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Search Results: 1 - 10 of 38237 matches for " Chia-Feng Lo "
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Optimization of Lipase Production by Burkholderia sp. Using Response Surface Methodology
Chia-Feng Lo,Chi-Yang Yu,I-Ching Kuan,Shiow-Ling Lee
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms131114889
Abstract: Response surface methodology (RSM) was employed to optimize the extracellular lipase production by Burkholderia sp. HL-10. Preliminary tests showed that olive oil, tryptone and Tween-80 exhibited significant effects on the lipase production. The optimum concentrations of these three components were determined using a faced-centered central composite design (FCCCD). The analysis of variance revealed that the established model was significant ( p < 0.01). The optimized medium containing 0.65% olive oil ( v/ v), 2.42% tryptone ( w/ v) and 0.15% Tween-80 ( v/ v) resulted in a maximum activity of 122.3 U/mL, about three fold higher than that in basal medium. Approximately 99% of validity of the predicted value was achieved.
Multilepton Higgs Decays through the Dark Portal
Chia-Feng Chang,Ernest Ma,Tzu-Chiang Yuan
Physics , 2013, DOI: 10.1007/JHEP03(2014)054
Abstract: The U(1)_D gauge sector containing one dark Higgs boson h_D and one dark photon \gamma_D may be explored through the decays of the 126 GeV particle discovered at the Large Hadron Collider (LHC), assumed here as the heavier mass eigenstate h_1 in the mixing of the standard model h with h_D. The various decays of h_1 to \gamma_D \gamma_D, h_2 h_2, h_2 \gamma_D \gamma_D and h_2 h_2 h_2 would yield multilepton final states through the mixing of \gamma_D with the photon and the decay h_2 \to \gamma_D \gamma_D, where h_2 is the lighter dark Higgs. Future searches for signals of multilepton jets at the LHC may reveal the existence of this possible dark sector governed simply by the original Abelian Higgs model.
Attention Drawing of Movie Trailers Revealed by Electroencephography Using Sample Entropy  [PDF]
Po-Shan Wang, Shang-Ran Huang, Chao-Wen Tsai, Chia-Feng Lu, Shin Teng, C.-I. Hung, Yu-Te Wu
Journal of Biosciences and Medicines (JBM) , 2014, DOI: 10.4236/jbm.2014.24002
Abstract:

A movie trailer is a common advertising tool in the entertainment industry. Detection of a viewer’s brain responses to a movie trailer can help film producers to tailor a more appealing trailer of a movie. In this study, we acquired electroencephalographic (EEG) signals from subjects when they watched movie trailers (labeled as Movie session), and compared with their resting state session (labeled as Resting session) or when they watch nature scenes (labeled as Nature session). We used Sample Entropy (SampEn) to analyze the EEG signals between different sessions. Results showed that the complexity ratios at Fp1, Fp2 and Fz channels derived from Movie session were significantly lower than that in Resting state or when subjects watched Nature session (p < 0.001). Our results suggest that the brain status can affect the complexity of their EEG. Further, the attraction of attention of a movie trailer can be observed from the change of EEG.

Blind Source Separation of Hemodynamics from Magnetic Resonance Perfusion Brain Images Using Independent Factor Analysis
Yen-Chun Chou,Chia-Feng Lu,Wan-Yuo Guo,Yu-Te Wu
International Journal of Biomedical Imaging , 2010, DOI: 10.1155/2010/360568
Abstract: Perfusion magnetic resonance brain imaging induces temporal signal changes on brain tissues, manifesting distinct blood-supply patterns for the profound analysis of cerebral hemodynamics. We employed independent factor analysis to blindly separate such dynamic images into different maps, that is, artery, gray matter, white matter, vein and sinus, and choroid plexus, in conjunction with corresponding signal-time curves. The averaged signal-time curve on the segmented arterial area was further used to calculate the relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), and mean transit time (MTT). The averaged ratios for rCBV, rCBF, and MTT between gray and white matters for normal subjects were congruent with those in the literature. 