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De Henau R, de Vries A, Rousseau D. Structure and mechanical properties of anisotropic agar gels obtained via unidirectional freezing. Food Res Int 2024; 191:114626. [PMID: 39059897 DOI: 10.1016/j.foodres.2024.114626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 06/06/2024] [Accepted: 06/06/2024] [Indexed: 07/28/2024]
Abstract
The controllable formation of anisotropic gel structures is presently sought for the development of foods with novel textures. Here, we used unidirectional freezing to generate agar gels consisting of a honeycomb-like porous network of elongated and aligned pores. A custom-built Peltier system allowed for control of the freezing front velocity throughout the agar gels. A higher freezing velocity (10 µm/s) led to smaller pore sizes compared to the slower freezing velocity tested (2 µm/s). Texture analysis highlighted the significantly higher Young's modulus in the gels when compressed in the axial vs. radial direction - a direct consequence of the unidirectional freezing. The proton spin-spin relaxation time revealed greater water mobility in the unidirectionally frozen gel with larger pores. This study serves as the basis for the development of anisotropic hydrocolloid gels with a tunable microstructure and texture.
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Affiliation(s)
- Raphaël De Henau
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Canada
| | - Auke de Vries
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Canada; New School Foods, Toronto, Canada
| | - Dérick Rousseau
- Department of Chemistry and Biology, Toronto Metropolitan University, Toronto, Canada.
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Ogata K, Hashizume M, Takahashi R, Hamaguchi T, Jinnai H, Yusa SI. Formation of Polyion Complex Aggregate Formed from a Cationic Block Copolymer and Anionic Polysaccharide. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:16484-16493. [PMID: 37947780 DOI: 10.1021/acs.langmuir.3c02404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Block copolymers (PmMn; P20M101 and P100M98) comprising poly(2-(methacryloyloxy)ethylphosphorylcholine) (PMPC, P) containing biocompatible phosphorylcholin pendants and cationic poly((3-acryloylaminopropyl) trimethylammonium chloride) (PMAPTAC, M) were synthesized via a controlled radical polymerization method. The degrees of polymerization of the PMPC and PMAPTAC segments are denoted by subscripts (PmMn). The mixture of cationic PmMn and anionic sodium chondroitin sulfate C (CS) with the pendant anionic carboxylate and sulfonate groups formed polyion complex (PIC) aggregates in phosphate-buffered saline. A charge-neutralized mixture of P20M101 with CS formed P20M101/CS PIC vesicles with a hydrodynamic radius (Rh) of 97.2 nm, zeta potential of ca. 0 mV, and aggregation number (Nagg) of 23,044. PMPC shells covered the surface of the PIC vesicles. The mixture of P100M98 and CS formed PIC spherical micelles with the PIC core and hydrophilic PMPC shells. The Rh, zeta potential, and Nagg of the PIC micelles were 26.4 nm, ca. 0 mV, and 404, respectively. At pH < 4, the carboxylate anions in CS were protonated. Thus, the charge balance in the PIC micelles shifted to decrease the core density owing to the electrostatic repulsions of the excess cations in the core. The PIC micelles dissociated at a NaCl concentration ≥0.6 M owing to the charge screening effect. The positively charged PIC micelles with excess P100M98 can encapsulate anionic dyes owing to electrostatic interaction.
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Affiliation(s)
- Kazushi Ogata
- Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan
| | - Mineo Hashizume
- Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Rintaro Takahashi
- Department of Energy Engineering, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603, Japan
| | - Tasuku Hamaguchi
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Hiroshi Jinnai
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577, Japan
| | - Shin-Ichi Yusa
- Department of Applied Chemistry, Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan
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Lachowicz D, Kmita A, Gajewska M, Trynkiewicz E, Przybylski M, Russek SE, Stupic KF, Woodrum DA, Gorny KR, Celinski ZJ, Hankiewicz JH. Aqueous Dispersion of Manganese-Zinc Ferrite Nanoparticles Protected by PEG as a T 2 MRI Temperature Contrast Agent. Int J Mol Sci 2023; 24:16458. [PMID: 38003646 PMCID: PMC10671015 DOI: 10.3390/ijms242216458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 11/03/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023] Open
Abstract
Mixed manganese-zinc ferrite nanoparticles coated with PEG were studied for their potential usefulness in MRI thermometry as temperature-sensitive contrast agents. Particles in the form of an 8.5 nm core coated with a 3.5 nm layer of PEG were fabricated using a newly developed, one-step method. The composition of Mn0.48Zn0.46Fe2.06O4 was found to have a strong thermal dependence of magnetization in the temperature range between 5 and 50 °C. Nanoparticles suspended in an agar gel mimicking animal tissue and showing non-significant impact on cell viability in the biological test were studied with NMR and MRI over the same temperature range. For the concentration of 0.017 mg/mL of Fe, the spin-spin relaxation time T2 increased from 3.1 to 8.3 ms, while longitudinal relaxation time T1 shows a moderate decrease from 149.0 to 125.1 ms. A temperature map of the phantom exposed to the radial temperature gradient obtained by heating it with an 808 nm laser was calculated from T2 weighted spin-echo differential MR images. Analysis of temperature maps yields thermal/spatial resolution of 3.2 °C at the distance of 2.9 mm. The experimental relaxation rate R2 data of water protons were compared with those obtained from calculations using a theoretical model incorporating the motion averaging regime.
