13 results on '"Hancock, Matthew"'
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2. Simulated biological fluid exposure changes nanoceria's surface properties but not its biological response.
- Author
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Yokel, Robert A., Hancock, Matthew L., Cherian, Benjamin, Brooks, Alexandra J., Ensor, Marsha L., Vekaria, Hemendra J., Sullivan, Patrick G., and Grulke, Eric A.
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SURFACE properties , *CRYSTAL morphology , *BODY fluids , *CRYSTAL surfaces , *OXYGEN consumption - Abstract
Nanoscale cerium dioxide (nanoceria) has industrial applications, capitalizing on its catalytic, abrasive, and energy storage properties. It auto-catalytically cycles between Ce3+ and Ce4+, giving it pro-and anti-oxidative properties. The latter mediates beneficial effects in models of diseases that have oxidative stress/inflammation components. Engineered nanoparticles become coated after body fluid exposure, creating a corona, which can greatly influence their fate and effects. Very little has been reported about nanoceria surface changes and biological effects after pulmonary or gastrointestinal fluid exposure. The study objective was to address the hypothesis that simulated biological fluid (SBF) exposure changes nanoceria's surface properties and biological activity. This was investigated by measuring the physicochemical properties of nanoceria with a citric acid coating (size; morphology; crystal structure; surface elemental composition, charge, and functional groups; and weight) before and after exposure to simulated lung, gastric, and intestinal fluids. SBF-exposed nanoceria biological effect was assessed as A549 or Caco-2 cell resazurin metabolism and mitochondrial oxygen consumption rate. SBF exposure resulted in loss or overcoating of nanoceria's surface citrate, greater nanoceria agglomeration, deposition of some SBF components on nanoceria's surface, and small changes in its zeta potential. The engineered nanoceria and SBF-exposed nanoceria produced no statistically significant changes in cell viability or cellular oxygen consumption rates. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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3. WaveAR: A software tool for calculating parameters for water waves with incident and reflected components
- Author
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Landry, Blake J., Hancock, Matthew J., Mei, Chiang C., and García, Marcelo H.
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COMPUTER software , *WATER waves , *CRESTS (Hydrology) , *LITTORAL zone , *STOKES flow , *WAVE analysis , *NONLINEAR waves , *THEORY of wave motion - Abstract
Abstract: The ability to determine wave heights and phases along a spatial domain is vital to understanding a wide range of littoral processes. The software tool presented here employs established Stokes wave theory and sampling methods to calculate parameters for the incident and reflected components of a field of weakly nonlinear waves, monochromatic at first order in wave slope and propagating in one horizontal dimension. The software calculates wave parameters over an entire wave tank and accounts for reflection, weak nonlinearity, and a free second harmonic. Currently, no publicly available program has such functionality. The included MATLAB®-based open source code has also been compiled for Windows®, Mac® and Linux® operating systems. An additional companion program, VirtualWave, is included to generate virtual wave fields for WaveAR. Together, the programs serve as ideal analysis and teaching tools for laboratory water wave systems. [Copyright &y& Elsevier]
- Published
- 2012
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4. Biomimetic tissues on a chip for drug discovery
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Ghaemmaghami, Amir M., Hancock, Matthew J., Harrington, Helen, Kaji, Hirokazu, and Khademhosseini, Ali
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DRUG development , *BIOMIMETIC chemicals , *MEDICAL model , *TISSUE engineering , *BIOMATERIALS , *MICROFLUIDICS - Abstract
Developing biologically relevant models of human tissues and organs is an important enabling step for disease modeling and drug discovery. Recent advances in tissue engineering, biomaterials and microfluidics have led to the development of microscale functional units of such models also referred to as ‘organs on a chip’. In this review, we provide an overview of key enabling technologies and highlight the wealth of recent work regarding on-chip tissue models. In addition, we discuss the current challenges and future directions of organ-on-chip development. [ABSTRACT FROM AUTHOR]
- Published
- 2012
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5. Anisotropic material synthesis by capillary flow in a fluid stripe
- Author
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Hancock, Matthew J., Piraino, Francesco, Camci-Unal, Gulden, Rasponi, Marco, and Khademhosseini, Ali
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BIOMEDICAL materials , *ANISOTROPY , *CAPILLARITY , *VISCOSITY , *SURFACE tension , *BIOPOLYMERS , *MICROFLUIDICS , *COMPOSITE materials - Abstract
