235 results match your criteria: "Bourns College of Engineering[Affiliation]"

Uniform magnetic behavior within arrays of magnetoelectric heterostructures is important for the development of reliable strain-mediated microdevices. Multiple mechanisms may contribute to observed nonuniform magnetization reversal including surface roughness, non-uniform strain, and fabrication induced imperfections. Here, Co/Ni microdisks of 7 µm diameter were produced on both [Pb(MgNb)O]-[PbTiO] with x = 0.

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The impact of hydrogenated vegetable oil (HVO) on the formation of secondary organic aerosol (SOA) from in-use heavy-duty diesel vehicles.

Sci Total Environ

May 2022

University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA; Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA. Electronic address:

This manuscript contains an assessment of tailpipe emissions and secondary aerosol formation from two in-use heavy-duty diesel vehicles (HDDVs) with different aftertreatment systems when operated with ultra-low sulfur diesel (ULSD) and hydrogenated vegetable oil (HVO) operated on a chassis dynamometer. Secondary aerosol formation was characterized from the HDDVs' diluted exhaust collected and photochemically aged in a 30 m mobile atmospheric chamber. Primary nitrogen oxide (NOx) and particulate matter (PM) emissions were reduced for both vehicles operating on HVO compared to ULSD.

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Wearable piezoresistive sensors are being developed as electronic skins (E-skin) for broad applications in human physiological monitoring and soft robotics. Tactile sensors with sufficient sensitivities, durability, and large dynamic ranges are required to replicate this critical component of the somatosensory system. Multiple micro/nanostructures, materials, and sensing modalities have been reported to address this need.

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Variability in Aromatic Aerosol Yields under Very Low NO Conditions at Different HO/RO Regimes.

Environ Sci Technol

January 2022

Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, Riverside, California 92507, United States.

Current chemical transport models generally use a constant secondary organic aerosol (SOA) yield to represent SOA formation from aromatic compounds under low NO conditions. However, a wide range of SOA yields (10 to 42%) from -xylene under low NO conditions is observed in this study. The chamber HO/RO ratio is identified as a key factor explaining SOA yield variability: higher SOA yields are observed for runs with a higher HO/RO ratio.

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The Influence of High-Energy Faceted TiO Supports on Co and Co-Ru Catalysts for Dry Methane Reforming.

Chem Asian J

February 2022

Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California Riverside, 446 Winston Chung Hall, 900 University Ave, Riverside, USA.

The reforming of methane from biogas has been proposed as a promising method of CO utilization. Co-based catalysts are promising candidates for dry methane reforming. However, the main constraints limiting the large-scale use of Co-based catalysts are deactivation through carbon deposition (coking) and sintering due to weak metal-support interaction.

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Cosolvent enhanced lignocellulosic fractionation tailoring lignin chemistry and enhancing lignin bioconversion.

Bioresour Technol

March 2022

Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, United States; Center for Bioenergy Innovation (CBI), Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States; Center for Renewable Carbon, Department of Forestry, Wildlife, and Fisheries, University of Tennessee Institute of Agriculture, Knoxville, TN 37996, United States. Electronic address:

Cosolvent Enhanced Lignocellulosic Fractionation (CELF) is an emerging solvolysis pretreatment to fractionate lignocellulosic biomass. Herein, the bioconversion performance of CELF lignin was fully evaluated for the first time. Results showed that CELF lignin possessed higher content of carboxylic acid OH, lower molecular weight, and disappeared β-O-4 and β-5 linkages compared to other two technical lignins including a conventional ethanol organosolv lignin (EOL) and a kraft lignin (KL).

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Product inhibition kinetics determinations - Substrate interaction affinity and enzymatic kinetics using one quantitative FRET assay.

