In cloud computing,data service outsourcing relieves the data owners of the burden of local data storage and maintenance.However,it also eliminates their physical control of the storage dependability and security,which makes the outsourced data assurances in cloud computing a very challenging and potentially formidable task.Based on the overall study of the recent researches on data storage security,it introduced the architecture of cloud data storage firstly.And studied the state-of-the-art schemes from proofs of retrievability and provable data possession.Then,this paper discussed the function design in protocol based on public verification,homomorphic authenticators,data dynamics,data privacy protection,batch auditing and multiple-server environment.Furthermore,made some comparisons of functions and the complexity in different protocols in tables.At last,summarized and discussed the further direction of research.
A transplanted organ is always rejected in the absence of any immunosuppressive treatment due to vigorous alloimmunity. However, continuously global immunosuppression with a conventional immunosuppressant may result in severe side effects, including nephrotoxicity, tumors and infections. Tregs have been widely used to inhibit allograft rejection, especially in animal models. However, it's well accepted that administration of Tregs alone is not satisfactory in immune-competent wild-type animals. Therefore, it's imperative to promote Treg therapies under the cover of other approaches, including costimulatory blockade. In the present study, we demonstrated that administration of in vitro-expanded CD8+CD122+PD-1+ Tregs synergized with costimulatory blockade of CD40/CD154, but not B7/CD28, to prolong skin allograft survival in wild-type mice and to reduce cellular infiltration in skin allografts as well. Treg treatment and blockade of CD40/CD154, but not B7/CD28, also exhibited an additive effect on suppression of T cell proliferation in vitro and pro-inflammatory cytokine expression in skin allografts. Importantly, blocking B7/CD28, but not CD40/CD154, costimulation decreased the number of transferred CD8+CD122+PD-1+ Tregs and their expression of IL-10 in recipient mice. Furthermore, it's B7/CD28, but not CD40/CD154, costimulatory blockade that dramatically reduced IL-10 production by CD8+CD122+PD-1+ Tregs in vitro, suggesting that B7/CD28, but not CD40/CD154, costimulation is critical for their production of IL-10. Indeed, infusion of IL-10-deficient CD8+CD122+PD-1+ Tregs failed to synergize with anti-CD154 Ab treatment to further prolong allograft survival. Our data may explain why blocking B7/CD28 costimulatory pathway does not boost IL-10-dependent Treg suppression of alloimmunity. Thus, these findings could be implicated in clinical organ transplantation.
Traditional Chinese Medicine (TCM) has been traditionally used to treat patients with cancers in China. It not only alleviates the symptoms of tumor patients and improves their quality of life, but also controls the size of tumors and prolongs the survival of tumor patients. While some herbs of TCM may exert therapeutic effects by directly targeting cancer cells or reducing side effects caused by antitumor drugs, others can control tumor growth and metastasis via enhancing antitumor immunity. In particular, TCM can exert antitumor effects by upregulating immune responses even in immunosuppressive tumor microenvironment. For instance, it reduces the number of M2-type macrophages and Treg cells in the tumor tissue. Although extensive reviews on directly killing cancer cells by TCM have been conducted, a review of anticancer activity of TCM solely based on its immunity-enhancing capacity is unusual. This review will summarize research progress of antitumor TCM that regulates the immune system, including both innate immunity, such as macrophages, dendritic cells, natural killer cells and MDSCs, and adaptive immunity, including CD4+/CD8+ T lymphocytes, regulatory T cells (Tregs) and B cells. As cancer immunotherapy has recently achieved certain success, it is expected that the clinical applications of immunity-enhancing TCM or traditional medicine for treating various cancer patients will be expanded. Further studies on the mechanisms by which TCM regulates immunity will provide new insights into how TCM controls tumor growth and metastasis, and may help improve its therapeutic effects on various cancers in clinic.
Virtualization technology becomes a hot IT technology with the popu-larity of CloudComputing.However, new security issues arise with it.Specifically, the resources sharing and data communication in virtual machines are most concerned.In this paper an access control model is proposed which combines the Chinese Wall and BLP model.BLP multi-level security model is introduced with corresponding improvement based on PCW (Prioritized Chinese Wall) security model.This model can be used to safely control the resources and event behaviors in virtual machines.Experimental results show its effectiveness and safety.
