well separated from transitions of the d-electrons. This is in contrast to the other coinage metals (Au and Cu) which show a strong coupling of the d-electrons. (C) 2011 American Institute of Physics. [doi:10.1063/1.3589357

Glucose-fructose beverages do not alter the effects of training on lactate metabolism

Glucose-fructose beverages do not alter the effects of training on lactate metabolism Rosset R., Egli L., Cros J., Schneiter P. and Tappy L. and Lecoultre V. Department of Physiology, University of Lausanne, Lausanne, Switzerland. Introduction It is generally accepted that lactate is produced by skeletal muscle during exercise, and is either used in adjacent muscle fibers (lactate shuttle) or recycled to glucose in the liver. We have shown that ingestion of fructose-containing drinks stimulates lactate production and release from the liver during exercise, and that fructose-derived lactate is subsequently used as an energy substrate by muscle. The regulation of this liver to muscle fructose-lactate shuttle remains unknown. In this study, we assessed whether consumption of fructose-containing beverages alters the effects of training on fructose and lactate metabolism. Methods Two groups of eight sedentary male subjects were endurance-trained for three weeks while ingesting 489 mL/h of either a 9.8%-glucose 6.2%-fructose beverage (GLUFRU) or water (C) during exercise training sessions. An incremental test to exhaustion and a metabolic test were performed before and after the interventions to assess training adaptations and substrate use during endurance-type exercise. Indirect calorimetry, [1-13C]lactate and [6,6-2H2]glucose were used to calculate plasma lactate appearance, clearance and oxidation and glucose kinetics. Results Anthropometrics and performance parameters were similar in both groups at baseline. Plasma glucose concentrations (+1±3 vs. +3±3 % vs. baseline values), glucose rate of appearance (+3±7 vs. +2±3 %) and metabolic clearance (+6±8 vs. +1±5 %) remained stable after both GLUFRU and C training (all p=n.s.). Overall, lactate concentrations were decreased after intervention in both GLUFRU and C, but not differently between groups (-10±5 vs. -20±4 %; p&lt;0.01 vs. baseline, p=n.s. between GLUFRU and C), as a result of an increased lactate metabolic clearance (+26.5±11.4 vs. +17.5±10.2 mL·min-1; p=0.01 vs. baseline, p=0.56 between GLUFRU and C). Lactate appearance (+10±6 vs. -4±9 %) and oxidation (+9±6 vs. - 6±9 %) remained unchanged across time and conditions (all p=n.s.). Maximal oxygen consumption (+287±53 vs. +249±104 mL·min-1) and power eliciting lactate threshold (+25±5 vs. +25±8 W) were similarly increased in GLUFRU and C (both p&lt;0.01 vs. baseline, p=n.s. between GLUFRU and C). Discussion These data corroborate our earlier observation that fructose is converted into lactate by the liver and subsequently oxidized during exercise. Endurance training did not alter liver lactate release, but increased lactate metabolic clearance. The effects of endurance training were not differently altered by the consumption of fructose during training sessions, however

UV-visible absorption of small gold clusters in neon: Au-n (n=1-5 and 7-9)

We present optical absorption spectra in the UV-visible range (1.5 eV < E < 6 eV) for mass selected neutral gold clusters Au-n (n = 1-5 and 7-9) embedded in solid Ne at 7 K. The experimental spectra are compared with time-dependent density functional calculations. Electronic transitions are distributed over the whole energy range without any concentration of the oscillator strength in a small energy window, characteristic for the more s-like metals such as the alkalis or silver. Contrary to the case of silver and partly copper clusters, transitions issued from mainly d-type states are significantly involved in low energy transitions. The measured integrated cross section is smaller (<20%) than expected from a free-electron system, manifesting the strong screening of the s electrons due to the proximity of the s and d levels in gold. (C) 2011 American Institute of Physics. [doi:10.1063/1.3537739

Effects of Dietary Protein and Fat Content on Intrahepatocellular and Intramyocellular Lipids during a 6-Day Hypercaloric, High Sucrose Diet: A Randomized Controlled Trial in Normal Weight Healthy Subjects.

Sucrose overfeeding increases intrahepatocellular (IHCL) and intramyocellular (IMCL) lipid concentrations in healthy subjects. We hypothesized that these effects would be modulated by diet protein/fat content. Twelve healthy men and women were studied on two occasions in a randomized, cross-over trial. On each occasion, they received a 3-day 12% protein weight maintenance diet (WM) followed by a 6-day hypercaloric high sucrose diet (150% energy requirements). On one occasion the hypercaloric diet contained 5% protein and 25% fat (low protein-high fat, LP-HF), on the other occasion it contained 20% protein and 10% fat (high protein-low fat, HP-LF). IHCL and IMCL concentrations (magnetic resonance spectroscopy) and energy expenditure (indirect calorimetry) were measured after WM, and again after HP-LF/LP-HF. IHCL increased from 25.0 ± 3.6 after WM to 147.1 ± 26.9 mmol/kg wet weight (ww) after LP-HF and from 30.3 ± 7.7 to 57.8 ± 14.8 after HP-LF (two-way ANOVA with interaction: p &lt; 0.001 overfeeding x protein/fat content). IMCL increased from 7.1 ± 0.6 to 8.8 ± 0.7 mmol/kg ww after LP-HF and from 6.2 ± 0.6 to 6.9 ± 0.6 after HP-LF, (p &lt; 0.002). These results indicate that liver and muscle fat deposition is enhanced when sucrose overfeeding is associated with a low protein, high fat diet compared to a high protein, low fat diet

Combining loss of function of FOLYLPOLYGLUTAMATE SYNTHETASE1 and CAFFEOYL-COA 3-O-METHYLTRANSFERASE1 for lignin reduction and improved saccharification efficiency in Arabidopsis thaliana

This article tests if lignin content can be further reduced by combining genetic mutations in C1 metabolism and the lignin biosynthetic pathway by generating and functionally characterizing fpgs1ccoaomt1 double mutants. The observations demonstrate that additional reduction in lignin content and improved sugar release can be achieved by simultaneous downregulation of a gene in the C1 (FPGS1) and lignin biosynthetic (CCOAOMT) pathways