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Mathematical modelling

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https://www.readbyqxmd.com/read/28813938/online-sparse-gaussian-process-based-human-motion-intent-learning-for-an-electrically-actuated-lower-extremity-exoskeleton
#1
Yi Long, Zhi-Jiang Du, Chao-Feng Chen, Wei Dong, Wei-Dong Wang
The most important step for lower extremity exoskeleton is to infer human motion intent (HMI), which contributes to achieve human exoskeleton collaboration. Since the user is in the control loop, the relationship between human robot interaction (HRI) information and HMI is nonlinear and complicated, which is difficult to be modeled by using mathematical approaches. The nonlinear approximation can be learned by using machine learning approaches. Gaussian Process (GP) regression is suitable for high-dimensional and small-sample nonlinear regression problems...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28813895/customized-therapy-using-distributions-of-reaching-errors
#2
Moria F Bittmann, James L Patton, Felix C Huang
While there has been recent success with robotic therapy approaches, individual differences in motor impairments motivate the need for customized therapy. Our latest work with healthy participants considered the likelihood of one's error to construct a customized force field training environment, which we termed an error field. We believe error statistics could characterize individual motor impairments for stroke survivors. Here we present preliminary results from a pilot study testing this therapy technique on individuals following stroke...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
https://www.readbyqxmd.com/read/28813604/experimental-study-and-mathematical-modeling-of-self-sustained-kinetic-oscillations-in-catalytic-oxidation-of-methane-over-nickel
#3
Elena A Lashina, Vasily V Kaichev, Andrey Aleksandrovich Saraev, Zakhar S Vinokurov, Nataliya A Chumakova, Gennadii Chumakov, Valerii I Bukhtiyarov
The self-sustained kinetic oscillations in the oxidation of CH4 over Ni foil have been studied at atmospheric pressure using an X-ray diffraction technique and mass spectrometry. It has been shown that the regular oscillations appear under oxygen-deficient conditions; CO, CO2, H2, and H2O are detected as the products. According to in situ X-ray diffraction measurements nickel periodically oxidizes to NiO initiating the reaction-rate oscillations. To describe the oscillations we have proposed a 5-stage mechanism of the partial oxidation of methane over Ni and a corresponding three-variable kinetic model...
August 16, 2017: Journal of Physical Chemistry. A
https://www.readbyqxmd.com/read/28813427/electromagneto-squeezing-rotational-flow-of-carbon-c-water-h2o-kerosene-oil-nanofluid-past-a-riga-plate-a-numerical-study
#4
Tasawar Hayat, Mumtaz Khan, Muhammad Ijaz Khan, Ahmed Alsaedi, Muhammad Ayub
This article predicts the electromagneto squeezing rotational flow of carbon-water nanofluid between two stretchable Riga plates. Riga plate is known as electromagnetic actuator which is the combination of permanent magnets and a span wise aligned array of alternating electrodes mounted on a plane surface. Mathematical model is developed for the flow problem with the phenomena of melting heat transfer, viscous dissipation and heat generation/absorption. Water and kerosene oil are utilized as the base fluids whereas single and multi-wall carbon nanotubes as the nanomaterials...
2017: PloS One
https://www.readbyqxmd.com/read/28812881/predicting-microbial-fuel-cell-biofilm-communities-and-bioreactor-performance-using-artificial-neural-networks
#5
Keaton Larson Lesnik, Hong Liu
The complex interactions that occur in mixed-species bioelectrochemical reactors, like microbial fuel cells (MFCs), make accurate predictions of performance outcomes under untested conditions difficult. While direct correlations between any individual waste stream characteristic or microbial community structure and reactor performance have not been able to be directly established, the increase in sequencing data and readily available computational power enables the development of alternate approaches. In the current study, 33 MFCs were evaluated under a range of conditions including 8 separate substrates and 3 different wastewaters...
August 16, 2017: Environmental Science & Technology
https://www.readbyqxmd.com/read/28812740/higher-order-interactions-capture-unexplained-complexity-in-diverse-communities
#6
Margaret M Mayfield, Daniel B Stouffer
Natural communities are well known to be maintained by many complex processes. Despite this, the practical aspects of studying them often require some simplification, such as the widespread assumption that direct, additive competition captures the important details about how interactions between species impact community diversity. More complex non-additive 'higher-order' interactions are assumed to be negligible or absent. Notably, these assumptions are poorly supported and have major consequences for the accuracy with which patterns of natural diversity are modelled and explained...
February 17, 2017: Nature ecology & evolution
https://www.readbyqxmd.com/read/28812707/the-rise-and-fall-of-malaria-under-land-use-change-in-frontier-regions
#7
Andres Baeza, Mauricio Santos-Vega, Andrew P Dobson, Mercedes Pascual
Land-use change is the main force behind ecological and social change in many countries around the globe; it is primarily driven by resource needs and external economic incentives. Concomitantly, transformations of the land are the main drivers for the emergence and re-emergence of malaria. An understanding of malaria population dynamics in transforming landscapes is lacking, despite its relevance for developmental and public health policies. We develop a mathematical model that couples malaria epidemiology with the socio-economic and demographic processes that occur in a landscape undergoing land-use change...
