20,474 results match your criteria discrete model


Conventional type I dendric cells maintain a reservoir of proliferative tumor-antigen specific TCF-1 CD8 T cells in tumor-draining lymph nodes.

Immunity 2021 Sep 8. Epub 2021 Sep 8.

David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, MA 02139, USA; Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA. Electronic address:

In tumors, a subset of CD8 T cells expressing the transcription factor TCF-1 drives the response to immune checkpoint blockade. We examined the mechanisms that maintain these cells in an autochthonous model of lung adenocarcinoma. Longitudinal sampling and single-cell sequencing of tumor-antigen specific TCF-1 CD8 T cells revealed that while intratumoral TCF-1 CD8 T cells acquired dysfunctional features and decreased in number as tumors progressed, TCF-1 CD8 T cell frequency in the tumor draining LN (dLN) remained stable. Read More

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September 2021

Macro and micro analysis on coal-bearing soil slopes instability based on CFD-DEM coupling method.

PLoS One 2021 17;16(9):e0257362. Epub 2021 Sep 17.

School of Civil and Architectural Engineering, Nanchang Institute of Technology, Nanchang, China.

By combining the discrete element method (DEM) with computational fluid dynamics (CFD), this study proposes a three-dimensional CFD-DEM fluid-solid coupling microscopic computational model for analyzing the micromechanisms of instability and failure in a coal-bearing soil slope during rainfall. The CFD-DEM fluid-solid coupling model indicated that the main failure mode of the coal-bearing soil slopes was rainwater washing, and the slope sliding surface was predicted as an approximately linear segment. The adaptability of this numerical method was verified by comparing its results with those of rain-washed slopes in an outdoor model test. Read More

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September 2021

Using latent class and quantum models to value equity in health care: a tale of 2 stories.

J Manag Care Spec Pharm 2021 Sep;27(9-a Suppl):S14-S18

Department of Health Outcomes Research & Policy, Harrison School of Pharmacy, Auburn University, Auburn, AL.

Cost-effectiveness analysis (CEA) with quality-adjusted life-year (QALY) was introduced to address health equity concerns in value assessment. However, QALY fails to capture patient preference. Stated preference methods (eg, discrete choice experiment [DCE]) have been increasingly used to incorporate patient preference into the value assessment framework in health care. Read More

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September 2021

Discrete dynamical models on infection frequency in mosquito populations with biased release ratios.

Authors:
Yantao Shi Bo Zheng

J Biol Dyn 2021 Sep 17:1-20. Epub 2021 Sep 17.

College of Mathematics and Information Sciences, Guangzhou University, Guangzhou, People's Republic of China.

We develop two discrete models to study how supplemental releases affect the spreading dynamics in cage mosquito populations. The first model focuses on the case when only infected males are released at each generation. This release strategy has been proved to be capable of speeding up the persistence by suppressing the compatible matings between uninfected individuals. Read More

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September 2021

Integrating animal movements with phylogeography to model the spread of PRRSV in the USA.

Virus Evol 2021 15;7(2):veab060. Epub 2021 Jul 15.

Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, Minneapolis, 1365 Gortner Avenue, St. Paul, MN, 55108, USA.

Viral sequence data coupled with phylodynamic models have become instrumental in investigating the outbreaks of human and animal diseases, and the incorporation of the hypothesized drivers of pathogen spread can enhance the interpretation from phylodynamic inference. Integrating animal movement data with phylodynamics allows us to quantify the extent to which the spatial diffusion of a pathogen is influenced by animal movements and contrast the relative importance of different types of movements in shaping pathogen distribution. We combine animal movement, spatial, and environmental data in a Bayesian phylodynamic framework to explain the spatial diffusion and evolutionary trends of a rapidly spreading sub-lineage (denoted L1A) of porcine reproductive and respiratory syndrome virus (PRRSV) Type 2 from 2014 to 2017. Read More

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A model based on cellular automata for investigating the impact of lockdown, migration and vaccination on COVID-19 dynamics.

Authors:
P K Jithesh

Comput Methods Programs Biomed 2021 Sep 13;211:106402. Epub 2021 Sep 13.

