101
|
Xie D, Lista M, Qiao GG, Dunstan DE. Shear Induced Alignment of Low Aspect Ratio Gold Nanorods in Newtonian Fluids. J Phys Chem Lett 2015; 6:3815-20. [PMID: 26722876 DOI: 10.1021/acs.jpclett.5b01641] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The flow-induced alignment of small gold nanorods ranging in aspect ratio from 2.4 to 4.2 in aqueous sucrose solutions is reported. Optical absorption spectra have been measured over a range of shear rates using polarized incident light in an optically transparent quartz Couette cell. The measured spectral changes are directly attributed to the shear-induced anisotropy in the suspension due to particle alignment that saturates at Péclet number of around 200. The measured optical changes are reversible, indicating that the nanorods do not undergo aggregation during measurement. Numerical simulations show that the spectral shifts are consistent with the rods flipping between extreme orientations of the Jeffery's orbits and that the effect of the Brownian motion on the gold nanorods cannot be ignored even at large Péclet number.
Collapse
|
102
|
McKenzie TG, Wong EHH, Fu Q, Sulistio A, Dunstan DE, Qiao GG. Controlled Formation of Star Polymer Nanoparticles via Visible Light Photopolymerization. ACS Macro Lett 2015; 4:1012-1016. [PMID: 35596438 DOI: 10.1021/acsmacrolett.5b00530] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
A recently developed visible light mediated photocontrolled radical polymerization technique using trithiocarbonates (i.e., conventional RAFT agents) as the sole control agent in the absence of additional photoinitiators or catalysts is utilized for the synthesis of core cross-linked star (CCS) polymer nanoparticles. The attractive features of this photopolymerization system, including high end-group fidelity at (near) complete monomer conversion, are exploited to facilitate a high-yielding, one-pot pathway toward well-defined star polymer products. Moreover, reinitiation of the photoactive trithiocarbonate moieties from within the star core is demonstrated to form (pseudo)miktoarm stars via an "in-out" approach, showing extremely high initiation efficiency (95%).
Collapse
|
103
|
Cai XJ, Yuan HM, Blencowe A, Qiao GG, Genzer J, Spontak RJ. Film-Stabilizing Attributes of Polymeric Core-Shell Nanoparticles. ACS NANO 2015; 9:7940-7949. [PMID: 26146164 DOI: 10.1021/acsnano.5b00237] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Self-organization of nanoparticles into stable, molecularly thin films provides an insightful paradigm for manipulating the manner in which materials interact at nanoscale dimensions to generate unique material assemblies at macroscopic length scales. While prior studies in this vein have focused largely on examining the performance of inorganic or organic/inorganic hybrid nanoparticles (NPs), the present work examines the stabilizing attributes of fully organic core-shell microgel (CSMG) NPs composed of a cross-linked poly(ethylene glycol dimethacrylate) (PEGDMA) core and a shell of densely grafted, but relatively short-chain, polystyrene (PS) arms. Although PS homopolymer thin films measuring from a few to many nanometers in thickness, depending on the molecular weight, typically dewet rapidly from silica supports at elevated temperatures, spin-coated CSMG NP films measuring as thin as 10 nm remain stable under identical conditions for at least 72 h. Through the use of self-assembled monolayers (SAMs) to alter the surface of a flat silica-based support, we demonstrate that such stabilization is not attributable to hydrogen bonding between the acrylic core and silica. We also document that thin NP films consisting of three or less layers (10 nm) and deposited onto SAMs can be fully dissolved even after extensive thermal treatment, whereas slightly thicker films (40 nm) on Si wafer become only partially soluble during solvent rinsing with and without sonication. Taken together, these observations indicate that the present CSMG NP films are stabilized primarily by multidirectional penetration of relatively short, unentangled NP arms caused by NP layering, rather than by chain entanglement as in linear homopolymer thin films. This nanoscale "velcro"-like mechanism permits such NP films, unlike their homopolymer counterparts of comparable chain length and thickness, to remain intact as stable, free-floating sheets on water, and thus provides a viable alternative to ultrathin organic coating strategies.
