48 results on '"Yifan Deng"'
Search Results
2. Deep Recurrent Reinforcement Learning for Intercept Guidance Law under Partial Observability
- Author
-
Xu Wang, Yifan Deng, Yuanli Cai, and Haonan Jiang
- Subjects
Electronic computers. Computer science ,QA75.5-76.95 ,Cybernetics ,Q300-390 - Abstract
Nowadays, the rapid development of hypersonic vehicles brings great challenges to the missile defense system. As achieving successful interception depends highly on terminal guidance laws, research on guidance laws for intercepting highly maneuvering targets has aroused increasing attention. Artificial intelligence technologies, such as deep reinforcement learning (DRL), have been widely applied to improve the performance of guidance laws. However, the existing DRL guidance laws rarely consider the partial observability problem of onboard sensors, resulting in the limitations of their engineering applications. In this paper, a deep recurrent reinforcement learning (DRRL)-based guidance method is investigated to address the intercept guidance problem against maneuvering targets under partial observability. The sequence consisting of previous state observations is utilized as the input of the policy network. A recurrent layer is introduced into the networks to extract hidden information behind the temporal sequence to support policy training. The guidance problem is formulated as a partially observable Markov decision process model, and then a range-weighted reward function that considers the line-of-sight rate and energy consumption is designed to guarantee convergence of policy training. The effectiveness of the proposed DRRL guidance law is validated by extensive numerical simulations.
- Published
- 2024
- Full Text
- View/download PDF
3. A real-time feeding behavior monitoring system for individual yak based on facial recognition model
- Author
-
Yuxiang Yang, Meiqi Liu, Zhaoyuan Peng, Yifan Deng, Luhui Gu, and Yingqi Peng
- Subjects
YOLO ,StrongSORT ,Individual feeding behavior ,Yak ,Yak face classification ,Electronic computers. Computer science ,QA75.5-76.95 - Abstract
Feeding behavior is known to affect the welfare and fattening efficiency of yaks in feedlots. With the advancement of machine vision and sensor technologies, the monitoring of animal behavior is progressively shifting from manual observation towards automated and stress-free methodologies. In this study, a real-time detection model for individual yak feeding and picking behavior was developed using YOLO series model and StrongSORT tracking model. In this study, we used videos collected from 11 yaks raised in two pens to train the yak face classification with YOLO series models and tracked their individual behavior using the StrongSORT tracking model. The yak behavior patterns detected in trough range were defined as feeding and picking, and the overall detection performance of these two behavior patterns was described using indicators such as accuracy, precision, recall, and F1-score. The improved YOLOv8 and Strongsort model achieved the best performance, with detection accuracy, precision, recall, and F1-score of 98.76%, 98.77%, 98.68%, and 98.72%, respectively. Yaks which have similar facial features have a chance of being confused with one another. A few yaks were misidentified because their faces were obscured by another yak’s head or staff. The results showed that individual yak feeding behaviors can be accurately detected in real-time using the YOLO series and StrongSORT models, and this approach has the potential to be used for longer-term yak feeding monitoring. In the future, a dataset of yaks in various cultivate environments, group sizes, and lighting conditions will be included. Furthermore, the relationship between feeding time and yak weight gain will be investigated in order to predict livestock weight.
- Published
- 2024
- Full Text
- View/download PDF
4. Stretchable liquid metal based biomedical devices
- Author
-
Yifan Deng, Fan Bu, Yujie Wang, Pei Song Chee, Xiangye Liu, and Cao Guan
- Subjects
Electronics ,TK7800-8360 ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Abstract Pursuit of improved living quality has stimulated great demand for high-performance conformal healthcare devices in modern human society. However, manufacturing of efficient, comfortable and stretchable biomedical apparatus faces huge challenges using traditional materials. Liquid metals (LMs) show remarkable potential to solve this problem due to their extraordinary biocompatibility, stretchability, thermal and electrical conductivity. In recent years, tremendous explorations have attempted to make stretchable biomedical devices with LMs. Herein, we review the stretchable LM-based biomedical devices on the topics of disease treatment and human function augmenting. The representative and up-to-date neural interfaces, alloy cement, e-vessels, soft heaters, exoskeletons, and e-skins are summarized. The existing issues of LMs applied for biomedical devices are also discussed. This review can provide guidance for the follow-up research in LM-based biomedical devices.
- Published
- 2024
- Full Text
- View/download PDF
5. An Effective Yak Behavior Classification Model with Improved YOLO-Pose Network Using Yak Skeleton Key Points Images
- Author
-
Yuxiang Yang, Yifan Deng, Jiazhou Li, Meiqi Liu, Yao Yao, Zhaoyuan Peng, Luhui Gu, and Yingqi Peng
- Subjects
improved YOLOv7-pose ,yak ,image processing ,deep learning ,Agriculture (General) ,S1-972 - Abstract
Yak behavior is a valuable indicator of their welfare and health. Information about important statuses, including fattening, reproductive health, and diseases, can be reflected and monitored through several indicative behavior patterns. In this study, an improved YOLOv7-pose model was developed to detect six yak behavior patterns in real time using labeled yak key-point images. The model was trained using labeled key-point image data of six behavior patterns including walking, feeding, standing, lying, mounting, and eliminative behaviors collected from seventeen 18-month-old yaks for two weeks. There were another four YOLOv7-pose series models trained as comparison methods for yak behavior pattern detection. The improved YOLOv7-pose model achieved the best detection performance with precision, recall, mAP0.5, and mAP0.5:0.95 of 89.9%, 87.7%, 90.4%, and 76.7%, respectively. The limitation of this study is that the YOLOv7-pose model detected behaviors under complex conditions, such as scene variation, subtle leg postures, and different light conditions, with relatively lower precision, which impacts its detection performance. Future developments in yak behavior pattern detection will amplify the simple size of the dataset and will utilize data streams like optical and video streams for real-time yak monitoring. Additionally, the model will be deployed on edge computing devices for large-scale agricultural applications.
