53 research outputs found
Migration control for mobile agents based on passport and visa
Research on mobile agents has attracted much attention as this paradigm has demonstrated great potential for the next-generation e-commerce. Proper solutions to security-related problems become key factors in the successful deployment of mobile agents in e-commerce systems. We propose the use of passport and visa (P/V) for securing mobile agent migration across communities based on the SAFER e-commerce framework. P/V not only serves as up-to-date digital credentials for agent-host authentication, but also provides effective security mechanisms for online communities to control mobile agent migration. Protection for mobile agents, network hosts, and online communities is enhanced using P/V. We discuss the design issues in details and evaluate the implementation of the proposed system
Privacy-Preserving Predicate Proof of Attributes with CL-Anonymous Credential
Abstract The anonymous credential system allows users to convince relying parties the possession of a credential released by an issuer. To adhere to the minimal information disclose principle, the anonymous credential facilitates predicate proofs of attributes without revealing the values. In this paper, we extend the pairing-based CL-anonymous credential system and present a series of attributes proof protocols. They enable users to prove to relying parties the AND and OR relations over multiple attributes, as well as equality to a given value and lying into a given interval over some single attribute
Experimental Study of Diffusion and Formation Mineral Change in Supercritical CO2 Huff and Puff Process of Shale Reservoir
AbstractIn order to understand the diffusion during CO2 huff and puff in the development of shale oil and its influence on the formation, expansion and viscosity reduction experiments of shale oil-CO2 system, CO2 extraction experiments, and CO2 huff and puff physical simulation experiments were conducted. The diffusion characteristics of CO2 during huff and puff and their effects on formation minerals were studied by chromatographic analysis and X-ray diffraction analysis of artificially fractured natural cores. Research indicates that CO2 huff and puff technology is an effective method to enhance the recovery of shale reservoirs after fracturing. By injecting CO2, the light components of shale oil can be effectively extracted; when the amount of injected CO2 is 50%, the saturation pressure of shale oil increases to 27.72 MPa, and the expansion coefficient increases by 27.9%, the viscosity reduction rate of shale oil can reach 58.97%, and the density reduction rate is 10.02%; under the soaking well pressure of 50 MPa, when 0.5PVCO2 was injected and the well stuffed for 8 hours, the CO2 was fully dissolved in the shale oil, and the continuous increase of the injection slug had a little effect on the CO2 diffusion. During the CO2 huff and puff process, CO2 would dissolve in the formation water and fracturing fluid and reacts with dolomite in the reservoir rock, consuming a large amount of dolomite in the reservoir, and the dolomite mineral content of core sample decreased from 30.1% to 2.6%
Biomimetic nanotherapies: red blood cell based core-shell structured nanocomplexes for atherosclerosis management
Cardiovascular disease is the leading cause of mortality worldwide. Atherosclerosis, one of the most common forms of the disease, is characterized by a gradual formation of atherosclerotic plaque, hardening, and narrowing of the arteries. Nanomaterials can serve as powerful delivery platforms for atherosclerosis treatment. However, their therapeutic efficacy is substantially limited in vivo due to nonspecific clearance by the mononuclear phagocytic system. In order to address this limitation, rapamycin (RAP)‐loaded poly(lactic‐co‐glycolic acid) (PLGA) nanoparticles are cloaked with the cell membrane of red blood cells (RBCs), creating superior nanocomplexes with a highly complex functionalized bio‐interface. The resulting biomimetic nanocomplexes exhibit a well‐defined “core–shell” structure with favorable hydrodynamic size and negative surface charge. More importantly, the biomimetic nature of the RBC interface results in less macrophage‐mediated phagocytosis in the blood and enhanced accumulation of nanoparticles in the established atherosclerotic plaques, thereby achieving targeted drug release. The biomimetic nanocomplexes significantly attenuate the progression of atherosclerosis. Additionally, the biomimetic nanotherapy approach also displays favorable safety properties. Overall, this study demonstrates the therapeutic advantages of biomimetic nanotherapy for atherosclerosis treatment, which holds considerable promise as a new generation of drug delivery system for safe and efficient management of atherosclerosis
Interplay of Structural Chirality, Electron Spin and Topological Orbital in Chiral Molecular Spin Valves
