101
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Saam T, Hatsukami TS, Underhill H, Chu B, Takaya N, Cai J, Yarnykh V, Kerwin WS, Yuan C. Sind quantitative Messungen Atherosklerotischer Plaques mittels 1.5T Siemens-, GE- und Phillips MR-Tomographen identisch? ROFO-FORTSCHR RONTG 2006. [DOI: 10.1055/s-2006-940902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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102
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Saam T, Yuan C, Chu B, Takaya N, Underhill H, Cai J, Tran N, Polissar NL, Hatsukami TS. Einfluss von Risikofaktoren auf die Progression Atherosklerotischer Plaques in der A. Karotis: Eine nichtinvasive MRT-Studie. ROFO-FORTSCHR RONTG 2006. [DOI: 10.1055/s-2006-941071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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103
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Burger C, Zhou H, Hsiao BS, Chu B. Theoretical treatment and practical aspects of systems with preferred orientation. Acta Crystallogr A 2005. [DOI: 10.1107/s0108767305095504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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104
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Zapata-Espinosa A, Medellín-Rodríguez FJ, Stribeck N, Almendarez-Camarillo A, Vega-Díaz S, Hsiao BS, Chu B. Complex Isothermal Crystallization and Melting Behavior of Nylon 6 Nanoclay Hybrids. Macromolecules 2005. [DOI: 10.1021/ma050247m] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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105
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Kampschulte A, Ferguson MS, Kerwin WS, Polissar NL, Chu B, Saam T, Hatsukami TS, Yuan C. Differentiation of Intraplaque Versus Juxtaluminal Hemorrhage/Thrombus in Advanced Human Carotid Atherosclerotic Lesions by In Vivo Magnetic Resonance Imaging. Circulation 2004; 110:3239-44. [PMID: 15533871 DOI: 10.1161/01.cir.0000147287.23741.9a] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Intraplaque hemorrhage and juxtaluminal hemorrhage/thrombus may differ in cause and clinical implications. This study tested the hypothesis that MRI can distinguish between intraplaque hemorrhage and juxtaluminal hemorrhage/thrombus and investigated the association between hemorrhage and underlying lesion types.
Methods and Results—
Twenty-six patients scheduled for carotid endarterectomy were imaged with a 1.5-T GE scanner by a multicontrast-weighted MRI technique. Hemorrhages were identified with previously established MRI criteria, and differentiations were made between intraplaque and juxtaluminal hemorrhage/thrombus. Corresponding histology was used to confirm the magnetic resonance findings. Tissues underlying areas of hemorrhage/thrombus were histologically categorized according to modified American Heart Association criteria. Of 190 matched sections, 140 contained areas of hemorrhage by histology, of which MRI correctly detected 134. The sensitivity and specificity for MRI to correctly identify cross sections that contained hemorrhage were 96% and 82%, respectively. Furthermore, MRI was able to distinguish juxtaluminal hemorrhage/thrombus from intraplaque hemorrhage with an accuracy of 96%. The distribution of lesion types underlying hemorrhages differed significantly (
P
=0.004). Intraplaque hemorrhage had an underlying lipid-rich type IV/V lesion in 55% of histological sections, whereas juxtaluminal hemorrhage/thrombus had an underlying calcified lesion type VII in 70% of sections.
Conclusions—
In vivo high-resolution MRI can detect and differentiate intraplaque hemorrhage from juxtaluminal hemorrhage/thrombus with good accuracy. The association of hemorrhage and lesion types suggests potential differences in origin. Noninvasive MRI therefore provides a possible tool for prospectively studying differences in origin of plaque hemorrhage and the association of plaque progression and instability.
