Phase‐change materials (PCMs) have emerged as a novel class of thermo‐responsive materials for controlled release, where the payloads encapsulated in a solid matrix are released only upon melting the ...PCM to trigger a solid‐to‐liquid phase transition. Herein, the advances over the past 10 years in utilizing PCMs as a versatile platform for the encapsulation and release of various types of therapeutic agents and biological effectors are highlighted. A brief introduction to PCMs in the context of desired properties for controlled release and related applications is provided. Among the various types of PCMs, a specific focus is placed on fatty acids and fatty alcohols for their natural availability, low toxicity, biodegradability, diversity, high abundance, and low cost. Then, various methods capable of processing PCMs, and their mixtures with payloads, into stable suspensions of colloidal particles, and the different means for triggering the solid‐to‐liquid phase transition are discussed. Finally, a range of applications enabled by the controlled release system based on PCMs are presented together with some perspectives on future directions.
Phase‐change materials feature drastic increase in molecular mobility upon melting. Leveraging this attribute, they are actively explored as a novel class of thermoresponsive materials for the encapsulation and release of various types of payloads, including anticancer drugs, inorganic ions, reactive species, biomacromolecules, and even functional nanoparticles, in a controllable manner.
This study investigates the stress-dependency of relative permeability in rock fractures. Previous studies provide contradictory evidence of the influence of increasing stress on the relative ...permeability of fractures. Some studies suggest that irreducible water saturation increases, while others show the reverse. In an attempt to resolve these differences, laboratory core flooding experiments are applied to measure the relative permeability of nitrogen–water mixtures in a fracture under various states of effective stress. Simultaneous X-ray CT measurements are made of aperture and water saturation distributions in the fracture. Two effective stress levels, 2.07 and 5.52 MPa, are applied to investigate the stress-dependency. For both states of stress, the measurements show that the relative permeability to gas is very low until a critical saturation is reached. As gas saturation increases beyond the critical value, relative permeability to gas increases quickly while water becomes essentially immobile. Results also demonstrate that increasing stress lowers the irreducible water saturation and the end-point non-wetting phase relative permeability when the experiments are conducted at the same flow rate. Using invasion percolation theory with the fracture aperture maps made at the two different effective stresses, capillary pressure curves are calculated and used to explain changes in phase interference at different stress levels. Finally, the preferential flow paths are analyzed at both stress levels. We use this analysis to reconcile flow regimes observed in earlier studies, and conclude that the differences between them can be explained by the relative importance of viscous and capillary forces. Specifically, if the experiments are designed to keep the capillary number constant, the irreducible water saturation increases with increasing confining stress. If the experiments are conducted at the same flow rate, higher confining stress decreases the irreducible water saturation, as was observed in these experiments. The analysis and data presented here also suggest that small increases in the water saturation of a fracture may dramatically reduce gas flow rates. This may present an additional and unexplored explanation for rapid production decline of gas wells in fractured reservoirs.
Anticancer modalities based on oxygen free radicals, including photodynamic therapy and radiotherapy, have emerged as promising treatments in the clinic. However, the hypoxic environment in tumor ...tissue prevents the formation of oxygen free radicals. Here we introduce a novel strategy that employs oxygen‐independent free radicals generated from a polymerization initiator for eradicating cancer cells. The initiator is mixed with a phase‐change material and loaded into the cavities of gold nanocages. Upon irradiation by a near‐infrared laser, the phase‐change material is melted due to the photothermal effect of gold nanocages, leading to the release and decomposition of the loaded initiator to generate free radicals. The free radicals produced in this way are highly effective in inducing apoptosis in hypoxic cancer cells.
Oxygen‐independent free radicals: Gold nanocages filled with a phase‐change material (green patches in picture) are used as a carrier for the radical source AIPH (blue circles) to achieve controlled generation of free radicals. The process is oxygen‐independent and can be used for the therapy of hypoxic cancer.
