Cancer is a leading public health problem worldwide. Its treatment remains a daunting challenge, although significant progress has been made in existing treatments in recent years. A large concern is ...the poor therapeutic effect due to lack of specificity and low bioavailability. Gene therapy has recently emerged as a powerful tool for cancer therapy. However, delivery methods limit its therapeutic effects. Exosomes, a subset of extracellular vesicles secreted by most cells, have the characteristics of good biocompatibility, low toxicity and immunogenicity, and great designability. In the past decades, as therapeutic carriers and diagnostic markers, they have caught extensive attention. This review introduced the characteristics of exosomes, and focused on their applications as delivery carriers in DNA, messenger RNA (mRNA), microRNA (miRNA), small interfering RNA (siRNA), circular RNA (circRNA) and other nucleic acids. Meanwhile, their application in cancer therapy and exosome-based clinical trials were presented and discussed. Through systematic summarization and analysis, the recent advances and current challenges of exosome-mediated nucleic acid delivery for cancer therapy are introduced, which will provide a theoretical basis for the development of nucleic acid drugs.
•Soil temperature temporal variations are in-phase with heat fluxes 10-cm deeper.•Moisture depression occurs in the seasonally frozen soil.•Spatiotemporal heterogeneity of moisture is stronger than ...that of temperature.•Strong thermohydraulic coupling exists in cold season, but not in warm season.•Zero curtain occurs in both dry and wet soils and varies from region to region.
Frozen soil properties and thermohydraulic processes are still not fully understood due to lack of in-situ measurements, especially in the high altitudes and high latitudes (HAHL). Based on hourly measurements at 10, 40, 80 and 120 cm depths at 21 sites in the west, south and northeast regions of the Tibetan Plateau (TP) during July 2018 - July 2019, we examined soil particles, spatiotemporal variations of soil thermohydraulic processes and their connections with environmental factors to reveal the heterogenous frozen soil properties on the TP. Sand and silt are the dominant soil particles and clay is less than 10% at the sites. Existing and widely used soil products underestimates (significantly overestimates) sand (clay) content on the TP which raises the uncertainty in the thermohydraulic parameters derived from these products. Diurnal soil moisture and temperature variations are seen only above 40 cm, but seasonal variations occur down to 120 cm due to the soil memory effect. Seasonally frozen soil and permafrost soil show different freezing and melting processes. Dry soil features greater soil temperature temporal variability and deeper maximum frozen depth than wet soil. Zero curtain occurs in both dry and wet soil, and displays high (low) frequency but short (long) duration at 10 (80) cm that vary spatially. Moisture depression exists in seasonally frozen soil and is determined by the initial soil moisture and temperature gradient strength. The strong thermohydraulic coupling existed in cold season collapses in warm season. Soil moisture exhibits higher spatiotemporal variability than soil temperature. At daily time scale, the influences of precipitation, wind speed and relative humidity on soil moisture and temperature vary under different climate conditions. These findings fill the knowledge gaps in the soil thermohydraulic processes in the HAHL, and improve the understanding of frozen soil properties and heat-water coupling processes in soil in the HAHL. The study will benefit the Earth system model development and improve the quality of soil temperature and moisture assimilation and remote sensing products in the HAHL.
A secrecy energy efficiency optimization scheme for a multifunctional unmanned aerial vehicle (UAV) assisted mobile edge computing system is proposed to solve the computing power and security issues ...in the Internet-of-Things scenario. The UAV can switch roles between a computing UAV and jamming UAV based on the channel conditions. To ensure the security of the content and the system energy efficiency in the process of offloading computing tasks, the UAV trajectory, uplink transmit power, user scheduling, and offload task are jointly optimized, and an updated-rate assisted block coordinate descent (BCD) algorithm is used. Simulation results show that this scheme efficiently improves the secrecy performance and energy efficiency of the system. Compared with the benchmark scheme, the secrecy energy efficiency of the scheme is improved by 38.5%.