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106
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Gelfer M, Burger C, Fadeev A, Sics I, Chu B, Hsiao BS, Heintz A, Kojo K, Hsu SL, Si M, Rafailovich M. Thermally induced phase transitions and morphological changes in organoclays. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:3746-58. [PMID: 15875410 DOI: 10.1021/la035361h] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Thermal transitions and morphological changes in Cloisite organoclays were investigated by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, and in situ simultaneous small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) over the temperature range of 30-260 degrees C. On the basis of DSC and FTIR results, the surfactant component in organoclays was found to undergo a melting-like order-disorder transition between 35 and 50 degrees C. The transition temperatures of the DSC peaks (Ttr) in the organoclays varied slightly with the surfactant content; however, they were significantly lower than the melting temperature of the free surfactant (dimethyldihydrotallowammonium chloride; Tm = 70 degrees C). FTIR results indicated that within the vicinity of Ttr, the gauche content increased significantly in the conformation of surfactant molecules, while WAXD results did not show any change in three-dimensional ordering. Multiple scattering peaks were observed in SAXS profiles. In the SAXS data acquired below Ttr, the second scattering peak was found to occur at an angle lower than twice that of the first peak position (i.e., nonequidistant scattering maxima). In the data acquired above Ttr, the second peak was found to shift toward the equidistant position (the most drastic shift was seen in the system with the highest surfactant content). Using a novel SAXS modeling technique, we suggest that the appearance of nonequidistant SAXS maxima could result from a bimodal layer thickness distribution of the organic layers in organoclays. The occurrence of the equidistant scattering profile above Ttr could be explained by the conversion of the bimodal distribution to the unimodal distribution, indicating a redistribution of the surfactant that is nonbounded to the clay surface. At temperatures above 190 degrees C, the scattering maxima gradually broadened and became nonequidistant again but having the second peak shifted toward a scattering angle higher than twice the first peak position. The changes in SAXS patterns above 190 degrees C could be attributed to the collapse of organic layers due to desorption and/or degradation of surfactant component, which was supported by the TGA data.
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107
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Dembo AT, Yakunin AN, Zaitsev VS, Mironov AV, Starodoubtsev SG, Khokhlov AR, Chu B. Regular microstructures in gel-surfactant complexes: Influence of water content and comparison with the surfactant structure in water. ACTA ACUST UNITED AC 2003. [DOI: 10.1002/polb.1996.953] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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108
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Koga T, Seo YS, Shin K, Zhang Y, Rafailovich MH, Sokolov JC, Chu B, Satija SK. The Role of Elasticity in the Anomalous Swelling of Polymer Thin Films in Density Fluctuating Supercritical Fluids. Macromolecules 2003. [DOI: 10.1021/ma021265w] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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109
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Luu YK, Kim K, Hsiao BS, Chu B, Hadjiargyrou M. Development of a nanostructured DNA delivery scaffold via electrospinning of PLGA and PLA-PEG block copolymers. J Control Release 2003; 89:341-53. [PMID: 12711456 DOI: 10.1016/s0168-3659(03)00097-x] [Citation(s) in RCA: 469] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The present work utilizes electrospinning to fabricate synthetic polymer/DNA composite scaffolds for therapeutic application in gene delivery for tissue engineering. The scaffolds are non-woven, nano-fibered, membranous structures composed predominantly of poly(lactide-co-glycolide) (PLGA) random copolymer and a poly(D,L-lactide)-poly(ethylene glycol) (PLA-PEG) block copolymer. Release of plasmid DNA from the scaffolds was sustained over a 20-day study period, with maximum release occurring at approximately 2 h. Cumulative release profiles indicated amounts released were approximately 68-80% of the initially loaded DNA. Variations in the PLGA to PLA-PEG block copolymer ratio vastly affected the overall structural morphology, as well as both the rate and efficiency of DNA release. Results indicated that DNA released directly from these electrospun scaffolds was indeed intact, capable of cellular transfection, and successfully encoded the protein beta-galactosidase. When tested under tensile loads, the electrospun polymer/DNA composite scaffolds exhibited tensile moduli of approximately 35 MPa, with approximately 45% strain initially. These values approximate those of skin and cartilage. Taken together, this work represents the first successful demonstration of plasmid DNA incorporation into a polymer scaffold using electrospinning.
