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https://www.readbyqxmd.com/read/28324962/design-of-a-dual-hormone-model-predictive-control-for-artificial-pancreas-with-exercise-model
#1
Navid Resalat, Joseph El Youssef, Ravi Reddy, Peter G Jacobs
The Artificial Pancreas (AP) is a new technology for helping people with type 1 diabetes to better control their glucose levels through automated delivery of insulin and optionally glucagon in response to sensed glucose levels. In a dual hormone AP, insulin and glucagon are delivered automatically to the body based on glucose sensor measurements using a control algorithm that calculates the amount of hormones to be infused. A dual-hormone MPC may deliver insulin continuously; however, it must avoid continuous delivery of glucagon because nausea can occur from too much glucagon...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28324937/data-driven-estimation-of-blood-pressure-using-photoplethysmographic-signals
#2
Shi Chao Gao, Peter Wittek, Li Zhao, Wen Jun Jiang
Noninvasive measurement of blood pressure by optical methods receives considerable interest, but the complexity of the measurement and the difficulty of adjusting parameters restrict applications. We develop a method for estimating the systolic and diastolic blood pressure using a single-point optical recording of a photoplethysmographic (PPG) signal. The estimation is data-driven, we use automated machine learning algorithms instead of mathematical models. Combining supervised learning with a discrete wavelet transform, the method is insensitive to minor irregularities in the PPG waveform, hence both pulse oximeters and smartphone cameras can record the signal...
August 2016: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
https://www.readbyqxmd.com/read/28319762/growth-of-algal-biomass-in-laboratory-and-in-large-scale-algal-photobioreactors-in-the-temperate-climate-of-western-germany
#3
Christina Schreiber, Dominik Behrendt, Gregor Huber, Christian Pfaff, Janka Widzgowski, Bärbel Ackermann, Andreas Müller, Vilém Zachleder, Šárka Moudříková, Peter Mojzeš, Ulrich Schurr, Johan Grobbelaar, Ladislav Nedbal
Growth of Chlorella vulgaris was characterized as a function of irradiance in a laboratory turbidostat (1L) and compared to batch growth in sunlit modules (5-25L) of the commercial NOVAgreen photobioreactor. The effects of variable sunlight and culture density were deconvoluted by a mathematical model. The analysis showed that algal growth was light-limited due to shading by external construction elements and due to light attenuation within the algal bags. The model was also used to predict maximum biomass productivity...
March 7, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28318629/machine-learning-algorithms-define-pathogen-specific-local-immune-fingerprints-in-peritoneal-dialysis-patients-with-bacterial-infections
#4
Jingjing Zhang, Ida M Friberg, Ann Kift-Morgan, Gita Parekh, Matt P Morgan, Anna Rita Liuzzi, Chan-Yu Lin, Kieron L Donovan, Chantal S Colmont, Peter H Morgan, Paul Davis, Ian Weeks, Donald J Fraser, Nicholas Topley, Matthias Eberl
The immune system has evolved to sense invading pathogens, control infection, and restore tissue integrity. Despite symptomatic variability in patients, unequivocal evidence that an individual's immune system distinguishes between different organisms and mounts an appropriate response is lacking. We here used a systematic approach to characterize responses to microbiologically well-defined infection in a total of 83 peritoneal dialysis patients on the day of presentation with acute peritonitis. A broad range of cellular and soluble parameters was determined in peritoneal effluents, covering the majority of local immune cells, inflammatory and regulatory cytokines and chemokines as well as tissue damage-related factors...
March 16, 2017: Kidney International
https://www.readbyqxmd.com/read/28318565/the-counterintuitive-role-of-extra-column-volume-in-the-determination-of-column-efficiency-and-scaling-of-chromatographic-processes
#5
A Schultze-Jena, M A Boon, P J Th Bussmann, A E M Janssen, A van der Padt
In industrial liquid separation processes chromatography often has a key function in the optimization of yield and purity. For the design of an industrial system, chromatographic processes are generally simulated using mathematical models, tested and optimized at laboratory level, and then scaled up to pilot and subsequently industrial scale. To describe the system, experimental data and model data need to be fitted and extra column contribution must be determined. This paper describes the influence of extra-column volume on overall separation efficiency for lab scale and its impact on the design of large scale systems...
