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    Haiyan Guan

    ... Kaiping Yang, Laura Julan, Fran Rubio, Anju Sharma, and Haiyan Guan. ... Birth Defects Res C Embryo Today 72: 361–370, 2004.[CrossRef][Medline]; McTernan CL, Draper N, Nicholson H, Chalder SM, Driver P, Hewison M, Kilby MD, and... more
    ... Kaiping Yang, Laura Julan, Fran Rubio, Anju Sharma, and Haiyan Guan. ... Birth Defects Res C Embryo Today 72: 361–370, 2004.[CrossRef][Medline]; McTernan CL, Draper N, Nicholson H, Chalder SM, Driver P, Hewison M, Kilby MD, and Stewart PM. ...
    Rapid texture mapping of buildings is a key aspect for reconstruction of 3D city landscapes. An effective approach by the way of coarse-to-fine 3D building model generation by integration of LIDAR and multiple overlap images is proposed.... more
    Rapid texture mapping of buildings is a key aspect for reconstruction of 3D city landscapes. An effective approach by the way of coarse-to-fine 3D building model generation by integration of LIDAR and multiple overlap images is proposed. Classification and segmentation can be processed by combined multi-spectral information which is provided by color aerial image and geometric information from multi-return laser scanned data. A connected graph of the segment label image has to be created to derive the neighborhood relation of the planar segments. A line segment matching, based on geometry and chromatic constraint, is applied for automatically getting the corresponding line features in multi target images. Hypotheses for polyhedral surfaces are selected using topological relations and verified using geometry.
    One of the dominant effects of glucocorticoids in triggering parturition in certain animal species is to drive the placental conversion of progesterone to estrogen. However, in the human placenta, estrogen is formed using... more
    One of the dominant effects of glucocorticoids in triggering parturition in certain animal species is to drive the placental conversion of progesterone to estrogen. However, in the human placenta, estrogen is formed using dehydroepiandrosterone from the fetal adrenal glands rather than progesterone as precursor. Although aromatization of dehydroepiandrosterone is crucial in estrogen synthesis in human placenta, it is not known whether glucocorticoids affect aromatase expression. Human term placental syncytiotrophoblasts were used to examine the effect of cortisol on aromatase expression. The signaling pathway and transcription factors involved were identified in this study. Results showed that cortisol induced aromatase expression in a concentration-dependent manner, which was mediated indirectly by glucocorticoid receptor and required the participation of other proteins. The induction of aromatase by cortisol could be blocked by either specificity protein 1 (Sp1) antagonist mithramycin or knockdown of Sp1 expression. The induction of aromatase and Sp1 by cortisol could be prevented by inhibitors of the cAMP pathway, whereas activators of the cAMP pathway induced Sp1 and aromatase expression as well as Sp1 binding to aromatase promoter. Concomitantly, cortisol treatment and activation of the cAMP pathway led to increased acetylation and decreased methylation of histone 3 at the aromatase promoter. In conclusion, cortisol stimulates aromatase expression through the cAMP/Sp1 pathway in human placental syncytiotrophoblasts. These findings reveal a novel role of cortisol in increasing the local level of estrogen within the placenta that would help transform the myometrium to a contractile state, thereby contributing to a cascade of events leading to human parturition.
    Rapid texture mapping of buildings is a key aspect for reconstruction of 3D city landscapes. An effective approach by the way of coarse-to-fine 3D building model generation by integration of LIDAR and multiple overlap images is proposed.... more
    Rapid texture mapping of buildings is a key aspect for reconstruction of 3D city landscapes. An effective approach by the way of coarse-to-fine 3D building model generation by integration of LIDAR and multiple overlap images is proposed. Classification and segmentation can be processed by combined multi-spectral information which is provided by color aerial image and geometric information from multi-return laser
    Bisphenol A (BPA) is one of the most prevalent endocrine disrupting chemicals in the environment. Developmental exposure to BPA is known to be associated with liver dysfunction and diseases, such as hepatic steatosis, liver tumors,... more
    Bisphenol A (BPA) is one of the most prevalent endocrine disrupting chemicals in the environment. Developmental exposure to BPA is known to be associated with liver dysfunction and diseases, such as hepatic steatosis, liver tumors, metabolic syndrome, and altered hepatic gene expression, and DNA methylation profiles. However, the effects of BPA on rodent liver development are unknown. The present study was undertaken to address this important question using the mouse as an experimental model. Pregnant mice were exposed to BPA via diet from embryonic day 7.5 (E7.5) to E18.5. At E18.5, fetal livers were collected, and analyzed for changes in the expression of key hepatocyte maturation markers. We found the following significant alterations in BPA-exposed female but not male fetal livers: (a) levels of the mature hepatocyte markers, albumin and glycogen synthase proteins, were decreased (-65% and -40%, respectively); (b) levels of the immature hepatocyte marker, α-fetoprotein, were increased (+43%); (c) the level of C/EBP-α protein, the master transcription factor essential for hepatocyte maturation, was down-regulated (-50%); and (d) the level of PCNA protein (marker of proliferation) was elevated (+40%), while that of caspase-3 protein and activity (markers of apoptosis) was reduced (-40% and -55%, respectively), suggestive of a perturbed balance between cell proliferation and apoptosis in BPA-exposed female fetuses. Taken together, these findings demonstrate that prenatal exposure to BPA disrupts the mouse fetal liver maturation in a sex-specific manner, and suggest a fetal origin for BPA-induced hepatic dysfunction and diseases.
