761 research outputs found
An evolve-then-correct reduced order model for hidden fluid dynamics
In this paper, we put forth an evolve-then-correct reduced order modeling
approach that combines intrusive and nonintrusive models to take hidden
physical processes into account. Specifically, we split the underlying dynamics
into known and unknown components. In the known part, we first utilize an
intrusive Galerkin method projected on a set of basis functions obtained by
proper orthogonal decomposition. We then formulate a recurrent neural network
emulator based on the assumption that observed data is a manifestation of all
relevant processes. We further enhance our approach by using an orthonormality
conforming basis interpolation approach on a Grassmannian manifold to address
off-design conditions. The proposed framework is illustrated here with the
application of two-dimensional co-rotating vortex simulations under modeling
uncertainty. The results demonstrate highly accurate predictions underlining
the effectiveness of the evolve-then-correct approach toward realtime
simulations, where the full process model is not known a priori
An Improved, Highly Efficient Method for the Synthesis of Bisphenols
An efficient synthesis of bisphenols is described by condensation of substituted phenols with corresponding cyclic ketones in presence of cetyltrimethylammonium chloride and 3-mercaptopropionic acid as a catalyst in extremely high purity and yields
Heterojunction Hybrid Devices from Vapor Phase Grown MoS
We investigate a vertically-stacked hybrid photodiode consisting of a thin
n-type molybdenum disulfide (MoS) layer transferred onto p-type silicon.
The fabrication is scalable as the MoS is grown by a controlled and
tunable vapor phase sulfurization process. The obtained large-scale p-n
heterojunction diodes exhibit notable photoconductivity which can be tuned by
modifying the thickness of the MoS layer. The diodes have a broad
spectral response due to direct and indirect band transitions of the nanoscale
MoS. Further, we observe a blue-shift of the spectral response into the
visible range. The results are a significant step towards scalable fabrication
of vertical devices from two-dimensional materials and constitute a new
paradigm for materials engineering.Comment: 23 pages with 4 figures. This article has been published in
Scientific Reports. (26 June 2014, doi:10.1038/srep05458
A deep learning enabler for non-intrusive reduced order modeling of fluid flows
In this paper, we introduce a modular deep neural network (DNN) framework for
data-driven reduced order modeling of dynamical systems relevant to fluid
flows. We propose various deep neural network architectures which numerically
predict evolution of dynamical systems by learning from either using discrete
state or slope information of the system. Our approach has been demonstrated
using both residual formula and backward difference scheme formulas. However,
it can be easily generalized into many different numerical schemes as well. We
give a demonstration of our framework for three examples: (i) Kraichnan-Orszag
system, an illustrative coupled nonlinear ordinary differential equations, (ii)
Lorenz system exhibiting chaotic behavior, and (iii) a non-intrusive model
order reduction framework for the two-dimensional Boussinesq equations with a
differentially heated cavity flow setup at various Rayleigh numbers. Using only
snapshots of state variables at discrete time instances, our data-driven
approach can be considered truly non-intrusive, since any prior information
about the underlying governing equations is not required for generating the
reduced order model. Our \textit{a posteriori} analysis shows that the proposed
data-driven approach is remarkably accurate, and can be used as a robust
predictive tool for non-intrusive model order reduction of complex fluid flows.Comment: 36 pages, 21 figure
Peroxisome proliferator-activated receptors and thiazolidinediones in diabetic nephropathy
Diabetic nephropathy is global problem with several drugs into trial without much success the current article highlights the role of thiazolidinedioneβs in diabetic nephropathy by scrutinizing and reconnoitring the cellular and intracellular mechanism and shielding action and the role of peroxisome proliferator-activated gamma receptors (PPARΞ³) receptors. Not only anti-diabetic action but renal protective effect with evidence based study has been highlighted. PPAR Ξ³-is versatile target having numerous benefits and mainly preventing fibrosis in diabetic experimental model and some clinical case report yet, the benefits are not up to mark, since renal failure itself causes volume expansion and the thiazolidinedioneβs (TZDs) also preserve salt and water and lead to congestive heart failure which constraints its clinical application. Dual activators and balaglitazone selective PPAR modulator are having upcoming potential for treatment of diabetic nephropathy. Further detail investigation on such drug is needed to explore. However adverse effect like heart failure, osteoporosis and volume expansion effect over-rides the beneficial effect thus limiting its clinical use of currently available TZDs
Effects of Anatomy and Particle Size on Nasal Sprays and Nebulizers
To study the effects of nasal deformity on aerosol penetration past the nasal valve (NV) for varying particle sizes using sprays or nebulizers
Physiological and behavioral effects of animal-assisted interventions for therapy dogs in pediatric oncology settings
Over the past two decades, animal-assisted interventions (AAIs), defined as the purposeful incorporation of specially trained animals in services to improve human health, have become increasingly popular in clinical settings. However, to date, there have been few rigorously-designed studies aimed at examining the impact of AAIs on therapy animals, despite a notable potential for stress. The current study measured physiological and behavioral stress indicators in therapy dogs who participated in AAI sessions in pediatric oncology settings, while also examining the psychosocial effects for patients and their parents. This manuscript describes the studyβs canine stress findings. Methods: A total of 26 therapy dog-handler teams were paired with newly diagnosed children with cancer at five childrenβs hospitals in the United States. These teams provided regular AAI visits to the child and his/her parent(s) for a period of four months. The teams completed a demographic form, the Canine Behavioral Assessment & Research Questionnaire (C-BARQ), and a