Publications by authors named "Yichen Wei"

10 Publications

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Fiber-Shaped Triboiontronic Electrochemical Transistor.

Research (Wash D C) 2021 26;2021:9840918. Epub 2021 Apr 26.

Beijing Institute of Nanoenergy and Nanosystems, Chinese Academy of Sciences, Beijing 101400, China.

Contact electrification-activated triboelectric potential offers an efficient route to tuning the transport properties in semiconductor devices through electrolyte dielectrics, i.e., triboiontronics. Organic electrochemical transistors (OECTs) make more effective use of ion injection in the electrolyte dielectrics by changing the doping state of the semiconductor channel. However, the mainstream flexible/wearable electronics and OECT-based devices are usually modulated by electrical signals and constructed in conventional geometry, which lack direct and efficient interaction between the external environment and functional electronic devices. Here, we demonstrate a fiber-shaped triboiontronic electrochemical transistor with good electrical performances, including a current on/off ratio as high as ≈1286 with off-current at ~nA level, the average threshold displacements ( ) of 0.3 mm, the subthreshold swing corresponding to displacement (SS) at 1.6 mm/dec, and excellent flexibility and durability. The proposed triboiontronic electrochemical transistor has great potential to be used in flexible, functional, and smart self-powered electronic textile.
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http://dx.doi.org/10.34133/2021/9840918DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8098052PMC
April 2021

A Pilot Study on the Cutoff Value of Related Brain Metabolite in Chinese Elderly Patients With Mild Cognitive Impairment Using MRS.

Front Aging Neurosci 2021 9;13:617611. Epub 2021 Apr 9.

Department of Rehabilitation, Bao'an Hospital, Southern Medical University, Shenzhen, China.

This cross-sectional study aimed to distinguish patients with mild cognitive impairment (MCI) from patients with normal controls (NCs) by measuring the levels of -acetyl aspartate (NAA), total creatinine (tCr), and choline (Cho) in their hippocampus (HIP) and their posterior cingulate gyrus (PCG) by using proton magnetic resonance spectroscopy (MRS) and to predict the cutoff value on the ratios of metabolites. We further aimed to provide a reference for the diagnosis of MCI in elderly patients in China. About 69 patients who underwent a clinical diagnosis of the MCI group and 67 patients with NCs, the Mini-Mental Status Examination (MMSE) score, the Montreal Cognitive Assessment (MoCA) score, and MRS of the bilateral HIP and bilateral PCG were considered. The ratio of NAA/tCr and Cho/tCr in the bilateral HIP and bilateral PCG was calculated. The relationship between the ratios of metabolites and the scores of MMSE and MoCA was analyzed, and the possible brain metabolite cutoff point for the diagnosis of MCI was evaluated. Compared with the NC group, the scores of MMSE and MoCA in the MCI group decreased significantly ( < 0.05); the ratio of NAA/tCr in the bilateral HIP and bilateral PCG and the ratio of Cho/tCr at the right HIP in the MCI group decreased significantly ( < 0.05); however, there was no significant difference in the ratio of Cho/tCr in the left HIP and bilateral PCG between the two groups ( > 0.05). The correlation coefficient between MMSE/MoCA and the ratio of NAA/tCr was 0.49-0.56 in the bilateral HIP ( < 0.01). The best cutoff value of NAA/creatine (Cr) in the left HIP and the right HIP was 1.195 and 1.19. Sensitivity, specificity, and the Youden index (YDI) in the left HIP and the right HIP were (0.725, 0.803, 0.528) and (0.754, 0.803, 0.557), respectively. The level of metabolites in the HIP and the PCG of patients with MCI and of those with normal subjects has a certain correlation with the score of their MMSE and MoCA. When the value of NAA/tCr in the left HIP and right HIP is <1.19, it suggests that MCI may have occurred. According to this cutoff point, elderly patients with MCI in China could be screened.
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http://dx.doi.org/10.3389/fnagi.2021.617611DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8063036PMC
April 2021

Recurrent and concurrent patterns of regional BOLD dynamics and functional connectivity dynamics in cognitive decline.

Alzheimers Res Ther 2021 01 16;13(1):28. Epub 2021 Jan 16.

The People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, 530021, Guangxi, China.

Background: The brain's dynamic spontaneous neural activity and dynamic functional connectivity (dFC) are both important in supporting cognition, but how these two types of brain dynamics evolve and co-evolve in subjective cognitive decline (SCD) and mild cognitive impairment (MCI) remain unclear. The aim of the present study was to investigate recurrent and concurrent patterns of two types of dynamic brain states correlated with cognitive decline.

Methods: The present study analyzed resting-state functional magnetic resonance imaging data from 62 SCD patients, 75 MCI patients, and 70 healthy controls (HCs). We used the sliding-window and clustering method to identify two types of recurrent brain states from both dFC and dynamic regional spontaneous activity, as measured by dynamic fractional amplitude of low-frequency fluctuations (dfALFF). Then, the occurrence frequency of a dFC or dfALFF state and the co-occurrence frequency of a pair of dFC and dfALFF states among all time points are extracted for each participant to describe their dynamics brain patterns.

