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Search Results: 1 - 10 of 41070 matches for " Yi Ren "
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Peroxisome Proliferator-Activator Receptor : A Link between Macrophage CD36 and Inflammation in Malaria Infection
Yi Ren
PPAR Research , 2012, DOI: 10.1155/2012/640769
Abstract: Severe malaria infection caused by Plasmodium falciparum is a global life-threatening disease and a leading cause of death worldwide. Intensive investigations have demonstrated that macrophages play crucial roles in control of inflammatory and immune responses and clearance of Plasmodium-falciparum-parasitized erythrocytes (PE). This paper focuses on how macrophage CD36 recognizes and internalizes PE and participates the inflammatory signaling in response to Plasmodium falciparum. In addition, recent advances in our current understanding of the biological actions of PPARγ on CD36 and malaria clearance from the hosts are highlighted. 1. Introduction Macrophages play a crucial role in the innate immunity [1] and are essential components of defense against the malaria infection. Macrophages can take up nonopsonic or opsonic Plasmodium-falciparum-parasitized erythrocytes (PE) by using CD36 and Fc receptors, respectively. Nonopsonic PE phagocytosis by macrophage CD36 plays a major role for PE clearance especially in the acute phase of primary malaria infection or nonimmune hosts [2, 3]. Therefore, upregulation of CD36 on macrophages could greatly trigger the capacity to clear parasites during acute malaria infection and thus is likely to be effective treatment for malaria infection. The intensive investigations demonstrate that peroxisome proliferator-activator receptor γ (PPARγ) plays an important role in the immune response via inhibiting the expression of inflammatory cytokines and control macrophage alternative activation [4–6] and has potential as a novel anti-inflammatory target for many inflammatory diseases [7] including parasitic infection [8–10]. CD36 can be induced by PPARγ ligands, and activation of PPARγ enhances the clearance of PE and inhibits the proinflammatory response [6, 11]. Here, we highlight recent advances in our current understanding of the biological actions of PPARγ on CD36 and malaria clearance from the hosts. 2. CD36 and Malaria Clearance Macrophages play a crucial role in innate immunity to malaria infection because they can phagocytose infected erythrocytes that limit the malaria density in the absence of cytophilic or opsonizing malaria-specific antibody [2]. Macrophage pattern-recognition receptors (PRRs), including Toll-like receptors (TLRs) and scavenger receptors such as CD36, are important components in the regulation of immune and inflammatory responses [12]. PRRs are a class of innate immune response-expressed proteins that recognize a wide range of molecules known as pathogen-associated molecular patterns (PAMPs)
Managing Inflammation after Spinal Cord Injury through Manipulation of Macrophage Function
Yi Ren,Wise Young
Neural Plasticity , 2013, DOI: 10.1155/2013/945034
Abstract: Spinal cord injury (SCI) triggers inflammation with activation of innate immune responses that contribute to secondary injury including oligodendrocyte apoptosis, demyelination, axonal degeneration, and neuronal death. Macrophage activation, accumulation, and persistent inflammation occur in SCI. Macrophages are heterogeneous cells with extensive functional plasticity and have the capacity to switch phenotypes by factors present in the inflammatory microenvironment of the injured spinal cord. This review will discuss the role of different polarized macrophages and the potential effect of macrophage-based therapies for SCI. 1. Introduction A large body of studies on rodents, primates, and humans has revealed that spinal cord injury (SCI) provokes an inflammatory response that causes further tissue damage and neurodegeneration [1]. Macrophages accumulate within the epicenter of the injured spinal cord and orchestrate this inflammatory response. Recent work indicates that macrophages display great plasticity and can alter their phenotypes and functions according to changes in the microenvironment. Understanding the mechanisms that promote anti-inflammatory properties of macrophages and control phenotype plasticity suggests novel therapeutic strategies for treating SCI and other related conditions. Several macrophage subsets with distinct functions have been reported, including M1 (classical activation), M2 (alternative activation), regulatory macrophages, tumor associated macrophages (TAM), and myeloid-derived suppressor cells (MDSC), and so forth [2]. Th1 cytokines and