- Published
- 2024
- Full Text
- View/download PDF
6. Astrocyte senescence-like response related to peripheral nerve injury-induced neuropathic pain
- Author
-
Jingyi Du, Nan Cheng, Yifan Deng, Ping Xiang, Jianfen Liang, Zhenye Zhang, Ziqing Hei, and Xiang Li
- Subjects
Neuropathic pain ,Peripheral nerve injury ,Neuroinflammation ,Senescence ,Astrocyte ,Cytology ,QH573-671 - Abstract
Abstract Background Peripheral nerve damage causes neuroinflammation, which plays a critical role in establishing and maintaining neuropathic pain (NeP). The mechanisms contributing to neuroinflammation remain poorly elucidated, and pharmacological strategies for NeP are limited. Thus, in this study, we planned to explore the possible link between astrocyte senescence and NeP disorders following chronic sciatic nerve injury. Methods An NeP animal model was established by inducing chronic constrictive injury (CCI) to the sciatic nerve in adult rats. A senolytic drug combination of dasatinib and quercetin was gavaged daily from the first postoperative day until the end of the study. Paw mechanical withdrawal threshold (PMWT) and paw thermal withdrawal latency (PTWL) were evaluated to assess behaviors in response to pain in the experimental rats. Senescence-associated β-galactosidase staining, western blot analysis, and immunofluorescence were applied to examine the levels of proinflammatory factors and severity of the senescence-like response in the spinal cord. Lipopolysaccharide (LPS) was administered to induce senescence of spinal astrocytes in primary cultures in vitro, to explore the potential impacts of senescence on the secretion of proinflammatory factors. Furthermore, single-cell RNA sequencing (scRNA-seq) was conducted to identify senescence-related molecular responses in spinal astrocytes under neuropathic pain. Results Following sciatic nerve CCI, rats exhibited reduced PMWT and PTWL, increased levels of spinal proinflammatory factors, and an enhanced degree of senescence in spinal astrocytes. Treatment with dasatinib and quercetin effectively attenuated spinal neuroinflammation and mitigated the hypersensitivities of the rats subjected to sciatic nerve CCI. Mechanistically, the dasatinib-quercetin combination reversed senescence in LPS-stimulated primary cultured astrocytes and decreased the levels of proinflammatory factors. The scRNA-seq data revealed four potential senescence-related genes in the spinal astrocyte population, and the expression of clusterin (CLU) protein was validated via in vitro experiments. Conclusion The findings indicate the potential role of astrocyte senescence in neuroinflammation following peripheral nerve injury, and suggest that targeting CLU activation in astrocytes might provide a novel therapeutic strategy to treat NeP. Graphical abstract
- Published
- 2023
- Full Text
- View/download PDF
7. Commentary: Case report: Chronic neutrophilic leukemia associated with monoclonal gammopathies. A case series and review of genetic characteristics and practical management
- Author
-
Yifan Deng, Shuai Han, Xiaohui Gao, Yang Liu, and Jiapei Gao
- Subjects
chronic neutrophilic leukemia ,monoclonal gammopathy of undetermined significance ,CSF3R ,gene mutations ,diagnosis ,pathogenesis ,Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Published
- 2024
- Full Text
- View/download PDF
8. Gut microbiota changes in animal models of spinal cord injury: a preclinical systematic review and meta-analysis
- Author
-
Zhenye Zhang, Nan Cheng, Jianfen Liang, Yifan Deng, Ping Xiang, Ziqing Hei, and Xiang Li
- Subjects
Gut microbiota ,spinal cord injury ,meta analysis ,Medicine - Abstract
AbstractBackground An increasing number of studies show that the intestinal flora is closely related to spinal cord injury. Many researchers are exploring the changes in the richness, diversity, and evenness of intestinal flora in spinal cord injury animal models to identify the characteristic bacteria.Methods A comprehensive literature search was conducted using three databases: PubMed, Embase, and Web of Science. A meta-analysis was performed using R 4.3.1 to evaluate the comparison of microbiota diversity, richness, and evenness and the relative abundance of intestinal microbiota in animals with spinal cord injury and blank controls.Results Fifteen studies were included in the meta-analysis, of which 12 involved gut microbiota distribution indicators and 11 included intestinal microflora relative abundance indicators. Meta-analysis of high-dimensional indicators describing the distribution of the gut microbiota identified a substantial decline in the evenness and richness of the intestinal flora. In addition, the Actinobacteria phylum and Erysipelotrichales and Clostridiales orders were significantly different between the spinal cord injury and sham groups; therefore, they may be the characteristic bacteria in spinal cord injury models.Conclusion Our meta-analysis suggested that the gut microbiota in the spinal cord injury animal model group was altered compared with that in the control group, with varying degrees of changes in richness and evenness and potentially pathogenic characteristic flora. More rigorous methodological studies are needed because of the high heterogeneity and limited sample size. Further research is needed to clinically apply intestinal microbiota and potentially guide fecal microbiota transplantation therapy.
- Published
- 2023
- Full Text
- View/download PDF
9. Modeling and Disturbance Analysis of Spinning Satellites with Inflatable Protective Structures
- Author
-
Yuting Shang, Yifan Deng, Yuanli Cai, Yu Chen, Sirui He, Xuanchong Liao, and Haonan Jiang
- Subjects
spinning satellite ,inflatable protective structure ,multi-body dynamic modeling ,spring hinge unfolding model ,spring expansion model ,disturbance analysis ,Motor vehicles. Aeronautics. Astronautics ,TL1-4050 - Abstract
The escalating proliferation of space debris poses an increasing risk to spinning satellites, elevating the probability of hazardous collisions that can result in severe damage or total loss of functionality. To address this concern, a pioneering inflatable protective structure is employed to ensure the optimal functionality of spinning satellites. Additionally, a multi-body dynamic modeling method based on spring hinge unfolding/spring expansion is proposed to tackle the complex dynamics of spinning satellites with inflatable protective structures during flight. This method enables analysis of the motion parameters of spinning satellites. First, the structural composition of a spinning satellite with inflatable protective structures is introduced and its flight process is analyzed. Then, an articulated spring hinge unfolding model or a spring expansion model using the Newton–Euler method is established to describe the unfolding or expansion of the spinning satellite with inflatable protective structures during flight. Finally, the effects on the motion parameters of a spinning satellite are analyzed through simulation under various working conditions.
- Published
- 2023
- Full Text
- View/download PDF
10. Electrochemical preparation of Al- Li alloy from Urea-LiCl molten salt at 353–393 K
- Author
-
Bingliang Gao, Zhiwei Liu, and Yifan Deng
- Subjects
lithium ,Al-Li alloy ,electrodeposition ,room-temperature molten salt ,urea ,Chemistry ,QD1-999 - Abstract
Al-Li alloy was prepared by electrodeposition on solid aluminum electrode in a urea-LiCl (77.5:22.5, mol%) molten salt system at 353–393 K. The results of cyclic voltammetry and chronopotentiometry show that underpotential deposition of Li occurs on the Al electrode and forms phases of Al(α) and AlLi(δ) which are confirmed by XRD measurements. Scanning electron microscopy observation of deposits indicates that Al-Li alloy with the thickness of 143 µm was obtained by potentiostatic electrolysis at −0.5 V vs. Li+/Li. The Li content in the alloy obtained at 373 K can reach 6.9 wt%. Galvanostatic electrolysis at 20 A demonstrated that Al-Li alloy coating on aluminum plate can be obtained from urea-LiCl electrolyte at 373 K in the atmosphere.
- Published
- 2023
- Full Text
- View/download PDF
11. A Novel Disturbance-Free-Payload Satellite Design for High-Precision Collaborative Observation
- Author
-
Yifan Deng, Jiaxing Zhou, Xiang Chen, Youxin Yao, and Qixuan Huang
- Subjects
disturbance-free payload ,collaborative observation ,vibration control ,multibody rigid-flexible dynamics ,Motor vehicles. Aeronautics. Astronautics ,TL1-4050 - Abstract
High-precision collaborative observation is urgently needed due to the increasing demands of space science missions. Based on a conventional DFP (disturbance-free-payload) configuration, this paper presents a novel DFP that has great potential to deal with collaborative observation missions. The novel DFP system is developed, in which two or more payloads are installed via a non-contact unit and installed parallel configuration. Thus, the novel design is a multibody dynamics system. With the incorporation of the dynamics of the flexible umbilical between the PMs (payload modules) and SM (support module), the six-degrees-of-freedom multibody rigid–flexible dynamics of the whole system are derived. To verify the effectiveness of the novel DFP design in a collaborative observation mission, a multi-loop controller is designed for an inertial Earth collaborative observation mission. Simulation studies are conducted, which indicate that the proposed design can complete collaborative observation and achieve high precision.
