Publications by authors named "You Zheng"

125 Publications

CD8 T cells actively penetrate into hepatocytes via CD44/p-ERM/F-actin pathway in autoimmune hepatitis.

J Dig Dis 2021 Apr 29. Epub 2021 Apr 29.

Division of Gastroenterology and Hepatology, Key Laboratory of Gastroenterology and Hepatology, Ministry of Health, State Key Laboratory for Oncogenes and Related Genes, Renji Hospital, School of Medicine, Shanghai Jiao Tong University; Shanghai Institute of Digestive Disease, Shanghai, China.

Aim: Emperipolesis, the cell-in-cell structure, is one of the pathological diagnostic standard of AIH. We have already identified that CD8+ T cells participated in the emperipolesis process in liver tissue of AIH patients. In this study, we aimed to clarify the characteristics and molecular mechanisms of emperipolesis in the patients with AIH in vitro and in mice with α-GalCer-induced acute hepatitis.

Methods: Peripheral blood mononuclear cell (PBMC) of patients with variant chronic liver diseases and healthy controls were co-cultured with hepatic cell line to induce emperipolesis in vitro. Confocal staining was performed to illustrate the cellular types and potential mechanisms of emperipolesis in AIH. In addition, the mouse model of α-GalCer-induced acute hepatitis which mimics human AIH in several features, was used to confirm the role of CD44/p-ERM/F-actin in the emperipolesis process in vivo.

Results: In co-culture system with PBMC and hepatic cell line, emperipolesis was observed most common in the patients with AIH. CD8+ T cells were the major cells participated in the emperipolesis process, and penetrated into hepatocytes actively via CD44/p-ERM/F-actin pathway. As a result, most CD8+ T cells engulfed in hepatocytes undergo self-apoptosis. In α-GalCer-induced acute hepatitis model, emperipolesis was observed around the inflammatory foci, and was inhibited by Ezrin phosphorylation inhibitor NSC668394. Similarly, activated murine CD8+ T cells penetrated into primary hepatocytes via CD44/p-ERM/F-actin pathway in vitro.

Conclusions: CD8+ T cells penetrated into hepatocytes actively via CD44/p-ERM/F-actin signaling pathway and undergo apoptosis, may be a compensative mechanism to attenuate overwhelming immune attack in AIH. This article is protected by copyright. All rights reserved.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1111/1751-2980.12995DOI Listing
April 2021

SARS-CoV-2 spike protein dictates syncytium-mediated lymphocyte elimination.

Cell Death Differ 2021 Apr 20. Epub 2021 Apr 20.

Laboratory of Cell Engineering, Institute of Biotechnology, Beijing, China.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus is highly contagious and causes lymphocytopenia, but the underlying mechanisms are poorly understood. We demonstrate here that heterotypic cell-in-cell structures with lymphocytes inside multinucleate syncytia are prevalent in the lung tissues of coronavirus disease 2019 (COVID-19) patients. These unique cellular structures are a direct result of SARS-CoV-2 infection, as the expression of the SARS-CoV-2 spike glycoprotein is sufficient to induce a rapid (~45.1 nm/s) membrane fusion to produce syncytium, which could readily internalize multiple lines of lymphocytes to form typical cell-in-cell structures, remarkably leading to the death of internalized cells. This membrane fusion is dictated by a bi-arginine motif within the polybasic S1/S2 cleavage site, which is frequently present in the surface glycoprotein of most highly contagious viruses. Moreover, candidate anti-viral drugs could efficiently inhibit spike glycoprotein processing, membrane fusion, and cell-in-cell formation. Together, we delineate a molecular and cellular rationale for SARS-CoV-2 pathogenesis and identify novel targets for COVID-19 therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41418-021-00782-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8056997PMC
April 2021

Spatial learning and memory deficits induced by prenatal glucocorticoid exposure depend on hippocampal CRHR1 and CXCL5 signaling in rats.

J Neuroinflammation 2021 Apr 2;18(1):85. Epub 2021 Apr 2.

Department of Gynecology and Obstetrics and Research Center for Molecular Metabolomics, Xiangya Hospital Central South University, Changsha, 410008, China.

Background: Prenatal synthetic glucocorticoid (sGC) exposure increases the susceptibility to cognitive and affective disorders in postnatal life. We previously demonstrated that prenatal sGC exposure results in an increase in corticotropin-releasing hormone (CRH) receptor type 1 (CRHR1) expression in the hippocampus of rats, and CRHR1 is involved in synapse formation via regulation of C-X-C chemokine ligand 5 (CXCL5) in hippocampus. We sought to investigate that the roles of CRHR1 and CXCL5 in learning and memory impairment caused by prenatal sGC exposure.

Methods: Pregnant rats were administered with saline or dexamethasone (DEX) from gestational day (GD) 14 to GD21. DEX offspring at 2-day old were treated with saline and CRHR1 antagonists (antalarmin and CP154526) for 7 days. Some DEX offspring received intra-hippocampal injection of AAV9 carrying CXCL5 gene. Spatial learning and memory was assessed by Morris water maze test. Immunofluorescence analysis was applied to show synapsin I and PSD95 signals in hippocampus. Synapsin I and PSD95 protein level and CXCL5 concentration were determined by western blotting and ELISA, respectively. Organotypic hippocampal slice cultures were used to investigate the effect of DEX on CXCL5 production in vitro.

Results: Both male and female DEX offspring displayed impairment of spatial learning and memory in adulthood. Synapsin I and PSD95 signals and CXCL5 levels were decreased in DEX offspring. DEX offspring with antalarmin and CP154526 treatment showed improved spatial learning and memory. Antalarmin and CP154526 treatment increased synapsin I and PSD95 signals and CXCL5 concentration in hippocampus. Bilaterally hippocampal injection of AAV9 carrying CXCL5 gene improved the spatial learning and memory and increased CXCL5 concentration and synapsin I and PSD95 levels in hippocampus. DEX dose-dependently suppressed CXCL5 production in cultured hippocammpal slices, which was prevented by antalarmin treatment.

