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ABE has become an effective tool for data protection in cloud computing. However, since users possessing the same attributes share the same private keys, there exist some malicious users exposing their private keys deliberately for illegal data sharing without being detected, which will threaten the security of the cloud system. Such issues remain in many current ABE schemes since the private keys are rarely associated with any user specific identifiers. In order to achieve user accountability as well as provide key exposure protection, in this paper, we propose a key-insulated ciphertext policy attribute based encryption with key exposure accountability (KI-CPABE-KEA). In our scheme, data receiver can decrypt the ciphertext if the attributes he owns match with the self-centric policy which is set by the data owner. Besides, a unique identifier is embedded into each user's private key. If a malicious user exposes his private key for illegal data sharing, his identity can be exactly pinpointed by system manager. The key-insulation mechanism guarantees forward and backward security when key exposure happens as well as provides efficient key updating for users in the cloud system. The higher efficiency with proved security make our KI-CPABE-KEA more appropriate for secure data sharing in cloud computing. [ABSTRACT FROM AUTHOR]

Multi-authority attribute-based encryption (ABE) is a generation of ABE where the descriptive attributes are managed by different authorities. In current multi-authority ABE schemes, the scale of attribute universe employed in encryption is restricted by various predefined thresholds. In this paper, we propose an unbounded multi-authority ciphertext-policy ABE system without such restriction. Our scheme consists of multiple attribute authorities (AAs), one central authority (CA), and users labeled by the set of attributes. Each AA governs a different universe of attributes and operates separately. Moreover, there is no cooperation between the CA and AAs. To provide the private keys for a user, the AAs first issue partial attribute-related keys according to the attributes; the CA then issues identity-related keys and links these attribute-keys with the user's global identifier. Both the identity-related and the linked attribute-related keys will be used in decryption. The proposed multi-authority ciphertext-policy ABE scheme can support arbitrary linear secret sharing scheme as the access policy. Performance analysis and security proof indicate that our scheme is efficient and secure. [ABSTRACT FROM AUTHOR]

Each cloud service has numerous owners and tenants, so it is necessary to construct a privacy preserving identity management and access control mechanism for cloud computing. On one hand, cloud service providers (CSP) depend on tenant's identity information to enforce appropriate access control so that cloud resources are only accessed by the authorized tenants who are willing to pay. On the other hand, tenants wish to protect their personalized service access patterns, identity privacy information and accessing newfangled cloud services by on-demand ways within the scope of their permissions. There are many identity authentication and access control schemes to address these challenges to some degree, however, there are still some limitations. In this paper, we propose a new comprehensive approach, called Privacy p Reserving Identity and Access Management scheme, referred to as PRIAM, which is able to satisfy all the desirable security requirements in cloud computing. The main contributions of the proposed PRIAM scheme are threefold. First, it leverages blind signature and hash chain to protect tenant's identity privacy and implement secure mutual authentication. Second, it employs the service-level agreements to provide flexible and on-demand access control for both tenants and cloud services. Third, it makes use of the BAN logic to formally verify the correctness of the proposed protocols. As a result, our proposed PRIAM scheme is suitable to cloud computing thanks to its simplicity, correctness, low overhead, and efficiency. [ABSTRACT FROM AUTHOR]

Bone formation is carried out by the osteoblast, a mesenchymal cell whose lifespan and activity are regulated by growth factor signaling networks. Growth factors activate phosphatidylinositol 3-kinase (P13K), which enhances cell survival and antagonizes apoptosis through activation of Akt/PKB. This process is negatively regulated by the Pten phosphatase. which inhibits the activity of PI3K. In this study, we investigated the effects of Akt activation in bone in vivo by conditionally disrupting the Pten gene in osteoblasts by using Cre-mediated recombination. Mice deficient in Pten in osteoblasts were of normal size but demonstrated a dramatic and progressively increasing bone mineral density throughout life. In vitro osteoblasts lacking Pten differentiated more rapidly than controls and exhibited greatly reduced apoptosis in association with markedly increased levels of phosphorylated Akt and activation of signaling pathways downstream of activated Akt. These findings support a critical role for this tumor-suppressor gene in regulating osteobtast lifespan and likely explain the skeletal abnormalities in patients carrying germ-line mutations of PTEN. [ABSTRACT FROM AUTHOR]