- Published
- 2023
- Full Text
- View/download PDF
12. A Fast Nonsingular Terminal Sliding Mode Control Method for Nonlinear Systems With Fixed-Time Stability Guarantees
- Author
-
Ye Tian, Yuanli Cai, and Yifan Deng
- Subjects
Fixed-time stability ,nonsingular terminal sliding mode control ,nonlinear system ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
This paper proposes a nonsingular terminal sliding mode control scheme with fast fixed-time convergence for a class of second-order nonlinear systems in the presence of matched uncertainties and perturbations. First, based on fixed-time stability theory, a novel stable system is proposed. Then, using the fixed-time stable system, a fast fixed-time nonsingular terminal sliding surface is derived. The settling time is independent of the initial system state and can be set in advance with the design parameters; the upper-bound of convergence time is derived from the Lyapunov theory. Moreover, the proposed control scheme has an advantage in convergence rate over existing results and achieves better control performance with low control energy cost. The simulation results for a tracking system with a single inverted pendulum are presented to validate the effectiveness and superiority of the proposed control method.
- Published
- 2020
- Full Text
- View/download PDF
13. Corrigendum: Research on Dynamic Equivalent SOC Estimation of Hybrid Energy Storage System Based on Sliding Mode Observer
- Author
-
Yifei Wang, Wei Jiang, Chengwei Zhu, Zhiqi Xu, and Yifan Deng
- Subjects
hybrid energy storage system ,sliding mode observer ,dynamic ESOC ,SOC estimation ,real-time charge balance ,General Works - Published
- 2022
- Full Text
- View/download PDF
14. Control of the Distributed Hybrid Energy Storage System Considering the Equivalent SOC
- Author
-
Wei Jiang, Zhiqi Xu, Bin Yu, Ke Sun, Kai Ren, Yifan Deng, and Saifur Rahman
- Subjects
consistency algorithm ,variable droop coefficient ,hybrid energy storage system ,state of charge ,hierarchical control structure ,General Works - Abstract
A hybrid energy storage system (HESS) consists of two or more types of energy storage components and the power electronics circuit to connect them. Therefore, the real-time capacity of this system highly depends on the state of the system and cannot be simply evaluated with traditional battery models. To tackle this challenge, an equivalent state of charge (ESOC) which reflects the remaining capacity of a HESS unit in a specific operation mode, is proposed in this paper. Furthermore, the proposed ESOC is applied to the control of the distributed HESS which contains several units with their own local targets. To optimally distribute the overall power target among these units, a sparse communication network-based hierarchical control framework is proposed. This framework considers the distributed control and optimal power distribution in the HESS from two aspects - the power output capability and the ESOC balance. Based on the primary droop control, the total power is allocated according to the maximum output capacity of each unit, and the secondary control is used to adjust the power from the perspective of ESOC balance. Therefore, each energy storage unit can be controlled to meet the local power demand of the microgrid. Simulation results based on MATLAB/Simulink verify the effectiveness of the application of the proposed equivalent SOC.
- Published
- 2021
- Full Text
- View/download PDF
15. Interferon-Induced Transmembrane Protein 3 Shapes an Inflamed Tumor Microenvironment and Identifies Immuno-Hot Tumors
- Author
-
Yun Cai, Wenfei Ji, Chuan Sun, Rui Xu, Xuechun Chen, Yifan Deng, Jiadong Pan, Jiayue Yang, Hongjun Zhu, and Jie Mei
- Subjects
IFITM3 ,tumor immunity ,pancancer ,bioinformatics analysis ,immunotherapy ,Immunologic diseases. Allergy ,RC581-607 - Abstract
Interferon-induced transmembrane protein 3 (IFITM3) is an interferon-induced membrane protein, which has been identified as a functional gene in multiple human cancers. The role of IFITM3 in cancer has been preliminarily summarized, but its relationship to antitumor immunity is still unclear. A pancancer analysis was conducted to investigate the expression pattern and immunological role of IFITM3 based on transcriptomic data downloaded from The Cancer Genome Atlas (TCGA) database. Next, correlations between IFITM3 and immunological features in the bladder cancer (BLCA) tumor microenvironment (TME) were assessed. In addition, the role of IFITM3 in estimating the clinical characteristics and the response to various therapies in BLCA was also evaluated. These results were next confirmed in the IMvigor210 cohort and a recruited cohort. In addition, correlations between IFITM3 and emerging immunobiomarkers, such as microbiota and N6-methyladenosine (m6A) genes, were assessed. IFITM3 was enhanced in most tumor tissues in comparison with adjacent tissues. IFITM3 was positively correlated with immunomodulators, tumor-infiltrating immune cells (TIICs), cancer immunity cycles, and inhibitory immune checkpoints. In addition, IFITM3 was associated with an inflamed phenotype and several established molecular subtypes. IFITM3 expression also predicted a notably higher response to chemotherapy, anti-EGFR therapy, and immunotherapy but a low response to anti-ERBB2, anti-ERBB4, and antiangiogenic therapy. In addition, IFITM3 was correlated with immune-related microbiota and m6A genes. In addition to BLCA, IFITM3 is expected to be a marker of high immunogenicity in most human cancers. In conclusion, IFITM3 expression can be used to identify immuno-hot tumors in most cancers, and IFITM3 may be a promising pancancer biomarker to estimate the immunological features of tumors.
- Published
- 2021
- Full Text
- View/download PDF
16. Research on Dynamic Equivalent SOC Estimation of Hybrid Energy Storage System Based on Sliding Mode Observer
- Author
-
Yifei Wang, Wei Jiang, Chengwei Zhu, Zhiqi Xu, and Yifan Deng
- Subjects
hybrid energy storage system ,sliding mode observer ,dynamic ESOC ,SOC estimation ,real-time charge balance ,General Works - Abstract
This article proposes a sliding mode observer based dynamic equivalent state of charge (ESOC) estimation method for hybrid energy storage system (HESS). Since different types of energy storage components and power electronics circuit are coupled in the HESS, the traditional SOC estimation method cannot reflect the real-time operation characteristics of the HESS. To tackle this problem, a sliding mode observer based on the model of the HESS is built in this article. By collecting the corresponding voltage and current signals, the internal parameters of energy storage elements can be observed accurately in real time. The dynamic ESOC is further defined with the idea of real-time charge balance to reflect the accurate available capacity of the HESS. Finally, the simulation results based on MATLAB/Simulink model are given to verify the feasibility of the proposed dynamic ESOC.
- Published
- 2021
- Full Text
- View/download PDF
17. Three-Dimensional Fast Fixed-time Convergence Guidance Law With Impact Angle Constraint
- Author
-
Ye Tian, Yuanli Cai, Zhenhua Yu, and Yifan Deng
- Subjects
Fixed-time convergence ,nonsingular terminal sliding mode control ,three-dimensional guidance ,maneuvering target ,impact angle ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
In this paper, a three-dimensional (3D) impact-angle-control guidance law is proposed based on the approaches of nonsingular terminal sliding mode control and fixed-time convergence theory to intercept a maneuvering target. The guidance law is derived based on the coupled 3D engagement dynamics. To intercept the target with an expected impact angle, the nonsingular terminal sliding mode control is designed to ensure that the line-of-sight (LOS) angles and rates rapidly reach the desired values. Furthermore, the fixed-time convergence algorithm is proposed to guarantee that the LOS angles and rates are convergent in fixed time. The upper bound of the settling time can be obtained by presetting the parameters of the proposed guidance law, and it is independent of the initial conditions. The stability of the guidance system is proven via Lyapunov stability theory. The simulation results are presented to validate the efficiency and superiority of the proposed guidance law.