    Mobile laser scanning (MLS) technologies have been actively studied and implemented over the past decade, as their application fields are rapidly expanding and extending beyond conventional topographic mapping. Trimble’s MX-8, as one of... more
    Mobile laser scanning (MLS) technologies have been actively studied and implemented over the past decade, as their application fields are rapidly expanding and extending beyond conventional topographic mapping. Trimble’s MX-8, as one of the MLS systems in the current market, generates rich survey-grade laser and image data for urban surveying. The objective of this study is to evaluate whether Trimble MX-8 MLS data satisfies the accuracy requirements of urban surveying. According to the formula of geo-referencing, accuracies of navigation solution and laser scanner determine the accuracy of the collected LiDAR point clouds. Two test sites were selected to test the performance of Trimble MX-8. Those extensive tests confirm that Trimble MX-8 offers a very promising tool to survey complex urban areas.
    Research Interests:
    High precision three-dimensional reconstruction and measurement of industrial objects by digital imagery is one of the most active research fields in Computer Vision and Digital Photogrammetry. Due to most of industrial sheet-metal parts... more
    High precision three-dimensional reconstruction and measurement of industrial objects by digital imagery is one of the most active research fields in Computer Vision and Digital Photogrammetry. Due to most of industrial sheet-metal parts are made up of linear features, it is important to extract lines from 2D images accurately. Meanwhile, quality of lines will further to decides on precision of
    One of the dominant effects of glucocorticoids in triggering parturition in certain animal species is to drive the placental conversion of progesterone to estrogen. However, in the human placenta, estrogen is formed using... more
    One of the dominant effects of glucocorticoids in triggering parturition in certain animal species is to drive the placental conversion of progesterone to estrogen. However, in the human placenta, estrogen is formed using dehydroepiandrosterone from the fetal adrenal glands rather than progesterone as precursor. Although aromatization of dehydroepiandrosterone is crucial in estrogen synthesis in human placenta, it is not known whether glucocorticoids affect aromatase expression. Human term placental syncytiotrophoblasts were used to examine the effect of cortisol on aromatase expression. The signaling pathway and transcription factors involved were identified in this study. Results showed that cortisol induced aromatase expression in a concentration-dependent manner, which was mediated indirectly by glucocorticoid receptor and required the participation of other proteins. The induction of aromatase by cortisol could be blocked by either specificity protein 1 (Sp1) antagonist mithramycin or knockdown of Sp1 expression. The induction of aromatase and Sp1 by cortisol could be prevented by inhibitors of the cAMP pathway, whereas activators of the cAMP pathway induced Sp1 and aromatase expression as well as Sp1 binding to aromatase promoter. Concomitantly, cortisol treatment and activation of the cAMP pathway led to increased acetylation and decreased methylation of histone 3 at the aromatase promoter. In conclusion, cortisol stimulates aromatase expression through the cAMP/Sp1 pathway in human placental syncytiotrophoblasts. These findings reveal a novel role of cortisol in increasing the local level of estrogen within the placenta that would help transform the myometrium to a contractile state, thereby contributing to a cascade of events leading to human parturition.
    Maternal cadmium exposure induces fetal growth restriction (FGR), but the underlying mechanisms remain largely unknown. The placenta is the main organ known to protect the fetus from environmental toxins such as cadmium. In this study, we... more
    Maternal cadmium exposure induces fetal growth restriction (FGR), but the underlying mechanisms remain largely unknown. The placenta is the main organ known to protect the fetus from environmental toxins such as cadmium. In this study, we examine the role of the two key placental factors in cadmium-induced FGR. The first is placental enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), which is known to protect the fetus from exposure to high cortisol levels and subsequently FGR, and the second the cadmium binding/sequestering proteins metallotheionein (MT)-I and -II. Using the MT-I/II(-/-) mouse model, pregnant mice were administered cadmium, following which pups and placentas were collected and examined. MT-I/II(-/-) pups exposed to cadmium were significantly growth restricted, but neither placental weight nor 11β-HSD2 was altered. Although cadmium administration did not result in any visible structural changes in the placenta, increased apoptosis was detected in MT-I/II(-/-) placentas following cadmium exposure, with a significant increase in levels of both p53 and caspase 3 proteins. Additionally, glucose transporter (GLUT1) was significantly reduced in MT-I/II(-/-) placentas of pups exposed to cadmium, whereas zinc transporter (ZnT-1) remained unaltered. Taken together, these results demonstrate that MT-I/II(-/-) mice are more vulnerable to cadmium-induced FGR. The present data also suggest that increased apoptosis and reduced GLUT1 expression in the placenta contribute to the molecular mechanisms underlying cadmium-induced FGR.