Geometrical Effects on Sintering Dynamics of Cu–Ag Core–Shell Nanoparticles

Understanding of the nanoparticle (NP) sintering mechanism at the atomic scale is of significance for improving various NP applications, such as printable nanoinks, catalysts, and electrode materials in energy devices. In this research, sintering dynamics of Cu–Ag core–shell NPs with various geometries are investigated through molecular dynamics simulations under different temperatures. The evolutions of local crystalline structure, characterized by common neighbor analysis, and potential energy during the sintering are studied to identify the sintering mechanisms. Sintering of two equally sized NPs is divided into three stages according to the shrinkage evolution, and depending on the sintering stage and condition, NP undergoes reorientation for achieving epitaxial layering, plastic deformation, surface diffusion, wetting, and crystallization–amorphization–recrystallization. Although the Cu core is coalescent neither in solid phase nor in surface-premelting-induced sintering, it can enhance the mobility of Ag shell atoms. The size-dependent optimal core radius/shell thickness ratio is proposed to achieve maximum densification and thus maximum bonding strength at room temperature

Oxidative Cleavage of the β‑O‑4 Linkage of Lignin by Transition Metals: Catalytic Properties and the Performance of Density Functionals

The catalytic degradation of lignin is of considerable interest because the depolymerization of lignin to small molecules is the initial step for the conversion of lignin to biofuels and other useful chemicals. Because of the complex structure of lignin, methoxyethane was used in this study as a representative model of the most common linkage within lignin, the β-O-4 linkage. The completely renormalized coupled cluster with singles, doubles, and perturbative triples [CR-CCSD­(T)] method was used to calculate the energetics of the C–O bond cleavage in methoxyethane by late 3d, 4d, and 5d transition metal atoms and to evaluate the performance of a set of density functionals (BLYP, B97D, TPSS, M06L, B3LYP, PBE0, M06, TPSSh, and B2PLYP) in predicting the reaction energetics

Environmentally Friendly Strategy for Treating In Situ Leaching Solutions of Ion-Adsorption Type Yttrium-Rich Heavy Rare-Earth Ore by a Bubble-Supported Organic Liquid Membrane

A novel environmentally friendly strategy based upon bubble-supported organic liquid membrane (BSOLM) extraction using saponified naphthenic acid as extractant is proposed in the present work for treating the in situ leaching solutions of ion-adsorption type yttrium-rich heavy rare-earth ores in South China. It was revealed that selectively preferential separation of non-yttrium rare earths from yttrium can be achieved, while the electrolyte aluminum salt can be retained in the raffinates for subsequent return as the leaching reagent for performing in situ leaching of ion-adsorption type heavy rare-earth ores. The BSOLM extraction exhibits an obvious advantage over conventional extraction in promoting the competitive mass transfer and separation of coexisting rare earths from yttrium and other non-rare-earth impurity ions. Using erbium as a representative of heavy rare earths, it was found that the differences in diffusive mass transfer rate of Er3+, Y3+, and Al3+ ions in the boundary layer of laminar flow near the surface of the extractant liquid membrane result in their enhanced separation. The BSOLM extraction prevents the convective disturbance along the normal vertical direction of the interface due to the irregular movement of dispersed oil droplets in the conventional extraction and therefore inhibit the co-extraction of Al3+ ions. The effects of Al3+ ion concentrations in aqueous feed solutions, initial aqueous pHs, concentrations of naphthenic acid, and its saponification degree on the separation efficiency were investigated. Experimental results confirmed that competitive hydration and adsorption of Al3+ ions at the interface play an important role in increasing the difference in concentration distribution of Er3+ and Y3+ ions near the interface during BSOLM extraction; therefore, the separation of rare earths from yttrium can be controllable

Effect of various storage conditions on the stability of quinolones in raw milk

<p>Research on the storage stability of antibiotic residues in milk is important for method development or validation, milk quality control and risk assessment during screening, confirmation, qualitative or quantitative analysis. This study was conducted using UPLC-MS/MS to determine the stability of six quinolones – ciprofloxacin (CIP), danofloxacin (DAN), enrofloxacin (ENR), sarafloxacin (SAR), difloxacin (DIF) and flumequine (FLU) – in raw milk stored under various conditions to investigate if quinolones degrade during storage of milk, and finally to determine optimal storage conditions for analysis and scientific risk assessment of quinolone residues in raw milk. The storage conditions included different temperatures and durations (4°C for 4, 8, 24 and 48 h; –20°C for 1, 7 and 30 days; –80°C for 1, 7 and 30 days), thawing temperatures (25, 40 and 60°C), freeze–thaw cycles (1–5), and the addition of different preservatives (sodium thiocyanate, sodium azide, potassium dichromate, bronopol and methanal). Most quinolones exhibited high stability at 4°C for up to 24 h, but began to degrade after 48 h. In addition, no degradation of quinolones was seen when milk samples were stored at –20°C for up to 7 days; however, 30 days of storage at –20°C resulted in a small amount of degradation (about 30%). Similar results were seen when samples were stored at –80°C. Moreover, no losses were observed when frozen milk samples were thawed at 25, 40 or 60°C. All the quinolones of interest, except sarafloxacin, were stable when milk samples were thawed at 40°C once and three times, but unstable after five freeze–thaw cycles. Preservatives affected the stability of quinolones, but the effects differed depending on the preservative and quinolone. The results of this study indicate optimum storage protocols for milk samples, so that residue levels reflect those at the time of initial sample analysis, and should improve surveillance programmes for quinolones in raw milk.</p