- Published
- 2019
- Full Text
- View/download PDF
18. Modeling and Pointing Performance Analysis of Disturbance-Free-Payload System With Flexible Umbilical Connection
- Author
-
Jiaxing Zhou, Zhigang Wang, Wei Li, Lei Liu, Yifan Deng, and Qiang Zhao
- Subjects
Disturbance-Free-Payload ,vibration control ,pointing performance ,bead model ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 - Abstract
Disturbance-Free-Payload is a novel spacecraft architecture proposed to achieve perfect vibration isolation performance of space applications. In this paper, the object under study is a DFP system in which a flexible umbilical connection between the support module (SM) and the payload module (PM) is introduced for data, power and fluid transfer. Bead model accounting for properties of mass and flexibility, is utilized to model the flexible umbilical. With incorporation of bead model, six degree-of-freedom multibody rigid-flexible dynamics for the DFP system is established via Newtonian mechanics. Along with rotational coupling between solar panels and SM, translational coupling, in particular, is taken into consideration since there is a stringent requirement on relative position between PM and SM. Based on the accurate motion equations of the DFP system, simulation studies are conducted to gain insight of the impact of umbilical connection and translational coupling on pointing performance of the DFP system. Simulation results validate effectiveness of DFP configuration in isolating vibrations transmitted from SM to PM. Besides, umbilical connection plays an important part in degrading pointing performance of PM whereas it exerts little impact on SM. Moreover, translational coupling leads to significant pointing performance degradation for both PM and SM.
- Published
- 2019
- Full Text
- View/download PDF
19. Midcourse Iterative Guidance Method for the Impact Time and Angle Control of Two-Pulse Interceptors
- Author
-
Yifan Deng, Jinlei Ren, Xu Wang, and Yuanli Cai
- Subjects
impact angle and time control ,iterative guidance method ,midcourse guidance ,Motor vehicles. Aeronautics. Astronautics ,TL1-4050 - Abstract
To address the need for flexible energy management and impact angle control in the midcourse guidance of modern long-range antiballistic interceptors, an impact time and angle guidance law is designed for the exoatmospheric midcourse flight of antiballistic interceptors, which covers two pulse sections and two coast sections. The problem is described as an optimal control model with discontinuities in the system equations at interior points, and an iterative guidance method is used to efficiently solve the two-point boundary value problem. Simulation results demonstrate the effectiveness of the proposed guidance law; the obtained miss distance accuracy has an order of magnitude of 1 m, and the impact angle accuracy has a 1° order of magnitude while the angle can be achieved.
- Published
- 2022
- Full Text
- View/download PDF
20. Renal clear cell carcinoma metastasis to the breast ten years after nephrectomy: a case report and literature review
- Author
-
Yanjun Xu, Rui Hou, Qijie Lu, Yifan Deng, and Bin Hu
- Subjects
Renal cell carcinoma ,Neoplasm ,Metastasis ,Breast ,Mammography ,Ultrasonography ,Pathology ,RB1-214 - Abstract
Abstract Background Renal cell carcinoma most commonly metastasizes to the lungs, skeleton or liver. Metastatic renal cell carcinoma to the breast is very rare, especially for clear cell carcinoma, and few cases regarding this condition have been reported. Case Presentation The case we presented was a 68-year-old Chinese female with metastatic renal clear cell carcinoma of the left breast 10 years after a nephrectomy. Identification of the metastatic renal clear cell carcinoma in the breast required multiple breast imaging modalities. Imaging showed a single, ovary-shaped, well-defined hypo-echoic mass, with abundant blood flow on ultrasound images. The mass was enhanced early on MRI, and it was hypointense on a T1-weighted image and hyperintense on a fat-saturated T2-weighted image. Following surgical excision of the tumor, a routine immunohistochemistry antibody panel on the tumor cells revealed negative staining for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (Her-2). Strong positive staining for the cluster of differentiation 10 (CD10) and vimentin was present. Conclusion This case is unusual because of the site of metastatic progression. It is important for physicians to be aware of this progression so early diagnoses can be made, and appropriate therapeutic planning can be initiated.
- Published
- 2017
- Full Text
- View/download PDF
21. A Novel Viscosity-Temperature Model of Glass-Forming Liquids by Modifying the Eyring Viscosity Equation
- Author
-
Chunyu Chen, Huidan Zeng, Yifan Deng, Jingtao Yan, Yejia Jiang, Guorong Chen, Qun Zu, and Luyi Sun
- Subjects
viscosity model ,glass ,eyring equation ,glass transition temperature ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Many models have been created and attempted to describe the temperature-dependent viscosity of glass-forming liquids, which is the foundational feature to lay out the mechanism of obtaining desired glass properties. Most viscosity models were generated along with several impact factors. The complex compositions of commercial glasses raise challenges to settle these parameters. Usually, this issue will lead to unsatisfactory predicted results when fitted to a real viscosity profile. In fact, the introduction of the reliable viscosity-temperature data to viscosity equations is an effective approach to obtain the accurate parameters. In this paper, the Eyring viscosity equation, which is widely adopted for molecular and polymer liquids, was applied in this case to calculate the viscosity of glass materials. On the basis of the linear variation of molar volume with temperature during glass cooling, a modified temperature-dependent Eyring viscosity equation was derived with a distinguished mathematical expression. By means of combining high-temperature viscosity data and the glass transition temperature (Tg), nonlinear regression analysis was employed to obtain the accurate parameters of the equation. In addition, we have demonstrated that the different regression methods exert a great effect on the final prediction results. The viscosity of a series of glasses across a wide temperature range was accurately predicted via the optimal regression method, which was further used to verify the reliability of the modified Eyring equation.
- Published
- 2020
- Full Text
- View/download PDF
22. The Orbital Angular Momentum Modes Supporting Fibers Based on the Photonic Crystal Fiber Structure
- Author
-
Hu Zhang, Xiaoguang Zhang, Hui Li, Yifan Deng, Lixia Xi, Xianfeng Tang, and Wenbo Zhang
- Subjects
space division multiplexing ,mode division multiplexing ,fiber design and fabrication ,orbital angular momentum ,photonic crystal fibers ,Crystallography ,QD901-999 - Abstract
The orbital angular momentum (OAM) of light can be another physical dimension that we exploit to make multiplexing in the spatial domain. The design of the OAM mode supporting fiber attracts many attentions in the field of the space division multiplexing (SDM) system. This paper reviews the recent progresses in photonic crystal fiber (PCF) supporting OAM modes, and summarizes why a PCF structure can be used to support stable OAM transmission modes. The emphasis is on the circular PCFs, which possess many excellent features of transmission performance, such as good-quality OAM modes, enough separation of the effective indices, low confinement loss, flat dispersion, a large effective area, and a low nonlinear coefficient. We also compare the transmission properties between the circular PCF and the ring core fiber, as well as the properties between the OAM EDFA based on circular PCF and the OAM EDFA based on the ring core fiber. At last, the challenges and prospects of OAM fibers based on the PCF structure are also discussed.
- Published
- 2017
- Full Text
- View/download PDF
23. Safety and efficacy of minimal transcatheter aortic valve replacement: A systematic review and meta-analysis
- Author
-
Yifan, Deng, Zhen, Fang, Yue, Ma, Xun, Sun, Jiapei, Gao, Li, Zhu, and Jing, Zhang
- Published
- 2024
- Full Text
- View/download PDF
24. The impact of early in-hospital use of PCSK9 inhibitors on cardiovascular outcomes in acute coronary syndrome patients: A systematic review and meta-analysis
- Author
-
Yifan, Deng, Yue, Ma, Yubin, Zhang, Jiapei, Gao, Xun, Sun, Shenghu, He, Li, Zhu, and Jing, Zhang
- Published
- 2024
- Full Text
- View/download PDF
25. Therapeutic Effects of PEG-Modified Polyamide Amine Dendrimer for Cell Free DNA Adsorption in Temporomandibular Joint Osteoarthritis.
