A novel measurement of Bs0B^0_s and Ds−D^-_s lifetimes using semileptonic decays at LHCb

I report new, world-leading LHCb results on heavy meson lifetimes. We use a novel approach that suppresses the shortcomings typically associated with reconstruction of semileptonic decays, allowing for precise measurements of lifetimes and other properties in collider experiments. We achieve a 15% and a $2\times$ improvement over current best determinations of the flavor-specific $B^0_s$ lifetime and $D^-_s$ lifetime, respectively.Comment: 12 pages, 6 figures. Talk presented at the APS Division of Particles and Fields Meeting (DPF 2017), July 31-August 4, 2017, Fermilab. C17073

IsRNA: An Iterative Simulated Reference State Approach to Modeling Correlated Interactions in RNA Folding

Coarse-grained RNA folding models promise great potential for RNA structure prediction. A key component in a coarse-grained folding model is the force field. One of the challenges in the coarse-grained force field calculation is how to treat the correlation between the different degrees of freedoms. Here, we describe a new approach (IsRNA) to extract the correlated energy functions from the known structures. Through iterative molecular dynamics simulations, we build the correlation effects into the reference states, from which we extract the energy functions. The validity of IsRNA is supported by the close agreement between the simulated Boltzmann-like probability distributions for all the structure parameters and those observed from the experimentally determined structures. The correlated energy functions derived here may provide a new tool for RNA 3D structure prediction

N₂O Formation Pathways over Zeolite-Supported Cu and Fe Catalysts in NH₃‑SCR

N₂O is a common byproduct in the NH₃-SCR reaction. We analyzed the N₂O formation pathways in NH₃-SCR over various catalysts (Cu-ZSM-5, Fe-ZSM-5, Cu-SAPO-34, Fe-SAPO-34, Cu-SSZ-13, and Fe-SSZ-13), aided by catalyst characterization using XRD, XPS, EDS mapping, and NH₃-TPD. The results showed that the NH₃ nonselective catalytic reduction was the major N₂O formation pathway for most of the Cu catalysts. The N₂O formation at lower temperatures (<300 °C) originated mainly from decomposition of NH₄NO₃. In addition, NH₃ nonselective oxidation was another reaction that formed N₂O especially at higher temperatures. The N₂O resulting from the Eley–Rideal mechanism was also favored at higher temperatures. The decomposition of NO to N₂O and O₂ also led to N₂O formation, although its contribution was minimal. The absence of N₂O yield over most Fe catalysts could be attributed to active N₂O decomposition and N₂O-SCR reactions. Moreover, varying O₂ and H₂O concentrations in the feed exerted strong influence on both N₂O formation and SCR activity. Decrease in O₂ level from 14% to 3% led to continual decline in N₂O formation but had no effect on SCR activity until reaching a threshold concentration of 2%. H₂O in lower concentrations (2–3%) facilitated N₂O formation and NO conversion due to increase in Brønsted acidity, while H₂O in higher concentrations (>5%) led to suppression of these reactions due to the coverage of active sites

Prediction of the <i>Lw-</i>IAG signal peptide in <i>Lysmata wurdemanni</i>.

<p>The <i>Lw</i>-IAG protein belongs to hydrophobic protein, which consists of s a signal peptide, B chain, C peptide and A chain, and six conserved Cys residues. The <i>Lw</i>-IAG protein contains one O-glycosylation site, five phosphorylation sites and one N-glycosylation site. The cleavage site of the signal peptidase is between the 27^th and 28^th amino acids.</p

Copper-Catalyzed Cascade Transformation of <i>O</i>‑Propargylic Oximes with Sulfonyl Azides to α,β-Unsaturated <i>N</i>‑Acylamidines

Copper-catalyzed cascade transformations of <i>O-</i>propargylic oximes and sulfonyl azides were carried out to efficiently afford α,β-unsaturated <i>N</i>-acylamidines. The reaction involved the intramolecular attack of the oxime group to the ketenimine moiety that was generated in situ, followed by the cleavage of the N–O bond

Immunofluorescence localization of <i>Lw</i>-IAG in <i>Lysmata wurdemanni</i>.

<p>Immunofluorescence was performed on sections of the androgenic gland from male-phase (A–C) and euhermaphrodite-phase shrimp (D–F). Specific signal (red) appears only in the AG cells of the male-phase shrimp. Nuclei (blue) were stained with DAPI, circles represent the area of AG cells. The white lines represent the boundary of posterior vas deferens (PVD). m: muscle layer of PVD. C: merged image of A and B; the enlarged view of AG cells is inset. The <i>Lw</i>-IAG was only expressed in cytoplasm based on the merged picture of the male-phase shrimp. F: merged image of D and E. Bar = 50 μm.</p

Multiple sequence alignment of deduced primary amino acid sequences of decapod <i>IAGs</i> using Clustal W.

<p><i>Cherax quadricarinatus</i>: ABH07705.1; <i>Cherax destructor</i>: ACD91988.1; <i>Macrobrachium rosenbergii</i>: ACJ38227.1; <i>Portunus pelagicus</i>: HM459854.1; <i>Penaeus monodon</i>: ADA67878.1; <i>Marsupenaeus japonicus</i>: BAK20460.1 <i>Macrobrachium lar</i>: BAJ78349.1; <i>Macrobrachium nipponense</i>: AGB56976.1. The amino acid sequence of <i>Lw-LAG</i> is indicated by an arrow. The boundary between signal peptide and B chain is represented by a dotted vertical line. Conserved amino acids are indicated in different colors. B and A chains are marked with dotted and sold lines, respectively. The asterisk indicates the positions of conserved Cys residues in all species.</p

Amplified CDS of the <i>Lw-IAG</i> gene in <i>Lysmata wurdemanni</i>.

<p>RT-PCR shows the <i>Lw-IAG</i> gene’s CDS area. ACTB served as a loading control of total cDNA, and water without cDNA was employed as a negative control. A single band of 254bp was observed in ACTB sample. Bands at 528bp were observed in <i>Lw-IAG</i> samples but not in the water sample.</p

Expression of the <i>IAG</i> gene in <i>Lysmata wurdemann</i> in different phases.

<p>MP: male phase, E: euhermaphrodite phase. Relative expression levels of the <i>IAG</i> gene (2^{-ΔΔ<i>CT</i>}) were quantified in male- and euhermaphrodite-phase shrimp by real-time PCR. Asterisks represent highly significant difference between two phases (Student’s <i>t</i>-test, n = 9, <i>P</i> < 0.01).</p

Entropic Interactions in Semiflexible Polymer Nanocomposite Melts

By employing molecular dynamics simulations, we explored the effective depletion zone for nanoparticles (NP) immersed in semiflexible polymer melts and calculated the entropic depletion interactions between a pair of NPs in semiflexible polymer nanocomposite melts. The average depletion zone volumes rely mainly on polymer chain stiffness and increase with chain stiffness increasing. In the semiflexible polymer nanocomposite melts, the entropic depletion interactions are attractive and anisotropic, and increase with chain stiffness increasing. Meanwhile, the attractive interactions between NPs and polymers can also affect strongly the entropic depletion interactions. For the semiflexible polymer nanocomposite melts in the athermal system, the entropic depletion interactions change from anisotropic to isotropic when the NP/polymer interactions increase. For NPs in the rodlike polymer melts, a mixture structure of contact/“bridging” aggregations for NPs is formed at a strong attractive NP/polymer interaction. Our calculations can provide an effective framework to predict the morphology of NPs immersed in semiflexible polymer melts