Conclusion: CRHR1 and CXCL5 signaling in the hippocampus are involved in spatial learning and memory deficits caused by prenatal DEX exposure. CRHR1 activation contributes to decreased CXCL5 production in hippocampus induced by prenatal DEX treatment. Our study provides a molecular basis of prenatal GC exposure programming spatial learning and memory.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12974-021-02129-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8019183PMC
April 2021

Designed improvement to T-cell immunotherapy by multidimensional single cell profiling.

J Immunother Cancer 2021 Mar;9(3)

Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas, USA

Background: Adoptive cell therapy based on the infusion of chimeric antigen receptor (CAR) T cells has shown remarkable efficacy for the treatment of hematologic malignancies. The primary mechanism of action of these infused T cells is the direct killing of tumor cells expressing the cognate antigen. However, understanding why only some T cells are capable of killing, and identifying mechanisms that can improve killing has remained elusive.

Methods: To identify molecular and cellular mechanisms that can improve T-cell killing, we utilized integrated high-throughput single-cell functional profiling by microscopy, followed by robotic retrieval and transcriptional profiling.

Results: With the aid of mathematical modeling we demonstrate that non-killer CAR T cells comprise a heterogeneous population that arise from failure in each of the discrete steps leading to the killing. Differential transcriptional single-cell profiling of killers and non-killers identified CD137 as an inducible costimulatory molecule upregulated on killer T cells. Our single-cell profiling results directly demonstrate that inducible CD137 is feature of killer (and serial killer) T cells and this marks a different subset compared with the CD107a (degranulating) subset of CAR T cells. Ligation of the induced CD137 with CD137 ligand (CD137L) leads to younger CD19 CAR T cells with sustained killing and lower exhaustion. We genetically modified CAR T cells to co-express CD137L, in trans, and this lead to a profound improvement in anti-tumor efficacy in leukemia and refractory ovarian cancer models in mice.

Conclusions: Broadly, our results illustrate that while non-killer T cells are reflective of population heterogeneity, integrated single-cell profiling can enable identification of mechanisms that can enhance the function/proliferation of killer T cells leading to direct anti-tumor benefit.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1136/jitc-2020-001877DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7970283PMC
March 2021

Preliminary Study on Predicting Pathological Staging and Immunohistochemical Markers of Rectal Cancer Based on ADC Histogram Analysis.

Acad Radiol 2021 Mar 3. Epub 2021 Mar 3.

Department of Radiology, First Hospital of Lanzhou University, Lanzhou, China; Gansu Intelligent Imaging Medical Engineering Research Center, Lanzhou, China; Accurate Imaging Collaborative Innovation Gansu International Science and Technology Cooperation Base, Lanzhou, China. Electronic address:

Objective: To analyze the correlation between histogram parameters of ADC and pathological staging of rectal cancer and CD31, CD2-40, S-100, and to explore its predictive value.

Materials And Methods: MRI findings of 60 patients with surgically and pathologically proved rectal cancer were analyzed retrospectively. Patients were divided into pT1-2, pT3-4, pN0, pN1-2, G1-2 and G3 groups according to TNM staging of UICC tumors (2019) and WHO classification of digestive system tumors (2019). Cases were divided into CD31 (+) and CD31 (-), CD2-40 (+) and CD4-20 (-), S-100 (+) and S-100 (-) groups according to the expression of immunohistochemical markers. The ROI was delineated layer by layer on the ADC images by Firevoxel software, and the histogram parameters were extracted. The histogram parameters (ADC mean, ADC minimum, ADC maximum, ADC mode, ADC quartile), skewness, kurtosis and entropy were compared between each group. The bivariate logistic regression model was used to predict the tumor staging and immunohistochemical results.

Results: 1. ADC10th, ADC mean and Entropy were higher than pT3-4, ADC mean was higher than pT1-2, Entropy was lower than pT1-2, ADC10th, ADC25th, ADC50th, ADC mean and ADC mode were lower than pT3-40 (-) in CD2-40 (+) group, and the difference was statistically significant (p < 0.05); 2. The lower area of the curve (AUC) of rectal cancer pT, pN and CD2-40 (+) is 0.952 (0.892-1.000), 0.882 (0.791-0.972), 0.913 (0.840-0.985); 3. In the logistic regression model, higher ADC, Ropy and higher pN stages are independent predictors of tumor pT stages (OR = 1.156, 1.144,111.528); p = 0.045, 0.048, 0.002); higher Ropy and lower pT stages are independent predictors of tumor pN stages in the model (OR = 73.939, 0.024; p = 0.019, 0.001); higher ADC and lower differentiation are independent predictors of tumor CD2-40 stages in the model (ADC = 1.17, 0.048, 0.011); and higher Ropy and lower pT stages are independent predictors of tumor CD2-40 stages in the model (ADC = 1.096, 0.094, 0.044).

Conclusion: Histogram analysis based on ADC images has potential value in predicting the pathologic stage and immunohistochemical markers of rectal cancer, and logistic regression model has better diagnostic efficacy than single parameter.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.acra.2021.02.004DOI Listing
March 2021

Role and dynamics of vacuolar pH during cell-in-cell mediated death.

Cell Death Dis 2021 Jan 22;12(1):119. Epub 2021 Jan 22.

Laboratory of Cell Engineering, Institute of Biotechnology, Beijing, China.

