Integration of Myrica rubra-based N-doped carbon dots with Fe3S4 as excellent peroxidase mimics for colorimetric assay and smartphone-based intelligent sensing of p-aminophenol in waters.

To realize the reutilization of waste Myrica rubra in the analytical field, we synthesized Myrica rubra-based N-doped carbon dots (MN-CDs) and further anchored them onto the surface of Fe3S4 to fabricate Fe3S4@MN-CD nanocomposites. The as-fabricated nanocomposites possessed higher peroxidase-mimetic activity than its two precursors, resulting from the synergistic effect between them, and could catalyze colorless 3,3',5,5'-tetramethylbenzidine (TMB) into deep blue oxTMB with a strong 652-nm absorption. Under optimized conditions (initial solution pH, 3.5; incubation temperature, 35 ℃; Fe3S4@MN-CD concentration, 50 µg mL-1, and 652-nm absorption), Fe3S4@MN-CDs were employed for colorimetric assay of p-aminophenol (p-AP) with wide linear range (LR, 2.9-100 µM), low detection limit (LOD, 0.87 µM), and satisfactory recoveries (86.3-105%) in environmental waters. Encouragingly, this colorimetric assay provided the relative accuracy of 97.0-99.4% as compared with  conventional HPLC-UV detection. A portable smartphone-based colorimetric application was developed by combining the Fe3S4@MN-CD-based visually chromogenic reaction with a "Thing Identify" APP software. Besides, we engineered an image-capturing device feasible for field use, in which the internal-compact sealing prevented external light source from entering photography chamber, thereby reducing light interference, and also the bottom light source enhanced the intensity of blue imaging. This colorimetric platform exhibited satisfactory LR (1-500 µM), low LOD (0.3 µM), and fortification recoveries (86.6-99.6%). In the chromogenic reaction catalyzed by Fe3S4@MN-CDs, ·O2- played a key role in concomitant with the participation of •OH and h+. Both the colorimetric assay and smartphone-based intelligent sensing show great promising in on-site monitoring of p-AP under field conditions.

Highly efficient nanocomposites based on molecularly imprinted magnetic covalent organic frameworks for selective extraction of bisphenol A from liquid matrices.

Highly efficient nanocomposites, hydrophobic molecularly imprinted magnetic covalent organic frameworks (MI-MCOF), have been farbricated by a facile Schiff-base reaction. The MI-MCOF was based on terephthalaldehyde (TPA) and 1,3,5-tris(4-aminophenyl) benzene (TAPB) as functional monomer and crosslinker, anhydrous acetic acid as catalyst, bisphenol AF as dummy template, and NiFe2O4 as magnetic core. This organic framework significantly reduced the time consumption of conventional imprinted polymerization and avoided the use of traditional initiator and cross-linking agents. The synthesized MI-MCOF exhibited superior magnetic responsivity and affinity, as well as high selectivity and kinetics for bisphenol A (BPA) in water and urine samples. The equilibrium adsorption capacity (Qe) of BPA on the MI-MCOF was 50.65 mg g-1, which was 3-7-fold higher than of its three structural analogues. The imprinting factor of BPA reached up to 3.17, and the selective coefficients of three analogues were all > 2.0, evidencing the excellent selectivity of fabricated nanocomposites to BPA. Based on the MI-MCOF nanocomposites, the magnetic solid-phase extraction (MSPE), combined with HPLC and fluorescence detection (HPLC-FLD), offered superior analytical performance: wide linear range of 0.1-100 µg L-1, high correlation coefficient of 0.9996, low limit of detection of 0.020 µg L-1, good recoveries of 83.5-110%, and relative standard deviations (RSDs) of 0.5-5.7% in environmental water, beverage, and human urine samples. Consequently, the MI-MCOF-MSPE/HPLC-FLD method provides a good prospect in selective extraction of BPA from complex matrices while replacing traditional magnetic separation and adsorption materials.

Reuse of waste Myrica rubra for green synthesis of nitrogen-doped carbon dots as an "on-off-on" fluorescent probe for Fe3+ and ascorbic acid detection.