How to improve the bonding ability and quality performance of heterogeneous plates has always been one of the difficult problems in the field of high-performance heterogeneous composite sheet forming ...and manufacturing. In this paper, a new manufacturing method of heterogeneous clad plate, hard plate rolling clad plate, is proposed. The hot rolling process of Al/Mg/Al composite slab with or without hard plate was studied. The results show that the shear stress in the rolling direction (RD) can be transformed into the compressive stress in the normal direction (ND), and then the welding pressure between different composite layers can be increased. This method can suppress the bending and edge crack defects and significantly improve the shape quality and forming ability. At the same time, through the study of the interface structure of the composite plate, it can be known that the metallurgical bonding can be achieved with a small reduction after adding the hard plate. Two clear layers of Al
3
Mg
2
and Al
17
Mg
12
intermetallic compounds appear at the Al/Mg interface. The thickness of the diffusion layer is significantly larger than that of the traditional hot-rolled clad plate, and the thickness of the diffusion layer can reach 38 μm when the reduction is 60%. The yield strength is 172.3 MPa and the elongation is 21.5%. To sum up, the hot rolling of hard-plate provides a new idea for the forming and manufacturing of high performance heterogeneous composite plate.
A smart release system responsive to near‐infrared (NIR) light is developed for intracellular drug delivery. The concept is demonstrated by coencapsulating doxorubicin (DOX) (an anticancer drug) and ...IR780 iodide (IR780) (an NIR‐absorbing dye) into nanoparticles made of a eutectic mixture of naturally occurring fatty acids. The eutectic mixture has a well‐defined melting point at 39 °C, and can be used as a biocompatible phase‐change material for NIR‐triggered drug release. The resultant nanoparticles exhibit prominent photothermal effect and quick drug release in response to NIR irradiation. Fluorescence microscopy analysis indicates that the DOX trapped in the nanoparticles can be efficiently released into the cytosol under NIR irradiation, resulting in enhanced anticancer activity. A new platform is thus offered for designing effective intracellular drug‐release systems, holding great promise for future cancer therapy.
A smart system responsive to near‐infrared (NIR) light is developed by coencapsulating a drug and an NIR‐absorbing dye into nanoparticles made of a eutectic mixture of naturally occurring fatty acids. Photothermal heating under NIR irradiation facilitates rapid and efficient intracellular drug release, leading to enhancement in anticancer activity.
The energy hub is a powerful conceptualization of how to acquire, convert, and distribute energy resources in the smart city. However, uncertainties such as intermittent renewable energy injection ...present challenges to energy hub optimization. This paper solves the optimal energy flow of adjacent energy hubs to minimize the energy costs by utilizing the flexibility of energy resources in a smart city with uncertain renewable generation. It innovatively models the power and gas flows between hubs using chance constraints, thus permitting the temporary overloading acceptable on real energy networks. This novelty not only ensures system security but also helps reduce or defer network investment. By restricting the probability of chance constraints over a specific level, the energy hub optimization is formulated as a multiperiod stochastic problem with the total generation cost as the objective. Cornish-Fisher expansion is utilized to incorporate the chance constraints into the optimization, which transforms the stochastic problem into a deterministic problem. The interior-point method is then applied to resolve the developed model. The proposed chance-constrained optimization is demonstrated on a three-hub system and results extensively illustrate the impact of chance constraints on power and gas flows. This work can benefit energy hub operators by maximizing renewable energy penetration at the lowest cost in a smart city.
Myeloid‐derived suppressor cells (MDSCs) are garnering increasing attention given their role in tumor development. Herein, a nano‐enabled strategy is demonstrated for the eradication of ...tumor‐infiltrated MDSCs by reversing hypoxia. Oxygen‐independent photodynamic bismuth tungstate nanoparticles (Bi2WO6 NPs) are loaded into reactive oxygen species (ROS) responsive platelet membranes (PMs) to form a hybrid (PM‐BiW NPs). P‐Selectin on PMs endows PM‐BiW NPs with selectivity toward cancer cells. Once in the tumor, laser illumination stimulates the Bi2WO6 NPs photothermally and photodynamically, which produces enormous quantities of hydroxyl radicals. These hydroxyl radicals help rupture the PM and mitigate hypoxia with the assistance of ionizing radiation. This effectively remodels the tumor microenvironment toward one disfavoring the recruitment of MDSCs and contributes to better prognosis. To better understand the mechanism, the expression levels of a set of markers are monitored. It is found that the downregulations of hypoxia‐inducible factor‐1α, ectonucleoside triphosphate diphosphohydrolase 2, and adenosine‐5‐phosphoricacid are behind the blocked infiltration of MDSCs. This platform strategy offers a promising approach to overcome the immunosuppression caused by MDSCs through a trimodal therapy integrating the power of photothermal and photodynamic therapy in addition to radiation therapy.