March 1, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28318033/changes-in-the-chloroplastic-co2-concentration-explain-much-of-the-observed-kok-effect-a-model
#6
Graham D Farquhar, Florian A Busch
Mitochondrial respiration often appears to be inhibited in the light when compared with measurements in the dark. This inhibition is inferred from the response of the net CO2 assimilation rate (A) to absorbed irradiance (I), changing slope around the light compensation point (Ic ). We suggest a model that provides a plausible mechanistic explanation of this 'Kok effect'. The model uses the mathematical description of photosynthesis developed by Farquhar, von Caemmerer and Berry; it involves no inhibition of respiration rate in the light...
April 2017: New Phytologist
https://www.readbyqxmd.com/read/28317944/inferring-biomarkers-for-mycobacterium-avium-subsp-paratuberculosis-infection-and-disease-progression-in-cattle-using-experimental-data
#7
Gesham Magombedze, Tinevimbo Shiri, Shigetoshi Eda, Judy R Stabel
Available diagnostic assays for Mycobacterium avium subsp. paratuberculosis (MAP) have poor sensitivities and cannot detect early stages of infection, therefore, there is need to find new diagnostic markers for early infection detection and disease stages. We analyzed longitudinal IFN-γ, ELISA-antibody and fecal shedding experimental sensitivity scores for MAP infection detection and disease progression. We used both statistical methods and dynamic mathematical models to (i) evaluate the empirical assays (ii) infer and explain biological mechanisms that affect the time evolution of the biomarkers, and (iii) predict disease stages of 57 animals that were naturally infected with MAP...
March 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28317845/dna-damage-during-s-phase-mediates-the-proliferation-quiescence-decision-in-the-subsequent-g1-via-p21-expression
#8
Alexis R Barr, Samuel Cooper, Frank S Heldt, Francesca Butera, Henriette Stoy, Jörg Mansfeld, Béla Novák, Chris Bakal
Following DNA damage caused by exogenous sources, such as ionizing radiation, the tumour suppressor p53 mediates cell cycle arrest via expression of the CDK inhibitor, p21. However, the role of p21 in maintaining genomic stability in the absence of exogenous DNA-damaging agents is unclear. Here, using live single-cell measurements of p21 protein in proliferating cultures, we show that naturally occurring DNA damage incurred over S-phase causes p53-dependent accumulation of p21 during mother G2- and daughter G1-phases...
March 20, 2017: Nature Communications
https://www.readbyqxmd.com/read/28316340/pitowsky-s-kolmogorovian-models-and-super-determinism
#9
Jakob Kellner
In an attempt to demonstrate that local hidden variables are mathematically possible, Pitowsky constructed "spin-[Formula: see text] functions" and later "Kolmogorovian models", which employs a nonstandard notion of probability. We describe Pitowsky's analysis and argue (with the benefit of hindsight) that his notion of hidden variables is in fact just super-determinism (and accordingly physically not relevant). Pitowsky's first construction uses the Continuum Hypothesis. Farah and Magidor took this as an indication that at some stage physics might give arguments for or against adopting specific new axioms of set theory...
2017: Foundations of Physics
https://www.readbyqxmd.com/read/28316111/pattern-separation-in-the-hippocampus-through-the-eyes-of-computational-modeling
#10
REVIEW
Spyridon Chavlis, Panayiota Poirazi
Pattern separation is a mnemonic process that has been extensively studied over the years. It entails the ability -of primarily hippocampal circuits- to distinguish between highly similar inputs, via generating different neuronal activity (output) patterns. The dentate gyrus in particular has long been hypothesized to implement pattern separation by detecting and storing similar inputs as distinct representations. The ways in which these distinct representations can be generated have been explored in a number of theoretical and computational modelling studies...
