Parametric inference for discrete observations of diffusion processes with mixed effects

Stochastic differential equations with mixed effects provide means to model intra-individual and inter-individual variability in repeated experiments leading to longitudinal data. We consider N i.i.d. stochastic processes defined by a stochastic differential equation with linear mixed effects which are discretely observed. We study a parametric framework with distributions leading to explicit approximate likelihood functions and investigate the asymptotic behavior of estimators under the asymptotic framework : the number N of individuals (trajectories) and the number n of observations per individual tend to infinity within a fixed time interval. The estimation method is assessed on simulated data for various models.     

A note on relatives to the Held and Karp 1-tree problem

We study a class of graph problems which includes as special cases the Held and Karp 1-tree problem, and the minimum spanning tree problem with one degree constraint studied by Glover and Klingman. For another special case, we note a mistake in a paper by Ramesh, Yoon and Karwan.     

A stabilized column generation scheme for the traveling salesman subtour problem

Given an undirected graph with edge costs and both revenues and weights on the vertices, the traveling salesman subtour problem is to find a subtour that includes a depot vertex, satisfies a knapsack constraint on the vertex weights, and that minimizes edge costs minus vertex revenues along the subtour.We propose a decomposition scheme for this problem. It is inspired by the classic side-constrained 1-tree formulation of the traveling salesman problem, and uses stabilized column generation for the solution of the linear programming relaxation. Further, this decomposition procedure is combined with the addition of variable upper bound (VUB) constraints, which improves the linear programming bound. Furthermore, we present a heuristic procedure for finding feasible subtours from solutions to the column generation problems. An extensive experimental analysis of the behavior of the computational scheme is presented.     

Magnetisch nichtäquivalente Methylenprotonen in einigen 2-substituierten 1,3-Benzodioxanen

Zusammenfassung Die magnetische Nichtäquivalenz der Methylenprotonen in 2-R-Benzo-1,3-dioxanen, mit R=C₆H₅,o-ClC₆H₄,m-ClC₆H₄,p-ClC₆H₄,o-BrC₆H₄,m-BrC₆H₄,p-BrC₆H₄,o-NO₂C₆H₄,m-NO₂C₆H₄,p-NO₂C₆H₄,o-CH₃OC₆H₄,m-CH₃OC₆H₄,p-CH₃OC₆H₄, -Naphthyl, -Naphthyl, -Thienyl und -Thienyl, wurde in (CD₃)₂CO, CDCl₃, CCl₄, CS₂ und C₆D₆ untersucht.

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Magnetic non equivalent methylenic protons of some 2-substituted 1.3-benzodioxanes

The magnetic non equivalence of the methylenic protons in 2-R-1.3-benzodioxanes, with R=C₆H₅,o-ClC₆H₄,m-ClC₆H₄,p-ClC₆H₄,o-BrC₆H₄,m-BrC₆H₄,p-BrC₆H₄,o-NO₂C₆H₄,m-NO₂C₆H₄,p-NO₂C₆H₄,o-CH₃OC₆H₄,m-CH₃OC₆H₄,p-CH₃OC₆H₄, -naphthyl, -naphthyl, -thienyl and -thienyl were studied in (CD₃)₂CO, CDCl₃, CCl₄, CS₂ and C₆D₆.

     

Nanospray analysis of the venom of the tarantula Theraphosa leblondi: a powerful method for direct venom mass fingerprinting and toxin sequencing

Mass spectrometric methods, including matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOFMS), on-line liquid chromatography/electrospray ionisation mass spectrometry (LC/ESI-MS), and nanospray ionisation/hybrid quadrupole time-of-flight mass spectrometry (nanoESI-QqTOFMS), were applied to characterize by mass fingerprinting the venom of the French Guyanese tarantula Theraphosa leblondi. Of these techniques direct nanoESI-QqTOFMS, which allowed the detection of 65 protonated molecules with high mass accuracy, appeared to give the best results. Three major peptides, TlTx1, TlTx2 and TlTx3, were sequenced using a combination of nanoESI-MS/MS and enzyme digestion/MS and MS/MS experiments. Each sequence was confirmed by automated Edman sequencing. In patch-clamp experiments these peptides were found to have a specific inhibitory effect on the voltage-dependent potassium channel, Kv4.2.     

Surface‐Confined Self‐Assembled Janus Tectons: A Versatile Platform towards the Noncovalent Functionalization of Graphene

A general strategy for simultaneously generating surface‐based supramolecular architectures on flat sp²‐hybridized carbon supports and independently exposing on demand off‐plane functionality with controlled lateral order is highly desirable for the noncovalent functionalization of graphene. Here, we address this issue by providing a versatile molecular platform based on a library of new 3D Janus tectons that form surface‐confined supramolecular adlayers in which it is possible to simultaneously steer the 2D self‐assembly on flat C(sp²)‐based substrates and tailor the external interface above the substrate by exposure to a wide variety of small terminal chemical groups and functional moieties. This approach is validated throughout by scanning tunneling microscopy (STM) at the liquid–solid interface and molecular mechanics modeling studies. The successful self‐assembly on graphene, together with the possibility to transfer the graphene monolayer onto various substrates, should considerably extend the application of our functionalization strategy.     

Diastereotope Methylenprotonen und Methylgruppen in 2-Substituierten 1,6-Methano [10] Annulenen

The double magnetic non equivalence of the diastereotopic methylene protons resp. geminal methyl groups of 2-substituted 1,6-methano [10]annulenes were observed in five solvents. It was found that Δν_AB for one of the two methylene groups were much smaller than Δν_{A ‘B’} for the other and that Δν_A‘B’ was much more solvent dependent than Δν_AB. Δν_{A “B”} for the bridge protons varied very little with the solvent used.     

(Hetero)Arylation of 6‐Halogenoimidazo[1,2‐a]pyridines Differently Substituted at C(2): Influence of the 2‐Substituent on the Suzuki Cross‐Coupling Reaction

We previously reported that reactivity towards the Suzuki cross‐coupling reaction of 3‐iodoimidazo[1,2‐a]pyridines substituted at C(2) is largely influenced by the nature of this 2‐substituent. Hence, with the aim to expand the scope of this coupling process to the 6‐position of this series, it seemed important to similarly determine the influence of the nature of the 2‐substituent (H, alkyl, or aryl) on the rate of coupling. From this work, the Suzuki‐type cross‐coupling was shown to proceed efficiently on 6‐bromo‐2‐methyl‐ and 2‐(4‐fluorophenyl)imidazo[1,2‐a]pyridines, whereas the 6‐Br derivative unsubstituted at C(2) appeared to be poorly reactive. By modifying the reaction conditions in terms of catalyst and base, and the nature of the halogen, the reactivity of the unsubstituted series was largely enhanced. Finally, this work led us to establish efficient and convenient Suzuki reaction conditions for the 6‐(hetero)arylation of 6‐halogenoimidazo[1,2‐a]pyridines depending on the nature of the 2‐substituent and boronic acid.     

Trifluoromethyl radical triggered radical cyclization of N-benzoyl ynamides leading to isoindolinones

Science China Chemistry - Under photocatalytic reductive conditions, trifluoromethyl radical addition onto an ynamide followed by cyclization on a benzoyl moiety produces diverse isoindolinone...