Collapse
|
104
|
McKenzie TG, Ren JM, Dunstan DE, Wong EHH, Qiao GG. Synthesis of high-order multiblock core cross-linked star polymers. ACTA ACUST UNITED AC 2015. [DOI: 10.1002/pola.27775] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
105
|
Shirbin SJ, Ladewig K, Fu Q, Klimak M, Zhang X, Duan W, Qiao GG. Cisplatin-Induced Formation of Biocompatible and Biodegradable Polypeptide-Based Vesicles for Targeted Anticancer Drug Delivery. Biomacromolecules 2015; 16:2463-74. [PMID: 26166192 DOI: 10.1021/acs.biomac.5b00692] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Novel cisplatin (CDDP)-loaded, polypeptide-based vesicles for the targeted delivery of cisplatin to cancer cells have been prepared. These vesicles were formed from biocompatible and biodegradable maleimide-poly(ethylene oxide)114-b-poly(L-glutamic acid)12 (Mal-PEG114-b-PLG12) block copolymers upon conjugation with the drug itself. CDDP conjugation forms a short, rigid, cross-linked, drug-loaded, hydrophobic block in the copolymer, and subsequently induces self-assembly into hollow vesicle structures with average hydrodynamic diameters (Dh) of ∼ 270 nm. CDDP conjugation is critical to the formation of the vesicles. The reactive maleimide-PEG moieties that form the corona and inner layer of the vesicles were protected via formation of a reversible Diels-Alder (DA) adduct throughout the block copolymer synthesis so as to maintain their integrity. Drug release studies demonstrated a low and sustained drug release profile in systemic conditions (pH = 7.4, [Cl(-)] = 140 mM) with a higher "burst-like" release rate being observed under late endosomal/lysosomal conditions (pH = 5.2, [Cl(-)] = 35 mM). Further, the peripheral maleimide functionalities on the vesicle corona were conjugated to thiol-functionalized folic acid (FA) (via in situ reduction of a novel bis-FA disulfide, FA-SS-FA) to form an active targeting drug delivery system. These targeting vesicles exhibited significantly higher cellular binding/uptake into and dose-dependent cytotoxicity toward cancer cells (HeLa) compared to noncancerous cells (NIH-3T3), which show high and low folic acid receptor (FR) expression, respectively. This work thus demonstrates a novel approach to polypeptide-based vesicle assembly and a promising strategy for targeted, effective CDDP anticancer drug delivery.
Collapse
|
106
|
McKenzie TG, Fu Q, Wong EHH, Dunstan DE, Qiao GG. Visible Light Mediated Controlled Radical Polymerization in the Absence of Exogenous Radical Sources or Catalysts. Macromolecules 2015. [DOI: 10.1021/acs.macromol.5b00965] [Citation(s) in RCA: 219] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
107
|
Sun H, Wong EHH, Yan Y, Cui J, Dai Q, Guo J, Qiao GG, Caruso F. The role of capsule stiffness on cellular processing. Chem Sci 2015; 6:3505-3514. [PMID: 28706710 PMCID: PMC5492901 DOI: 10.1039/c5sc00416k] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 04/08/2015] [Indexed: 12/18/2022] Open
Abstract
Particle stiffness is emerging as an important parameter in determining the cell uptake dynamics of particles. Understanding the effects of capsule stiffness on their biological behavior is essential for the development of polymer capsules as therapeutic carriers. Herein, we report the preparation of polysaccharide capsules via atom transfer radical polymerization-mediated continuous assembly of polymers (CAPATRP) on silica templates using methacrylated hyaluronic acid (HA) as the macrocrosslinker. This approach affords HA capsules with controllable wall thickness and tunable stiffness. The influence of capsule stiffness on cellular interaction and intracellular distribution is systematically investigated using flow cytometry, imaging flow cytometry, and deconvolution microscopy. The softest HA capsules with a stiffness (γ) of 7.5 mN m-1 possess higher cell surface binding and cellular association when compared to stiffer capsules with γ of 17.6-28.9 mN m-1. Furthermore, the uptake of HA capsules is a stiffness-dependent process, with slower and less cellular internalization observed with increasing capsule stiffness. Nevertheless, regardless of the stiffness, all internalized capsules are deformed and located in the lysosomes. These findings offer insights into the influence of capsule stiffness on cellular interaction as well as intracellular fate, providing information for the design of rational polymer capsules for biomedical applications.
