Qualifying P-glycoprotein in drug-resistant ovarian cancer cells: a dual-mode aptamer probe approach.

Drug resistance presents a significant obstacle in treating human ovarian cancer. The development of effective methods for detecting drug-resistant cancer cells is pivotal for tailoring personalized therapies and prognostic assessments. In this investigation, we introduce a dual-mode detection technique employing a fluorogenic aptamer probe for the qualification of P-glycoprotein (P-gp) in drug-resistant ovarian cancer cells. The probe, initially in an "off" state due to the proximity of a quencher to the fluorophore, exhibits increased fluorescence intensity upon binding with the target. The fluorescence enhancement shows a linear correlation with both the concentration of P-gp and the presence of P-gp in drug-resistant ovarian cancer cells. This correlation is quantifiable, with detection limits of 1.56 nM and 110 cells per mL. In an alternate mode, the optimized fluorophores, attached to the aptamer, form larger complexes upon binding to the target protein, which diminishes the rotation speed, thereby augmenting fluorescence polarization. The alteration in fluorescence polarization enables the quantitative analysis of P-gp in the cells, ranging from 100 to 1500 cells per milliliter, with a detection limit of 40 cells per mL. Gene expression analyses, protein expression studies, and immunofluorescence imaging further validated the reliability of our aptamer-based probe for its specificity towards P-gp in drug-resistant cancer cells. Our findings underscore that the dual-mode detection approach promises to enhance the diagnosis and treatment of multidrug-resistant ovarian cancer.

Direct Synthesis of Tertiary Phosphines via Alkoxide-Mediated Deborylative Phosphination of Organoboronates.

The direct transformation of alkylboron has emerged as a versatile and powerful methodology for creating carbon-carbon and carbon-heteroatom bonds. However, its potential application in the formation of carbon and phosphorus remains unexplored. In this study, we present an alkoxide base-promoted reaction system that enables deborylative phosphination of benzylic organoboronates and geminal bis(boronates) via selective C-B bond cleavage. This approach allows for the synthesis of valuable tertiary phosphines in good yields under mild conditions. The practicality and industrial potential of this approach are underscored by the operational simplicity, broad substrate scope, and easy scalability.

Ferrocenylselenoether and its cuprous cluster modified TiO2 as visible-light photocatalyst for the synergistic transformation of N-cyclic organics and Cr(vi).

In this study, fcSe@TiO2 and [Cu2I2(fcSe)2]n@TiO2 nanosystems based on ferrocenylselenoether and its cuprous cluster were developed and characterized by X-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray spectroscopy (EDX), and electron paramagnetic resonance (EPR). Under optimized conditions, 0.2 g L-1 catalyst, 20 mM H2O2, and initial pH 7, good synergistic visible light photocatalytic tetracycline degradation and Cr(vi) reduction were achieved, with 92.1% of tetracycline and 64.5% of Cr(vi) removal efficiency within 30 minutes. Mechanistic studies revealed that the reactive species ˙OH, ˙O2-, and h+ were produced in both systems through the mutual promotion of Fenton reactions and photogenerated charge separation. The [Cu2I2(fcSe)2]n@TiO2 system additionally produced 1O2 from Cu+ and ˙O2-. The advantages of the developed nanosystems include an acidic surface microenvironment provided by Se⋯H+, resourceful product formation, tolerance of complex environments, and excellent adaptability in refractory N-cyclic organics.

Effects of virtual reality-based cognitive interventions on cognitive function and activity of daily living among stroke patients: Systematic review and meta-analysis.