Biotic constraints, including pathogenic fungi, viruses and bacteria, herbivory insects, as well as parasitic nematodes, cause significant yield loss and quality deterioration of crops. The effect of ...conventional management of these biotic constraints is limited. The advances in transgenic technologies provide a direct and directional approach to improve crops for biotic resistance. More than a hundred transgenic events and hundreds of cultivars resistant to herbivory insects, pathogenic viruses, and fungi have been developed by the heterologous expression of exogenous genes and RNAi, authorized for cultivation and market, and resulted in a significant reduction in yield loss and quality deterioration. However, the exploration of transgenic improvement for resistance to bacteria and nematodes by overexpression of endogenous genes and RNAi remains at the testing stage. Recent advances in RNAi and CRISPR/Cas technologies open up possibilities to improve the resistance of crops to pathogenic bacteria and plant parasitic nematodes, as well as other biotic constraints.
Electrocatalytic reactions possess wide application prospects in solving the energy crisis. Recently, the emerging 0D carbon dots (CDs) have become potential candidate materials due to their low ...cost, high conductivity, easy modification, and simple synthesis. CDs‐based composite materials showcase attractive electrocatalytic performances because of the abundant active sites and charge distribution on the material surface. Considering the complicated structure of CDs, it's important to identify the specific catalytic activity source and understand catalytic mechanisms with the aid of theoretical method. In this review, the latest advancements are presented on improving the electrocatalytic activity and stability of CDs‐based composite materials from theoretical perspective. Meanwhile, the opportunity and challenges about developing high‐performance CDs catalysts are also highlighted.
Facing the growing energy crisis, electrocatalytic reactions have made prominent contributions. The emerging carbon dots (CDs) have become attractive electrocatalyst candidates, owing to their high conductivity, easy modification, abundant active sites, and so forth. However, the complex structure renders high performance CDs debatable. It thus seems important to understand the specific property and mechanism from a theoretical view.
In photocatalytic splitting water for hydrogen evolution, narrow light response range and fast electron-hole recombination of g-C3N4 (CN) limit its photocatalytic activity. In this article, the N, S ...co-doped carbon dots (NSCDs) with up-converted property were loaded on CN nanosheets by thermal polymerization to obtain NSCDs/CN composite catalyst. Characterization, electrochemical researches and hydrogen evolution tests suggest that the photocatalytic activity of CN is greatly promoted by the introduction of NSCDs. Under visible and near-infrared irradiation, the hydrogen evolution rate is 5033.1 μmol g−1 h−1 of NSCDs-5/CN, which is 8.3 times higher than that of CN. The performance improvement is mainly attributed to the increased specific surface area, elevated hydrophilic surface, increased light absorption and suppressed carrier recombination of CN after the introduction of NSCDs. This work unveils the mechanism of the hydrogen evolution activity improvement in NSCDs-5/CN, and also offers a new prospect in the design of high-performance CN-based photocatalysts.
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•A novel NSCDs-5/CN photocatalyst was constructed for efficient photocatalytic HER.•Coupling of NSCDs with CN nanosheets further improved carrier separation.•H2 production efficiency is improved by about 8.3 times under Vis-NIR light.•Improved performance may be attributed to the synergistic effect of NSCDs and CN.
Bisphenol A (BPA) is an effective endocrine-disrupting compound (EDC) that causes adverse effects on human health and environment. Therefore, it is indispensable to construct efficacious methods for ...evaluating the level of BPA to enhance the quality of life. In this study, a facile electrochemical sensor based on reduced graphene oxide-silver/poly-l-lysine nanocomposites (RGO-Ag/PLL) modified glassy carbon electrode (GCE) is proposed for the detection of BPA. The synthesized RGO-Ag/PLL nanocomposites displays high electrocatalytic activity towards the electrochemical oxidation of BPA. Differential pulse voltammetry (DPV) is used as an analytical method for the quantitative determination of BPA, and the fabricated electrochemical sensor exhibits a linear response to BPA in the range of 1–80μM with the limit of detection (LOD) of 0.54μM at a signal-to-noise ratio of 3. Additionally, the developed RGO-Ag/PLL/GCE sensor is applied to detect the BPA in drinking water, and obtains satisfactory results.
