Structural network inference from time-series data using a generative model and transfer entropy

In this paper we develop a novel framework for inferring a generative model of network structure representing the causal relations between data for a set of objects characterized in terms of time series. To do this we make use of transfer entropy as a means of inferring directed information transfer between the time-series data. Transfer entropy allows us to infer directed edges representing the causal relations between pairs of time series, and has thus been used to infer directed graph representations of causal networks for time-series data. We use the expectation maximization algorithm to learn a generative model which captures variations in the causal network over time. We conduct experiments on fMRI brain connectivity data for subjects in different stages of the development of Alzheimer’s disease (AD). Here we use the technique to learn class exemplars for different stages in the development of the disease, together with a normal control class, and demonstrate its utility in both graph multi-class and binary classifications. These experiments are showing the effectiveness of our proposed framework when the amounts of training data are relatively small

Regio- and Stereoselective Synthesis of Tetrasubstituted Alkenes via Ruthenium(II)-Catalyzed C–H Alkenylation/Directing Group Migration

Herein we report the regio- and stereoselective synthesis of tetrasubstituted alkenes from N-carbamoyl indoles and alkynes via ruthenium(II)-catalyzed C−H alkenylation/directing group migration, in which the carbamoyl directing group is endowed with a dual role of auxiliary group and migrating acylation reagent via C−N bond cleavage. This method features broad substrate scope, high atom- and step-economy, good functional group tolerance and mild redox-neutral conditions at room temperature. A series of structurally diverse tetrasubstituted alkenes were synthesized in good to excellent yields, highlighting the efficiency of this method

On Optimal Neighbor Discovery

Mobile devices apply neighbor discovery (ND) protocols to wirelessly initiate a first contact within the shortest possible amount of time and with minimal energy consumption. For this purpose, over the last decade, a vast number of ND protocols have been proposed, which have progressively reduced the relation between the time within which discovery is guaranteed and the energy consumption. In spite of the simplicity of the problem statement, even after more than 10 years of research on this specific topic, new solutions are still proposed even today. Despite the large number of known ND protocols, given an energy budget, what is the best achievable latency still remains unclear. This paper addresses this question and for the first time presents safe and tight, duty-cycle-dependent bounds on the worst-case discovery latency that no ND protocol can beat. Surprisingly, several existing protocols are indeed optimal, which has not been known until now. We conclude that there is no further potential to improve the relation between latency and duty-cycle, but future ND protocols can improve their robustness against beacon collisions.Comment: Conference of the ACM Special Interest Group on Data Communication (ACM SIGCOMM), 201

Additive-Controlled Divergent Synthesis of Tetrasubstituted 1,3-Enynes and Alkynylated 3H-Pyrrolo[1,2-a]indol-3-ones via Rhodium Catalysis

Herein, we report the additive-controlled divergent synthesis of tetrasubstituted 1,3-enynes and alkynylated 3H-pyrrolo[1,2-a]indol-3-ones through rhodium-catalyzed C-H alkenylation/DG migration and [3+2] annulation, respectively. This protocol features rare directing group migration in 1,3-diyne-involved C-H activation, excellent regio- and stereoselectivity, excellent monofunctionalization over difunctionalization, broad substrate scope, moderate to high yields, good functional group compatibility, and mild redox-neutral conditions

Rhodium(III)-Catalyzed C–H Alkenylation/Directing Group Migration for the Regio- and Stereoselective Synthesis of Tetrasubstituted Alkenes

An efficient Rh(III)-catalyzed C-H alkenylation/directing group migration cascade between indoles and alkynes for the assembly of tetrasubstituted alkenes is reported. The carbamoyl directing group migrates to the carbon of the alkene moiety of the products through rare Rh-catalyzed C-N bond cleavage after the C-H alkenylation step and thus acts as an internal amidation reagent. This protocol shows broad substrate scope, excellent regio/stereoselectivity, and good to excellent yields

Temperature-Controlled Divergent Synthesis of Tetrasubstituted Alkenes and Pyrrolo[1,2-a]indole Derivatives via Iridium Catalysis