Transcriptome difference and potential crosstalk between liver and mammary tissue in mid-lactation primiparous dairy cows

<div><p>Liver and mammary gland are among the most important organs during lactation in dairy cows. With the purpose of understanding both the different and the complementary roles and the crosstalk of those two organs during lactation, a transcriptome analysis was performed on liver and mammary tissues of 10 primiparous dairy cows in mid-lactation. The analysis was performed using a 4×44K Bovine Agilent microarray chip. The transcriptome difference between the two tissues was analyzed using SAS JMP Genomics using ANOVA with a false discovery rate correction (FDR). The analysis uncovered >9,000 genes differentially expressed (DEG) between the two tissues with a FDR<0.001. The functional analysis of the DEG uncovered a larger metabolic (especially related to lipid) and inflammatory response capacity in liver compared with mammary tissue while the mammary tissue had a larger protein synthesis and secretion, proliferation/differentiation, signaling, and innate immune system capacity compared with the liver. A plethora of endogenous compounds, cytokines, and transcription factors were estimated to control the DEG between the two tissues. Compared with mammary tissue, the liver transcriptome appeared to be under control of a large array of ligand-dependent nuclear receptors and, among endogenous chemical, fatty acids and bacteria-derived compounds. Compared with liver, the transcriptome of the mammary tissue was potentially under control of a large number of growth factors and miRNA. The <i>in silico</i> crosstalk analysis between the two tissues revealed an overall large communication with a reciprocal control of lipid metabolism, innate immune system adaptation, and proliferation/differentiation. In summary the transcriptome analysis confirmed prior known differences between liver and mammary tissue, especially considering the indication of a larger metabolic activity in liver compared with the mammary tissue and the larger protein synthesis, communication, and proliferative capacity in mammary tissue compared with the liver. Relatively novel is the indication by the data that the transcriptome of the liver is highly regulated by dietary and bacteria-related compounds while the mammary transcriptome is more under control of hormones, growth factors, and miRNA. A large crosstalk between the two tissues with a reciprocal control of metabolism and innate immune-adaptation was indicated by the network analysis that allowed uncovering previously unknown crosstalk between liver and mammary tissue for several signaling molecules.</p></div

The information of real time PCR primers of target genes detected in mammary epithelial cell from dairy cattle <i>by in vitro</i> culture with different arginine levels.

<p>The information of real time PCR primers of target genes detected in mammary epithelial cell from dairy cattle <i>by in vitro</i> culture with different arginine levels.</p

Milk concentration in nine infected lactating cows' quarters with high (<i>n</i> = 10), mid (<i>n</i> = 10) and low (<i>n</i> = 11) production after eight infusions of ceftiofur hydrochloride at 24-h intervals, 125 mg/quarter, into all four quarters, plotted with MIC ₉₀ (0.25 μg/mL).

<p>Milk concentration in nine infected lactating cows' quarters with high (<i>n</i> = 10), mid (<i>n</i> = 10) and low (<i>n</i> = 11) production after eight infusions of ceftiofur hydrochloride at 24-h intervals, 125 mg/quarter, into all four quarters, plotted with MIC ₉₀ (0.25 μg/mL).</p

Cubic regression analysis of signaling parthway related gene expression and arginine concentration.

<p>Panel A, JAK2; Panel B, STAT5; Panel C, mTOR; Panel D, S6K; and Panel E, 4EBP1.</p

Immunofluorescence of Cytokeratin 18 (CK-18) (×200).

<p>Immunofluorescence of Cytokeratin 18 (CK-18) (×200).</p

Mean-serum concentration (±SD) in healthy (<i>n</i> = 3) and infected (<i>n</i> = 3) cows administered eight intramammary infusions of ceftiofur hydrochloride at a dose of 125 mg/quarter each 24 h.

<p>Arrows indicate time of daily infusion of ceftiofur into all four quarters.</p