A pH switchable hydrophilic fluorescent BODIPY sodium disulfonate for Fe3+ multicolor detection: Experimental and DFT studies.

BODIPY-based chemosensors are widely used owing to merits like good selectivity, high fluorescence quantum yield, and excellent optical stability. As such, a pH-switchable hydrophilic fluorescent probe, BODIPY-PY-(SO3Na)2, was developed for detection of Fe3+ ion in aqueous solutions. BODIPY-PY-(SO3Na)2 revealed strong fluorescence intensity and was responsive to pH value in the range of 6.59-1.96. Additionally, BODIPY-PY-(SO3Na)2 showed good selectivity and sensitivity towards Fe3+. A good linear relationship for Fe3+ detection was obtained from 0.0 µM to 50.0 µM with low detecting limit of 6.34 nM at pH 6.59 and 2.36 nM at pH 4.32, respectively. The response to pH and detection of Fe3+ induced obvious multicolor changes. BODIPY-PY-(SO3Na)2 can also be utilized to quantitatively detect Fe3+ in real water sample. Different mechanisms of Fe3+ detection at investigated pH values were unraveled through relativistic density functional theory (DFT) calculations in BODIPY-PY-(SO3Na)2 and experiments of coexisting cations, anions and molecules. These results enabled us to gain a deeper understanding of the interactions between BODIPY-PY-(SO3Na)2 and Fe3+ and provide valuable fundamental information for design of efficient multicolor chemosensors for Fe3+ as well.

MetaGeo: A General Framework for Social User Geolocation Identification With Few-Shot Learning.

Identifying the geolocation of social media users is an important problem in a wide range of applications, spanning from disease outbreaks, emergency detection, local event recommendation, to fake news localization, online marketing planning, and even crime control and prevention. Researchers have attempted to propose various models by combining different sources of information, including text, social relation, and contextual data, which indeed has achieved promising results. However, existing approaches still suffer from certain constraints, such as: 1) a very few samples are available and 2) prediction models are not easy to be generalized for users from new regions-which are challenges that motivate our study. In this article, we propose a general framework for identifying user geolocation-MetaGeo, which is a meta-learning-based approach, learning the prior distribution of the geolocation task in order to quickly adapt the prediction toward users from new locations. Different from typical meta-learning settings that only learn a new concept from few-shot samples, MetaGeo improves the geolocation prediction with conventional settings by ensembling numerous mini-tasks. In addition, MetaGeo incorporates probabilistic inference to alleviate two issues inherent in training with few samples: location uncertainty and task ambiguity. To demonstrate the effectiveness of MetaGeo, we conduct extensive experimental evaluations on three real-world datasets and compare the performance with several state-of-the-art benchmark models. The results demonstrate the superiority of MetaGeo in both the settings where the predicted locations/regions are known or have not been seen during training.

Do Animations Impair Executive Function in Young Children? Effects of Animation Types on the Executive Function of Children Aged Four to Seven Years.

This study used a three (animation types: educational, entertainment, and control groups) × four (age group: four-, five-, six-, and seven-year-olds) between-group experimental design to investigate the short-term effects of animation type and age on each component of children's executive function (EF) (inhibitory control [IC], cognitive flexibility [CF], and working memory [WM]). One hundred twenty-six kindergarten and first-grade elementary school students in a city in Henan Province of China were selected for the experimental study. The results showed that briefly watching animation affected children's EF. Specifically, watching entertainment cartoons weakened children's IC and CF, while cartoons did not affect children's WM. The moderating effect of age in the relationship between animation type and EFs was non-significant. This study suggests that researchers should focus on the uniqueness of each component of EF in children aged four to seven years, and parents should try to limit children's viewing of animation, especially entertainment animation.

Synchronized Efficacy and Mechanism of Alkaline Fertilizer and Biocontrol Fungi for Fusariumoxysporum f. sp. cubense Tropical Race 4.