The nonautonomous cell death by entosis was mediated by the so-called cell-in-cell structures, which were believed to kill the internalized cells by a mechanism dependent on acidified lysosomes. However, the precise values and roles of pH critical for the death of the internalized cells remained undetermined yet. We creatively employed keima, a fluorescent protein that displays different excitation spectra in responding to pH changes, to monitor the pH dynamics of the entotic vacuoles during cell-in-cell mediated death. We found that different cells varied in their basal intracellular pH, and the pH was relatively stable for entotic vacuoles containing live cells, but sharply dropped to a narrow range along with the inner cell death. In contrast, the lipidation of entotic vacuoles by LC3 displayed previously underappreciated complex patterns associated with entotic and apoptotic death, respectively. The pH decline seemed to play distinct roles in the two types of inner cell deaths, where apoptosis is preceded with moderate pH decline while a profound pH decline is likely to be determinate for entotic death. Whereas the cancer cells seemed to be lesser tolerant to acidified environments than noncancerous cells, manipulating vacuolar pH could effectively control inner cell fates and switch the ways whereby inner cell die. Together, this study demonstrated for the first time the pH dynamics of entotic vacuoles that dictate the fates of internalized cells, providing a rationale for tuning cellular pH as a potential way to treat cell-in-cell associated diseases such as cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41419-021-03396-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7822940PMC
January 2021

An Attention-guided Deep Neural Network with Multi-scale Feature Fusion for Liver Vessel Segmentation.

IEEE J Biomed Health Inform 2020 Dec 2;PP. Epub 2020 Dec 2.

Liver vessel segmentation is fast becoming a key instrument in the diagnosis and surgical planning of liver diseases. In clinical practice, liver vessels are normally manual annotated by clinicians on each slice of CT images, which is extremely laborious. Several deep learning methods existed for liver vessel segmentation, however, promoting the performance of segmentation remains a major challenge due to the large variations and complex structure of liver vessels. Previous methods mainly using existing UNet architecture, but not all features of the encoder are useful for segmentation and some even cause interferences. To overcome this problem, we propose a novel deep neural network for liver vessel segmentation, called LVSNet, which employed special designs to obtain the accurate structure of the liver vessel. Specifically, we design Attention-Guided Concatenation (AGC) module to adaptively select the useful context features from low-level features guided by high-level features. The proposed AGC module focuses on capturing rich complemented information to obtain more details. In addition, we introduce an innovative multi-scale fusion block by constructing hierarchical residual-like connections within one single residual block, which is great importance for effectively linking the local blood vessel fragments together. Furthermore, we construct a new dataset containing 40 thin thickness cases (0.625mm) which consist of CT volumes and annotated vessels. To evaluate the effectiveness of the method with minor vessel, we also propose an automatic stratification method to split major and minor liver vessels. Extensive experimental results demonstrate that the proposed LVSNet outperforms previous methods on liver vessel segmentation datasets. Additionally, we conduct a series of ablation studies that comprehensively support the superiority of the underlying concepts.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1109/JBHI.2020.3042069DOI Listing
December 2020

AI-assisted CT imaging analysis for COVID-19 screening: Building and deploying a medical AI system.

Appl Soft Comput 2021 Jan 10;98:106897. Epub 2020 Nov 10.

State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, China.

The sudden outbreak of novel coronavirus 2019 (COVID-19) increased the diagnostic burden of radiologists. In the time of an epidemic crisis, we hope artificial intelligence (AI) to reduce physician workload in regions with the outbreak, and improve the diagnosis accuracy for physicians before they could acquire enough experience with the new disease. In this paper, we present our experience in building and deploying an AI system that automatically analyzes CT images and provides the probability of infection to rapidly detect COVID-19 pneumonia. The proposed system which consists of classification and segmentation will save about 30%-40% of the detection time for physicians and promote the performance of COVID-19 detection. Specifically, working in an interdisciplinary team of over 30 people with medical and/or AI background, geographically distributed in Beijing and Wuhan, we are able to overcome a series of challenges ( data discrepancy, testing time-effectiveness of model, data security, etc.) in this particular situation and deploy the system in four weeks. In addition, since the proposed AI system provides the priority of each CT image with probability of infection, the physicians can confirm and segregate the infected patients in time. Using 1,136 training cases (723 positives for COVID-19) from five hospitals, we are able to achieve a sensitivity of 0.974 and specificity of 0.922 on the test dataset, which included a variety of pulmonary diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.asoc.2020.106897DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7654325PMC
January 2021

SARS-CoV-2 Targets by the pscRNA Profiling of ACE2, TMPRSS2 and Furin Proteases.

iScience 2020 Nov 28;23(11):101744. Epub 2020 Oct 28.

Institute of Biotechnology, 20 Dongda Street, Beijing 100071, P.R. China.

The cellular targets of SARS-CoV-2, the novel coronavirus causing the COVID-19 pandemic, is still rudimentary. Here, we incorporated the protein information to analyze the expression of ACE2, the SARS-CoV-2 receptor, together with co-factors, TMPRSS2 and Furin, at single-cell level , which we called protein-proofed single-cell RNA (pscRNA) profiling. Systemic analysis across 36 tissues revealed a rank list of candidate cells potentially vulnerable to SARS-CoV-2. The top targets are lung AT2 cells and macrophages, then cardiomyocytes and adrenal gland stromal cells, followed by stromal cells in testis, ovary, and thyroid, whereas the kidney proximal tubule cells, cholangiocytes, and enterocytes are less likely to be the primary SARS-CoV-2 targets. Actually, the stomach may constitute a physical barrier against SARS-CoV-2 as the acidic environment (pH < 2.0) could completely inactivate SARS-CoV-2 pseudo-viruses. Together, we provide a comprehensive view on the potential SARS-CoV-2 targets by pscRNA profiling.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.isci.2020.101744DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7591870PMC
November 2020

p53-dependent elimination of aneuploid mitotic offspring by entosis.

Cell Death Differ 2021 Feb 27;28(2):799-813. Epub 2020 Oct 27.

Laboratory of Cell Engineering, Institute of Biotechnology, 20 Dongda Street, Beijing, 100071, China.