A transplanted organ is usually rejected without any major immunosuppressive treatment because of vigorous alloimmune responsiveness. However, continuous global immunosuppression may cause severe side effects, including nephrotoxicity, tumors and infections. Therefore, it is necessary to seek novel immunosuppressive agents, especially natural ingredients that may provide sufficient efficacy in immunosuppression with minimal side effects. Shikonin is a bioactive naphthoquinone pigment, an ingredient originally extracted from the root of Lithospermum erythrorhizon. Previous studies have shown that shikonin regulates immunity and exerts anti-inflammatory effects. In particular, it can ameliorate arthritis in animal models. However, it is unclear whether shikonin inhibits alloimmunity or allograft rejection. In this study and for the first time, we demonstrated that shikonin significantly prolonged the survival of skin allografts in wild-type mice. Shikonin increased the frequencies of CD4+Foxp3+ regulatory T cells (Tregs) post-transplantation and induced CD4+Foxp3+ Tregs in vitro as well. Importantly, depleting the Tregs abrogated the extension of skin allograft survival induced by shikonin. It also decreased the frequencies of CD8+CD44highCD62Llow effector T cells and CD11c+CD80+/ CD11c+CD86+ mature DCs after transplantation. Moreover, we found that shikonin inhibited the proliferation of T cells in vitro and suppressed their mTOR signaling. It also reduced the gene expression of pro-inflammatory cytokines, including IFNγ, IL-6, TNFα and IL-17A, while increasing the gene expression of anti-inflammatory mediators IL-10, TGF-β1 and indoleamine-2, 3-dioxygenase (IDO) in skin allografts. Further, shikonin downregulated IDO protein expression in skin allografts and DCs in vitro. Taken together, shikonin inhibits allograft rejection via upregulating CD4+Foxp3+ Tregs. Thus, shikonin is a novel immunosuppressant that could be potentially used in clinical transplantation.
Background: Ferroptosis is a new form of regulated cell death characterized by the accumulation of iron-dependent lipid peroxides and membrane damages. Recent studies have identified an important role for cancer cell ferroptosis in antitumor therapy. On the other hand, polyphyllin I (PPI) has been reported to exert antitumor effects on some types of cancers. However, it remains unknown whether or not PPI regulates cancer cell ferroptosis. Methods: Two types of human gastric cancer cells (AGS and MKN-45) were used to establish tumor xenograft models in nude mice that were treated with polyphyllin I (PPI) to observe tumor growth, while cells also were cultured for in vitro studies. Ferroptosis, based on the intracellular ROS/lipid ROS production and accumulation of ferrous ions, was detected using a fluorescence microscope and flow cytometer, while the expression of NRF2/FTH1 was measured using Western blotting assays. Results: Here we found that PPI inhibited the gastric cancer growth in vivo and in vitro while increasing the intracellular reactive oxygen species (ROS)/lipid peroxides and ferrous ions in the gastric cancer cells. PPI also decreased the levels of nuclear factor erythroid 2-related factor 2 (NRF2) and ferritin heavy chain 1 (FTH1) in gastric cancer cells in vitro. Moreover, liproxstain-1, an inhibitor of cell ferroptosis, mostly reversed the cell ferroptosis and tumor growth arrest induced by PPI. Finally, the effects of PPI on cancer cell ferroptosis were diminished by the overexpression of NRF2. Conclusion: For the first time, our results have demonstrated that PPI exerts its antitumor activity on the gastric cancer by, at least partially, inducing cancer cell ferroptosis via regulating NRF2/FTH1 pathway. These findings may be implicated for clinical replacement therapy of the gastric cancer.
With its unique technical advantages, virtual reality (VR) is being used in almost all human practical activities, such as industry, agriculture, commerce, education, military and so on. VR technology will play a key role in our further life. It is necessary to analyze all aspects of VR technology systematically to help the development of virtual reality technology. In this article, the basic concept of VR technology, the basic technologies it contains, the characteristics of VR technology and its development process are introduced, further, the main difficulties faced by the current VR technology development are analyzed, and the possible solutions are discussed. The main difficulties faced by VR technology at present are essentially due to its high-speed development. The rapid development of VR has led to a variety of choices of technical routes, difficulty in establishing industrial standards and confusion of users. On the one hand, these difficulties depend on the technology development itself; on the other hand, the active involvement of the government or relevant institutions can also effectively promote the development of VR.
In order to study the possibility of aerodynamic optimization of the base cavity for slender body, the influence of base cavity with non-cylindrical shape, which is different from the traditional column one, is investegated by numerical method in the paper. The supersonic flow field of same slender body with two sorts of unconventional base cavity, which is half truncated-cone and half column, is simulated by axisymmetric Navier-Stokes equations. Distribution of Mach Number (Ma), streamline, temperature and pressure of the flow field; the aerodynamic drag of the slender body were calculated. Compared with the traditional cylindrical base cavity structure, results show that, the appropriate non-cylindrical base cavity is helpful to decrease the aerodynamic drag of slender body. In the paper’s simulation, the slender body with the base cavity of half truncated-cone (negative inclination) and half column shape has the smallest aerodynamic drag. The cylindrical base cavity structure, which is widely used to reduce the aerodynamic drag, there are spaces to further optimize still.
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