Assistant Professor in Mechanical Engineering, Government Engineering College Kozhikode, Westhill Post, Kozhikode, Kerala 673005, India.

Background And Objective: COVID-19 pandemic continues unabated due to the rapid spread of new mutant strains of the virus. Decentralized cluster containment is an efficient approach to manage the pandemic in the long term, without straining the healthcare system and economy. In this study, the objective is to forecast the peak and duration of COVID-19 spread in a cluster under different conditions, using a probabilistic cellular automata configuration designed to include the observed characteristics of the pandemic with appropriate neighbourhood schemes and transition rules. Read More

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September 2021

The Design Principles of Discrete Turing Patterning Systems.

J Theor Biol 2021 Sep 13:110901. Epub 2021 Sep 13.

Department of Life Sciences, Imperial College, London, UK; Melbourne Interated Genomics, University of Melbourne, Australia; School of BioScience, University of Melbourne, Australia; School of Mathematics and Statistics, University of Melbourne, Australia. Electronic address:

The formation of spatial structures lies at the heart of developmental processes. However, many of the underlying gene regulatory and biochemical processes remain poorly understood. Turing patterns constitute a main candidate to explain such processes, but they appear sensitive to fluctuations and variations in kinetic parameters, raising the question of how they may be adopted and realised in naturally evolved systems. Read More

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September 2021

A network model of transient polymers: exploring the micromechanics of nonlinear viscoelasticity.

Soft Matter 2021 Sep 16. Epub 2021 Sep 16.

Department of Mechanical Engineering, Program of Materials Science and Engineering, University of Colorado, Boulder, USA.

Dynamic networks contain crosslinks that re-associate after disconnecting, imparting them with viscoelastic properties. While continuum approaches have been developed to analyze their mechanical response, these approaches can only describe their evolution in an average sense, omitting local, stochastic mechanisms that are critical to damage initiation or strain localization. To address these limitations, we introduce a discrete numerical model that mesoscopically coarse-grains the individual constituents of a dynamic network to predict its mechanical and topological evolution. Read More

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September 2021

Single-cell RNA-seq profiling of mouse endothelial cells in response to pulmonary arterial hypertension.

Cardiovasc Res 2021 Sep 16. Epub 2021 Sep 16.

The Queen's Medical Research Institute, Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, EH16 4TJ, UK.

Aims: Endothelial cell dysfunction drives the initiation and pathogenesis of pulmonary arterial hypertension (PAH). We aimed to characterise endothelial cell (EC) dynamics in PAH at single-cell resolution.

Methods And Results: We carried out single-cell RNA sequencing (scRNA-seq) of lung ECs isolated from an EC lineage-tracing mouse model in Control and SU5416/Hypoxia-induced PAH conditions. Read More

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September 2021

Detection of homolog-independent meiotic DNA repair events in with the intersister/intrachromatid repair assay.

STAR Protoc 2021 Sep 8;2(3):100801. Epub 2021 Sep 8.

Institute of Molecular Biology, Department of Biology, University of Oregon, 1229 Franklin Boulevard, Eugene, OR 97403, USA.

Accurate repair of DNA double-strand breaks (DSBs) in developing germ cells is critical to promote proper chromosome segregation and to maintain genome integrity. To directly detect homolog-independent (intersister/intrachromatid) meiotic DSB repair, we exploited the genetics and germline physiology of to (1) induce a single DSB in nuclei across discrete stages of meiotic prophase I; (2) detect repair of that DSB as a homolog-independent crossover or noncrossover; and (3) sequence the resultant product to assess mechanisms of recombination. For complete details on the use and execution of this protocol, please refer to Toraason et al. Read More

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September 2021

Different Influence of Negative and Positive Spillover between Work and Life on Depression in a Longitudinal Study.

Saf Health Work 2021 Sep 11;12(3):377-383. Epub 2021 May 11.

Human Rights Center, Seoul National University Hospital, Seoul, Republic of Korea.

Background: This study investigated the longitudinal associations between the degrees of positive and negative spillover in work-life balance (WLB) at baseline and reports of depressive mood at a 2-year follow-up in Korean women employees.