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Affiliation(s)
- Dorota Lachowicz
- Academic Centre for Materials and Nanotechnology, AGH University of Krakow, 30-059 Krakow, Poland; (D.L.); (M.G.); (E.T.); (M.P.)
| | - Angelika Kmita
- Academic Centre for Materials and Nanotechnology, AGH University of Krakow, 30-059 Krakow, Poland; (D.L.); (M.G.); (E.T.); (M.P.)
| | - Marta Gajewska
- Academic Centre for Materials and Nanotechnology, AGH University of Krakow, 30-059 Krakow, Poland; (D.L.); (M.G.); (E.T.); (M.P.)
| | - Elżbieta Trynkiewicz
- Academic Centre for Materials and Nanotechnology, AGH University of Krakow, 30-059 Krakow, Poland; (D.L.); (M.G.); (E.T.); (M.P.)
| | - Marek Przybylski
- Academic Centre for Materials and Nanotechnology, AGH University of Krakow, 30-059 Krakow, Poland; (D.L.); (M.G.); (E.T.); (M.P.)
- Faculty of Physics and Applied Computer Science, AGH University of Krakow, 30-059 Krakow, Poland
| | - Stephen E. Russek
- National Institute of Standards and Technology, 325 Broadway St, Boulder, CO 80305, USA; (S.E.R.)
| | - Karl F. Stupic
- National Institute of Standards and Technology, 325 Broadway St, Boulder, CO 80305, USA; (S.E.R.)
| | - David A. Woodrum
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA; (D.A.W.); (K.R.G.)
| | - Krzysztof R. Gorny
- Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA; (D.A.W.); (K.R.G.)
| | - Zbigniew J. Celinski
- Center for the BioFrontiers Institute, University of Colorado Colorado Springs, 1420 Austin Bluffs Parkway, Colorado Springs, CO 80918, USA; (Z.J.C.); (J.H.H.)
| | - Janusz H. Hankiewicz
- Center for the BioFrontiers Institute, University of Colorado Colorado Springs, 1420 Austin Bluffs Parkway, Colorado Springs, CO 80918, USA; (Z.J.C.); (J.H.H.)
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Roux DCD, Jeacomine I, Maîtrejean G, Caton F, Rinaudo M. Characterization of Agarose Gels in Solvent and Non-Solvent Media. Polymers (Basel) 2023; 15:polym15092162. [PMID: 37177308 PMCID: PMC10181322 DOI: 10.3390/polym15092162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 04/28/2023] [Accepted: 04/28/2023] [Indexed: 05/15/2023] Open
Abstract
Agarose is known to form a homogeneous thermoreversible gel in an aqueous medium over a critical polymer concentration. The solid-liquid phase transitions are thermoreversible but depend on the molecular structure of the agarose sample tested. The literature has mentioned that agarose gels could remain stable in non-solvents such as acetone or ethanol. However, there has been no characterization of their behavior nor a comparison with the gels formed in a good solvent such as water. In the first step of this article, the structure was characterized using 1H and 13C NMR in both D2O and DMSO-d6 solvents. DMSO is a solvent that dissolves agarose regardless of the temperature. First, we have determined a low yield of methyl substitution on the D-galactose unit. Then, the evolution of the 1H NMR spectrum was monitored as a function of temperature during both increasing and decreasing temperature processes, ranging from 25 to 80 °C. A large thermal hysteresis was obtained and discussed, which aided in the interpretation of rheological behavior. The hysteresis of NMR signals is related to the mobility of the agarose chains, which follows the sol/gel transition depending on the chains' association with H-bonds between water and the -OH groups of agarose for tightly bound water and agarose/agarose in chain packing. In the second step of the study, the water in the agarose gel was exchanged with ethanol, which is a non-solvent for agarose. The resulting gel was stable, and its properties were characterized using rheology and compared to its behavior in aqueous media. The bound water molecules that act as plasticizers were likely removed during the exchange process, resulting in a stronger and more brittle gel in ethanol, with higher thermal stability compared to the aqueous gel. It is the first time that such gel is characterized without phase transition when passing from a good solvent to a non-solvent. This extends the domains of application of agarose.
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Affiliation(s)
- Denis C D Roux
- Univ. Grenoble Alpes, CNRS, Grenoble INP (Institute of Engineering Univ. Grenoble Alpes), LRP, 38000 Grenoble, France
| | - Isabelle Jeacomine
- NMR Centers of RMN-ICMG (FR2607), CERMAV-CNRS, BP53, 38000 Grenoble, France
| | - Guillaume Maîtrejean
- Univ. Grenoble Alpes, CNRS, Grenoble INP (Institute of Engineering Univ. Grenoble Alpes), LRP, 38000 Grenoble, France
| | - François Caton
- Univ. Grenoble Alpes, CNRS, Grenoble INP (Institute of Engineering Univ. Grenoble Alpes), LRP, 38000 Grenoble, France
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Senzano LM, Bovo RP, Andrade DV. Empirical estimation of skin resistance to water loss in amphibians: agar evaluation as a non-resistance model to evaporation. J Exp Biol 2022; 225:276192. [PMID: 35818822 DOI: 10.1242/jeb.243941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 07/05/2022] [Indexed: 11/20/2022]
Abstract
Total resistance (RT) to evaporative water loss (EWL) in amphibians is given by the sum of the boundary layer (rb) and the skin resistance (rs). Thus, rs can be determined if the rb component is defined (rs=RT - rb). The use of agar models has become the standard technique to estimate rb under the assumption that agar surface imposes no barrier to evaporation (rs=0). We evaluated this assumption by determining EWL rates and rb values from exposed surfaces of free water, a physiological solution mimicking the osmotic properties of a generalized amphibian, and agar gels prepared at various concentrations either using water or physiological solution as diluent. Water evaporation was affected by both, the presence of solutes and agar concentration. Models prepared with agar at 5% concentration in water provided the most practical and appropriate proxy for the estimation of rb.
