Lanthanide ion (Ln(3+))-based upconversion nano/micromaterials that emit higher-energy visible light when excited by low-energy NIR light have aroused considerable attention in the forefront of ...materials science and biomedical fields, which stems from their unique optical and chemical properties including minimum photodamage to living organisms, low autofluorescence, high signal-to-noise ratio and detection sensitivity, and high penetration depth in biological or environmental samples. Thus, Ln(3+)-based upconversion materials are rising new stars and are quickly emerging as potential candidates to revolutionize novel biomedical applications. In this review article, we mainly focus on the recent progress in various chemical syntheses of Ln(3+)-based upconversion nanomaterials, with special emphasis on their application in stimuli-response controlled drug release and subsequent therapy. Functional groups that are introduced into the stimuli-responsive system can respond to external triggers, such as pH, temperature, light, and even magnetic fields, which can regulate the movement of the pharmaceutical cargo and release the drug at a desired time and in a desired area. This is crucial to boost drug efficacy in cancer treatment while minimizing the side effects of cytotoxic drugs. Many multifunctional (magnetic/upconversion luminescence and porous) composite materials based on Ln(3+) have been designed for controlled drug delivery and multimodal bioimaging. Finally, the challenges and future opportunities for Ln(3+)-based upconversion materials are discussed.
•The LBL electrostatic deposition maintained strawberry firmness and volatile aroma.•The LBL coating inhibited some primary metabolism in strawberry.•Special secondary metabolites in LBL coated ...strawberry were reduced after storage.
Postharvest strawberries (Fragaria × ananassa Duch.) were coated either by the layer-by-layer (LBL) electrostatic deposition, based on chitosan and carboxymethyl cellulose (CMC), or coated by 1% chitosan. Results suggested that LBL edible coating was significantly effective at inhibiting the loss of fruit firmness and aroma volatiles of strawberry, with little effect on the total soluble solids and total acidity contents. Through an untargeted metabolomic analysis, we found that the LBL application significantly reduced the primary metabolite contents involved in carbohydrate, fatty acids and amino acids metabolism, as well as the secondary metabolite contents involved in terpenoid, carotenoid, phenylpropanoid and flavonoid metabolism after storage. Our results indicated that the LBL edible coating could be potential to maintain strawberry quality with lower metabolites contents after eight days of storage.
Controlling anticancer drug activity and release on demand is very significant in cancer therapy. The photoactivated platinum(IV) pro-drug is stable in the dark and can be activated by UV light. In ...this study, we develop a multifunctional drug delivery system combining upconversion luminescence/magnetic resonance/computer tomography trimodality imaging and NIR-activated platinum pro-drug delivery. We use the core–shell structured upconversion nanoparticles to convert the absorbed NIR light into UV to activate the trans-platinum(IV) pro-drug, trans,trans,trans-Pt(N3)2(NH3)(py)(O2CCH2CH2COOH)2. Compared with using the UV directly, the NIR has a higher tissue penetration depth and is less harmful to health. Meanwhile, the upconversion nanoparticles can effectively deliver the platinum(IV) pro-drugs into the cells by endocytosis. The mice treated with pro-drug-conjugated nanoparticles under near-infrared (NIR) irradiation demonstrated better inhibition of tumor growth than that under direct UV irradiation. This multifunctional nanocomposite could be used as multimodality bioimaging contrast agents and transducers by converting NIR light into UV for control of drug activity in practical cancer therapy.
The 7 years electron density data observed by the Swarm constellation and 527 earthquakes with M ≥ 6.0 are used to investigate the relationship between ionospheric disturbances and seismic events. ...The disturbances of the ionospheric electron density, defined as the difference between the orbital observation data and its fitting data, are considered to be possible signals of the seismic activity and are often reported before or after earthquakes near the epicenter. To investigate the relationship between them, the spatial distribution characteristics of the disturbances are analysed, taking into account the influence of solar and geomagnetic activity on the disturbances; the variation characteristics of the disturbances in seismic and non-seismic regions are compared; the numbers of the disturbances before and after earthquakes are statistically analysed; and the statistical results of different earthquake groups are verified by comparison with random events. Finally, according to these analysis results, it can be concluded that most of the disturbances are related to ionospheric activities; some of disturbances are indeed related to seismic activity; the disturbances caused by seismic activities usually appear before the earthquakes. In terms of standardized probability, the results for M ≥ 6 earthquakes and sea earthquakes are most significant, exceeding two times the standard deviation at least 10 and 25 days before the earthquake, while the results for deep earthquakes (D ≥ 60 km) and land earthquakes are not significant. However, the disturbances caused by seismic activities are very weak and are hidden in those strong ionospheric activities. Therefore, the seismic ionospheric phenomena are so difficult to extract and identify, and more caution should be taken in the identification in future seismo-ionospheric phenomena research.
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•Seven years of Ne data and 527 earthquakes with M ≥6.0 are used to investigate Seismo-ionospheric phenomenon.•The number of disturbance before earthquake is greater than that after earthquake under the same conditions.•The percentage of disturbances before earthquake is greater than the one obtained by random events.•The standardized probabilities of disturbances show a peak about 10 days before the earthquake.•The rapid disturbances are related to the seismic-ionospheric interaction.
