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Search Results: 1 - 10 of 78257 matches for " Yitao Chen "
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An efficient certificateless authenticated key agreement protocol without bilinear pairings
Debiao He,Yitao Chen
Computer Science , 2011, DOI: 10.1016/j.mcm.2011.08.004
Abstract: Certificateless public key cryptography simplifies the complex certificate management in the traditional public key cryptography and resolves the key escrow problem in identity-based cryptography. Many certificateless authenticated key agreement protocols using bilinear pairings have been proposed. But the relative computation cost of the pairing is approximately twenty times higher than that of the scalar multiplication over elliptic curve group. Recently, several certificateless authenticated key agreement protocols without pairings were proposed to improve the performance. In this paper, we propose a new certificateless authenticated key agreement protocol without pairing. The user in our just needs to compute five scale multiplication to finish the key agreement. We also show the proposed protocol is secure in the random oracle model.
Hasse theorem -- an elementary approach
Jianhua Chen,Debiao He,Zhijin Hu,Yitao Chen,Hao Hu
Mathematics , 2012,
Abstract: We give an elementary proof to Hasse theorem.
Nanotechnologies for Curcumin: An Ancient Puzzler Meets Modern Solutions
Shengpeng Wang,Miao Tan,Zhangfeng Zhong,Meiwan Chen,Yitao Wang
Journal of Nanomaterials , 2011, DOI: 10.1155/2011/723178
Abstract: Curcumin, a low-molecular-weight natural polyphenol mainly found in the plant Curcuma longa (turmeric), is widely used as a food colorant and as a potential protective agent against several chronic diseases including cancer, HIV-infection, neurological, cardiovascular, and skin diseases. Moreover, evidences from long-term use process and preclinical trials have demonstrated low toxicity of curcumin, even at relatively high doses. However, it has been well known that the application of curcumin was limited owing to its water insolubility, instability, and poor bioavailability. For decades, many attempts have been made to compensate for these disadvantages, with the development of improved delivery platforms as the feasible approaches. The past ten years witnessed the encouraging progress in the use of nanoscale drug delivery systems on curcumin such as loading curcumin into liposomes or nanoparticles, forming self-microemulsifying drug delivery systems (SMEDDS), cyclodextrin inclusions, and solid dispersions, as well as the latest reported technologies such as nadodisks and nanotubes. This paper summarizes the recent works on the design and development of nanoscale delivery systems of curcumin, with the goal of harnessing the true difficulties of this multifunctional agent in the clinical arena. 1. Introduction Curcumin (Figure 1), an active constituent mainly derived from Curcuma longa (turmeric), is a natural yellow-orange polyphenol which has been used for its medicinal benefits for centuries [1, 2]. Curcumin was firstly extracted in impure form in 1815, then in 1870 the pure crystalline state was prepared. Almost three decades later, its composition was finally elucidated as 1, 6-heptadiene-3, 5-dione-1, 7-bis-(4-hydroxy-3-methoxyphenyl)-(1E, 6E) [3–6]. In China, curcumin has been used as a part of herbal medicine for centuries to alleviate throbbing pain in the chest and hypochondriac region, mass in abdomen, and pain of the shoulder due to win-cold or traumatic injuries. The accumulating of experimental and clinical evidences indicates that curcumin has a variety of pharmacological activities, such as antitumor, antiinflammatory, antivirus, antioxidation, anti-HIV, and low toxicity [7–11]. Figure 1: Chemical structure of curcumin. However, good things never come easy. Applicational advancement of curcumin has been hindered by its water insolubility, degradation at alkaline pH, and photodegradation and thus extremely low bioavailability in both vascular and oral administration [12, 13]. Therefore, many approaches have been investigated, including
Recent advances in nanoparticle formulation of oleanolic acid
Meiwan Chen, Zhangfeng Zhong, Wen Tan, Shengpeng Wang, Yitao Wang
Chinese Medicine , 2011, DOI: 10.1186/1749-8546-6-20
Abstract: Oleanolic acid (OA), a naturally occurring pentacyclic triterpenoid extracted from the leaves and roots of Olea europaea, Viscum album L., Aralia chinensis L. and over 120 other plant species [1], is chemically known as 3β-hydroxy-olea-12-en-28-oic acid [2] (Figure 1). OA exhibits many biological activities such as anti-inflammatory, antitumor, antiviral, hepatoprotective and anti-hyperlipidemic effects. OA has been used in Chinese medicine to treat liver disorders for over 20 years [2]. Conventional formulations of OA are tablets and capsules [3]; however, OA's poor aqueous solubility and low bioavailability in vivo make it necessary to develop new formulations for clinical applications.Derived from nanotechnology, nanoparticulate delivery system provides an innovative approach to drug delivery [4-7]; nanoparticulate technique reduces