Entosis was proposed to promote aneuploidy and genome instability by cell-in-cell mediated engulfment in tumor cells. We reported here, in epithelial cells, that entosis coupled with mitotic arrest functions to counteract genome instability by targeting aneuploid mitotic progenies for engulfment and elimination. We found that the formation of cell-in-cell structures associated with prolonged mitosis, which was sufficient to induce entosis. This process was controlled by the tumor suppressor p53 (wild-type) that upregulates Rnd3 expression in response to DNA damages associated with prolonged metaphase. Rnd3-compartmentalized RhoA activities accumulated during prolonged metaphase to drive cell-in-cell formation. Remarkably, this prolonged mitosis-induced entosis selectively targets non-diploid progenies for internalization, blockade of which increased aneuploidy. Thus, our work uncovered a heretofore unrecognized mechanism of mitotic surveillance for entosis, which eliminates newly born abnormal daughter cells in a p53-dependent way, implicating in the maintenance of genome integrity.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41418-020-00645-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7862607PMC
February 2021

Diffractive Beam Shaper for Multiwavelength Lasers for Flow Cytometry.

Cytometry A 2021 Feb 4;99(2):194-204. Epub 2020 Nov 4.

State Key Laboratory of Precision Measurement Technology and Instrument, Tsinghua University, Beijing, China.

Illumination spot in a flow cytometer is a crucial factor determining the measurement accuracy and stability. The traditional mechanism is to precisely calibrate multiple optical components to convert circular Gaussian beams into elliptical Gaussian beams, making it difficult to shape multiwavelength lasers simultaneously. A diffractive beam shaper for multicolor lasers with high simplicity, only containing one diffractive optical element and one focusing lens is created in this work. It can produce rectangular spots, of which the number, the sizes, and the positions are accurately determined by the incident wavelengths. Demonstrated in the customized microflow cytometer, the coefficient of variations (CV) of the optical signals by the beam shaper are 3.6-6.5%, comparable to those derived from the commercial instrument with 3.3-6.3% CVs. Benefiting from the narrow rectangular spots and the flexibility of diffractively shaped lasers, the measurement of bead sizes with 4-15 μm diameters and the real-time detection of flow velocity from 0.79 to 9.50 m/s with the CV of <5% are achieved. © 2020 International Society for Advancement of Cytometry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cyto.a.24240DOI Listing
February 2021

Industrial Structure Adjustment and Regional Green Development from the Perspective of Mineral Resource Security.

Int J Environ Res Public Health 2020 09 24;17(19). Epub 2020 Sep 24.

School of Economics and Management, China University of Geosciences, Wuhan 430074, China.

Mineral resource security is the premise and foundation of the regional green rise strategy. And the adjustment of industrial structure is an effective way to relieve the pressure of the current green economy transformation. Based on the Shift-share Method and the Spatial Durbin model, this paper takes 30 regions in China from 2006 to 2017 as examples to study the impact of industrial structure adjustment on China's green development from the perspective of mineral resource security. The empirical results show that: China is still in the process of industrial transfer. The dynamic effect of industrial structure promotes green development from the perspective of mineral resource security, while its static effect inhibits green development from the perspective of mineral resource security. The spatial spillover effect of the industrial structure affecting green development from the perspective of mineral resource security is significant. The static structural effect of the tertiary industry promotes the green development of the region, and it has a significant negative impact on neighboring areas, while the secondary industry's static structural effect has the opposite effect.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijerph17196978DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7579431PMC
September 2020

Mechanical Ring Interfaces between Adherens Junction and Contractile Actomyosin to Coordinate Entotic Cell-in-Cell Formation.

Cell Rep 2020 08;32(8):108071

Laboratory of Cell Engineering, Institute of Biotechnology, 20 Dongda Street, Beijing 100071, China. Electronic address:

Entosis is a cell-in-cell (CIC)-mediated death program. Contractile actomyosin (CA) and the adherens junction (AJ) are two core elements essential for entotic CIC formation, but the molecular structures interfacing them remain poorly understood. Here, we report the characterization of a ring-like structure interfacing between the peripheries of invading and engulfing cells. The ring-like structure is a multi-molecular complex consisting of adhesive and cytoskeletal proteins, in which the mechanical sensor vinculin is highly enriched. The vinculin-enriched structure senses mechanical force imposed on cells, as indicated by fluorescence resonance energy transfer (FRET) analysis, and is thus termed the mechanical ring (MR). The MR actively interacts with CA and the AJ to help establish and maintain polarized actomyosin that drives cell internalization. Vinculin depletion leads to compromised MR formation, CA depolarization, and subsequent CIC failure. In summary, we suggest that the vinculin-enriched MR, in addition to CA and AJ, is another core element essential for entosis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2020.108071DOI Listing
August 2020

Reliable Control for Flexible Spacecraft Systems With Aperiodic Sampling and Stochastic Actuator Failures.

IEEE Trans Cybern 2020 Aug 20;PP. Epub 2020 Aug 20.

This article addresses the aperiodic sampled-data control problem for flexible spacecraft with stochastic actuator failures. Flexible spacecraft dynamics are approximated by a group of T-S fuzzy models due to strong nonlinearity, and the multi-stochastic failures of spacecraft are depicted by a time-continuous and state-discrete Markov chain. To reduce the design conservativeness, a membership-sampling-dependent Lyapunov-Krasovskii functional (MSDLKF) is introduced to utilize the information of fuzzy membership functions and aperiodic sampling modes. Furthermore, a number of reliable fuzzy controllers are designed to obtain the exponential attitude stabilization under the circumstances of stochastic failures. At the same time, disturbance attenuation is ensured. The solution of the fuzzy controller gains can be obtained by solving a set of linear matrix inequalities (LMIs). In the end, an example of the practical flexible spacecraft system is given to illustrate the feasibility and validity of the proposed fuzzy control methods.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1109/TCYB.2020.3008045DOI Listing
August 2020

Treatment of severe COVID-19 with human umbilical cord mesenchymal stem cells.