March 18, 2017: Synapse
https://www.readbyqxmd.com/read/28315690/prediction-of-human-pharmacokinetic-profile-after-transdermal-drug-application-using-excised-human-skin
#11
Syunsuke Yamamoto, Masatoshi Karashima, Yuta Arai, Kimio Tohyama, Nobuyuki Amano
Although several mathematical models have been reported for the estimation of human plasma concentration profiles of drug substances after dermal application, the successful cases that can predict human pharmacokinetic profiles are limited. Therefore, the aim of this study was to investigate the prediction of human plasma concentrations after dermal application using in vitro permeation parameters obtained from excised human skin. The in vitro skin permeability of seven marketed drug products was evaluated...
March 15, 2017: Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28315616/counterfactual-simulations-applied-to-shrp2-crashes-the-effect-of-driver-behavior-models-on-safety-benefit-estimations-of-intelligent-safety-systems
#12
Jonas Bärgman, Christian-Nils Boda, Marco Dozza
As the development and deployment of in-vehicle intelligent safety systems (ISS) for crash avoidance and mitigation have rapidly increased in the last decades, the need to evaluate their prospective safety benefits before introduction has never been higher. Counterfactual simulations using relevant mathematical models (for vehicle dynamics, sensors, the environment, ISS algorithms, and models of driver behavior) have been identified as having high potential. However, although most of these models are relatively mature, models of driver behavior in the critical seconds before a crash are still relatively immature...
March 15, 2017: Accident; Analysis and Prevention
https://www.readbyqxmd.com/read/28306750/optimal-pricing-and-marketing-planning-for-deteriorating-items
#13
Seyed Reza Moosavi Tabatabaei, Seyed Jafar Sadjadi, Ahmad Makui
Optimal pricing and marketing planning plays an essential role in production decisions on deteriorating items. This paper presents a mathematical model for a three-level supply chain, which includes one producer, one distributor and one retailer. The proposed study considers the production of a deteriorating item where demand is influenced by price, marketing expenditure, quality of product and after-sales service expenditures. The proposed model is formulated as a geometric programming with 5 degrees of difficulty and the problem is solved using the recent advances in optimization techniques...
2017: PloS One
https://www.readbyqxmd.com/read/28303791/integer-programming-based-method-for-observability-of-singleton-attractors-in-boolean-networks
#14
Xiaoqing Cheng, Yushan Qiu, Wenpin Hou, Wai-Ki Ching
Boolean network (BN) is a popular mathematical model for revealing the behaviour of a genetic regulatory network. Furthermore, observability, an important network feature, plays a significant role in understanding the underlying network. Several studies have been done on analysis of observability of BNs and complex networks. However, the observability of attractor cycles, which can serve as biomarker detection, has not yet been addressed in the literature. This is an important, interesting and challenging problem that deserves a detailed study...
February 2017: IET Systems Biology
https://www.readbyqxmd.com/read/28303745/grid-therapy-using-high-definition-multileaf-collimators-realizing-benefits-of-the-bystander-effect
#15
Valery Peng, Natalka Suchowerska, Linda Rogers, Elizabeth Claridge Mackonis, Samantha Oakes, David R McKenzie
BACKGROUND: In microbeam radiotherapy (MRT), parallel arrays of high-intensity synchrotron x-ray beams achieve normal tissue sparing without compromising tumor control. Grid-therapy using clinical linacs has spatial modulation on a larger scale and achieves promising results for palliative treatments of bulky tumors. The availability of high definition multileaf collimators (HDMLCs) with 2.5 mm leaves provides an opportunity for grid-therapy to more closely approach MRT. However, challenges to the wider implementation of grid-therapy remain because spatial modulation of the target volume runs counter to current radiotherapy practice and mechanisms for the beneficial effects of MRT are not fully understood...