self-report survey to document the types of activities that occurred during each session. Canine saliva was also collected at five baseline time points and 20 minutes after the start of study sessions for cortisol analysis, and all study sessions were video recorded to document the dogβs behavior via an ethogram measure. Results: Data showed no significant differences in salivary cortisol levels between baseline (0.51Β΅g/dL) and AAI sessions (0.44Β΅g/dL), p = 0.757. Higher salivary cortisol was significantly associated with a higher number of stress behaviors per session (p = 0.039). There was a significant relationship between stress and affiliative session behaviors (pConclusions:Results show that therapy dogs did not have significantly increased physiological stress responses, nor did they exhibit significantly more stress-related behaviors than affiliative-related behaviors, while participating in AAIs in pediatric oncology settings. The significant relationship between canine cortisol and behavior, thus strengthening the argument for the use of cortisol in canine well-being research. This study discusses the importance of further investigation to confirm these findings, which may lead to enhanced canine involvement in hospital settings
Data-driven malaria prevalence prediction in large densely populated urban holoendemic sub-Saharan West Africa
Over 200 million malaria cases globally lead to half-million deaths annually. The development of malaria prevalence prediction systems to support malaria care pathways has been hindered by lack of data, a tendency towards universal "monolithic" models (one-size-fits-all-regions) and a focus on long lead time predictions. Current systems do not provide short-term local predictions at an accuracy suitable for deployment in clinical practice. Here we show a data-driven approach that reliably produces one-month-ahead prevalence prediction within a densely populated all-year-round malaria metropolis of over 3.5 million inhabitants situated in Nigeria which has one of the largest global burdens of P. falciparum malaria. We estimate one-month-ahead prevalence in a unique 22-years prospective regional dataset of >β9βΓβ10^{4} participants attending our healthcare services. Our system agrees with both magnitude and direction of the prediction on validation data achieving MAEββ€β6βΓβ10^{-2}, MSEββ€β7βΓβ10^{-3}, PCC (median 0.63, IQR 0.3) and with more than 80% of estimates within a (+β0.1 to -β0.05) error-tolerance range which is clinically relevant for decision-support in our holoendemic setting. Our data-driven approach could facilitate healthcare systems to harness their own data to support local malaria care pathways
Computed nasal resistance compared with patient-reported symptoms in surgically treated nasal airway passages: A preliminary report
Background:Nasal airway obstruction (NAO) is a common health condition impacting mood, energy, recreation, sleep, and overall quality of life. Nasal surgery often addresses NAO but the results are sometimes unsatisfactory. Evaluating surgical treatment efficacy could be improved if objective tests were available that correlated with patient-reported measures of symptoms. The goal of this study was to develop methods for comparing nasal resistance computed by computational fluid dynamics (CFD) models with patient-reported symptoms of NAO using early data from a 4-year prospective study.Methods:Computed tomography (CT) scans and patient-reported scores from the Nasal Obstruction Symptom Evaluation (NOSE) scale and a visual analog scale (VAS) measuring unilateral airflow sensation were obtained pre- and postoperatively in two NAO patients showing no significant mucosal asymmetry who were successfully treated with functional nasal surgery, including septoplasty. Pre- and postsurgery CFD models were created from the CT scans. Numerical simulation of steady-state inspiratory airflow was used to calculate bilateral and unilateral CFD-derived nasal resistance (CFD-NR).Results:In both subjects, NOSE and VAS scores improved after surgery, bilateral CFD-NR decreased, and unilateral CFD-NR decreased on the affected side. In addition, NOSE and VAS scores tracked with unilateral CFD-NR on the affected side.Conclusion:These preliminary results suggest a possible correlation between unilateral NR and patient-reported symptoms and imply that analysis of unilateral obstruction should focus on the affected side. A formal investigation of unilateral CFD-NR and patient-reported symptoms in a series of NAO patients is needed to determine if these variables are correlated
Tissue Microenvironments Define and Get Reinforced by Macrophage Phenotypes in Homeostasis or during Inflammation, Repair and Fibrosis
Current macrophage phenotype classifications are based on distinct in vitro culture conditions that do not adequately mirror complex tissue environments. In vivo monocyte progenitors populate all tissues for immune surveillance which supports the maintenance of homeostasis as well as regaining homeostasis after injury. Here we propose to classify macrophage phenotypes according to prototypical tissue environments, e.g. as they occur during homeostasis as well as during the different phases of (dermal) wound healing. In tissue necrosis and/or infection, damage- and/or pathogen-associated molecular patterns induce proinflammatory macrophages by Toll-like receptors or inflammasomes. Such classically activated macrophages contribute to further tissue inflammation and damage. Apoptotic cells and antiinflammatory cytokines dominate in postinflammatory tissues which induce macrophages to produce more antiinflammatory mediators. Similarly, tumor-associated macrophages also confer immunosuppression in tumor stroma. Insufficient parenchymal healing despite abundant growth factors pushes macrophages to gain a profibrotic phenotype and promote fibrocyte recruitment which both enforce tissue scarring. Ischemic scars are largely devoid of cytokines and growth factors so that fibrolytic macrophages that predominantly secrete proteases digest the excess extracellular matrix. Together, macrophages stabilize their surrounding tissue microenvironments by adapting different phenotypes as feed-forward mechanisms to maintain tissue homeostasis or regain it following injury. Furthermore, macrophage heterogeneity in healthy or injured tissues mirrors spatial and temporal differences in microenvironments during the various stages of tissue injury and repair. Copyright (C) 2012 S. Karger AG, Base
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