Methods: We used a panel study design data of 1386 women employees who participated in the Korean Longitudinal Survey of Women and Families in both 2014 and 2016. Depressive mood was measured using the "10-item Center for Epidemiologic Studies Depression Scale. Read More

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September 2021

Deep learning identifies synergistic drug combinations for treating COVID-19.

Proc Natl Acad Sci U S A 2021 Sep;118(39)

Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA 02139.

Effective treatments for COVID-19 are urgently needed. However, discovering single-agent therapies with activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been challenging. Combination therapies play an important role in antiviral therapies, due to their improved efficacy and reduced toxicity. Read More

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September 2021

Breakdown of random matrix universality in Markov models.

Phys Rev E 2021 Aug;104(2-1):024305

Department of Physics, Ryerson University, M5B 2K3, Toronto, Canada.

Biological systems need to react to stimuli over a broad spectrum of timescales. If and how this ability can emerge without external fine-tuning is a puzzle. We consider here this problem in discrete Markovian systems, where we can leverage results from random matrix theory. Read More

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Novel Discrete-Time Recurrent Neural Network for Robot Manipulator: A Direct Discretization Technical Route.

IEEE Trans Neural Netw Learn Syst 2021 Sep 15;PP. Epub 2021 Sep 15.

Controlling and processing of time-variant problem is universal in the fields of engineering and science, and the discrete-time recurrent neural network (RNN) model has been proven as an effective method for handling a variety of discrete time-variant problems. However, such model usually originates from the discretization research of continuous time-variant problem, and there is little research on the direct discretization method. To address the aforementioned problem, this article introduces a novel discrete-time RNN model for solving the discrete time-variant problem in a pioneering manner. Read More

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September 2021

An approximate quasi-likelihood approach for error-prone failure time outcomes and exposures.

Stat Med 2021 Oct 22;40(23):5006-5024. Epub 2021 Jun 22.

Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA.

Measurement error arises commonly in clinical research settings that rely on data from electronic health records or large observational cohorts. In particular, self-reported outcomes are typical in cohort studies for chronic diseases such as diabetes in order to avoid the burden of expensive diagnostic tests. Dietary intake, which is also commonly collected by self-report and subject to measurement error, is a major factor linked to diabetes and other chronic diseases. Read More

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October 2021

On the timing of interventions to preserve hospital capacity: lessons to be learned from the Belgian SARS-CoV-2 pandemic in 2020.

Arch Public Health 2021 Sep 13;79(1):164. Epub 2021 Sep 13.

Spatial Epidemiology Laboratory, Université Libre de Bruxelles, Brussels, Belgium.

Using publicly available data on the number of new hospitalisations we use a newly developed statistical model to produce a phase portrait to monitor the epidemic allowing for assessing whether or not intervention measures are needed to keep hospital capacity under control. The phase portrait is called a cliquets' diagram, referring to the discrete alarm phases it points to. Using this cliquets' diagram we show that intervention measures were associated with an effective mitigation of a Summer resurgence but that too little too late was done to prevent a large autumn wave in Belgium. Read More

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September 2021

Modular Lipoprotein Toxins Transferred by Outer Membrane Exchange Target Discrete Cell Entry Pathways.

mBio 2021 Sep 14:e0238821. Epub 2021 Sep 14.

Department of Molecular Biology, University of Wyominggrid.135963.b, Laramie, Wyoming, USA.

Bacteria compete against related individuals by delivering toxins. In myxobacteria, a key delivery and kin discrimination mechanism is called outer membrane (OM) exchange (OME). Here, cells that display compatible polymorphic cell surface receptors recognize one another and bidirectionally transfer OM content. Read More

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September 2021

The risk of future waves of COVID-19: modeling and data analysis.

Math Biosci Eng 2021 06;18(5):5409-5426

Department of Mathematics, University of Florida, Gainesville, 32611, USA.

After a major outbreak of the coronavirus disease (COVID-19) starting in late December 2019, there were no new cases reported in mainland China for the first time on March 18, 2020, and no new cases reported in Hong Kong Special Administrative Region on April 20, 2020. However, these places had reported new cases and experienced a second wave since June 11, 2020. Here we develop a stochastic discrete-time epidemic model to evaluate the risk of COVID-19 resurgence by analyzing the data from the beginning of the outbreak to the second wave in these three places. Read More

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Effect of swirling flow and particle-release pattern on drug delivery to human tracheobronchial airways.