Collapse
|
108
|
Scofield JMP, Gurr PA, Kim J, Fu Q, Halim A, Kentish SE, Qiao GG. High-performance thin film composite membranes with well-defined poly(dimethylsiloxane)-b
-poly(ethylene glycol) copolymer additives for CO2
separation. ACTA ACUST UNITED AC 2015. [DOI: 10.1002/pola.27628] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
109
|
Wong EHH, Qiao GG. Factors Influencing the Formation of Single-Chain Polymeric Nanoparticles Prepared via Ring-Opening Polymerization. Macromolecules 2015. [DOI: 10.1021/ma502526c] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
|
110
|
Zhang J, Jin J, Cooney R, Fu Q, Qiao GG, Thomas S, Merkel TC. Synthesis of perfectly alternating copolymers for polymers of intrinsic microporosity. Polym Chem 2015. [DOI: 10.1039/c5py00570a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A two-pot synthetic strategy was developed to accomplish sequence control in a completely alternating fashion for co-polymers of intrinsic microporosity.
Collapse
|
111
|
Ow SY, Bekard I, Blencowe A, Qiao GG, Dunstan DE. A generic class of amyloid fibril inhibitors. J Mater Chem B 2015; 3:1350-1359. [DOI: 10.1039/c4tb01762e] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Amyloid fibrils are large ordered fibrillar aggregates formed from mis-folded proteins. Fibril formation is inhibited using a generic macromolecular structure.
Collapse
|
112
|
Fu Q, McKenzie TG, Tan S, Nam E, Qiao GG. Tertiary amine catalyzed photo-induced controlled radical polymerization of methacrylates. Polym Chem 2015. [DOI: 10.1039/c5py00840a] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A novel tertiary amine catalyst and trithiocarbonate synergistic photo-induced controlled radical polymerization of methacrylates has been realized under mild UV irradiation, yielding polymethacrylates with low molecular weight distributions and excellent end-group fidelity.
Collapse
|
113
|
Tan S, Nam E, Cui J, Xu C, Fu Q, Ren JM, Wong EHH, Ladewig K, Caruso F, Blencowe A, Qiao GG. Fabrication of ultra-thin polyrotaxane-based films via solid-state continuous assembly of polymers. Chem Commun (Camb) 2015; 51:2025-8. [DOI: 10.1039/c4cc08759c] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Surface-confined ultra-thin polyrotaxane (PRX)-based films with tunable composition, surface topology and swelling characteristics were prepared by solid-state continuous assembly of polymers (ssCAP).
Collapse
|
114
|
Ozmen MM, Fu Q, Kim J, Qiao GG. A rapid and facile preparation of novel macroporous silicone-based cryogels via photo-induced thiol–ene click chemistry. Chem Commun (Camb) 2015; 51:17479-82. [DOI: 10.1039/c5cc07417g] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We prepared novel cryogels via facile thiol–ene reaction at low temperatures, which can selectively remove oils with excellent recyclability.