- Author
-
Yuzhuo Hei, Jingyi Du, Zhizhao Deng, Yifan Deng, Yu Guan, Jing Yang, Sufang Chen, Ziyi Zhang, Siqing Jiang, and Qingbin Zhang
- Published
- 2024
- Full Text
- View/download PDF
26. A Novel Disturbance-Free-Payload Satellite Design for High-Precision Collaborative Observation
- Author
-
Huang, Yifan Deng, Jiaxing Zhou, Xiang Chen, Youxin Yao, and Qixuan
- Subjects
disturbance-free payload ,collaborative observation ,vibration control ,multibody rigid-flexible dynamics - Abstract
High-precision collaborative observation is urgently needed due to the increasing demands of space science missions. Based on a conventional DFP (disturbance-free-payload) configuration, this paper presents a novel DFP that has great potential to deal with collaborative observation missions. The novel DFP system is developed, in which two or more payloads are installed via a non-contact unit and installed parallel configuration. Thus, the novel design is a multibody dynamics system. With the incorporation of the dynamics of the flexible umbilical between the PMs (payload modules) and SM (support module), the six-degrees-of-freedom multibody rigid–flexible dynamics of the whole system are derived. To verify the effectiveness of the novel DFP design in a collaborative observation mission, a multi-loop controller is designed for an inertial Earth collaborative observation mission. Simulation studies are conducted, which indicate that the proposed design can complete collaborative observation and achieve high precision.
- Published
- 2023
- Full Text
- View/download PDF
27. Bone marrow-derived mesenchymal stem cells attenuate complete Freund's adjuvant-induced inflammatory pain by inhibiting the expression of P2X3.
- Author
-
Yifan Deng, Dongdong Yuan, Zhizhao Deng, Jianfen Liang, Zhenye Zhang, Ziqing Hei, and Xiang Li
- Subjects
- *
MESENCHYMAL stem cells , *NUCLEOTIDE sequencing , *INFLAMMATORY mediators , *TREATMENT effectiveness , *PAIN management - Abstract
Bone marrow-derived mesenchymal stem cells (BMSCs) show a good property for pain treatment by modulating inflammatory response. However, the underlying therapeutic effect and related mechanism of BMSCs on inflammatory pain remain unclear. Therefore, we explored the function and potential mechanism of BMSCs performing in a complete Freund's adjuvant (CFA)-induced inflammatory pain model in this study. Here, BMSCs were injected into the CFA-treated rats, and we used behavioural tests to evaluate the changes in hypersensitivity. High-throughput sequencing was used to screen out the hub genes. Molecular biology experiments were performed to detect the level of P2X3 or inflammatory mediators in rats and observed the distribution of P2X3 in neural cells. Furthermore, the function of the P2X3 was explored via inhibitor and activator experiments. Finally, we found that BMSCs alleviated hyperalgesia and spinal levels of pro-inflammatory factors in CFA-treated rats. High-throughput sequencing showed that P2X3 and P2X7 were identified as hub genes, and only the expression level of P2X3 was significantly down-regulated after BMSCs treatment. Immunohistochemistry showed that P2X3 mainly colocalized with microglia and astrocytes. The levels of P2X3 and proinflammatory factors were all significantly reduced after BMSC injection. Moreover, similar attenuation was found in the CFA-treated rats after injecting the P2X3 inhibitor, and a P2X3 antagonist reversed the attenuation induced by the BMSCs. These findings suggest that BMSCs exerted a therapeutic effect on inflammatory pain by inhibiting the expression of P2X3 and the excessive production of inflammatory mediators was associated with an increased P2X3 level and BMSC therapy reverse these effects. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
28. FBLIM1 mRNA is a novel prognostic biomarker and is associated with immune infiltrates in glioma.
- Author
-
Yifan Deng, Kailiang Zeng, Diancheng Wu, Yunzhi Ling, Yu Tian, Yi Zheng, Shumin Fang, Xiaocong Jiang, Gang Zhu, and Yanyang Tu
- Abstract
Glioma is the most common primary brain tumor. Filamin-binding LIM protein 1 (FBLIM1) has been identified in multiple cancers and is suspected of playing a part in the development of tumors. However, the potential function of FBLIM1 mRNA in glioma has not been investigated. In this study, the clinical information and transcriptome data of glioma patients were, respectively, retrieved from the TCGA and CGGA databases. The expression level of FBLIM1 mRNA was shown to be aberrant in a wide variety of malignancies. Significantly, when glioma samples were compared to normal brain samples, FBLIM1 expression was shown to be significantly elevated in the former. A poor prognosis was related to high FBLIM1 expression, which was linked to more advanced clinical stages. Notably, multivariate analyses demonstrated that FBLIM1 expression was an independent predictor for the overall survival of glioma patients. Immune infiltration analysis disclosed that FBLIM1 expression had relevance with many immune cells. The results of RT-PCR suggested that FBLIM1 expression was markedly elevated in glioma specimens. Functional experiments unveiled that the knockdown of FBLIM1 mRNA suppressed glioma cell proliferation. In general, we initially discovered that FBLIM1 mRNA might be a possible prognostic marker in glioma. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
29. Modeling and Pointing Performance Analysis of Disturbance-Free-Payload System With Flexible Umbilical Connection
- Author
-
Zhi Gang Wang, Qiang Zhao, Lei Liu, Jiaxing Zhou, Yifan Deng, and Wei Li
- Subjects
Coupling ,Physics ,General Computer Science ,Spacecraft ,business.industry ,Disturbance-Free-Payload ,Payload (computing) ,vibration control ,General Engineering ,Equations of motion ,Power (physics) ,Vibration ,bead model ,Vibration isolation ,Control theory ,Position (vector) ,General Materials Science ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,pointing performance ,business ,lcsh:TK1-9971 - Abstract
Disturbance-Free-Payload is a novel spacecraft architecture proposed to achieve perfect vibration isolation performance of space applications. In this paper, the object under study is a DFP system in which a flexible umbilical connection between the support module (SM) and the payload module (PM) is introduced for data, power and fluid transfer. Bead model accounting for properties of mass and flexibility, is utilized to model the flexible umbilical. With incorporation of bead model, six degree-of-freedom multibody rigid-flexible dynamics for the DFP system is established via Newtonian mechanics. Along with rotational coupling between solar panels and SM, translational coupling, in particular, is taken into consideration since there is a stringent requirement on relative position between PM and SM. Based on the accurate motion equations of the DFP system, simulation studies are conducted to gain insight of the impact of umbilical connection and translational coupling on pointing performance of the DFP system. Simulation results validate effectiveness of DFP configuration in isolating vibrations transmitted from SM to PM. Besides, umbilical connection plays an important part in degrading pointing performance of PM whereas it exerts little impact on SM. Moreover, translational coupling leads to significant pointing performance degradation for both PM and SM.
- Published
- 2019
30. Three-Dimensional Fast Fixed-time Convergence Guidance Law With Impact Angle Constraint
- Author
-
Zhenhua Yu, Yifan Deng, Yuanli Cai, and Ye Tian
- Subjects
Lyapunov stability ,General Computer Science ,Settling time ,Computer science ,three-dimensional guidance ,General Engineering ,nonsingular terminal sliding mode control ,impact angle ,Stability (probability) ,Upper and lower bounds ,Constraint (information theory) ,Fixed-time convergence ,Law ,Convergence (routing) ,maneuvering target ,General Materials Science ,Symbolic convergence theory ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,Guidance system ,lcsh:TK1-9971 - Abstract
In this paper, a three-dimensional (3D) impact-angle-control guidance law is proposed based on the approaches of nonsingular terminal sliding mode control and fixed-time convergence theory to intercept a maneuvering target. The guidance law is derived based on the coupled 3D engagement dynamics. To intercept the target with an expected impact angle, the nonsingular terminal sliding mode control is designed to ensure that the line-of-sight (LOS) angles and rates rapidly reach the desired values. Furthermore, the fixed-time convergence algorithm is proposed to guarantee that the LOS angles and rates are convergent in fixed time. The upper bound of the settling time can be obtained by presetting the parameters of the proposed guidance law, and it is independent of the initial conditions. The stability of the guidance system is proven via Lyapunov stability theory. The simulation results are presented to validate the efficiency and superiority of the proposed guidance law.
