Nitric Oxide Adsorption and Reduction Reaction Mechanism on the Rh₇⁺ Cluster: A Density Functional Theory Study

The transition metal rhodium has been proved the effective catalyst to convert from NOx to N2. In the present work, we are mainly focused on the NO adsorption and decomposition reaction mechanism on the surface of the Rh7+ cluster, and the calculated results suggest that the reaction can proceed via three steps. First, the NO can adsorb on the surface of the Rh7+ cluster; second, the NO decomposes to N and O atoms; finally, the N atom reacts with the second adsorbed NO and reduces to a N2 molecule. The N–O bond breaks to yield N and O atoms in the second step, which is the rate-limiting step of the whole catalytic cycle. This step goes over a relatively high barrier (TS12) of 39.6 kcal/mol and is strongly driven by a large exothermicity of 55.1 kcal/mol during the formation of stable compound 3, accompanied by the N and O atoms dispersed on the different Rh atoms of the Rh7+ cluster. In addition, the last step is very complex due to the different possibilities of reaction mechanism. On the basis of the calculations, in contrast to the reaction path II that generates N2 from two nitrogen atoms coupling, the reaction path I for the formation of intermediate N2O is found to be energetically more favorable. Present work would provide some valuable fundamental insights into the behavior of the nitric oxide adsorption and reduction reaction mechanism on the Rh7+ cluster

Does Fish Oil Have an Anti-Obesity Effect in Overweight/Obese Adults? A Meta-Analysis of Randomized Controlled Trials

<div><p>Context</p><p>Accumulating evidence has suggested favorable effects of fish oil on weight loss in animal experiments; however, findings remain inconsistent in humans.</p><p>Objects</p><p>The meta-analysis was performed to investigate the influence of fish oil on some parameters of body composition in overweight/obese adults.</p><p>Design</p><p>Human randomized, placebo-controlled trials were identified by a systematic search of Embase, PubMed, the Cochrane Library, web of science and reference lists of related reviews and articles. The random-effects model was used to estimate the calculated results.</p><p>Results</p><p>In total, 21 studies with 30 study arms were included in this analysis. Calculated results of the meta-analysis demonstrated that fish oil had no effect on reducing body weight (overall SMD = -0.07, 95% CI -0.21 to 0.07, <i>P</i> = 0.31) and BMI (overall SMD = -0.09, 95% CI -0.22 to 0.03, <i>P</i> = 0.14) whether alone or combined with life modification intervention in overweight/obese subjects. However, waist circumference was significantly reduced (SMD = -0.23, 95% CI -0.40 to -0.06, <i>P</i> = 0.008) in those with fish oil supplementation combined with life modification intervention. Waist hip ratio (WHR) was significantly reduced (overall SMD = -0.52 95% CI -0.76 to -0.27, <i>P</i> < 0.0005) in fish oil supplemented individuals with or without combination life modification intervention.</p><p>Conclusion</p><p>Current evidence cannot support an exact anti-obesity role of n-3 polyunsaturated fatty acids (PUFAs) in overweight/obese subjects. However, these subjects may benefit from reducing abdominal fat with fish oil supplementation especially when combined with life modification intervention. Further large-scale and long-term clinical trials are needed to gain definite conclusions.</p></div

Density and Viscosity of Ternary Mixture of Cyclopentanol + <i>exo</i>-Tetrahydrodicyclopentadiene + 1,3-Dimethyladamantane

Oxygenated additives have been proved to improve the property of an aviation fuel, such as reducing pernicious emissions and adjusting physical properties, and an appropriate alcohol is usually a typical candidate. To understand the properties of high-energy-density hydrocarbon fuels with alcohol, densities (ρ) and viscosities (η) of ternary system, cyclopentanol + exo-tetrahydrodicyclopentadiene (JP-10) + 1,3-dimethyladamantane (1,3-DMA), and their corresponding binary systems, have been determined over the whole composition range at different temperatures, T = (293.15–333.15) K, and atmospheric pressure, p = 0.1 MPa. The excess molar volumes (VmE) and the viscosity deviations (Δη) of the binary systems mixtures were calculated and fitted to the Redlich–Kister equation, while those of the ternary systems were calculated and fitted to four different semiempirical equations. The results show that the addition of cyclopentanol can lead to a little higher density and a lower viscosity, which are beneficial to the design and performance of hydrocarbon fuels

Forest plots from meta-analyses for the effects of fish oil on changes in body weight (A), BMI (B), waist circumference (C), and WHR (D).

<p>Forest plots from meta-analyses for the effects of fish oil on changes in body weight (A), BMI (B), waist circumference (C), and WHR (D).</p

Funnel plots from meta-analyses for the effects of fish oil on changes in body weight (A) and BMI (B).

<p>Funnel plots from meta-analyses for the effects of fish oil on changes in body weight (A) and BMI (B).</p

Explore the Catalytic Reaction Mechanism in the Reduction of NO by CO on the Rh₇⁺ Cluster: A Quantum Chemical Study

Rhodium has been proved to possess unique reactivity to convert NO_<i>x</i> into N₂ with high conversion efficiency and selectivity. In this study, we have carried out DFT calculations on the reaction mechanism in the reduction of NO by CO on the surface of the Rh₇⁺ cluster. The calculated results suggest that the reaction proceeds via three steps. First, the NO and CO are adsorbed on the Rh₇⁺ cluster, then the adsorbed NO decomposes to N and O atoms. The O atom reacts with the adsorbed CO leading to the formation of CO₂ molecule. Second, another NO is adsorbed on the rhodium cluster and decomposes to N and O atoms, then the two N atoms couple with each other to yield N₂ molecule. Finally, the second CO can be adsorbed on the Rh₁ or Rh₇ atom of the Rh₇⁺ cluster and oxidized to CO₂ molecule. On the basis of present calculations from gas-phase Gibbs free energy profiles, the reaction path related to CO adsorption on the Rh₇ atom is energetically more favorable. The second adsorbed NO generating N and O atoms in the second step is the rate-limiting step of whole catalytic cycle. The high activation barrier (TS₆₇) of 56.6 kcal/mol can be driven by large exergonic reaction. Our work would provide some valuable fundamental insights into the reaction mechanism between NO and CO on the rhodium surface, which is vitally important to decrease NO emissions in automotive exhaust gas

Subgroup estimation of the effects of fish oil on BMI changes.

<p>Subgroup estimation of the effects of fish oil on BMI changes.</p

Subgroup estimation of the effects of fish oil on body weight changes.

<p>Subgroup estimation of the effects of fish oil on body weight changes.</p

PRISMA 2009 flow diagram illustrates the study selection procedure.

<p><i>From</i>: Moher D, Liberati A, Tetzlaff J, Altman DG, The PRISMA Group (2009). <i>P</i>referred <i>R</i>eporting <i>I</i>tems for <i>S</i>ystematic Reviews and <i>M</i>eta-<i>A</i>nalyses: The PRISMA Statement. PLoS Med 6(6): e1000097. doi:10.1371/journal.pmed1000097. <b>For more information, visit</b><a href="http://www.prisma-statement.org" target="_blank">www.prisma-statement.org</a>.</p