| 1. |
- Jo, Y. S., et al.
(författare)
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Encapsulation of bovine serum albumin in temperature-programmed shell-in-shell structures
- 2003
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Ingår i: Macromolecular rapid communications. - : Wiley. - 1022-1336 .- 1521-3927. ; 24:16, s. 957-962
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Tidskriftsartikel (refereegranskat)abstract
- A novel approach to load a hydrophilic bovine serum albumin into drug carriers was proposed in terms of temperature-programmed shell-in-shell structures, which were fabricated with poly(N-isopropylacrlamide), poly(lactide), poly(ethylene glycol), and Au nanoparticles. Spherically well-defined shell-in-shell structures were constructed by a modified-double-emulsion method (MDEM). The lower critical solubility temperature of the structures was manipulated to 36.4degreesC which was confirmed by UV/Vis spectroscopy and DSC (Differential Scanning Calorimetry).
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| 2. |
- Alcorn, J, et al.
(författare)
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Basic instrumentation for Hall A at Jefferson Lab
- 2004
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 522:3, s. 294-346
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Tidskriftsartikel (refereegranskat)abstract
- The instrumentation in Hall A at the Thomas Jefferson National Accelerator Facility was designed to study electro-and photo-induced reactions at very high luminosity and good momentum and angular resolution for at least one of the reaction products. The central components of Hall A are two identical high resolution spectrometers, which allow the vertical drift chambers in the focal plane to provide a momentum resolution of better than 2 x 10(-4). A variety of Cherenkov counters, scintillators and lead-glass calorimeters provide excellent particle identification. The facility has been operated successfully at a luminosity well in excess of 10(38) CM-2 s(-1). The research program is aimed at a variety of subjects, including nucleon structure functions, nucleon form factors and properties of the nuclear medium. (C) 2003 Elsevier B.V. All rights reserved.
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| 3. |
- Bigelow, NH, et al.
(författare)
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Climate change and Arctic ecosystems: 1. Vegetation changes north of 55 degrees N between the last glacial maximum, mid-Holocene, and present
- 2003
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Ingår i: Journal of Geophysical Research. - 2156-2202. ; 108:D19
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Forskningsöversikt (refereegranskat)abstract
- [1] A unified scheme to assign pollen samples to vegetation types was used to reconstruct vegetation patterns north of 55degreesN at the last glacial maximum (LGM) and mid-Holocene (6000 years B. P.). The pollen data set assembled for this purpose represents a comprehensive compilation based on the work of many projects and research groups. Five tundra types (cushion forb tundra, graminoid and forb tundra, prostrate dwarf-shrub tundra, erect dwarf-shrub tundra, and low- and high-shrub tundra) were distinguished and mapped on the basis of modern pollen surface samples. The tundra-forest boundary and the distributions of boreal and temperate forest types today were realistically reconstructed. During the mid-Holocene the tundra-forest boundary was north of its present position in some regions, but the pattern of this shift was strongly asymmetrical around the pole, with the largest northward shift in central Siberia (similar to200 km), little change in Beringia, and a southward shift in Keewatin and Labrador (similar to200 km). Low- and high-shrub tundra extended farther north than today. At the LGM, forests were absent from high latitudes. Graminoid and forb tundra abutted on temperate steppe in northwestern Eurasia while prostrate dwarf-shrub, erect dwarf-shrub, and graminoid and forb tundra formed a mosaic in Beringia. Graminoid and forb tundra is restricted today and does not form a large continuous biome, but the pollen data show that it was far more extensive at the LGM, while low- and high-shrub tundra were greatly reduced, illustrating the potential for climate change to dramatically alter the relative areas occupied by different vegetation types.
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| 4. |
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| 5. |
- Jo, Yunsuk, et al.
