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Papers by Chen Fang
Journal of Systems and Software, 1999
There are more and more COSS (Common Object Service Specification) on CORBA (Common Object Reques... more There are more and more COSS (Common Object Service Specification) on CORBA (Common Object Request Broker Architecture) that is announced by the OMG (Object Management Group), but no common specijication about fault-tolerance exists now. In this paper, we propose a "warm stand-by" replication approach. When an object (primary object) is invoked, it will invoke a secondary object, and the primary object will log the messages and checkpoint the state to the secondary object periodically. If the primary object fails, the secondary object can take over by way of client executing a few operations to change secondary object's mode to primary's. Following the style of COSS, we define four interfaces and provide class implementations that can help programmers write programs with faulttolerant capability. The whole model has been implemented on Orbix, which is a full implementation of CORBA specification.
Small, 2006
We report the development of a biostable methotrexate-immobilized iron oxide nanoparticle drug ca... more We report the development of a biostable methotrexate-immobilized iron oxide nanoparticle drug carrier that may potentially be used for realtime monitoring of drug delivery through magnetic resonance imaging. Methotrexate (MTX) was immobilized on the nanoparticle surface via a poly(ethylene glycol) self-assembled monolayer (PEG SAM). The cytotoxicity of the nanoparticle-drug conjugate (NP-PEG-MTX) to target cells was studied with 9L glioma cells. Cellular uptake experiments showed that the uptake of NP-PEG-MTX conjugates by glioma cells was considerably higher than that of control nanoparticles. Magnetic resonance imaging in 9L cells cultured with NP-PEG-MTX of various concentrations showed significant contrast enhancement. NP-PEG-MTX demonstrated higher cytotoxicity in 9L cells to free MTX in vitro. Leucovorin, an MTX antidote, was used to rescue the cells that had been exposed to NP-PEG-MTX or free MTX, and the experiment verified the biocompatibility of NP-PEG-MTX conjugates and the MTX on NP-PEG-MTX conjugates to be the true source of the cytotoxicity to the target cells. TEM results showed that NP-PEG-MTX conjugates were internalized into the 9L cellular cytoplasm and retained its crystal structure therein for up to 144 h, as identified by electron diffraction. This prolonged particle retention may allow physicians to image tumor cells exposed to the NP-PEG-MTX conjugate over an extended therapeutic time course.
Small, 2008
Converging advances in the development of nanoparticle-based imaging probes and improved understa... more Converging advances in the development of nanoparticle-based imaging probes and improved understanding of the molecular biology of brain tumors offer the potential to provide physicians with new tools in the diagnosis and treatment of these deadly diseases. However, the effectiveness of promising nanoparticle technologies is currently limited by insufficient accumulation of these contrast agents within tumors. Here we present a biocompatible nanoprobe composed of a poly (ethylene glycol) (PEG) coated iron oxide nanoparticle that is capable of specifically targeting glioma tumors via the surface-bound targeting peptide, chlorotoxin (CTX). The preferential accumulation of the nanoprobe within gliomas and subsequent magnetic resonance imaging (MRI) contrast enhancement were demonstrated in vitro in 9L cells and in vivo in tumors of a xenograft mouse model. TEM imaging revealed that the nanoprobes were internalized into the cytoplasm of 9L cells and histological analysis of selected tissues indicated no acute toxic effects of these nanoprobes. High-targeting specificity and benign biological response establish this nanoprobe as a potential platform to aid in the diagnosis and treatment of gliomas and other tumors of the neuroectodermal origin.
Journal of Systems and Software, 1999
There are more and more COSS (Common Object Service Specification) on CORBA (Common Object Reques... more There are more and more COSS (Common Object Service Specification) on CORBA (Common Object Request Broker Architecture) that is announced by the OMG (Object Management Group), but no common specijication about fault-tolerance exists now. In this paper, we propose a "warm stand-by" replication approach. When an object (primary object) is invoked, it will invoke a secondary object, and the primary object will log the messages and checkpoint the state to the secondary object periodically. If the primary object fails, the secondary object can take over by way of client executing a few operations to change secondary object's mode to primary's. Following the style of COSS, we define four interfaces and provide class implementations that can help programmers write programs with faulttolerant capability. The whole model has been implemented on Orbix, which is a full implementation of CORBA specification.
Small, 2006
We report the development of a biostable methotrexate-immobilized iron oxide nanoparticle drug ca... more We report the development of a biostable methotrexate-immobilized iron oxide nanoparticle drug carrier that may potentially be used for realtime monitoring of drug delivery through magnetic resonance imaging. Methotrexate (MTX) was immobilized on the nanoparticle surface via a poly(ethylene glycol) self-assembled monolayer (PEG SAM). The cytotoxicity of the nanoparticle-drug conjugate (NP-PEG-MTX) to target cells was studied with 9L glioma cells. Cellular uptake experiments showed that the uptake of NP-PEG-MTX conjugates by glioma cells was considerably higher than that of control nanoparticles. Magnetic resonance imaging in 9L cells cultured with NP-PEG-MTX of various concentrations showed significant contrast enhancement. NP-PEG-MTX demonstrated higher cytotoxicity in 9L cells to free MTX in vitro. Leucovorin, an MTX antidote, was used to rescue the cells that had been exposed to NP-PEG-MTX or free MTX, and the experiment verified the biocompatibility of NP-PEG-MTX conjugates and the MTX on NP-PEG-MTX conjugates to be the true source of the cytotoxicity to the target cells. TEM results showed that NP-PEG-MTX conjugates were internalized into the 9L cellular cytoplasm and retained its crystal structure therein for up to 144 h, as identified by electron diffraction. This prolonged particle retention may allow physicians to image tumor cells exposed to the NP-PEG-MTX conjugate over an extended therapeutic time course.
Small, 2008
Converging advances in the development of nanoparticle-based imaging probes and improved understa... more Converging advances in the development of nanoparticle-based imaging probes and improved understanding of the molecular biology of brain tumors offer the potential to provide physicians with new tools in the diagnosis and treatment of these deadly diseases. However, the effectiveness of promising nanoparticle technologies is currently limited by insufficient accumulation of these contrast agents within tumors. Here we present a biocompatible nanoprobe composed of a poly (ethylene glycol) (PEG) coated iron oxide nanoparticle that is capable of specifically targeting glioma tumors via the surface-bound targeting peptide, chlorotoxin (CTX). The preferential accumulation of the nanoprobe within gliomas and subsequent magnetic resonance imaging (MRI) contrast enhancement were demonstrated in vitro in 9L cells and in vivo in tumors of a xenograft mouse model. TEM imaging revealed that the nanoprobes were internalized into the cytoplasm of 9L cells and histological analysis of selected tissues indicated no acute toxic effects of these nanoprobes. High-targeting specificity and benign biological response establish this nanoprobe as a potential platform to aid in the diagnosis and treatment of gliomas and other tumors of the neuroectodermal origin.