LPS-induced STAT1 signaling activate macrophages to express the classical M1 phenotype. M1 macrophages produce proinflammatory cytokines (TNF-α, IL-1), reactive oxygen species (ROS), and NO, contributing to tissue inflammation and damage. By contrast, M2 macrophages induced by Th2 cytokines produce anti-inflammatory factors (IL-10, TGF-β) and have a reduced capacity to produce proinflammatory molecules, thereby contributing to wound healing and tissue-remodeling. M2 macrophages can be separated into at least three different subgroups based on the type of stimulation and the subsequent expression of surface molecules and cytokines. IL-4 and IL-13 lead to M2a macrophages, immune complexes, and agonists of toll-like receptors (TLRs) which drive the M2b subtype, while IL-10, TGFβ, or glucocorticoids induce M2c macrophages [3]. Compared to M2 macrophages, M1 macrophages produced high levels of IL-1β, IL-6, IL-12, IL-23, CCL5, TNF-α, IFN-γ, and iNOS [4, 5], which have deleterious effects in SCI
Diversity of Cultivable Actinomycetes in Tropical Rainy Forest of Xishuangbanna, China  [PDF]
Yi Jiang, Xiu Chen, Yanru Cao, Zhen Ren
Open Journal of Soil Science (OJSS) , 2013, DOI: 10.4236/ojss.2013.31002

In order to obtain much more un-known actinomycetes for discovering new drug lead, one hundred soil samples were collected from five national natural protection areas of tropical rain forests, Mengla, Menglun, Mandian, Xiaomengyang and Guanping, in Xishuangbanna, Yunnan, China. 1652 purified cultures of actinobacteria were isolated from these samples by using 5 media. The 16S rRNA gene sequences of 388 selected strains were analyzed, and the phylogenetic analysis was carried out. 35 genera which belong to 8 orders and 14 families of the Class actinobacteria were identified. It is showed from research results that actinomycete diversity in tropical rain forest of Xishuangbanna is the highest comparing with all areas studied in our laboratories before. Selective isolation methods for un-known actinomycetes from soil samples, including medium and inhibitors are discussed in this paper.

Adaptive Rate Control for Multi-Antenna Multicast in OFDM Systems  [PDF]
Qinghe Du, Pinyi Ren, Yi Jia, Zhigang Chen
Communications and Network (CN) , 2013, DOI: 10.4236/cn.2013.53B2029
Abstract: We propose two rate control schemes for multi-antenna multicast in OFDM systems, which aim to maximize the minimum average rate over all users in a multicast group. In our system, we do not require all multicast users to successfully recover the signals received on each subcarrier. In contrast, we allow certain loss for multicast users, such that the multicast transmission rate can be increased. We assume that the loss-repairing can be completed at upper protocol layers via advanced fountain codes. Following this principle, we formulate the rate control problem via beamforming in multi-antenna multicast to optimize the minimum achievable rate for all multicast users. While the computation complexity to solve for the optimal beamformer is prohibitively high, we propose a suboptimal iterative rate control scheme. Moreover, we modify the above optimization problem by selecting a ?xed proportion of users on each subcarrier. The beamformer searching process will then be performed only based on the selected users on each subcarrier, such that the complexity can be further reduced. We also solve this new problem with a low complexity approach. Theoretical analyses and simulation results show that our proposed two rate control schemes can have higher minimum average rate than the baseline scheme without rate control, while achieving low complexity.
Effect of Spinning Magnetic Ferrite on the Exclusion Zone  [PDF]
Yi Zhou, Xing Wen, Alexandr A. Shpilman, Quansheng Ren
Journal of Biosciences and Medicines (JBM) , 2017, DOI: 10.4236/jbm.2017.512001
Colloidal and molecular solutes in suspension are excluded from the vicinity of various hydrophilic surfaces, leaving an exclusion zone (EZ) of hundreds of micrometers. Such exclusion zones were observed in the vicinity of many types of surface including artificial and natural hydrogels, biological tissues as well as hydrophilic polymers. Old studies have shown that the near-surface exclusion zone expands extensively in the presence of incident radiant energy, especially the infrared light. Developments of electromagnetic biology and quantum biology indicate that electron and nuclear spin may have a direct impact on the biological process. Inspired by these researches, the effects of spinning magnetic ferrite on EZ were studied. It is shown that spinning magnetic ferrite profoundly expands these zones in an irreversible manner.