Stem Cell Res Ther 2020 08 18;11(1):361. Epub 2020 Aug 18.

Department of Pulmonary and Critical Care Medicine, the Second Affiliated Hospital of Nanjing Medical University, Address: No. 121 Jiangjiayuan Rd, Gulou District, Nanjing, 210011, Jiangsu, China.

Background: COVID-19 is a highly infectious respiratory disease. No therapeutics have yet been proven effective for treating severe COVID-19.

Objectives: To determine whether human umbilical cord mesenchymal stem cell infusion may be effective and safe for the treatment of severe COVID-19.

Methods: Patients with severe COVID-19 were randomly divided into 2 groups: the standard treatment group and the standard treatment plus hUC-MSC infusion group. The incidence of progression from severe to critical illness, 28-day mortality, clinical symptom improvement, time to clinical symptom improvement, hematologic indicators including C-reactive protein, lymphocyte number, and interleukin 6, and imaging changes were observed and compared between the two groups.

Measurements And Main Results: The incidence of progression from severe to critical illness and the 28-day mortality rate were 0 in the hUC-MSC treatment group, while 4 patients in the control group deteriorated to critical condition and received invasive ventilation; 3 of them died, and the 28-day mortality rate was 10.34%. In the hUC-MSC treatment group, the time to clinical improvement was shorter than that in the control group. Clinical symptoms of weakness and fatigue, shortness of breath, and low oxygen saturation obviously improved beginning on the third day of stem cell infusion and reached a significant difference on day 7. CRP and IL-6 levels were significantly lower from day 3 of infusion, the time for the lymphocyte count to return to the normal range was significantly faster, and lung inflammation absorption was significantly shorter on CT imaging in the hUC-MSC group than in the control group.

Conclusions: Intravenous transplantation of hUC-MSCs is a safe and effective method that can be considered a salvage and priority treatment option for severe COVID-19.

Trial Registration: Chinese Clinical Trial Registration; ChiCTR2000031494; Registered on 2 April 2020; http:// www.medresman.org.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13287-020-01875-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7432540PMC
August 2020

Ultralow Quiescent Power-Consumption Wake-Up Technology Based on the Bionic Triboelectric Nanogenerator.

Adv Sci (Weinh) 2020 Jun 11;7(12):2000254. Epub 2020 May 11.

Department of Precision Instrument Tsinghua University Beijing 100084 P. R. China.

Wake-up circuits in smart microsystems make huge contributions to energy conservation of electronic networks in unmanned areas, which still require higher pressure-triggering sensitivity and lower power consumption. In this work, a bionic triboelectric nanogenerator (bTENG) is developed to serve as a self-powered motion sensor in the wake-up circuit, which captures slight mechanical disturbances and overcomes the drawback of conventional self-powered motion sensors in the wake-up circuit that the circuit can only be triggered when a considerable pressure is applied on the sensor. The bTENG mimics the structure of plants and the addition of the leaf-shaped tentacle structures can increase the electrical outputs by four times, which largely extends the detection range of the wake-up circuit. The bTENG can detect both noncontact and contact mechanical disturbances; and voltages generated from both situations can trigger the wake-up system. Moreover, the specially designed circuit that is compatible with the bTENG can help more accurately control the wake-up system and prolong the battery life of the electronic networks to 12.4 times. An intrusion detection system is established in the wake-up circuit to distinguish human motion and judge the scene. This work opens new horizons for wake-up technologies, and provides new routes for persistent sensing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/advs.202000254DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7312437PMC
June 2020

Shenhuang granule in the treatment of severe coronavirus disease 2019 (COVID-19): study protocol for an open-label randomized controlled clinical trial.

Trials 2020 Jun 24;21(1):568. Epub 2020 Jun 24.

Department of Emergency Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, No.1095 Jie Fang Avenue, Hankou, Wuhan, 430030, Hubei, China.

Background: Currently, coronavirus disease 2019 (COVID-19) is continuously and rapidly circulating, causing heavy damage on public health. No effective antiviral treatment has been proved thus far. Traditional Chinese medicine (TCM) has been widely applied in the treatment of a variety of infection diseases in China, hoping to produce clinical effects and reduce the use of antibiotics and glucocorticoid. The aim of this study is to evaluate the efficacy and safety of Shenhuang granule in treatment of severe COVID-19.

Methods/design: This multicenter, open-label randomized controlled trial is conducted in 160 participants with severe COVID-19. The participants will be randomly (1:1) divided into treatment group or control group. All participants are given standard therapy at the same time. The experiment will receive Shenhuang granule treatment twice a day for 14 days. The clinical indicators of patients will be assessed at baseline and at 3, 5, 7, and 14 days after treatment initiation. The primary outcome is 14-day clinical outcome. Adverse events will be monitored throughout the trial.

Discussion: This will be the first randomized controlled trial, which evaluate the effect of Shenhuang granule in patients with severe COVID-19 in China. The results of this trial may not only provide evidence-based recommendations to clinicians to treat severe COVID-19, but also enrich the theory and practice of TCM in treating infectious diseases.

Trial Registration: Chinese Clinical Trial Registry, ChiCTR2000029777. Registered on 13 February 2020.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s13063-020-04498-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7312108PMC
June 2020

Symmetric Sodium-Ion Battery Based on Dual-Electron Reactions of NASICON-Structured NaMnTi(PO) Material.

ACS Appl Mater Interfaces 2020 Jul 25;12(27):30328-30335. Epub 2020 Jun 25.

Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, Guangdong Engineering Technology Research Center of Efficient Green Energy and Environment Protection Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, P. R. China.

