143 results on '"Chiou R"'
Search Results
2. Acquisition of JAK2, PTPN11, and RAS mutations during disease progression in primary myelodysplastic syndrome
- Author
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Chen, C-Y, Lin, L-I, Tang, J-L, Tsay, W, Chang, H-H, Yeh, Y-C, Huang, C-F, Chiou, R-J, Yao, M, Ko, B-S, Chen, Y-C, Lin, K-H, Lin, D-T, and Tien, H-F
- Published
- 2006
- Full Text
- View/download PDF
3. Modelling the effect of flank wear on machining thrust stability
- Author
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Liang, S. Y., Kwon, Y. K., and Chiou, R. Y.
- Published
- 2004
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4. Antioxidative characteristics of oils in ground pork-fat patties cooked with soy sauce
- Author
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Chiou, R. Y. -Y., Ku, K. -L., Lai, Y. -S., and Chang, L. -G.
- Published
- 2001
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5. Assessment of the CYP3A4-Mediated Drug Interaction Potential of Anacetrapib (ANA), A Potent Cholestery] Ester Transfer Protein (CETP) Inhibitor, In Healthy Subjects: 30
- Author
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Krishna, R, Bergman, A J, Jin, B, Garg, A., Roadcap, B, Chiou, R, Dru, J, Cote, J, Laethem, T, Vets, E, Avery, P, Gottesdiener, K, and Wagner, J A
- Published
- 2008
6. Colour Doppler ultrasonography assessment and a saphenous vein-graft penile venocorporeal shunt for priapism
- Author
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CHIOU, R. K., HENSLEE, D. L., ANDERSON, J. C., and WOBIG, R. K.
- Published
- 1999
7. Pharmacokinetic Interaction Between Indinavir and Rifabutin: PI-66
- Author
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Winchell, G. A., McCrea, J. B., Carides, A., Kusma, S. E., Chiou, R., Deutsch, P., Yeh, K. C., Waldman, S., and Bjornsson, T. D.
- Published
- 1997
8. Immunotherapy for renal cell carcinoma: recent results
- Author
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Lightner, D. J., Vessella, R. L., Chiou, R. K., Palme, D. F., and Lange, P. H.
- Published
- 1986
- Full Text
- View/download PDF
9. Aspects of municipal wastewater reclamation and reuse for future water resource shortages in Taiwan.
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Chiou, R. J., Chang, T. C., and Ouyang, C. F.
- Subjects
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WATER supply management , *WATER reuse , *SEWAGE purification by-products , *WATER conservation , *WATER in agriculture , *LANDSCAPE irrigation , *GOVERNMENT policy - Abstract
The Water Resources Agency (WRA), Ministry of Economic Affairs (MOEA) has predicted that the annual water demand in Taiwan will reach approximately 20 billion m³ by 2021. However, the present water supply is only 18 billion m³ per year. This means that an additional 2 billion m³ have to be developed in the next 17 years. The reuse of treated wastewater effluent from municipal wastewater treatment plants could be one target for the development of new water resources. The responsible government departments already have plans to construct public sewerage systems in order to improve the quality of life of the populace and protect the environment. The treated wastewater effluent from such municipal wastewater treatment plants could be a very stable and readily available secondary type of water resource, different from the traditional types of water resources. The major areas where reclaimed municipal wastewater can be used to replace traditional fresh water resources include agricultural and landscape irrigation, street cleaning, toilet flushing, secondary industrial reuse and environmental uses. However, necessary wastewater reclamation and reuse systems have not yet been established. The requirements for their establishment include water reuse guidelines and criteria, the elimination of health risks ensuring safe use, the determination of the wastewater treatment level appropriate for the reuse category, as well as the development and application of management systems reuse. An integrated system for water reuse would be of great benefit to us all by providing more efficient ways to utilise the water resources. [ABSTRACT FROM AUTHOR]
- Published
- 2007
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- View/download PDF
10. A new device for measuring density of jaw bones.
- Author
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Yang, J, Chiou, R, Ruprecht, A, Vicario, J, MacPhail, L A, and Rams, T E
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FACIAL bones ,JAWS ,BONE densitometry - Abstract
Objectives: The purpose of this project was to develop a lightweight, simple device to evaluate alveolar process bone density using normal intraoral and extraoral imaging procedures. Methods: A simple lightweight device was constructed using barium sulfate as the major radiopaque component. The 5 × 32 × 12 mm³ resin block has eight segments with known densities ranging from 1.304 (g/cm³) to 1.982 (g/cm³). The device was integrated into an XCP unit for standard intraoral radiographs and placed between the jaws for computer aided tomographic imaging. The relationship between the device segment densities and the optical densities of the exposed film was plotted. Results: A linear inverse relationship was found between the device segment densities and optical densities when segment densities were between 1.304 (g/cm³) to 1.882 (g/cm³). However, the relationship was non-linear for segment densities above 1.882 (g/cm³). Conclusions: Normal human bone density is 1.85 (g/cm³), and this densitometer is useful for determination of material densities from 1.304 (g/cm³) to 1.882 (g/cm³). The device may be useful for precise bone density assessment. [ABSTRACT FROM AUTHOR]
- Published
- 2002
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- View/download PDF
11. Proteolysis During the Fermentation of Ethanol-Supplemented Miso.
- Author
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Chiou, R. Y.-Y.
- Subjects
- *
PROTEOLYSIS , *SUCROSE , *FERMENTATION , *SOYBEAN , *ALCOHOL , *MISO - Abstract
Steam-cooked soybeans mixed with rice koji (2:1, w/w) were ground into a fine paste, combined with NaCl (0 to 12.5%) or sucrose (0 to 25%), and supplemented with 15% ethanol for fermentation. The proteolytic activities decreased with NaCl or sucrose; the dose-response effect of NaCl was much more effective than that of sucrose. When fermented with 15% ethanol and 12.5% sucrose at various moisture contents from 30.6 to 53.0%, proteolysis increased proportionally to the increase of moisture content. Mechanical agitation enhanced proteolysis. After 4 w of fermentation, free amino acid contents were higher in products fermented without pH control than in products fermented with pH control. [ABSTRACT FROM AUTHOR]
- Published
- 2001
- Full Text
- View/download PDF
12. THE EFFECTS OF THE FLOW PATTERN ON ORGANIC OXIDATION AND NITRIFICATION IN AERATED SUBMERGE BIOFILTERS.
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Chiou, R.-J., Ouyang, C.-F., and Lin, C.-T.
- Subjects
ORGANIC compounds ,NITROGEN - Abstract
Examines the oxidative efficiencies on organic matter and ammonia nitrogen of different biofilter positions. Biological activities of upflow and downflow patterns; Comparison of the operational characteristics of the two types of biofilters; Activity of the nitrifying autotrophs.
- Published
- 2001
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13. Property Characterization of Peanut Kernels Subjected to Gamma Irradiation and Its Effect on the Outgrowth and Aflatoxin Production by Aspergillus parasiticus.
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CHIOU, R. Y.-Y, LIN, C. M., and SHYU, S.-L.
- Subjects
- *
PEANUTS , *IRRADIATION , *MOLDS (Fungi) , *GERMINATION , *AFLATOXINS - Abstract
BSTRACT Peanut kernels inoculated with Aspergillus parasiticus conidia and uninoculated kernels were gamma irradiated with 0 to 15 kGy using 60Co. Levels of 2.5 and 5.0 KGy were effective in retarding the outgrowth of A. parasiticus and reducing the population of natural mold contaminants. However, elimination of these molds was not achieved. When irradiated with doses higher than 10 KGy, seed germinations were inhibited, changes in proteins were observed and oil stabilities decreased. After 4 wk incubation of the inoculated kernels in a humidified condition, aflatoxins produced by surviving A. parasiticus ranged from 69.12 to 13.48 μg/g depending upon the original irradiation dose. [ABSTRACT FROM AUTHOR]
- Published
- 1990
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14. Comparative effect of famotidine and cimetidine on the pharmacokinetics of theophylline in normal volunteers.
