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121.
Physicochemical characterization of diclofenac sodium-loaded poloxamer gel as a rectal delivery system with fast absorption 总被引:1,自引:0,他引:1
Yong CS Sah H Jahng Y Chang HW Son JK Lee SH Jeong TC Rhee JD Baek SH Kim CK Choi HG 《Drug development and industrial pharmacy》2003,29(5):545-553
Rectal poloxamer gel systems composed of poloxamers and bioadhesive polymers were easy to administer to the anus and were mucoadhesive to the rectal tissues without leakage after the dose. However, a poloxamer gel containing diclofenac sodium could not be developed using bioadhesive polymers, since the drug was precipitated in this preparation. To develop a poloxamer gel using sodium chloride instead of bioadhesive polymers, the physicochemical properties such as gelation temperature, gel strength, and bioadhesive force of various formulations composed of diclofenac sodium, poloxamers, and sodium chloride were investigated. Furthermore, the pharmacokinetic study of diclofenac sodium delivered by the poloxamer gel was performed. Diclofenac sodium significantly increased the gelation temperature and weakened the gel strength and bioadhesive force, while sodium chloride did the opposite. The poloxamer gels with less than 1.0% sodium chloride, in which the drug was not precipitated, were inserted into the rectum without difficulty and leakage, and were retained in the rectum of rats for at least 6 hr. Furthermore, poloxamer gel gave significantly higher initial plasma concentrations and faster Tmax of diclofenac sodium than did solid suppository, indicating that drug from poloxamer gel could be absorbed faster than that from the solid one in rats. Our results suggested that a rectal poloxamer gel system with sodium chloride and poloxamers was a more physically stable, convenient, and effective rectal dosage form for diclofenac sodium. 相似文献
122.
Kok-Meng Lee Hungsun Son 《IEEE transactions on magnetics》2007,43(10):3904-3913
This paper presents a general method for deriving a closed-form solution for precise calculation of the magnetic field around a permanent magnet (PM) or an electromagnet (EM). The method, referred here as distributed multipole (DMP) modeling, inherits many advantages of the dipole model originally conceptualized in the context of physics, but provides an effective means to account for the shape and magnetization of the physical magnet. Three examples are given to illustrate the procedure of developing a DMP model, which derives an appropriate set of distributed dipoles from a limited set of known field points, for a general cylindrical PM, a customized PM, and a multilayer coil. The DMP modeling method has been validated by comparing simulated fields and calculated forces against data obtained experimentally and numerically; the comparisons show excellent agreement. Finally, we illustrate how the closed-form DMP models can offer an inexpensive means to visualize the effect of the EM fields on the leakage and unexpected flux paths, which have significant influences on the magnetic torque of a spherical motor. 相似文献
123.
The SrRuO3 thin films were grown on amorphous fused silica and (100) single crystal LaAlO3 substrates by pulsed laser deposition method. On fused silica substrates, polycrystalline SrRuO3 thin film was obtained and below the crystallization temperature, SrRuO3 thin films show an amorphous phase. For the case of epitaxial growth on (100) single crystal LaAlO3 substrate, the crystallization temperature of SrRuO3 thin film was increased by ∼ 100 °C indicating that additional energy is necessary in order to obtain the epitaxial thin film. By using the eclipse method and the control of substrate temperature, the variations of surface morphologies and grain size were observed by atomic force microscope. Below the crystallization temperature, amorphous SrRuO3 thin film shows hopping transport property of an insulator. 相似文献
124.
Zang‐Hee Cho Young‐Don Son Hang‐Keun Kim Kyoung‐Nam Kim Se‐Hong Oh Jae‐Yong Han In‐Ki Hong Young‐Bo Kim 《International journal of imaging systems and technology》2007,17(4):252-265
A PET‐MRI fusion system is developed for molecular‐genetic imaging. The purpose of the system is to obtain images of the in‐vivo human brain using two high‐end imaging devices, an advanced PET and an ultrahigh‐field MRI. These are the HRRT‐PET, a high‐resolution research tomograph dedicated to brain imaging on the molecular level, and the 7.0‐T MRI, an ultrahigh field version used for morphological imaging. HRRT‐PET delivers high‐resolution molecular imaging with a resolution down to 2.5 mm FWHM, which is currently the highest spatial resolution available for the observation of the human brain's molecular activities, including enzymes and receptors, which are manipulated genetically, such as reporter genes and probes. The 7.0‐T MRI began to reveal submillimeter resolution images of the cortical as well as deep brain areas, down to 250 μm, which allows us to visualize the fine details of the cortical and brainstem areas, including the line of Gennari in the visual cortex and the corticospinal tracts in the pontine area. The current PET‐MRI fusion imaging system produces the highest quality images of molecular and genetic activities of the human brain in vivo. It is starting to provide many answers to the key questions about the neurological diseases. Some of these start providing answers to many cognitive neuroscience problems with clear molecular and genetic bases. There is great potential in the PET‐MRI for early diagnosis of cancers as well as other neurological diseases, which we were previously unable to diagnose, such as microscopic molecular changes that occur in Parkinson's and Alzheimer's diseases. © 2007 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 17, 252–265, 2007 相似文献
125.