Symmetric sodium-ion batteries possess promising features such as low cost, easy manufacturing process, and facile recycling post-process, which are suitable for the application of large-scale stationary energy storage. Herein, we proposed a symmetric sodium-ion battery based on dual-electron reactions of a NASICON-structured NaMnTi(PO) material. The NaMnTi(PO) electrode can deliver a stable capacity of up to 160 mAh g with a Coulombic efficiency of 97% at 0.1 C by utilizing the redox reactions of Ti, Mn, and Mn. This is the first time to investigate the symmetric sodium-ion full cell using NaMnTi(PO) as both cathode and anode in the organic electrolyte, demonstrating excellent reversibility and cycling performance with voltage plateaus of about 1.4 and 1.9 V. The full cell exhibits a reversible capacity of 75 mAh g at 0.1 C and an energy density of 52 Wh kg. In addition, both X-ray diffraction (XRD) analysis and first-principles calculations are employed to investigate the sodiation mechanism and structural evolution. The current research provides a feasible strategy for the symmetric sodium-ion batteries to achieve high energy density.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acsami.0c05784DOI Listing
July 2020

PCDH7 Inhibits the Formation of Homotypic Cell-in-Cell Structure.

Front Cell Dev Biol 2020 8;8:329. Epub 2020 May 8.

Laboratory of Cell Engineering, Institute of Biotechnology, Beijing, China.

Though homotypic cell-in-cell (hoCIC) structures are implicated in the development and progression of multiple human tumors, the molecular mechanisms underlying their formation remain poorly understood. We found that the expression of Protocadherin-7 (PCDH7), an integral membrane protein, was negatively associated with the formation of hoCIC structures. Overexpression of efficiently inhibits, while its depletion significantly enhances, hoCIC formation, which was attributed to its regulation on intercellular adhesion and contractile actomyosin as well. Via directly interacting with and inactivating PP1α, a protein phosphatase that dephosphorylates pMLC2, PCDH7 increases the level of pMLC2 leading to enhanced actomyosin at the intercellular region and compromised hoCIC formation. Remarkably, enhanced anchorage-independent cell growth in a hoCIC-dependent manner. Together, we identified PCDH7 as the first membrane protein that inhibits hoCIC formation to promote tumor growth.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fcell.2020.00329DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7225324PMC
May 2020

Liver transcriptome analysis and cortisol immune-response modulation in lipopolysaccharide-stimulated in channel catfish (Ictalurus punctatus).

Fish Shellfish Immunol 2020 Jun 14;101:19-50. Epub 2020 Mar 14.

Freshwater Fisheries Research Institute of Jiangsu Province, Nanjing, 210017, China. Electronic address:

Channel catfish (Ictalurus punctatus) is an important aquaculture species in China. In channel catfish, diseases such as haemorrhagic, sepsis and tail-rot disease are all caused by bacteria as general in China. Most of the pathogenic bacteria are Gram-negative bacteria. Liver transcriptome analysis of the co-injection of cortisol and lipopolysaccharide (LPS) was performed in this study. Preliminary evidence from the results suggest that after the emergence of immune stress, cortisol will up-regulate the complement cascade pathway, down-regulate the coagulation cascade pathway, down-regulate the platelet activation pathway, down-regulate antigen presentation pathway, and show complex regulation relationship to inflammatory factors. At 12 h, the number of differential genes regulated by cortisol was about half less than the number of differential genes regulated by LPS. At 24 h, there was no significant difference between the number of differential genes regulated by cortisol and LPS, but the types of differential genes vary widely. KEGG enrichment analysis found that cortisol regulated LPS-stimulated immune responses mainly focus on cytokines, complement and coagulation cascades pathways, antigen presentation pathways, haematopoiesis, and inflammation. It is suggested that there may be some strategic choice in the regulation of immune response by cortisol. These results will help understand the pathogenesis and host defence system in bacterial disease caused by Gram-negative bacteria.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.fsi.2020.03.024DOI Listing
June 2020

Design and Fabrication of a Novel MEMS Relay with Low Actuation Voltage.

Micromachines (Basel) 2020 Feb 7;11(2). Epub 2020 Feb 7.

MEMS Institute of Zibo National High-Tech Industrial Development Zone, Zibo 255000, China.

Compared with conventional solid-state relays, micro-electro mechanical system (MEMS) relays have the advantages of high isolation, low contact resistance, low power consumption, and abrupt switching characteristics. Nevertheless, the widespread application of MEMS relays has been limited due to the issue of the conflict between low actuation voltages and high device performance. This article presents a novel cantilever MEMS relay with an embedded contact electrode which helps to achieve a low actuation voltage (below 8 V) and high restoring force simultaneously. Meanwhile, the contact resistance is as low as around 0.4 Ω and the reliability is verified. To thoroughly investigate and analyze the novel cantilever MEMS relay, a static theoretical model of the structure was developed. Based on the model, the cantilever MEMS relay was designed and optimized. Then, the relays were fabricated by the bulk-silicon micromachining process based on the silicon-glass anodic bonding technology. Finally, the switching performance of the novel cantilever MEMS relay was measured. Experimental results demonstrate that the proposed MEMS relay has a low actuation voltage below 8 V and high performance, which is in good agreement with the simulation results, and shows significant advantages when compared with previous reports. Therefore, the proposed MEMS relay with an embedded contact electrode is promising in practical applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/mi11020171DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7074599PMC
February 2020

Protein content of amaranth and quinoa starch plays a key role in their ability as Pickering emulsifiers.

Food Chem 2020 Jun 21;315:126246. Epub 2020 Jan 21.

Department of Food Science, College of Agriculture and Life Sciences, Cornell University, 243 Stocking Hall, Ithaca, NY 14853, USA. Electronic address:

Growing concerns about the safety of using synthetic surfactants to stabilize food emulsions have inspired a trend towards the use of natural ingredients like starch as alternative food stabilizers in what are called Pickering emulsions. The hydrophilicity of commercially available starches, however, necessitates further chemical treatment to increase their hydrophobicity and emulsifying ability. Here we demonstrate an alkaline isolation method to extract amaranth and quinoa starch from flour while retaining a high protein content, which gives these materials an emulsifying ability comparable to octenyl succinylated starches in the literature. We highlight the key role played by protein by showing that a serial reduction of the protein content leads to a parallel reduction in emulsifying ability, and that pH affects this ability. Our method of retaining proteins naturally present in amaranth and quinoa not only bolsters their nutritional profile but also takes advantage of these proteins' native hydrophobicity for improved emulsification.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.foodchem.2020.126246DOI Listing
June 2020

Sheathless Inertial Focusing Chip Combining a Spiral Channel with Periodic Expansion Structures for Efficient and Stable Particle Sorting.