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Affiliation(s)
- Luis M Senzano
- Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil
| | - Rafael P Bovo
- Departmento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Denis V Andrade
- Departamento de Biodiversidade, Instituto de Biociências, Universidade Estadual Paulista, Rio Claro, São Paulo, Brazil
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Tracking oxidation-induced alterations in fibrin clot formation by NMR-based methods. Sci Rep 2021; 11:15691. [PMID: 34344919 PMCID: PMC8333047 DOI: 10.1038/s41598-021-94401-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 07/05/2021] [Indexed: 12/12/2022] Open
Abstract
Plasma fibrinogen is an important coagulation factor and susceptible to post-translational modification by oxidants. We have reported impairment of fibrin polymerization after exposure to hypochlorous acid (HOCl) and increased methionine oxidation of fibrinogen in severely injured trauma patients. Molecular dynamics suggests that methionine oxidation poses a mechanistic link between oxidative stress and coagulation through protofibril lateral aggregation by disruption of AαC domain structures. However, experimental evidence explaining how HOCl oxidation impairs fibrinogen structure and function has not been demonstrated. We utilized polymerization studies and two dimensional-nuclear magnetic resonance spectrometry (2D-NMR) to investigate the hypothesis that HOCl oxidation alters fibrinogen conformation and T2 relaxation time of water protons in the fibrin gels. We have demonstrated that both HOCl oxidation of purified fibrinogen and addition of HOCl-oxidized fibrinogen to plasma fibrinogen solution disrupted lateral aggregation of protofibrils similarly to competitive inhibition of fibrin polymerization using a recombinant AαC fragment (AαC 419–502). DOSY NMR measurement of fibrinogen protons demonstrated that the diffusion coefficient of fibrinogen increased by 17.4%, suggesting the oxidized fibrinogen was more compact and fast motion in the prefibrillar state. 2D-NMR analysis reflected that water protons existed as bulk water (T2) and intermediate water (T2i) in the control plasma fibrin. Bulk water T2 relaxation time was increased twofold and correlated positively with the level of HOCl oxidation. However, T2 relaxation of the oxidized plasma fibrin gels was dominated by intermediate water. Oxidation induced thinner fibers, in which less water is released into the bulk and water fraction in the hydration shell was increased. We have confirmed that T2 relaxation is affected by the self-assembly of fibers and stiffness of the plasma fibrin gel. We propose that water protons can serve as an NMR signature to probe oxidative rearrangement of the fibrin clot.
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Barucci A, Flori A, Carpi R, Marchi DD, Esposito M, Menichetti L, Pini R, Ratto F, Belli G, Piazza F. Ficoll as testing material for diffusion weighted imaging-quality assurance phantoms. Magn Reson Imaging 2020; 76:1-7. [PMID: 33161101 DOI: 10.1016/j.mri.2020.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 11/03/2020] [Accepted: 11/03/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE The aim of this work is to test the use of aqueous solutions of Ficoll®**, a highly branched polymer displaying crowding properties, to build a phantom suitable for Diffusion Weighted Imaging (DWI) in Magnetic Resonance Imaging (MRI). METHODS We developed a test object made of a cylindrical plastic container with a precise geometrical arrangement suitable for measuring several samples at the same time. The container was designed to host single vials with variable geometry and number, and to fit inside common commercial head coils for MRI scanners. In our experiments, vials were filled with 8 aqueous solutions of Ficoll 70 and Ficoll 400 spanning a range of polymer concentration from 5 to 30% by weight. Vials containing ultra-pure water were also used as reference. Experiments were performed on both 1.5 and 3 T clinical scanners (GE, Philips and Siemens), under the conditions of a standard clinical examination. RESULTS The geometry of the phantom provided reduced imaging artifacts, especially image distortions at magnetic interfaces. We found that the Apparent Diffusion Coefficient (ADC) varied in the range of 0.00125-0.00223 mm2/s and decreased with Ficoll concentration. ADC vs Ficoll concentration exhibited a linear trend. Results were consistent over time and among different MRI clinical scanners, showing an average variability of 3% at 1.5 T and of 7.5% at 3 T. Moreover, no substantial difference was found between Ficoll 70 and 400. By varying Ficoll concentration, ADC can be modulated to approach tissue-mimicking values. Preliminary results for relaxation measurements proved that both T1 and T2 decreased with Ficoll concentration in the ranges 1.3-2.4 s and 150-800 ms respectively. CONCLUSIONS In this work, we propose a 3D phantom design based on the widespread crowding agent Ficoll, which is suitable for DWI quality assurance purposes in MRI acquisitions. Aqueous Ficoll solutions provide good performance in terms of stability, ease of preparation, and safety.
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Affiliation(s)
- Andrea Barucci
- "Nello Carrara" Institute of Applied Physics, CNR Florence Research Area, Via Madonna del Piano 10, 50019 Sesto Fiorentino, FI, Italy.