Chirality has been a property of central importance in chemistry and biology
for more than a century, and is now taking on increasing relevance in condensed
matter physics. Recently, electrons were found to become spin polarized after
transmitting through chiral molecules, crystals, and their hybrids. This
phenomenon, called chirality-induced spin selectivity (CISS), presents broad
application potentials and far-reaching fundamental implications involving
intricate interplays among structural chirality, topological states, and
electronic spin and orbitals. However, the microscopic picture of how chiral
geometry influences electronic spin remains elusive. In this work, via a direct
comparison of magnetoconductance (MC) measurements on magnetic
semiconductor-based chiral molecular spin valves with normal metal electrodes
of contrasting strengths of spin-orbit coupling (SOC), we unambiguously
identified the origin of the SOC, a necessity for the CISS effect, given the
negligible SOC in organic molecules. The experiments revealed that a
heavy-metal electrode provides SOC to convert the orbital polarization induced
by the chiral molecular structure to spin polarization. Our results evidence
the essential role of SOC in the metal electrode for engendering the CISS spin
valve effect. A tunneling model with a magnetochiral modulation of the
potential barrier is shown to quantitatively account for the unusual transport
behavior. This work hence produces critical new insights on the microscopic
mechanism of CISS, and more broadly, reveals a fundamental relation between
structure chirality, electron spin, and orbital
Highly robust model of transcription regulator activity predicts breast cancer overall survival
Background: While several multigene signatures are available for predicting breast cancer prognosis, particularly in early stage disease, effective molecular indicators are needed, especially for triple-negative carcinomas, to improve treatments and predict diagnostic outcomes. The objective of this study was to identify transcriptional regulatory networks to better understand mechanisms giving rise to breast cancer development and to incorporate this information into a model for predicting clinical outcomes.
Methods: Gene expression profiles from 1097 breast cancer patients were retrieved from The Cancer Genome Atlas (TCGA). Breast cancer-specific transcription regulatory information was identified by considering the binding site information from ENCODE and the top co-expressed targets in TCGA using a nonlinear approach. We then used this information to predict breast cancer patient survival outcome.
Result: We built a multiple regulator-based prediction model for breast cancer. This model was validated in more than 5000 breast cancer patients from the Gene Expression Omnibus (GEO) databases. We demonstrated our regulator model was significantly associated with clinical stage and that cell cycle and DNA replication related pathways were significantly enriched in high regulator risk patients.
Conclusion: Our findings demonstrate that transcriptional regulator activities can predict patient survival. This finding provides additional biological insights into the mechanisms of breast cancer progression
Irreversible transformation of ferromagnetic ordered stripe domains in single-shot IR pump - resonant X-ray scattering probe experiments
The evolution of a magnetic domain structure upon excitation by an intense,
femtosecond Infra-Red (IR) laser pulse has been investigated using single-shot
based time-resolved resonant X-ray scattering at the X-ray Free Electron laser
LCLS. A well-ordered stripe domain pattern as present in a thin CoPd alloy film
has been used as prototype magnetic domain structure for this study. The
fluence of the IR laser pump pulse was sufficient to lead to an almost complete
quenching of the magnetization within the ultrafast demagnetization process
taking place within the first few hundreds of femtoseconds following the IR
laser pump pulse excitation. On longer time scales this excitation gave rise to
subsequent irreversible transformations of the magnetic domain structure. Under
our specific experimental conditions, it took about 2 nanoseconds before the
magnetization started to recover. After about 5 nanoseconds the previously
ordered stripe domain structure had evolved into a disordered labyrinth domain
structure. Surprisingly, we observe after about 7 nanoseconds the occurrence of
a partially ordered stripe domain structure reoriented into a novel direction.
It is this domain structure in which the sample's magnetization stabilizes as
revealed by scattering patterns recorded long after the initial pump-probe
cycle. Using micro-magnetic simulations we can explain this observation based
on changes of the magnetic anisotropy going along with heat dissipation in the
film.Comment: 16 pages, 6 figure
- …