particles to nanometer ranges, thus reducing the dose and reactive nature of the molecule [8]. Various nanoparticulate drug delivery systems have been explored, such as nanoparticles, nanospheres, nanocapsules, solid lipid nanoparticles (SLN), self-emulsifying drug delivery systems (SEDDS) and submicron/nanoemulsions [9][10]. Compared to conventional dosage forms, nanoparticulate drug delivery system has many advantages, namely enhancement of solubility and stability, protection from toxicity, enrichment of pharmacological activities, improvement of tissue macrophage distribution, bioavailability and sustained delivery, protection from physical and chemical degradation [7,11].This article reviews recent advances in nanoparticulate formulation of OA.Solid lipid nanoparticles (SLN), which remain solid at room temperature, have emerged as a new pharmaceutical delivery system or formulation to modify the release profile for many drugs [12]. SLN has characteristics of drug carriers such as lipophilicity, hydrophilicity as well as low bio-toxicity. Main advantages of SLN include: controlling drug release, targeting with reduced toxicity, in
PP2A-Mediated Anticancer Therapy
Weibo Chen,Zhongxia Wang,Chunping Jiang,Yitao Ding
Gastroenterology Research and Practice , 2013, DOI: 10.1155/2013/675429
Abstract: PP2A is a family of mammalian serine/threonine phosphatases that is involved in the control of many cellular functions including protein synthesis, cellular signaling, cell cycle determination, apoptosis, metabolism, and stress responses through the negative regulation of signaling pathways initiated by protein kinases. Rapid progress is being made in the understanding of PP2A complex and its functions. Emerging studies have correlated changes in PP2A with human diseases, especially cancer. PP2A is comprised of 3 subunits: a catalytic subunit, a scaffolding subunit, and a regulatory subunit. The alternations of the subunits have been shown to be in association with many human malignancies. Therapeutic agents targeting PP2A inhibitors or activating PP2A directly have shed light on the therapy of cancers. This review focuses on PP2A structure, cancer-associated mutations, and the targeting of PP2A-related molecules to restore or reactivate PP2A in anticancer therapy, especially in digestive system cancer therapy. 1. Introduction Protein phosphatase 2A(PP2A) is a member of phosphoprotein phosphatase (PPP) family which belongs to the superfamily of protein serine/threonine phosphatases that reverse the actions of protein kinases by cleaving phosphate from serine and threonine residues of proteins. It has been proven that PP2A regulates various cellular processes, including protein synthesis, cellular signaling, cell cycle determination, apoptosis, metabolism, and stress responses [1–3]. PP2A is widely described as a tumor suppressor since the first recognition that its inhibitor okadaic acid is a tumor promoter, and mutations of PP2A subunits can be detected in a variety of human malignancies. The tumor suppressing function of PP2A makes it a possible target in anticancer therapy. Colorectal cancer is the third most common cancer in males and the second in females, and about 25% of patients with colorectal cancer present with overt metastatic disease. Forty to 50% of newly diagnosed patients can develop metastasis [4, 5]. Liver cancer is the fifth most common cancer in males and the seventh most in females worldwide. It ranks the third in cancer-related deaths [5]. Hepatocellular carcinoma (HCC) which account for 70–85% of primary malignancies in liver is the dominant histological type of primary liver cancer [6]. To date, the treatment of these two cancers is not satisfactory, and the discovery of new therapeutic agents is in demand. Among all the possible targets, PP2A is a promising one. In this review, we focus on the structure of PP2A and the possible
Anti-Lung-Cancer Activity and Liposome-Based Delivery Systems of β-Elemene
Meiwan Chen,Jinming Zhang,Siqin Yu,Shengpeng Wang,Zaijun Zhang,Jianqiang Chen,Jian Xiao,Yitao Wang
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/259523
Abstract: In the past decade, β-elemene played an important role in enhancing the effects of many anticancer drugs and was widely used in the treatment of different kinds of malignancies and in reducing the side effects of chemotherapy. Further study showed that it is also a promising anti-lung cancer drug. However, the clinical application of β-elemene was limited by its hydrophobic property, poor stability, and low bioavailability. With the development of new excipients and novel technologies, plenty of novel formulations of β-elemene have improved dramatically, which provide a positive perspective in terms of clinical application for β-elemene. Liposome as a drug delivery system shows great advantages over traditional formulations for β-elemene. In this paper, we summarize the advanced progress being made in anti-lung cancer activity and the new liposomes delivery systems of β-elemene. This advancement is expected to improve the level of pharmacy research and provide a stronger scientific foundation for further study on β-elemene.