The purpose of this study was to determine the effect and mechanism of alkaline fertilizer, bio-control fungi, and their synergistic application on control of Fusarium Tr4 incidence. Synchronized use of the alkaline fertilizer and biocontrol fungi eliminates rhizome browning and reduces the incidence rate of banana Fusarium wilt. The incidence of yellow leaves (ratio of yellow leaf to total leaf) and disease index in +Foc Tr4 CF treatment were the same (65%), while incidence of yellow leaves and disease index in +Foc Tr4 AFBCF were 31% and 33%, respectively. Under the stress of Foc Tr4 infection, the synergistic utilization of the alkaline fertilizer and biocontrol fungi would raise the activities of peroxidase, catalase and superoxide dismutase in banana roots. The root activity of banana was also increased. As a result, the banana height and stem diameter increments, shoot and root dry weight, accumulation of N, P and K in banana plants had been increased. The efficacy of the synergistic application of alkaline fertilizer and biocontrol fungi was not only reducing Foc Tr4 pathogen colonization and distribution in banana plants, but also preventing tylosis formation in vascular vessel effectively. Therefore, the normal transport of water and nutrients between underground and aboveground is ensured.

ATRP-based synthesis of a pH-sensitive amphiphilic block polymer and its self-assembled micelles with hollow mesoporous silica as DOX carriers for controlled drug release.

The atom transfer radical polymerization (ATRP)-based synthesis of a pH-sensitive fluorescent polymer (PSDMA-b-POEGMA) was successfully prepared using 3,6-dibromo-isobutyramide acridine (DIA), an initiator with a fluorescent chromophore, to initiate a lipophilic monomer 2-styryl-1,3-dioxan-5-yl methacrylate (SDMA) and a hydrophilic monomer oligo(ethylene glycol) methyl ether (OEGMA), which contained a cinnamic aldehyde acetal structure. With the addition of hollow mesoporous silicon (HMS@C18), the pH-sensitive core-shell nanoparticles (HMS@C18@PSDMA-b-POEGMA) were developed via a self-assembly process as carriers for the anticancer drug doxorubicin (DOX) for drug loading and controlled release. The nanocomposites showed a higher drug loading capacity which was much higher than that observed using common micelles. At the same time, the polymer coated on the surface of the nanoparticles contains the fluorescent segment of an initiator, which can be used for fluorescence contrast of the cells. The nanocomposite carrier selectively inhibits human melanoma cell A375 relative to human normal fibroblasts GM. The in vitro results suggested that a smart pH sensitive nanoparticles drug delivery system was successfully prepared for potential applications in cancer diagnosis and therapy.

Soil nematode community and crop productivity in response to 5-year biochar and manure addition to yellow cinnamon soil.

BACKGROUND: Manure and biochar soil amendments have shown many benefits to soil quality and crop productivity. This study aimed to reveal the effects of biochar and manure applications on soil fertility improvement and crop productivity in yellow cinnamon soil. RESULTS: This study based on a 5-year field experiment. Four treatments were designed, included the control (CK), biochar amendment, manure amendment, and both biochar and manure amendment (BM). The results showed that: after five years, both biochar and manure treatment improved soil structure by increasing soil mean weight diameter (MWD), and soil water and nutrient supply was also increased by increasing the contents of water content, available potassium and available phosphorus. The productivity was also enhanced as wheat yield under the biochar, manure, and BM treatments increased by 3.59-11.32% compared with CK. In addition, biochar and manure treatment increased soil microbial biomass carbon (MBC) by > 15%, and soil total nematode abundance was significantly increased. Furthermore, the nematode community structure was significantly affected by biochar and manure treatment, dominant trophic group in CK was herbivores, but bacterivores were dominant in the biochar and manure treatments. The distribution of nematode genera was closely related to soil chemical properties and microbial biomass. Increases in the Shannon's diversity index, and decreases in the dominance index and summed maturity index after the 5-year treatment indicated a sustainable soil ecosystem after the biochar and manure applications. CONCLUSIONS: These findings indicate that biochar and manure result in better soil quality and increased productivity in yellow cinnamon soil.

Optofluidic in-fiber interferometer based on hollow optical fiber with two cores.

