355 research outputs found
Comments of an efficient and secure multi-server authentication scheme with key agreement
Recently, Tsaur et al. proposed an authentication scheme for multi-server environments and claimed their scheme could withstand various attacks. In this letter, we will point out that Tsaur et al. scheme is not suitable for multi-server environments since the user has to register for every server. Furthermore, we will show Tsaur et al. scheme is vulnerable to the password guessing attack and the privileged insider attack
Berberine hydrochloride: anticancer activity and nanoparticulate delivery system
Wen Tan, Yingbo Li, Meiwan Chen, Yitao WangState Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao Special Administrative Region, ChinaBackground: Berberine hydrochloride is a conventional component in Chinese medicine, and is characterized by a diversity of pharmacological effects. However, due to its hydrophobic properties, along with poor stability and bioavailability, the application of berberine hydrochloride was hampered for a long time. In recent years, the pharmaceutical preparation of berberine hydrochloride has improved to achieve good prospects for clinical application, especially for novel nanoparticulate delivery systems. Moreover, anticancer activity and novel mechanisms have been explored, the chance of regulating glucose and lipid metabolism in cancer cells showing more potential than ever. Therefore, it is expected that appropriate pharmaceutical procedures could be applied to the enormous potential for anticancer efficacy, to give some new insights into anticancer drug preparation in Chinese medicine.Methods and results: We accessed conventional databases, such as PubMed, Scope, and Web of Science, using “berberine hydrochloride”, “anti-cancer mechanism”, and “nanoparticulate delivery system” as search words, then summarized the progress in research, illustrating the need to explore reprogramming of cancer cell metabolism using nanoparticulate drug delivery systems.Conclusion: With increasing research on regulation of cancer cell metabolism by berberine hydrochloride and troubleshooting of issues concerning nanoparticulate delivery preparation, berberine hydrochloride is likely to become a natural component of the nanoparticulate delivery systems used for cancer therapy. Meanwhile, the known mechanisms of berberine hydrochloride, such as decreased multidrug resistance and enhanced sensitivity of chemotherapeutic drugs, along with improvement in patient quality of life, could also provide new insights into cancer cell metabolism and nanoparticulate delivery preparation.Keywords: berberine hydrochloride, anticancer mechanisms, nanoparticulate drug progres
An efficient certificateless authenticated key agreement protocol without bilinear pairings
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
Synthesizing Ti–Ni Alloy Composite Coating on Ti–6Al–4V Surface from Laser Surface Modification
In This Work, a Ni-Alloy Deloro-22 Was Laser-Deposited on a Ti–6Al–4V Bar Substrate with Multiple Sets of Laser Processing Parameters. the Purpose Was to Apply Laser Surface Modification to Synthesize Different Combinations of Ductile TiNi and Hard Ti2Ni Intermetallic Phases on the Surface of Ti–6Al–4V in Order to Obtain Adjustable Surface Properties. Scanning Electron Microscopy, Energy Dispersion Spectroscopy, and X-Ray Diffraction Were Applied to Reveal the Deposited Surface Microstructure and Phase. the Effect of Processing Parameters on the Resultant Compositions of TiNi and Ti2Ni Was Discussed. the Hardness of the Deposition Was Evaluated, and Comparisons with the Ti–6Al–4V Bulk Part Were Carried Out. They Showed a Significant Improvement in Surface Hardness on Ti–6Al–4V Alloys after Laser Processing, and the Hardness Could Be Flexibly Adjusted by using This Laser-Assisted Surface Modification Technique
Recent advances in nanoparticle formulation of oleanolic acid
Oleanolic acid (OA) is a natural triterpenoid possessing anti-inflammatory, antitumor, antiviral, hepatoprotective and antihyperlipidemic effects. Research on the pharmacological activities and clinical applications of OA has made significant progress in the past decade, particularly in the areas such as isolation and purification, chemical modifications, pharmacological research, toxicity studies and clinical use of OA. However, due to its poor aqueous solubility, instability and low bioavailability, OA's clinical applications are still rather limited. Recently, nanoparticulate drug delivery as the biological dimension of nanotechnology has been developed, which may help generate useful formulations of OA for clinical applications. Nanoparticulate drug delivery system enhances the dissolution rate and bioavailability of OA, providing a feasible formulation method for clinical applications
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