AIMS: To examine the effects of virtual reality-based cognitive interventions on cognitive function and activities of daily living among stroke patients, and to identify the optimal design for such intervention. DESIGN: Systematic review and meta-analysis. DATA SOURCES: Medline, EMBASE, Cochrane, CINANL, JBI-EBP and Web of Science from inception to October 2023. METHODS: Methodological quality was assessed by Risk of Bias Tool. Meta-analyses were assessed by Review Manager 5.4. Subgroup analyses were conducted to explore the influence of study design. Grading of Recommendations Assessment, Development and Evaluation approach was adopted to assess the certainty of evidence. RESULTS: Twenty-five randomized controlled trials (1178 participants) were included. Virtual reality-based cognitive interventions demonstrated moderate-to-large effects in improving global cognitive function (SMD = 0.43; 95% CI [0.01, 0.85]), executive function (SMD = 0.84; 95% CI [0.25, 1.43]) and memory (SMD = 0.65; 95% CI [0.15, 1.16]) compared to control treatments. No significant effects were found on language, visuospatial ability and activities of daily living. Subgroup analyses indicated one-on-one coaching, individualized design and dynamic difficulty adjustment, and interventions lasting ≥ 6 weeks had particularly enhanced effects, especially for executive function. CONCLUSIONS: Virtual reality-based cognitive interventions improve global cognitive function, executive function and memory among stroke patients. IMPLICATIONS FOR THE PATIENT CARE: This review underscores the broad cognitive advantages offered by virtual technology, suggesting its potential integration into standard stroke rehabilitation protocols for enhanced cognitive recovery. IMPACT: The study identifies key factors in virtual technology interventions that effectively improve cognitive function among stroke patients, offering healthcare providers a framework for leveraging such technology to optimize cognitive outcomes in stroke rehabilitation. REPORTING METHOD: PRISMA 2020 statement. PROSPERO REGISTRATION NUMBER: CRD42022342668.

Product-State Distributions of Three-Body Recombination in Zero-Collision-Energy 4He2-Alkaline-Earth-Metal Systems.

The distributions of product states after three-body recombination (TBR) of zero-collision-energy 4He2X systems, with X being 9Be, 24Mg, 40Ca, 88Sr, or 138Ba, are investigated in the hyperspherical representation by quantum mechanically solving the Schrödinger equation. It is found that the weakly bound (dimer) product states are preferentially populated for all of these cases, which could be understood from the joint effects of the lowest incident channel and the relatively long-range behavior of the corresponding nonadiabatic couplings among these lowest incident and shallow recombination channels. For the strongly bound products, since the flow is accessible in the small hyperradial region, their distributions are closely related to the behavior of the nonadiabatic couplings among the corresponding deep recombination channels. Particularly, our results indicate that the products are not always formed exclusively in the most weakly bound state when the scattering lengths among the reactants are relatively large and that there may exist a large fluctuation of the strongly bound products versus their binding energies in the universal region. In addition, the total TBR rates of these nonuniversal systems are also accounted for by the joint effects of the main adiabatic potentials and nonadiabatic couplings.

Effects of mindfulness-based interventions on neuropsychiatric symptoms and psychological well-being on people with subjective cognitive decline and mild cognitive impairment: A meta-analysis.

OBJECTIVES: Neuropsychiatric symptoms (NPS) are highly prevalent in individuals with subjective cognitive decline (SCD) and mild cognitive impairment (MCI), and are strongly linked to accelerated cognitive decline and dementia onset. While mindfulness-based interventions have shown promise in improving psychological well-being in clinical and community settings, their efficacy for individuals in these pre-dementia stages remains unclear. This meta-analysis examined the effects of mindfulness-based interventions on NPS and psychological outcomes in these preclinical cohorts. METHODS: Eligible studies were retrieved from PubMed, EMBASE, JBI EPB, Web of Science, and Cochrane library. Two independent researchers conducted the literature search and data extraction. Cochrane Risk-of-Bias Assessment Tool was used to assess the methodological quality of included studies. Quality of evidence was evaluated using the GRADE approach. Intervention effects were estimated by Hedge's g and 95% confidence interval (CI). RESULTS: A total of 18 randomized controlled trials (including 974 participants from 21 studies) were included in the meta-analysis. The results demonstrated statistically significant immediate post-intervention effects of mindfulness-based interventions on anxiety (g = -0.30, 95% CI -0.49 to -0.11), stress (g = -0.58, 95% CI -0.91 to -0.24), and quality of life (g = 0.50, 95% CI 0.12-0.87). However, no significant effects were found for depression, apathy, mindfulness, and stress-related biomarkers. Follow-up data analysis also did not reveal significant effects for depression and anxiety. CONCLUSIONS: The findings of this meta-analysis suggest that mindfulness-based interventions may improve anxiety, stress, and quality of life in individuals with SCD and MCI. However, more rigorous randomized controlled trials with larger sample sizes and evaluation using physiological parameters are needed to establish more definitive conclusions. Future interventions could consider incorporating cognitive training and health education to address the specific needs of the pre-dementia population. REGISTRATION NUMBER: PROSPERO: CRD42022359906.