We demonstrate a novel integrated optical fiber interferometer for in-fiber optofluidic detection. It is composed of a specially designed hollow optical fiber with a micro-channel and two cores. One core on the inner surface of the micro-channel is served as sensing arm and the other core in the annular cladding is served as reference arm. Fusion-and-tapering method is employed to couple light from a single mode fiber to the hollow optical fiber in this device. Sampling is realized by side opening a microhole on the surface of the hollow optical fiber. Under differential pressure between the end of the hollow fiber and the microhole, the liquids can form steady microflows in the micro-channel. Simultaneously, the interference spectrum of the interferometer device shifts with the variation of the concentration of the microfluid in the channel. The optofluidic in-fiber interferometer has a sensitivity of refractive index around 2508 nm/RIU for NaCl. For medicine concentration detection, its sensitivity is 0.076 nm/mmolL-1 for ascorbic acid. Significantly, this work presents a compact microfluidic in-fiber interferometer with a micro-channel which can be integrated with chip devices without spatial optical coupling and without complex manufacturing procedure of the waveguide on the chips.

Synthesis of a novel ionic liquid modified copolymer hydrogel and its rapid removal of Cr (VI) from aqueous solution.

A novel ionic liquid modified copolymer hydrogel (PAMDA) was successfully synthesized by a simple water solution copolymerization using acrylamide (AM), dimethyldiallylammonium chloride (DADMAC) and ionic liquid (1-allyl-3-methylimidazolium chloride; [Amim]Cl) as copolymerization monomers. The structure and morphology of as-prepared copolymer hydrogel PAMDA were confirmed by Fourier transform infrared (FT-IR), field-emission scanning electron microscope (FE-SEM) and thermogravimetric analysis (TG). The copolymer hydrogel was applied as a novel adsorbent for the rapid removal of Cr (VI) from aqueous solution. The effects of several parameters such as the content of ionic liquid [Amim]Cl, solution pH, contact time, adsorbent dosage and initial Cr (VI) concentration on the adsorption were also investigated. The modification of [Amim]Cl significantly enhanced Cr (VI) adsorption. The adsorption equilibrium data fitted with Langmuir isotherm model better than Freundlich isotherm model. The maximum adsorption capacity for Cr (VI) ions was 74.5 mg L(-1) at 323 K based on Langmuir isotherm model. The removal rate could reach 95.9% within 10 min at 323 K and the adsorption process of Cr (VI) on PAMDA was well described by the pseudo-second-order kinetic model. The activation energy of adsorption was further investigated and found to be 1.094 kJ mol(-1), indicating the adsorption of Cr (VI) onto PAMDA was physisorption.

Light-responsive amphiphilic copolymer coated nanoparticles as nanocarriers and real-time monitors for controlled drug release.

Herein, light-responsive nanocarriers based on hollow mesoporous silica (HMS) nanoparticles modified with spiropyran-containing light-responsive copolymer (PRMS-FA) were fabricated via a simple self-assembly process. HMS modified with long-chain hydrocarbon octadecyltrimethoxysilane was an ideal base material owing to its good biocompatibility and drug capability. The spiropyran-containing amphiphilic copolymer could shift its hydrophilic-hydrophobic balance to become hydrophilic upon UV (λ = 365 nm) irradiation and then break away from the hydrophobic surface of the HMS core, followed by the uncaging and release of the pre-loaded anticancer drug. Simultaneously, the fluorescence resonance energy transfer (FRET) process based on the structural transformation of PRMS-FA was observed, which could act as a real-time monitor for the light-controlled drug release. Our model experiments in vitro tested and verified that this composite nanocarrier has good biocompatibility, active tumour targeting to the folate receptor over-expressed in tumour cells, is non-toxic to normal cells and that light-controlled drug release with real-time monitoring can be achieved.

Amphiphilic oligomer-based micelles as cisplatin nanocarriers for cancer therapy.

Polymeric micelles (∼10 nm) have been prepared from the amphiphilic oligomer comprising oligomeric polystyrene as the hydrophobic inner core and half of EDTA (-N(CH2COOH)2) as the hydrophilic outermost shell. After chelating cisplatin with -N(CH2COOH)2 in water, polymeric micelles containing Pt on the spherical surface have been easily obtained. Since the chelate group is introduced into the amphiphilic oligomer as the terminal group by a RAFT agent, the chelation of cisplatin with PS(COOH)2 is almost stoichiometric. The drug carrier based on PS(COOH)2 showed a high loading efficiency (>70%) towards cisplatin. The release of the therapeutic Pt from the cisplatin-loaded composites (PS(COOH)2-Pt) triggered under weak acidic conditions resulted in good Pt-release and accumulation in tumor cells. Both in vitro and in vivo, the chelated cisplatin inhibited Sk-Br3 cancer more effectively than the intact cisplatin does. Furthermore, neither PS(COOH)2 nor PS(COOH)2-Pt showed obvious systematic toxicity.