The generation of •OH from platelet membranes‐coated bismuth tungstate nanoparticles in the phototherapy treatment effectively alleviates the anabatic tumor hypoxia in radiotherapy (RT) via a radical‐boosted RT sensitivity approach. Subsequently, the frequency of myeloid‐derived suppressor cells detected in tumor tissues dramatically declines, which strikingly promotes T cell recruitment and activation, and improves treatment outcome.
•Plenty of studies on multi-faceted of cyanobacterial blooms have been conducted in China.•Intensity of cyanobacterial blooms in several main lake/river basins has been largely controlled.•Blooms ...caused by alternative bloom-forming cyanobacterial species are largely neglected.
Cyanobacterial blooms, which refer to the massive growth of harmful cyanobacteria, have altered the global freshwater ecosystems during the past decades. China has the largest population in the world, and it is suffering from the harmful effect of water eutrophication and cyanobacterial blooms along with rapid development of the economy and society. Research on cyanobacterial blooms and cyanotoxins in China have been overwhelmingly enhanced and emphasized during the past decades. In the present review, the research on cyanobacterial blooms in China is generally introduced, including the history of cyanobacterial bloom studies, the diversity of the bloom-forming cyanobacteria species (BFCS), and cyanotoxin studies in China. Most studies have focused on Microcystis, its blooms, and microcystins. Newly emerging blooms with the dominance of non-Microcystis BFCS have been gradually expanding to wide regions in China. Understanding the basic features of these non-Microcystis BFCS and their blooms, including their diversity, occurrence, physio-ecology, and harmful metabolites, will provide direction on future studies of cyanobacterial blooms in China.
In this study, two aspects of the ultrastructure of white spot syndrome virus (WSSV) were identified: (i) The virus nucleocapsids were disassembled, and transmission electron microscopy (TEM) image ...analysis confirmed that the nucleocapsids were composed of stacked ring segments rather than the usual helix system, with each ring segment consisting of three rows of subunits linked by filaments. (ii) In addition, the morphological characteristics of virus self-assembly at different stages were observed, and two different enveloping morphologies were found, implying that the virion matures through two distinct envelopments. Thus, we propose a viral membrane assembly process for WSSV virion.
The consumption of oxygen in photodynamic therapy (PDT) significantly exacerbates the degree of hypoxia in tumors, which not only impedes the therapeutic effect of PDT, but also drives local tumor ...recurrence. To relieve the PDT-induced hypoxia and improve the therapeutic outcome of PDT in cancer treatment, herein we reported a class of Bi2WO6 nanoparticles (NPs) as a robust multifunctional platform, which integrates the abilities for contrast-enhanced computed tomography (CT) imaging, photothermal therapy, and PDT in an oxygen-free manner. The as-obtained Bi2WO6 NPs with a mean diameter of 5.2 nm are stable in phosphate-buffered saline and an in vivo microenvironment-mimicking buffer. The location of the solid tumor could be accurately positioned using Bi2WO6-enhanced CT with higher spatial resolution. After being irradiated with an 808 nm laser, these Bi2WO6 NPs could realize CT-guided local photothermal ablation of the tumor. Meanwhile, •OH radicals were generated simultaneously from the treatment without consuming an oxygen molecule, which enabled these Bi2WO6 NPs to exert photodynamic killing effect in an oxygen-free manner during cancer therapy. Remarkable tumor suppression was observed in mice bearing the HeLa xenograft, supporting the promising application of these multifunctional Bi2WO6 NPs in the combat against cancers through synergistic photothermal and oxygen-free PDT treatment.
PDF