Collapse
|
115
|
McKenzie TG, Wong EHH, Fu Q, Lam SJ, Dunstan DE, Qiao GG. Highly Efficient and Versatile Formation of Biocompatible Star Polymers in Pure Water and Their Stimuli-Responsive Self-Assembly. Macromolecules 2014. [DOI: 10.1021/ma502008j] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
|
116
|
Ren JM, Qiao GG. Synthetic Strategies towards Well-Defined Complex Polymeric Architectures through Covalent Chemistry. CHEM-ING-TECH 2014. [DOI: 10.1002/cite.201400088] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
|
117
|
Kashani A, San Nicolas R, Qiao GG, van Deventer JS, Provis JL. Modelling the yield stress of ternary cement–slag–fly ash pastes based on particle size distribution. POWDER TECHNOL 2014. [DOI: 10.1016/j.powtec.2014.06.041] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
118
|
Xu C, Peng S, Qiao GG, Gutowski V, Lohse D, Zhang X. Nanobubble formation on a warmer substrate. SOFT MATTER 2014; 10:7857-7864. [PMID: 25156822 DOI: 10.1039/c4sm01025f] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The solvent exchange procedure is an often-used protocol to produce surface nanobubbles. In this procedure, the substrate is exposed to a good solvent for gas which is then mixed and rinsed with a poor solvent for gas and the nanobubbles form on the solid-liquid interface. Here we study the effects of temperatures of the substrate and the first solvent on nanobubble formation. Atomic force microscopy with temperature control was used to examine the formation of nanobubbles at temperatures between 37 °C and 54 °C. It was found that the probability of nanobubble formation was larger on substrates at higher temperatures. Moreover, on warmer substrates we found nanobubbles with lateral extensions up to 8 μm. A morphologic analysis shows that all nanobubbles, including giant nanobubbles, have a similar aspect ratio, independent of the substrate temperature, and that this aspect ratio corresponds to a contact angle between 13° and 22° (on the gas side), much smaller than the macroscopic counterparts. We finally discuss the implications of our results for various theories on nanobubble stability.
Collapse
|
119
|
Gurr PA, Scofield JMP, Kim J, Fu Q, Kentish SE, Qiao GG. Polyimide polydimethylsiloxane triblock copolymers for thin film composite gas separation membranes. ACTA ACUST UNITED AC 2014. [DOI: 10.1002/pola.27401] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
120
|
Christofferson AJ, Yiapanis G, Leung AHM, Prime EL, Tran DNH, Qiao GG, Solomon DH, Yarovsky I. Dynamic performance of duolayers at the air/water interface. 2. Mechanistic insights from all-atom simulations. J Phys Chem B 2014; 118:10927-33. [PMID: 25153318 DOI: 10.1021/jp506098d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The novel duolayer system, comprising a monolayer of ethylene glycol monooctadecyl ether (C18E1) and the water-soluble polymer poly(vinylpyrrolidone) (PVP), has been shown to resist forces such as wind stress to a greater degree than the C18E1 monolayer alone. This paper reports all-atom molecular dynamics simulations comparing the monolayer (C18E1 alone) and duolayer systems under an applied force parallel to the air/water interface. The simulations show that, due to the presence of PVP at the interface, the duolayer film exhibits an increase in chain tilt, ordering, and density, as well as a lower lateral velocity compared to the monolayer. These results provide a molecular rationale for the improved performance of the duolayer system under wind conditions, as well as an atomic-level explanation for the observed efficacy of the duolayer system as an evaporation suppressant, which may serve as a useful guide for future development for thin films where resistance to external perturbation is desirable.
Collapse
|
121
|
Leung AHM, Prime EL, Tran DNH, Fu Q, Christofferson AJ, Yiapanis G, Yarovsky I, Qiao GG, Solomon DH. Dynamic performance of duolayers at the air/water interface. 1. Experimental analysis. J Phys Chem B 2014; 118:10919-26. [PMID: 25155024 DOI: 10.1021/jp5060974] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Understanding, and improving, the behavior of thin surface films under exposure to externally applied forces is important for applications such as mimicking biological membranes, water evaporation mitigation, and recovery of oil spills. This paper demonstrates that the incorporation of a water-soluble polymer into the surface film composition, i.e., formation of a three-duolayer system, shows improved performance under an applied dynamic stress, with an evaporation saving of 84% observed after 16 h, compared to 74% for the insoluble three-monolayer alone. Canal viscometry and spreading rate experiments, performed using the same conditions, demonstrated an increased surface viscosity and faster spreading rate for the three-duolayer system, likely contributing to the observed improvement in dynamic performance. Brewster angle microscopy and dye-tagged polymers were used to visualize the system and demonstrated that the duolayer and monolayer system both form a homogeneous film of uniform, single-molecule thickness, with the excess material compacting into small floating reservoirs on the surface. It was also observed that both components have to be applied to the water surface together in order to achieve improved performance under dynamic conditions. These findings have important implications for the use of surface films in various applications where resistance to external disturbance is required.