Anal Chem 2020 01 3;92(2):1833-1841. Epub 2020 Jan 3.

State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument , Tsinghua University , Beijing 100084 , China.

Efficient and reliable manipulation of biological particles is crucial in medical diagnosis and chemical synthesis. Inertial microfluidic devices utilizing passive hydrodynamic forces in the secondary flow have drawn considerable attention for their high throughputs, low costs, and harmless particle manipulation. However, as the dominant mechanism, the inertial lift force is difficult to quantitatively analyze because of the uncertainties of its magnitude and direction. The equilibrium position of particles varies along the migration process, thus inducing the instabilities of particle separation. Herein, we present a designable inertial microfluidic chip combining a spiral channel with periodic expansion structures for the sheathless separation of particles with different sizes. The stable vortex-induced lift force arising from the periodic expansion and the Dean drag force significantly enhanced the focusing process and determined the final equilibrium position. The experimental results showed that over 99% of target particles could be isolated with the high target sample purity of 86.12%. In the biological experiment, 93.5% of the MCF-7, 89.5% of the Hela, and 88.6% of the A549 cells were steadily recovered with excellent viabilities to verify the potential of the device in dealing with biological particles over a broad range of throughputs. The device presented in this study can further serve as a lab-on-chip platform for liquid biopsy and diagnostic analysis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/acs.analchem.9b03692DOI Listing
January 2020

Whole-Liver Apparent Diffusion Coefficient Histogram Analysis for the Diagnosis and Staging of Liver Fibrosis.

J Magn Reson Imaging 2020 06 15;51(6):1745-1754. Epub 2019 Nov 15.

First Clinical Medical College of Lanzhou University, Lanzhou, Gansu, China.

Background: Conventional diffusion-weighted imaging is limited in the quantitative evaluation of liver fibrosis, and whole-liver apparent diffusion coefficient (ADC) histogram analysis might contribute to the diagnosis and staging of liver fibrosis.

Purpose: To explore the value of whole-liver ADC histogram parameters in the diagnosis and staging of liver fibrosis.

Study Type: Retrospective.

Population: Twenty individuals with no liver disease and 86 patients with liver fibrosis, including 30 with chronic viral hepatitis, 29 with autoimmune hepatitis, and 27 with unexplained liver fibrosis patients.

Field Strength/sequence: 3.0T/T -weighted, T -weighted, and diffusion-weighted images.

Assessment: A region of interest (ROI) was drawn in each slice of the diffusion-weighted images. Whole-liver histogram parameters were obtained with dedicated software by accumulating all ROIs. The effectiveness of the parameters in differentiating stage 1 or greater (≥F1), stage 2 or greater (≥F2), and stage 3 or greater (≥F3) liver fibrosis was assessed.

Statistical Tests: Mann-Whitney U-test and receiver operating characteristic curve analysis.

Results: Kurtosis, entropy, skewness, mode, and 90 and 75 percentiles exhibited significant differences among the pathological fibrosis stages (P < 0.05). Kurtosis was found to be the most meaningful parameter in differentiating fibrosis stages of the viral hepatitis, autoimmune hepatitis, and unexplained liver fibrosis group (area under the curve) (AUC = 0.793, 0.771, 0.798, respectively). In the combined liver fibrosis group, kurtosis achieved the highest AUC (0.801; 95% confidence interval [CI]: 0.702-0.900; sensitivity: 0.750; specificity: 0.850; positive likelihood ratio: 4.953; negative likelihood ratio: 0.302; positive predictive value: 0.946; negative predictive value: 0.486), with a cutoff value of 1.817, in differentiating fibrosis stage ≥F1.

Data Conclusion: Kurtosis, entropy, skewness, mode, and 90 and 75 percentiles may contribute to the diagnosis and staging of liver fibrosis, especially kurtosis.

Level Of Evidence: 4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:1745-1754.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jmri.26987DOI Listing
June 2020

Subtype-Based Prognostic Analysis of Cell-in-Cell Structures in Early Breast Cancer.

Front Oncol 2019 20;9:895. Epub 2019 Sep 20.

Laboratory of Cell Engineering, Institute of Biotechnology, Beijing, China.

Though current pathological methods are greatly improved, they provide rather limited functional information. Cell-in-cell structures (CICs), arising from active cell-cell interaction, are functional surrogates of complicated cell behaviors within heterogeneous cancers. In light of this, we performed the subtype-based CIC profiling in human breast cancers by the "EML" multiplex staining method, and accessed their values as prognostic factors by Cox univariate, multivariate, and nomogram analysis. CICs were detected in cancer specimens but not in normal breast tissues. A total of five types of CICs were identified with one homotypic subtype (91%) and four heterotypic subtypes (9%). Overall CICs (oCICs) significantly associated with patient overall survival (OS) ( = 0.011) as an independent protective factor (HR = 0.423, 95% CI, 0.227-0.785; = 0.006). Remarkably, three CICs subtypes (TiT, TiM, and MiT) were also independent prognostic factors. Among them, higher TiT, from homotypic cannibalism between tumor cells, predicted longer patient survival (HR = 0.529, 95% CI, 0.288-0.973; = 0.04) in a way similar to that of oCICs and that (HR = 0.524, 95% CI, 0.286-0.962; = 0.037) of heterotypic TiM (tumor cell inside macrophage); conversely, the presence of MiT (macrophage inside tumor cell) predicted a death hazard of 2.608 (95% CI, 1.344-5.063; = 0.05). Moreover, each CIC subtype tended to preferentially affect different categories of breast cancer, with TiT ( < 0.0001) and oCICs ( = 0.008) targeting luminal B (Her2), TiM ( = 0.011) targeting HR (Her2/HR and TNBC), and MiT targeting luminal A ( = 0.017) and luminal B (Her) ( = 0.006). Furthermore, nomogram analysis suggested that CICs impacted patient outcomes in contributions comparable (for oCICs, TiT, and TiM), or even superior (for MiT), to TNM stage and breast cancer subtype, and incorporating CICs improved nomogram performance. Together, we propose CICs profiling as a valuable way for prognostic analysis of breast cancer and that CICs and their subtypes, such as MiT, may serve as a type of novel functional markers assisting clinical practices.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fonc.2019.00895DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6798043PMC
September 2019