Dauricine alleviates cognitive impairment in Alzheimer's disease mice induced by D-galactose and AlCl3 via the Ca2+/CaM pathway.

Alzheimer's disease (AD) is a common neurodegenerative disease in the elderly. Dysregulation of intracellular Ca2+ homeostasis plays a critical role in the pathological development of AD. Dauricine (DAU) is a bisbenzylisoquinoline alkaloid isolated from Menispermum dauricum DC., which can prevent the influx of extracellular Ca2+ and inhibit the release of Ca2+ from the endoplasmic reticulum. DAU has a potential for anti-AD. However, it is unclear whether DAU can exert its anti-AD effect in vivo by regulating the Ca2+ related signaling pathways. Here, we investigated the effect and mechanism of DAU on D-galactose and AlCl3 combined-induced AD mice based on the Ca2+/CaM pathway. The results showed that DAU (1 mg/kg and 10 mg/kg for 30 days) treatment attenuated learning and memory deficits and improved the nesting ability of AD mice. The HE staining assay showed that DAU could inhibit the histopathological alterations and attenuate neuronal damage in the hippocampus and cortex of AD mice. Studies on the mechanism indicated that DAU decreased the phosphorylation of CaMKII and Tau and reduced the formation of NFTs in the hippocampus and cortex. DAU treatment also reduced the abnormally high expression of APP, BACE1, and Aß1-42, which inhibited the deposition of Aß plaques. Moreover, DAU could decrease Ca2+ levels and inhibit elevated CaM protein expression in the hippocampus and cortex of AD mice. The molecular docking results showed that DAU may have a high affinity with CaM or BACE1. DAU has a beneficial impact on pathological changes in AD mice induced by D-galactose and AlCl3 and may act by negative regulation of the Ca2+/CaM pathway and its downstream molecules such as CaMKII and BACE1.

Facile preparation of organosilanes from benzylboronates and gem-diborylalkanes mediated by KOtBu.

Methods to efficiently synthesize organosilanes are valuable in the fields of synthetic chemistry and materials science. During the past decades, boron conversion has become a generic and powerful approach for constructing carbon-carbon and other carbon-heteroatom bonds, but its potential application in forming carbon-silicon remains unexplored. Herein, we describe an alkoxide base-promoted deborylative silylation of benzylic organoboronates, geminal bis(boronates) or alkyltriboronates, allowing for straightforward access to synthetically valuable organosilanes. This selective deborylative methodology exhibits operational simplicity, broad substrate scope, excellent functional group compatibility and convenient scalability, providing an effective and complementary platform for the generation of diversified benzyl silanes and silylboronates. Detailed experimental results and calculated studies revealed an unusual mechanistic feature of this C-Si bond formation.

Redox ferrocenylseleno compounds modulate longitudinal and transverse relaxation times of FNPs-Gd MRI contrast agents for multimodal imaging and photo-Fenton therapy.

