Estrogen Metabolism in the Human. I. Studies in the Male Using Estrone-6,7-3H, with Special Reference to Estrone Production Rate Determinations, the Origin of Certain Urinary Estrogen Conjugates, and the Use of a New Mathematical Model

1967 ◽  
Vol 27 (6) ◽  
pp. 807-818 ◽  
Author(s):  
GORDON C. CROWELL ◽  
MALCOLM E. TURNER ◽  
FREDERICK H. SCHMIDT ◽  
CAROLYN M. HOWARD ◽  
JOHN R. K. PREEDY
Keyword(s):  
Mathematical Model ◽  
Special Reference ◽  
Production Rate ◽  
Estrogen Metabolism

Advanced Mathematical Model for Prediction of Sand Production Rate: A Niger-Delta Case-Study

2020 ◽  
Author(s):  
Ndubuisi Okereke ◽  
Vincent Ogbuka ◽  
Nkemakolam Izuwa ◽  
Fuat Kara ◽  
Ngozi Nwogu ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Production Rate ◽  
Niger Delta ◽  
Sand Production

scholarly journals In vivo regulation of interleukin 1β in patients with cryopyrin-associated periodic syndromes

2009 ◽  
Vol 206 (5) ◽  
pp. 1029-1036 ◽  
Author(s):  
Helen J. Lachmann ◽  
Philip Lowe ◽  
Sandra Daniela Felix ◽  
Christiane Rordorf ◽  
Kieron Leslie ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Clinical Response ◽  
Production Rate ◽  
Healthy Subjects ◽  
Inflammatory Diseases ◽  
Interleukin 1Β ◽  
Complete Clinical Response ◽  
Duration Of Response ◽  
Constitutive Production

The investigation of interleukin 1β (IL-1β) in human inflammatory diseases is hampered by the fact that it is virtually undetectable in human plasma. We demonstrate that by administering the anti–human IL-1β antibody canakinumab (ACZ885) to humans, the resulting formation of IL-1β–antibody complexes allowed the detection of in vivo–produced IL-1β. A two-compartment mathematical model was generated that predicted a constitutive production rate of 6 ng/d IL-1β in healthy subjects. In contrast, patients with cryopyrin-associated periodic syndromes (CAPS), a rare monogenetic disease driven by uncontrolled caspase-1 activity and IL-1 production, produced a mean of 31 ng/d. Treatment with canakinumab not only induced long-lasting complete clinical response but also reduced the production rate of IL-1β to normal levels within 8 wk of treatment, suggesting that IL-1β production in these patients was mainly IL-1β driven. The model further indicated that IL-1β is the only cytokine driving disease severity and duration of response to canakinumab. A correction for natural IL-1 antagonists was not required to fit the data. Together, the study allowed new insights into the production and regulation of IL-1β in man. It also indicated that CAPS is entirely mediated by IL-1β and that canakinumab treatment restores physiological IL-1β production.

A Model of Neuropeptide Transport in Various Types of Nerve Terminals Containing En Passant Boutons: The Effect of the Rate of Neuropeptide Production in the Neuron Soma

2015 ◽  
Author(s):  
I. A. Kuznetsov ◽  
A. V. Kuznetsov
Keyword(s):  
Mathematical Model ◽  
Production Rate ◽  
Retrograde Transport ◽  
Dense Core ◽  
Experimental Results ◽  
Nerve Terminals ◽  
Dense Core Vesicles ◽  
Type Iii ◽  
Neuropeptide Release ◽  
Neuron Soma

After being synthesized in the soma, neuropeptides are packaged in dense core vesicles (DCVs) and transported toward nerve terminals. It is known, from published experimental results, that in terminals with type Ib boutons DCVs circulate in the terminal, undergoing repeated anterograde and retrograde transport, while in type III terminals DCVs do not circulate in the terminal. Our goal here is to investigate whether the increased DCV production in the soma can lead to the appearance of DCV circulation in type III boutons. For this purpose we developed a mathematical model that simulates DCV transport in various terminals. Our model reproduces some important experimental results, such as those concerning DCV circulation in type Ib and type III terminals. We used the developed model to make testable predictions. The model predicts that an increased DCV production rate in the soma leads to increased DCV circulation in type Ib boutons and to the appearance of DCV circulation in type III boutons. The model also predicts that there are different stages in the development of DCV circulation in the terminals after they were depleted of DCVs due to neuropeptide release.

Modeling Transition in Separated and Attached Boundary Layers

2004 ◽  
Vol 127 (2) ◽  
pp. 402-411 ◽  
Author(s):  
Stephen K. Roberts ◽  
Metin I. Yaras
Keyword(s):  
Boundary Layer ◽  
Mathematical Model ◽  
Surface Roughness ◽  
Production Rate ◽  
Transition Zone ◽  
Boundary Layers ◽  
Shape Factor ◽  
Separated Flow ◽  
Flow Transition ◽  
Turbulent Spot

This paper presents a mathematical model for predicting the rate of turbulent spot production. In this model, attached- and separated-flow transition are treated in a unified manner, and the boundary layer shape factor is identified as the parameter with which the spot production rate correlates. The model is supplemented by several correlations to allow for its practical use in the prediction of the length of the transition zone. Second, the paper presents a model for the prediction of the location of transition inception in separation bubbles. The model improves on the accuracy of existing alternatives, and is the first to account for the effects of surface roughness.