- Author
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Lin, JH, Chremos, AN, Chiou, R, Yeh, KC, and Williams, R
- Abstract
The comparative effect of famotidine or cimetidine on theophylline disposition was determined in healthy volunteers. Cimetidine, but not famotidine, caused a reduction in the rate of elimination of theophylline. The mean total body clearance of theophylline was reduced from 57.6 ml min-1 before cimetidine to 39.5 ml min-1 during cimetidine; and the half-life was prolonged from 8.7 h before cimetidine to 12 h during cimetidine. The volume of distribution and renal excretion of theophylline were not affected by either famotidine or cimetidine. [ABSTRACT FROM AUTHOR]
- Published
- 1987
- Full Text
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15. Monoclonal antibody-targeted radiotherapy of renal cell carcinoma using a nude mouse model.
- Author
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Chiou, Rei K., Vessella, Robert L., Limas, Catherine, Shafer, Rex B., Elson, Michael K., Arfman, Edward W., Lange, Paul H., Chiou, R K, Vessella, R L, Limas, C, Shafer, R B, Elson, M K, Arfman, E W, and Lange, P H
- Published
- 1988
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16. Supplementary health benefits of soy aglycons of isoflavone by improvement of serum biochemical attributes, enhancement of liver antioxidative capacities and protection of vaginal epithelium of ovariectomized rats
- Author
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Lo Dan-Yuan, Hsu Yu-Lin, Lien Tu-Fa, and Chiou Robin YY
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Nutrition. Foods and food supply ,TX341-641 ,Nutritional diseases. Deficiency diseases ,RC620-627 - Abstract
Abstract Background In the literature, supplement of soy aglycons of isoflavone as estrogen agonists in improvement of serum biochemical attributes, liver antioxidative capacities and vaginal epithelium protection has been meagerly investigated. In this study, ovariectomized (OVX) rats were used as an animal model to simulate post-menopausal status. Supplementary health benefits of soy aglycons of isoflavone (SAI) on improvement of growth and serum biochemical attributes, enhancement of liver antioxidation-related capacities and protection of vaginal epithelium of the OVX rats were assessed. Methods As an in vivo study, 30 OVX Sprague-Dawley rats were distributed into OVX (positive control), OVX/LSAI (low SAI group – supplemented with 0.0135% SAI being equivalent to 80 mg per day for a 60 Kg-human), and OVX/HSAI (high SAI group – supplemented with 0.027% SAI) and 10 rats with sham operation as negative control fed with basal diet. Results The average daily gain (ADG), feed intake and feed/gain ratio were higher for the OVX groups than the sham group (P < 0.05). Serum isoflavone concentrations of the OVX rats were increased by SAI supplementation. In comparison, significantly lower serum cholesterol and LDL (low-density lipoprotein) levels, and higher HDL (high-density lipoprotein) levels were detected for the rats of OVX/HSAI group (P < 0.05). SAI supplementation also increased iron chelating ability and decreased values of TBARS (thiobarbituric acid-reactive substance) (P < 0.05) of liver extracts. Liver catalase activity and total antioxidative activity (trolox equivalency) were enhanced by HSAI supplementation (P < 0.05). Decrease of vagina epithelial cellular linings of the OVX rats were noticeably improved by dietary supplementation with SAI. Conclusion Diets supplemented with soy aglycons of isoflavone have conferred health benefits to the OVX rats, in comparison to the sham rats fed with basal diet, by detection of higher serum isoflavone concentrations, significantly lower contents of serum cholesterol and LDL, and higher contents of serum HDL, increased iron chelating ability, lower contents of TBARS (thiobarbituric acid-reactive substance) and enhanced catalase and total antioxidative (as trolox equivalency) activities of the liver extracts, and protection of the epithelial cellular linings of vagina in the former rather than in the latter. This evidences that estrogen-agonist chemoprevention of menopausal-related cardiovascular diseases, decreased liver antioxidative capacities and epithelial degeneration of vagina could be achieved by dietary supplementation with soy aglycons of isoflavone.
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- 2009
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17. The characteristics of nitrogen removal by the biofilter system
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Lin, C. T., Ouyang, C. F., and Chiou, R. J.
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AMMONIA ,BACTERIA ,DENITRIFICATION ,WASTEWATER treatment ,BIOFILTRATION - Abstract
Previous research has shown that nitrogen from municipal wastewater could be eliminated by a biofilter system. In this study a system of combined pre-denitrification/nitrification biofilters was set up. It is to investigate the effect of the hydraulic loading and recycled ratio on nitrogen removal. The characteristics of bacterial activity atdifferent heights is discussed. The experiment shows that longer hydraulic loading would result in better total nitrogen removal. Total nitrogen removal might be not dependent on denitrification but nitrification. Hydraulic loading that affects nitrification might be due to the diffusion of NH3-N from the bulk solution to the inner biofilm. The recycling NO3-N could be completely eliminated in the anoxic biofilter. The operation with longer retention time (HRT of 12 hours) would result in inner denitrification in the aerobic biofilter. Biological activity could be determined by the distribution of bacteria. The specific rates of pollutant decomposition depend on biological activity and effective biological VSS. The effect of the recycled ratio on the nitrogen removal is significant. Total nitrogen removal rate and nitrogen type of effluent would be determined by recycle ratio. The operation at low recycled ratio would result in worse total nitrogen removal, but the NH3-N of effluent would be lower. The operation in higher recycle ratio would be opposite to low recycle ratio. [ABSTRACT FROM AUTHOR]
- Published
- 2000
18. The effect of residual substrate utilization on sludge settling in an enhanced biological phosphorus removal process
- Author
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Chang, W. C., Chiou, R. J., and Ouyang, C. F.
- Subjects
- *
PHOSPHORUS , *ACTIVATED sludge process , *SEWAGE sludge , *WASTEWATER treatment - Published
- 1996
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19. Water adsorption of peanut kernels in a closed system with respect to moisture transfer
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Chiou, R. Y.-Y.
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FOOD industry - Published
- 1987
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20. Comparison of media and influence of petri plate position (inverted or upright) for determining fungal populations in bulk-stored, dry, seed-based foods
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Chiou, R. Y.-Y. and Beuchat, L. R.
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- *
FUNGI , *FOOD - Published
- 1985
21. D5 - Effect of food on the pharmacokinetics of extended release diltiazem
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Cerchio, K, Seibold, J, Porras, AG, Chiou, R, McNamara, M, Laskin, O, and Polvino, WJ
- Published
- 1995
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22. D4 - Pharmacokinetics of extended release diltiazem in elderly subjects
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Polvino, WJ, Portas, A, Laskin, O, Cerchio, K, Chiou, R., Han, R, Hoagland, V, and Lasseter, K
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- 1995
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23. The dimensionality of neural coding for cognitive control is gradually transformed within the lateral prefrontal cortex.
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Chiou R, Duncan J, Jefferies E, and Lambon Ralph MA
- Abstract
Implementing cognitive control relies on neural representations that are inherently high-dimensional and distributed across multiple subregions in the prefrontal cortex (PFC). Traditional approaches tackle prefrontal representation by reducing it into a unidimensional measure (univariate amplitude) or using them to distinguish a limited number of alternatives (pattern classification). By contrast, representational similarity analysis (RSA) enables flexibly formulating various hypotheses about informational contents underlying the neural codes, explicitly comparing hypotheses, and examining the representational alignment between brain regions. Here, we used a multifaceted paradigm wherein the difficulty of cognitive control was manipulated separately for five cognitive tasks. We used RSA to unveil representational contents, measure the representational alignment between regions, and quantify representational generality vs. specificity. We found a graded transition in the lateral PFC: The dorsocaudal PFC was tuned to task difficulty (indexed by reaction times), preferentially connected with the parietal cortex, and representationally generalisable across domains. The ventrorostral PFC was tuned to the abstract structure of tasks, preferentially connected with the temporal cortex, and representationally specific. The middle PFC (interposed between dorsocaudal and ventrorostral PFC) was tuned to individual task-sets, ranked in the middle in terms of connectivity and generalisability. Furthermore, whether a region was dimensionally rich or sparse co-varied with its functional profile: Low dimensionality (only gist) in the dorsocaudal PFC dovetailed with better generality, whereas high dimensionality (gist plus details) in the ventrorostral PFC corresponded with better ability to encode subtleties. Our findings, collectively, demonstrate how cognitive control is decomposed into distinct facets that transition steadily along prefrontal subregions. Significance statement Cognitive control is known to be a high-dimensional construct, implemented along the dorsocaudal-ventrorostral subregions of PFC. However, it remains unclear how prefrontal representations could be dissected in a multivariate fashion to reveal (1) what information is encoded in each subregion, (2) whether information systematically transforms across contiguous PFC subregions as a gradient, (3) how this transformation is affected by functional connectivity. Here we shed light on these issues by using RSA to decode informational composition in the PFC while using participant-specific localisers to facilitate individually-tailored precision. Our findings elucidate the functional organisation of PFC by revealing how a trade-off between dimensionality and generalisability unfolds in the PFC and highlight the strength of RSA in deciphering the coding of cognitive control., (Copyright © 2024 the authors.)