- Published
- 2019
31. Evolution of the Anion Relay Chemistry: Construction of Architecturally Complex Natural Products
- Author
-
Yifan Deng and Amos B. Smith
- Subjects
Biological Products ,Bryostatin 1 ,010405 organic chemistry ,Chemistry ,Indolizidine ,Stereoisomerism ,General Medicine ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Combinatorial chemistry ,Coupling reaction ,Article ,0104 chemical sciences ,law.invention ,Arc (geometry) ,chemistry.chemical_compound ,Transfer agent ,Relay ,law ,Molecule ,Bifunctional - Abstract
Multi-component union tactics in which three or more fragments are rapidly assembled are highly prized in the construction of architecturally complex natural products. Anion Relay Chemistry (ARC), a multi-component union tactic, has just such potential to elaborate structurally diverse scaffolds in a single operation with excellent stereochemical control. Conceptually, the ARC tactic can be divided into two main classes: “Through-Bond”, by the relay of negative charge through the bonding system of a molecule; and “Through-Space”, by the migration of negative charge across space by a transfer agent. “Through-Space” Anion Relay Chemistry, the focus of this Account, can be further subdivided into two types: Type I ARC, originated from Tietze-Schaumann-Smith coupling reaction, which for the first time permits controllable Brook rearrangements to construct unsymmetrical adducts, and as such has been successfully employed in the total syntheses of diverse natural products, including the mycoticins, bryostatin 1, spongistatins, rimocidin, indolizidine alkaloids, and enigmazole A; and Type II ARC, central to which is the design of novel bifunctional linchpins that enable rapid assembly of linear and cyclic fragments with diverse architectural features, ranging from polyols, spiroketals and polyenes to polypropionate scaffolds. Recently, the Type II ARC tactic has been exploited as the key construction tactic in the total syntheses of the spirastrellolides, the cryptocarya acetates, secu’amamine A, mandelalide A and nahuoic acid C(i) (B(ii)). This Account will present the evolution of both the Type I and Type II Anion Relay tactics, in conjunction with some prominent applications. [Image: see text]
- Published
- 2020
32. Twistor-based synchronous sliding mode control of spacecraft attitude and position
- Author
-
Shuo Tang, Lei Liu, Qing Li, Yifan Deng, and Yanbin Zhao
- Subjects
020301 aerospace & aeronautics ,0209 industrial biotechnology ,Spacecraft ,business.industry ,Computer science ,Mechanical Engineering ,Mode (statistics) ,Aerospace Engineering ,TL1-4050 ,02 engineering and technology ,Sliding mode control ,Twistor theory ,020901 industrial engineering & automation ,0203 mechanical engineering ,Exponential stability ,Control theory ,Position (vector) ,business ,Control methods ,Motor vehicles. Aeronautics. Astronautics - Abstract
A synchronous control of relative attitude and position is required in separated ultra-quiet spacecraft, such as drag-free, disturbance-free, and distributed spacecraft. Thus, a twistor-based synchronous sliding mode control is investigated in this paper to solve the control problem of relative attitude and position among separated spacecraft modules. The twistor-based control design and the stability proof are implemented using the Modified Rodrigues Parameter (MRP). To evaluate the effectiveness of the proposed control method, this paper presents a case study of separated spacecraft flying control considering the mass uncertainty and external disturbances. In addition, a simulation study of the Proportional-Derivative (PD) control is also presented for comparison. The results indicate that the twistor-based sliding mode controller can ensure global asymptotic stability. The states converge fast with ultra-precision and ultra-stability in both the attitude and position. Moreover, the proposed twistor-based sliding mode control system is robust to the mass uncertainty and external disturbances. Keywords: Distributed spacecraft, Gravitational wave detection, Synchronous control, Ultra-precision, Ultra-stability
- Published
- 2018
33. Three-dimensional cooperative interception guidance law with impact time constraint.
- Author
-
Hongxia, Li, Yifan, Deng, and Cai, Yuanli
- Subjects
TIME ,FINITE, The ,ALGORITHMS ,ELECTRIC cooperatives - Abstract
This article proposes a new terminal cooperative guidance law with impact time constraint in three-dimensional (3D) engagement. Two parts are comprised by this guidance scheme to control the impact time and fulfill the interception. The guidance law along the line-of-sight (LOS) direction is first designed based on finite time consensus protocol to share time-to-go values among missiles and reach the consensus. Meanwhile, the guidance law on the LOS normal direction is developed based on the fast finite time control method to achieve the interception. The stability analysis of the proposed guidance law based on the Lyapunov theory is also demonstrated in detail. Moreover, the maneuvering target can be intercepted successfully under the presented control algorithm, and the guidance system can fulfill stability within finite time. Additionally, the effectiveness and applicability of the proposed guidance scheme are explicitly verified through simulation tests. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
34. Structural and Functional Characterization of 4‐Hydroxyphenylacetate 3‐Hydroxylase from Escherichia coli
- Author
-
Murielle Lombard, Olivier Back, Ludovic Pecqueur, Bruno Faivre, Yifan Deng, Marc Fontecave, Chaire Chimie des processus biologiques, Laboratoire de Chimie des Processus Biologiques (LCPB), and Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Hydroxybenzoic acid ,Protein Conformation ,010402 general chemistry ,Coumaric acid ,01 natural sciences ,Biochemistry ,Mixed Function Oxygenases ,Catalysis ,Hydroxylation ,chemistry.chemical_compound ,Phenols ,Oxidoreductase ,[CHIM.ANAL]Chemical Sciences/Analytical chemistry ,Escherichia coli ,Formate ,Molecular Biology ,Flavin adenine dinucleotide ,chemistry.chemical_classification ,Molecular Structure ,010405 organic chemistry ,Organic Chemistry ,Combinatorial chemistry ,0104 chemical sciences ,chemistry ,Molecular Medicine - Abstract
International audience; The hydroxylation of phenols into polyphenols, which are valuable chemicals and pharmaceutical products, is a challenging reaction. The search for green synthetic processes has led to considering microorganisms and pure hydroxylases as catalysts for phenol hydroxylation. Herein, we report the structural and functional characterization of the flavin adenine dinucleotide (FAD)‐dependent 4‐hydroxyphenylacetate 3‐monooxygenase from Escherichia coli, named HpaB. It is shown that this enzyme enjoys a relatively broad substrate specificity, which allows the conversion of a number of non‐natural phenolic compounds, such as tyrosol, hydroxymandelic acid, coumaric acid, hydroxybenzoic acid and its methyl ester, and phenol, into the corresponding catechols. The reaction can be performed by using a simple chemical assay based on formate as the electron donor and the organometallic complex [Rh(bpy)Cp*(H2O)]2+ (Cp*: 1,2,3,4,5‐pentamethylcyclopentadiene, bpy: 2,2′‐bipyridyl) as the catalyst for FAD reduction. The availability of a crystal structure of HpaB in complex with FAD at 1.8 Å resolution opens up the possibility of the rational tuning of the substrate specificity and activity of this interesting class of phenol hydroxylases.