Developing a feasible way to feature longitudinal (T1) and transverse (T2) relaxation performance of contrast agents for magnetic resonance imaging (MRI) is important in cancer diagnosis and therapy. Improved accessibility to water molecule is essential for accelerating the relaxation rate of water protons around the contrast agents. Ferrocenyl compounds have reversible redox property for modulating the hydrophobicity/hydrophilicity of assemblies. Thus, they could be the candidates that can change water accessibility to the contrast agent surface. Herein, we incorporated ferrocenylseleno compound (FcSe) with Gd3+-based paramagnetic UCNPs, to obtain FNPs-Gd nanocomposites using T1-T2 MR/UCL trimodal imaging and simultaneous photo-Fenton therapy. When the surface of NaGdF4:Yb,Tm UNCPs was ligated by FcSe, the hydrogen bonding between hydrophilic selenium and surrounding water molecules accelerated their proton exchange to initially endow FNPs-Gd with high r1 relaxivity. Then, hydrogen nuclei from FcSe disrupted the homogeneity of the magnetic field around the water molecules. This facilitated T2 relaxation and resulted in enhanced r2 relaxivity. Notably, upon the near-infrared light-promoted Fenton-like reaction in the tumor microenvironment, hydrophobic ferrocene(II) of FcSe was oxidized into hydrophilic ferrocenium(III), which further increased the relaxation rate of water protons to obtain r1 = 1.90±0.12 mM-1 s-1 and r2 = 12.80±0.60 mM-1 s-1. With an ideal relaxivity ratio (r2/r1) of 6.74, FNPs-Gd exhibited high contrast potential of T1-T2 dual-mode MRI in vitro and in vivo. This work confirms that ferrocene and selenium are effective boosters that enhance the T1-T2 relaxivities of MRI contrast agents, which could provide a new strategy for multimodal imaging-guided photo-Fenton therapy of tumors. STATEMENT OF SIGNIFICANCE: T1-T2 dual-mode MRI nanoplatform with tumor-microenvironment-responsive features has been an attractive prospect. Herein, we designed redox ferrocenylseleno compound (FcSe) modified paramagnetic Gd3+-based UCNPs, to modulate T1-T2 relaxation time for multimodal imaging and H2O2-responsive photo-Fenton therapy. Selenium-hydrogen bond of FcSe with surrounding water molecules facilitated water accessibility for fast T1 relaxation. Hydrogen nucleus in FcSe perturbed the phase coherence of water molecules in an inhomogeneous magnetic field and thus accelerated T2 relaxation. In tumor microenvironment, FcSe was oxidized into hydrophilic ferrocenium via NIR light-promoted Fenton-like reaction which further increased both T1 and T2 relaxation rates; Meanwhile, the released toxic •OH performed on-demand cancer therapy. This work confirms that FcSe is an effective redox mediate for multimodal imaging-guided cancer therapy.

Total alkaloids from the seed embryo of Nelumbo nucifera Gaertn. improve cognitive impairment in APP/PS1 mice and protect Aß-damaged PC12 cells.

The seed embryo of Nelumbo nucifera Gaertn. is a famous traditional Chinese medicine and food which is considered conducive to the prevention of Alzheimer's disease (AD). In this study, the effect and mechanism of TASENN (total alkaloids from the seed embryo of Nelumbo nucifera Gaertn.) on AD mice and amyloid-ß (Aß) injured PC12 cells were evaluated. HPLC-UV analysis showed that the extracted TASENN (purity = 95.6%) mainly contains Liensinine, Isoliensinine, and Neferine (purity was 23.01, 28.02, and 44.57%, respectively). In vivo, oral treatment with TASENN (50 mg/kg/day for 28 days) improved the learning and memory functions of APP/PS1 transgenic mice, ameliorated the histopathological changes of cortical and hippocampal neurons, and inhibited neuronal apoptosis. We found that TASENN reduced the phosphorylation of Tau and the formation of neurofibrillary tangles (NFTs) in APP/PS1 mouse brain. Moreover, TASENN down-regulated the expression of APP and BACE1, ameliorated Aß deposition, and inhibited microglial proliferation and aggregation. The elevated protein expression of CaM and p-CaMKII in APP/PS1 mouse brain was also reduced by TASENN. In vitro, TASENN inhibited the apoptosis of PC12 cells injured by Aß25-35 and increased the cell viability. Aß25-35-induced increase of cytosolic free Ca2+ level and high expression of CaM, p-CaMKII, and p-Tau were decreased by TASENN. Our findings indicate that TASENN has a potential therapeutic effect on AD mice and a protective effect on PC12 cells. The anti-AD activity of TASENN may be closely related to its negative regulation of the CaM pathway.

The design of fluorescein-ferrocene derivatives as HOCl-triggered turn-on fluorescent probes and anticancer prodrugs.

Overexpressed HOCl in tumors can behave as an activator for imaging-guided precision therapy. Herein, a new kind of HOCl-activated molecular platform has been developed aiming at the integration of detection, imaging, and anticancer functions. The design strategy uses a five-membered heterocyclic ring to bridge the fluorescent fluorescein part (FL) and the anticancer ferrocene part (Fc). Three derivatives, namely FL-Fc, FL-NP-Fc and FL-TEG-Fc, were designed with different grafted chains on the fluorescein mother to modulate the hydrophilic and biocompatible capacity. In these molecular platforms, the ferrocene unit serves as the fluorescence emission quencher and masked prodrug. These three could respond to HOCl with good selectivity and sensitivity, showing a turn-on fluorescence signal and anticancer efficacy. FL-TEG-Fc with the highest sensitivity (6.5 × 10-6 M) was successfully used for imaging endogenous HOCl in AGS cells, in which it presented strong toxicity IC50 = 9.5 ± 0.3 µM. The mechanistic study revealed that the five-membered heterocyclic ring of FL-TEG-Fc was broken specifically and effectively by HOCl to release strongly fluorescent fluorescein and a bioactive ferrocene derivative; the obtained ferrocene derivative further generated cytotoxic ˙OH through a Fenton-like reaction. This study provides a potential theranostic strategy against HOCl-overexpressing cancers.

