Highly reactive metastable intermixed composites (MICs) have attracted much attention in the past decades. The MIC family of materials mainly includes traditional metal‐based nanothermites, novel ...core–shell‐structured, 3D ordered macroporous‐structured, and ternary nanocomposites. By applying special fabrication approaches, highly reactive MICs with uniformly dispersed reactants, “layer‐by‐layer” or “core–shell” structures, can be prepared. Thus, the combustion performance can be greatly improved, and the ignition characteristics and safety can be precisely controlled by using a certain preparation strategy. Here, the preparation and characterization of the MICs that have been developed during the past few decades are summarized. Traditional preparation methods for MICs generally include physical mixing, high‐energy ball milling, sol–gel synthesis, and vapor deposition, while the novel methods include self‐assembly, electrophoretic deposition, and electrospinning. Various preparation procedures and the ignition and combustion performance of different MIC reactive systems are compared and discussed. In particular, the advantages of novel structured MICs in terms of safety and combustion efficiency are clarified, based on which suggestions regarding the possible future research directions are proposed.
Highly reactive metastable intermixed composites (MICs) prepared by different strategies show various characteristics and properties. By applying special fabrication approaches, highly reactive MICs with uniformly dispersed reactants, assembled in either layer‐by‐layer or core–shell structure, can be prepared. Thus, the improved and desired performances can be achieved by using a certain preparation strategy.
Lanthanide-based upconversion nanomaterials have recently attracted considerable attention in both fundamental research and various frontier applications owing to their excellent photon upconversion ...performance and favourable physicochemical properties. In particular, the emergence of multi-layer core-shell (MLCS) nanostructures offers a versatile and powerful tool to realize well-defined matrix compositions and spatial distributions of the dopant on the nanometer length scale. In contrast to the conventional nanomaterials and commonly investigated core-shell nanoparticles, the rational design of MLCS nanostructures allows us to deliberately introduce more functional properties into an upconversion system, thus providing unprecedented opportunities for the precise manipulation of energy transfer channels, the dynamic control of upconversion processes, the fine tuning of switchable emission colours and new functional integration at a single-particle level. In this review, we present a summary and discussion on the key aspects of the recent progress in lanthanide-based MLCS nanoparticles, including the manipulation of emission and lifetime, the switchable multicolour output and the lanthanide ionic interactions on the nanoscale. Benefitting from the multifunctional and versatile luminescence properties, the MLCS nanostructures exhibit great potential in diversities of frontier applications such as three-dimensional display, upconversion laser, optical memory, anti-counterfeiting, thermometry, bioimaging, and therapy. The outlook and challenges as well as perspectives for the research in MLCS nanostructure materials are also provided. This review would be greatly helpful in exploring new structural designs of lanthanide-based materials to further manipulate the upconversion phenomenon and expand their application boundaries.
Abstract
Induced fit and conformational selection are two dominant binding mechanisms in biology. Although induced fit has been widely accepted by supramolecular chemists, conformational selection is ...rarely studied with synthetic systems. In the present research, we report a macrocyclic host whose binding mechanism is unambiguously assigned to conformational selection. The kinetic and thermodynamic aspects of this system are studied in great detail. It reveals that the kinetic equation commonly used for conformational selection is strictly followed here. In addition, two mathematical models are developed to determine the association constants of the same guest to the two host conformations. A “conformational selectivity factor” is defined to quantify the fidelity of conformational selection. Many details about the kinetic and thermodynamic aspects of conformational selection are revealed by this synthetic system. The conclusion and the mathematical models reported here should be helpful in understanding complex molecular recognition in both biological and synthetic systems.
