Modelling human choices: MADeM and decision‑making

Research supported by FAPESP 2015/50122-0 and DFG-GRTK 1740/2. RP and AR are also part of the Research, Innovation and Dissemination Center for Neuromathematics FAPESP grant (2013/07699-0). RP is supported by a FAPESP scholarship (2013/25667-8). ACR is partially supported by a CNPq fellowship (grant 306251/2014-0)

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

Continuous ion separation via electrokinetic-driven ion migration path differentiation: practical application to lithium extraction from brines

The effective separation of Mg2+ from Li+ is the key for realizing efficient and economic lithium extraction from brine, but remains challenging due to their similar chemical properties. Recent approaches have enabled simultaneous magnesium removal and lithium extraction from high Mg2+/Li+ ratio brines, but their reliance on physical or chemical filters has led to inconsistent performance dependent on brine conditions and corresponding limitations in their cost-effectiveness and scalability. Despite Mg2+'s and Li+'s kindred properties, a subtle difference in their electrophoretic mobilities has allowed for the development of the herein proposed new ion separation method for continuous lithium extraction from high Mg2+/Li+ ratio brines utilizing electrokinetic manipulation of ion migrations. This is the first experimental demonstration of a filterless and force-based ion separation method that works by steering ions onto different paths simply by balancing the diagonally formed electric field intensity and flow rate, and realized by introducing a highly scalable electrokinetic system equipped with a multiscale-porous anion exchange membrane. The effects of core operating parameters as well as brine conditions on system performance are elaborated through experimental studies. Remarkably, consistent performance can be achieved in this system regardless of brine conditions by virtue of the filterless lithium extraction mechanism. This work offers a novel strategy to precisely modulate ion migrations in an aqueous solution and furthers progress toward both active ion manipulation and practical and economic lithium mining from different types of lithium-containing brines.11Nsciescopu

Bezier curve smoothing of the Kaplan-Meier estimator

Bandwidth, censored data, kernel smoothing, strong consistency,

Effect of whole-brain radiotherapy with platinum-based chemotherapy in non-small cell lung cancer patients with multiple metastases including brain metastases

Abstract Current guidelines recommend that cytotoxic chemotherapy be considered first in non-small cell lung cancer (NSCLC) patients with multiple metastases, and whole-brain radiotherapy (WBRT) is not initially recommended even if brain metastases are present. However, cytotoxic chemotherapeutic agents are less effective in brain metastases due to poor blood–brain barrier permeability. We investigated the effect of WBRT in combination with cytotoxic chemotherapy on survival in NSCLC patients who were EGFR, ALK, and PD-L1 negative, had an ECOG PS of 2, and had multiple metastases including brain metastases. From January 2005 to December 2018, histologically confirmed NSCLC patients who were EGFR, ALK, and PD-L1 negative, had an ECOG PS of 2, and had multiple metastases including brain metastases were included in this study. Patients were classified into two groups based on receiving WBRT prior to or concurrently with administration of first-line chemotherapeutic agents or receiving chemotherapy only. We compared intracranial progression-free survival (iPFS) and overall survival (OS). Of the 240 NSCLC patients with brain metastases at diagnosis and an ECOG PS of 2, 67 patients were EGFR, ALK, and PD-L1 negative with multiple metastases including brain metastases. Among those patients, 43 (64.2%) received WBRT prior to or concurrently with platinum-based chemotherapy. Patients who received WBRT prior to or concurrently with chemotherapy had better iPFS (7.7 months [4.8–10.6] vs. 3.5 months [2.1–4.9], p = 0.009) and OS (10.8 months [5.9–15.7] vs. 6.1 months [1.9–10.3], p = 0.038) than those who did not receive WBRT. In multivariate analyses, WBRT was significantly associated with iPFS (HR: 1.94 and 95% CI 1.11–3.40, p = 0.020) and OS (HR: 1.92 and 95% CI 1.08–3.42, p = 0.027). In NSCLC patients who are EGFR, ALK, and PD-L1 negative, have an ECOG PS of 2, and have multiple metastases including brain metastases, WBRT prior to or concurrently with chemotherapy could improve iPFS and OS. Therefore, the combination of WBRT with cytotoxic chemotherapy should be considered in these patients