Exogenous spermidine enhances the photosynthetic and antioxidant capacity of citrus seedlings under high temperature.

Studies have not fully explained the underlying mechanism of spermidine-mediated heat tolerance. This study investigated the possible role of spermidine (Spd) in regulating citrus heat tolerance. The results showed that exogenous Spd effectively alleviated the limitation of high temperature (HT) on photosynthesis. Exogenous Spd increased the chlorophyll content, net photosynthetic rate, intercellular carbon dioxide concentration, stomatal conductance, maximum and effective quantum yield of PSII photochemistry, nonphotochemical quenching coefficient, and electron transport rate in citrus seedlings under HT stress, but declined the stomatal limitation value. In addition, Spd treatment promoted the dynamic balance of the citrus enzymatic and non-enzymatic antioxidants system. Spd application significantly increased the activity of superoxide dismutase, peroxidase, catalase, ascorbic acid, and glutathione and the expression level of corresponding genes at high temperature, while reducing the content of H2O2 and malondialdehyde. Therefore, our findings suggested exogenous Spd significantly ameliorated citrus physiological and photosynthetic adaptation under HT stress, thereby providing helpful guidance for citrus cultivation in HT events.

Protective effects of Liensinine, Isoliensinine, and Neferine on PC12 cells injured by amyloid-ß.

Excessive accumulation of amyloid-ß (Aß) is the leading cause of Alzheimer's disease (AD). Liensinine, Isoliensinine, and Neferine are main alkaloids in lotus seed embryos. In this paper, the protective effects of Liensinine, Isoliensinine, and Neferine on Aß25-35 -injured PC12 cells were studied. It was found that Liensinine, Isoliensinine, and Neferine could improve the viability and reduce the apoptosis of PC12 cell induced by Aß25-35 . These three alkaloids could also reduce the level of intracellular free Ca2+ and CaM expression in Aß25-35 -treated cells, thereby inhibiting the phosphorylation of CaMKII and tau. In addition, these three compounds can inhibit the production of ROS in PC12 cells injured by Aß25-35 . Our results suggest for the first time that Liensinine, Isoliensinine, and Neferine can inhibit hyperphosphorylation of tau protein by inhibiting the Ca2+ -CaM/CaMKII pathway, thereby reducing the apoptosis and death of PC12 cells damaged by Aß25-35 . PRACTICAL APPLICATIONS: This study highlighted the protective effects and mechanisms of three main active ingredients (Liensinine, Isoliensinine, and Neferine) in the lotus embryo on a typical cell model of Alzheimer's disease (AD). The results revealed that three alkaloids in this healthy food might exert therapeutic potential for AD.

Changing the shape of wool yarns via laccase-mediated grafting of tyrosine.

The shape of wool yarns was changed by laccase-assisted grafting of tyrosine. Prior to tyrosine grafting a cysteine pre-treatment was optimized aiming to increase the amount of thiol reaction groups available. The best operational conditions for laccase-assisted tyrosine grafting were: i) pre-treatment with cysteine (2.2 mM) in a solution of 20 % ethanol, 15 % propylene glycol and 0.5 % benzyl alcohol, pH = 10, 40 °C; ii) tyrosine grafting with 3.0 mM tyrosine, 18 U/mL laccase, pH = 5, 40 °C. The shape modification was evaluated by number of curly twists determination on the grafted yarn samples. The thermal and mechanical properties of the grafted wool yarns was evaluated by TGA, DSC and breaking strength determination. The amount of free thiols and weight gain were assessed aiming to infer the role of the cysteine pre-treatment on the final tyrosine grafting and shape modification. The laccase-assisted grafting of tyrosine onto wool yarns have influenced the thermal and mechanical properties of the yarns however without compromising their structural integrity for the final application purposes. The developed methodology to impart new shape to wool yarns is presented herein as an environmentally friendly alternative to chemical methods. The new findings revealed great potentialities for application in similar fibers like hair.

