A Non-intrusive Approach for Physics-constrained Learning with Application to Fuel Cell Modeling

A data-driven model augmentation framework, referred to as Weakly-coupled Integrated Inference and Machine Learning (IIML), is presented to improve the predictive accuracy of physical models. In contrast to parameter calibration, this work seeks corrections to the structure of the model by a) inferring augmentation fields that are consistent with the underlying model, and b) transforming these fields into corrective model forms. The proposed approach couples the inference and learning steps in a weak sense via an alternating optimization approach. This coupling ensures that the augmentation fields remain learnable and maintain consistent functional relationships with local modeled quantities across the training dataset. An iterative solution procedure is presented in this paper, removing the need to embed the augmentation function during the inference process. This framework is used to infer an augmentation introduced within a Polymer electrolyte membrane fuel cell (PEMFC) model using a small amount of training data (from only 14 training cases.) These training cases belong to a dataset consisting of high-fidelity simulation data obtained from a high-fidelity model of a first generation Toyota Mirai. All cases in this dataset are characterized by different inflow and outflow conditions on the same geometry. When tested on 1224 different configurations, the inferred augmentation significantly improves the predictive accuracy for a wide range of physical conditions. Predictions and available data for the current density distribution are also compared to demonstrate the predictive capability of the model for quantities of interest which were not involved in the inference process. The results demonstrate that the weakly-coupled IIML framework offers sophisticated and robust model augmentation capabilities without requiring extensive changes to the numerical solver

Ph3P Catalyzed Synthesis of Alkyl 2-(4-Oxopyridin-1(4H)-yl)acrylates by Nucleophilic Addition to Alkyl Propiolates

4-Hydroxypyridine undergoes a smooth reaction with alkyl propiolates in the presence of triphenylphosphine to produce and β-substituted alkyl acrylate products. When the reaction was performed with 4-hydroxyquinoline only  α-substituted alkyl acrylates were obtained.Keywords: 4-hydroxypyridine, 4-hydroxyquinoline, Alkyl Acrylates, Alkyl Propiolates, Triphenylphosphin

Synthesis and characterization of functionalized dihydropyrimidinones via one-pot isocyanide-based three-component reaction of N-formyl urea and dialkyl ACETYLENEDICARBOXYLATES

The reactive intermediate generated by the addition of alkyl isocyanides to dialkyl acetylenedicarboxylates was trapped by N-formyl urea to produce highly functionalized dihydropyrimidinones in fairly good yields

Transcriptome Analysis of Human Diabetic Kidney Disease

OBJECTIVE: Diabetic kidney disease (DKD) is the single leading cause of kidney failure in the U.S., for which a cure has not yet been found. The aim of our study was to provide an unbiased catalog of gene-expression changes in human diabetic kidney biopsy samples. RESEARCH DESIGN AND METHODS: Affymetrix expression arrays were used to identify differentially regulated transcripts in 44 microdissected human kidney samples. DKD samples were significant for their racial diversity and decreased glomerular filtration rate (~25–35 mL/min). Stringent statistical analysis, using the Benjamini-Hochberg corrected two-tailed t test, was used to identify differentially expressed transcripts in control and diseased glomeruli and tubuli. Two different web-based algorithms were used to define differentially regulated pathways. RESULTS: We identified 1,700 differentially expressed probesets in DKD glomeruli and 1,831 in diabetic tubuli, and 330 probesets were commonly differentially expressed in both compartments. Pathway analysis highlighted the regulation of Ras homolog gene family member A, Cdc42, integrin, integrin-linked kinase, and vascular endothelial growth factor signaling in DKD glomeruli. The tubulointerstitial compartment showed strong enrichment for inflammation-related pathways. The canonical complement signaling pathway was determined to be statistically differentially regulated in both DKD glomeruli and tubuli and was associated with increased glomerulosclerosis even in a different set of DKD samples. CONCLUSIONS: Our studies have cataloged gene-expression regulation and identified multiple novel genes and pathways that may play a role in the pathogenesis of DKD or could serve as biomarkers

Direct electrochemical detection of clozapine by RuO2 nanoparticles-modified screen-printed electrode

This study introduces the sensitive electrochemical detection of clozapine with the use of a ruthenium(iv) oxide nanoparticle (RuO2 NP)-modified screen-printed electrode (RuO2 NPs/SPE). The electrochemical behaviors of clozapine at RuO2 NP/SPE have been examined via cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CHA). According to the results, the modified electrode has been accompanied by a decreasing over-potential (ca. 170 mV) and enhancement in the peak current (3 times) in comparison with the bare SPE. The results indicated that RuO2 NP/SPE markedly augmented electro-catalytic activities toward clozapine oxidation. In addition, linear responses have been observed in the range between 0.2 and 500.0 μM with a sensitivity of 0.076 μA μM-1 and a limitation of detection of 0.07 μM (3�). Moreover, the successful application of RuO2 NP/SPE has been seen in detecting clozapine in real samples, which showed satisfied recoveries. Therefore, outputs suggest that RuO2 NP/SPE will be promising for functional utilization. © 2020 The Royal Society of Chemistry

Fabrication of magnetic iron oxide-supported copper oxide nanoparticles (Fe3O4/CuO): Modified screen-printed electrode for electrochemical studies and detection of desipramine

The present investigation examines a sensitive electrochemical technique to detect desipramine through Fe3O4/CuO nanoparticles (NPs). Fe3O4/CuO NPs were synthesized via a coprecipitation procedure, and the products were characterized via energy disperse spectroscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and vibrating sample magnetometer. The voltage-current curve and differential pulse voltammetry examinations of Fe3O4/CuO-modified screen-printed electrode (Fe3O4/CuO/SPE) were followed by the determination of electro-catalytic activities toward desipramine oxidation in a phosphate buffer solution (pH = 7.0). In addition, the value of diffusion coefficient (D = 3.0 � 10-6 cm2 s-1) for desipramine was calculated. Then, based on the optimum conditions, it was observed that the currents of the oxidation peak were linearly proportionate to the concentration of desipramine in the broad range between 0.08 and 400.0 μM and LOD of 0.03 μM (S/N = 3). Finally, our new sensor was successfully utilized to detect desipramine in the real samples, with reasonable recovery in the range of 97.2 to 102.7. This journal is © 2020 The Royal Society of Chemistry