| | - Alessandra Flori
- Bioengineering and clinical engineering unit, Fondazione CNR/Regione Toscana G. Monasterio, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Roberto Carpi
- USL Toscana Centro, Piazza Santa Maria Nuova 1, 50121 Firenze, Italy
| | - Daniele De Marchi
- MRI unit, Fondazione CNR/Regione Toscana G. Monasterio, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Marco Esposito
- USL Toscana Centro, Piazza Santa Maria Nuova 1, 50121 Firenze, Italy
| | - Luca Menichetti
- Institute of Clinical Physiology, CNR, Via G. Moruzzi 1, 56124 Pisa, Italy
| | - Roberto Pini
- "Nello Carrara" Institute of Applied Physics, CNR Florence Research Area, Via Madonna del Piano 10, 50019 Sesto Fiorentino, FI, Italy
| | - Fulvio Ratto
- "Nello Carrara" Institute of Applied Physics, CNR Florence Research Area, Via Madonna del Piano 10, 50019 Sesto Fiorentino, FI, Italy
| | - Giacomo Belli
- Health Physics Unit, AOU Careggi, Largo Brambilla 3, 50134 Firenze, Italy
| | - Francesco Piazza
- Université d'Orléans and Centre de Biophysique Moléculaire (CBM), CNRS UPR 4301, rue Charles Sadron, 45071 Orléans, France
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Pan H, Geysens P, Putzeys T, Gennaro A, Yi Y, Li H, Atkin R, Binnemans K, Luo J, Wübbenhorst M. Physicochemical study of diethylmethylammonium methanesulfonate under anhydrous conditions. J Chem Phys 2020; 152:234504. [PMID: 32571054 DOI: 10.1063/5.0011756] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The protic ionic liquid diethylmethylammonium methanesulfonate ([DEMA][OMs]) was analyzed in depth by differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, Raman spectroscopy, and broadband dielectric spectroscopy (BDS) under anhydrous conditions. Karl Fischer titration, NMR, and FT-IR spectra confirmed the high purity of [DEMA][OMs]. The melting point (37.7 °C) and the freezing point (14.0 °C) obtained by DSC agree well with the values determined by BDS (40.0 °C and 14.0 °C). The dc conductivity (σdc) above the melting/freezing point obeys the Vogel-Fulcher-Tammann (VFT) equation well, and thus, the proton conduction in [DEMA][OMs] is assumed to be dominated by the vehicle mechanism. In contrast, the σdc below the melting/freezing point can be fitted by the Arrhenius equation separately, and therefore, the proton conduction is most likely governed by the proton hopping mechanism. The non-negligible influence of previously reported low water content on the physicochemical properties of [DEMA][OMs] is found, indicating the importance of reducing water content as much as possible for the study of "intrinsic" properties of protic ionic liquids.
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Affiliation(s)
- Hailong Pan
- Laboratory for Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven, Leuven 3001, Belgium
| | - Pieter Geysens
- Department of Chemistry, KU Leuven, 3001 Leuven, Belgium
| | - Tristan Putzeys
- Laboratory for Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven, Leuven 3001, Belgium
| | - Alessia Gennaro
- Laboratory for Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven, Leuven 3001, Belgium
| | - Yingting Yi
- Laboratory for Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven, Leuven 3001, Belgium
| | - Hua Li
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Rob Atkin
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Koen Binnemans
- Department of Chemistry, KU Leuven, 3001 Leuven, Belgium
| | - Jiangshui Luo
- Laboratory for Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven, Leuven 3001, Belgium
| | - Michael Wübbenhorst
- Laboratory for Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven, Leuven 3001, Belgium
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Keren-Paz A, Kolodkin-Gal I. A brick in the wall: Discovering a novel mineral component of the biofilm extracellular matrix. N Biotechnol 2020; 56:9-15. [DOI: 10.1016/j.nbt.2019.11.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 11/01/2019] [Accepted: 11/02/2019] [Indexed: 01/09/2023]
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10
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Bertasa M, Poli T, Riedo C, Di Tullio V, Capitani D, Proietti N, Canevali C, Sansonetti A, Scalarone D. A study of non-bounded/bounded water and water mobility in different agar gels. Microchem J 2018. [DOI: 10.1016/j.microc.2018.03.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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11
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Keren-Paz A, Brumfeld V, Oppenheimer-Shaanan Y, Kolodkin-Gal I. Micro-CT X-ray imaging exposes structured diffusion barriers within biofilms. NPJ Biofilms Microbiomes 2018; 4:8. [PMID: 29675263 PMCID: PMC5904145 DOI: 10.1038/s41522-018-0051-8] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Revised: 03/05/2018] [Accepted: 03/20/2018] [Indexed: 11/09/2022] Open
Abstract
In nature, bacteria predominantly exist as highly structured biofilms, which are held together by extracellular polymeric substance and protect their residents from environmental insults, such as antibiotics. The mechanisms supporting this phenotypic resistance are poorly understood. Recently, we identified a new mechanism maintaining biofilms - an active production of calcite minerals. In this work, a high-resolution and robust µCT technique is used to study the mineralized areas within intact bacterial biofilms. µCT is a vital tool for visualizing bacterial communities that can provide insights into the relationship between bacterial biofilm structure and function. Our results imply that dense and structured calcium carbonate lamina forms a diffusion barrier sheltering the inner cell mass of the biofilm colony. Therefore, µCT can be employed in clinical settings to predict the permeability of the biofilms. It is demonstrated that chemical interference with urease, a key enzyme in biomineralization, inhibits the assembly of complex bacterial structures, prevents the formation of mineral diffusion barriers and increases biofilm permeability. Therefore, biomineralization enzymes emerge as novel therapeutic targets for highly resistant infections.