- Published
- 2024
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24. A function-based mapping of sensory integration along the cortical hierarchy.
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Wei W, Benn RA, Scholz R, Shevchenko V, Klatzmann U, Alberti F, Chiou R, Wassermann D, Vanderwal T, Smallwood J, and Margulies DS
- Subjects
- Humans, Male, Adult, Female, Cerebral Cortex physiology, Cerebral Cortex diagnostic imaging, Young Adult, Sensation physiology, Magnetic Resonance Imaging, Brain Mapping methods, Cognition physiology
- Abstract
Sensory information mainly travels along a hierarchy spanning unimodal to transmodal regions, forming multisensory integrative representations crucial for higher-order cognitive functions. Here, we develop an fMRI based two-dimensional framework to characterize sensory integration based on the anchoring role of the primary cortex in the organization of sensory processing. Sensory magnitude captures the percentage of variance explained by three primary sensory signals and decreases as the hierarchy ascends, exhibiting strong similarity to the known hierarchy and high stability across different conditions. Sensory angle converts associations with three primary sensory signals to an angle representing the proportional contributions of different sensory modalities. This dimension identifies differences between brain states and emphasizes how sensory integration changes flexibly in response to varying cognitive demands. Furthermore, meta-analytic functional decoding with our model highlights the close relationship between cognitive functions and sensory integration, showing its potential for future research of human cognition through sensory information processing., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)
- Published
- 2024
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25. Dissecting the neuroanatomy of creativity and curiosity: The subdivisions within networks matter.
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Chiou R, Branzi FM, Krieger-Redwood K, and Jefferies E
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- Humans, Creativity, Brain physiology, Brain diagnostic imaging, Exploratory Behavior physiology, Nerve Net physiology, Nerve Net diagnostic imaging
- Abstract
Ivancovsky et al. argue that the neurocognitive mechanisms of creativity and curiosity both rely on the interplay among brain networks. Research to date demonstrates that such inter-network dynamics are further complicated by functional fractionation within networks. Investigating how networks subdivide and reconfigure in service of a task offers insights about the precise anatomy that underpins creative and curious behaviour.
- Published
- 2024
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26. Semantic cognition versus numerical cognition: a topographical perspective.
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Chiou R, Margulies D, Soltanlou M, Jefferies E, and Kadosh RC
- Abstract
Semantic cognition and numerical cognition are dissociable faculties with separable neural mechanisms. However, recent advances in the cortical topography of the temporal and parietal lobes have revealed a common organisational principle for the neural representations of semantics and numbers. We discuss their convergence and divergence through the prism of topography., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2023
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27. A middle ground where executive control meets semantics: the neural substrates of semantic control are topographically sandwiched between the multiple-demand and default-mode systems.
- Author
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Chiou R, Jefferies E, Duncan J, Humphreys GF, and Lambon Ralph MA
- Subjects
- Humans, Magnetic Resonance Imaging, Cognition physiology, Language, Brain Mapping, Executive Function physiology, Semantics
- Abstract
Semantic control is the capability to operate on meaningful representations, selectively focusing on certain aspects of meaning while purposefully ignoring other aspects based on one's behavioral aim. This ability is especially vital for comprehending figurative/ambiguous language. It remains unclear why and how regions involved in semantic control seem reliably juxtaposed alongside other functionally specialized regions in the association cortex, prompting speculation about the relationship between topography and function. We investigated this issue by characterizing how semantic control regions topographically relate to the default-mode network (associated with memory and abstract cognition) and multiple-demand network (associated with executive control). Topographically, we established that semantic control areas were sandwiched by the default-mode and multi-demand networks, forming an orderly arrangement observed both at the individual and group level. Functionally, semantic control regions exhibited "hybrid" responses, fusing generic preferences for cognitively demanding operation (multiple-demand) and for meaningful representations (default-mode) into a domain-specific preference for difficult operation on meaningful representations. When projected onto the principal gradient of human connectome, the neural activity of semantic control showed a robustly dissociable trajectory from visuospatial control, implying different roles in the functional transition from sensation to cognition. We discuss why the hybrid functional profile of semantic control regions might result from their intermediate topographical positions on the cortex., (© The Author(s) 2022. Published by Oxford University Press.)
- Published
- 2023
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28. Bipartite functional fractionation within the neural system for social cognition supports the psychological continuity of self versus other.
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Chiou R, Cox CR, and Lambon Ralph MA
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- Humans, Brain Mapping methods, Social Cognition, Nerve Net, Neural Pathways, Magnetic Resonance Imaging methods, Cognition, Brain diagnostic imaging, Connectome
- Abstract
Research of social neuroscience establishes that regions in the brain's default-mode network (DN) and semantic network (SN) are engaged by socio-cognitive tasks. Research of the human connectome shows that DN and SN regions are both situated at the transmodal end of a cortical gradient but differ in their loci along this gradient. Here we integrated these 2 bodies of research, used the psychological continuity of self versus other as a "test-case," and used functional magnetic resonance imaging to investigate whether these 2 networks would encode social concepts differently. We found a robust dissociation between the DN and SN-while both networks contained sufficient information for decoding broad-stroke distinction of social categories, the DN carried more generalizable information for cross-classifying across social distance and emotive valence than did the SN. We also found that the overarching distinction of self versus other was a principal divider of the representational space while social distance was an auxiliary factor (subdivision, nested within the principal dimension), and this representational landscape was more manifested in the DN than in the SN. Taken together, our findings demonstrate how insights from connectome research can benefit social neuroscience and have implications for clarifying the 2 networks' differential contributions to social cognition., (© The Author(s) 2022. Published by Oxford University Press.)
- Published
- 2023
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29. Distinct and common neural coding of semantic and non-semantic control demands.
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Gao Z, Zheng L, Chiou R, Gouws A, Krieger-Redwood K, Wang X, Varga D, Ralph MAL, Smallwood J, and Jefferies E
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- Adult, Brain Mapping, Cerebral Cortex diagnostic imaging, Female, Humans, Magnetic Resonance Imaging, Male, Nerve Net diagnostic imaging, Pattern Recognition, Visual physiology, Reading, Semantics, Support Vector Machine, Verbal Learning physiology, Young Adult, Association, Cerebral Cortex physiology, Executive Function physiology, Memory, Short-Term physiology, Nerve Net physiology
- Abstract
The flexible retrieval of knowledge is critical in everyday situations involving problem solving, reasoning and social interaction. Current theories emphasise the importance of a left-lateralised semantic control network (SCN) in supporting flexible semantic behaviour, while a bilateral multiple-demand network (MDN) is implicated in executive functions across domains. No study, however, has examined whether semantic and non-semantic demands are reflected in a common neural code within regions specifically implicated in semantic control. Using functional MRI and univariate parametric modulation analysis as well as multivariate pattern analysis, we found that semantic and non-semantic demands gave rise to both similar and distinct neural responses across control-related networks. Though activity patterns in SCN and MDN could decode the difficulty of both semantic and verbal working memory decisions, there was no shared common neural coding of cognitive demands in SCN regions. In contrast, regions in MDN showed common patterns across manipulations of semantic and working memory control demands, with successful cross-classification of difficulty across tasks. Therefore, SCN and MDN can be dissociated according to the information they maintain about cognitive demands., Competing Interests: Declaration of Competing Interest The authors declare no competing financial interests., (Copyright © 2021. Published by Elsevier Inc.)