(författare)
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A novel thermosensitive composite fabricated with au nanoparticles, poly(lactide), and poly(N-isopropylacrylamide)
- 2004
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Ingår i: Functional Nanomaterials For Optoelectronics And Other Applications. ; , s. 161-164
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Konferensbidrag (refereegranskat)abstract
- A novel approach to load a hydrophilic bovine serum albumin (BSA) into the drug carriers was proposed in terms of thermosensitive dual-shell structures which were fabricated with poly(N-isopropylacrylamide), poly(lactide) and Au nanoparticles. Spherically well-defined dual-shell structures were constructed by a modified-double-emulsion method (MDEM). The lower critical solubility temperature of the structures was shifted to 36.4 degreesC which was confirmed by UV-Vis spectroscopy.
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| 6. |
- Jo, Yunsuk, et al.
(författare)
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Mathematical modelling on the controlled-release of indomethacin-encapsulated poly(lactic acid-co-ethylene oxide) nanospheres
- 2004
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 15:9, s. 1186-1194
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Tidskriftsartikel (refereegranskat)abstract
- The in vitro release behaviour of indomethacin (IMC, 1-[p-chlorobenzoyl]-2-methyl-5-methoxy-3-indoleacetic acid) encapsulated in poly(lactic acid-co-ethylene oxide) (PLA-PEO) nanospheres is investigated based on two mathematical models: the diffusion model derived from Fick's law and the dissolution model from the mass balance of IMC. A dual chamber transport system (DCTS) is designed and used for the in vitro experiment. The release behaviour of IMC from the PLA-PEO drug delivery systems (DDSs) is compared to the mathematical models suggested in this work. The synthesis of PLA-PEO and the fabrication of the IMC-loaded PLA-PEO DDSs are discussed and characterized by H-1 NMR, transmission electron microscopy (TEM) and quasi-elastic light scattering (QELS) spectroscopy. Spherical PLA-PEO nanospheres are well prepared as a model DDS as suggested by the characterization results. The overall releasing behaviour of the model drug can be manipulated by varying several key parameters including the volumetric ratio between the organic and the aqueous phase (V-r), the partition coefficient (K-p) and the encapsulation efficiency (EE). Modelling results show that the releasing mechanism is different depending on the particle size. When large PLA-PEO nanospheres are fabricated, the dissolution mechanism can be effective, as the dissolution of IMC can be a rate-determining step due to its high hydrophobicity in an aqueous surrounding medium. In this manner, the optimum DDS can be suitably designed and the releasing profile can be also estimated by considering several major factors for a specific type of substance and its purpose.
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| 7. |
- Jo, Y. S., et al.
(författare)
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Synchronous delivery systems composed of Au nanoparticles and stimuli-sensitive diblock terpolymer
- 2004
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Ingår i: Journal of materials science. Materials in medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 15:12, s. 1291-1295
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Tidskriftsartikel (refereegranskat)abstract
- A method to construct synchronous delivery systems via direct self-assembly of Au nanoparticles on the poly[(N-isopropylacrylamide-r-acrylamide)-b-L-lactic acid] (PNAL) nanospheres has been presented in this paper. To achieve amphiphilic diblock terpolymer, hydrophobic poly (L-lactic acid) (PLLA) block was added to poly(N-isopropylacrylamide-r-ac rylamide) (PNA) block via Michel-type addition reaction. Lower critical solubility temperature (LCST) was modulated at 35.6 degreesC which is close to the body temperature, but higher than poly(N-isopropylacrylamide) (PNIPAAm) homopolymer by controlling the ratio between isopropylacrylamide (IPAAm) monomers and acrylamide (AAm) monomers. Using this amphiphilic diblock terpolymer, PNAL nanospheres were fabricated by emulsion/evaporation technique followed by direct self-assembly of Au nanoparticles on the PNAL nanospheres due to the high affinity of amino groups donated from PNA block. The 'core' site of Au@)PNAL nanospheres can load various lyphophilic drugs. Moreover, Au nanoparticles in the 'shell' domain of PNAL nanospheres give optimal environment to conjugate various biomolecules. Therefore, it is expected that Au@PNAL hybrid nanospheres can be utilized in synchronous delivery of both biomolecules in the 'shell' domain and various therapeutic drugs in the 'core' domain.
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