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110
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Chu B, Hatsukami T, Polissar N, Zhao X, Kraiss L, Parker D, Waterton J, Raichlen J, Hamar W, Yuan C. 3P-0871 Use of magnetic resonance imaging to assess carotid atherosclerotic lesion distribution. ATHEROSCLEROSIS SUPP 2003. [DOI: 10.1016/s1567-5688(03)91089-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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111
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Chu B, Hatsukami T, Zhao X, Polissar N, Waterton J, Raichlen J, Hamar W, Yuan C. 3P-0872 Reproducibility of carotid atherosclerotic lesion type determination using high-resolution magnetic resonance imaging. ATHEROSCLEROSIS SUPP 2003. [DOI: 10.1016/s1567-5688(03)91090-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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112
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Chu B. Factors affecting pre-concentration of tocopherols and tocotrienols from palm fatty acid distillate by lipase-catalysed hydrolysis. Food Chem 2002. [DOI: 10.1016/s0308-8146(02)00177-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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113
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Chu B, Liu T, Wan Q, Burger C. Polymer-assisted formation of polyoxomolybdates. Acta Crystallogr A 2002. [DOI: 10.1107/s0108767302086099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023] Open
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114
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Katz MG, Chu B, McLachlan R, Alexopoulos NI, de Kretser DM, Cram DS. Genetic follow-up of male offspring born by ICSI, using a multiplex fluorescent PCR-based test for Yq deletions. Mol Hum Reprod 2002; 8:589-95. [PMID: 12029079 DOI: 10.1093/molehr/8.6.589] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
De-novo deletions involving AZFa, b, c and d are one of the most common chromosomal aberrations in man resulting in defective spermatogenesis and male infertility. Currently, Yq deletion screening involves either single or multiplex PCR using Y-specific sequence tagged site markers and the subsequent analysis of the amplification products on ethidium bromide-stained agarose gels. To improve the practicality of routine and high throughput Yq testing, we have developed a more sensitive multiplex fluorescent (FL)-PCR screening system using genomic DNA extracted from cheek buccal cells as a readily available PCR template. For genetic follow-up studies of ICSI-conceived children, we also developed a DNA fingerprinting system based on the co-amplification of four highly polymorphic markers to validate family samples and detect any potential extraneous DNA contamination that could cause a misdiagnosis. Multiplex FL-PCR analysis of buccal cell DNA from two infertile men who conceived three sons by ICSI demonstrated that their Yq deletions were vertically transmitted. Fine mapping with additional Yq markers revealed identical deletion endpoints involving the loss of AZFdc sequences. This firstly indicates that the extent of the Yq deletion was unchanged on ICSI transmission and secondly supports the view that AZFdc deletions may arise by a common de-novo event. Analysis of paternal, maternal and sibling DNA fingerprints showed the co-inheritance of parental alleles by each male child and confirmed the expected relationship between each family member. The application of these new FL-PCR based screening tests in genetic follow-up studies will assist in confirming transmission of specific genetic defects to male offspring conceived by ICSI and provide a basis for genetic counselling and potential treatment options as these boys approach sexual maturity.
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115
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Bucher J, Diamond RM, Chu B. Selectivity in heterovalent anion exchange. Ion pairing vs. ion hydration. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100661a021] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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116
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He MJ, Kubota K, Pope J, Chu B. Static and dynamical properties of polystyrene in carbon tetrachloride. 3. Effects of freezing on solution properties. Macromolecules 2002. [DOI: 10.1021/ma00230a089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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117
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Chu B, Onclin M, Ford JR. Laser light scattering characterization of polyethylene in 1,2,4-trichlorobenzene. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j150670a019] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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118
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119
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Chu B. CRITICAL OPALESCENCE OF METHANOL—CYCLOHEXANE, TRANSMISSION MEASUREMENTS. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100804a006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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120
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Mandelkern L, Alamo RG, Sokolov EL, Li Y, Chu B. Small-Angle X-ray Scattering of n-Hexacontane as a Function of Temperature. Macromolecules 2002. [DOI: 10.1021/ma00086a054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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121
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Fytas G, Dorfmueller T, Lin YH, Chu B. Photon correlation spectroscopy of bulk siloxane polymers. Macromolecules 2002. [DOI: 10.1021/ma50005a039] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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122
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Chu B, Gulari E. Polymer Diffusion in a Dilute Solution. 2. Poly[bis(m-chlorophenoxy)phosphazene] in Chloroform. Macromolecules 2002. [DOI: 10.1021/ma60069a020] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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123
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Lin YH, Chu B. Observation of a Pseudo-Transition Phenomenon between Dilute and Semidilute Regimes in a Polymer Solution. Macromolecules 2002. [DOI: 10.1021/ma60076a055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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124
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125
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Debye P, Chu B. SPECTROPHOTOMETRY AND LIGHT SCATTERING ON SUPPORTED PLATINUM1,2. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100812a014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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