- Published
- 2021
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30. We Need Deeper Understanding About the Neurocognitive Mechanisms of Moral Righteousness in an Era of Online Vigilantism and Cancel Culture.
- Author
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Chiou R
- Subjects
- Morals, Violence
- Published
- 2020
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31. Bipartite Functional Fractionation within the Default Network Supports Disparate Forms of Internally Oriented Cognition.
- Author
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Chiou R, Humphreys GF, and Lambon Ralph MA
- Subjects
- Adult, Brain Mapping, Female, Humans, Magnetic Resonance Imaging, Male, Memory physiology, Psychophysics, Semantics, Young Adult, Brain physiology, Cognition physiology, Default Mode Network physiology
- Abstract
Our understanding about the functionality of the brain's default network (DN) has significantly evolved over the past decade. Whereas traditional views define this network based on its suspension/disengagement during task-oriented behavior, contemporary accounts have characterized various situations wherein the DN actively contributes to task performance. However, it is unclear how different task-contexts drive componential regions of the DN to coalesce into a unitary network and fractionate into different subnetworks. Here we report a compendium of evidence that provides answers to these questions. Across multiple analyses, we found a striking dyadic structure within the DN in terms of the profiles of task-triggered fMRI response and effective connectivity, significantly extending beyond previous inferences based on meta-analysis and resting-state activities. In this dichotomy, one subset of DN regions prefers mental activities "interfacing with" perceptible events, while the other subset prefers activities "detached from" perceptible events. While both show a common "aversion" to sensory-motoric activities, their differential preferences manifest a subdivision that sheds light upon the taxonomy of the brain's memory systems. This dichotomy is consistent with proposals of a macroscale gradational structure spanning across the cerebrum. This gradient increases its representational complexity, from primitive sensory-motoric processing, through lexical-semantic representations, to elaborated self-generated thoughts., (© The Author(s) 2020. Published by Oxford University Press.)
- Published
- 2020
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32. Unveiling the dynamic interplay between the hub- and spoke-components of the brain's semantic system and its impact on human behaviour.
- Author
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Chiou R and Lambon Ralph MA
- Subjects
- Adult, Cerebral Cortex diagnostic imaging, Connectome, Female, Humans, Magnetic Resonance Imaging, Male, Nerve Net diagnostic imaging, Semantics, Temporal Lobe diagnostic imaging, Young Adult, Brain Mapping, Cerebral Cortex physiology, Nerve Net physiology, Pattern Recognition, Visual physiology, Recognition, Psychology physiology, Temporal Lobe physiology
- Abstract
The neural architecture of semantic knowledge comprises two key structures: (i) A set of widely dispersed regions, located adjacent to the sensorimotor cortices, serve as spokes that represent various modality-specific and context-dependent contents. (ii) The anterior-temporal lobe (ATL) serves as a hub that computes the nonlinear mappings required to transform modality-specific information into pan-modality, multifaceted concepts. Little is understood regarding whether neural dynamics between the hub and spokes might flexibly alter depending on the nature of a concept and how it impinges upon behaviour. Using fMRI, we demonstrate for the first time that the ATL serves as a 'pivot' which dynamically forms flexible long-range networks with cortical modules specialised for different domains (in the present case, the knowledge about actions and places). In two experiments, we manipulated semantic congruity and asked participants to recognise visually presented items. In Experiment 1 (dual-object displays), the ATL increased its functional coupling with the bilateral frontoparietal action-sensitive system when the objects formed a pair that permitted semantically meaningful action. In Experiment 2 (objects embedded in a scene), the ATL augmented its coupling with the retrosplenial cortex of the place-sensitive system when the objects and scene formed a semantically coherent ensemble. Causative connectivity revealed that, while communication between the hub and spokes was bidirectional, the hub's directional impact on spokes dwarfed the strength of the inverse spoke-to-hub connectivity. Furthermore, the size of behavioural congruity effects co-varied with the strength of neural coupling between the ATL hub and action- / place-related spokes, evident both at the within-individual level (the behavioural fluctuation across scanning runs) and between-individual level (the behavioural variation of between participants). Together, these findings have important implications for understanding the machinery that links neural dynamics with semantic cognition., (Copyright © 2019 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2019
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33. Exploring the functional nature of synaesthetic colour: Dissociations from colour perception and imagery.
- Author
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Chiou R, Rich AN, Rogers S, and Pearson J
- Subjects
- Adult, Color, Female, Humans, Male, Photic Stimulation, Psychophysics, Synesthesia, Color Perception, Imagination, Perceptual Disorders, Vision, Binocular
- Abstract
Individuals with grapheme-colour synaesthesia experience anomalous colours when reading achromatic text. These unusual experiences have been said to resemble 'normal' colour perception or colour imagery, but studying the nature of synaesthesia remains difficult. In the present study, we report novel evidence that synaesthetic colour impacts conscious vision in a way that is different from both colour perception and imagery. Presenting 'normal' colour prior to binocular rivalry induces a location-dependent suppressive bias reflecting local habituation. By contrast, a grapheme that evokes synaesthetic colour induces a facilitatory bias reflecting priming that is not constrained to the inducing grapheme's location. This priming does not occur in non-synaesthetes and does not result from response bias. It is sensitive to diversion of visual attention away from the grapheme, but resistant to sensory perturbation, reflecting a reliance on cognitive rather than sensory mechanisms. Whereas colour imagery in non-synaesthetes causes local priming that relies on the locus of imagined colour, imagery in synaesthetes caused global priming not dependent on the locus of imagery. These data suggest a unique psychophysical profile of high-level colour processing in synaesthetes. Our novel findings and method will be critical to testing theories of synaesthesia and visual awareness., (Copyright © 2018 Elsevier B.V. All rights reserved.)
- Published
- 2018
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34. Controlled semantic cognition relies upon dynamic and flexible interactions between the executive 'semantic control' and hub-and-spoke 'semantic representation' systems.
- Author
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Chiou R, Humphreys GF, Jung J, and Lambon Ralph MA
- Subjects
- Adult, Brain Mapping, Cerebral Cortex diagnostic imaging, Female, Humans, Magnetic Resonance Imaging, Male, Nerve Net diagnostic imaging, Nerve Net physiology, Neuroimaging, Young Adult, Cerebral Cortex physiology, Cognition physiology, Concept Formation physiology, Executive Function physiology
- Abstract
Built upon a wealth of neuroimaging, neurostimulation, and neuropsychology data, a recent proposal set forth a framework termed controlled semantic cognition (CSC) to account for how the brain underpins the ability to flexibly use semantic knowledge (Lambon Ralph et al., 2017; Nature Reviews Neuroscience). In CSC, the 'semantic control' system, underpinned predominantly by the prefrontal cortex, dynamically monitors and modulates the 'semantic representation' system that consists of a 'hub' (anterior temporal lobe, ATL) and multiple 'spokes' (modality-specific areas). CSC predicts that unfamiliar and exacting semantic tasks should intensify communication between the 'control' and 'representation' systems, relative to familiar and less taxing tasks. In the present study, we used functional magnetic resonance imaging (fMRI) to test this hypothesis. Participants paired unrelated concepts by canonical colours (a less accustomed task - e.g., pairing ketchup with fire-extinguishers due to both being red) or paired well-related concepts by semantic relationship (a typical task - e.g., ketchup is related to mustard). We found the 'control' system was more engaged by atypical than typical pairing. While both tasks activated the ATL 'hub', colour pairing additionally involved occipitotemporal 'spoke' regions abutting areas of hue perception. Furthermore, we uncovered a gradient along the ventral temporal cortex, transitioning from the caudal 'spoke' zones preferring canonical colour processing to the rostral 'hub' zones preferring semantic relationship. Functional connectivity also differed between the tasks: Compared with semantic pairing, colour pairing relied more upon the inferior frontal gyrus, a key node of the control system, driving enhanced connectivity with occipitotemporal 'spoke'. Together, our findings characterise the interaction within the neural architecture of semantic cognition - the control system dynamically heightens its connectivity with relevant components of the representation system, in response to different semantic contents and difficulty levels., (Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2018
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35. The anterior-ventrolateral temporal lobe contributes to boosting visual working memory capacity for items carrying semantic information.
