X-rays are widely applied in clinical medical facilities for radiotherapy (RT) and biomedical imaging. However, the sole use of X-rays for cancer treatment leads to insufficient radiation energy ...deposition due to the low X-ray attenuation coefficients of living tissues and organs, producing unavoidable excessive radiation doses with serious side effects to healthy body parts. Over the past decade, developments in materials science and nanotechnology have led to rapid progress in the field of X-ray-activated tumor-targeting nanosystems, which are able to tackle even systemic tumors and relieve the burden of exposure to large radiation doses. Additionally, novel imaging contrast agents and techniques have also been developed. In comparison with conventional external light sources (
e.g.
, near infrared), the X-ray technique is ideal for the activation of nanosystems for cancer treatment and biomedical imaging applications due to its nearly unlimited penetration depth in living tissues and organisms. In this review, we systematically describe the interaction mechanisms between X-rays and nanosystems, and provide an overview of X-ray-sensitive materials and the recent progress on X-ray-activated nanosystems for cancer-associated theranostic applications.
We systematically provide an overview of X-ray-sensitive materials and the recent progress on X-ray-activated nanosystems for cancer-associated theranostic applications.
A vehicular ad-hoc network (VANET) can improve the flow of traffic to facilitate intelligent transportation and to provide convenient information services, where the goal is to provide ...self-organizing data transmission capabilities for vehicles on the road to enable applications, such as assisted vehicle driving and safety warnings. VANETs are affected by issues such as identity validity and message reliability when vehicle nodes share data with other nodes. The method used to allow the vehicle nodes to upload sensor data to a trusted center for storage is susceptible to security risks, such as malicious tampering and data leakage. To address these security challenges, we propose a data security sharing and storage system based on the consortium blockchain (DSSCB). This digital signature technique based on the nature of bilinear pairing for elliptic curves is used to ensure the reliability and integrity when transmitting data to a node. The emerging consortium blockchain technology provides a decentralized, secure, and reliable database, which is maintained by the entire network node. In DSSCB, smart contracts are used to limit the triggering conditions for preselected nodes when transmitting and storing data and for allocating data coins to vehicles that participate in the contribution of data. The security analysis and performance evaluations demonstrated that our DSSCB solution is more secure and reliable in terms of data sharing and storage. Compared with the traditional blockchain system, the time required to confirm the data block was reduced by nearly six times and the transmission efficiency was improved by 83.33%.
The adsorption of methyl orange onto multiwalled carbon nanotubes (MWCNTs) from aqueous solutions was studied, in which the influence of contact time, dosage, temperature, pH, and methyl orange ...concentration in the solution were investigated. The equilibrium adsorption data were analyzed using three common adsorption models: Langmuir, Freundlich and Temkin. The results revealed that Langmuir isotherm fit the experimental results well. Kinetic analyses were conducted using pseudo-first and second-order models and the intra-particle diffusion model. The regression results showed that the adsorption kinetics was more accurately represented by pseudo-second-order model. Values of activation parameters such as Standard free energy changes (Δ
G
0), standard enthalpy change (Δ
H
0), and standard entropy change (Δ
S
0) were calculated using adsorption equilibrium constants obtained from the Langmuir isotherm at different temperatures. All Δ
G
0 values were negative; the (Δ
H
0) values and (Δ
S
0) values of MWCNTs were 19.39
kJ/mol and 0.1015
kJ/mol K, respectively, indicating that the adsorption was feasible, spontaneous and endothermic process in nature.
Due to a failure of communication, the connections among multi-agent system may switch extremely frequently. This paper focuses on the consensus of a multi-agent system with double-integrator ...dynamics in a generalized uniformly jointly connected switching network environment without dwell time. We prove that the distributed controller is robust against unreliable communication. The stability of the closed-loop system is proved by a virtual output technique and the generalized Krasovskii-LaSalle theorem. To validate the effectiveness of the proposed controller, a simulation example including a uniformly jointly connected network with dwell time and generalized uniformly jointly connected network without dwell time is presented.