- Published
- 2019
- Full Text
- View/download PDF
35. Generation of Dithianyl and Dioxolanyl Radicals Using Photoredox Catalysis: Application in the Total Synthesis of the Danshenspiroketallactones via Radical Relay Chemistry
- Author
-
Amos B. Smith, Yifan Deng, K. N. Houk, Yike Zou, and Minh D. Nguyen
- Subjects
Light ,Polymers ,Radical ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Article ,Catalysis ,law.invention ,Turn (biochemistry) ,Polyol ,Relay ,law ,Physical and Theoretical Chemistry ,chemistry.chemical_classification ,Molecular Structure ,010405 organic chemistry ,Chemistry ,Organic Chemistry ,Photoredox catalysis ,Total synthesis ,Hydrogen atom ,Photochemical Processes ,Combinatorial chemistry ,0104 chemical sciences ,Chemical Sciences ,Surface modification ,Hydrogen - Abstract
Visible-light-induced generation of dithianyl and dioxolanyl radicals via selective hydrogen atom transfer (HAT) has been achieved. This radical relay tactic enables remote C(sp(3))—H functionalization to permit rapid access to polyol and spiroketal segments, and in turn has been exploited as a key synthetic construct in the total synthesis of the danshenspiroketallactones. The conformational stability of the danshenspiroketallactones has also been defined via experiments and DFT calculations.
- Published
- 2019
36. Renal clear cell carcinoma metastasis to the breast ten years after nephrectomy: a case report and literature review
- Author
-
Rui Hou, Yifan Deng, Bin Hu, Yanjun Xu, and Qijie Lu
- Subjects
Pathology ,medicine.medical_specialty ,Histology ,Breast imaging ,medicine.medical_treatment ,Estrogen receptor ,Vimentin ,Case Report ,Breast Neoplasms ,Nephrectomy ,030218 nuclear medicine & medical imaging ,Pathology and Forensic Medicine ,Metastasis ,03 medical and health sciences ,0302 clinical medicine ,Renal cell carcinoma ,lcsh:Pathology ,Medicine ,Humans ,Breast ,Neoplasm Metastasis ,Carcinoma, Renal Cell ,Ultrasonography ,Aged ,biology ,Cluster of differentiation ,business.industry ,Neoplasms, Second Primary ,General Medicine ,medicine.disease ,Kidney Neoplasms ,030220 oncology & carcinogenesis ,Clear cell carcinoma ,biology.protein ,Neoplasm ,Female ,business ,lcsh:RB1-214 ,Mammography - Abstract
Background Renal cell carcinoma most commonly metastasizes to the lungs, skeleton or liver. Metastatic renal cell carcinoma to the breast is very rare, especially for clear cell carcinoma, and few cases regarding this condition have been reported. Case Presentation The case we presented was a 68-year-old Chinese female with metastatic renal clear cell carcinoma of the left breast 10 years after a nephrectomy. Identification of the metastatic renal clear cell carcinoma in the breast required multiple breast imaging modalities. Imaging showed a single, ovary-shaped, well-defined hypo-echoic mass, with abundant blood flow on ultrasound images. The mass was enhanced early on MRI, and it was hypointense on a T1-weighted image and hyperintense on a fat-saturated T2-weighted image. Following surgical excision of the tumor, a routine immunohistochemistry antibody panel on the tumor cells revealed negative staining for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (Her-2). Strong positive staining for the cluster of differentiation 10 (CD10) and vimentin was present. Conclusion This case is unusual because of the site of metastatic progression. It is important for physicians to be aware of this progression so early diagnoses can be made, and appropriate therapeutic planning can be initiated.
- Published
- 2017
37. Oxidative [1,2]-Brook Rearrangements Exploiting Single-Electron Transfer: Photoredox-Catalyzed Alkylations and Arylations
- Author
-
Amos B. Smith, Qi Liu, and Yifan Deng
- Subjects
Alkylation ,Stereochemistry ,Oxidative phosphorylation ,010402 general chemistry ,Photochemistry ,01 natural sciences ,Biochemistry ,Hydrocarbons, Aromatic ,Article ,Catalysis ,Electron Transport ,Single electron ,Colloid and Surface Chemistry ,Molecule ,Organosilicon Compounds ,Molecular Structure ,010405 organic chemistry ,Chemistry ,Hypervalent molecule ,Oxidation reduction ,General Chemistry ,Photochemical Processes ,Electron transport chain ,0104 chemical sciences ,Oxidation-Reduction - Abstract
Oxidative [1,2]-Brook rearrangements via hypervalent silicon intermediates induced by photoredox-catalyzed single-electron transfer have been achieved, permitting the formation of reactive radical species that can engage in alkylations and arylations.
- Published
- 2017
38. Factors Controlling Reactivity in the Hydrogen Atom Transfer and Radical Addition Steps of a Radical Relay Cascade.
- Author
-
Yike Zou, Xiao-Song Xue, Yifan Deng, Smith III, Amos B., and Houk, K. N.
- Published
- 2019
- Full Text
- View/download PDF
39. Generation of Dithianyl and Dioxolanyl Radicals Using Photoredox Catalysis: Application in the Total Synthesis of the Danshenspiro-ketallactones via Radical Relay Chemistry.
- Author
-
Yifan Deng, Nguyen, Minh D., Yike Zou, Houk, K. N., and Smith III, Amos B.
- Published
- 2019
- Full Text
- View/download PDF
40. Total Synthesis of (-)-Nahuoic Acid Ci (Bii).
- Author
-
Qi Liu, Yifan Deng, and Smith, III, Amos B.
- Subjects
- *
POLYKETIDES , *METHYLTRANSFERASES , *HYDROGENATION , *METHOXYMETHYL compounds , *RING formation (Chemistry) - Abstract
A convergent total synthesis of (-)-nahuoic acid Ci(Bii) (3), a novel cis-decalin polyketide, has been achieved. Key synthetic transformations include Type II Anion Relay Chemistry (ARC) to construct the polyol chain, a Ti-catalyzed asymmetric Diels-Alder reaction to generate the cis-decalin skeleton, and a late-stage large fragment union exploiting a Micalizio alkoxide-directed alkyne-alkene coupling tactic. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
41. Total Synthesis of (-)-Nahuoic Acid Ci (Bii).
- Author
-
Qi Liu, Yifan Deng, and Smith, III, Amos B.
- Published
- 2017
- Full Text
- View/download PDF
42. Erbium-doped amplification in circular photonic crystal fiber supporting orbital angular momentum modes.
- Author
-
Yifan Deng, Hu Zhang, Hui Li, Xianfeng Tang, Lixia Xi, Wenbo Zhang, and Xiaoguang Zhang
- Published
- 2017
- Full Text
- View/download PDF
43. Diverse Pathways in Catalytic Reactions of Propargyl Aryldiazoacetates: Selectivity between Three Reaction Sites.
- Author
-
Huang Qiu, Yifan Deng, Marichev, Kostiantyn O., and Doyle, Michael P.
