Engineering nanomaterials are increasingly considered promising and powerful biomedical tools or devices for imaging, drug delivery, and cancer therapies, but few nanomaterials have been tested in ...clinical trials. This wide gap between bench discoveries and clinical application is mainly due to the limited understanding of the biological identity of nanomaterials. When they are exposed to the human body, nanoparticles inevitably interact with bodily fluids and thereby adsorb hundreds of biomolecules. A “biomolecular corona” forms on the surface of nanomaterials and confers a new biological identity for NPs, which determines the following biological events: cellular uptake, immune response, biodistribution, clearance, and toxicity. A deep and thorough understanding of the biological effects triggered by the protein corona in vivo will speed up their translation to the clinic. To date, nearly all studies have attempted to characterize the components of protein coronas depending on different physiochemical properties of NPs. Herein, recent advances are reviewed in order to better understand the impact of the biological effects of the nanoparticle–corona on nanomedicine applications. The recent development of the impact of protein corona formation on the pharmacokinetics of nanomedicines is also highlighted. Finally, the challenges and opportunities of nanomedicine toward future clinical applications are discussed.
Recent advances toward better understanding the impact of the biological effects of the nanoparticle–corona on nanomedicine applications are summarized. The recent development of the impact of protein corona formation on the pharmacokinetics of nanomedicines is also highlighted. Finally, the challenges and opportunities of nanomedicine toward future clinical applications are discussed.
Quantum mechanics together with general relativity leads to the Károlyházy relation and a corresponding energy density of quantum fluctuations of space–time. Based on the energy density we propose a ...dark energy model, in which the age of the universe is introduced as the length measure. This dark energy is consistent with astronomical data if the unique numerical parameter in the dark energy model is taken to be a number of order one. The dark energy behaves like a cosmological constant at early time and drives the universe to an eternally accelerated expansion with power-law form at late time. In addition, we point out a subtlety in this kind of dark energy model.
Among the multiple components of propolis, flavonoids contribute greatly to the antioxidant activities of propolis. Flavonoids mainly exist in the form of sugar-conjugated derivatives. Quercetin ...glycosides represent the predominant flavonoid fraction in propolis. In this work, density functional theory (DFT) calculations were applied to analyze the antioxidative properties of quercetin and its glucosides in the gas and in the liquid phase (ethanol, water). Three main antioxidant mechanisms, hydrogen atom transfer (HAT), single electron transfer followed by proton transfer (SET-PT) and sequential proton loss electron transfer (SPLET) were used to analyze the antioxidative capacity of the investigated compounds. Solvent effects dominantly affect SET-PT and SPLET. Thus, the thermodynamically preferred mechanism can be altered. HAT and SPLET are the thermodynamically dominant mechanisms in gas and solvent phases, respectively. Therefore, in the gas phase, the sequence of the antioxidative capacity is similar with the bond dissociation enthalpy values: quercetin > quercetin-5-O-glucoside > quercetin-7-O-glucoside > quercetin-3-O-glucoside > quercetin-3'-O-glucoside > quercetin-4'-O-glucoside. While, in the solvent phases, the sequence is similar with the proton affinity values: quercetin-4'-O-glucoside > quercetin-5-O-glucoside > quercetin > quercetin-3-O-glucoside > quercetin-7-O-glucoside > quercetin-3'-O-glucoside. OH groups in B-ring and C-ring contribute mainly to the antioxidative activities of quercetin and glucosides compared with A-ring.
