Testing Between Different Types of Poisson Mixtures with Applications to Neuroscience

We propose a hypothesis testing for different types of stochastic order of mixture distributions (PRML classifier) and a hypothesis testing for screening out data with mixture distributions (PRML filter), in a Bayesian framework using a recursive algorithm called predictive recursion marginal likelihood (PRML) algorithm. Of particular interest is the special case of testing between different types of Poisson mixtures and testing Poisson distribution versus Poisson mixtures. The first testing procedure applies Laplace approximation coupled with optimization algorithm. This testing helps neuroscientists to classify the activation patterns that a single neuron exhibits when preserving information from multiple stimuli. The second testing aims to screen out over-dispersed data to boost the scientific information. Simulation shows the new classifier and filter outperform the previous testing especially for over-dispersed data. We apply the PRML classifier on the analysis of inferior colliculus neurons filtered by PRML filter. We show the PRML classifier emphasizes second order stochasticity. We present empirical evidence that the PRML filter contributes to avoid mistaking trial-to-trial variation as second order stochasticity.</p

Identifying World Events in Dynamic International Relations Data Using a Latent Space Model

Dynamic network data have become ubiquitous in social network analysis, with new information becoming available that captures when friendships form, when corporate transactions happen and when countries interact with each other. Flexible and interpretable models are needed in order to properly capture the behavior of individuals in such networks. In this paper, we focus on study the underlying latent space that describes the social properties of a dynamic and directed international relations network of countries. We extend the directed additive and multiplicative effects network model to the continuous time setting by treating the time-evolution of model parameters using Gaussian processes. Importantly we incorporate both time-varying covariates and node-level additive random effects that aid in increasing model realism. We demonstrate the usefulness and flexibility of this model on a longitudinal dataset of formal state visits between the world's 18 largest economies. Not only does the model offer high quality predictive accuracy, but the latent parameters naturally map onto world events that are not directly measured in the data

Local Ties, Trans-Local Ties, and Substance Use among Rural-to-Urban Migrants in China

China has witnessed unprecedented rural-to-urban migration since the early 1980s. While trying to assimilate into the city, rural-to-urban migrants still maintain close ties with their home communities. This study examines how local ties and trans-local ties of rural-to-urban migrants affect their alcohol and tobacco use. Data were obtained from the 2016 and 2018 China Labor-force Dynamics Survey, a nationally representative sample of adults aged over 15 in 29 provinces in China. Participants included 1426 rural-to-urban migrant workers and 6438 urban residents in China. We found that compared to urban natives, rural-to-urban migrants had higher tobacco use prevalence (logit = 0.19, 95% CI = [0.03, 0.35]; p &lt; 0.05) and more frequent alcohol use (logit = 0.27, 95% CI = [0.11, 0.42]; p &lt; 0.001) after adjusting for sociodemographic characteristics. Migrants with more local social ties engaged in more frequent drinking (having &gt;10 local friends vs. having 0 local friends: logit = 0.58, [0.10, 1.06], p &lt; 0.05), whereas trans-local ties were not a significant correlate. In contrast, migrants who returned to their hometown more times (an indicator of trans-local ties) were more likely to be current tobacco users (logit = 0.01, 95% CI = [0.00, 0.02], p &lt; 0.01) after adjusting for sociodemographic variables. These findings extended the research on social networks and health behaviors by identifying how local and trans-local ties differentially affected the vulnerabilities of tobacco and alcohol use among rural-to-urban migrants in China. The findings suggested that policies and interventions on reducing migrants&rsquo; health risk behaviors should focus on the role of different types of social ties

The enhanced high-temperature oxidation resistance of additively manufactured GH4169 by adding small amounts of 304L

Enhancing the high-temperature oxidation resistance of nickel-based alloys is critical for expanding their industrial applications. Herein, we report a novel strategy for enhancing the high-temperature oxidation resistance of the GH4169 nickel-based alloy by adding small amounts of 304L stainless steel using selective laser melting technology. The oxidation property of GH4169 with various 304L additions (2 wt.%, 4 wt.%, and 6 wt.%) at 900 °C for 45 h was investigated. Results show that the addition of 304L significantly improves the oxidation resistance of GH4169. The thickness of the oxide film and the intergranular oxidation depth of GH4169 with 6 wt.% 304L added are reduced by 61% and 69%, respectively. The addition of 304L increases Cr and decreases Ni in the matrix, which facilitates the formation of a more compact oxide film. The Nb in Laves phase will be increased with 304L addition, which effectively inhibits oxygen penetration and metallic element diffusion

Evaluation of the Anticancer Activity and Mechanism Studies of Glycyrrhetic Acid Derivatives toward HeLa Cells

