125 research outputs found
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Long Time Propagation of Stochasticity by Dynamical Polynomial Chaos Expansions
Stochastic differential equations (SDEs) and stochastic partial differential equations (SPDEs) play an important role in many areas of engineering and applied sciences such as atmospheric sciences, mechanical and aerospace engineering, geosciences, and finance. Equilibrium statistics and long-time solutions of these equations are pertinent to many applications. Typically, these models contain several uncertain parameters which need to be propagated in order to facilitate uncertainty quantification and prediction. Correspondingly, in this thesis, we propose a generalization of the Polynomial Chaos (PC) framework for long-time solutions of SDEs and SPDEs driven by Brownian motion forcing.
Polynomial chaos expansions (PCEs) allow us to propagate uncertainties in the coefficients of these equations to the statistics of their solutions. Their main advantages are: (i) they replace stochastic equations by systems of deterministic equations; and (ii) they provide fast convergence. Their main challenge is that the computational cost becomes prohibitive when the dimension of the parameters modeling the stochasticity is even moderately large. In particular, for equations with Brownian motion forcing, the long-time simulation by PC-based methods is notoriously difficult as the dimension of stochastic variables increases with time.
With the goal in mind to deliver computationally efficient numerical algorithms for stochastic equations in the long time, our main strategy is to leverage the intrinsic sparsity in the dynamics by identifying the influential random parameters and construct spectral approximations to the solutions in terms of those relevant variables. Once this strategy is employed dynamically in time, using online constructions, approximations can retain their sparsity and accuracy; even for long times. To this end, exploiting Markov property of Brownian motion, we present a restart procedure that allows PCEs to expand the solutions at future times in terms of orthogonal polynomials of the measure describing the solution at a given time and the future Brownian motion. In case of SPDEs, the Karhunen-Loeve expansion (KLE) is applied at each restart to select the influential variables and keep the dimensionality minimal. Using frequent restarts and low degree polynomials, the algorithms are able to capture long-time solutions accurately. We will also introduce, using the same principles, a similar algorithm based on a stochastic collocation method for the solutions of SDEs.
We apply the methods to the numerical simulation of linear and nonlinear SDEs, and stochastic Burgers and Navier-Stokes equations with white noise forcing. Our methods also allow us to incorporate time-independent random coefficients such as a random viscosity. We propose several numerical simulations, and show that the algorithms compare favorably with standard Monte Carlo methods in terms of accuracy and computational times. To demonstrate the efficiency of the algorithms for long-time simulations, we compute invariant measures of the solutions when they exist
Alginates: From the ocean to gastroesophageal reflux disease treatment
Reckitt Benckiser Turke
Cor triatriatum sinister: two cases diagnosed in adulthood and a review of literature
Cor triatriatum sinister is a rare condition caused by a membrane within left atrium that separates pulmonary veins from mitral valve (10). While the condition is usually diagnosed at childhood, rare presentation during adulthood is observed when the membrane is incomplete. We report two cases of incomplete cor triatriatum sinister diagnosed during adulthood and review literature for this rare anomaly
Synthesis and bio-molecular study of (+)-N-Acetyl-α-amino acid dehydroabietylamine derivative for the selective therapy of hepatocellular carcinoma
Background: The purpose of present work is to synthesize novel (+)-Dehydroabietylamine derivatives (DAAD) using N-acetyl-α-amino acid conjugates and determine its cytotoxic effects on hepatocellular carcinoma cells. Methods: An analytical study was conducted to explore cytotoxic activity of DAAD on hepatocellular carcinoma cell lines. The cytotoxicity effect was recorded using sulforhodamine B technique. Cell cycle analysis was performed using Propidium Iodide (PI) staining. Based on cell morphology, anti growth activity and microarray findings of DAAD2 treatment, Comet assay, Annexin V/PI staining, Immunoperoxidase assay and western blots were performed accoringly. Results: Hep3B cells were found to be the most sensitive with IC50 of 2.00 ± 0.4 μM against (+)-N-(N-Acetyl-L-Cysteine)-dehydroabietylamine as DAAD2. In compliance to time dependent morphological changes of low cellular confluence, detachment and rounding of DAAD2 treated cells; noticeable changes in G2/M phase were recorded may be leading to cell cycle cessation. Up-regulation (5folds) of TUBA1A gene in Hep3B cells was determined in microarray experiments. Apoptotic mode of cell death was evaluated using standardized staining procedures including comet assay and annexin V/PI staining, Immuno-peroxidase assay. Using western blotting technique, caspase dependant apoptotic mode of cell death was recorded against Hep3B cell line. Conclusion: It is concluded that a novel DAAD2 with IC50 values less than 8 μM can induce massive cell attenuation following caspase dependent apoptotic cell death in Hep3B cells. Moreover, the corelation study indicated that DAAD2 may have vital influence on cell prolifration properties. © 2016 The Author(s)
Hematopoietic Cell Transplantation Cures Adenosine Deaminase 2 Deficiency: Report on 30 Patients
PURPOSE: Deficiency of adenosine deaminase 2 (DADA2) is an inherited inborn error of immunity, characterized by autoinflammation (recurrent fever), vasculopathy (livedo racemosa, polyarteritis nodosa, lacunar ischemic strokes, and intracranial hemorrhages), immunodeficiency, lymphoproliferation, immune cytopenias, and bone marrow failure (BMF). Tumor necrosis factor (TNF-α) blockade is the treatment of choice for the vasculopathy, but often fails to reverse refractory cytopenia. We aimed to study the outcome of hematopoietic cell transplantation (HCT) in patients with DADA2.