Int J Biol Macromol

December 2021

Department of Bioengineering, Bourns College of Engineering, Biomedical Science, University of California at Riverside, 900 University Avenue, Riverside, CA 92521, USA; Biomedical Science, University of California at Riverside, 900 University Avenue, Riverside, CA 92521, USA. Electronic address:

Product inhibition is a common phenomenon during enzyme-catalyzed reactions. Almost all product molecules of an enzyme reaction should have some structural similarities to the substrate, and can thus still have affinities to the active site of the enzyme as product inhibitor. Currently, the characterizations of product inhibition are generally carried out by different methods to determine product binding affinity to the enzyme and the enzyme kinetics parameters, and then these parameters are combined to determine product inhibition.

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Protein-protein interactions play pivotal roles in life, and the protein interaction affinity confers specific protein interaction events in physiology or pathology. Förster resonance energy transfer (FRET) has been widely used in biological and biomedical research to detect molecular interactions in vitro and in vivo. The FRET assay provides very high sensitivity and efficiency.

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Specifics of Thermal Transport in Graphene Composites: Effect of Lateral Dimensions of Graphene Fillers.

ACS Appl Mater Interfaces

November 2021

Phonon Optimized Engineered Materials Center, University of California, Riverside, California 92521, United States.

We report on the investigation of thermal transport in noncured silicone composites with graphene fillers of different lateral dimensions. Graphene fillers are comprised of few-layer graphene flakes with lateral sizes in the range from 400 to 1200 nm and the number of atomic planes from 1 to ∼100. The distribution of the lateral dimensions and thicknesses of graphene fillers has been determined via atomic force microscopy statistics.

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urinary compatibility of Mg-Sr-Ag alloy in swine model.

Bioact Mater

January 2022

Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, CA, 92521, USA.

A biodegradable metallic ureteral stent with suitable mechanical properties and antibacterial activity remains a challenge. Here we reveal the scientific significance of a biodegradable Mg-Sr-Ag alloy with a favorable combination of balanced mechanical properties, adjustable indwelling time in urinary tract and evident antibacterial activity via experiments in a swine model. Attributed to the rheo-solidification process, equiaxial microstructure and significantly refined grains (average grain size: 27.

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Video-based calcification assay: A novel method for kinetic analysis of osteogenesis in live cultures.

MethodsX

February 2021

Department of Molecular, Cell & Systems Biology and Stem Cell Center, College of Natural and Agricultural Sciences, University of California Riverside, Riverside, CA, 92521, USA.

Traditional methods of quantifying osteoblast calcification in culture require the use of calcium sensitive dyes, such as Arsenazo III or Alizarin Red S, which have been successfully used for decades to assess osteogenesis. Because these dyes elicit a colorimetric change when reacted with a cell lysate and are cytotoxic to live cells, they forfeit the ability to trace calcification longitudinally over time. Here, we demonstrate that image analysis and quantification of calcification can be performed from a series of time-lapse images acquired from videos.

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Using an oxidation flow reactor to understand the effects of gasoline aromatics and ethanol levels on secondary aerosol formation.

Environ Res

September 2021

University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA, 92507, USA; Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA, 92521, USA. Electronic address:

Fuel type and composition affect tailpipe emissions and secondary aerosol production from mobile sources. This study assessed the influence of gasoline fuels with varying levels of aromatics and ethanol on the primary emissions and secondary aerosol formation from a flexible fuel vehicle equipped with a port fuel injection engine. The vehicle was exercised over the LA92 and US06 driving cycles using a chassis dynamometer.

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Physiochemical Properties of Biochar and Activated Carbon from Biomass Residue: Influence of Process Conditions to Adsorbent Properties.

ACS Omega

April 2021

Department of Chemical and Environmental Engineering, Bourns College of Engineering, UC, Riverside, 446 Winston Chung Hall, 900 University Avenue, Riverside, California 92507, United States.

This study evaluates the influence of hydrothermal carbonization (HTC) or slow pyrolysis (SP) process conditions on the physicochemical properties of precursor biochars and activated carbon (AC). The AC is achieved through a direct or a two-step method with subsequent chemical activation using KOH. A theory is developed on the biochar propensity to be chemically activated based on the lignocellulosic structure composition.