In this paper, a series of glycyrrhetic acid derivatives 3a–3f were synthesized via the esterification reaction. The cytotoxicity of these compounds against five tumor cells (SGC-7901, BEL-7402, A549, HeLa and B16) and normal LO2 cells was investigated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. The results showed that compound 3a exhibited high antiproliferative activity against HeLa cells (IC50 = 11.4 ± 0.2 μM). The anticancer activity was studied through apoptosis, cloning, and scratching; the levels of the intracellular ROS, GSH, and Ca2+; and the change in the mitochondrial membrane potential, cell cycle arrest and RNA sequencing. Furthermore, the effects of compound 3a on gene expression levels and metabolic pathways in HeLa cells were investigated via transcriptomics. The experimental results showed that this compound can block the cell cycle in the S phase and inhibit cell migration by downregulating Focal adhesion kinase (FAK) expression. Moreover, the compound can reduce the intracellular glutathione (GSH) content, increase the Ca2+ level and the intracellular ROS content, and induce a decrease in the mitochondrial membrane potential, further leading to cell death. In addition, it was also found that the mechanism of compounds inducing apoptosis was related to the regulation of the expression of mitochondria-related proteins B-cell lymphoma-2 (Bcl-2), Bcl-2-Associated X (Bax), and the activation of the caspase proteins. Taken together, this work provides a help for the development of glycyrrhetinic acid compounds as potential anticancer molecules

A novel fixed-combination timolol-netarsudil-latanoprost ophthalmic solution for the treatment of glaucoma and ocular hypertension

Currently commercial fixed-concomitant three agents have multiple problems such as multiple dosing administration, poor efficacy and side effects. Once-daily fixed-combination timolol-netarsudil-latanoprost ophthalmic solution (FC-TNL) has the ability to treat glaucoma by lowering the intraocular pressure (IOP) with great efficacy and improving patient compliance. However, the commercialized netarsudil dimesylate precipitated when the pH of the solution was above 5.4, or when maleic acid, the salt of commercial timolol maleate, was mixed with netarsudil dimesylate. Consequently, the homologous salt engineering strategy was used to make netarsudil dimesylate soluble in pH 4.8–5.2 solution by synthesizing timolol mesylate. Next, the morphology of timolol mesylate was observed by scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and powder X-ray diffraction. The prepared FC-TNL showed good stability during refrigeration storage. Additionally, FC-TNL exerted no influence on the intraocular penetration of each active compounds in the pharmacokinetic study. Importantly, once-daily FC-TNL exerted potent IOP-lowering effect and protective effect on retinal ganglion cells. The FC-TNL was stable, safe and effective, being a promising glaucoma therapeutic

Multiple objects evoke fluctuating responses in several regions of the visual pathway

How neural representations preserve information about multiple stimuli is mysterious. Because tuning of individual neurons is coarse (e.g., visual receptive field diameters can exceed perceptual resolution), the populations of neurons potentially responsive to each individual stimulus can overlap, raising the question of how information about each item might be segregated and preserved in the population. We recently reported evidence for a potential solution to this problem: when two stimuli were present, some neurons in the macaque visual cortical areas V1 and V4 exhibited fluctuating firing patterns, as if they responded to only one individual stimulus at a time (Jun et al., 2022). However, whether such an information encoding strategy is ubiquitous in the visual pathway and thus could constitute a general phenomenon remains unknown. Here, we provide new evidence that such fluctuating activity is also evoked by multiple stimuli in visual areas responsible for processing visual motion (middle temporal visual area, MT), and faces (middle fundus and anterolateral face patches in inferotemporal cortex – areas MF and AL), thus extending the scope of circumstances in which fluctuating activity is observed. Furthermore, consistent with our previous results in the early visual area V1, MT exhibits fluctuations between the representations of two stimuli when these form distinguishable objects but not when they fuse into one perceived object, suggesting that fluctuating activity patterns may underlie visual object formation. Taken together, these findings point toward an updated model of how the brain preserves sensory information about multiple stimuli for subsequent processing and behavioral action

Multiple objects evoke fluctuating responses in several regions of the visual pathway

How neural representations preserve information about multiple stimuli is mysterious. Because tuning of individual neurons is coarse (e.g., visual receptive field diameters can exceed perceptual resolution), the populations of neurons potentially responsive to each individual stimulus can overlap, raising the question of how information about each item might be segregated and preserved in the population. We recently reported evidence for a potential solution to this problem: when two stimuli were present, some neurons in the macaque visual cortical areas V1 and V4 exhibited fluctuating firing patterns, as if they responded to only one individual stimulus at a time (Jun et al., 2022). However, whether such an information encoding strategy is ubiquitous in the visual pathway and thus could constitute a general phenomenon remains unknown. Here, we provide new evidence that such fluctuating activity is also evoked by multiple stimuli in visual areas responsible for processing visual motion (middle temporal visual area, MT), and faces (middle fundus and anterolateral face patches in inferotemporal cortex – areas MF and AL), thus extending the scope of circumstances in which fluctuating activity is observed. Furthermore, consistent with our previous results in the early visual area V1, MT exhibits fluctuations between the representations of two stimuli when these form distinguishable objects but not when they fuse into one perceived object, suggesting that fluctuating activity patterns may underlie visual object formation. Taken together, these findings point toward an updated model of how the brain preserves sensory information about multiple stimuli for subsequent processing and behavioral action