- Author
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Chiou R and Lambon Ralph MA
- Subjects
- Adult, Female, Humans, Male, Young Adult, Facial Recognition physiology, Memory, Short-Term physiology, Recognition, Psychology physiology, Semantics, Temporal Lobe physiology, Transcranial Magnetic Stimulation methods
- Abstract
Working memory (WM) is a buffer that temporarily maintains information, be it visual or auditory, in an active state, caching its contents for online rehearsal or manipulation. How the brain enables long-term semantic knowledge to affect the WM buffer is a theoretically significant issue awaiting further investigation. In the present study, we capitalise on the knowledge about famous individuals as a 'test-case' to study how it impinges upon WM capacity for human faces and its neural substrate. Using continuous theta-burst transcranial stimulation combined with a psychophysical task probing WM storage for varying contents, we provide compelling evidence that (1) faces (regardless of familiarity) continued to accrue in the WM buffer with longer encoding time, whereas for meaningless stimuli (colour shades) there was little increment; (2) the rate of WM accrual was significantly more efficient for famous faces, compared to unknown faces; (3) the right anterior-ventrolateral temporal lobe (ATL) causally mediated this superior WM storage for famous faces. Specifically, disrupting the ATL (a region tuned to semantic knowledge including person identity) selectively hinders WM accrual for celebrity faces while leaving the accrual for unfamiliar faces intact. Further, this 'semantically-accelerated' storage is impervious to disruption of the right middle frontal gyrus and vertex, supporting the specific and causative contribution of the right ATL. Our finding advances the understanding of the neural architecture of WM, demonstrating that it depends on interaction with long-term semantic knowledge underpinned by the ATL, which causally expands the WM buffer when visual content carries semantic information., (Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2018
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36. Sensory dynamics of visual hallucinations in the normal population.
- Author
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Pearson J, Chiou R, Rogers S, Wicken M, Heitmann S, and Ermentrout B
- Subjects
- Humans, Models, Neurological, Hallucinations, Visual Cortex physiology
- Abstract
Hallucinations occur in both normal and clinical populations. Due to their unpredictability and complexity, the mechanisms underlying hallucinations remain largely untested. Here we show that visual hallucinations can be induced in the normal population by visual flicker, limited to an annulus that constricts content complexity to simple moving grey blobs, allowing objective mechanistic investigation. Hallucination strength peaked at ~11 Hz flicker and was dependent on cortical processing. Hallucinated motion speed increased with flicker rate, when mapped onto visual cortex it was independent of eccentricity, underwent local sensory adaptation and showed the same bistable and mnemonic dynamics as sensory perception. A neural field model with motion selectivity provides a mechanism for both hallucinations and perception. Our results demonstrate that hallucinations can be studied objectively, and they share multiple mechanisms with sensory perception. We anticipate that this assay will be critical to test theories of human consciousness and clinical models of hallucination., Competing Interests: The authors declare that no competing interests exist.
- Published
- 2016
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37. The anterior temporal cortex is a primary semantic source of top-down influences on object recognition.
- Author
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Chiou R and Lambon Ralph MA
- Subjects
- Adult, Female, Humans, Magnetic Resonance Imaging, Male, Photic Stimulation, Temporal Lobe diagnostic imaging, Transcranial Magnetic Stimulation, Young Adult, Form Perception physiology, Pattern Recognition, Visual physiology, Recognition, Psychology physiology, Temporal Lobe physiology
- Abstract
Perception emerges from a dynamic interplay between feed-forward sensory input and feedback modulation along the cascade of neural processing. Prior knowledge, a major form of top-down modulatory signal, benefits perception by enabling efficacious inference and resolving ambiguity, particularly under circumstances of degraded visual input. Despite semantic information being a potentially critical source of this top-down influence, to date, the core neural substrate of semantic knowledge (the anterolateral temporal lobe - ATL) has not been considered as a key component of the feedback system. Here we provide direct evidence of its significance for visual cognition - the ATL underpins the semantic aspect of object recognition, amalgamating sensory-based (amount of accumulated sensory input) and semantic-based (representational proximity between exemplars and typicality of appearance) influences. Using transcranial theta-burst stimulation combined with a novel visual identification paradigm, we demonstrate that the left ATL contributes to discrimination between visual objects. Crucially, its contribution is especially vital under situations where semantic knowledge is most needed for supplementing deficiency of input (brief visual exposure), discerning analogously-coded exemplars (close representational distance), and resolving discordance (target appearance violating the statistical typicality of its category). Our findings characterise functional properties of the ATL in object recognition: this neural structure is summoned to augment the visual system when the latter is overtaxed by challenging conditions (insufficient input, overlapped neural coding, and conflict between incoming signal and expected configuration). This suggests a need to revisit current theories of object recognition, incorporating the ATL that interfaces high-level vision with semantic knowledge., (Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.)
- Published
- 2016
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38. Task-Related Dynamic Division of Labor Between Anterior Temporal and Lateral Occipital Cortices in Representing Object Size.
- Author
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Chiou R and Lambon Ralph MA
- Subjects
- Adult, Brain Mapping, Female, Humans, Magnetic Resonance Imaging, Male, Photic Stimulation, Theta Rhythm physiology, Transcranial Magnetic Stimulation methods, Visual Cortex physiology, Occipital Lobe physiology, Pattern Recognition, Visual physiology, Temporal Lobe physiology, Visual Pathways physiology
- Abstract
Unlabelled: Object size is represented by functionally distinct sectors along the ventral visual pathway. The early visual cortex encodes objects' sensory-retinal size. Subsequently, the occipitotemporal cortex computes objects' canonical size based on statistical regularities of visual features. Although the neurocomputation of size has been studied in a "bottom-up" sensory-driven framework, little is known about how perceptual size information is transformed into conceptual knowledge and how this computation is modulated by "top-down" goal-driven signals. Using continuous theta burst stimulation, we demonstrated that behavioral goal shapes the neurocognitive network underpinning object size. We manipulated the congruency of perceptual versus conceptual object size, which provides a robust behavioral probe reflecting implicit size knowledge. Neurostimulation was targeted at the lateral occipital cortex (LOC), a key region for object perception, or the anterior temporal lobe (ATL), a "hub" of supramodal conceptual processing. We observed striking contextual modulation of the neurocognitive architecture: when human participants judged perceptual size, the congruency effect was significantly attenuated by LOC stimulation but stayed resilient to ATL stimulation. By contrast, when they judged conceptual size, both LOC and ATL stimulation eradicated the otherwise robust effect. Our findings demonstrate disparate functional profiles of the LOC and ATL, providing the first evidence of a malleable network adaptively altering its division of labor with top-down states. The LOC, regardless of task demand, automatically represents "bottom-up" statistical regularities of visual conformation (reflecting typical object size), whereas the ATL contributes to this computation when the context requires semantically based linkage of visual attributes to object recognition., Significance Statement: In the present study, we provide compelling evidence that the "top-down" cognitive state of an observer changes the dynamic interaction between different subregions of the ventral temporal cortex. Using inhibitory neurostimulation combined with a novel paradigm, we demonstrate a flexible division of labor in the neurocognitive architecture that underpins size knowledge: the lateral occipital cortex codes perceptually based aspects (statistical visual configuration of small/large objects), whereas the anterior temporal lobe represents semantically based aspects (object identity), with their involvement interactively weighted by task demand. The interactive nature of the ventral temporal cortex highlights how top-down modulation constrains and shapes neural representations in the visual system., (Copyright © 2016 Chiou and Lambon Ralph.)