Amino acid metabolism could exert regulatory effects on
Monascus
pigments (MPs) biosynthesis. In this work, MPs biosynthesis regulated by methionine and S-adenosylmethionine (SAM) was investigated in
...Monascus purpureus
RP2. The results indicated that the addition of methionine in fermentation significantly reduced MPs production by 60–70%, and it induced a higher expression of SAM synthetase Mon2A2272 and consequently led to SAM accumulation. However, the addition of SAM in fermentation promoted MPs production by a maximum of 35%, while over-expression of the gene
Mon2A2272
led to a decrease in MPs yield, suggesting that SAM synthetase and SAM were likely to play different regulatory roles in MPs biosynthesis. Furthermore, the gene transcription profile indicated that SAM synthetase expression led to a higher expression of the transcriptional regulatory protein of the MPs biosynthesis gene cluster, while the addition of SAM gave rise to a higher expression of MPs biosynthesis activator and the global regulator LaeA, which probably accounted for changes in MPs production and the mycelium colony morphology of
M. purpureus
RP2 triggered by methionine and SAM. This work proposed a possible regulation mechanism of MPs biosynthesis by SAM metabolism from methionine. The findings provided a new perspective for a deep understanding of MPs biosynthesis regulation in
M. purpureus.
This letter studies the secrecy performance for a two‐way integrated satellite terrestrial relay networks. Particularly, multiple legitimate users along with maximal user scheduling scheme are ...applied in the considered networks. In addition, the closed‐form expression for the secrecy outage probability of the considered two‐way networks is obtained. Moreover, to investigate the impacts of the system parameters on the secrecy performance in high signal‐to‐noise ratio regime, the asymptotic analysis for the secrecy outage probability is further derived. Finally, Monte Carlo simulation results are provided to prove the theoretical results.
Background
Accurate delineation of cancer margins is critical for endoscopic curative resection. This study aimed to train and validate real-time fully convolutional networks for delineating the ...resection margin of early gastric cancer (EGC) under indigo carmine chromoendoscopy (CE) or white light endoscopy (WLE), and evaluated its performance and that of magnifying endoscopy with narrow-band imaging (ME-NBI).
Methods
We collected CE and WLE images of EGC lesions to train fully convolutional networks ENDOANGEL. ENDOANGEL was tested both on stationary images and endoscopic submucosal dissection (ESD) videos. The accuracy and reliability of ENDOANGEL and NBI-dependent delineation were further evaluated by a novel endoscopy–pathology point-to-point marking.
Results
ENDOANGEL had an accuracy of 85.7% in the CE images and 88.9% in the WLE images under an overlap ratio threshold of 0.60 in comparison with the manual markers labeled by the experts. In the ESD videos, the resection margins predicted by ENDOANGEL covered all areas of high-grade intraepithelial neoplasia and cancers. The minimum distance between the margins predicted by ENDOANGEL and the histological cancer boundary was 3.44 ± 1.45 mm which outperformed the resection margin based on ME-NBI.
Conclusions
ENDOANGEL has the potential to assist endoscopists in delineating the resection extent of EGC under CE or WLE during ESD.
In this study, we report a new controlled release system based on up-conversion luminescent microspheres of NaYF4:Yb3+/Er3+ coated with the smart hydrogel poly(N-isopropylacrylamide)-co-(methacrylic ...acid) (P(NIPAM-co-MAA)) (prepared using 5 mol % of MAA) shell. The hybrid microspheres show bright up-conversion fluorescence under 980 nm laser excitation, and turbidity measurements show that the low critical solution temperature of the polymer shell is thermo- and pH-dependent. We have exploited the hybrid microspheres as carriers for Doxorubicin hydrochloride (DOX) due to its stimuli-responsive property as well as good biocompatibility via MTT assay. It is found that the drug release behavior is pH-triggered thermally sensitive. Changing the pH to mildly acidic condition at physiological temperature deforms the structure of the shell, causing the release of a large number of DOX from the microspheres. The drug-loaded microspheres exhibit an obvious cytotoxic effect on SKOV3 ovarian cancer cells. The endocytosis process of drug-loaded microspheres is observed using confocal laser scanning microscopy and up-conversion luminescence microscopy. Meanwhile, the as-prepared NaYF4:Yb3+/Er3+@SiO2@P(NIPAM-co-MAA) microspheres can be used as a luminescent probe for cell imaging. In addition, the extent of drug release can be monitored by the change of up-conversion emission intensity. These pH-induced thermally controlled drug release systems have potential to be used for in vivo bioimaging and cancer therapy by the pH of the microenvironment changing from 7.4 (normal physiological environment) to acidic microenvironments (such as endosome and lysosome compartments) owing to endocytosis.
Based on the survey data of 1707 high-quality farmers in Guangdong and Jiangxi provinces in China, this article uses the DEA-tobit model and propensity score matching method to explore the impact of ...water-saving technology adoption on agricultural production efficiency from a micro perspective. The research results show that the adoption of water-saving technology by high-quality farmers can significantly improve agricultural production efficiency. By comparing the results with the baseline regression using propensity score matching method, the study findings are found to be robust. The mechanism and results of the study indicate that agricultural subsidy policies play a regulatory role between water-saving technology adoption and the agricultural production efficiency of high-quality farmers. Further analysis reveals that the impact of water-saving technology on the production efficiency of different types of high-quality farmers varies. Specifically, water-saving technology has a greater impact on the production efficiency of farmer cooperatives and agricultural enterprises compared to large-scale farming households and family farms. Therefore, policy recommendations are proposed to improve the water-saving agricultural technology system, among other aspects.
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