Coupling between phosphate and calcium homeostasis: a mathematical model

2017 ◽  
Vol 313 (6) ◽  
pp. F1181-F1199 ◽  
Author(s):  
David Granjon ◽  
Olivier Bonny ◽  
Aurélie Edwards
Keyword(s):  
Mathematical Model ◽  
Vitamin D ◽  
Parathyroid Hormone ◽  
Production Rate ◽  
Fibroblast Growth Factor 23 ◽  
Feedback Loops ◽  
Fibroblast Growth ◽  
Small Perturbations ◽  
Intracellular Pool ◽  
Negative Feedback Loops

We developed a mathematical model of calcium (Ca) and phosphate (PO4) homeostasis in the rat to elucidate the hormonal mechanisms that underlie the regulation of Ca and PO4balance. The model represents the exchanges of Ca and PO4between the intestine, plasma, kidneys, bone, and the intracellular compartment, and the formation of Ca-PO4-fetuin-A complexes. It accounts for the regulation of these fluxes by parathyroid hormone (PTH), vitamin D3, fibroblast growth factor 23, and Ca2+-sensing receptors. Our results suggest that the Ca and PO4homeostatic systems are robust enough to handle small perturbations in the production rate of either PTH or vitamin D3. The model predicts that large perturbations in PTH or vitamin D3synthesis have a greater impact on the plasma concentration of Ca2+([Ca2+]p) than on that of PO4([PO4]p); due to negative feedback loops, [PO4]pdoes not consistently increase when the production rate of PTH or vitamin D3is decreased. Our results also suggest that, following a large PO4infusion, the rapidly exchangeable pool in bone acts as a fast, transient storage PO4compartment (on the order of minutes), whereas the intracellular pool is able to store greater amounts of PO4over several hours. Moreover, a large PO4infusion rapidly lowers [Ca2+]powing to the formation of CaPO4complexes. A large Ca infusion, however, has a small impact on [PO4]p, since a significant fraction of Ca binds to albumin. This mathematical model is the first to include all major regulatory factors of Ca and PO4homeostasis.

scholarly journals Mathematical model shows how sleep may affect amyloid β fibrillization

2019 ◽  
Author(s):  
Masoud Hoore ◽  
Sahamoddin Khailaie ◽  
Ghazal Montaseri ◽  
Tanmay Mitra ◽  
Michael Meyer-Hermann
Keyword(s):  
Mathematical Model ◽  
Production Rate ◽  
Amyloid Β ◽  
Cellular Level ◽  
Long Time ◽  
Diseased State ◽  
Aβ Fibers ◽  
The Impact ◽  
The Brain ◽  
Good Sleep

AbstractDeposition of amyloid β (Aβ) fibers in extra-cellular matrix of the brain is a ubiquitous feature associated with several neurodegenerative disorders, especially Alzheimer’s disease (AD). While many of the biological aspects that contribute to the formation of Aβ plaques are well addressed at the intra- and inter-cellular level in short timescales, an understanding of how Aβ fibrillization usually starts to dominate at a longer timescale in spite of the presence of mechanisms dedicated to Aβ clearance, is still lacking. Furthermore, no existing mathematical model integrates the impact of diurnal neural activity as emanated from circadian regulation to predict disease progression due to a disruption in sleep-wake cycle. In this study, we develop a minimal model of Aβ fibrillization to investigate the onset of AD over a long time-scale. Our results suggest that the diseased state is a manifestation of a phase change of the system from soluble Aβ (sAβ) to fibrillar Aβ (fAβ) domination upon surpassing a threshold in the production rate of soluble Aβ. By incorporating the circadian rhythm into our model, we reveal that fAβ accumulation is crucially dependent on the regulation of sleep-wake cycle, thereby indicating the importance of a good sleep hygiene in averting AD onset. We also discuss potential intervention schemes to reduce fAβ accumulation in the brain by modification of the critical sAβ production rate.

scholarly journals An Automated Smart EPQ-Based Inventory Model for Technology-Dependent Products under Stochastic Failure and Repair Rate

Symmetry ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 388 ◽  
Author(s):  
Iqra Asghar ◽  
Jong Soo Kim
Keyword(s):  
Mathematical Model ◽  
Production Rate ◽  
Production Efficiency ◽  
Manufacturing System ◽  
Manufacturing Technology ◽  
Repair Time ◽  
High Tech ◽  
Performance Quality ◽  
Maintenance Model ◽  
Variable Production

With the ever-growing technology development, high-tech products such as mobile phones, computers, electromagnetic devices and smart devices are facing high design and production modification requirements with relatively shorter life cycles. For instance, every forthcoming smart phone goes out of production in a shorter period after its launch, followed by its next generation. The design of high-tech products requires high investments in smart and automated manufacturing technology to ensure higher production efficiency. For high-tech products with short life spans, the manufacturing performance-quality variable is an important design parameter that affects system reliability, production efficiency and manufacturing costs. Major performance-quality factors of a manufacturing system which affect productivity and reliability of the manufacturing process are discussed in this research. The study investigates an integrated smart production maintenance model under stochastic manufacturing reliability for technology dependent demand and variable production rate. The smart unit production cost is a function of manufacturing reliability and controllable production rate, as a manufacturing system can be operated at different production rates within designed limits μ ϵ [ μ m i n , μ m a x ] . Manufacturing reliability is increased through investment in smart manufacturing technology and resources. The integrated smart production maintenance model is formulated under general failure and repair time distributions and the optimal production maintenance policy is investigated under specific failure and repair time distributions. A mathematical model is developed to optimize the manufacturing quality-performance parameter, variable production rate, per unit technology investment and production lot size. The total cost function is optimized through the Khun–Tucker method. The mathematical model is also validated with numerical analysis, comparative study, and sensitivity analysis for model key parameters.

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