- Published
- 2016
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39. Volitional Mechanisms Mediate the Cuing Effect of Pitch on Attention Orienting: The Influences of Perceptual Difficulty and Response Pressure.
- Author
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Chiou R and Rich AN
- Subjects
- Adult, Female, Humans, Male, Orientation, Spatial physiology, Young Adult, Attention physiology, Cues, Pitch Perception physiology, Space Perception physiology, Volition physiology
- Abstract
Our cognitive system tends to link auditory pitch with spatial location in a specific manner (ie high-pitched sounds are usually associated with an upper location, and low sounds are associated with a lower location). Recent studies have demonstrated that this cross-modality association biases the allocation of visual attention and affects performance despite the auditory stimuli being irrelevant to the behavioural task. There is, however, a discrepancy between studies in their interpretation of the underlying mechanisms. Whereas we have previously claimed that the pitch-location mapping is mediated by volitional shifts of attention (Chiou & Rich, 2012, Perception, 41: , 339-353), other researchers suggest that this cross-modal effect reflects automatic shifts of attention (Mossbridge, Grabowecky, & Suzuki, 2011, Cognition, 121: , 133-139). Here we report a series of three experiments examining the effects of perceptual and response-related pressure on the ability of nonpredictive pitch to bias visual attention. We compare it with two control cues: a predictive pitch that triggers voluntary attention shifts and a salient peripheral flash that evokes involuntary shifts. The results show that the effect of nonpredictive pitch is abolished by pressure at either perceptual or response levels. By contrast, the effects of the two control cues remain significant, demonstrating the robustness of informative and perceptually salient stimuli in directing attention. This distinction suggests that, in contexts of high perceptual demand and response pressure, cognitive resources are primarily engaged by the task-relevant stimuli, which effectively prevents uninformative pitch from orienting attention to its cross-modally associated location. These findings are consistent with the hypothesis that the link between pitch and location affects attentional deployment via volitional rather than automatic mechanisms., (© 2015 SAGE Publications.)
- Published
- 2015
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40. Mechanical study of polycaprolactone-hydroxyapatite porous scaffolds created by porogen-based solid freeform fabrication method.
- Author
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Lu L, Zhang Q, Wootton DM, Chiou R, Li D, Lu B, Lelkes PI, and Zhou J
- Subjects
- Compressive Strength, Elastic Modulus, Equipment Design, Equipment Failure Analysis, Hardness, Materials Testing, Porosity, Tensile Strength, Bone Substitutes chemical synthesis, Durapatite chemistry, Molecular Imprinting methods, Polyesters chemistry, Tissue Scaffolds
- Abstract
Materials and Methods: Polycaprolactone (PCL) and polycaprolactone-hydroxyapatite (PCL-HA) scaffolds with 600-µm pore size were fabricated by drop-on-demand printing (DDP) structured porogen method followed with injection molding. Specimens with special dimensions of 4.2×4.2×5.4 mm3 and 6.6×6.6×13.8 mm3 were designed and fabricated for compression and tensile tests, respectively. The mechanical study was performed on both solid and porous PCL and PCL-HA samples. The effect on mechanical properties of the HA content ratio in PCL-HA composites was investigated., Results: Porous scaffold made of 80/20 PCL-HA composite had an ultimate compressive strength of 3.7±0.2 MPa and compression modulus of 61.4±3.4 MPa, which is in the range of reported trabecular bone's compressive strength. Increasing the concentration of HA in the composites raised compressive properties and stiffness significantly (P<0.05), which demonstrates that PCL-HA composites have the potential for application in bone regeneration. Tensile test of solid PCL and PCL-HA composites showed that the ultimate tensile strength and tensile modulus increased with increases of the concentration of HA in the composites. The tensile test was also conducted on PCL porous scaffold; the result indicated that the scaffold was slightly softer and weaker in tension compared with compression., Conclusions: Combining compression and tensile test results, our study may guide the possible application of these biomaterials in bone tissue engineering and support further development of microstructure-based models of scaffold mechanical properties.
- Published
- 2014
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41. Dynamic changes in intracellular ROS levels regulate airway basal stem cell homeostasis through Nrf2-dependent Notch signaling.
- Author
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Paul MK, Bisht B, Darmawan DO, Chiou R, Ha VL, Wallace WD, Chon AT, Hegab AE, Grogan T, Elashoff DA, Alva-Ornelas JA, and Gomperts BN
- Subjects
- Animals, Antioxidants metabolism, Cell Cycle, Cell Differentiation, Cell Proliferation, Homeostasis, Humans, Mice, Oxidation-Reduction, Polidocanol, Polyethylene Glycols chemistry, Signal Transduction, Wound Healing, NF-E2-Related Factor 2 metabolism, Reactive Oxygen Species metabolism, Receptors, Notch metabolism, Stem Cells cytology, Trachea cytology
- Abstract
Airways are exposed to myriad environmental and damaging agents such as reactive oxygen species (ROS), which also have physiological roles as signaling molecules that regulate stem cell function. However, the functional significance of both steady and dynamically changing ROS levels in different stem cell populations, as well as downstream mechanisms that integrate ROS sensing into decisions regarding stem cell homeostasis, are unclear. Here, we show in mouse and human airway basal stem cells (ABSCs) that intracellular flux from low to moderate ROS levels is required for stem cell self-renewal and proliferation. Changing ROS levels activate Nrf2, which activates the Notch pathway to stimulate ABSC self-renewal and an antioxidant program that scavenges intracellular ROS, returning overall ROS levels to a low state to maintain homeostatic balance. This redox-mediated regulation of lung stem cell function has significant implications for stem cell biology, repair of lung injuries, and diseases such as cancer., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2014
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42. A conceptual lemon: theta burst stimulation to the left anterior temporal lobe untangles object representation and its canonical color.
- Author
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Chiou R, Sowman PF, Etchell AC, and Rich AN
- Subjects
- Adult, Color, Female, Humans, Male, Young Adult, Color Perception physiology, Photic Stimulation methods, Temporal Lobe physiology, Theta Rhythm physiology, Transcranial Magnetic Stimulation methods
- Abstract
Object recognition benefits greatly from our knowledge of typical color (e.g., a lemon is usually yellow). Most research on object color knowledge focuses on whether both knowledge and perception of object color recruit the well-established neural substrates of color vision (the V4 complex). Compared with the intensive investigation of the V4 complex, we know little about where and how neural mechanisms beyond V4 contribute to color knowledge. The anterior temporal lobe (ATL) is thought to act as a "hub" that supports semantic memory by integrating different modality-specific contents into a meaningful entity at a supramodal conceptual level, making it a good candidate zone for mediating the mappings between object attributes. Here, we explore whether the ATL is critical for integrating typical color with other object attributes (object shape and name), akin to its role in combining nonperceptual semantic representations. In separate experimental sessions, we applied TMS to disrupt neural processing in the left ATL and a control site (the occipital pole). Participants performed an object naming task that probes color knowledge and elicits a reliable color congruency effect as well as a control quantity naming task that also elicits a cognitive congruency effect but involves no conceptual integration. Critically, ATL stimulation eliminated the otherwise robust color congruency effect but had no impact on the numerical congruency effect, indicating a selective disruption of object color knowledge. Neither color nor numerical congruency effects were affected by stimulation at the control occipital site, ruling out nonspecific effects of cortical stimulation. Our findings suggest that the ATL is involved in the representation of object concepts that include their canonical colors.
- Published
- 2014
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43. The role of conceptual knowledge in understanding synaesthesia: Evaluating contemporary findings from a "hub-and-spokes" perspective.