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Affiliation(s)
- Alona Keren-Paz
- 1Department of Molecular Genetics, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Vlad Brumfeld
- 2Chemical Research Support, Weizmann Institute of Science, 76100 Rehovot, Israel
| | | | - Ilana Kolodkin-Gal
- 1Department of Molecular Genetics, Weizmann Institute of Science, 76100 Rehovot, Israel
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12
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Marco-Rius I, Gordon JW, Mattis AN, Bok R, Santos RD, Sukumar S, Larson PE, Vigneron DB, Ohliger MA. Diffusion-weighted imaging of hyperpolarized [ 13 C]urea in mouse liver. J Magn Reson Imaging 2018; 47:141-151. [PMID: 28419644 PMCID: PMC5645231 DOI: 10.1002/jmri.25721] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 03/16/2017] [Indexed: 12/20/2022] Open
Abstract
PURPOSE To compare the apparent diffusion coefficient (ADC) of hyperpolarized (HP) [13 C,15 N]urea to the ADC of endogenous water in healthy and fibrotic mouse liver. MATERIALS AND METHODS ADC measurements for water and [13 C]urea were made in agarose phantoms at 14.1T. Next, the ADC of water and injected HP [13 C,15 N]urea were measured in eight CD1 mouse livers before and after induction of liver fibrosis using CCl4 . Liver fibrosis was quantified pathologically using the modified Brunt fibrosis score and compared to the measured ADC of water and urea. RESULTS In cell-free phantoms with 12.5% agarose, water ADC was nearly twice the ADC of urea (1.93 × 10-3 mm2 /s vs. 1.00 × 10-3 mm2 /s). The mean ADC values of water and [13 C,15 N]urea in healthy mouse liver (±SD) were nearly identical [(0.75 ± 0.11) × 10-3 mm2 /s and (0.75 ± 0.22) × 10-3 mm2 /s, respectively]. Mean water and [13 C,15 N]urea ADC values in fibrotic liver (±SD) were (0.84 ± 0.22) × 10-3 mm2 /s and (0.75 ± 0.15) × 10-3 mm2 /s, respectively. Neither water nor urea ADCs were statistically different in the fibrotic livers compared to baseline (P = 0.14 and P = 0.99, respectively). Water and urea ADCs were positively correlated at baseline (R2 = 0.52 and P = 0.045) but not in fibrotic livers (R2 = 0.23 and P = 0.23). CONCLUSION ADC of injected hyperpolarized urea in healthy liver reflects a smaller change as compared to free solution than ADC of water. This may reflect differences in cellular compartmentalization of the two compounds. No significant change in ADC of either water or urea were observed in relatively mild stages of liver fibrosis. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:141-151.
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Affiliation(s)
- Irene Marco-Rius
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Jeremy W. Gordon
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Aras N. Mattis
- Department of Pathology, University of California San Francisco, San Francisco, California, USA
- UCSF Liver Center University of California San Francisco, San Francisco, California, USA
| | - Robert Bok
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Romelyn Delos Santos
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Subramanian Sukumar
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Peder E.Z. Larson
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
| | - Daniel B. Vigneron
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
- UCSF Liver Center University of California San Francisco, San Francisco, California, USA
| | - Michael A. Ohliger
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA
- UCSF Liver Center University of California San Francisco, San Francisco, California, USA
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13
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Caccavo D, Cascone S, Poto S, Lamberti G, Barba AA. Mechanics and transport phenomena in agarose-based hydrogels studied by compression-relaxation tests. Carbohydr Polym 2017; 167:136-144. [DOI: 10.1016/j.carbpol.2017.03.027] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 02/26/2017] [Accepted: 03/08/2017] [Indexed: 12/22/2022]
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14
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Tenório RP, Barros W. Patterns in Saccharomyces cerevisiae yeast colonies via magnetic resonance imaging. Integr Biol (Camb) 2017; 9:68-75. [PMID: 27942686 DOI: 10.1039/c6ib00219f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We report the use of high-resolution magnetic resonance imaging methods to observe pattern formation in colonies of Saccharomyces cerevisiae. Our results indicate substantial signal loss localized in specific regions of the colony rendering useful imaging contrast. This imaging contrast is recognizable as being due to discontinuities in magnetic susceptibility (χ) between different spatial regions. At the microscopic pixel level, the local variations in the magnetic susceptibility (Δχ) induce a loss in the NMR signal, which was quantified via T2 and T2* maps, permitting estimation of Δχ values for different regions of the colony. Interestingly the typical petal/wrinkling patterns present in the colony have a high degree of correlation with the estimated susceptibility distribution. We conclude that the presence of magnetic susceptibility inclusions, together with their spatial arrangement within the colony, may be a potential cause of the susceptibility distribution and therefore the contrast observed on the images.
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Affiliation(s)
- Rômulo P Tenório
- Centro Regional de Ciências Nucleares do Nordeste, Comissão Nacional de Energia Nuclear, Av. Prof. Luiz Freire, 200, Cidade Universitária, 50740-540, Recife, Pernambuco, Brazil.
| | - Wilson Barros
- Departamento de Física, Universidade Federal de Pernambuco, Av. Prof. Luiz Freire, s/n, Cidade Universitária, 50670-901, Recife, Pernambuco, Brazil
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15
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Mao B, Divoux T, Snabre P. Impact of saccharides on the drying kinetics of agarose gels measured by in-situ interferometry. Sci Rep 2017; 7:41185. [PMID: 28112236 PMCID: PMC5253732 DOI: 10.1038/srep41185] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 12/15/2016] [Indexed: 12/17/2022] Open
Abstract
Agarose gels are viscoelastic soft solids that display a porous microstructure filled with water at 90% w/w or more. Despite an extensive use in food industry and microbiology, little is known about the drying kinetics of such squishy solids, which suffers from a lack of time-resolved local measurements. Moreover, only scattered empirical observations are available on the role of the gel composition on the drying kinetics. Here we study by in-situ interferometry the drying of agarose gels of various compositions cast in Petri dishes. The gel thinning is associated with the displacement of interference fringes that are analyzed using an efficient spatiotemporal filtering method, which allows us to assess local thinning rates as low as 10 nm/s with high accuracy. The gel thinning rate measured at the center of the dish appears as a robust observable to quantify the role of additives on the gel drying kinetics and compare the drying speed of agarose gels loaded with various non-gelling saccharides of increasing molecular weights. Our work shows that saccharides systematically decrease the agarose gel thinning rate up to a factor two, and exemplifies interferometry as a powerful tool to quantify the impact of additives on the drying kinetics of polymer gels.