Perturbation-Based Schemes with Ultra-Lightweight Computation to Protect User Privacy in Smart Grid
Wei Ren,Liangli Ma,Yi Ren
International Journal of Distributed Sensor Networks , 2013, DOI: 10.1155/2013/230140
Network Coding based Dependable and Efficient Data Survival in Unattended Wireless Sensor Networks
Wei Ren,Junge Zhao,Yi Ren
Journal of Communications , 2009, DOI: 10.4304/jcm.4.11.894-901
Abstract: In Unattended Wireless Sensor Networks( UWSNs), sensed data are stored locally for a long term till to collector’s retrieval. It is motivated by the scenarios where only historical information or digest data, not real-time data, are of interest. Such paradigm indeed has been attracted more and more interests in research communities recently. Data storage in UWSNs should be dependable to defend random failure or node compromise, as well as the efficiency of communication and storage should be maintained. In this paper, we propose a dependable and efficient data survival scheme to maximize the data survival degree upon data retrieval. Our scheme makes use of computational secret sharing to achieve fault tolerance and compromise resilience, and takes advantages of network coding to further improve communication efficiency. As justified by our extensive analysis, the proposed scheme has the most advantages in terms of robustness and lightweight.
Survey on Anonymity in Unstructured Peer-to-Peer Systems
Ren-Yi Xiao,

计算机科学技术学报 , 2008,
Abstract: Although anonymizing Peer-to-Peer (P2P) networks often means extra cost in terms of transfer efficiency,many systems try to mask the identities of their users for privacy consideration.By comparison and analysis of existing approaches, we investigate the properties of unstructured P2P anonymity,and summarize current attack models on these designs.Most of these approaches are path-based,which require peers to pre-construct anonymous paths before transmission,thus suffering significant overhead and poor reliability.We also discuss the open problems in this field and propose several future research directions.
Maneuvering Target Doppler-Bearing Tracking with Signal Time Delay Using Interacting Multiple Model Algorithms
Suzhi Bi;Xiao Yi Ren
PIER , 2008, DOI: 10.2528/PIER08091501
Abstract: For maneuvering target Doppler-bearing tracking with signal time delay, a novel approach called ISE-IMM is proposed in this paper. The iterative state estimation (ISE) method is designed to eliminate the negative influence of time delay effect and an interacting multiple model (IMM) filter is embedded to estimate the state according to the measurements of the delayed signal. The nonlinear filter preferred in this paper is a particle filter (PF) with an improved resampling procedure. Performance of our proposed method is evaluated in Monte Carlo simulations. Results show the effectiveness and stability of ISE-IMM-PF in combating the negative effect of signal time delay.
BVS: A Lightweight Forward and Backward Secure Scheme for PMU Communications in Smart Grid
Wei Ren,Jun Song,Min Lei,Yi Ren
International Journal of Digital Multimedia Broadcasting , 2011, DOI: 10.1155/2011/382147
Abstract: In smart grid, phaser measurement units (PMUs) can upload readings to utility centers via supervisory control and data acquisition (SCADA) or energy management system (EMS) to enable intelligent controlling and scheduling. It is critical to maintain the secrecy of readings so as to protect customers' privacy, together with integrity and source authentication for the reliability and stability of power scheduling. In particular, appealing security scheme needs to perform well in PMUs that usually have computational resource constraints, thus designed security protocols have to remain lightweight in terms of computation and storage. In this paper, we propose a family of schemes to solve this problem. They are public key based scheme (PKS), password based scheme (PWS) and billed value-based scheme (BVS). BVS can achieve forward and backward security and only relies on hash functions. Security analysis justifies that the proposed schemes, especially BVS, can attain the security goals with low computation and storage cost. 1. Introduction Smart grid is envisioned as a long-term strategy for national energy independence, controlling emission, and combating global warming [1]. Smart grid technologies utilize intelligent transmission to deliver electricity, together with distribution networks to enable two-way communications. These approaches aim to improve reliability and efficiency of the electric system via gathering consumption data, delivering dynamic optimization of operations, and arranging energy saving schedules. The smart grid promises to transform traditional centralized, producer-controlled network to a decentralized, consumer-interactive network. For example, consumers react to pricing signals delivered by control unit from smart meters to achieve active load adjustment. Supervisory control And data acquisition (SCADA) or energy management system (EMS) may collect one data points every 1 to 2?seconds, whereas phaser measurement units (PMUs) may collect 30 to 60?data points per second [2]. The security of smart grid is a critical issue for its applicability, development and deployment [3–7]. On one hand, the security, and especially the availability of power supplying system, affects homeland security, as it is an indispensable infrastructure for pubic living system [8–10]. That is, any transient interruption will result in economic and social disaster. On the other hand, introduction of end devices such as PMUs requests for data and communication security to support secure and reliable uploading of measurements [11, 12]. As the PMUs are exposed far
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