Results: We identified a few recurrent states of dfALFF and dFC and further ascertained the co-occurrent patterns of these two types of dynamic brain states (i.e., dfALFF and dFC states). Importantly, the occurrence frequency of a default-mode network (DMN)-dominated dFC state was significantly different between HCs and SCD patients, and the co-occurrence frequencies of a DMN-dominated dFC state and a DMN-dominated dfALFF state were also significantly different between SCD and MCI patients. These two dynamic features were both significantly positively correlated with Mini-Mental State Examination scores.

Conclusion: Our findings revealed novel fMRI-based neural signatures of cognitive decline from recurrent and concurrent patterns of dfALFF and dFC, providing strong evidence supporting SCD as the transition phase between normal aging and MCI. This finding holds potential to differentiate SCD patients from HCs via both dFC and dfALFF as objective neuroimaging biomarkers, which may aid in the early diagnosis and intervention of Alzheimer's disease.
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http://dx.doi.org/10.1186/s13195-020-00764-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7811744PMC
January 2021

Structural and Functional Hippocampal Changes in Subjective Cognitive Decline From the Community.

Front Aging Neurosci 2020 17;12:64. Epub 2020 Mar 17.

Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States.

Background: Recently, subjective cognitive decline (SCD) has been described as the earliest at-risk state of Alzheimer's disease (AD), and drawn attention of investigators. Studies suggested that SCD-community individuals may constitute a more vulnerable population than SCD-clinic patients, therefore, to investigate the early changes of the brain may provide guidance for treatment of the disease. We sought to investigate the changes of structure and functional connectivity alternation of the hippocampus in individuals with SCD recruited from the community using structural and resting-state functional MRI (fMRI).

Methods: Thirty-five SCD patients and 32 healthy controls were recruited. Resting-state fMRI data and high-resolution T1-weighted images were collected. Whole-brain voxel-based morphometry was used to examine the brain structural changes. We also used the hippocampal tail and the whole hippocampus as seeds to investigate functional connectivity alternation in SCD.

Results: Individuals with SCD showed significant gray matter volume decreases in the bilateral hippocampal tails and enlargement of the bilateral paracentral lobules. We also found that individuals with SCD showed decreased hippocampal tail resting-state functional connectivity (rsFC) with the right medial prefrontal cortex (mPFC) and the left temporoparietal junction (TPJ), and decreased whole hippocampus rsFC with the bilateral mPFC and TPJ. These brain region and FC showing significant differences also showed significantly correlation with Montreal Cognitive Assessment (MoCA) scores.

Conclusion: Individuals with SCD recruited from the community is associated with structural and functional changes of the hippocampus, and these changes may serve as potential biomarkers of SCD.

Clinical Trial Registration: The Declaration of Helsinki, and the study was registered in http://www.chictr.org.cn. The Clinical Trial Registration Number was ChiCTR-IPR-16009144.
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http://dx.doi.org/10.3389/fnagi.2020.00064DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7090024PMC
March 2020

LncRNA UCHL1-AS1 prevents cell mobility of hepatocellular carcinoma: a study based on and bioinformatics.

Int J Clin Exp Pathol 2018 1;11(5):2270-2280. Epub 2018 May 1.

Department of Pathology, The First Affiliated Hospital of Guangxi Medical University Nanning 530021, Guangxi Zhuang Autonomous Region, China.

We set out to investigate biological functions and potential molecular mechanisms of long non-coding RNA (lncRNA) in hepatocellular carcinoma (HCC). HCC cell line Bel-7404 was cultured and transfected with antisense to the ubiquitin carboxyl-terminal hydrolase L1 (UCHL1-AS1). Viability and mobility were detected by MTT and wound healing assays. Additionally, enrichment analysis and functional networks of UCHL1-AS1 related genes in HCC were performed. Results showed that high level UCHL1-AS1 could effectively inhibit HCC cell migration. However, there was no significant correlation between overexpressed UCHL1-AS1 and HCC proliferation. Meanwhile, BMP4, CALM3, and HRAS were selected from 204 genes that related to UCHL1-AS1. All of these hub genes play critical roles in HCC occurrence and development. Thus, underlying molecular mechanisms among hub genes and UCHL1-AS1 in HCC might be valuable for prognosis and treatment.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6958276PMC
May 2018

Altered brain structure in women with premenstrual syndrome.

J Affect Disord 2018 03 3;229:239-246. Epub 2018 Jan 3.

Life Science Research Center, School of Life Science and Technology, Xidian University, Xi'an 710071, China; Engineering Research Center of Molecular and Neuro Imaging Ministry of Education, School of Life Science and Technology, Xidian University, Xi'an 710071, China. Electronic address:

Background: Functional brain abnormalities have been noted in premenstrual syndrome (PMS). However, the brain structural alterations related to PMS remain unclear. This study aimed to identify possible abnormalities in gray matter (GM) volumes and structural covariance patterns among PMS patients.