Data sharing becomes an exceptionally attractive service supplied by cloud computing platforms because of its convenience and economy. As a potential technique for realizing fine-grained data ...sharing, attribute-based encryption (ABE) has drawn wide attentions. However, most of the existing ABE solutions suffer from the disadvantages of high computation overhead and weak data security, which has severely impeded resource-constrained mobile devices to customize the service. The problem of simultaneously achieving fine-grainedness, high-efficiency on the data owner's side, and standard data confidentiality of cloud data sharing actually still remains unresolved. This paper addresses this challenging issue by proposing a new attribute-based data sharing scheme suitable for resource-limited mobile users in cloud computing. The proposed scheme eliminates a majority of the computation task by adding system public parameters besides moving partial encryption computation offline. In addition, a public ciphertext test phase is performed before the decryption phase, which eliminates most of computation overhead due to illegitimate ciphertexts. For the sake of data security, a Chameleon hash function is used to generate an immediate ciphertext, which will be blinded by the offline ciphertexts to obtain the final online ciphertexts. The proposed scheme is proven secure against adaptively chosen-ciphertext attacks, which is widely recognized as a standard security notion. Extensive performance analysis indicates that the proposed scheme is secure and efficient.
With the rapid development of cloud computing, cloud storage has been accepted by an increasing number of organizations and individuals, therein serving as a convenient and on-demand outsourcing ...application. However, upon losing local control of data, it becomes an urgent need for users to verify whether cloud service providers have stored their data securely. Hence, many researchers have devoted themselves to the design of auditing protocols directed at outsourced data. In this paper, we propose an efficient public auditing protocol with global and sampling blockless verification as well as batch auditing, where data dynamics are substantially more efficiently supported than is the case with the state of the art. Note that, the novel dynamic structure in our protocol consists of a doubly linked info table and a location array. Moreover, with such a structure, computational and communication overheads can be reduced substantially. Security analysis indicates that our protocol can achieve the desired properties. Moreover, numerical analysis and real-world experimental results demonstrate that the proposed protocol achieves a given efficiency in practice.
In this paper, the complex-valued neural networks with both leakage time delay and discrete time delay as well as two types of activation functions on time scales are considered. By using the fixed ...point theory, a criterion for checking the existence, uniqueness of the equilibrium point for the considered complex-valued neural networks is presented. By constructing appropriate Lyapunov–Krasovskii functionals, and employing the free weighting matrix method, several delay-dependent criteria for checking the global stability of the addressed complex-valued neural networks are established in linear matrix inequality (LMI), which can be checked numerically using the effective LMI toolbox in MATLAB. Three examples with simulations are given to show the effectiveness and less conservatism of the proposed criteria.
The synchronization problem for heterogeneous harmonic oscillators is investigated. In practice, the communication network among oscillators might suffer from equipment failures or malicious attacks. ...The connection may switch extremely frequently without dwell time, and can thus be described by generalized uniformly jointly connected networks. We show that the presented typical control law is strongly robust against various unreliable communications. Combined with the virtual output approach and generalized Krasovskii-LaSalle theorem, the stability is proved with the help of its cascaded structure. Numerical examples are presented to show the correctness of the control law.
The notion of verifiable database (VDB) enables a resource-constrained client to securely outsource a very large database to an untrusted server so that it could later retrieve a database record and ...update a record by assigning a new value. Also, any attempt by the server to tamper with the data will be detected by the client. When the database undergoes frequent while small modifications, the client must re-compute and update the encrypted version (ciphertext) on the server at all times. For very large data, it is extremely expensive for the resources-constrained client to perform both operations from scratch. In this paper, we formalize the notion of verifiable database with incremental updates (Inc-VDB). Besides, we propose a general Inc-VDB framework by incorporating the primitive of vector commitment and the encrypt-then-incremental MAC mode of encryption. We also present a concrete Inc-VDB scheme based on the computational Diffie-Hellman (CDH) assumption. Furthermore, we prove that our construction can achieve the desired security properties.
Current X-ray imaging technologies involving flat-panel detectors have difficulty in imaging three-dimensional objects because fabrication of large-area, flexible, silicon-based photodetectors on ...highly curved surfaces remains a challenge
. Here we demonstrate ultralong-lived X-ray trapping for flat-panel-free, high-resolution, three-dimensional imaging using a series of solution-processable, lanthanide-doped nanoscintillators. Corroborated by quantum mechanical simulations of defect formation and electronic structures, our experimental characterizations reveal that slow hopping of trapped electrons due to radiation-triggered anionic migration in host lattices can induce more than 30 days of persistent radioluminescence. We further demonstrate X-ray luminescence extension imaging with resolution greater than 20 line pairs per millimetre and optical memory longer than 15 days. These findings provide insight into mechanisms underlying X-ray energy conversion through enduring electron trapping and offer a paradigm to motivate future research in wearable X-ray detectors for patient-centred radiography and mammography, imaging-guided therapeutics, high-energy physics and deep learning in radiology.
PDF