1. Introduction Dynamic susceptibility-contrast perfusion magnetic resonance (MR) imaging is a commonly used method for the noninvasive assessment of cerebral blood perfusion because of the availability of MR imaging units and lack of exposure to ionizing radiation [1–10]. After a bolus injection of intravascular contrast agent, the passage of bolus induces the susceptibility inhomogeneity, which in turn causes a relative decrease of image intensities of brain tissues from the baseline. Various tissues manifest distinct blood-supply patterns since the contrast agent arrives consecutively, leading to temporal intensity drops at different time instants. Based on the perfusion data, we can calculate the hemodynamic parametric maps, that is, relative cerebral blood volume (rCBV), relative cerebral blood flow (rCBF), and mean transit time (MTT), by employing the indicator dilution theory [11, 12]. This has been used in the assessment of many brain disorders such as tumors [2, 7, 13], stroke [14], infection [15], and moyamoya disease [16, 17]. The estimation of rCBV and rCBF, however, requires arterial concentration of the contrast agent as an arterial input function (AIF). This is a demanding task, and many methods have been proposed to address the issue. Additionally, classification of blood-supply patterns for various tissue types in brain based on bolus transit profiles is essential for the assessment of brain perfusion. Wiart et al. [18] manually selected single or multiple pixels for the tissue of interest and used the averaged temporal profile as a reference in producing a similarity map for segmenting gray matter (GM) and white matter (WM) from perfusion images. This method is advantageous for easy implementation but limited to extraction of a single tissue type per similarity map. If one attempts to
WNT4/β-Catenin Pathway Maintains Female Germ Cell Survival by Inhibiting Activin βB in the Mouse Fetal Ovary
Chia-Feng Liu,Keith Parker,Humphrey H.-C. Yao
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0010382
Abstract: Female germ cells are essential for organogenesis of the ovary; without them, ovarian follicles do not form and functional and structural characteristics of the ovary are lost. We and others showed previously that when either Wnt4 or β-catenin was inactivated in the fetal ovary, female germ cells underwent degeneration. In this study, we set out to understand whether these two factors belong to the same pathway and how they maintain female germ cell survival. We found that activation of β-catenin in somatic cells in the Wnt4 knockout ovary restored germ cell numbers, placing β-catenin downstream of WNT4. In the absence of Wnt4 or β-catenin, female germ cells entered meiosis properly; however, they underwent apoptosis afterwards. Activin βB (Inhbb), a subunit of activins, was upregulated in the Wnt4 and β-catenin knockout ovaries, suggesting that Inhbb could be the cause for the loss of female germ cells, which are positive for activin receptors. Indeed, removal of Inhbb in the Wnt4 knockout ovaries prevented female germ cells from undergoing degeneration. We conclude that WNT4 maintains female germ cell survival by inhibiting Inhbb expression via β-catenin in the somatic cells. Maintenance of female germ cells hinge upon a delicate balance between positive (WNT4 and β-catenin) and negative (activin βB) regulators derived from the somatic cells in the fetal ovary.
Hydrogen Storage in Iron/Carbon Nanopowder Composite Materials: Effect of Varying Spiked Iron Content on Hydrogen Adsorption
Chun-Lin Chu,Chia-Feng Chang,Jiann-Ruey Chen,Yiin-Kuen Fuh
Journal of Nanomaterials , 2013, DOI: 10.1155/2013/742075
Abstract:
A Role for Hedgehog Signaling in the Differentiation of the Insertion Site of the Patellar Tendon in the Mouse
Chia-Feng Liu, Andrew Breidenbach, Lindsey Aschbacher-Smith, David Butler, Christopher Wylie
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0065411
Abstract: Tendons are typically composed of two histologically different regions: the midsubstance and insertion site. We previously showed that Gli1, a downstream effector of the hedgehog (Hh) signaling pathway, is expressed only in the insertion site of the mouse patellar tendon during its differentiation. To test for a functional role of Hh signaling, we targeted the Smoothened (Smo) gene in vivo using a Cre/Lox system. Constitutive activation of the Hh pathway in the mid-substance caused molecular markers of the insertion site, e.g. type II collagen, to be ectopically expressed or up-regulated in the midsubstance. This was confirmed using a novel organ culture method in vitro. Conversely, when Smo was excised in the scleraxis-positive cell population, the development of the fibrocartilaginous insertion site was affected. Whole transcriptome analysis revealed that the expression of genes involved in chondrogenesis and mineralization was down-regulated in the insertion site, and expression of insertion site markers was decreased. Biomechanical testing of murine adult patellar tendon, which developed in the absence of Hh signaling, showed impairment of tendon structural properties (lower linear stiffness and greater displacement) and material properties (greater strain), although the linear modulus of the mutant group was not significantly lower than controls. These studies provide new insights into the role of Hh signaling during tendon development.