As one kind of high nutrition fruits, abandoned Myrica rubra causes great waste due to short storage period. For resource utilization, we herein fabricated the Myrica rubra-based N-doped carbon dots (MN-CDs) by a facile/green hydrothermal method. MN-CDs, fabricated from four regions of China, displayed significant differences in their corresponding fluorescence intensities (FIs). Interestingly, different batches of waxberry samples from the same region (Wenzhou, China) exhibited slight differences in their FIs, and also an excellent anti-photobleaching and anti-salt capacity. Based on Fe3+-triggered quenching effect and fluorescent recovery by redox reaction of AA and Fe3+, MN-CDs were employed to construct an "on-off-on" switch probe for sequential detection of Fe3+ and ascorbic acid (AA). Through Zeta potential, UV spectrum, Stern-Volmer equation, and valence-conduction band theory, the Fe3+-triggered quenching belonged to a static quenching process, which resulted from the synergistic contribution of inner filtering effect and photo-induced electron transfer mechanisms. The linear ranges for Fe3+ and AA detections were 1-1000 and 0.1-1000 mM. The limits of detection were 0.3 µM for Fe3+ in environmental waters, and 0.03 µM for AA in pharmaceutical tablets and fruit juice samples. Under 365-nm UV lamp, the color changes of test papers were easily observed from dark blue and bright blue in the presence of Fe3+ and AA, and thus the MN-CDs-based switch probe could be satisfactorily used for visually qualitative detection of Fe3+ and AA outdoor with our naked eyes. To sum up, MN-CDs not only realize resource reutilization of abandoned Myrica rubra, but also offer an convenient outdoor approach for qualitative detection of Fe3+ and AA in complex matrices.

Ce3+ and Fe2+ co-enhanced ratiometric fluorescence probe utilizing copper nanoclusters and coumarin for sensitive assay of hydrogen peroxide and glucose.

A novel ratiometric fluorescent probe was constructed for sensitive assay of hydrogen peroxide (H2O2) and glucose, which utilized the synergistically enhanced effects of Ce3+ and Fe2+ on copper nanoclusters (CuNCs) and coumarin. In the CuNCs-Ce3+/Fe2+-coumarin system, Ce3+ triggered the aggregation-induced emission phenomenon of CuNCs, and Fe2+ catalyzed the Fenton reaction to efficiently yield hydroxyl radical (•OH). In the presence of H2O2, the 625-nm red fluorescence of CuNCs was sharply quenched owing to the oxidation of CuNCs to Cu(II) by •OH, but the 460-nm blue fluorescence of 7-hydroxycoumarin from the oxidation of coumarin by •OH dramatically increased. Based on the reversible changes in two fluorescence signals, a satisfactorily ratiometric probe was constructed for H2O2 assay with a detection limit (LOD) of 0.6 µM accompanied by a visual color variation from red to blue. For glucose assay, this ratiometric probe gave a linear range of 3.2-160 µM and LOD of 0.96 µM owing to the oxidization of glucose to yield H2O2 in the presence of glucose oxidase and O2. Overall, the newly developed ratiometric probe shows a great prospect in real applications for visual assay of H2O2 and glucose by our naked eyes.

Factors associated with 14-day hospital readmission in frail older patients: A case-control study.

Frailty is a key predictor of readmission among older patients. However, studies on the factors associated with readmission of frail older patients are lacking. This study aims to examine factors associated with 14-day hospital readmission in frail older patients. A retrospective case-control study was conducted. Patients were eligible for inclusion if they were age 65 and over and if their Clinical Frailty Scale (CFS) score was above 4. A total of 210 frail older patients were included. Patients who had partners, experienced a fall within 6 months before hospitalization, had pressure injuries, received surgery or chemotherapy, and received rehabilitation therapy from a physical therapist during hospitalization had increased odds of being readmitted to the hospital within 14 days. Moreover, patients receiving comprehensive geriatric assessment (CGA) services during hospitalization showed a significantly reduced risk of readmission. Adapting CGA and developing continuity care plans from hospitals to the community are crucial.