Multimorphological top-hat-based multiscale target classification algorithm for real-time image processing.

Appl Opt 2019 Aug;58(22):6045-6056

The traditional top-hat method is a commonly used method that quickly separates targets from a background. It is used for its fast processing speed and wide range of applications on programmable hardware. However, in some important fields such as microfluidic control, medicine, aerospace, and optical measurement, the observed targets are often spotted with different sizes. The formation mechanism of multiscale spots varies from each other so that they can not be successfully extracted and classified by the traditional top-hat method. To ensure the integrity of targets with a specific size and suppressed noise, the imaging mechanism of different types of spots are studied, and an improved top-hat method with a gray-scale value-based transform is proposed. Compared with the traditional top-hat method, the proposed algorithm is more effective in completely removing unwanted spots. The calculated results of the simulated and real images verify the effectiveness of the double top-hat method in extracting targets with a specific size. Additionally, the resolution of this method is up to the parameter k, which has been discussed in this paper. Furthermore, a multi-top-hat algorithm is presented to distinguish spots of different sizes, and it could be used for real-time multiscale target detection and tracking, as well as real-time multiscale target detection and tracking.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/AO.58.006045DOI Listing
August 2019

Laser Fabrication of Graphene-Based Flexible Electronics.

Adv Mater 2020 Apr 22;32(15):e1901981. Epub 2019 Aug 22.

State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University, Beijing, 100084, China.

Recent years have witnessed the rise of graphene and its applications in various electronic devices. Specifically, featuring excellent flexibility, transparency, conductivity, and mechanical robustness, graphene has emerged as a versatile material for flexible electronics. In the past decade, facilitated by various laser processing technologies, including the laser-treatment-induced photoreduction of graphene oxides, flexible patterning, hierarchical structuring, heteroatom doping, controllable thinning, etching, and shock of graphene, along with laser-induced graphene on polyimide, graphene has found broad applications in a wide range of electronic devices, such as power generators, supercapacitors, optoelectronic devices, sensors, and actuators. Here, the recent advancements in the laser fabrication of graphene-based flexible electronic devices are comprehensively summarized. The various laser fabrication technologies that have been employed for the preparation, processing, and modification of graphene and its derivatives are reviewed. A thorough overview of typical laser-enabled flexible electronic devices that are based on various graphene sources is presented. With the rapid progress that has been made in the research on graphene preparation methodologies and laser micronanofabrication technologies, graphene-based electronics may soon undergo fast development.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/adma.201901981DOI Listing
April 2020

Extrinsic Parameter Calibration Method for a Visual/Inertial Integrated System with a Predefined Mechanical Interface.

Sensors (Basel) 2019 Jul 12;19(14). Epub 2019 Jul 12.

State Key Laboratory of Precision Measurement Technology and Instruments, Tsinghua University, Beijing 100084, China.

For a visual/inertial integrated system, the calibration of extrinsic parameters plays a crucial role in ensuring accurate navigation and measurement. In this work, a novel extrinsic parameter calibration method is developed based on the geometrical constraints in the object space and is implemented by manual swing. The camera and IMU frames are aligned to the system body frame, which is predefined by the mechanical interface. With a swinging motion, the fixed checkerboard provides constraints for calibrating the extrinsic parameters of the camera, whereas angular velocity and acceleration provides constraints for calibrating the extrinsic parameters of the IMU. We exploit the complementary nature of both the camera and IMU, of which the latter assists in the checkerboard corner detection and correction while the former suppresses the effects of IMU drift. The results of the calibration experiment reveal that the extrinsic parameter accuracy reaches 0.04° for each Euler angle and 0.15 mm for each position vector component (1σ).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/s19143086DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6679094PMC
July 2019

CMOS imager non-uniformity response correction-based high-accuracy spot target localization.

Appl Opt 2019 Jun;58(16):4560-4568

High-accuracy spot target detection based on a complementary metal-oxide semiconductor (CMOS) image sensor, such as astronomy magnitude, medicine, and astronomy photometrics, needs accurate pixel response. Because pixels have different silicon structures and read outputting, each pixel has non-uniformity response with specific illumination. The flat-field correction of a CMOS image sensor is crucial before image processing. In this work, a flat-field model and correction method based on spot scale areas of CMOS image sensor pixel response are proposed. Compared with traditional full-plane calibration, this method aims at spot areas to fit most selected normal pixels' mean response curve with different light intensities and exposure times, which can guarantee spot imaging areas with higher accurate pixel response. Finally, the accuracy of this flat-field correction method is evaluated by the influence on spot target extraction accuracy. The experimental results indicate that using this flat-field correction method can decrease the non-uniform variance from 7.34 (LSB/10 bit) to 1.91 (LSB/10 bit) (improved by 74.1%) and reduce the noise effect on spot extraction accuracy, which improves it from 0.3453 pixel to 0.0116 pixel (1σ). The proposed approach solves the problem of non-uniform pixel response and improves imaging SNR for high-accuracy spot target localization.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/AO.58.004560DOI Listing
June 2019