Ag nanoclusters (AgNCs) have gained widespread applications in recent years due to their excellent antimicrobial efficacy and distinctive molecule-like characteristics. However, concerns about their ...potential effects on environmental and human health have been raised. Despite the fact that abundant research has been carried out to examine the possible ecotoxicology of AgNCs in a variety of living organisms, these studies have mostly concentrated on the toxicology of individual organisms and only a few have attempted to look into the impact of AgNCs across the aquatic food chain. This work evaluated the transcriptome level genotoxicity of AgNCs and their degraded Ag ions in two model species food chains: the aquatic green algae Scenedesmus obliquus and the invertebrate Daphnia magna. Daphnia magna’s digestive system and glycerophospholipid metabolism were hindered after feeding on Ag-containing algae as a result of down-regulation of the crucial gene PLA2G(SPLA2) that codes for secretory phospholipase A2. Our research also showed that the genotoxicity of AgNCs to Daphnia magna was mediated by a synergic interaction between the particulate form of AgNCs and their degraded Ag ions. The current work offers a fresh viewpoint on the mechanisms underlying AgNCs’ harmful effects and the possible ecological concern that metal-based nanoparticles provide to aquatic life.
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Both hereditary and sporadic breast cancer are suggested to develop from a stem cell subcomponent retaining most key stem cell properties but with dysregulation of self-renewal ...pathways, which drives tumorigenic differentiation and cellular heterogeneity. Cancer stem cells (CSCs), characterized by their self-renewal and differentiation potential, have been reported to contribute to chemo-/radio-resistance and tumor initiation and to be the main reason for the failure of current therapies in breast cancer and other CSC-bearing cancers. Thus, CSC-targeted therapies, such as those inducing CSC apoptosis and differentiation, inhibiting CSC self-renewal and division, and targeting the CSC niche to combat CSC activity, are needed and may become an important component of multimodal treatment. To date, the understanding of breast cancer has been extended by advances in CSC biology, providing more accurate prognostic and predictive information upon diagnosis. Recent improvements have enhanced the prospect of targeting breast cancer stem cells (BCSCs), which has shown promise for increasing the breast cancer remission rate. However, targeted therapy for breast cancer remains challenging due to tumor heterogeneity. One major challenge is determining the CSC properties that can be exploited as therapeutic targets. Another challenge is identifying suitable BCSC biomarkers to assess the efficacy of novel BCSC-targeted therapies. This review focuses mainly on the characteristics of BCSCs and the roles of BCSCs in the formation, maintenance and recurrence of breast cancer; self-renewal signaling pathways in BCSCs; the BCSC microenvironment; potential therapeutic targets related to BCSCs; and current therapies and clinical trials targeting BCSCs.
Co(III)-catalyzed highly regio- and stereoselective direct C6 olefination of 2-pyridones with alkynes has been developed with the assistance of chelation. Upon variation of the reaction conditions, ...2-pyridones react well with diaryl alkynes via a C6 olefination/directing group migration pathway to give the tetrasubstituted 6-vinyl-2-pyridones, but the C6–H olefination with terminal alkynes works effectively to afford only the C6-olefinated 2-pyridones. A judicious choice of a solvent and an additive is crucial for catalysis. The protocols feature 100% atom economy, excellent site selectivity, high stereoselectivity, an ample substrate scope, and good compatibility of functional groups. Synthetic applications are demonstrated, and experimental studies and density functional theory calculations are conducted to gain mechanistic insight into the two transformations.