Methods: Structural magnetic resonance imaging data were obtained from 20 PMS patients and 20 healthy controls. Voxel-based morphometry (VBM) analysis was applied to examine GM volumes changes between the two groups. Receiver operating characteristic (ROC) curve was used to investigate the most reliable biomarker for distinguishing PMS patients from health controls based on the intergroup differences. Correlation analysis was then performed to assess relationships between the daily rating of severity of problems (DRSP) and abnormal brain regions. Finally, the regions identified from VBM analysis were served as seeds to characterize the whole-brain structural covariance patterns.

Results: Compared with healthy controls, PMS patients showed increased GM volumes in the precuneus/posterior cingulate cortex (precuneus/PCC) and thalamus, and decreased GM volumes in the insula. The precuneus/PCC exhibited the highest classification power by ROC analysis and positively correlated with the DRSP. Moreover, different patterns of structural covariance in the two groups were mainly located in the dorsolateral prefrontal cortex, anterior cingulate cortex, angular gyrus and hippocampus.

Limitations: This study is limited by a small sample and narrow age range of participants.

Conclusions: Our findings may provide preliminary evidence for brain morphology alterations in PMS patients and contribute to a better understanding of the pathophysiology of PMS.
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http://dx.doi.org/10.1016/j.jad.2017.12.075DOI Listing
March 2018

Face Alignment via Regressing Local Binary Features.

IEEE Trans Image Process 2016 Mar;25(3):1233-45

This paper presents a highly efficient and accurate regression approach for face alignment. Our approach has two novel components: 1) a set of local binary features and 2) a locality principle for learning those features. The locality principle guides us to learn a set of highly discriminative local binary features for each facial landmark independently. The obtained local binary features are used to jointly learn a linear regression for the final output. This approach achieves the state-of-the-art results when tested on the most challenging benchmarks to date. Furthermore, because extracting and regressing local binary features are computationally very cheap, our system is much faster than previous methods. It achieves over 3000 frames per second (FPS) on a desktop or 300 FPS on a mobile phone for locating a few dozens of landmarks. We also study a key issue that is important but has received little attention in the previous research, which is the face detector used to initialize alignment. We investigate several face detectors and perform quantitative evaluation on how they affect alignment accuracy. We find that an alignment friendly detector can further greatly boost the accuracy of our alignment method, reducing the error up to 16% relatively. To facilitate practical usage of face detection/alignment methods, we also propose a convenient metric to measure how good a detector is for alignment initialization.
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http://dx.doi.org/10.1109/TIP.2016.2518867DOI Listing
March 2016

Sketch Matching on Topology Product Graph.

IEEE Trans Pattern Anal Mach Intell 2015 Aug;37(8):1723-9

Sketch matching is the fundamental problem in sketch based interfaces. After years of study, it remains challenging when there exists large irregularity and variations in the hand drawn sketch shapes. While most existing works exploit topology relations and graph representations for this problem, they are usually limited by the coarse topology exploration and heuristic (thus suboptimal) similarity metrics between graphs. We present a new sketch matching method with two novel contributions. We introduce a comprehensive definition of topology relations, which results in a rich and informative graph representation of sketches. For graph matching, we propose topology product graph that retains the full correspondence for matching two graphs. Based on it, we derive an intuitive sketch similarity metric whose exact solution is easy to compute. In addition, the graph representation and new metric naturally support partial matching, an important practical problem that received less attention in the literature. Extensive experimental results on a real challenging dataset and the superior performance of our method show that it outperforms the state-of-the-art.
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http://dx.doi.org/10.1109/TPAMI.2014.2369031DOI Listing
August 2015

Visualizing SNVs to quantify allele-specific expression in single cells.

Nat Methods 2013 Sep 4;10(9):865-7. Epub 2013 Aug 4.

Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA.

We present a FISH-based method for detecting single-nucleotide variants (SNVs) in exons and introns on individual RNA transcripts with high efficiency. We used this method to quantify allelic expression in cell populations and in single cells, and also to distinguish maternal from paternal chromosomes in single cells.
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http://dx.doi.org/10.1038/nmeth.2589DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3771873PMC
September 2013

Outward-looking circular motion analysis of large image sequences.

IEEE Trans Pattern Anal Mach Intell 2005 Feb;27(2):271-7

Department of Computer Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.

This paper presents a novel and simple method of analyzing the motion of a large image sequence captured by a calibrated outward-looking video camera moving on a circular trajectory for large-scale environment applications. Previous circular motion algorithms mainly focus on inward-looking turntable-like setups. They are not suitable for outward-looking motion where the conic trajectory of corresponding points degenerates to straight lines. The circular motion of a calibrated camera essentially has only one unknown rotation angle for each frame. The motion recovery for the entire sequence computes only one fundamental matrix of a pair of frames to extract the angular motion of the pair using Laguerre's formula and then propagates the computation of the unknown rotation angles to the other frames by tracking one point over at least three frames. Finally, a maximum-likelihood estimation is developed for the optimization of the whole sequence. Extensive experiments demonstrate the validity of the method and the feasibility of the application in image-based rendering.
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http://dx.doi.org/10.1109/TPAMI.2005.34DOI Listing
February 2005