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Elucidation of native California Agave americana and Agave deserti biofuel potential: Compositional analysis.

PLoS One

October 2021

Center for Environmental Research and Technology, Bourns College of Engineering, University of California, Riverside, California, United States of America.

Because biofuels have the unique potential to be rapidly deployed in existing transportation fuel infrastructures, they should play a major role in helping California quickly meet its aggressive goals to substantially reduce greenhouse gas contributions by this major sector. Furthermore, energy crops are vital to significantly impact the State's large and burgeoning need for sustainable fuels. Among crops amenable to be grown in California to support fuel production, agave pose a particularly promising prospect, given their drought tolerance and high productivity on marginal land in a State prone to drought and limited water resources.

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Isopeptidase Kinetics Determination by a Real Time and Sensitive qFRET Approach.

Biomolecules

April 2021

Department of Bioengineering, Bourns College of Engineering, University of California at Riverside, 900 University Avenue, Riverside, CA 92521, USA.

Isopeptidase activity of proteases plays critical roles in physiological and pathological processes in living organisms, such as protein stability in cancers and protein activity in infectious diseases. However, the kinetics of protease isopeptidase activity has not been explored before due to a lack of methodology. Here, we report the development of novel qFRET-based protease assay for characterizing the isopeptidase kinetics of SENP1.

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Real-world NOx emissions from heavy-duty diesel, natural gas, and diesel hybrid electric vehicles of different vocations on California roadways.

Sci Total Environ

August 2021

University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA 92507, USA; Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, CA 92521, USA. Electronic address:

This study assessed the real-world nitrogen oxide (NOx) emissions from 50 heavy-duty vehicles of different vocations and engine technologies using portable emissions measurement systems (PEMS). This is one of the most comprehensive in-use emissions studies conducted to date, which played a key role in the development of CARB's (California Air Recourses Board) updated EMission FACtor (EMFAC) model, especially for natural gas vehicles. In-use emissions testing was performed on school and transit buses, refuse haulers, goods movement vehicles, and delivery vehicles while were driven over their normal operating routes in the South Coast Air Basin.

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The structural complexity and robust intermolecular interactions have challenged the incorporation of technical lignin into value-added polymeric materials for decades. To study the correlation between lignin molecular structure and material properties of lignin-based polyurethanes, we applied co-solvent enhanced lignocellulosic fractionation pretreatment followed by sequential precipitation to produce three distinct lignin preparations with narrowly distributed (molecular weight dispersity <2) and comparatively low molecular weight (<1500 g/mol) from poplar biomass. Structural characterization indicated that these lignin preparations differed in average molecular chain length and stiffness as well as hydroxyl group distribution.

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Western Blotting of Membrane-Bound Proteins in Yarrowia lipolytica.

Methods Mol Biol

August 2021

Chemical and Environmental Engineering, University of California Riverside, Riverside, CA, USA.

With the discovery of Western blotting as first described by Towbin et al. in 1979, the transfer and visualization of electrophoretically separated proteins on membranes has become the de facto method for the qualitative and quantitative detection of proteins of interest. In this method, proteins are resolved by electrophoresis on a polyacrylamide gel, followed by a transfer of the separated proteins onto a nitrocellulose or polyvinyl difluoride (PVDF) membrane.

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Guide RNA Design for Genome-Wide CRISPR Screens in Yarrowia lipolytica.

Methods Mol Biol

August 2021

Chemical and Environmental Engineering, University of California Riverside, Riverside, CA, USA.

Genome-wide functional genomic screens are essential to determining the genetic underpinning of a biological process. Novel and powerful tools for perturbing gene function, with the help of genetic and epigenetic information, have made it possible to systematically investigate the contribution of every gene to evolved and engineered phenotypes. Functional genomics and screening for enhanced phenotypes become ever more important when dealing with nonconventional hosts.

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Effects of driving conditions on secondary aerosol formation from a GDI vehicle using an oxidation flow reactor.