METHODS: We conducted a retrospective study on the outcome of HCT in patients with DADA2. The primary outcome was overall survival (OS).
RESULTS: Thirty DADA2 patients from 12 countries received a total of 38 HCTs. The indications for HCT were BMF, immune cytopenia, malignancy, or immunodeficiency. Median age at HCT was 9 years (range: 2-28 years). The conditioning regimens for the final transplants were myeloablative (n = 20), reduced intensity (n = 8), or non-myeloablative (n = 2). Donors were HLA-matched related (n = 4), HLA-matched unrelated (n = 16), HLA-haploidentical (n = 2), or HLA-mismatched unrelated (n = 8). After a median follow-up of 2 years (range: 0.5-16 years), 2-year OS was 97%, and 2-year GvHD-free relapse-free survival was 73%. The hematological and immunological phenotypes resolved, and there were no new vascular events. Plasma ADA2 enzyme activity normalized in 16/17 patients tested. Six patients required more than one HCT.
CONCLUSION: HCT was an effective treatment for DADA2, successfully reversing the refractory cytopenia, as well as the vasculopathy and immunodeficiency.
CLINICAL IMPLICATIONS: HCT is a definitive cure for DADA2 with > 95% survival
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Open-face tunnelling effects on non-displacement piles in clay ii) Tunnelling beneath loaded piles and analytical modelling
Results from centrifuge modelling of tunnelling beneath loaded non-displacement piles in clay are presented in this paper; the principal variables were soil strength, pile loading and pile position relative to the tunnel. The details of the experimental set-up and the importance of understanding the loading history of the soil and the piles are presented in a companion paper. The subsurface pile–soil interaction was captured through particle image velocimetry; the effects of pile loading and pile position were found to have a significant impact on pile settlements. Analysis of tunnel–pile interaction through t–z load-transfer modelling of the pile–soil interface is presented using the approach described in the companion paper. The mechanisms observed in the centrifuge tests are predicted reasonably well. A significant improvement in the prediction of the induced pile loading and settlements was achieved with the inclusion of plasticity and simple power-law non-linearity for the soil.The first author acknowledges financial support provided by Arup Tunnelling and the Engineering and Physical Sciences Research Council for an Industrial Case Studentship
Evaluation and Management of Deficiency of Adenosine Deaminase 2: An International Consensus Statement
IMPORTANCE: Deficiency of adenosine deaminase 2 (DADA2) is a recessively inherited disease characterized by systemic vasculitis, early-onset stroke, bone marrow failure, and/or immunodeficiency affecting both children and adults. DADA2 is among the more common monogenic autoinflammatory diseases, with an estimate of more than 35 000 cases worldwide, but currently, there are no guidelines for diagnostic evaluation or management. OBJECTIVE: To review the available evidence and develop multidisciplinary consensus statements for the evaluation and management of DADA2. EVIDENCE REVIEW: The DADA2 Consensus Committee developed research questions based on data collected from the International Meetings on DADA2 organized by the DADA2 Foundation in 2016, 2018, and 2020. A comprehensive literature review was performed for articles published prior to 2022. Thirty-two consensus statements were generated using a modified Delphi process, and evidence was graded using the Oxford Center for Evidence-Based Medicine Levels of Evidence. FINDINGS: The DADA2 Consensus Committee, comprising 3 patient representatives and 35 international experts from 18 countries, developed consensus statements for (1) diagnostic testing, (2) screening, (3) clinical and laboratory evaluation, and (4) management of DADA2 based on disease phenotype. Additional consensus statements related to the evaluation and treatment of individuals with DADA2 who are presymptomatic and carriers were generated. Areas with insufficient evidence were identified, and questions for future research were outlined. CONCLUSIONS AND RELEVANCE: DADA2 is a potentially fatal disease that requires early diagnosis and treatment. By summarizing key evidence and expert opinions, these consensus statements provide a framework to facilitate diagnostic evaluation and management of DADA2
Hematopoietic Cell Transplantation Cures Adenosine Deaminase 2 Deficiency : Report on 30 Patients