Epithelial-to-mesenchymal transition (EMT) is a complex process involving multiple genes, steps and stages. It refers to the disruption of tight intercellular junctions among epithelial cells under ...specific conditions, resulting in loss of the original polarity, order and consistency of the cells. Following EMT, the cells show interstitial cell characteristics with the capacity for adhesion and migration, while apoptosis is inhibited. This process is critically involved in embryogenesis, wound-healing, tumor invasion and metastasis. The tumor microenvironment is composed of infiltrating inflammatory cells, stromal cells and the active medium secreted by interstitial cells. Most patients with hepatocellular carcinoma (HCC) have a history of hepatitis virus infection. In such cases, major components of the tumor microenvironment include inflammatory cells, inflammatory factors and virus-encoded protein are major components. Here, we review the relationship between EMT and the inflammatory tumor microenvironment in the context of HCC. We also further elaborate the significant influence of infiltrating inflammatory cells and inflammatory mediators as well as the products expressed by the infecting virus in the tumor microenvironment on the EMT process.
Chemotherapy represents an important treatment option for colorectal cancer (CRC), but only half of the patients benefit from these regimens. We explored the potential predicting value and mechanism ...of PIK3CA mutation in CRC chemotherapy. CRC specimens from 440 patients were retrospectively collected and examined with a fluorescence PCR-based method. The correlation of first-line chemotherapy response and PIK3CA mutation was evaluated according to follow-up and medical records. The underlying mechanism of PIK3CA mutation in chemotherapy resistance was assessed with CRC tumors and primary cells. The mutation frequency of the PIK3CA gene in CRC patients was 9.55%, which was correlated with late TNM staging and lower histological grade. The CRC patients with PIK3A mutation showed worse response to first-line chemotherapy than those without PIK3CA mutation. PIK3A mutation tumor cells showed poor sensitivity to first-line chemotherapy in vitro and in vivo. PIK3CA mutation induced PI3K/Akt signaling activation to increase LGR5
CRC stem cells survival and proliferation, from which lead to chemotherapy resistance. Furthermore, PIK3CA
/LGR5
expression was an independent detrimental factor for CRC patients. Our findings indicated that PIK3CA mutation induced PI3K/Akt activation contributed to CRC stem cells survival and proliferation, from which cells further resistance to chemotherapy. PIK3CA
/LGR5
expression was a potential biomarker for monitoring chemotherapy resistance in CRC.
As a global health threat, NASH has been confirmed to be a chronic progressive liver disease that is strongly associated with obesity. However, no approved drugs or efficient therapeutic strategies ...are valid, mainly because its complicated pathological processes is underestimated.
We identified the RING-type E3 ubiquitin transferase-tripartite motif-containing protein 31 (TRIM31), a member of the E3 ubiquitin ligases family, as an efficient endogenous inhibitor of transforming growth factor-beta-activated kinase 1 (mitogen-activated protein kinase kinase kinase 7; MAP3K7), and we further confirmed that TRIM31 is an MAP3K7-interacting protein and promotes MAP3K7 degradation by enhancing ubiquitination of K48 linkage in hepatocytes. Hepatocyte-specific Trim31 deletion blocks hepatic metabolism homeostasis, concomitant with glucose metabolic syndrome, lipid accumulation, up-regulated inflammation, and dramatically facilitates NASH progression. Inversely, transgenic overexpression, lentivirus, or adeno-associated virus-mediated Trim31 gene therapy restrain NASH in three dietary mice models. Mechanistically, in response to metabolic insults, TRIM31 interacts with MAP3K7 and conjugates K48-linked ubiquitination chains to promote MAP3K7 degradation, thus blocking MAP3K7 abundance and its downstream signaling cascade activation in hepatocytes.
TRIM31 may serve as a promising therapeutic target for NASH treatment and associated metabolic disorders.
A novel mechanistic strategy for probing the energy migration through constructing the interfacial energy transfer (IET) in a core–shell–shell nanostructure is reported. In this design, the trilayer ...nanostructure is composed of a sensitizing core, a migratory interlayer, and a detective shell layer that interact with each other only by IET and the latter two shell layers are nonresponsive to the incident irradiation. This model is well applied in investigating the energy migration over the Tb, Gd, and Yb sublattices, and the results show that the Gd sublattice holds the best energy migratory performance. Moreover, the finding of energy migration over the Yb sublattice enables the 808 nm excited long‐lived upconversion of Tb3+ and Eu3+, which exhibits unique time‐gating performance for information security. The results provide a facile and powerful nanosized model for an in‐depth understanding of the fundamentals involving lanthanide interactions, which will further help excite new chances for the frontier applications of lanthanide‐based luminescent materials.