Environ Pollut

August 2021

University of California, Bourns College of Engineering, Center for Environmental Research and Technology (CE-CERT), 1084 Columbia Avenue, Riverside, CA, 92507, USA. Electronic address:

A comprehensive study on the effects of photochemical aging on exhaust emissions from a vehicle equipped with a gasoline direct injection engine when operated over seven different driving cycles was assessed using an oxidation flow reactor. Both primary emissions and secondary aerosol production were measured over the Federal Test Procedure (FTP), LA92, New European Driving Cycle (NEDC), US06, and the Highway Fuel Economy Test (HWFET), as well as over two real-world cycles developed by the California Department of Transportation (Caltrans) mimicking typical highway driving conditions. We showed that the emissions of primary particles were largely depended on cold-start conditions and acceleration events.

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THF co-solvent pretreatment prevents lignin redeposition from interfering with enzymes yielding prolonged cellulase activity.

Biotechnol Biofuels

March 2021

Department of Chemical and Environmental Engineering, Bourns College of Engineering, University of California, Riverside, 900 University Ave, Riverside, CA, 92521, USA.

Background: Conventional aqueous dilute sulfuric acid (DSA) pretreatment of lignocellulosic biomass facilitates hemicellulose solubilization and can improve subsequent enzymatic digestibility of cellulose to fermentable glucose. However, much of the lignin after DSA pretreatment either remains intact within the cell wall or readily redeposits back onto the biomass surface. This redeposited lignin has been shown to reduce enzyme activity and contribute to rapid enzyme deactivation, thus, necessitating significantly higher enzyme loadings than deemed economical for biofuel production from biomass.

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Background: There are few effective therapies for coronavirus disease 2019 (COVID-19) upon the outbreak of the pandemic. To compare the effectiveness of a novel genetically engineered recombinant super-compound interferon (rSIFN-co) with traditional interferon-alpha added to baseline antiviral agents (lopinavir-ritonavir or umifenovir) for the treatment of moderate-to-severe COVID-19.

Method: In this multicenter randomized (1:1) trial, patients hospitalized with moderate-to-severe COVID-19 received either rSIFN-co nebulization or interferon-alpha nebulization added to baseline antiviral agents for no more than 28 days.

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Aims: Mineralization of crystalline particles and the formation of renal calculi contribute to the pathogenesis of crystal nephropathies. Several recent studies on the biology of crystal handling implicated intrarenal crystal deposition-induced necroinflammation in their pathogenesis. We hypothesized that 6,7-dihydroxycoumarin (DHC) inhibit intrarenal crystal cytotoxicity and necroinflammation, and ameliorate crystal-induced chronic kidney disease (CKD).

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Brain network dynamics fingerprints are resilient to data heterogeneity.

J Neural Eng

December 2020

Computational Neuroscience Laboratories, Advanced Telecommunications Research Institute International, 2-2-2 Hikaridai, Seika-cho, Soraku-gun, Kyoto, 619-0288, JAPAN.

Context: Large multi-site neuroimaging datasets have significantly advanced our quest to understand brain-behavior relationships and to develop biomarkers of psychiatric and neurodegenerative disorders. Yet, such data collections come at a cost, as the inevitable differences across samples may lead to biased or erroneous conclusions.

Objective: We aim to validate the estimation of individual brain network dynamics fingerprints and appraise sources of variability in large resting-state functional magnetic resonance imaging (rs-fMRI) datasets by providing a novel point of view based on data-driven dynamical models.

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Strong electric field tuning of magnetism in self-biased multiferroic structures.

Sci Rep

December 2020

Department of Mechanical and Aerospace Engineering, University of California, Los Angeles, CA, 90095, USA.

A new type of multiferroic heterostructure has been proposed in this work with strong electric field tuning of magnetism. It is composed of a self-biased magnetic layered structure with perpendicular magnetic anisotropy (PMA) and one piezoelectric substrate. Two configurations were investigated by a modeling approach, Ni/Ni/Ni/PMN-PT with Cu as spacer and Terfenol-D/CoFeB/Ni/PMN-PT.

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