- Author
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Chiou R and Rich AN
- Abstract
Synesthesia is a phenomenon in which stimulation in one sensory modality triggers involuntary experiences typically not associated with that stimulation. Inducing stimuli (inducers) and synesthetic experiences (concurrents) may occur within the same modality (e.g., seeing colors while reading achromatic text) or span across different modalities (e.g., tasting flavors while listening to music). Although there has been considerable progress over the last decade in understanding the cognitive and neural mechanisms of synesthesia, the focus of current neurocognitive models of synesthesia does not encompass many crucial psychophysical characteristics documented in behavioral research. Prominent theories of the neurophysiological basis of synesthesia construe it as a perceptual phenomenon and hence focus primarily on the modality-specific brain regions for perception. Many behavioral studies, however, suggest an essential role for conceptual-level information in synesthesia. For example, there is evidence that synesthetic experience arises subsequent to identification of an inducing stimulus, differs substantially from real perceptual events, can be akin to perceptual memory, and is susceptible to lexical/semantic contexts. These data suggest that neural mechanisms lying beyond the realm of the perceptual cortex (especially the visual system), such as regions subserving conceptual knowledge, may play pivotal roles in the neural architecture of synesthesia. Here we discuss the significance of non-perceptual mechanisms that call for a re-evaluation of the emphasis on synesthesia as a perceptual phenomenon. We also review recent studies which hint that some aspects of synesthesia resemble our general conceptual knowledge for object attributes, at both psychophysical and neural levels. We then present a conceptual-mediation model of synesthesia in which the inducer and concurrent are linked within a conceptual-level representation. This "inducer-to-concurrent" nexus is maintained within a supramodal "hub," while the subjective (bodily) experience of its resultant concurrent (e.g., a color) may then require activation of "spokes" in the perception-related cortices. This hypothesized "hub-and-spoke" structure would engage a distributed network of cortical regions and may account for the full breadth of this intriguing phenomenon.
- Published
- 2014
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44. Beyond colour perception: auditory-visual synaesthesia induces experiences of geometric objects in specific locations.
- Author
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Chiou R, Stelter M, and Rich AN
- Subjects
- Acoustic Stimulation, Female, Fixation, Ocular, Form Perception physiology, Humans, Male, Middle Aged, Music psychology, Photic Stimulation, Psychomotor Performance physiology, Reaction Time physiology, Reproducibility of Results, Synesthesia, Young Adult, Auditory Perception physiology, Color Perception physiology, Perceptual Disorders psychology, Visual Perception physiology
- Abstract
Our brain constantly integrates signals across different senses. Auditory-visual synaesthesia is an unusual form of cross-modal integration in which sounds evoke involuntary visual experiences. Previous research primarily focuses on synaesthetic colour, but little is known about non-colour synaesthetic visual features. Here we studied a group of synaesthetes for whom sounds elicit consistent visual experiences of coloured 'geometric objects' located at specific spatial location. Changes in auditory pitch alter the brightness, size, and spatial height of synaesthetic experiences in a systematic manner resembling the cross-modal correspondences of non-synaesthetes, implying synaesthesia may recruit cognitive/neural mechanisms for 'normal' cross-modal processes. To objectively assess the impact of synaesthetic objects on behaviour, we devised a multi-feature cross-modal synaesthetic congruency paradigm and asked participants to perform speeded colour or shape discrimination. We found irrelevant sounds influenced performance, as quantified by congruency effects, demonstrating that synaesthetes were not able to suppress their synaesthetic experiences even when these were irrelevant for the task. Furthermore, we found some evidence for task-specific effects consistent with feature-based attention acting on the constituent features of synaesthetic objects: synaesthetic colours appeared to have a stronger impact on performance than synaesthetic shapes when synaesthetes attended to colour, and vice versa when they attended to shape. We provide the first objective evidence that visual synaesthetic experience can involve multiple features forming object-like percepts and suggest that each feature can be selected by attention despite it being internally generated. These findings suggest theories of the brain mechanisms of synaesthesia need to incorporate a broader neural network underpinning multiple visual features, perceptual knowledge, and feature integration, rather than solely focussing on colour-sensitive areas., (Copyright © 2012 Elsevier Ltd. All rights reserved.)
- Published
- 2013
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45. Biocompatibility and biodegradation studies of PCL/β-TCP bone tissue scaffold fabricated by structural porogen method.
- Author
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Lu L, Zhang Q, Wootton D, Chiou R, Li D, Lu B, Lelkes P, and Zhou J
- Subjects
- Animals, Biocompatible Materials chemical synthesis, Biocompatible Materials chemistry, Bone Substitutes chemistry, Bone and Bones drug effects, Bone and Bones physiology, Calcium Phosphates chemical synthesis, Cells, Cultured, Computer Simulation, Feasibility Studies, Humans, Materials Testing, Mice, Osseointegration drug effects, Osseointegration physiology, Polyesters chemical synthesis, Porosity, Tissue Engineering instrumentation, Absorbable Implants, Bone Substitutes chemical synthesis, Calcium Phosphates chemistry, Polyesters chemistry, Tissue Engineering methods, Tissue Scaffolds chemistry
- Abstract
Three-dimensional printer (3DP) (Z-Corp) is a solid freeform fabrication system capable of generating sub-millimeter physical features required for tissue engineering scaffolds. By using plaster composite materials, 3DP can fabricate a universal porogen which can be injected with a wide range of high melting temperature biomaterials. Here we report results toward the manufacture of either pure polycaprolactone (PCL) or homogeneous composites of 90/10 or 80/20 (w/w) PCL/beta-tricalcium phosphate (β-TCP) by injection molding into plaster composite porogens fabricated by 3DP. The resolution of printed plaster porogens and produced scaffolds was studied by scanning electron microscopy. Cytotoxicity test on scaffold extracts and biocompatibility test on the scaffolds as a matrix supporting murine osteoblast (7F2) and endothelial hybridoma (EAhy 926) cells growth for up to 4 days showed that the porogens removal process had only negligible effects on cell proliferation. The biodegradation tests of pure PCL and PCL/β-TCP composites were performed in DMEM with 10 % (v/v) FBS for up to 6 weeks. The PCL/β-TCP composites show faster degradation rate than that of pure PCL due to the addition of β-TCP, and the strength of 80/20 PCL/β-TCP composite is still suitable for human cancellous bone healing support after 6 weeks degradation. Combining precisely controlled porogen fabrication structure, good biocompatibility, and suitable mechanical properties after biodegradation, PCL/β-TCP scaffolds fabricated by 3DP porogen method provide essential capability for bone tissue engineering.
- Published
- 2012
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46. Cross-modality correspondence between pitch and spatial location modulates attentional orienting.
- Author
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Chiou R and Rich AN
- Subjects
- Adult, Analysis of Variance, Cues, Female, Humans, Male, Reaction Time physiology, Students psychology, Young Adult, Attention physiology, Orientation physiology, Pitch Perception physiology, Space Perception physiology
- Abstract
The brain constantly integrates incoming signals across the senses to form a cohesive view of the world. Most studies on multisensory integration concern the roles of spatial and temporal parameters. However, recent findings suggest cross-modal correspondences (eg high-pitched sounds associated with bright, small objects located high up) also affect multisensory integration. Here, we focus on the association between auditory pitch and spatial location. Surprisingly little is known about the cognitive and perceptual roots of this phenomenon, despite its long use in ergonomic design. In a series of experiments, we explore how this cross-modal mapping affects the allocation of attention with an attentional cuing paradigm. Our results demonstrate that high and low tones induce attention shifts to upper or lower locations, depending on pitch height. Furthermore, this pitch-induced cuing effect is susceptible to contextual manipulations and volitional control. These findings suggest the cross-modal interaction between pitch and location originates from an attentional level rather than from response mapping alone. The flexible contextual mapping between pitch and location, as well as its susceptibility to top-down control, suggests the pitch-induced cuing effect is primarily mediated by cognitive processes after initial sensory encoding and occurs at a relatively late stage of voluntary attention orienting.
- Published
- 2012
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47. Novel modeling concept for evaluating the effects of cadmium and copper on heterotrophic growth and lysis rates in activated sludge process.