Jong-Ho Lee Kwang Nyeon Kim Ji-Won Son Joosun Kim Byung-Kook Kim Hae-Weon Lee Jooho Moon 《Journal of Materials Science》2007,42(6):1866-1871
LSGM is known to have very serious interfacial reactivity with other unit cell components even though it is one of the most
favorable solid electrolytes for intermediate-temperature SOFCs. Above all, the formation of a La-deficient La-Sr-Ga-O phase
at the LSGM/NiO or the LSGM/CeO2 interface is most problematic in LSGM-based SOFCs due to the very resistive nature of its electrical property in fuel cell
operating conditions. In this study, we investigated the interfacial reactions in LSGM-based SOFCs under various fabrication
conditions, in order to discern a method to either avoid or diminish the undesirable influence of these interfacial reactions.
Microstructural evolution due to the chemical reactions between the anode and electrolyte layer were characterized with an
Environmental Scanning Electron Microscopy (ESEM-PHILIPS XL-30) and an Energy Dispersive X-ray (EDX-Link XL30) analysis. The
spatial distributions of each constituent element at the interfaces were thoroughly investigated with an Electron Probe Micro-Analyzer
(EPMA-JEOL. JXA-8600). 相似文献
126.
In Sik Yu Hyun Soo Woo Hyoung Il Son Woojin Ahn Hoeryong Jung 《Advanced Robotics》2013,27(18):2115-2143
This paper presents a new design and analysis of a haptic interface for a gastrointestinal endoscopy simulation. The gastrointestinal endoscopy is a procedure in which the digestive tract and organs of a patient are diagnosed and treated using a long and flexible endoscope. The developed haptic interface incorporates two degrees of freedom (DOF), each of which is necessary to describe the movements of an endoscope during the actual endoscopy procedures. The haptic interface has a translational motion mechanism to implement the insertion movement of the endoscope, and a rotational motion mechanism to implement the rotational movement of the endoscope. The endoscope included in the haptic interface is supported by a folding guide to prevent the endoscope from buckling. Force feedback in each direction is provided by wire-driven mechanisms. The developed haptic interface has a workspace, sensitivity, and maximum attainable force and torque enough to simulate the endoscopy procedures such as colonoscopy, upper GI (gastrointestinal) endoscopy, and endoscopic retrograde cholangiopancreatography (ERCP). The developed haptic interface is applied to implementation of a colonoscopy simulation. Performance including force bandwidth is evaluated through experiments and simulation. 相似文献
127.
Young-Boo Son Seung Hoon Shin Sang-Hoon Ji Yeon-Sun Choi Ja Choon Koo 《Microsystem Technologies》2013,19(9-10):1433-1440
Misalignment of mechanical rolling elements such as belt and pulley causes catastrophic malfunctions of high speed paper feeding systems like automated teller machines (ATMs), printers, and copy machines. A combination of a crown pulley and a belt can be an effective self-alignment mechanism for the systems. In this paper, an equation of motion of the belt and pulley system is driven, verification tests are carried out, and a design improvement strategy is suggested for high speed paper media transport systems. 相似文献
128.
This paper proposes a coordinated control scheme of an SVC (static VAr compensator) and a ULTC (under load tap changer) of a distribution substation to obtain a larger operating margin of SVC for emergency control. The conventional method can cause a lack of operating margin of SVCs in some conditions. It, however, is important to secure an operating margin for emergencies. In the proposed coordinated control system, SVC controls the voltage and ULTC responds to the SVC compensation value based on the relation between SVC compensation and ULTC tap position. In order to reserve the operating margin of the SVC, the time delay of ULTC is adaptively changed according to the operating condition of the SVC. Numerical simulations verify that the proposed system could increase the operating margin of SVC while improving the quality of load voltage 相似文献
129.
The effect of injection molding conditions and reactive compatibilization on the morphology of maleic anhydryde‐modified poly(phenylene oxide)/polyamide‐6 blends was investigated. The injection flow rate primarily influenced the position of the subskin layer, and the injection temperature affected the aspect ratio of the dispersed phase. A reduction of the sue of the dispersed phase occured during the converging flow in the barrel‐to‐sprue zone. The reactive compatibilization reduced the flow induced deformation, the coalescence and the breakup of particles and improved the dispersion of the minor phase. 相似文献
130.
Byung-Kook Hwang Hyuk-Soo Son Jae-Hyuk Kim Chang Hoon Ahn Chung-Hak Lee Jae-Yoon Song Young-Hyun Ra 《Journal of Industrial and Engineering Chemistry》2010,16(4):602-608
We have investigated the decomposition of excess sludge generated in a membrane bioreactor using a turbulent jet flow ozone contactor (TJC), which induced both hydrodynamic cavitation and ozonation reactions. We monitored the effects of various TJC operating parameters on the properties of the sludge, including the particle sizes, the particle size distribution, and the levels of soluble COD, total COD, and mixed liquor suspended solids. The TJC enhanced the degree of sludge reduction while consuming less energy, relative to conventional ozonation treatment systems, because of the synergic effects of hydrodynamic cavitation and ozonation. The hydrodynamic cavitation generated in the TJC increased the ozone mass transfer efficiency, which in turn promoted the rate of disintegration and solubilization of the sludge particles. 相似文献