Abstract: We present a simple bench-top technique to produce centimeter long concentration gradients in biomaterials incorporating soluble, material, and particle gradients. By patterning hydrophilic regions on a substrate, a stripe of prepolymer solution is held in place on a glass slide by a hydrophobic boundary. Adding a droplet to one end of this “pre-wet” stripe causes a rapid capillary flow that spreads the droplet along the stripe to generate a gradient in the relative concentrations of the droplet and pre-wet solutions. The gradient length and shape are controlled by the pre-wet and droplet volumes, stripe thickness, fluid viscosity and surface tension. Gradient biomaterials are produced by crosslinking gradients of prepolymer solutions. Demonstrated examples include a concentration gradient of cells encapsulated in three dimensions (3D) within a homogeneous biopolymer and a constant concentration of cells encapsulated in 3D within a biomaterial gradient exhibiting a gradient in cell spreading. The technique employs coated glass slides that may be purchased or custom made from tape and hydrophobic spray. The approach is accessible to virtually any researcher or student and should dramatically reduce the time required to synthesize a wide range of gradient biomaterials. Moreover, since the technique employs passive mechanisms it is ideal for remote or resource poor settings. [Copyright &y& Elsevier]
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- 2011
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6. Convection-driven generation of long-range material gradients
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Du, Yanan, Hancock, Matthew J., He, Jiankang, Villa-Uribe, Jose L., Wang, Ben, Cropek, Donald M., and Khademhosseini, Ali
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ANISOTROPY , *BIOMIMETIC chemicals , *BIOMOLECULES , *MICROFLUIDICS , *COMPOSITE materials , *POROUS materials - Abstract
Abstract: Natural materials exhibit anisotropy with variations in soluble factors, cell distribution, and matrix properties. The ability to recreate the heterogeneity of the natural materials is a major challenge for investigating cell–material interactions and for developing biomimetic materials. Here we present a generic fluidic approach using convection and alternating flow to rapidly generate multi-centimeter gradients of biomolecules, polymers, beads and cells and cross-gradients of two species in a microchannel. Accompanying theoretical estimates and simulations of gradient growth provide design criteria over a range of material properties. A poly(ethylene-glycol) hydrogel gradient, a porous collagen gradient and a composite material with a hyaluronic acid/gelatin cross-gradient were generated with continuous variations in material properties and in their ability to regulate cellular response. This simple yet generic fluidic platform should prove useful for creating anisotropic biomimetic materials and high-throughput platforms for investigating cell–microenvironment interactions. [Copyright &y& Elsevier]
- Published
- 2010
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7. The conversion of an aziridine plus a phenyl-substituted amine oxide or aminoether to a benzodiazepine derivative
- Author
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Hancock, Matthew T., Minto, Robert E., and Pinhas, Allan R.
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AZIDES , *CARBONYL compounds , *METAL complexes , *ETHERS , *AMINES - Abstract
The conversion of an aziridine to a tetrahydrobenzodiazepine derivative using LiI, an iron carbonyl complex, and an amine oxide, or using LiI and a gem-aminoether is studied. The reaction of an aziridine with LiI and a phenyl-substituted iminium salt generates mainly a 1,2-diamine. The addition of t-butoxide to the iminium reaction changes the product ratio leading to a diamine as the minor product and a benzodiazepine as the major product. The structure proof of the tetrahydrobenzodiazepine derivative and the mechanism of these transformations are discussed. [Copyright &y& Elsevier]
- Published
- 2003
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8. The conversion of an aziridine plus an iminium salt to a 1,2-diamine
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Hancock, Matthew T. and Pinhas, Allan R.
- Subjects
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STEREOCHEMISTRY , *CHEMICAL bonds , *CHEMISTRY - Abstract
The conversion of an aziridine to a 1,2-diamine using lithium iodide and an iminium salt is discussed. We have found that when the aziridine is substituted by only alkyl groups, it is the less substituted carbon&z.sbnd;nitrogen bond that is broken; whereas, when the aziridine is substituted by a phenyl group at either the nitrogen or the carbon, it is the more substituted carbon&z.sbnd;nitrogen bond that is broken. For a 2,3-disubstituted aziridine, the reaction sequence goes with net retention of stereochemistry. [Copyright &y& Elsevier]
- Published
- 2003
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9. A convenient and inexpensive conversion of an aziridine to an oxazolidinone
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Hancock, Matthew T. and Pinhas, Allan R.
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IODIDES , *STEREOCHEMISTRY - Abstract
The conversion of an aziridine to the corresponding oxazolidinone using only carbon dioxide and a catalytic amount of lithium iodide is discussed. In all cases, either no reaction occurred or a high yield of product was obtained. HMPA has been added to the reaction mixture, as needed, to drastically improve the regioselectivity. Net retention of stereochemistry between the starting aziridine and the product oxazolidinone was observed. [Copyright &y& Elsevier]
- Published
- 2003
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10. The characterization of purified citrate-coated cerium oxide nanoparticles prepared via hydrothermal synthesis.
- Author
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Hancock, Matthew L., Yokel, Robert A., Beck, Matthew J., Calahan, Julie L., Jarrells, Travis W., Munson, Eric J., Olaniyan, George A., and Grulke, Eric A.
