scholarly journals Multistage feedback driven compartmental dynamics of hematopoiesis

2020 ◽  
Author(s):  
Nathaniel V. Mon Père ◽  
Tom Lenaerts ◽  
Jorge M. Pacheco ◽  
David Dingli
Keyword(s):  
Severe Bleeding ◽  
Bone Marrow Transplants ◽  
Stable States ◽  
Blood Disorders ◽  
Cell Dynamics ◽  
Different Types ◽  
Maturation Stages ◽  
Hierarchical Nature ◽  
Feedback Networks ◽  
Compartment Cell

AbstractHuman hematopoiesis is surprisingly resilient to disruptions, providing suitable responses to severe bleeding, long lasting immune activation, and even bone marrow transplants. Still, many blood disorders exist which push the system past its natural plasticity, resulting in abnormalities in the circulating blood. While proper treatment of such diseases can benefit from understanding the underlying cell dynamics, these are non-trivial to predict due to the hematopoietic system’s hierarchical nature and complex feedback networks. To characterize the dynamics following different types of perturbations we investigate a model representing hematopoiesis as a sequence of compartments covering all maturation stages – from stem to mature cells – where feedback regulates cell production to ongoing necessities. We find that a stable response to perturbations requires the simultaneous adaptation of cell differentiation and self-renewal rates, and show that under conditions of continuous disruption – as found in chronic hemolytic states – compartment cell numbers evolve to novel stable states.

scholarly journals Dynamics and Stability of Constitutions, Coalitions, and Clubs

2012 ◽  
Vol 102 (4) ◽  
pp. 1446-1476 ◽  
Author(s):  
Daron Acemoglu ◽  
Georgy Egorov ◽  
Konstantin Sonin
Keyword(s):  
Decision Making ◽  
General Framework ◽  
Political Power ◽  
Collective Decision ◽  
Collective Decision Making ◽  
Political Rights ◽  
Stable States ◽  
Initial State ◽  
Social Arrangement ◽  
Different Types

In dynamic collective decision making, current decisions determine the future distribution of political power and influence future decisions. We develop a general framework to study this class of problems. Under acyclicity, we characterize dynamically stable states as functions of the initial state and obtain two general insights. First, a social arrangement is made stable by the instability of alternative arrangements that are preferred by sufficiently powerful groups. Second, efficiency-enhancing changes may be resisted because of further changes they will engender. We use this framework to analyze dynamics of political rights in a society with different types of extremist views. (JEL D71, D72, K10)

Global Masculinities, Femininities, and Sexualities

2012 ◽  
Author(s):  
Celeste Montoya ◽  
Sarah McCullar ◽  
Marjon Kamrani
Keyword(s):  
International Relations ◽  
Sexual Identity ◽  
Subject Matter ◽  
Power Dynamics ◽  
Multiple Forms ◽  
Postcolonial Feminism ◽  
Feminist Standpoint ◽  
The Feminine ◽  
Different Types ◽  
Hierarchical Nature

Feminist international relations (IR) scholars have worked to expand understandings of the global processes through studies of gender. There are multiple forms of feminist scholars and scholarship, with each epistemology having its own understanding of gender and its role in influencing international relations. These include feminist empiricism, feminist standpoint, poststructuralist feminist approaches, and postcolonial feminism. Some of the early feminist IR scholarship placed most of their emphasis on critiquing patriarchy, sometimes resulting to a narrow and essentialist construction of masculinity. These early works note the absence of women and the denigration of the feminine, as well as the predominance of masculine subject matter and masculine partiality in IR. This began to change with the recognition of different types of masculinities, offering a broader conceptualization of gender and masculinities beyond attachment to sex. Beyond recognizing the relational differences between masculinity and femininity, feminist scholars have also pointed out the differential value accorded to each, thus emphasizing the problematic hierarchical nature of such binaries. Another goal of feminist scholars has been to uncover the feminine roles rendered invisible, to challenge the masculine nature of IR as a discipline as well as deal with descriptive and substantive representational issues within the field and practice of IR. Meanwhile, the study of sexualities focuses on power dynamics and the hierarchies associated with sexual identity in its many forms. The predominant themes in this study include sexuality in relation to the study of war and nation; sexuality as a commodity; and studies of hetero- and homonormativity.

scholarly journals Nonlinear current-voltage relationships in cultured macrophages.