March 20, 2017: Nature ecology & evolution
https://www.readbyqxmd.com/read/28812540/quantifying-transmission
#8
Mark Woolhouse
Transmissibility is the defining characteristic of infectious diseases. Quantifying transmission matters for understanding infectious disease epidemiology and designing evidence-based disease control programs. Tracing individual transmission events can be achieved by epidemiological investigation coupled with pathogen typing or genome sequencing. Individual infectiousness can be estimated by measuring pathogen loads, but few studies have directly estimated the ability of infected hosts to transmit to uninfected hosts...
July 2017: Microbiology Spectrum
https://www.readbyqxmd.com/read/28812230/simulation-of-left-ventricular-dynamics-using-a-low-order-mathematical-model
#9
Michael J Moulton, Brian D Hong, Timothy W Secomb
The eventual goal of this study is to develop methods for estimating dynamic stresses in the left ventricle (LV) that could be used on-line in clinical settings, based on routinely available measurements. Toward this goal, a low-order theoretical model is presented, in which LV shape is represented using a small number of parameters, allowing rapid computational simulations of LV dynamics. The LV is represented as a thick-walled prolate spheroid containing helical muscle fibers with nonlinear passive and time-dependent active contractile properties...
August 15, 2017: Cardiovascular Engineering and Technology
https://www.readbyqxmd.com/read/28812023/use-of-a-polyethylene-bag-to-reduce-perioperative-regional-and-whole-body-heat-losses-in-low-birth-weight-neonates
#10
Pierre Tourneux, Estelle Durand, Amandine Pelletier, Laurent Ghyselen, Véronique Bach, Jean-Pierre Libert
In the delivery room, wrapping a low-birth-weight neonate (defined as ≤2.499 g) in a polyethylene bag reduces the risk of hypothermia. However, extended use of the bag (e.g., during neonatal surgery) might conceivably increase the risk of thermal stress and thus body overheating. Here, we assessed the efficacy of a polyethylene bag in infants assigned to wrap (W) or nonwrap (NW, control) groups during placement of a percutaneous vena cava catheter by applying a new mathematical model that calculates heat exchanges for covered and uncovered body segments...
2017: BioMed Research International
https://www.readbyqxmd.com/read/28811996/experimental-method-and-statistical-analysis-to-fit-tumor-growth-model-using-spect-ct-imaging-a-preclinical-study
#11
Ivan Hidrovo, Joyoni Dey, Megan E Chesal, Dmytro Shumilov, Narayan Bhusal, J Michael Mathis
BACKGROUND: Over the last decade, several theoretical tumor-models have been developed to describe tumor growth. Oncology imaging is performed using various modalities including computed tomography (CT), magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT) and fluorodeoxyglucose-positron emission tomography (FDG-PET). Our goal is to extract useful, otherwise hidden, quantitative biophysical parameters (such as growth-rate, tumor-necrotic-factor, etc.) from these serial images of tumors by fitting mathematical models to images...
June 2017: Quantitative Imaging in Medicine and Surgery
https://www.readbyqxmd.com/read/28811214/semi-empirical-modeling-of-microalgae-photosynthesis-in-different-acclimation-states-application-to-n-gaditana
#12
Andrea Bernardi, Andreas Nikolaou, Andrea Meneghesso, Benoît Chachuat, Tomas Morosinotto, Fabrizio Bezzo
The development of mathematical models capable of accurate predictions of the photosynthetic productivity of microalgae under variable light conditions is paramount to the development of large-scale production systems. The process of photoacclimation is particularly important in outdoor cultivation systems, whereby seasonal variation of the light irradiance can greatly influence microalgae growth. This paper presents a dynamic model that captures the effect of photoacclimation on the photosynthetic production...
August 12, 2017: Journal of Biotechnology
https://www.readbyqxmd.com/read/28810960/talk-to-the-hand-u-s-army-biophysical-testing
#13
William R Santee, Adam W Potter, Karl E Friedl
BACKGROUND: Many people are unaware of the science underlying the biophysical properties of Soldier clothing and personal protective equipment, yet there is a well-refined biomedical methodology initiated by Army physiologists in World War II. This involves a methodical progression of systematic material testing technologies, computer modeling, and human testing that enables more efficient development and rapid evaluation of new concepts for Soldier health and performance. Sophisticated manikins that sweat and move are a central part of this testing continuum...
July 2017: Military Medicine
https://www.readbyqxmd.com/read/28809709/a-new-method-for-automatic-sleep-stage-classification
#14
Junming Zhang, Yan Wu
Traditionally, automatic sleep stage classification is quite a challenging task because of the difficulty in translating open-textured standards to mathematical models and the limitations of handcrafted features. In this paper, a new system for automatic sleep stage classification is presented. Compared with existing sleep stage methods, our method can capture the sleep information hidden inside electroencephalography (EEG) signals and automatically extract features from raw data. To translate open sleep stage standards into machine rules recognized by computers, a new model named fast discriminative complex-valued convolutional neural network (FDCCNN) is proposed to extract features from raw EEG data and classify sleep stages...