Biomech Model Mechanobiol 2021 Sep 13. Epub 2021 Sep 13.

School of Aerospace Engineering, Huazhong University of Science and Technology, Wuhan, China.

The present study aims to investigate the effect of swirling flow on particle deposition in a realistic human airway. A computational fluid dynamic (CFD) model was utilized for the simulation of oral inhalation and particle transport patterns, considering the k-ω turbulence model. Lagrangian particle tracking was used to track the particles' trajectories. Read More

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September 2021

Preferences for biologic treatment in patients with psoriatic arthritis: a discrete choice experiment.

Arthritis Care Res (Hoboken) 2021 Sep 13. Epub 2021 Sep 13.

Sydney School of Public Health, University of Sydney, Sydney, 2006.

Objectives: We aimed to assess patient preferences for the characteristics and outcomes of biologic and targeted synthetic DMARDs to manage psoriatic arthritis.

Methods: We conducted a discrete choice experiment in patients with psoriatic arthritis from three rheumatology centers in Sydney, Australia. We assessed preferences for different attributes of biologic medications. Read More

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September 2021

Local tissue heterogeneity may modulate neuronal responses via altered axon strain fields: insights about innervated joint capsules from a computational model.

Biomech Model Mechanobiol 2021 Sep 12. Epub 2021 Sep 12.

Department of Biomedical Engineering, College of Science and Engineering, University of Minnesota, Nils Hasselmo Hall, 312 Church St SE, Minneapolis, MN, USA.

In innervated collagenous tissues, tissue scale loading may contribute to joint pain by transmitting force through collagen fibers to the embedded mechanosensitive axons. However, the highly heterogeneous collagen structures of native tissues make understanding this relationship challenging. Recently, collagen gels with embedded axons were stretched and the resulting axon signals were measured, but these experiments were unable to measure the local axon strain fields. Read More

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September 2021

Dueling emergencies: Flood evacuation ridesharing during the COVID-19 pandemic.

Transp Res Interdiscip Perspect 2021 Jun 1;10:100352. Epub 2021 Apr 1.

Department of Civil and Environmental Engineering, Northwestern University, Technological Institute, 2145 Sheridan Road, Evanston, IL 60208, USA.

Volunteered sharing of resources is often observed in response to disaster events. During evacuations the sharing of resources and vehicles is a crucial mechanism for expanding critical capacity and enabling inclusive disaster response. This paper examines the complexity of rideshare decision-making in the wake of simultaneous emergencies. Read More

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Dynamic activity chain pattern estimation under mobility demand changes during COVID-19.

Transp Res Part C Emerg Technol 2021 Oct 25;131:103361. Epub 2021 Aug 25.

School of Electronic and Information Engineering, Beihang University, Beijing 100191, PR China.

During the coronavirus disease 2019 pandemic, the activity engagement and travel behavior of city residents have been impacted by government restrictions, such as temporary city-wide lockdowns, the closure of public areas and public transport suspension. Based on multiple heterogeneous data sources, which include aggregated mobility change reports and household survey data, this paper proposes a machine learning approach for dynamic activity chain pattern estimation with improved interpretability for examining behavioral pattern adjustments. Based on historical household survey samples, we first establish a computational graph-based discrete choice model to estimate the baseline travel tour parameters before the pandemic. Read More

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October 2021

Novel Oral Iron Therapy for Iron Deficiency: How to Value Safety in a New Drug?

Br J Clin Pharmacol 2021 Sep 12. Epub 2021 Sep 12.

Centre for Health Economics and Medicines Evaluation, Bangor University.

Objective: Novel oral iron supplements may be associated with a reduced incidence of adverse drug reactions compared to standard treatments of iron deficiency anaemia. The aim was to establish their value-based price under conditions of uncertainty surrounding their tolerability.

Methods: A discrete-time Markov model was developed to assess the value-based price of oral iron preparations based on their incremental cost per quality-adjusted life year (QALY) gained from the perspective of the NHS in the UK. Read More

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September 2021

Metabolic requirements of NK cells during the acute response against retroviral infection.