A gigantically increased ratio of electrical to thermal conductivity and synergistically enhanced thermoelectric properties in interface-controlled TiO2-RGO nanocomposites

We report synergistically enhanced thermoelectric properties through the independently controlled charge and thermal transport properties in a TiO2-reduced graphene oxide (RGO) nanocomposite. By the consolidation of TiO2-RGO hybrid powder using spark plasma sintering, we prepared an interfacecontrolled TiO2-RGO nanocomposite where its grain boundaries are covered with the RGO network. Both the enhancement in electrical conductivity and the reduction in thermal conductivity were simultaneously achieved thanks to the beneficial effects of the RGO network, and detailed mechanisms are discussed. This led to the gigantic increase in the ratio of electrical to thermal conductivity by six orders of magnitude and also the synergistic enhancement in the thermoelectric figure of merit by two orders. Our results present a strategy for the realization of 'phonon-glass electron-crystals' through interface control using graphene in graphene hybrid thermoelectric materials © The Royal Society of Chemistry1321sciescopu

Thermal Transport in Silicon Nanowires at High Temperature up to 700 K

Thermal transport in silicon nanowires has captured the attention of scientists for understanding phonon transport at the nanoscale, and the thermoelectric figure-of-merit (ZT) reported in rough nanowires has inspired engineers to develop cost-effective waste heat recovery systems. Thermoelectric generators composed of silicon target high-temperature applications due to improved efficiency beyond 550 K. However, there have been no studies of thermal transport in silicon nanowires beyond room temperature. High-temperature measurements also enable studies of unanswered questions regarding the impact of surface boundaries and varying mode contributions as the highest vibrational modes are activated (Debye temperature of silicon is 645 K). Here, we develop a technique to investigate thermal transport in nanowires up to 700 K. Our thermal conductivity measurements on smooth silicon nanowires show the classical diameter dependence from 40 to 120 nm. In conjunction with Boltzmann transport equation, we also probe an increasing contribution of high-frequency phonons (optical phonons) in smooth silicon nanowires as the diameter decreases and the temperature increases. Thermal conductivity of rough silicon nanowires is significantly reduced throughout the temperature range, demonstrating a potential for efficient thermoelectric generation (e.g., ZT = 1 at 700 K)

MicroRNA 34a–AXL Axis Regulates Vasculogenic Mimicry Formation in Breast Cancer Cells

Targeting the tumor vasculature is an attractive strategy for cancer treatment. However, the tumor vasculature is heterogeneous, and the mechanisms involved in the neovascularization of tumors are highly complex. Vasculogenic mimicry (VM) refers to the formation of vessel-like structures by tumor cells, which can contribute to tumor neovascularization, and is closely related to metastasis and a poor prognosis. Here, we report a novel function of AXL receptor tyrosine kinase (AXL) in the regulation of VM formation in breast cancer cells. MDA-MB-231 cells exhibited VM formation on Matrigel cultures, whereas MCF-7 cells did not. Moreover, AXL expression was positively correlated with VM formation. Pharmacological inhibition or AXL knockdown strongly suppressed VM formation in MDA-MB-231 cells, whereas the overexpression of AXL in MCF-7 cells promoted VM formation. In addition, AXL knockdown regulated epithelial–mesenchymal transition (EMT) features, increasing cell invasion and migration in MDA-MB-231 cells. Finally, the overexpression of microRNA-34a (miR-34a), which is a well-described EMT-inhibiting miRNA and targets AXL, inhibited VM formation, migration, and invasion in MDA-MB 231 cells. These results identify a miR-34a–AXL axis that is critical for the regulation of VM formation and may serve as a therapeutic target to inhibit tumor neovascularization