A5091378871- Silk-based biomaterials and applications
- Lignin and Wood Chemistry
- Plant biochemistry and biosynthesis
- Advanced NMR Techniques and Applications
- Biofuel production and bioconversion
- Biochemical and Structural Characterization
- Silkworms and Sericulture Research
- Fermentation and Sensory Analysis
- CO2 Reduction Techniques and Catalysts
- Surface Modification and Superhydrophobicity
- Magnetic and Electromagnetic Effects
- Microbial Natural Products and Biosynthesis
- Bioactive Natural Diterpenoids Research
- X-ray Diffraction in Crystallography
- Molecular Sensors and Ion Detection
- Microbial Fuel Cells and Bioremediation
- Biochemical and biochemical processes
- Insect and Arachnid Ecology and Behavior
- Natural product bioactivities and synthesis
- Photochromic and Fluorescence Chemistry
- Sesquiterpenes and Asteraceae Studies
- biodegradable polymer synthesis and properties
- Neurobiology and Insect Physiology Research
- Polymer composites and self-healing
- Phytochemical compounds biological activities
National Renewable Energy Laboratory
2020-2025
University of California, Davis
2016-2023
San Diego State University
2017-2021
Resonance Research (United States)
2011-2019
Arizona State University
2011-2016
Tempe Union High School District
2014
Utah State University
2014
Plant secondary cell walls (SCWs) are composed of a heterogeneous interplay three major biopolymers: cellulose, hemicelluloses, and lignin. Details regarding specific intermolecular interactions higher-order architecture the SCW superstructure remain ambiguous. Here, we use solid-state nuclear magnetic resonance (ssNMR) measurements to infer refined details about structural configuration, interactions, relative proximity all biopolymers within air-dried
In this paper, we study the kinetics of polyvinyl chloride (PVC) decomposition using a combination experimental and computational approaches. We develop simplified kinetic model that contains only two steps: dehydrochlorination PVC further residue. The is consistent with density functional theory (DFT) calculations data. Dehydrochlorination an autocatalytic reaction starts tertiary (Cl) generates hydrogen (HCl) benzene as main products. Benzene HCl formation rates showed similar trends,...
Terpenoids are a major component of maize (Zea mays) chemical defenses that mediate responses to herbivores, pathogens, and other environmental challenges. Here, we describe the biosynthesis elicited production class diterpenoids, named dolabralexins. Dolabralexin involves sequential activity two diterpene synthases, ENT-COPALYL DIPHOSPHATE SYNTHASE (ZmAN2) KAURENE SYNTHASE-LIKE4 (ZmKSL4). Together, ZmAN2 ZmKSL4 form hydrocarbon dolabradiene. In addition, biochemically characterized...
The adhesion and migration of cells entrapped in engineered materials is regulated by available adhesive ligands. Although mesenchymal stem cell (MSC) spheroids injected into damaged tissues promote repair, their transplantation biomaterials which regulate from the aggregate may further enhance therapeutic potential. Alginate hydrogels were modified with Arginine-Glycine-Aspartic acid (RGD) at increasing concentrations, osteogenically induced human MSC to assess migration, survival,...
Many natural silks produced by spiders and insects are unique materials in their exceptional toughness tensile strength, while being lightweight biodegradable-properties that currently unparalleled synthetic materials. Myriad approaches have been attempted to prepare artificial from recombinant spider silk spidroins but each failed achieve the advantageous properties of material. This is because an incomplete understanding vivo spidroin-to-fiber spinning process and, particularly, a lack...
Cross-linked elastomers are stretchable materials that typically not recyclable or biodegradable. Medium-chain-length polyhydroxyalkanoates (mcl-PHAs) soft and ductile, making these bio-based polymers good candidates for biodegradable elastomers. Elasticity is commonly imparted by a cross-linked network structure, covalent adaptable networks have emerged as solution to prepare thermosets via triggered rearrangement of dynamic bonds. Here, we develop chemically installing the within...
Adhesive silks spun by aquatic caddisfly (order Trichoptera) larvae are used to build both intricate protective shelters and food harvesting nets underwater. In this study, we use (13)C (31)P solid-state NMR wide angle X-ray diffraction (WAXD) as tools elucidate molecular protein structure of larval silk from the species Hesperophylax consimilis . Caddisfly is a fibroin based biopolymer containing mostly repetitive amino acid motifs. results provide strong supporting evidence for structural...
Abstract The two Flag/MaSp 2 silk proteins produced recombinantly were based on the basic consensus repeat of dragline spidroin protein (MaSp 2) from Nephila clavipes orb weaving spider. However, proline‐containing pentapeptides juxtaposed to polyalanine segments resembled those found in flagelliform (Flag) composing web spiral: (GPGGX 1 GPGGX ) with X /X = A/A or Y/S. Fibers formed films aqueous solutions extruded resolubilized dopes organic conditions when Flag motif was Y/S A/A,...
Spider silk has exceptional mechanical and biocompatibility properties. The goal of this study was optimization the properties synthetic spider thin films made from forms MaSp1 MaSp2, which compose dragline Nephila clavipes. We increased stress 2 solubilized in both HFIP water by adding glutaraldehyde then stretching them an alcohol based stretch bath. This resulted stresses as high 206 MPa elongations up to 35%, is 4× higher than as-poured controls. Films were analyzed using NMR, XRD,...