Probing energy migration among a set of lanthanides is realized by constructing an interfacial energy‐transfer‐mediated trilayer nanostructure. The results provide a facile and powerful nanosized model for an in‐depth understanding of the fundamentals involving energy migration of lanthanides, which will also excite new chances for developing new class of upconversion materials toward frontier applications.
With more than 600,000 mortalities each year, colorectal cancer (CRC) is the third most commonly diagnosed type of cancer worldwide. Recently, mechanisms involving noncoding RNAs have been implicated ...in the development of CRC.
We examined expression levels of lncRNA CRNDE and miR-181a-5p in 64 cases of CRC tissues and cell lines by qRT-PCR. Gain-of-function and loss-of-function assays were performed to examine the effect of CRNDE and miR-181a-5p on proliferation and chemoresistance of CRC cells. Using fluorescence reporter and western blot assays, we also explored the possible mechanisms of CRNDE in CRC cells.
In this study, we found that the expression levels of the CRNDE were upregulated in CRC clinical tissue samples. We identified microRNA miR-181a-5p as an inhibitory target of CRNDE. Both CRNDE knockdown and miR-181a-5p overexpression in CRC cell lines led to inhibited cell proliferation and reduced chemoresistance. We also determined that β-catenin and TCF4 were inhibitory targets of miR-181a-5p, and that Wnt/β-catenin signaling was inhibited by both CRNDE knockdown and miR-181a-5p overexpression. Significantly, we found that the repression of cell proliferation, the reduction of chemoresistance, and the inhibition of Wnt/β-catenin signaling induced by CRNDE knockdown would require the increased expression of miR-181a-5p.
Our study demonstrated that the lncRNA CRNDE could regulate the progression and chemoresistance of CRC via modulating the expression levels of miR-181a-5p and the activity of Wnt/β-catenin signaling.
Lanthanide‐based materials exhibit abundant emission colors under suitable infrared excitations; however, the dynamic control of orthogonal photon upconversion of lanthanide ions has remained ...challenging. Here, a novel mechanistic strategy to enable orthogonal upconversion emissions through energy migration in a simple core–shell nanostructure is reported. By constructing the migratory ytterbium‐sublattice shell layer outside the luminescent erbium matrix, the population of erbium emitters at their intermediate energy levels can be finely manipulated, and the red‐to‐green color‐switchable output has been achieved under separate 980 and 808 (or 1530) nm excitations. More interestingly, a tuning of the excitation pulse width also results in a gradual red‐to‐green color change. The mechanistic role of energy migration over ytterbium sublattice is also examined. A conceptual core–shell model for the excitation‐emission orthogonal upconversion output is provided, which is not only important for the fundamental research of photon upconversion but also helps in exciting new chances for the frontier applications such as information security.
A novel simple migratory core–shell conceptual model is developed for orthogonal upconversion. The red‐to‐green switchable output is easily achieved by dynamic control of the upconversion through altering the excitation wavelengths (e.g., 980/1530 nm) or using the non‐steady‐state excitation, showing great promise in multilevel information security.
An FeBr3‐catalyzed reductive coupling of various aldehydes with alkenes that proceeds through a direct hydride transfer pathway has been developed. With iPrOH as the hydrogen donor under mild ...conditions, previously challenging coupling reactions of unactivated alkyl and aryl aldehydes with simple alkenes, such as styrene derivatives and α‐olefins, proceeded smoothly to furnish a diverse range of functionalized alcohols with complete linear regioselectivity.
The reductive coupling of various aldehydes and alkenes through a direct hydride transfer pathway can be catalyzed by FeBr3. With isopropanol as the hydrogen donor, previously challenging coupling reactions of unactivated alkyl and aryl aldehydes with simple alkenes, such as styrene derivatives and α‐olefins, proceeded smoothly to furnish a diverse range of functionalized alcohols with complete linear regioselectivity.
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