Hemodynamic Segmentation of Brain Perfusion Images with Delay and Dispersion Effects Using an Expectation-Maximization Algorithm
Chia-Feng Lu, Wan-Yuo Guo, Feng-Chi Chang, Shang-Ran Huang, Yen-Chun Chou, Yu-Te Wu
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0068986
Abstract: Automatic identification of various perfusion compartments from dynamic susceptibility contrast magnetic resonance brain images can assist in clinical diagnosis and treatment of cerebrovascular diseases. The principle of segmentation methods was based on the clustering of bolus transit-time profiles to discern areas of different tissues. However, the cerebrovascular diseases may result in a delayed and dispersed local perfusion and therefore alter the hemodynamic signal profiles. Assessing the accuracy of the segmentation technique under delayed/dispersed circumstance is critical to accurately evaluate the severity of the vascular disease. In this study, we improved the segmentation method of expectation-maximization algorithm by using the results of hierarchical clustering on whitened perfusion data as initial parameters for a mixture of multivariate Gaussians model. In addition, Monte Carlo simulations were conducted to evaluate the performance of proposed method under different levels of delay, dispersion, and noise of signal profiles in tissue segmentation. The proposed method was used to classify brain tissue types using perfusion data from five normal participants, a patient with unilateral stenosis of the internal carotid artery, and a patient with moyamoya disease. Our results showed that the normal, delayed or dispersed hemodynamics can be well differentiated for patients, and therefore the local arterial input function for impaired tissues can be recognized to minimize the error when estimating the cerebral blood flow. Furthermore, the tissue in the risk of infarct and the tissue with or without the complementary blood supply from the communicating arteries can be identified.
Sculpting the Intrinsic Modular Organization of Spontaneous Brain Activity by Art
Chia-Shu Lin, Yong Liu, Wei-Yuan Huang, Chia-Feng Lu, Shin Teng, Tzong-Ching Ju, Yong He, Yu-Te Wu, Tianzi Jiang, Jen-Chuen Hsieh
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0066761
Abstract: Artistic training is a complex learning that requires the meticulous orchestration of sophisticated polysensory, motor, cognitive, and emotional elements of mental capacity to harvest an aesthetic creation. In this study, we investigated the architecture of the resting-state functional connectivity networks from professional painters, dancers and pianists. Using a graph-based network analysis, we focused on the art-related changes of modular organization and functional hubs in the resting-state functional connectivity network. We report that the brain architecture of artists consists of a hierarchical modular organization where art-unique and artistic form-specific brain states collectively mirror the mind states of virtuosos. We show that even in the resting state, this type of extraordinary and long-lasting training can macroscopically imprint a neural network system of spontaneous activity in which the related brain regions become functionally and topologically modularized in both domain-general and domain-specific manners. The attuned modularity reflects a resilient plasticity nurtured by long-term experience.
Cortical Shape and Curvedness Analysis of Structural Deficits in Remitting and Non-Remitting Depression
Yuan-Lin Liao, Po-Shan Wang, Chia-Feng Lu, Chih-I Hung, Cheng-Ta Li, Ching-Po Lin, Jen-Chuen Hsieh, Tung-Ping Su, Yu-Te Wu
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0068625
Abstract: In morphometric neuroimaging studies, the relationship between brain structural changes and the antidepressant treatment response in patients with major depressive disorder has been explored to search depression-trait biomarkers. Although patients were treated with serotonin-related drugs, whether the same treatment resulted in remission and non-remission in depressed patients is currently under investigation. We recruited 25 depressed patients and 25 healthy controls and acquired volumetric magnetic resonance imaging of each participant. We used the shape index and curvedness to classify cortical shapes and quantify shape complexities, respectively, in studying the pharmacological effect on brain morphology. The results showed that different regions of structural abnormalities emerged between remitting and non-remitting patients when contrasted with healthy controls. In addition to comparing structural metrics in each cortical parcellation, similar to the traditional voxel-based morphometric method, we highlighted the importance of structural integrity along the serotonin pathway in response to medication treatment. We discovered that disrupted serotonin-related cortical regions might cause non-remission to antidepressant treatment from a pharmacological perspective. The anomalous areas manifested in non-remitting patients were mainly in the frontolimbic areas, which can be used to differentiate remitting from non-remitting participants before medication treatment. Because non-remission is the failure to respond to treatment with serotonin-related drugs, our method may help clinicians choose appropriate medications for non-remitting patients.
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