March 17, 2017: Acta Oncologica
https://www.readbyqxmd.com/read/28303275/modeling-pathological-hemodynamic-responses-to-the-valsalva-maneuver
#16
Leszek Pstras, Karl Thomaseth, Jacek Waniewski, Italo Balzani, Federico Bellavere
The Valsalva maneuver consisting in a forced expiration against closed airways is one of the most popular clinical tests of the autonomic nervous system function. When properly performed by a healthy subject, it features four characteristic phases of arterial blood pressure and heart rate variations, based on the magnitude of which the autonomic function may be assessed qualitatively and quantitatively. In patients with some disorders or in healthy patients subject to specific conditions, the pattern of blood pressure and heart rate changes during the execution of the Valsalva maneuver may, however, differ from the typical sinusoidal-like pattern...
March 17, 2017: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/28303274/design-of-a-wireless-medical-capsule-for-measuring-the-contact-pressure-between-a-capsule-and-the-small-intestine
#17
Pengbo Li, Craig Kreikemeier-Bower, Wanchuan Xie, Vishal Kothari, Benjamin S Terry
A wireless medical capsule for measuring the contact pressure between a mobile capsule and the small intestine lumen was developed. Two pressure sensors were used to measure and differentiate the contact pressure and the small intestine intraluminal pressure. After in vitro tests of the capsule, it was surgically placed and tested in the proximal small intestine of a pig model. The capsule successfully gathered and transmitted the pressure data to an ex vivo receiver. The measured pressure signals in the animal test were analyzed in the time and frequency domains and a mathematic model was presented to describe the different factors influencing the contact pressure...
March 17, 2017: Journal of Biomechanical Engineering
https://www.readbyqxmd.com/read/28303104/mathematical-modeling-of-streptococcus-pneumoniae-colonization-invasive-infection-and-treatment
#18
Elisa Domínguez-Hüttinger, Neville J Boon, Thomas B Clarke, Reiko J Tanaka
Streptococcus pneumoniae (Sp) is a commensal bacterium that normally resides on the upper airway epithelium without causing infection. However, factors such as co-infection with influenza virus can impair the complex Sp-host interactions and the subsequent development of many life-threatening infectious and inflammatory diseases, including pneumonia, meningitis or even sepsis. With the increased threat of Sp infection due to the emergence of new antibiotic resistant Sp strains, there is an urgent need for better treatment strategies that effectively prevent progression of disease triggered by Sp infection, minimizing the use of antibiotics...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28302869/motor-and-mechanical-bases-of-the-courtship-call-of-the-male-treehopper-umbonia-crassicornis
#19
Carol I Miles, Brianna E Allison, Michael J Losinger, Quang T Su, Ronald N Miles
This study is a physiological, anatomical, and biophysical analysis of how plant-borne vibrational signals are produced by the treehopper Umbonia crassicornis During courtship, males and females engage in a vibrational duet, with each producing a characteristic call. For males, this consists of a frequency-modulated tonal signal which is accompanied by rhythmic broad-band clicks. While previous studies described these complex signals in detail, little is known about how they are produced. By combining video recordings, electromyograms, dissections and mechanical modelling, we describe the mechanism by which the male produces his courtship signal...
March 16, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28302144/a-dosimetric-model-for-the-heterogeneous-delivery-of-radioactive-nanoparticles-in-vivo-a-feasibility-study
#20
Andrew B Satterlee, Peter Attayek, Bentley Midkiff, Leaf Huang
ᅟ: Accurate and quantitative dosimetry for internal radiation therapy can be especially challenging, given the heterogeneity of patient anatomy, tumor anatomy, and source deposition. Internal radiotherapy sources such as nanoparticles and monoclonal antibodies require high resolution imaging to accurately model the heterogeneous distribution of these sources in the tumor. The resolution of nuclear imaging modalities is not high enough to measure the heterogeneity of intratumoral nanoparticle deposition or intratumoral regions, and mathematical models do not represent the actual heterogeneous dose or dose response...
March 17, 2017: Radiation Oncology
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