Nat Commun 2021 09 10;12(1):5376. Epub 2021 Sep 10.

School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin, 2, Ireland.

Natural killer (NK) cells are important early responders against viral infections. Changes in metabolism are crucial to fuel NK cell responses, and altered metabolism is linked to NK cell dysfunction in obesity and cancer. However, very little is known about the metabolic requirements of NK cells during acute retroviral infection and their importance for antiviral immunity. Read More

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September 2021

AI enabled sign language recognition and VR space bidirectional communication using triboelectric smart glove.

Nat Commun 2021 Sep 10;12(1):5378. Epub 2021 Sep 10.

Department of Electrical & Computer Engineering, National University of Singapore, Singapore, Singapore.

Sign language recognition, especially the sentence recognition, is of great significance for lowering the communication barrier between the hearing/speech impaired and the non-signers. The general glove solutions, which are employed to detect motions of our dexterous hands, only achieve recognizing discrete single gestures (i.e. Read More

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September 2021

All-or-none disconnection of pyramidal inputs onto parvalbumin-positive interneurons gates ocular dominance plasticity.

Proc Natl Acad Sci U S A 2021 Sep;118(37)

Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218;

Disinhibition is an obligatory initial step in the remodeling of cortical circuits by sensory experience. Our investigation on disinhibitory mechanisms in the classical model of ocular dominance plasticity uncovered an unexpected form of experience-dependent circuit plasticity. In the layer 2/3 of mouse visual cortex, monocular deprivation triggers a complete, "all-or-none," elimination of connections from pyramidal cells onto nearby parvalbumin-positive interneurons (Pyr→PV). Read More

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September 2021

Public preferences for the allocation of donor organs for transplantation: A discrete choice experiment.

Soc Sci Med 2021 Sep 3;287:114360. Epub 2021 Sep 3.

Institute for Epidemiology, Social Medicine and Health Systems Research, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany; Center for Health Economics Research Hannover (CHERH), Otto-Brenner-Str. 7, 30159, Hannover, Germany. Electronic address:

This study aimed to assess public preferences for the allocation of donor organs in Germany with the focus on ethical principles of distributive justice. We performed a discrete choice experiment (DCE) using a self-completed online questionnaire. Based on a systematic review and focus group discussions, six attributes, each with two-four levels, were selected (corresponding principle of distributive justice in brackets), including (1) life years gained after transplantation (principle of distributive justice: effectiveness/benefit - utilitarianism), (2) quality of life after transplantation (effectiveness/benefit - utilitarianism), (3) chance for a further donor organ offer (principle of distributive justice: medical urgency - favouring the worst-off), (4) age (medical and social risk factors: sociodemographic status), (5) registered donor (principle of distributive justice: value for society), and (6) individual role in causing organ failure (principle of distributive justice: own fault). Read More

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September 2021

Attack by a common parasitoid stabilizes population dynamics of multi-host communities.

Authors:
Abhyudai Singh

J Theor Biol 2021 Sep 7:110897. Epub 2021 Sep 7.

Department of Electrical and Computer Engineering, Department of Biomedical Engineering, Department of Mathematical Sciences, Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE 19713. Electronic address:

We model the population dynamics of two host species attacked by a common parasitoid using a discrete-time formalism that captures their population densities from year to year. It is well known starting from the seminal work of Nicholson and Bailey that a constant parasitoid attack rate leads to an unstable host-parasitoid interaction. However, a Type III functional response, where the parasitoid attack rate accelerates with increasing host density stabilizes the population dynamics. Read More

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September 2021

Bivariate small area estimation for binary and gaussian variables based on a conditionally specified model.

Biometrics 2021 Sep 10. Epub 2021 Sep 10.

Department of Statistics, Iowa State University, Ames, Iowa, U.S.A.

Many large-scale surveys collect both discrete and continuous variables. Small area estimates may be desired for means of continuous variables, proportions in each level of a categorical variable, or for domain means defined as the mean of the continuous variable for each level of the categorical variable. In this paper, we introduce a conditionally specified bivariate mixed-effects model for small area estimation, and provide a necessary and sufficient condition under which the conditional distributions render a valid joint distribution. Read More

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September 2021