Principles for Making Half-center Oscillators and Rules for Torus Bifurcation in Neuron Models

In this modelling work, we adopted geometric slow-fast dissection and parameter continuation approach to study the following three topics: 1. Principles for making the half-center oscillator, a ubiquitous building block for many rhythm-generating neural networks. 2. Causes of a novel electrical behavior of neurons, amplitude modulation, from the view of dynamical systems; 3. Explanation and predictions for two common types of chaotic dynamics in single neuron model. To make our work as general as possible, we used and built both exemplary biologically plausible Hodgkin-Huxley type neuron models and reduced phenomenological neuron models

Integrated Genomic Analysis of the Ubiquitin Pathway across Cancer Types

Protein ubiquitination is a dynamic and reversibleprocess of adding single ubiquitin molecules orvarious ubiquitin chains to target proteins. Here,using multidimensional omic data of 9,125 tumorsamples across 33 cancer types from The CancerGenome Atlas, we perform comprehensive molecu-lar characterization of 929 ubiquitin-related genesand 95 deubiquitinase genes. Among them, we sys-tematically identify top somatic driver candidates,including mutatedFBXW7with cancer-type-specificpatterns and amplifiedMDM2showing a mutuallyexclusive pattern withBRAFmutations. Ubiquitinpathway genes tend to be upregulated in cancermediated by diverse mechanisms. By integratingpan-cancer multiomic data, we identify a group oftumor samples that exhibit worse prognosis. Thesesamples are consistently associated with the upre-gulation of cell-cycle and DNA repair pathways, char-acterized by mutatedTP53,MYC/TERTamplifica-tion, andAPC/PTENdeletion. Our analysishighlights the importance of the ubiquitin pathwayin cancer development and lays a foundation fordeveloping relevant therapeutic strategies

25th annual computational neuroscience meeting: CNS-2016

The same neuron may play different functional roles in the neural circuits to which it belongs. For example, neurons in the Tritonia pedal ganglia may participate in variable phases of the swim motor rhythms [1]. While such neuronal functional variability is likely to play a major role the delivery of the functionality of neural systems, it is difficult to study it in most nervous systems. We work on the pyloric rhythm network of the crustacean stomatogastric ganglion (STG) [2]. Typically network models of the STG treat neurons of the same functional type as a single model neuron (e.g. PD neurons), assuming the same conductance parameters for these neurons and implying their synchronous firing [3, 4]. However, simultaneous recording of PD neurons shows differences between the timings of spikes of these neurons. This may indicate functional variability of these neurons. Here we modelled separately the two PD neurons of the STG in a multi-neuron model of the pyloric network. Our neuron models comply with known correlations between conductance parameters of ionic currents. Our results reproduce the experimental finding of increasing spike time distance between spikes originating from the two model PD neurons during their synchronised burst phase. The PD neuron with the larger calcium conductance generates its spikes before the other PD neuron. Larger potassium conductance values in the follower neuron imply longer delays between spikes, see Fig. 17.Neuromodulators change the conductance parameters of neurons and maintain the ratios of these parameters [5]. Our results show that such changes may shift the individual contribution of two PD neurons to the PD-phase of the pyloric rhythm altering their functionality within this rhythm. Our work paves the way towards an accessible experimental and computational framework for the analysis of the mechanisms and impact of functional variability of neurons within the neural circuits to which they belong

Molecular characterization and clinical relevance of metabolic expression subtypes in human cancers.

Metabolic reprogramming provides critical information for clinical oncology. Using molecular data of 9,125 patient samples from The Cancer Genome Atlas, we identified tumor subtypes in 33 cancer types based on mRNA expression patterns of seven major metabolic processes and assessed their clinical relevance. Our metabolic expression subtypes correlated extensively with clinical outcome: subtypes with upregulated carbohydrate, nucleotide, and vitamin/cofactor metabolism most consistently correlated with worse prognosis, whereas subtypes with upregulated lipid metabolism showed the opposite. Metabolic subtypes correlated with diverse somatic drivers but exhibited effects convergent on cancer hallmark pathways and were modulated by highly recurrent master regulators across cancer types. As a proof-of-concept example, we demonstrated that knockdown of SNAI1 or RUNX1—master regulators of carbohydrate metabolic subtypes-modulates metabolic activity and drug sensitivity. Our study provides a system-level view of metabolic heterogeneity within and across cancer types and identifies pathway cross-talk, suggesting related prognostic, therapeutic, and predictive utility

BiVO4–Deposited MIL–101–NH2 for Efficient Photocatalytic Elimination of Cr(VI)

In this study, a flower–like BiVO4/MIL–101–NH2 composite is synthesized by a facile and surfactant–free process. The –COO−–Bi3+ ionic bond construction was conductive to enhance the interface affinity between BiVO4 and MIL–101–NH2. Due to the highly efficient light capture and sufficient electron traps induced by oxygen vacancies and the formation of a heterostructure, the improved separation and transportation rates of charge carriers are realized. In addition, the MIL–101–NH2/BiVO4 composite is favorable for Cr(VI) photocatalytic removal (91.2%). Moreover, FNBV–3 (Fe/Bi = 0.25) also exhibited an excellent reusability after five cycles

BiVO₄–Deposited MIL–101–NH₂ for Efficient Photocatalytic Elimination of Cr(VI)

In this study, a flower–like BiVO4/MIL–101–NH2 composite is synthesized by a facile and surfactant–free process. The –COO−–Bi3+ ionic bond construction was conductive to enhance the interface affinity between BiVO4 and MIL–101–NH2. Due to the highly efficient light capture and sufficient electron traps induced by oxygen vacancies and the formation of a heterostructure, the improved separation and transportation rates of charge carriers are realized. In addition, the MIL–101–NH2/BiVO4 composite is favorable for Cr(VI) photocatalytic removal (91.2%). Moreover, FNBV–3 (Fe/Bi = 0.25) also exhibited an excellent reusability after five cycles

Results and Analysis

In this chapter the experimental results of this thesis will be shown and the related analysis explained. Four topological insulator crystals (Bi2Se3, Bi2-xCaxSe3, Bi2Se2Te and Bi2Te2Se) have been optically studied by FTIR Spectroscopy, with increasing chemical compensation. They have been measured from 5 to 300K and from subterahertz to visible frequencies. The effect of compensation is clearly observed in the infrared spectra through the suppression of the extrinsic Drude term together with the appearance of strong absorption peaks, that we assign to electronic transitions among localized impurities states. From the far-infrared spectral weight of the most compensated sample (Bi2Te2Se), one can estimate a density of charge carriers on the order of 10(17) cm10(-3) in good agreement with transport data. Those results demonstrate that the low electrodynamics in single crystals of TI, even at the highest degree of compensation presently achieved, is still influenced by three-dimensional charge excitations. Its spectral weight is, indeed, still nearly higher by two orders of magnitude than that expected from the topological surface states, estimated from optical conductivity of films of Bi2Se3 on sapphire substrate. Such films have been measured in the sub-THz and THz frequency region, in order to study their optical conductivity as a function of their thickness. One can observe no appreciable change in the free carriers contribution, while the a phonon intensity strongly decreases with decreasing thickness, demonstrating that the only contribution to the transport is due to surface carriers, not depending on bulk characteristics. The surface metallic state of the thin TI films has been finally studied by patterning the films by a grating, as explained in Chap. 2. This provides the possibility to detect surface plasmonic collective modes, due to the excitation of two dimensional charge density waves along the topological interface of the samples. In the last part of this thesis those plasmons will be analyzed, demonstrating that they have two dimensional nature characteristic of 2DEG