August 14, 2017: IEEE Transactions on Biomedical Circuits and Systems
https://www.readbyqxmd.com/read/28809676/simultaneous-clustering-and-model-selection-algorithm-theory-and-applications
#15
Zhuwen Li, Loong-Fah Cheong, Shuoguang Yang, Kim-Chuan Toh
While clustering has been well studied in the past decade, model selection has drawn much less attention due to the difficulty of the problem. In this paper, we address both problems in a joint manner by recovering an ideal affinity tensor from an imperfect input. By taking into account the relationship of the affinities induced by the cluster structures, we are able to significantly improve the affinity input, such as repairing those entries corrupted by gross outliers. More importantly, the recovered ideal affinity tensor also directly indicates the number of clusters and their membership, thus solving the model selection and clustering jointly...
August 14, 2017: IEEE Transactions on Pattern Analysis and Machine Intelligence
https://www.readbyqxmd.com/read/28809605/age-modifies-the-effect-of-2-mev-fast-neutrons-on-rat-mammary-carcinogenesis
#16
Tatsuhiko Imaoka, Mayumi Nishimura, Kazuhiro Daino, Ayaka Hosoki, Masaru Takabatake, Toshiaki Kokubo, Kazutaka Doi, Kaye Showler, Yukiko Nishimura, Hitomi Moriyama, Takamitsu Morioka, Yoshiya Shimada, Shizuko Kakinuma
The relative biological effectiveness (RBE) of neutrons depends on their physical nature (e.g., energy) and the biological context (e.g., end points, materials). From the perspective of radiological protection, age is an important biological context that influences radiation-related cancer risk, but very few studies have addressed its potential impact on neutron effects. We therefore investigated the influence of age on the effect of accelerator-generated fast neutrons (mean energy, ∼2 MeV) in an animal model of breast carcinogenesis...
August 15, 2017: Radiation Research
https://www.readbyqxmd.com/read/28809543/infrared-spectroscopy-coupled-with-a-dispersion-model-for-quantifying-the-real-time-dynamics-of-kanamycin-resistance-in-artificial-microbiota
#17
Naifu Jin, Maria Paraskevaidi, Kirk T Semple, Francis Luke Martin, Dayi Zhang
Over-usage of antibiotics leads to the widespread induction of antibiotic resistance genes (ARGs). Developing an approach to allow real-time monitoring and fast prediction of ARGs dynamics in clinical or environmental samples has become an urgent matter. Vibrational spectroscopy is potentially an ideal technique towards the characterization of the microbial composition of microbiota as it is non-destructive, high-throughput and label-free. Herein, we employed attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy and developed a spectrochemical tool to quantify the static and dynamic composition of kanamycin resistance in artificial microbiota to evaluate microbial antibiotic resistance...
August 15, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28808541/how-can-distinct-egg-polymorphism-be-maintained-in-the-rufescent-prinia-prinia-rufescens-plaintive-cuckoo-cacomantis-merulinus-interaction-a-modeling-approach
#18
Wei Liang, Canchao Yang, Fugo Takasu
In avian brood parasitism, both the host and the parasite are expected to develop various conflicting adaptations; hosts develop a defense against parasitism, such as an ability to recognize and reject parasitic eggs that look unlike their own, while parasites evolve egg mimicry to counter this host defense. Hosts may further evolve to generate various egg phenotypes that are not mimicked by parasites. Difference in egg phenotype critically affects the successful reproduction of hosts and parasites. Recent studies have shown that clear polymorphism in egg phenotype is observed in several host-parasite interactions, which suggests that egg polymorphism may be a more universal phenomenon than previously thought...
August 2017: Ecology and Evolution
https://www.readbyqxmd.com/read/28808315/modular-serial-flow-through-device-for-pulsed-electric-field-treatment-of-the-liquid-samples
#19
Maša Kandušer, Aleš Belič, Selma Čorović, Igor Škrjanc
In biotechnology, medicine, and food processing, simple and reliable methods for cell membrane permeabilization are required for drug/gene delivery into the cells or for the inactivation of undesired microorganisms. Pulsed electric field treatment is among the most promising methods enabling both aims. The drawback in current technology is controllable large volume operation. To address this challenge, we have developed an experimental setup for flow through electroporation with online regulation of the flow rate with feedback control...
August 14, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28808008/mathematical-model-reveals-role-of-nucleotide-signaling-in-airway-surface-liquid-homeostasis-and-its-dysregulation-in-cystic-fibrosis
#20
Conner I Sandefur, Richard C Boucher, Timothy C Elston
Mucociliary clearance is composed of three components (i.e., mucin secretion, airway surface hydration, and ciliary-activity) which function coordinately to clear inhaled microbes and other foreign particles from airway surfaces. Airway surface hydration is maintained by water fluxes driven predominantly by active chloride and sodium ion transport. The ion channels that mediate electrogenic ion transport are regulated by extracellular purinergic signals that signal through G protein-coupled receptors. These purinoreceptors and the signaling pathways they activate have been identified as possible therapeutic targets for treating lung disease...
August 14, 2017: Proceedings of the National Academy of Sciences of the United States of America
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