Thermal Decomposition Kinetics and Compatibility of 3,5-difluoro-2,4,6-trinitroanisole (DFTNAN).

In this paper, the thermal decomposition behavior of 3,5-difluoro-2,4,6-trinitroanisole (DFTNAN) was studied by differential scanning calorimetry (DSC) and thermogravimetry (TG) by using different heating rates (2, 5, 10, 15 °C·min-1). Subsequently, the kinetic and thermodynamic parameters of non-isothermal thermal decomposition of DFTNAN were calculated. The critical temperature of thermal explosion (Tb) and self-accelerating decomposition temperature (TASDT) were determined to be 249.03 °C and 226.33 °C, respectively. The compatibility of DFTNAN with a number of high explosives (cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX), 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaaza-tetracyclo-[5.5.0.05,9.03,11]-dodecane (CL-20) and dihydroxylammonium 5,5'-bistetrazole-1,1'-diolate (TKX-50)) was studied at different mass ratios using DSC. The criteria to judge the compatibility between the materials were based on a standardization agreement (STANAG 4147). The thermodynamic study results revealed that DFTNAN possessed superior thermal safety and stability. The experimental of compatibility results indicated that the mass ratios of the high explosives in the DFTNAN/RDX, DFTNAN/HMX and DFTNAN/CL-20 compositions more than 40%, 60% and 70% exhibited good compatibility, whereas DFTNAN/TKX-50 demonstrated poor compatibility.

A facile co-crystallization approach to fabricate two-component carbon dot composites showing time-dependent evolutive room temperature phosphorescence colors.

Time-dependent evolutive afterglow materials can increase the security level by providing additional encryption modes in anti-counterfeiting and data encryption. The design of carbon-based materials with dynamic afterglow colors is attractive but formidably challenging. In this study, a facile two-component co-crystallization strategy is designed for the first time to obtain N,S-co-doped carbon dots@isophthalic acid (CDs@IPA) and N,S-co-doped carbon dots@melamine (CDs@MA). CDs@IPA and CDs@MA all exhibiting time-dependent evolutive RTP colors from orange via yellow to green over 1 s, especially that the green afterglow time of CDs@IPA can reach 6 s (τ avg = 582 ms). Studies show that the time-dependent RTP colors originated from two primary emissive centers, low-energy emission of CDs and high-energy emission of host matrix activated by CDs. Due to their distinguishable RTP colors with differentiated lifetimes, the ratios of two RTP emissive bands changed with time during the decay process, resulting in the continuous RTP colors variation in real-time. This two-component carbon dot-based co-crystallization strategy may open a new avenue for the development of time-dependent afterglow color materials.

Design of ferrocenylseleno-dopamine derivatives to optimize the Fenton-like reaction efficiency and antitumor efficacy.

In the current study, six ferrocenylseleno-dopamine derivatives with different structural parameters were designed. Among these derivatives, F4b, containing two ferrocene units and a tertiary amine, showed in vitro anticancer activity with IC50 = 2.4 ± 0.4 µM for MGC-803 cells, and its in vivo studies suggested effective antitumor activity in mice bearing an MGC-803 tumor xenograft. Mechanistic study revealed that the cytotoxicity of these ferrocenylseleno-dopamine derivatives is mainly related to the Fenton-like reaction under physiological conditions, and the tertiary amine in F4b can facilitate the H2O2 decomposition to generate toxic ˙OH which induces apoptosis through CDK-2 inactivation.

N, P-co-doped carbon dots as a dual-mode colorimetric/ratiometric fluorescent sensor for formaldehyde and cell imaging via an aminal reaction-induced aggregation process.