1980 ◽  
Vol 85 (1) ◽  
pp. 160-165 ◽  
Author(s):  
E K Gallin ◽  
D R Livengood
Keyword(s):  
High Resistance ◽  
Membrane Potentials ◽  
Transitional Region ◽  
Stable States ◽  
Excitable Cells ◽  
Electrophysiological Properties ◽  
Current Pulses ◽  
Current Voltage ◽  
Different Types ◽  
Peritoneal Exudate Macrophages

Intracellular recordings of cultured mouse thioglycolate-induced peritoneal exudate macrophages reveal that these cells can exhibit two different types of electrophysiological properties characterized by differences in their current-voltage relationships and their resting membrane potentials. The majority of cells had low resting membrane potentials (-20 to -40 mV) and displayed current-voltage relationships that were linear for inward-going current pulses and rectifying for outward-going pulses. Small depolarizing transients, occurring either spontaneously or induced by current pulses, were seen in some cells with low resting membrane potentials. A second smaller group of cells exhibited more hyperpolarized resting membrane potentials (-60 to -90 mV) and S-shaped current-voltage relationships associated with a high-resistance transitional region. Cells with S-shaped current-voltage relationships sometimes exhibited two stable states of membrane potential on either side of the high-resistance transitional region. These data indicate that macrophages exhibit complex electrophysiological properties often associated with excitable cells.

scholarly journals Transitions in synchronization states of model cilia through basal-connection coupling

2018 ◽  
Vol 15 (147) ◽  
pp. 20180450 ◽  
Author(s):  
Yujie Liu ◽  
Rory Claydon ◽  
Marco Polin ◽  
Douglas R. Brumley
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Basal Body ◽  
Minimal Model ◽  
Phase Synchronization ◽  
Eukaryotic Cells ◽  
Mechanical State ◽  
Stable States ◽  
Mechanical Coupling ◽  
Different Types

Despite evidence for a hydrodynamic origin of flagellar synchronization between different eukaryotic cells, recent experiments have shown that in single multi-flagellated organisms, coordination hinges instead on direct basal body connections. The mechanism by which these connections lead to coordination, however, is currently not understood. Here, we focus on the model biflagellate Chlamydomonas reinhardtii , and propose a minimal model for the synchronization of its two flagella as a result of both hydrodynamic and direct mechanical coupling. A spectrum of different types of coordination can be selected, depending on small changes in the stiffness of intracellular couplings. These include prolonged in-phase and anti-phase synchronization, as well as a range of multi-stable states induced by spontaneous symmetry breaking of the system. Linking synchrony to intracellular stiffness could lead to the use of flagellar dynamics as a probe for the mechanical state of the cell.

scholarly journals Self-Organizing Processes in Landscape Pattern and Resilience: A Review

ISRN Ecology ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-18 ◽  
Author(s):  
Donald L. DeAngelis
Keyword(s):  
Large Scale ◽  
Alternative Stable States ◽  
Bare Soil ◽  
Landscape Patterns ◽  
Vegetation Patterns ◽  
Vegetation Types ◽  
Stable States ◽  
Common Basis ◽  
Different Types ◽  
Halophytic Plants

Environmental conditions influence the way different types of vegetation are distributed on various scales from the landscape to the globe. However, vegetation does not simply respond passively but may influence its environment in ways that shape those distributions. On the landscape scale, feedbacks from vegetation can lead to patterns that are not easily interpreted as merely reflecting external abiotic conditions. For example, sharp ecotones exist between two vegetation types, even if the basic abiotic gradient is slight, somewhere along the gradient. These are observed in transitions between numerous pairs of ecosystem types, such as tree/grassland, tree/mire, tree tundra, and halophytic plants/glycophytic plants. More complex spatial vegetation patterns may also exist, such as alternating stripes or irregular patterns of either two types of vegetation or vegetation and bare soil. One purpose of this paper is to emphasize that these two types of patterns, sharp ecotones between vegetation types and large-scale landscape patterns of vegetation, both have a common basis in the concept of bistability, in which alternative stable states can occur on an area of land. Another purpose is to note that an understanding of the basis of these patterns may ultimately help in management decisions.

Bioimage: Towards a New Data Base of Biological Volumes

1997 ◽  
Vol 3 (S2) ◽  
pp. 1133-1134
Author(s):  
Carazo José María
Keyword(s):  
Data Base ◽  
Scientific Knowledge ◽  
Cell Biology ◽  
The Other ◽  
Current Work ◽  
Macromolecular Structure ◽  
Cell Dynamics ◽  
Internal Organization ◽  
Different Types

This presentation introduces the current work of the Bioimage Corsortium and its international collaborators in the setting up of a new data base containing volumes of biological specimens.The scope of the data that we will be organizing during the next three years is very broad, ranging from macromolecules to larger structures or even entire cells. The approach is designed to combine the desire to break many undesired formal barriers between the type of volume information produced at the different resolution levels whith, at the same time, the clear need of implementational flexibility required to appropriately handle different types of data.The internal organization of the Bioimage Consortium clearly reflects the objectives presented above. In the first place, partners in the consortium have the scientific knowledge and projection in areas ranging from macromolecular structure to cell dynamics. These partners are then nucleated around two well-defined “servers”, one in Madrid, responsible for the work on macromolecular structures, and the other in Heildeberg, responsible for data more in the area of cell biology.

scholarly journals Hemorrhage Risk of Patients Receiving Bronchoscope Examination or Treatment