We present exact analytical black hole solutions with conformal anomaly in AdS space and discuss the thermodynamical properties of these black hole solutions. These black holes can have a positive, ...zero and negative constant curvature horizon, respectively. For the black hole with a positive constant curvature horizon, there exists a minimal horizon determined by the coefficient of the trace anomaly, the black hole with a smaller horizon is thermodynamically unstable, while it is stable for the case with a larger horizon. The Hawking–Page transition happens in this case. For the black hole with a Ricci flat horizon, the black hole is always thermodynamically stable and there is no Hawking–Page transition. In the case of the black hole with a negative constant curvature horizon, there exists a critical value for the coefficient of the trace anomaly, under this critical value, the black hole is always thermodynamical stable and the Hawking–Page transition does not happen. When the coefficient is beyond the critical value, the black hole with a smaller horizon is thermodynamically unstable, but it becomes stable for the case with a larger horizon, the Hawking–Page transition always happens in this case. The latter is a new feature for the black holes with a negative constant curvature horizon.
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We establish a no inner-horizon theorem for black holes with charged scalar hairs. Considering a general gravitational theory with a charged scalar field, we prove that there exists no ...inner Cauchy horizon for both spherical and planar black holes with non-trivial scalar hair. The hairy black holes approach to a spacelike singularity at late interior time. This result is independent of the form of scalar potentials as well as the asymptotic boundary of spacetimes. We prove that the geometry near the singularity takes a universal Kasner form when the kinetic term of the scalar hair dominates, while novel behaviors different from the Kasner form are uncovered when the scalar potential become important to the background. For the hyperbolic horizon case, we show that hairy black hole can only has at most one inner horizon, and a concrete example with an inner horizon is presented. All these features are also valid for the Einstein gravity coupled with neutral scalars.
Circular RNAs (CircRNAs) are single-stranded, covalently closed RNA molecules that are ubiquitous across species ranging from viruses to mammals. Important advances have been made in the biogenesis, ...regulation, localization, degradation and modification of circRNAs. CircRNAs exert biological functions by acting as transcriptional regulators, microRNA (miR) sponges and protein templates. Moreover, emerging evidence has revealed that a group of circRNAs can serve as protein decoys, scaffolds and recruiters. However, the existing research on circRNA-protein interactions is quite limited. Hence, in this review, we briefly summarize recent progress in the metabolism and functions of circRNAs and elaborately discuss the patterns of circRNA-protein interactions, including altering interactions between proteins, tethering or sequestering proteins, recruiting proteins to chromatin, forming circRNA-protein-mRNA ternary complexes and translocating or redistributing proteins. Many discoveries have revealed that circRNAs have unique expression signatures and play crucial roles in a variety of diseases, enabling them to potentially act as diagnostic biomarkers and therapeutic targets. This review systematically evaluates the roles and mechanisms of circRNAs, with the hope of advancing translational medicine involving circRNAs.
We develop a formalism to calculate the merger rate density of primordial black hole binaries with a general mass function, by taking into account the merger history of primordial black holes. We ...apply the formalism to three specific mass functions: the monochromatic, power-law and log-normal cases. In the former case, the merger rate density is dominated by the single-merger events, while in the latter two cases, the contribution of the multiple-merger events on the merger rate density cannot be ignored. The effects of the merger history on the merger rate density depend on the mass function.
In this note, we propose a new model of agegraphic dark energy based on the Károlyházy relation, where the time scale is chosen to be the conformal time η of the Friedmann–Robertson–Walker (FRW) ...universe. We find that in the radiation-dominated epoch, the equation-of-state parameter of the new agegraphic dark energy wq=−1/3 whereas Ωq=n2a2; in the matter-dominated epoch, wq=−2/3 whereas Ωq=n2a2/4; eventually, the new agegraphic dark energy dominates; in the late time wq→−1 when a→∞, and the new agegraphic dark energy mimics a cosmological constant. In every stage, all things are consistent. The confusion in the original agegraphic dark energy model proposed in R.G. Cai, Phys. Lett. B 657 (2007) 228, arXiv: 0707.4049 hep-th disappears in this new model. Furthermore, Ωq≪1 is naturally satisfied in both radiation-dominated and matter-dominated epochs where a≪1. In addition, we further extend the new agegraphic dark energy model by including the interaction between the new agegraphic dark energy and background matter. In this case, we find that wq can cross the phantom divide.
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