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Affiliation(s)
- Bosi Mao
- Centre de Recherche Paul Pascal, CNRS UPR 8641 - 115 avenue Dr. Schweitzer, 33600 Pessac, France
| | - Thibaut Divoux
- Centre de Recherche Paul Pascal, CNRS UPR 8641 - 115 avenue Dr. Schweitzer, 33600 Pessac, France
- MultiScale Material Science for Energy and Environment, UMI 3466, CNRS-MIT, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
| | - Patrick Snabre
- Centre de Recherche Paul Pascal, CNRS UPR 8641 - 115 avenue Dr. Schweitzer, 33600 Pessac, France
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16
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Canevali C, Fasoli M, Bertasa M, Botteon A, Colombo A, Di Tullio V, Capitani D, Proietti N, Scalarone D, Sansonetti A. A multi-analytical approach for the study of copper stain removal by agar gels. Microchem J 2016. [DOI: 10.1016/j.microc.2016.07.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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17
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Ferromagnetic particles as magnetic resonance imaging temperature sensors. Nat Commun 2016; 7:12415. [PMID: 27503610 PMCID: PMC4980494 DOI: 10.1038/ncomms12415] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 06/30/2016] [Indexed: 02/01/2023] Open
Abstract
Magnetic resonance imaging is an important technique for identifying different types of tissues in a body or spatial information about composite materials. Because temperature is a fundamental parameter reflecting the biological status of the body and individual tissues, it would be helpful to have temperature maps superimposed on spatial maps. Here we show that small ferromagnetic particles with a strong temperature-dependent magnetization, can be used to produce temperature-dependent images in magnetic resonance imaging with an accuracy of about 1 °C. This technique, when further developed, could be used to identify inflammation or tumours, or to obtain spatial maps of temperature in various medical interventional procedures such as hyperthermia and thermal ablation. This method could also be used to determine temperature profiles inside nonmetallic composite materials. Magnetic resonance imaging can distinguish between different tissue types by measuring the proton distribution in a living sample. Here, the authors demonstrate how this technique can be extended to provide temperature information by using ferromagnetic particles with temperature-dependent magnetization.
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18
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Gossuin Y, Orlando T, Basini M, Henrard D, Lascialfari A, Mattea C, Stapf S, Vuong QL. NMR relaxation induced by iron oxide particles: testing theoretical models. NANOTECHNOLOGY 2016; 27:155706. [PMID: 26933908 DOI: 10.1088/0957-4484/27/15/155706] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Superparamagnetic iron oxide particles find their main application as contrast agents for cellular and molecular magnetic resonance imaging. The contrast they bring is due to the shortening of the transverse relaxation time T 2 of water protons. In order to understand their influence on proton relaxation, different theoretical relaxation models have been developed, each of them presenting a certain validity domain, which depends on the particle characteristics and proton dynamics. The validation of these models is crucial since they allow for predicting the ideal particle characteristics for obtaining the best contrast but also because the fitting of T 1 experimental data by the theory constitutes an interesting tool for the characterization of the nanoparticles. In this work, T 2 of suspensions of iron oxide particles in different solvents and at different temperatures, corresponding to different proton diffusion properties, were measured and were compared to the three main theoretical models (the motional averaging regime, the static dephasing regime, and the partial refocusing model) with good qualitative agreement. However, a real quantitative agreement was not observed, probably because of the complexity of these nanoparticulate systems. The Roch theory, developed in the motional averaging regime (MAR), was also successfully used to fit T 1 nuclear magnetic relaxation dispersion (NMRD) profiles, even outside the MAR validity range, and provided a good estimate of the particle size. On the other hand, the simultaneous fitting of T 1 and T 2 NMRD profiles by the theory was impossible, and this occurrence constitutes a clear limitation of the Roch model. Finally, the theory was shown to satisfactorily fit the deuterium T 1 NMRD profile of superparamagnetic particle suspensions in heavy water.
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Affiliation(s)
- Y Gossuin
- Biomedical Physics Department, University of Mons, 24, Avenue du Champ de Mars, B-7000, Mons, Belgium
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19
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Delangre S, Vuong QL, Po C, Gallez B, Gossuin Y. Improvement of the Off-Resonance Saturation, an MRI sequence for positive contrast with SPM particles: Theoretical and experimental study. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 265:99-107. [PMID: 26894477 DOI: 10.1016/j.jmr.2016.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Revised: 02/02/2016] [Accepted: 02/04/2016] [Indexed: 06/05/2023]
Abstract
The SuperParaMagnetic particles (SPM particles) are used as contrast agents in MRI and produce negative contrast with conventional T2 or T2(∗)-weighted sequences. Unfortunately, the SPM particle detection on images acquired with such sequences is sometimes difficult because negative contrast can be created by artifacts such as air bubbles or calcification. To overcome this problem, new sequences as Off-Resonance Saturation (ORS) were developed to produce positive contrast with SPM particles. This work explores a new way to optimize the contrast generated by the ORS sequence by increasing the number of saturation pulses applied before the imaging sequence. This modified sequence is studied with numerical simulations and experiments on agarose gel phantoms. A theoretical model able to predict the contrast for different values of the sequence parameters is also developed. The results show that the contrast increases with the saturation pulses number with an optimal value of three saturation pulses in order to avoid artifacts and limit the Specific Absorption Rate (SAR) effect. The dependence of the contrast on the SPM particle concentration and sequence parameters is comparable to what was observed for the ORS sequence.