2020 ◽  
Author(s):  
Liyan Bo ◽  
Yanyan Li ◽  
Faguang Jin ◽  
Congcong Li
Keyword(s):  
Complication Rate ◽  
General Information ◽  
Severe Bleeding ◽  
Common Complication ◽  
Bleeding Rate ◽  
Different Types ◽  
Hemorrhage Risk

Abstract Background: The type of procedures has changed and become more complex and sophisticated with the development and extensive use of bronchoscopy. This study aimed to evaluate the safety, particularly the hemorrhage risk, of patients receiving bronchoscope examination or treatment.Methods: The general information and bronchoscope procedures of patients who underwent bronchoscope examination or treatment in the respiration department were collected and analyzed.Results: The incidence of complications and the mortality in bronchoscopy were 0.85% and 0.01%, respectively. The complication rate of different types of bronchoscope procedure varies significantly, and that of therapeutic bronchoscopies was higher than that of explorative examinations and biopsies. Moreover, the most common complication was severe bleeding. Bleeding rate was higher in the left upper lobe and bronchus intermedius, and a trend was observed in which the proportion of bleeding cases decreased as the number of biopsies increased.Conclusions: Although bronchoscope procedure has become more complex and sophisticated, bronchoscopy is well tolerated. However, precautions should be taken because the risks of hemorrhage and pneumothorax were high and fatal.

Web Platform to Support the Portuguese National Registry of Haemophilia and Other Inherited Blood Disorders

2015 ◽  
Vol 7 (1) ◽  
pp. 65-80 ◽  
Author(s):  
Leonor Teixeira ◽  
Vasco Saavedra ◽  
Carlos Ferreira ◽  
Beatriz Sousa Santos
Keyword(s):  
National Registry ◽  
Special Role ◽  
Blood Disorders ◽  
Patient Registries ◽  
Web Based ◽  
Data Centre ◽  
Different Types ◽  
The University ◽  
Web Platform ◽  
Epidemiological Information

Patient registries are essential tools for identifying and tracking people with a particular disease and for collecting epidemiological information, having a special role in rare and chronic diseases, where haemophilia and other inherited blood disorders (HoIBD) are classified. Web-based technologies represent an excellent solution to support different types of registries, due to the benefits that they can promote in the management of disease data. This work presents the web platform developed in a joint initiative between the Portuguese Association of Congenital Coagulopathies (PACC) and the University of Aveiro (UA), with the purpose of creating the first National Patients Registry (NPR) with HoIBD in Portugal. This application is hosted in the data centre of the UA, and at this moment it is already used by clinicians of the different Haemophilia Treatment Centres (HTC) located in Portugal, with the next challenge being the increase in the number of users.

scholarly journals ANKRD26-related thrombocytopenia: case report and literature review of inherited thrombocytopenias with predisposition to malignancies

2019 ◽  
Vol 18 (3) ◽  
pp. 54-61
Author(s):  
Ya. A. Erdomaeva ◽  
D. V. Fedorova ◽  
P. A. Zharkov ◽  
M. A. Kurnikova ◽  
S. G. Mann ◽  
...  
Keyword(s):  
Myeloid Leukemia ◽  
Clinical Case ◽  
Personal Data ◽  
Severe Bleeding ◽  
Blood Disorders ◽  
Rare Form ◽  
Long Term Follow Up ◽  
Paper Review

ANKRD26-related thrombocytopenia (previously known as thrombocytopenia-2) is a rare form of inherited platelet disorders. Patients with ANKRD26-related thrombocytopenia usually do not suffer from severe bleeding but have predisposition to acute myeloid leukemia and other malignancies. Patients with ANKRD26-related thrombocytopenia and their relatives need genetic consultation and long term follow-up in view of risk of malignant blood disorders. The clinical case of ANKRD26-related thrombocytopenia in two siblings is presented in this paper. Review of literary data on pathogenesis, treatment and follow-up of patients with ANKRD26-related thrombocytopenia is performed. Common questions of diagnosis and management in patients with congenital thrombocytopenias with predisposition to malignant blood disorders are also reviewed. Parents gave their permission for using personal data for clinical research and publications.

The extinction time of a general birth and death process with catastrophes

1986 ◽  
Vol 23 (04) ◽  
pp. 851-858 ◽  
Author(s):  
P. J. Brockwell
Keyword(s):  
Laplace Transform ◽  
Size Distribution ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Death Process ◽  
Extinction Time ◽  
Birth And Death Process ◽  
Different Types ◽  
The Laplace Transform ◽  
Necessary And Sufficient

The Laplace transform of the extinction time is determined for a general birth and death process with arbitrary catastrophe rate and catastrophe size distribution. It is assumed only that the birth rates satisfyλ0= 0,λj> 0 for eachj> 0, and. Necessary and sufficient conditions for certain extinction of the population are derived. The results are applied to the linear birth and death process (λj=jλ, µj=jμ) with catastrophes of several different types.

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