Coumarin-containing photo-responsive nanocomposites for NIR light-triggered controlled drug release via a two-photon process.

A new multifunctional nanovehicle for tumor therapy and cell imaging was fabricated by coating NIR light-responsive polymers (HAMAFA-b-DDACMM) onto the surface of octadecyltrimethoxysilane (C18)-modified hollow mesoporous silica nanoparticles (HMS@C18) via self-assembly. First, the targeting NIR light-responsive block copolymer was synthesized by the RAFT living polymerization of [7-(didodecylamino) coumarin-4-yl] methyl methacrylate with hydroxyethylacrylate and N-(3-aminopropyl) methacrylamide hydrochloride and then grafted with folic acid (FA). The copolymers could be disrupted by excitation by a femtosecond NIR light laser (800 nm) via a two-photon absorption process due to the high two-photon absorption cross-section of the coumarin moiety. In order to enhance the drug loading capacity and biological stability of the nanovehicle, HMS nanoparticles modified by hydrophobic octadecyl chains were selected as the "core", which had a considerable drug loading efficiency of more than 70%. Then the core-shell nanocomposites (HMS@C18@HAMAFA-b-DDACMM) were obtained by coating the amphiphilic copolymers onto the core via self-assembly. Under excitation by NIR light at 800 nm, the pre-loaded drugs could be released from the nanocomposites due to the degradation of the light-responsive copolymers and the release efficiency was correlated with the irradiation time and light power. The in vitro experiments indicated that the nanocomposites were easily targeted into the tumor cells that over-expressed folic acid receptor (FR(+)) such as KB cells by endocytosis. Furthermore, the copolymer itself had strong fluorescence, which could be used to track the process of drug delivery.

Visible-light degradable polymer coated hollow mesoporous silica nanoparticles for controlled drug release and cell imaging.

A core-shell nanocomposite based on photo-degradable polymer coated hollow mesoporous silica nanoparticles (HMS) was successfully prepared for targeted drug delivery and visible-light triggered release, as well as fluorescence cell imaging. The HMS nanoparticles were first modified by the long-chain hydrocarbon octadecyltrimethoxysilane (C18) and fluorescent agent Rhodamine B isothiocyanate (RITC), and then encapsulated by a photodegradable amphiphilic copolymer via a self-assembly process. The obtained nanocarrier showed a high drug loading content due to the hollow core and mesopores of the HMS and could target folic acid receptor over-expressed tumor cells efficiently for conjugating folic acid (FA) in the amphiphilic polymer. The drug release could be triggered by the irradiation of green light (500-540 nm) due to the photodegradation of amphiphilic copolymer coated on the HMS. Furthermore, the targeted drug delivery and controlled release processes could be tracked by fluorescence imaging for the doping of RITC on the HMS. The In vitro results suggested that a smart visible light responsive drug delivery system was successfully prepared for the potential applications of cancer diagnosis and therapy.

Facile synthesis of polymer/Au heteronanoparticles.

Oligomeric particles with thiol groups perpendicular to their surface were successfully fabricated in toluene. Uniform oligomer-gold nanocomposites were formed via coupling with gold nanoparticles through anisotropic Au-S interactions. Monodispersed nanoparticles consisting of one Au nanoparticle and one oligomer particle were created after dissociation in THF. Because of the simplicity of the synthetic process, our method should allow for the production of large quantities of these asymmetric nanocolloids.

[Theoretical studies on fluorescence spectra of polyamic acid and it's grafted derivatives].

A theoretical study on the polyamic acid (PAA) and its derivatives with different side chain (GPAA1-4) by semi-empirical PM3 is presented in this paper. After optimization, the authors get their balanceable geometric configurations. For all optimal geometric configurations, there is no imaginary frequency in vibrational analysis, which proves that the geometric configurations are stable. On this basis, the electronic spectra have been calculated by a single-excitation configuration interaction (CIS) method. Tie calculated results are consistent with experimental values on the whole. The authors found that the fluorescence intensity of polyamic acid (PAA) with p-pi conjugation side chain is enhanced obviously, and the longer the alkyl side chain the more intense the fluorescence will be. This will help us to design and synthesize the polymer fluorescence material.