280 research outputs found
An integrative approach to conceptualizing sustainable resilience
Vulnerability, resilience, and sustainability are three concepts commonly used in assessing the quality of a variety of systems. While each can be applied independently when performing risk analysis, there is growing interest across multiple disciplines in understanding how these concepts can be integrated when considering complex adaptive systems, such as communities. In this paper, we identify issues related to the use of these respective concepts in assessing complex adaptive systems, and describe how these issues may produce imbalanced results and maladaptive outcomes. We identify five critical areas where alignment and integration across concepts can lead to improved system assessment. As a result, we introduce a new paradigm, sustainable resilience, in which these concepts are integrated to enable alignment of adaptation and transformation strategies with desired resilience outcomes. This work provides the foundation for the development of an integrated assessment framework to help guide informed risk-based decisionmaking for sustainable and resilient systems
An integrated and dynamic framework for assessing sustainable resilience in complex adaptive systems
Growing awareness of climate change and resulting impacts to communities have generated increasing interest in understanding relationships between vulnerability, resilience, sustainability, and adaptive capacity, and how these concepts can be combined to better assess the quality of complex adaptive systems over time. Previous work has described interactions between these concepts and the value-added should they be integrated and applied in a strategic manner, resulting in a new understanding of system quality defined as sustainable resilience. However, a framework for explicitly integrating vulnerability, resilience, and sustainability assessment to develop understanding of system sustainable resilience has yet to be proposed. This paper presents a high-level, integrated and dynamic framework for assessing sustainable resilience for complex adaptive systems. We provide a set of functional definitions, a description of each step in the proposed assessment process, and walk through an example application of the framework, including a discussion of preliminary analyses, technical methodologies employed, and suggested future advances
Agent-Based Model of Navigable Inland Waterway Tow Operation Procedures
Transportation modeling within the context of extreme weather events induced by climate change is critical to understand and improve the resilience of transport systems as the world moves further into the 21st century. Among transportation modes, navigable inland waterways in particular face severe challenges to their future reliability as a result of extreme weather events. The economic implications of inland waterway operational efficiencies on commercial shipping have been studied in detail for several decades. Less well understood, however, are the effects of tow operation procedures enacted during adverse river conditions that have resulted from extreme weather events. This paper describes a model of a waterway segment that simulates stakeholder decision making and tow operator behavior to provide stakeholders with insights into the possible benefits of waterway action plans as operational guidance documents. Simulations run for a test area of the navigable inland waterway system indicated that operational procedures recommended in waterway action plans might have a significant impact on waterway operational efficiencies, which suggests that the model may be a useful decision-support tool for waterway stakeholders
Modeling the clonal heterogeneity of stem cells
Recent experimental studies suggest that tissue stem cell pools are composed of functionally diverse clones. Metapopulation models in ecology concentrate on collections of populations and their role in stabilizing coexistence and maintaining selected genetic or epigenetic variation. Such models are characterized by expansion and extinction of spatially distributed populations. We develop a mathematical framework derived from the multispecies metapopulation model of Tilman et al (1994) to study the dynamics of heterogeneous stem cell metapopulations. In addition to normal stem cells, the model can be applied to cancer cell populations and their response to treatment. In our model disturbances may lead to expansion or contraction of cells with distinct properties, reflecting proliferation, apoptosis, and clonal competition. We first present closed-form expressions for the basic model which defines clonal dynamics in the presence of exogenous global disturbances. We then extend the model to include disturbances which are periodic and which may affect clones differently. Within the model framework, we propose a method to devise an optimal strategy of treatments to regulate expansion, contraction, or mutual maintenance of cells with specific properties
Integrating Extrinsic and Intrinsic Cues into a Minimal Model of Lineage Commitment for Hematopoietic Progenitors