Correction; Early Access: ' DOI: 10.1007/s10875-022-01280-y Early Access: APR 2022Purpose Deficiency of adenosine deaminase 2 (DADA2) is an inherited inborn error of immunity, characterized by autoinflammation (recurrent fever), vasculopathy (livedo racemosa, polyarteritis nodosa, lacunar ischemic strokes, and intracranial hemorrhages), immunodeficiency, lymphoproliferation, immune cytopenias, and bone marrow failure (BMF). Tumor necrosis factor (TNF-alpha) blockade is the treatment of choice for the vasculopathy, but often fails to reverse refractory cytopenia. We aimed to study the outcome of hematopoietic cell transplantation (HCT) in patients with DADA2. Methods We conducted a retrospective study on the outcome of HCT in patients with DADA2. The primary outcome was overall survival (OS). Results Thirty DADA2 patients from 12 countries received a total of 38 HCTs. The indications for HCT were BMF, immune cytopenia, malignancy, or immunodeficiency. Median age at HCT was 9 years (range: 2-28 years). The conditioning regimens for the final transplants were myeloablative (n = 20), reduced intensity (n = 8), or non-myeloablative (n = 2). Donors were HLA-matched related (n = 4), HLA-matched unrelated (n = 16), HLA-haploidentical (n = 2), or HLA-mismatched unrelated (n = 8). After a median follow-up of 2 years (range: 0.5-16 years), 2-year OS was 97%, and 2-year GvHD-free relapse-free survival was 73%. The hematological and immunological phenotypes resolved, and there were no new vascular events. Plasma ADA2 enzyme activity normalized in 16/17 patients tested. Six patients required more than one HCT. Conclusion HCT was an effective treatment for DADA2, successfully reversing the refractory cytopenia, as well as the vasculopathy and immunodeficiency. Clinical Implications HCT is a definitive cure for DADA2 with > 95% survival.Peer reviewe
Volume CXIV, Number 4, November 7, 1996
Objective: Turner syndrome (TS) is a chromosomal disorder caused by complete or partial X chromosome monosomy that manifests various clinical features depending on the karyotype and on the genetic background of affected girls. This study aimed to systematically investigate the key clinical features of TS in relationship to karyotype in a large pediatric Turkish patient population.Methods: Our retrospective study included 842 karyotype-proven TS patients aged 0-18 years who were evaluated in 35 different centers in Turkey in the years 2013-2014.Results: The most common karyotype was 45,X (50.7%), followed by 45,X/46,XX (10.8%), 46,X,i(Xq) (10.1%) and 45,X/46,X,i(Xq) (9.5%). Mean age at diagnosis was 10.2±4.4 years. The most common presenting complaints were short stature and delayed puberty. Among patients diagnosed before age one year, the ratio of karyotype 45,X was significantly higher than that of other karyotype groups. Cardiac defects (bicuspid aortic valve, coarctation of the aorta and aortic stenosis) were the most common congenital anomalies, occurring in 25% of the TS cases. This was followed by urinary system anomalies (horseshoe kidney, double collector duct system and renal rotation) detected in 16.3%. Hashimoto's thyroiditis was found in 11.1% of patients, gastrointestinal abnormalities in 8.9%, ear nose and throat problems in 22.6%, dermatologic problems in 21.8% and osteoporosis in 15.3%. Learning difficulties and/or psychosocial problems were encountered in 39.1%. Insulin resistance and impaired fasting glucose were detected in 3.4% and 2.2%, respectively. Dyslipidemia prevalence was 11.4%.Conclusion: This comprehensive study systematically evaluated the largest group of karyotype-proven TS girls to date. The karyotype distribution, congenital anomaly and comorbidity profile closely parallel that from other countries and support the need for close medical surveillance of these complex patients throughout their lifespa
Synthesis and bio-molecular study of (+)-N-Acetyl-α-amino acid dehydroabietylamine derivative for the selective therapy of hepatocellular carcinoma
BACKGROUND: The purpose of present work is to synthesize novel (+)-Dehydroabietylamine derivatives (DAAD) using N-acetyl-α-amino acid conjugates and determine its cytotoxic effects on hepatocellular carcinoma cells. METHODS: An analytical study was conducted to explore cytotoxic activity of DAAD on hepatocellular carcinoma cell lines. The cytotoxicity effect was recorded using sulforhodamine B technique. Cell cycle analysis was performed using Propidium Iodide (PI) staining. Based on cell morphology, anti growth activity and microarray findings of DAAD2 treatment, Comet assay, Annexin V/PI staining, Immunoperoxidase assay and western blots were performed accoringly. RESULTS: Hep3B cells were found to be the most sensitive with IC(50) of 2.00 ± 0.4 μM against (+)-N-(N-Acetyl-L-Cysteine)-dehydroabietylamine as DAAD2. In compliance to time dependent morphological changes of low cellular confluence, detachment and rounding of DAAD2 treated cells; noticeable changes in G(2)/M phase were recorded may be leading to cell cycle cessation. Up-regulation (5folds) of TUBA1A gene in Hep3B cells was determined in microarray experiments. Apoptotic mode of cell death was evaluated using standardized staining procedures including comet assay and annexin V/PI staining, Immuno-peroxidase assay. Using western blotting technique, caspase dependant apoptotic mode of cell death was recorded against Hep3B cell line. CONCLUSION: It is concluded that a novel DAAD2 with IC(50) values less than 8 μM can induce massive cell attenuation following caspase dependent apoptotic cell death in Hep3B cells. Moreover, the corelation study indicated that DAAD2 may have vital influence on cell prolifration properties. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12885-016-2942-5) contains supplementary material, which is available to authorized users
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