Highly active and stable electrocatalysts based on non-precious metals for hydrogen evolution reaction (HER) in alkaline solution are urgently required for enabling mass production of clean hydrogen in industry. Herein, core–shell NiOOH/Ni nanoarchitectures supported on the conductive carbon cloth have been successfully prepared by a facile electrodeposition process of Ni, and a subsequent in situ electrochemical oxidation. When explored as an alkaline HER electrocatalyst, the as-synthesized NiOOH/Ni nanoarchitecture requires only a low overpotential of ∼111 mV to attain a current density of −10 mA cm−2, demonstrating its strong catalytic capability of hydrogeneration. The excellent HER activity could well be attributed to the decreasing charge transfer resistance and competitive electrochemical active area of the amorphous NiOOH, compared with inactive Ni substrate. The feasible methodology established in this study can be easily expanded to obtain a series of nano-sized metal oxyhydroxide materials for various energy conversion and storage applications, where Ni-based nanomaterials are among the highly active ones. [ABSTRACT FROM AUTHOR]

Federated learning (FL) allows multiple participants to collaboratively build deep learning (DL) models without directly sharing data. Consequently, the issue of copyright protection in FL becomes important since unreliable participants may gain access to the jointly trained model. Application of homomorphic encryption (HE) in a secure FL framework prevents the central server from accessing plaintext models. Thus, it is no longer feasible to embed the watermark at the central server using existing watermarking schemes. In this article, we propose a novel client-side FL watermarking scheme to tackle the copyright protection issue in secure FL with HE. To the best of our knowledge, it is the first scheme to embed the watermark to models under a secure FL environment. We design a black-box watermarking scheme based on client-side backdooring to embed a pre-designed trigger set into an FL model by a gradient-enhanced embedding method. Additionally, we propose a trigger set construction mechanism to ensure that the watermark cannot be forged. Experimental results demonstrate that our proposed scheme delivers outstanding protection performance and robustness against various watermark removal attacks and ambiguity attack. [ABSTRACT FROM AUTHOR]

Community structure is a typical characteristic of complex networks. Finding communities in complex networks has many important applications, such as the advertisement and recommendation based on social networks and the discovery of new protein molecules in biological networks, which make it a hot topic in the field of complex network analysis. With the increasing concerns about the leakage of personal privacy, discovering communities spread across the local networks owned by multiple participants accurately while preserving each participant's privacy has become an emerging challenge in distributed community detection. In this article, we propose a general federated graph learning model for privacy-preserving distributed graph learning and develop two federated clique percolation algorithms (CPAs) based on it to discover overlapping communities distributed across multiple participants' local networks without disclosing any participant's network privacy. Homomorphic encryption and hash operation are used in combination to protect the privacy of the vertices and edges of each local network. Furthermore, vertex attributes are involved in the calculation of clique similarity and clique percolation when dealing with attributed networks. The experimental results on real-world and artificial datasets demonstrate that the proposed algorithms achieve identical results to those of their stand-alone counterparts and more than 200% higher accuracy than the simple distributed CPAs without federating learning. [ABSTRACT FROM AUTHOR]