Autoregulation of transcription factors and cross-antagonism between lineage-specific transcription factors are a recurrent theme in cell differentiation. An equally prevalent event that is frequently overlooked in lineage commitment models is the upregulation of lineage-specific receptors, often through lineage-specific transcription factors. Here, we use a minimal model that combines cell-extrinsic and cell-intrinsic elements of regulation in order to understand how both instructive and stochastic events can inform cell commitment decisions in hematopoiesis. Our results suggest that cytokine-mediated positive receptor feedback can induce a “switch-like” response to external stimuli during multilineage differentiation by providing robustness to both bipotent and committed states while protecting progenitors from noise-induced differentiation or decommitment. Our model provides support to both the instructive and stochastic theories of commitment: cell fates are ultimately driven by lineage-specific transcription factors, but cytokine signaling can strongly bias lineage commitment by regulating these inherently noisy cell-fate decisions with complex, pertinent behaviors such as ligand-mediated ultrasensitivity and robust multistability. The simulations further suggest that the kinetics of differentiation to a mature cell state can depend on the starting progenitor state as well as on the route of commitment that is chosen. Lastly, our model shows good agreement with lineage-specific receptor expression kinetics from microarray experiments and provides a computational framework that can integrate both classical and alternative commitment paths in hematopoiesis that have been observed experimentally
Hematopoietic Stem Cells Contribute to Lymphatic Endothelium
Although the lymphatic system arises as an extension of venous vessels in the embryo, little is known about the role of circulating progenitors in the maintenance or development of lymphatic endothelium. Here, we investigated whether hematopoietic stem cells (HSCs) have the potential to give rise to lymphatic endothelial cells (LEC). mice resulted in the incorporation of donor-derived LEC into the lymphatic vessels of spontaneously arising intestinal tumors.Our results indicate that HSCs can contribute to normal and tumor associated lymphatic endothelium. These findings suggest that the modification of HSCs may be a novel approach for targeting tumor metastasis and attenuating diseases of the lymphatic system
Effect of Composition on Electrical and Optical Properties of Thin Films of Amorphous GaxSe100−x Nanorods
We report the electrical and optical studies of thin films of a-GaxSe100−x nanorods (x = 3, 6, 9 and 12). Thin films of a-GaxSe100−x nanorods have been synthesized thermal evaporation technique. DC electrical conductivity of deposited thin films of a-GaxSe100−x nanorods is measured as a function of temperature range from 298 to 383 K. An exponential increase in the dc conductivity is observed with the increase in temperature, suggesting thereby a semiconducting behavior. The estimated value of activation energy decreases on incorporation of dopant (Ga) content in the Se system. The calculated value of pre-exponential factor (σ0) is of the order of 101 Ω−1 cm−1, which suggests that the conduction takes place in the band tails of localized states. It is suggested that the conduction is due to thermally assisted tunneling of the carriers in the localized states near the band edges. On the basis of the optical absorption measurements, an indirect optical band gap is observed in this system, and the value of optical band gap decreases on increasing Ga concentration
Phase 1/2 study of sorafenib added to cladribine, high-dose cytarabine, G-CSF, and mitoxantrone in untreated AML
© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.The multikinase inhibitor sorafenib improves event-free survival (EFS) when used with 7 + 3 in adults with newly-diagnosed acute myeloid leukemia (AML), irrespective of the FLT3-mutation status. Here, we evaluated adding sorafenib to cladribine, high-dose cytarabine, granulocyte colony–stimulating factor, and mitoxantrone (CLAG-M) in a phase 1/2 trial of 81 adults aged ≤60 years with newly diagnosed AML. Forty-six patients were treated in phase 1 with escalating doses of sorafenib and mitoxantrone. No maximum tolerated dose was reached, and a regimen including mitoxantrone 18 mg/m2 per day and sorafenib 400 mg twice daily was declared the recommended phase 2 dose (RP2D). Among 41 patients treated at RP2D, a measurable residual disease–negative complete remission (MRD– CR) rate of 83% was obtained. Four-week mortality was 2%. One-year overall survival (OS) and EFS were 80% and 76%, without differences in MRD– CR rates, OS, or EFS between patients with or without FLT3-mutated disease. Comparing outcomes using CLAG-M/sorafenib with those of a matched cohort of 76 patients treated with CLAG-M alone, multivariable-adjusted survival estimates were improved for 41 patients receiving CLAG-M/sorafenib at RP2D (OS: hazard ratio,0.24 [95% confidence interval, 0.07-0.82]; P = .023; EFS: hazard ratio, 0.16 [95% confidence interval, 0.05-0.53]; P = .003). Benefit was limited to patients with intermediate-risk disease (univariate analysis: P = .01 for OS; P = .02 for EFS). These data suggest that CLAG-M/sorafenib is safe and improves OS and EFS relative to CLAG-M alone, with benefits primarily in patients with intermediate-risk disease. The trial was registered at www.clinicaltrials.gov as #NCT02728050.The CLAG-M/sorafenib trial was supported by Bayer Pharmaceuticals Inc. A.B.H. was supported by an ASCO Young Investigator award.Peer reviewe
In Support of a Patient-Driven Initiative and Petition to Lower the High Price of Cancer Drugs
Comment in
Lowering the High Cost of Cancer Drugs--III. [Mayo Clin Proc. 2016]
Lowering the High Cost of Cancer Drugs--I. [Mayo Clin Proc. 2016]
Lowering the High Cost of Cancer Drugs--IV. [Mayo Clin Proc. 2016]
In Reply--Lowering the High Cost of Cancer Drugs. [Mayo Clin Proc. 2016]
US oncologists call for government regulation to curb drug price rises. [BMJ. 2015
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