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Affiliation(s)
- S Delangre
- Biomedical Physics Unit, Université de Mons, Place du Parc 20, 7000 Mons, Belgium
| | - Q L Vuong
- Biomedical Physics Unit, Université de Mons, Place du Parc 20, 7000 Mons, Belgium
| | - C Po
- Biomedical Magnetic Resonance Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - B Gallez
- Biomedical Magnetic Resonance Research Group, Louvain Drug Research Institute, Université Catholique de Louvain, Brussels, Belgium
| | - Y Gossuin
- Biomedical Physics Unit, Université de Mons, Place du Parc 20, 7000 Mons, Belgium.
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20
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Garaga MN, Persson M, Yaghini N, Martinelli A. Local coordination and dynamics of a protic ammonium based ionic liquid immobilized in nano-porous silica micro-particles probed by Raman and NMR spectroscopy. SOFT MATTER 2016; 12:2583-2592. [PMID: 26838120 DOI: 10.1039/c5sm02736e] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Room temperature ionic liquids confined in a solid material, for example, nano-porous silica, are particularly propitious for energy related applications. The aim of this study is to probe the molecular interactions established between the protic ionic liquid diethylmethylammonium methanesulfonate (DEMA-OMs) and silica, where the latter consists of nano-porous micro-particles with pores in the size range of 10 nm. The changes in the local coordination and transport properties induced by the nano-confinement of the ionic liquid are investigated by a combination of Raman and solid-state NMR spectroscopy. In particular, one-dimensional (1D) (1)H and (29)Si and two-dimensional (2D) (29)Si{(1)H} HETOCR solid-state NMR are combined to identify the sites of interaction at the silica-ionic liquid interface. Pulsed field gradient (PFG) NMR experiments are performed to estimate the self-diffusion of both bulk and nano-confined DEMA-OMs. Complementary information on the overall coordination and interaction scheme is achieved by Raman spectroscopy. All these advanced experimental techniques are revealed to be crucial to differentiate between ionic liquid molecules residing in the inter- or intra-particle domains.
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Affiliation(s)
- Mounesha N Garaga
- Department of Chemistry and Chemical Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden.
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21
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Diffusion of water from a range of conservation treatment gels into paint films studied by unilateral NMR. Microchem J 2016. [DOI: 10.1016/j.microc.2015.09.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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22
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Ebert S, Bannwarth MB, Musyanovych A, Landfester K, Münnemann K. How morphology influences relaxivity - comparative study of superparamagnetic iron oxide-polymer hybrid nanostructures. CONTRAST MEDIA & MOLECULAR IMAGING 2015; 10:456-64. [PMID: 26153149 DOI: 10.1002/cmmi.1648] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 04/30/2015] [Accepted: 05/06/2015] [Indexed: 12/12/2022]
Abstract
Superparamagnetic iron oxides (SPIOs) are widely used in MRI as T2 contrast agents, and interest is still growing. Here, the T2 relaxivity of three different SPIO-polymer hybrid morphologies, i.e. homogeneously distributed iron oxide within a polymer matrix, Janus-like nanoparticles and polymer nanocapsules containing iron oxides, is studied. Making use of calculations based on theory for agglomerated systems, the obtained T2 values could be predicted for all different morphologies, except for nanocapsules. Nanocapsules, in contrast to full spheres, allow for water exchange between encapsulated water and bulk water, and thus have two contributions to relaxivity. One originates from the capsules acting as a weakly magnetized cluster and the other stems from the individual SPIOs inside the capsule. Therefore, the relaxivities were also computed using an empirical equation found in the literature, which considers water exchange, resulting in a better T2 forecast for the nanocapsules. The presented study is the first example of a comparison between measured and calculated relaxivities of nanocapsules.
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Affiliation(s)
- Sandro Ebert
- Max Planck Institute for Polymer Research, Mainz, Germany
| | - Markus B Bannwarth
- Max Planck Institute for Polymer Research, Mainz, Germany.,Graduate School Materials Science in Mainz, Mainz, Germany
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23
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Tunnicliffe EM, Scott AD, Ferreira P, Ariga R, McGill LA, Nielles-Vallespin S, Neubauer S, Pennell DJ, Robson MD, Firmin DN. Intercentre reproducibility of cardiac apparent diffusion coefficient and fractional anisotropy in healthy volunteers. J Cardiovasc Magn Reson 2014; 16:31. [PMID: 24886285 PMCID: PMC4028111 DOI: 10.1186/1532-429x-16-31] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 04/17/2014] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Diffusion tensor cardiac magnetic resonance (DT-CMR) enables probing of the microarchitecture of the myocardium, but the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) reported in healthy volunteers have been inconsistent. The aim of this study was to validate a stimulated-echo diffusion sequence using phantoms, and to assess the intercentre reproducibility of in-vivo diffusion measures using the sequence. METHODS AND RESULTS A stimulated-echo, cardiac-gated DT-CMR sequence with a reduced-field-of-view, single-shot EPI readout was used at two centres with 3 T MRI scanners. Four alkane phantoms with known diffusivities were scanned at a single centre using a stimulated echo sequence and a spin-echo Stejskal-Tanner diffusion sequence. The median (maximum, minimum) difference between the DT-CMR sequence and Stejskal-Tanner sequence was 0.01 (0.04, 0.0006) × 10(-3) mm2/s (2%), and between the DT-CMR sequence and literature diffusivities was 0.02 (0.05, 0.006) × 10(-3) mm2/s (4%).The same ten healthy volunteers were scanned using the DT-CMR sequence at the two centres less than seven days apart. Average ADC and FA were calculated in a single mid-ventricular, short axis slice. Intercentre differences were tested for statistical significance at the p < 0.05 level using paired t-tests. The mean ADC ± standard deviation for all subjects averaged over both centres was 1.10 ± 0.06 × 10(-3) mm2/s in systole and 1.20 ± 0.09 × 10-3 mm2/s in diastole; FA was 0.41 ± 0.04 in systole and 0.54 ± 0.03 in diastole. With similarly-drawn regions-of-interest, systolic ADC (difference 0.05 × 10(-3) mm2/s), systolic FA (difference 0.003) and diastolic FA (difference 0.01) were not statistically significantly different between centres (p > 0.05), and only the diastolic ADC showed a statistically significant, but numerically small, difference of 0.07 × 10(-3) mm2/s (p = 0.047). The intercentre, intrasubject coefficients of variance were: systolic ADC 7%, FA 6%; diastolic ADC 7%, FA 3%. CONCLUSIONS This is the first study to demonstrate the accuracy of a stimulated-echo DT-CMR sequence in phantoms, and demonstrates the feasibility of obtaining reproducible ADC and FA in healthy volunteers at separate centres with well-matched sequences and processing.
