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Gel Particles (gel + particle)

Distribution by Scientific Domains

Polymers and Materials Science	85%

Selected Abstracts

Dual Tuning of the Photonic Band-Gap Structure in Soft Photonic Crystals

ADVANCED MATERIALS, Issue 18 2009
Masaki Honda
A dually tunable photonic crystal composed of thermosensitive gel particles confined in a pH-sensitive inverse-opal gel is reported. The position of the photonic band-gap can be thermally regulated, while its intensity is dramatically changed by pH. Reversible, independent, and extensive switching of the position and intensity of the photonic band-gap could be achieved using independent external stimuli. [source]

Preparation and optical properties of an all-polymer light modulator using colored N -isopropylacrylamide gel particles in a gel-in-gel system

JOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2007
Hiroaki Tsutsui
Abstract A novel all-polymer light modulator with a gel-in-gel system was developed. The gel-in-gel system was constructed with colored gel particles responsive to stimuli held independently in another stimuli-nonresponsive gel matrix. Well-known thermoresponsive N -isopropylacrylamide (NIPAM) gel particles containing a pigment were dispersed and fixed in an outer stimuli-nonresponsive gel matrix. When poly(vinyl alcohol),styrylpyridinium (PVA,SbQ) was used for the outer gel matrix, the light modulator showed excellent color-changing properties because the PVA,SbQ matrix was selectively formed around the NIPAM gel particles and the particles exhibited a large volume change in the matrix. The temperature when the outer gel matrix was formed affected the haze of the light modulator. When the outer gel matrix was formed in the swollen state of the NIPAM gels, the haze of a light modulator increased with heating. On the contrary, the haze of a light modulator prepared in the shrunken state of the NIPAM gels decreased with heating. The response time of the color change was less than 1 s. The gel-in-gel system made a very fast macroscopic color change, taking advantage of the fast response of the micrometer-sized gel particles. We believe that a light modulator with a gel-in-gel system may find various applications in optical devices. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 2295,2303, 2007 [source]

Recycling of tire-curing bladder by ultrasonic devulcanization

POLYMER ENGINEERING & SCIENCE, Issue 1 2006
Wenlai Feng
The recycling of butyl rubber-based tire-curing bladder was carried out by means of a grooved barrel ultrasonic extruder. Die pressure and ultrasonic power consumption were measured as a function of flow rate and ultrasonic amplitude. Gel fraction and crosslink density of the ultrasonically devulcanized rubber were substantially reduced. In turn, this led to some reduction in gel fraction and crosslink density in the revulcanized rubber. These findings were correlated with dynamic properties and the cure behavior of the devulcanized rubber. The mechanical properties of the revulcanized rubber, dependent on processing conditions during devulcanization, were compared with that of the virgin vulcanizate. Good mechanical properties of revulcanized rubber was achieved with 86 and 71% retention of the tensile strength and the elongation at break respectively, and with modulus increased by 44%. The devulcanized rubber was found to contain tiny gel particles of a wide size distribution with a predominant size of <4 ,m. POLYM. ENG. SCI., 46:8,18, 2006. © 2005 Society of Plastics Engineers [source]

Fluorescent gel particles in the nanometer range for detection of metabolites in living cells,

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 9-10 2006
Kristoffer Almdal
Abstract In this present work a research program that aims at the development of sensor particles based on ratiometric detection of fluorescence from two dyes was embarked on. Such particles can in principle be used to achieve spatially and time resolved measurements of metabolite concentrations in living cells. The dyes are chosen such that the fluorescence of one dye is a function of an analyte concentration whereas the fluorescence of the other dye is independent of variations in the medium. Methods have been investigated for synthesizing such particles based on crosslinked polyacrylamide in inverse micelles in oil microemulsions. Typical sizes of the particles are tens of nanometers. Characterization methods for such particles based on size exclusion chromatography, photon correlation spectroscopy, scanning electron microscopy, and atomic force microscopy have been developed. The stability of the sensor particles and their potential as an analytical tool will be discussed. Copyright © 2006 John Wiley & Sons, Ltd. [source]

Angiographic subsegmentectomy for the treatment of patients with small hepatocellular carcinoma

CANCER, Issue 4 2003
Shozo Iwamoto M.D.
Abstract BACKGROUND The therapeutic results of nonsurgical treatment for patients with hepatocellular carcinoma (HCC) have been poor, and improved treatments are needed. The authors recently developed a new technique called angiographic subsegmentectomy for the treatment of patients with small HCC. METHODS The technique includes confirming the diagnosis of small HCC using a helical computed tomography (CT) scan combined with an angiography system for identifying the tumor-feeding subsegmental hepatic artery, injecting lipiodol containing farmorubicin until it enters the portal vein in sufficient amounts, and injecting sponge particles into the hepatic artery for embolization. Occlusion of the hepatic artery with gel particles and occlusion of the portal vein by lipiodol induce infarction necrosis, which encompasses the entire tumor and the surrounding liver parenchyma. RESULTS The treatment was given to 23 patients with 30 HCC tumors that measured < 20 mm in greatest dimension. It was successful in all 23 patients. Serum alanine aminotransferase levels were elevated to a significant level in the majority of patients after treatment, mild ascites developed in three patients, and the patients complained of pain and fever posttreatment that were controlled readily. No patients developed hepatic failure. Only one patient developed recurrent disease posttreatment at 1.5 years, for a recurrence rate of 5% at 1 year and 6.6% at 1.5 years, a rate that has never been achieved with other treatment modalities. CONCLUSIONS Angiographic subsegmentectomy is a novel treatment for patients with small HCC. The results indicated that it is equivalent to undergoing small resection and is superior to conventional arterial chemoembolization. Cancer 2003;97:1051,6. © 2003 American Cancer Society. DOI 10.1002/cncr.11106 [source]