Metal carbenes appended with two electron-donating groups, known as "donor/donor" carbenes, undergo diastereo- and enantioselective rhodium-catalyzed C-H insertion reactions ether substrates to form benzodihydrofurans. Unlike the of metal electron-withdrawing groups attached, attenuated electrophilicity enables these be conducted in Lewis basic solvents (e.g., acetonitrile) presence water. The diazo precursors for species are prepared situ from hydrazone using a mild chemoselective oxidant...
Diterpenoids constitute a diverse class of metabolites with critical functions in plant development, defense, and ecological adaptation. Major monocot crops, such as maize (Zea mays) rice (Oryza sativa), deploy blends specialized diterpenoids core components biotic abiotic stress resilience. Here, we describe the genome-wide identification functional characterization stress-related diterpene synthases (diTPSs) dedicated bioenergy crop switchgrass (Panicum virgatum). Mining allotetraploid...
Numerous monomeric and oligomeric flavanol sulfonation products were observed in 10 wines. Levels of 0.85-20.06 0-14.72 mg/L quantified for two sulfonated flavan-3-ols and, surprisingly, generally higher than the well-known native flavan-3-ol monomers. Increasing SO2 levels during wine aging increased sulfonate-modified monomers dimers along with concentrations The results indicate that >10% is reacting C-4 carbocation, formed from acid cleavage interflavan bond, perhaps by a bimolecular...
Abstract Background Multiple analytical methods have been developed to determine the ratios of aromatic lignin units, particularly syringyl/guaiacyl (S/G) ratio, biopolymers in plant cell walls. Chemical degradation such as thioacidolysis produce units that are released from certain linkages and may induce chemical changes rendering it difficult distinguish source specific released, is case with nitrobenzene oxidation methodology. NMR provide powerful tools used analyze walls for composition...
An integrated photoelectrochemical architecture, with cyanobacteria lacking photosystem II activity, uses photons and exogenous electrons to convert carbon dioxide into fuel products.
Abstract Low‐density polyethylene (LDPE) is ubiquitous in the packaging industry owing to its flexibility, toughness, and low cost. However, it typically contaminated with other materials, seriously limiting options for mechanical recycling. Interest chemical recycling techniques such as pyrolysis hydrothermal liquefaction growing, but most of these processes face technoeconomic challenges that have limited commercial deployment. This study concerns a hybrid chemomechanical approach using...
Nuclear magnetic resonance (NMR) and X-ray diffraction (XRD) experiments reveal the structural importance of divalent cation-phosphate complexes in formation β-sheet nanocrystals from phosphorylated serine-rich regions within aquatic silk caddisfly larvae species Hesperophyla consimilis. Wide angle XRD data on native show that contains a significant crystalline component with repetitive orthorhombic unit cell aligned along fiber axis dimensions 5.9 Å × 23.2 17.3 Å. These nanocrystalline...
Insects of the order Embioptera, known as embiopterans, embiids, or webspinners, weave silk fibers together into sheets to make shelters called galleries. In this study, we show that galleries produced by embiopteran Antipaluria urichi exhibit a highly hydrophobic wetting state with high water adhesion macroscopically equivalent rose petal effect. Specifically, have advancing contact angles above 150°, but receding angle approaching 0°. The consist layered fiber bundles single strands spaced...
Abstract Prey wrapping spider silk's unique mechanical properties are investigated confirming the high degree of extensibility and superior toughness compared to other types silk. For first time, pre‐spinning dope phase is studied in isotope‐enriched intact aciniform (AC) silk glands using solution NMR that reveals a combination α‐helical domains linked by disordered random coil chains consistent with previously proposed “beads‐on‐a‐string” models. The model further refined through...
Large composite structures, such as those used in wind energy applications, rely on the bulk polymerization of thermosets an impressively large scale. To accomplish this, traditional thermoset polymerizations require both elevated temperatures (>100 °C) and extended cure durations (>5 h) for complete conversion, necessitating use oversize ovens or heated molds. In turn, these requirements lead to energy-intensive polymerizations, incurring high manufacturing costs process emissions. this...
In this work, we present a novel rapid method for fabricating biocompatible, biodegradable gold nanoparticle-embedded silk films (AuNP–silk films) that have potential applications in bioengineering and biomedical research.
Plants produce an immense diversity of natural products (i.e. secondary or specialized metabolites) that offer a rich source known and potentially new pharmaceuticals other desirable bioproducts. The Traditional Chinese Medicinal plant Isodon rubescens (Lamiaceae) contains array bioactive labdane-related diterpenoid products. Of these, the ent-kauranoid oridonin is most prominent metabolite has been extensively studied for its potent antimicrobial anticancer efficacy. Mining previously...
Abstract A simple and highly selective analytical procedure is presented for the determination of cellulosic glucan content in samples that contain both cellulose starch. This method eliminates unacceptably large compounding errors current two-measurement methods. If starch are present before hydrolysis, will be hydrolyzed to glucose causing bias inaccuracy method. To prevent this interference, removal prior quantification crucial. The here a concise in-series with minimal measurements,...