Collapse
|
122
|
Ozcelik B, Brown KD, Blencowe A, Ladewig K, Stevens GW, Scheerlinck JPY, Abberton K, Daniell M, Qiao GG. Biodegradable and biocompatible poly(ethylene glycol)-based hydrogel films for the regeneration of corneal endothelium. Adv Healthc Mater 2014; 3:1496-507. [PMID: 24652807 DOI: 10.1002/adhm.201400045] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Indexed: 12/16/2022]
Abstract
Corneal endothelial cells (CECs) are responsible for maintaining the transparency of the human cornea. Loss of CECs results in blindness, requiring corneal transplantation. In this study, fabrication of biocompatible and biodegradable poly(ethylene glycol) (PEG)-based hydrogel films (PHFs) for the regeneration and transplantation of CECs is described. The 50-μm thin hydrogel films have similar or greater tensile strengths to human corneal tissue. Light transmission studies reveal that the films are >98% optically transparent, while in vitro degradation studies demonstrate their biodegradation characteristics. Cell culture studies demonstrate the regeneration of sheep corneal endothelium on the PHFs. Although sheep CECs do not regenerate in vivo, these cells proliferate on the films with natural morphology and become 100% confluent within 7 d. Implantation of the PHFs into live sheep corneas demonstrates the robustness of the films for surgical purposes. Regular slit lamp examinations and histology of the cornea after 28 d following surgery reveal minimal inflammatory responses and no toxicity, indicating that the films are benign. The results of this study suggest that PHFs are excellent candidates as platforms for the regeneration and transplantation of CECs as a result of their favorable biocompatibility, degradability, mechanical, and optical properties.
Collapse
|
123
|
Tan S, Ladewig K, Fu Q, Blencowe A, Qiao GG. Macromol. Rapid Commun. 13/2014. Macromol Rapid Commun 2014. [DOI: 10.1002/marc.201470042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
124
|
Wong EHH, Lam SJ, Nam E, Qiao GG. Biocompatible Single-Chain Polymeric Nanoparticles via Organo-Catalyzed Ring-Opening Polymerization. ACS Macro Lett 2014; 3:524-528. [PMID: 35590720 DOI: 10.1021/mz500225p] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
This study presents a novel approach to synthesize biocompatible single-chain polymeric nanoparticles (SCPN) under mild reaction conditions via organo-catalyzed ring-opening polymerization (ROP). Linear polymeric precursors containing pendent polymerizable caprolactone groups, made by reversible addition-fragmentation chain transfer (RAFT) polymerization, were intramolecularly cross-linked via ROP in the presence of benzyl alcohol (nucleophilic initiator) and methanesulfonic acid (organo catalyst) to form discrete, well-defined SCPN, as confirmed by GPC, DLS, 1H NMR, and AFM analysis. The formed SCPN are tunable in size (2-5 nm), depending on the molecular weight of the parent linear macromolecule. Furthermore, cytotoxicity studies revealed that the SCPN, which were covalently cross-linked by biodegradable polyester linkages, were nontoxic toward human embryonic kidney (HEK293T) cells. This study demonstrates the efficiency and versatility of this approach to generate uniformly sized soft nanoparticles with tunable dimensions that are potentially useful for a range of targeted applications, including drug delivery systems and membranes for gas separation technologies.
Collapse
|
125
|
Tan S, Ladewig K, Fu Q, Blencowe A, Qiao GG. Cyclodextrin-Based Supramolecular Assemblies and Hydrogels: Recent Advances and Future Perspectives. Macromol Rapid Commun 2014; 35:1166-84. [DOI: 10.1002/marc.201400080] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 03/07/2014] [Indexed: 12/22/2022]
|