We have achieved an Ir(III)-catalyzed temperature-controlled divergent synthesis of tetrasubstituted alkenes and pyrrolo[1,2-a]indole derivatives through C−H alkenylation/DG migration and [3+2] annulation, respectively. This method has various advantageous features: a) excellent regio- and stereoselectivity and good functional group tolerance, b) broad substrate scope and moderate to excellent yields, c) mild redox-neutral reaction conditions and operational simplicity

Chemo-, Regio-, and Stereoselective Assembly of Polysubstituted Furan-2(5H)-ones Enabled by Rh(III)-Catalyzed Domino C–H Alkenylation/Directing Group Migration/Lactonization: A Combined Experimental and Computational Study

Exploring multistep cascade reactions triggered by C–H activation are recognized as appealing, yet challenging. Herein, we disclose a Rh(III)-catalyzed domino C–H coupling of N-carbamoyl indoles and 4-hydroxy-2-alkynoates for the streamlined assembly of highly functionalized furan-2(5H)-ones in which the carbamoyl-directing group (DG) is given a dual role of an auxiliary group and a migrating acylating reagent via the cleavage of stable C–N bonds at room temperature. More importantly, the obtained furan-2(5H)-one skeleton could be further functionalized under air in situ via C5–H hydroxylation by simply switching the solvent or additive, providing fully substituted furan-2(5H)-ones with the installation of an alcohol-based C5 quaternary carbon center. Detailed experimental studies and density functional theory calculations reveal that a Rh(III)-mediated tandem C–H activation/alkyne insertion/DG migration/lactonization accounts for the developed transformation to achieve high functionalities with the observed exclusive selectivity. The potential biological application of the obtained furan-2(5H)-ones as a class of potent PPARγ ligands further highlights the synthetic utility of the developed methodology. This protocol is endowed with several salient features including efficient multistep cascade triggered by C–H activation, excellent chemo-, regio-, and stereoselectivity, high bond-forming efficiency (e.g., two C–C and two C–O bonds), solvent- or additive-controlled product selectivity, good functional-group compatibility, and mild redox-neutral conditions

Chemo- and Regioselective Synthesis of Functionalized 1H-imidazo[1,5-a]indol-3(2H)-ones via a Redox-Neutral Rhodium(III)-Catalyzed [4+1] Annulation between Indoles and Alkynes

Alkynes generally serve as C2 synthons in transition-metal-catalyzed C−H annulations, herein, exploiting electron-deficient alkynes as unconventional C1 synthons, the chemo- and regiospecific synthesis of functionalized 1H-imidazo[1,5-a]indol-3(2H)-ones via a redox-neutral rhodium(III)-catalyzed [4+1] annulation of N-carbamoyl indoles has been achieved. This process is characterized by high chemo- and regioselectivity, broad substrate scope, good tolerance of functional groups, moderate to high yields and mild redox-neutral conditions, thus affording a robust approach to access valuable 1H-imidazo[1,5-a]indol-3(2H)-ones

A review on the chemical constituents and pharmacological efficacies of Lindera aggregata (Sims) Kosterm

Lindera aggregata (Sims) Kosterm. (L. aggregata), which belongs to the genus Lindera in the family Lauraceae, is widely distributed in Asia and the temperate, tropical regions of North America. Its roots and leaves have been used for thousands of years as traditional Chinese medicine and/or functional food. To further explore its underlying nutritional value, this review provided a comprehensive insight into chemical constituents and pharmacological effects on L. aggregata. The phytochemical investigation of different parts of L. aggregata led to the identification of up to 349 components belonging to sesquiterpenoids, alkaloids, flavonoids, essential oils, and other compounds. Among them, sesquiterpenoids, flavonoids, and alkaloids are assessed as representative active ingredients of L. aggregata. A wide variety of pharmacological effects of L. aggregata, such as anti-hyperlipidemic, anti-tumor, anti-inflammatory, analgesic, and anti-oxidant, have been proved in vitro and in vivo. In summary, this review aims to provide a scientific basis and reference for further research and utilization of L. aggregata and lay the foundation for developing functional foods with potential active ingredients for the prevention and management of related diseases