Antioxidant, Antityrosinase and Antitumor Activity Comparison: The Potential Utilization of Fibrous Root Part of Bletilla striata (Thunb.) Reichb.f.
Fusheng Jiang, Weiping Li, Yanfen Huang, Yitao Chen, Bo Jin, Nipi Chen, Zhishan Ding, Xinghong Ding
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0058004
Abstract: This study was carried out to evaluate the utilization probability of the fibrous root part (FRP) of Bletilla striata, which was usually discarded and harvesting pseudobulb part (PSP). The chemical composition, total phenolic content, DPPH radical scavenging activity, Ferric-reducing antioxidant power and tyrosinase inhibition activity were compared between FRP and PSP. Antioxidant and pro-oxidant effect as well as antitumor effect of the extract of FRP and PSP were analyzed by in vitro cell system as well. Thin layer chromatography and high performance liquid chromatography analysis indicated that the chemical compositions in the two parts were similar, but the content in FRP was much higher than PSP. Meanwhile, the FRP extracts showed higher phenolic content, stronger DPPH scavenging activity, Ferric-reducing antioxidant capacity and tyrosinase inhibition activity. Sub-fraction analysis revealed that the distribution characteristic of phenolic components and other active constituents in FRP and PSP were consistent, and mainly deposited in chloroform and acetoacetate fractions. Especially, the chloroform sub-fraction (sch) of FRP showed extraordinary DPPH scavenging activity and tyrosinase inhibition activity, with IC50 0.848 mg/L and 4.3 mg/L, respectively. Besides, tyrosinase inhibition activity was even stronger than the positive compound arbutin (31.8 mg/L). Moreover, In vitro cell system analysis confirmed that FRP extract exerts comparable activity with PSP, especially, the sub-fraction sch of FRP showed better antioxidant activity at low dosage and stronger per-oxidant activity at high dosage, and both sch of FRP and PSP can dose-dependent induce HepG2 cells apoptosis, which implied tumor therapeutic effect. Considering that an additional 0.3 kg FRP would be obtained when producing 1.0 kg PSP, our work demonstrated that FRP is very potential to be used together with PSP.
The Development Status and Problems of Current Digital Artistic Design
Yitao Zhou
Asian Social Science , 2009, DOI: 10.5539/ass.v4n11p79
Abstract: The entrance of digital technique into design field brings about tremendous changes, which are mainly shown in the view style of the mixture of objects and viewers. From this perspective, the formation of virtual images depends on computer calculation without any technique difficulties. The support of digital techniques pushes the development of online design mutual actions where culture holds its ground. Designers should shoulder their social responsibilities for loss of home land language design languages and its design context. We need to face all of the problems in the development process of digital artistic design need and to reflect on ourselves.
The Decomposition-combination Structure of the Chu Art in the Visual Field of Liuguan
Yitao Zhou
Asian Social Science , 2009, DOI: 10.5539/ass.v4n10p123
Abstract: The writing technique of the decomposition-recombination structure in the arts of the Chu state is based on the aesthetic orientation of Tao and the aesthetic attitude of “Liuguan”, which has constructed the aesthetic approach different from the other types of art. The aesthetic control of “Liuguan” has produced the artistic favor and flexibility. This text focuses on the formation bases of the decomposition-recombination structure and gives a further discussion of its unique features of the arts of the Chu State.
Existence of positive pseudo-symmetric solutions for one-dimensional p-Laplacian boundary-value problems
Yitao Yang
Electronic Journal of Differential Equations , 2007,
Abstract: We prove the existence of positive pseudo-symmetric solutions for four-point boundary-value problems with p-Laplacian. Also we present an monotone iterative scheme for approximating the solution. The interesting point here is that the nonlinear term f involves the first-order derivative.
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