- Abstract
Three catalyst-dependent divergent reaction pathways for reactions of propargyl aryldiazoacetates are disclosed. Transition metal catalysts including those of rhodium(II), palladium(0 and II), silver(I), mercury(II), copper(I and II), platinum(II), and cationic gold(I) are effective for reactions that proceed through dinitrogen extrusion, carbene/alkyne metathesis, and aromatic substitution to form fused indeno-furanones, and use of tetrakis(acetonitrile)copper(I) provides indeno-furanones in the highest product yields. A Lewis acid catalyzed pathway that forms furan-2-ones is uncovered with FeCl3, ZnBr2, and BF3·Et2O as catalysts that proceed through activation of the aryldiazoacetate ester for arylpropargyl cation dissociation followed by recombination through cation addition to the diazo carbon. Neutral gold catalysts selectively activate the triple bond of propargyl aryldiazoacetates, resulting in the formation of allenic aryldiazoesters that further undergo uncatalyzed rearrangement. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
44. Unscented Kalman Filter for Spacecraft Pose Estimation Using Twistors.
- Author
-
Yifan Deng, Zhigang Wang, and Lei Liu
- Subjects
KALMAN filtering ,SPACE vehicles ,TWISTOR theory ,ROTATIONAL motion ,QUATERNIONS - Abstract
This study presents a new method to solve the pose estimation problem of the combined spacecraft translational and rotational motion using twistors. The twistor representation enables the use of the unscented Kalman filter in the proposed pose estimation method to achieve a higher estimation accuracy than can be achieved with the method using a dual-quaternion-based extended Kalman filter. The unscented Kalman fdter is difficult to design using dual quaternions because of the normalization constraint problem. To overcome this problem, the twistor representation in the framework of dual numbers is introduced to describe the spacecraft local pose error, whereas dual quaternions are used to describe the absolute pose. The unscented Kalman filter schemes, each of which uses different measurements, are designed based on the twistor representation. The proposed unscented Kalman filter schemes using twistors are compared with the dual-quaternion-bascd multiplicative extended Kalman filter through simulations. The results demonstrate the effectiveness of the proposed method and indicate that the twistor-based unscented Kalman filter is superior to the dual-quaternion-based multiplicative extended Kalman filter when both the initial estimation errors are large and the observation model is highly nonlinear. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
45. Modeling and Control for Spacecraft Relative Pose Motion by Using Twistor Representation.
- Author
-
Yifan Deng and Zhigang Wang
- Subjects
PROPORTIONAL navigation ,QUATERNIONS ,PROGRAMMABLE controllers ,LOGARITHMS ,NONLINEAR analysis - Abstract
The article presents studies on controller development work as conducted in dual quaternions. A study established a model-independent proportional derivative (PD)-like controller and a coupled relative motion model with the use of dual quaternions aimed with the use of feedback of logarithm of dual quaternion. Another study proposed an attitude tracking controller and a nonlinear adaptive position.
- Published
- 2016
- Full Text
- View/download PDF
46. Effect of Blanching Pretreatment before Drying on the Microstructure and Texture Quality of Dried Apple Slices
- Author
-
WANG Dong, ZHAO Yifan, DENG Zhining, SUN Haoyuan, WANG Yong, YUAN Yuejin
- Subjects
apple slices ,blanching ,microstructure parameters ,rehydration ratio ,macro-micro relationship ,Food processing and manufacture ,TP368-456 - Abstract
To improve the drying efficiency and quality of hot air-dried apple slices with blanching pretreatment, this study systematically evaluated the effects of two blanching pretreatments, hot water blanching and vacuum steam pulsed blanching, on the macroscopic drying performance of apple slices. The results indicated that under the conditions of 0.07 MPa vacuum, two blanching cycles, and blanching time of 3 minutes, vacuum steam pulsed blanching significantly enhanced the rehydration rate and textural quality of apple slices while reducing the drying time. Paraffin sectioning, microscopic observation and image processing were used to compare the microstructural changes of apple slices in terms of cell cross-sectional area, perimeter, equivalent diameter, cell roundness, wall roughness factor, and porosity under different branching conditions (temperature and time for hot water blanching; vacuum level, number of cycles, and time for vacuum steam pulsed blanching). The results showed that with the increase in temperature, blanching time and number of blanching cycles, apple cells exhibited changes that accelerated water evaporation during subsequent drying, thus shortening the drying time. Additionally, the relationship between microstructural parameters and rehydration ratio was fitted to a polynomial regression model. The findings of this study provide a theoretical basis for understanding the mechanisms by which vacuum steam pulsed blanching affects the microstructure and quality of dried apple slices.
- Published
- 2024
- Full Text
- View/download PDF
47. Ridge regression for predicting elastic moduli and hardness of calcium aluminosilicate glasses.
- Author
-
Yifan Deng, Huidan Zeng, Yejia Jiang, Guorong Chen, Jianding Chen, and Luyi Sun
- Published
- 2018
- Full Text
- View/download PDF
48. Construction of a Nomogram Prediction Model for Prognosis in Patients with Large Artery Occlusion-Acute Ischemic Stroke.
- Author
-
Haiyong, Zeng, Wencai, Li, Yunxiang, Zhou, Shaohuai, Xia, Kailiang, Zeng, Ke, Xu, Wenjie, Qiu, Gang, Zhu, Jiansheng, Chen, Yifan, Deng, Zhongzong, Qin, Huanpeng, Li, and Honghai, Luo
- Subjects
- *
ISCHEMIC stroke , *CEREBRAL infarction , *NOMOGRAPHY (Mathematics) , *RECEIVER operating characteristic curves , *PREDICTION models , *NEUTROPHIL lymphocyte ratio - Abstract
Patients with large artery occlusion-acute ischemic stroke (LAO-AIS) can experience adverse outcomes, such as brain herniation due to complications. This study aimed to construct a nomogram prediction model for prognosis in patients with LAO-AIS in order to maximize the benefits for clinical patients. Retrospective analysis of 243 patients with LAO-AIS from January 2019 to January 2022 with medical history data and blood examination at admission. Univariate and multivariate analyses were conducted through binary logistic regression equation analysis, and a nomogram prediction model was constructed. Results of this study showed that hyperlipidemia (odds ratio [OR] = 2.849, 95% confidence interval [CI] = 1.100–7.375, P = 0.031), right cerebral infarction (OR = 2.144, 95% CI = 1.106–4.156, P = 0.024), D-Dimer>500 ng/mL (OR = 2.891, 95% CI = 1.398–5.980, P = 0.004), and neutrophil-lymphocyte ratio >7.8 (OR = 2.149, 95% CI = 1.093–4.225, P = 0.027) were independent risk factors for poor early prognosis in patients with LAO-AIS. In addition, hypertension (OR = 1.947, 95% CI = 1.114–3.405, P = 0.019), hyperlipidemia (OR = 2.594, 95% CI = 1.281–5.252, P = 0.008), smoking (OR = 2.414, 95% CI = 1.368–4.261, P = 0.002), D-dimer>500 ng/mL (OR = 3.170, 95% CI = 1.533–6.553, P = 0.002), and neutrophil-lymphocyte ratio >7.8 (OR = 2.144, 95% CI = 1.231–3.735, P = 0.007) were independent risk factors for poor long-term prognosis. The early prognosis nomogram receiver operating characteristic curve area under the curve value was 0.688 for the training set and 0.805 for the validation set, which was highly differentiated. The mean error was 0.025 for the training set calibration curve and 0.016 for the validation set calibration curve. Both the training and validation set decision curve analyses indicated that the clinical benefit of the nomogram was significant. The long-term prognosis nomogram receiver operating characteristic curve area under the curve values was 0.697 for the training set and 0.735 for the validation set, showing high differentiation. The mean error was 0.041 for the training set calibration curve and 0.021 for the validation set calibration curve. Both of the training and validation set decision curve analyses demonstrated a substantial clinical benefit of the nomogram. The nomogram prediction model based on admission history data and blood examination are easy-to-use tools that provide an accurate individualized prediction for patients with LAO-AIS and can assist in early clinical decisions and in obtaining an early prognosis. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.