Novel colorimetric and ratiometric fluorometric dual-mode N, P-co-doped carbon nanodots, BPEI-CDs, for highly sensitive and selective detection of formaldehyde (FA) were successfully prepared from N-(phosphonomethyl)iminodiacetic acid (PMIDA) and branched polyethyleneimine (BPEI). The treatment of FA caused a remarkable linear enhancement of ratiometric fluorescence (F501 nm/F408 nm) in a wide range of 0-40 µM with a detection limit (LOD) of 0.47 µM (3σ/k), along with distinct color changes from colorless to light yellow. Mechanistic study shows that this electron-rich system, formed by the cooperative roles of N and P, promoted the FA-induced Schiff bases formation reaction, which contributed to the CD aggregation-induced emission (AIE) "turn-on" response and enhancement of π-conjugation-induced bathochromic behaviors. Furthermore, N, P-co-doped BPEI-CDs were successfully applied to the determination of FA in bean sprout samples. Using the standard addition method, the recoveries ranged from 96.9 to 101.8%, and the relative standard deviation (RSD) was in the range 2.23 to 3.21%. The application for intracellular FA sensing further verified that this novel nanoprobe may offer a new venue for the design of simple, low-cost, and sensitive biosensors. Graphical abstract.

Ferrocene Functionalized Upconversion Nanoparticle Nanosystem with Efficient Near-Infrared-Light-Promoted Fenton-Like Reaction for Tumor Growth Suppression.

By taking advantage of the efficient Förster resonance energy transfer (FRET) between near-infrared (NIR)-responsive lanthanide-doped upconversion nanoparticles (UCNPs) and Fenton reagent ferrocenyl compounds (Fc), a series of Fc-UCNPs was designed by functionalizing NaYF4:Yb,Tm nanoparticles with Fc1-Fc5 via surface-coordination chemistry. Fc-UCNP-Lipo nanosystems were then constructed by encapsulating Fc-UCNP inside liposomes for efficient delivery. Fc-UCNP can effectively release ·OH via a NIR-promoted Fenton-like reaction. In vitro and in vivo studies of Fc1-UCNP-Lipo confirmed the preferential accumulation in a tumor site followed by an enhanced uptake of cancer cells. After cellular internalization, the released Fc1-UCNP can effectively promote ·OH generation for tumor growth suppression. Such a Fc1-UCNP-Lipo nanosystem exhibits advantages such as easy fabrication, low drug dosage, and no ferrous ion release.

Leaf transition from heterotrophy to autotrophy is recorded in the intraleaf C, H and O isotope patterns of leaf organic matter.

RATIONALE: Quantitatively relating 13 C/12 C, 2 H/1 H and 18 O/16 O ratios of plant α-cellulose and 2 H/1 H of n-alkanes to environmental conditions and metabolic status should ideally be based on the leaf, the plant organ most sensitive to environmental change. The fact that leaf organic matter is composed of isotopically different heterotrophic and autotrophic components means that it is imperative that one be able to disentangle the relative heterotrophic and autotrophic contributions to leaf organic matter. METHODS: We tackled this issue by two-dimensional sampling of leaf water and α-cellulose, and specific n-alkanes from greenhouse-grown immature and mature and field-grown mature banana leaves, taking advantage of their large areas and thick waxy layers. Leaf water, α-cellulose and n-alkane isotope ratios were then characterized using elemental analysis isotope ratio mass spectrometry (IRMS) or gas chromatography IRMS. A three-member (heterotrophy, autotrophy and photoheterotrophy) conceptual linear mixing model was then proposed for disentangling the relative contributions of the three trophic modes. RESULTS: We discovered distinct spatial leaf water, α-cellulose and n-alkane isotope ratio patterns that varied with leaf developmental stages. We inferred from the conceptual model that, averaged over the leaf blade, only 20% of α-cellulose in banana leaf is autotrophically laid down in both greenhouse-grown and field-grown banana leaves, while approximately 60% and 100% of n-alkanes are produced autotrophically in greenhouse-grown and field-grown banana leaves, respectively. There exist distinct lateral (edge to midrib) gradients in autotrophic contributions of α-cellulose and n-alkanes. CONCLUSIONS: Efforts to establish quantitative isotope-environment relationships should take into account the fact that the evaporative leaf water 18 O and 2 H enrichment signal recorded in autotrophically laid down α-cellulose is significantly diluted by the heterotrophically formed α-cellulose. The δ2 H value of field-grown mature banana leaf n-alkanes is much more sensitive than α-cellulose as a recorder of the growth environment. Quantitative isotope-environment relationship based on greenhouse-grown n-alkane δ2 H values may not be reliable.