المؤلفون: Miller, Elliot M., Chan, Tat Chung D., Montes-Matamoros, Carlos, Sharif, Omar, Pujo-Menjouet, Laurent, Lindstrom, Michael R.

مصطلحات موضوعية: Quantitative Biology - Neurons and Cognition, Mathematics - Dynamical Systems

الوصف: Many neurodegenerative diseases (NDs) are characterized by the slow spatial spread of toxic protein species in the brain. The toxic proteins can induce neuronal stress, triggering the Unfolded Protein Response (UPR), which slows or stops protein translation and can indirectly reduce the toxic load. However, the UPR may also trigger processes leading to apoptotic cell death and the UPR is implicated in the progression of several NDs. In this paper, we develop a novel mathematical model to describe the spatiotemporal dynamics of the UPR mechanism for prion diseases. Our model is centered around a single neuron, with representative proteins P (healthy) and S (toxic) interacting with heterodimer dynamics (S interacts with P to form two S's). The model takes the form of a coupled system of nonlinear reaction-diffusion equations with a delayed, nonlinear flux for P (delay from the UPR). Through the delay, we find parameter regimes that exhibit oscillations in the P- and S-protein levels. We find that oscillations are more pronounced when the S-clearance rate and S-diffusivity are small in comparison to the P-clearance rate and P-diffusivity, respectively. The oscillations become more pronounced as delays in initiating the UPR increase. We also consider quasi-realistic clinical parameters to understand how possible drug therapies can alter the course of a prion disease. We find that decreasing the production of P, decreasing the recruitment rate, increasing the diffusivity of S, increasing the UPR S-threshold, and increasing the S clearance rate appear to be the most powerful modifications to reduce the mean UPR intensity and potentially moderate the disease progression.
Comment: 35 pages, 11 tables, 13 figures

URL الوصول: http://arxiv.org/abs/2405.16695

المؤلفون: Hui, Xiang^{Aff1, IDs11129023092678_cor1}, Liu, Meng, Chan, Tat

المصدر: Quantitative Marketing and Economics: QME. 21(4):493-517

المؤلفون: Chan, Ken Ka Pang, Ng, Susanna So Shan, Lui, Grace Chung Yan, Leung, Ho Sang, Wong, Ka Tak, Chu, Winnie Chiu Wing, Chan, Tat On, Yiu, Karen Yee Shan, Tso, Eugene Yuk Keung, To, Kin Wang, Ngai, Jenny Chun Li, Yip, Tommy Wing Ho, Lo, Rachel Lai Ping, Ng, Joyce Ka Ching, Ko, Fanny Wai San, Hui, David Shu Cheong^{Aff1, IDs12890023027508_cor16}

المصدر: BMC Pulmonary Medicine. 23(1)

المؤلفون: Yang, Tsung-Han, Liao, Ruey-Ming^{Aff1, Aff2, Aff3, Aff4, Aff5}, Su, Chung-I., Chien, Chun-Yi, Ng, Chan-Tat, Yen, Nai-Shing^{Aff1, Aff3, IDs4159802339160z_cor6}

المصدر: Scientific Reports. 13(1)

المؤلفون: Guo, Huimin, Chan, Tat Fu, Lai, Yat Tung, Wan, Kam Chuen, Chen, Lu, Wong, Wai Po

المصدر: 2020 IEEE International Solid-State Circuits Conference - (ISSCC) Solid-State Circuits Conference - (ISSCC), 2020 IEEE International. :464-466 Feb, 2020

Relation: 2020 IEEE International Solid-State Circuits Conference - (ISSCC)

المؤلفون: Chui, Kawai, Yeh, Kanyu, Chang, Ting-Ting, Ng, Chan-Tat

المصدر: Proceedings of the Annual Meeting of the Cognitive Science Society. 44(44)

مصطلحات موضوعية: Cognitive Neuroscience, Other, fMRI

الوصف: This study investigated the neural substrate of processing gesture-speech semantic variation which arises when the same entity word is uttered along with an iconic gesture that depicts object knowledge or event knowledge of the entity concept, or with a beat gesture that enacts a rhythmic movement, or with a grooming gesture. The fMRI results attested that the observation of gestures with speech, as compared to speech alone, centers on the high-level visual processing and recognition of complex stimuli in the bilateral fusiform gyrus, and the association of various sensory information in spatio-motoric and semantic processing of the inputs in the left inferior/superior parietal gyrus, upon which multiple functional networks are engaged in response to cross-modal semantic variation. The visuo-sensorimotor network of gesture processing with speech does not resemble the processing of hand actions on real objects in the frontal and parietal lobes for the recognition of object-directed motor acts.

وصف الملف: application/pdf

URL الوصول: https://escholarship.org/uc/item/16w7r7gv

المؤلفون: Tsung-Han Yang, Ruey-Ming Liao, Chung-I. Su, Chun-Yi Chien, Chan-Tat Ng, Nai-Shing Yen

المصدر: Scientific Reports, Vol 13, Iss 1, Pp 1-13 (2023)

مصطلحات موضوعية: Medicine, Science

الوصف: Abstract With recent proposal suggesting the multifaceted nature of impulsivity, researchers have been intrigued by the question of whether the impulsive behaviour measured in the traditionally psychological paradigms is unitary. One such paradigm, the differential reinforcement of low-rate responding (DRL), has been used to assess response inhibition, but its underlying mechanism has still been debated. In present research, we examined and differentiated the effects of both response inhibition and interval timing on a multisession DRL-10 s (DRL-10 s) in a large sample of normally developing young adults, as well as with three other measures including the stop-signal reaction task (SSRT), time production task-10 s (TPT-10 s), and the Barrett impulsivity scale-11 (BIS-11). The results showed that behavioural changes existed in DRL. As the task sessions progressed, there was an increase in both reinforcement probability and peak time, but a decrease in burst responses. Most importantly, both principal component analysis and generalized multilevel modeling yielded consistent results that as the task progressed, there was an increasing involvement of the TPT in the late sessions of DRL. However, none of the effect of SSRT was found. In sum, the differential degrees of involvement of the timing process, relative to response inhibition, were observed in DRL.

وصف الملف: electronic resource

Relation: https://doaj.org/toc/2045-2322

URL الوصول: https://doaj.org/article/040059c3353f484397e4663521fe6228

المؤلفون: Liao, Mingjian^{Aff1, Aff2}, Jia, Shuyuan^{Aff1, Aff2}, Wang, Qiang^{Aff1, Aff2}, Chan, Tat Leung^{Aff3, Aff4}, Li, Yawei^{Aff1, Aff2}, Xu, Xuecheng, He, Zhu^{Aff1, Aff2, IDs10494022003920_cor7}

المصدر: Flow, Turbulence and Combustion: An International Journal published in association with ERCOFTAC. 110(3):649-670

المؤلفون: Chui, Kawai, Ng, Chan-Tat, Chang, Ting-Ting

المصدر: In Neuropsychologia 5 November 2023 190

المؤلفون: Liao, Mingjian, He, Zhu, Jia, Shuyuan, Liang, Xiong, Chan, Tat Leung, Li, Yawei, Xu, Xuecheng, Liu, Ting

المصدر: In Case Studies in Thermal Engineering November 2023 51