- Author
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Pai TY, Wang SC, Lo HM, Chiang CF, Liu MH, Chiou RJ, Chen WY, Hung PS, Liao WC, and Leu HG
- Subjects
- Bacteria growth & development, Kinetics, Bacteria drug effects, Biodegradation, Environmental, Cadmium pharmacology, Copper pharmacology, Models, Theoretical, Sewage microbiology
- Abstract
A new modeling concept to evaluate the effects of cadmium and copper on heterotrophic growth rate constant (mu(H)) and lysis rate constant (b(H)) in activated sludge was introduced. The oxygen uptake rate (OUR) was employed to measure the constants. The results indicated that the mu(H) value decreased from 4.52 to 3.26 d(-1) or by 28% when 0.7 mg L(-1) of cadmium was added. Contrarily the b(H) value increased from 0.31 to 0.35 d(-1) or by 11%. When adding 0.7 mg L(-1) of copper, the mu(H) value decreased to 2.80 d(-1) or by 38%. The b(H) value increased to 0.42 d(-1) or by 35%. After regression, the inhibitory effect was in a good agreement with non-competitive inhibition kinetic. The inhibition coefficient values for cadmium and copper were 1.82 and 1.21 mg L(-1), respectively. The relation between the b(H) values and heavy metal concentrations agreed with exponential type well. The heavy metal would enhance b(H) value. Using these data, a new kinetic model was established and used to simulate the degree of inhibition. It was evident that not only the inhibitory effect on mu(H) but also that the enhancement effect on b(H) should be considered when heavy metal presented.
- Published
- 2009
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48. Assessment of the CYP3A-mediated drug interaction potential of anacetrapib, a potent cholesteryl ester transfer protein (CETP) inhibitor, in healthy volunteers.
- Author
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Krishna R, Bergman AJ, Jin B, Garg A, Roadcap B, Chiou R, Dru J, Cote J, Laethem T, Wang RW, Didolkar V, Vets E, Gottesdiener K, and Wagner JA
- Subjects
- Adolescent, Adult, Cytochrome P-450 CYP3A, Cytochrome P-450 Enzyme Inhibitors, Drug Interactions, Hepatocytes drug effects, Hepatocytes metabolism, Humans, In Vitro Techniques, Ketoconazole pharmacology, Microsomes, Liver drug effects, Microsomes, Liver metabolism, Midazolam pharmacology, Middle Aged, Oxazolidinones adverse effects, Young Adult, Cholesterol Ester Transfer Proteins antagonists & inhibitors, Cytochrome P-450 Enzyme System physiology, Oxazolidinones pharmacology
- Abstract
In this study, midazolam was used as a probe-sensitive CYP3A substrate to investigate the effect of anacetrapib on CYP3A activity, and ketoconazole was used as a probe-inhibitor to investigate the effect of potent CYP3A inhibition on the pharmacokinetics of anacetrapib, a novel cholesteryl ester transfer protein inhibitor in development for the treatment of dyslipidemia. Two partially blinded, randomized, 2-period, fixed-sequence studies were performed. Safety, tolerability, and midazolam and anacetrapib plasma concentrations were assessed. All treatments were generally well tolerated. The geometric mean ratios (90% confidence interval) of midazolam with anacetrapib/midazolam alone for AUC0-infinity and Cmax were 1.04 (0.94, 1.14) and 1.15 (0.97, 1.37), respectively. Exposure to anacetrapib was increased by ketoconazole--specifically, the geometric mean ratios (90% confidence interval) of anacetrapib with ketoconazole/anacetrapib alone for AUC0-infinity and Cmax were 4.58 (3.68, 5.71) and 2.37 (2.02, 2.78), respectively. The study showed that anacetrapib does not inhibit or induce CYP3A activity. Furthermore, anacetrapib appears to be a moderately sensitive substrate of CYP3A.
- Published
- 2009
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49. Evaluating impact level of different factors in environmental impact assessment for incinerator plants using GM (1, N) model.
- Author
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Pai TY, Chiou RJ, and Wen HH
- Subjects
- Risk Assessment, Taiwan, Environment, Environmental Monitoring methods, Incineration, Models, Theoretical
- Abstract
In this study, the impact levels in environmental impact assessment (EIA) reports of 10 incinerator plants were quantified and discussed. The relationship between the quantified impact levels and the plant scale factors of BeiTou, LiZe, BaLi, LuTsao, RenWu, PingTung, SiJhou and HsinChu were constructed, and the impact levels of the GangShan (GS) and YongKong (YK) plants were predicted using grey model GM (1, N). Finally, the effects of plant scale factors on impact levels were evaluated using grey model GM (1, N) too. According to the predicted results of GM, the relative errors of topography/geology/soil, air quality, hydrology/water quality, solid waste, noise, terrestrial fauna/flora, aquatic fauna/flora and traffic in the GS plant were 17%, 14%, 15%, 17%, 75%, 16%, 13%, and 37%, respectively. The relative errors of the same environmental items in the YK plant were 1%, 18%, 10%, 40%, 37%, 3%, 25% and 33%, respectively. According to GM (1, N), design capacity (DC) and heat value (HV) were the plant scale factors that affected the impact levels significantly in each environmental item, and thus were the most significant plant scale factors. GM (1, N) was effective in predicting the environmental impact and analyzing the reasonableness of the impact. If there is an EIA for a new incinerator plant to be reviewed in the future, the official committee of the Taiwan EPA could review the reasonableness of impact levels in EIA reports quickly.
- Published
- 2008
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50. Ethanol-mediated variations in cellular fatty acid composition and protein profiles of two genotypically different strains of Escherichia coli O157:H7.
- Author
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Chiou RY, Phillips RD, Zhao P, Doyle MP, and Beuchat LR
- Subjects
- DNA, Bacterial genetics, DNA, Bacterial isolation & purification, Electrophoresis, Gel, Pulsed-Field, Escherichia coli O157 genetics, Escherichia coli O157 growth & development, Fatty Acids analysis, Food Microbiology, Food Preservation, Genotype, Hydrogen-Ion Concentration, Escherichia coli O157 drug effects, Escherichia coli O157 metabolism, Escherichia coli Proteins metabolism, Ethanol pharmacology, Fatty Acids metabolism
- Abstract
Two strains of Escherichia coli O157:H7 were grown in tryptic soy broth (TSB, pH 7.1) supplemented with 0, 2.5, 5.0, 7.5, and 10% ethanol at 30 degrees C for up to 54 h. Growth rates in TSB supplemented with 0, 2.5, and 5.0% ethanol decreased with an increase in ethanol concentration. Growth was not observed in TSB supplemented with 7.5 or 10% ethanol. The pH of TSB containing 5.0% ethanol decreased to 5.8 within 12 h and then increased to 7.0 at 54 h. The ethanol content in TSB supplemented with 2.5 or 5.0% ethanol did not change substantially during the first 36 h of incubation but decreased slightly thereafter, indicating utilization or degradation of ethanol by both strains. Glucose was depleted in TSB supplemented with 0, 2.5, or 5.0% ethanol within 12 h. Cells grown under ethanol stress contained a higher amount of fatty acids. With the exceptions of cis-oleic acid and nonadecanoic acid, larger amounts of fatty acid were present in stationary-phase cells of the two strains grown in TSB supplemented with 5.0% ethanol for 30 h than in cells grown in TSB without ethanol for 22 h. The trans-oleic acid content was 10-fold higher in the cells grown in TSB with 5.0% ethanol than those grown in TSB without ethanol. In contrast, cis-oleic acid was not detected in ethanol-stressed cells but was present at concentrations of 0.32 and 0.36 mg/g of cells of the two strains grown in TSB without ethanol. Protein content was higher in ethanol-stressed cells than in nonstressed cells. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein profiles varied qualitatively as affected by the strain and the presence of ethanol in TSB. An ethanol-mediated protein (28 kDa) was observed in the ethanol-stressed cells but not in control cells. It is concluded that the two test strains of E. coli O157:H7 underwent phenotypic modifications in cellular fatty acid composition and protein profiles in response to ethanol stress. The potential for cross protection against subsequent stresses applied in food preservation technologies as a result of these changes is under investigation.
- Published
- 2004
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