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Affiliation(s)
- Elizabeth M Tunnicliffe
- Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Andrew D Scott
- NIHR Cardiovascular BRU, Royal Brompton Hospital & Imperial College, London, UK
| | - Pedro Ferreira
- NIHR Cardiovascular BRU, Royal Brompton Hospital & Imperial College, London, UK
| | - Rina Ariga
- Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Laura-Ann McGill
- NIHR Cardiovascular BRU, Royal Brompton Hospital & Imperial College, London, UK
| | - Sonia Nielles-Vallespin
- NIHR Cardiovascular BRU, Royal Brompton Hospital & Imperial College, London, UK
- National Heart Lung and Blood Institute (NHLBI), National Institutes of Health (NIH), DHHS, Bethesda, MD, USA
| | - Stefan Neubauer
- Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Dudley J Pennell
- NIHR Cardiovascular BRU, Royal Brompton Hospital & Imperial College, London, UK
| | - Matthew D Robson
- Oxford Centre for Clinical Magnetic Resonance Research, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - David N Firmin
- NIHR Cardiovascular BRU, Royal Brompton Hospital & Imperial College, London, UK
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24
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De Maria C, Rincon J, Duarte AA, Vozzi G, Boland T. A new approach to fabricate agarose microstructures. POLYM ADVAN TECHNOL 2013. [DOI: 10.1002/pat.3162] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Carmelo De Maria
- Research Center E. Piaggio; University of Pisa; Italy
- Let People Move Research Institute; Bioengineering Division; Arezzo Italy
| | - Julio Rincon
- Department of Metallurgical and Materials Engineering; University of Texas at El Paso; Texas USA
| | - Alonso A. Duarte
- Department of Metallurgical and Materials Engineering; University of Texas at El Paso; Texas USA
| | | | - Thomas Boland
- Department of Metallurgical and Materials Engineering; University of Texas at El Paso; Texas USA
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25
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Carini E, Curti E, Littardi P, Luzzini M, Vittadini E. Water dynamics of ready to eat shelf stable pasta meals during storage. INNOV FOOD SCI EMERG 2013. [DOI: 10.1016/j.ifset.2012.09.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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26
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Omata S, Sonokawa S, Sawae Y, Murakami T. Effects of both vitamin C and mechanical stimulation on improving the mechanical characteristics of regenerated cartilage. Biochem Biophys Res Commun 2012; 424:724-9. [DOI: 10.1016/j.bbrc.2012.07.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2012] [Accepted: 07/09/2012] [Indexed: 12/22/2022]
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28
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Özcan A, Quirk JD, Wang Y, Wang Q, Sun P, Spees WM, Song SK. The validation of complete Fourier direct MR method for diffusion MRI via biological and numerical phantoms. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:3756-9. [PMID: 22255156 DOI: 10.1109/iembs.2011.6090640] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The equations of the Complete Fourier Direct (CFD) MR model are explicitly derived for diffusion weighted NMR experiments. The CFD-MR theory is validated by comparing a biological phantom constructed from nerve bundles and agar gel with its numerical implementation. The displacement integral distribution function estimated from the experimental data is in high agreement with the numerical phantom. CFD-MR's ability to estimate accurately and fully spin diffusion properties demonstrated here, provides the experimental validation of the theoretical CFD-MR model.
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Affiliation(s)
- Alpay Özcan
- Mallinckrodt Institute of Radiology, Washington University in Saint Louis, School of Medicine, St Louis, MO 63110, USA.
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29
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Huang Y, Davies E, Lillford P. Effect of solutes and matrix structure on water mobility in glycerol-agar-water gel systems: a nuclear magnetic resonance approach. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:4078-4087. [PMID: 21375332 DOI: 10.1021/jf104856x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Nuclear magnetic resonance spectroscopy (NMR) has been widely used to determine water molecular mobility in food systems. This study aimed to examine the effects of matrix structure and solutes on the dynamics of water molecules in model mixed systems, glycerol-agar-water gels, using low- and high-resolution NMR. Simple models to explain water relaxation rates and self-diffusion coefficients in mixed systems were developed using the experimental values obtained for the individual binary systems (glycerol-water solutions and agar-water gels). The spin-lattice relaxation of mixed systems was influenced by interactions of both glycerol and agar with water, while the spin-spin relaxation of mixed systems was dominated by the interaction of agar with water. Water diffusion was influenced by not only molecular interactions between all components but also the gel matrix structure. These models are able to differentiate the effect of solutes from that of matrix structure on water molecular dynamics.
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Affiliation(s)
- Yang Huang
- CSIRO Food and Nutritional Sciences, North Ryde, NSW 2113, Australia.
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