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CERIUM oxides , *HYDROTHERMAL synthesis , *CITRATES , *ELECTRON energy loss spectroscopy , *NANOPARTICLES , *NUCLEAR magnetic resonance spectroscopy , *CITRIC acid - Abstract
• Cerium ions, known to produce adverse biological effects, are removed by dialysis. • Characterization of citrate-coated nanoceria prepared via hydrothermal synthesis. • Results include size and morphology, surface composition, and crystallinity. • Investigation of the ceria-citrate complexation bonding structures. Cerium oxide nanoparticles were synthesized using a hydrothermal approach with citric acid as a stabilizing agent. Citric acid adsorption onto the nanoceria particle surface can cease particle formation and create a stable dispersion for an extended shelf life. The product was dialyzed immediately following the synthesis to remove unreacted cerium that could contribute to biological effects. Nanoparticle characterization results are expected to help identify the surface citrate bonding structure. Many characterization techniques were utilized to determine size, morphology, surface properties, and citrate complexation on the nanoceria particle surface. These included transmission electron microscopy, electron energy loss spectroscopy, dynamic light scattering, x-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, Raman spectroscopy, UV–Vis absorption spectroscopy, zeta potential, and 13C solid-state nuclear magnetic resonance spectroscopy. Primary particles were hexagonal, determined to be 4.2 nm in diameter. The hydrodynamic diameter of the dialyzed product was 10.8 nm. Each agglomerate was estimated to contain an average of 5.7 particles. The citrate coating contained 2.8 citrate molecules/nm2, corresponding to an approximate citrate monolayer. Citrate complexation with the nanoceria surface includes the central carboxyl geminal to the hydroxyl and perhaps one of its terminal carboxyl groups. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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11. 193 - Nox4 Regulates Exercise Performance and Cardiac Function During Acute Exercise in Mice.
- Author
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Hancock, Matthew, Catibog, Norman, Nabeebaccus, Adam A, Brandes, Ralf P, Schroder, Katrin, Shah, Ajay M, and Zhang, Min
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HEART physiology , *EXERCISE , *LABORATORY mice , *GENETIC regulation , *PERFORMANCE evaluation - Published
- 2015
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12. An artificial vasculature for adaptive thermal control of windows.
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Hatton, Benjamin D., Wheeldon, Ian, Hancock, Matthew J., Kolle, Mathias, Aizenberg, Joanna, and Ingber, Donald E.
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ENERGY consumption of buildings , *WINDOWS , *HEAT radiation & absorption , *HEATING , *PHOTOVOLTAIC cells , *MICROFABRICATION - Abstract
Windows are a major source of energy inefficiency in buildings. In addition, heating by thermal radiation reduces the efficiency of photovoltaic panels. To help reduce heating by solar absorption in both of these cases, we developed a thin, transparent, bio-inspired, convective cooling layer for building windows and solar panels that contains microvasculature with millimeter-scale, fluid-filled channels. The thin cooling layer is composed of optically clear silicone rubber with microchannels fabricated using microfluidic engineering principles. Infrared imaging was used to measure cooling rates as a function of flow rate and water temperature. In these experiments, flowing room temperature water at 2mL/min reduced the average temperature of a model 10×10cm2 window by approximately 7–9°C. An analytic steady-state heat transfer model was developed to augment the experiments and make more general estimates as functions of window size, channel geometry, flow rate, and water temperature. Thin cooling layers may be added to one or more panes in multi-pane windows or as thin film non-structural central layers. Lastly, the color, optical transparency and aesthetics of the windows could be modulated by flowing different fluids that differ in their scattering or absorption properties. [ABSTRACT FROM AUTHOR]
- Published
- 2013
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13. The phenotype of a flavin-containing monooyxgenase knockout mouse implicates the drug-metabolizing enzyme FMO1 as a novel regulator of energy balance.
- Author
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Veeravalli, Sunil, Omar, Bilal A., Houseman, Lyndsey, Hancock, Matthew, Gonzalez Malagon, Sandra G., Scott, Flora, Janmohamed, Azara, Phillips, Ian R., and Shephard, Elizabeth A.
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PHENOTYPES , *FLAVINS , *MONOOXYGENASES , *DRUG metabolism , *BIOENERGETICS , *LABORATORY mice - Abstract
Abstract: Flavin-containing monooxygenases (FMOs) of mammals are thought to be involved exclusively in the metabolism of foreign chemicals. Here, we report the unexpected finding that mice lacking Fmos 1, 2 and 4 exhibit a lean phenotype and, despite similar food intake, weigh less and store less triglyceride in white adipose tissue (WAT) than wild-type mice. This is a consequence of enhanced whole-body energy expenditure, due mostly to increased resting energy expenditure (REE). This is fuelled, in part, by increased fatty acid β-oxidation in skeletal muscle, which would contribute to depletion of lipid stores in WAT. The enhanced energy expenditure is attributed, in part, to an increased capacity for exercise. There is no evidence that the enhanced REE is due to increased adaptive thermogenesis; instead, our results are consistent with the operation in WAT of a futile energy cycle. In contrast to FMO2 and FMO4, FMO1 is highly expressed in metabolic tissues, including liver, kidney, WAT and BAT. This and other evidence implicates FMO1 as underlying the phenotype. The identification of a novel, previously unsuspected, role for FMO1 as a regulator of energy homeostasis establishes, for the first time, a role for a mammalian FMO in endogenous metabolism. Thus, FMO1 can no longer be considered to function exclusively as a xenobiotic-metabolizing enzyme. Consequently, chronic administration of drugs that are substrates for FMO1 would be expected to affect energy homeostasis, via competition for endogenous substrates, and, thus, have important implications for the general health of patients and their response to drug therapy. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
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