The National Natural Science Foundation of China (hereinafter referred to as the Natural Science Foundation of China) is responsible for effectively utilizing the National Natural Science Foundation of China, supporting basic research, adhering to free exploration, playing a guiding role, and discovering and cultivating science and technology in accordance with the national guidelines, policies and plans for the promotion of scientific and technological progress and coordinated economic and social development.With the continuous development of new productive forces represented by information technology, the Natural Science Foundation of China has been committed to promoting the informatization and intelligence of fund management.With the increasing complexity of business types, various types of network attacks, such as information leakage attacks, are encountered in the construction of informatization and make network security face severe challenges.The network security construction of the Natural Science Foundation of China was took as the main line and the network security construction of the existing platform was introduced.At present, a network security system structure with the science fund project management as the core has been established to ensure the safe and stable operation of the network system.The main information systems of the Natural Science Foundation of China (Natural Science Foundation Shared Service Network, business department website, email system) and its main threats were analyzed and introduced.Then the thoughts and suggestions in the follow-up informatization and network security construction were given.The Natural Science Foundation of China will start the construction of a new generation of secure network.Under the premise of fully considering the characteristics of science fund review, management, and open sharing, it will achieve the overall goal of “smarter, safer, and better” and carry out network security system construction for relevant units.

To determine whether receptors for B lymphocyte stimulator (BLyS) are altered on B cells of patients with systemic lupus erythematosus (SLE).Total available receptors for BLyS were measured by analysis of binding of recombinant soluble BLyS to peripheral blood B cells in 36 SLE patients, 29 healthy controls, and 10 disease controls. Antibodies to the receptors BAFF‐R, BCMA, and TACI were used to define expression of the individual BLyS receptors on subsets of B cells in blood, spleen, and tonsils. Two different antibodies to BAFF‐R, which were differentially sensitive to BAFF‐R occupancy, were used to compare BAFF‐R on B cells in an additional 20 healthy subjects and 25 SLE patients. Assays of B cell survival after stimulation in vitro were used to determine the sensitivity of B cells to exogenous BLyS.Total available receptors for BLyS were decreased in patients with SLE, independent of changes of subsets in the blood in these patients. The decrease correlated with changes in disease activity. Although total surface BAFF‐R was not significantly different between healthy controls and SLE patients, BAFF‐R was occupied in SLE patients. B cells from these patients were less responsive to exogenous BLyS.BAFF‐R is consistently occupied on blood B cells in SLE. Occupancy of BAFF‐R on blood B cells is likely to contribute to disease mechanisms in SLE and could serve as a biomarker of disease activity. Targeting BLyS as a therapeutic strategy will require overcoming the persistent binding of BLyS to BAFF‐R. [ABSTRACT FROM AUTHOR]

The article presents a study that explores the loss of activating transcription factor 4 (ATF4) leads to functional aging-like attrition of adult hematopoietic stem cells . It mentions that aging of hematopoietic stem cells (HSCs) directly contributes to dysfunction of hematopoietic and immune systems due to aging-associated alterations in HSC features.

Skeletal development and turnover occur in close spatial and temporal association with angiogenesis. Osteoblasts are ideally situated in bone to sense oxygen tension and respond to hypoxia by activating the hypoxia-inducible factor (HIF) pathway. Here we provide evidence that HIF promotes angiogenesis and osteogenesis by elevating VEGF levels in osteoblasts. Mice overexpressing HIF in osteoblasts through selective deletion of the von Hippel–Lindau gene (Vhl) expressed high levels of Vegf and developed extremely dense, heavily vascularized long bones. By contrast, mice lacking Hif1a in osteoblasts had the reverse skeletal phenotype of that of the Vhl mutants: long bones were significantly thinner and less vascularized than those of controls. Loss of Vhl in osteoblasts increased endothelial sprouting from the embryonic metatarsals in vitro but had little effect on osteoblast function in the absence of blood vessels. Mice lacking both Vhl and Hif1a had a bone phenotype intermediate between those of the single mutants, suggesting overlapping functions of HIFs in bone. These studies suggest that activation of the HIF pathway in developing bone increases bone modeling events through cell-nonautonomous mechanisms to coordinate the timing, direction, and degree of new blood vessel formation in bone. [ABSTRACT FROM AUTHOR]