Fluorescent and visual assay of H2O2 and glucose based on a highly sensitive copper nanoclusters-Ce(III) fluoroprobe.

Herein, we synthesized and characterized glutathione-capped copper nanoclusters (CuNCs) using a convenient one-pot chemical reduction approach based on glutathione as capping and reducing agents. The Ce(III) induced aggregation-induced emission of CuNCs to form a CuNCs-Ce3+ fluoroprobe due to electrostatic and coordination interactions between Ce3+ and CuNCs. In contrast to CuNCs, the fluorescent intensities (FLs) of CuNCs-Ce3+ were enhanced by ~ 40-fold concomitant with 20-nm blue-shift of the maximum emission, and a 3.45-fold lengthening of the average fluorescent lifetime. The FLs of CuNCs-Ce3+ were selectively quenched at 650 nm by hydrogen peroxide (H2O2) via the redox reaction. Based on this phenomenon, the sensitive assay of H2O2 was realized, and the linear range spanned over the range of 14-140 µM. Notably, the visualization of the fluorescence quenched effect of H2O2 could be easily attained. Additionally, glucose could be specifically oxidized by glucose oxidase to produce H2O2, and thus the detection of glucose was achieved according to changes in the concentrations of H2O2. Under optimized conditions, the fluorescent assay of glucose based on the CuNCs-Ce3+ system offered the linear range of 8-48 µM with detection limit of 2.4 µM. Meanwhile, high selectivity of the as-constructed fluorescent assay allows the sensitive detection of H2O2 and glucose in real-world care products and human serum samples, showing a great application potential in their conventional monitoring.

Magnetic amino-functionalized metal-organic frameworks as a novel solid support in ionic liquids-based effervescent tablets for efficient extraction of polycyclic aromatic hydrocarbons in milks.

Herein, a kind of novel multi-layer core-shell nanocomposites (NSPN) was prepared by employing SiO2 and polyvinylpyrrolidone (PVP) polymers as modifiers and amino-functionalized metal-organic frameworks (NH2-MIL101(Fe)) as coating. It was referred to as the NSPN and ILs-based effervescence-assisted dispersive solid-phase microextraction, hereafter abbreviated as NIE-DSM. In terms of extraction efficiency, SiO2 and PVP as modifiers and NH2-MIL(Fe) as coating onto the surface of NiFe2O4 cores played a synergistically enhancing effect on adsorption/extraction. Effervescent tablets were prepared by integrating the NSPN magnetic nanoparticles as adsorbents with imidazolium-based ionic liquids (ILs) as extractants as well as acidic and alkaline sources. Under vigorous dispersion of CO2 bubbles, the NIE-DSM method realized the goal of rapidly diffusing and separating the adsorbent/extractant (~3 min) without needing conventional vortexing or centrifugation step. Consequently, the NIE-DSM approach combined dispersion and adsorption/extractant in a synchronous way. Under optimized conditions, the NIE-DSM/HPLC-FLD method gave low limits of detection (0.008-0.034 µg kg-1) and satisfactory extraction recoveries (74.1-101.6%) for five polycyclic aromatic hydrocarbons (PAHs; fluorene, anthracene, pyrene, chrysene and benzo(a)pyrene) in milk samples. The intra-day and inter-day precision, expressed as relative standard deviations, was < 5.9% and 6.5%, respectively, demonstrating a high precision. Owing to no requirement for electrical power, this method shows great potential for outdoor monitoring of trace-level PAHs in food matrices.

Enhanced the photoelectrochemical performance of Bi2XO6 (X = W, Mo) for detecting hexavalent chromium by modification of CuS.

In this work, Bi2XO6 (X = W, Mo) are synthesized at different temperatures. The results of tests find the optimal temperatures of Bi2WO6 and Bi2MoO6 are 180 and 160°C (BW-180, BM-160). Then, BW-180 and BM-160 are further compounded with different contents of CuS. The results of photoelectrochemical (PEC) tests show that CuS can improve the PEC performance of semiconductor materials, and it has better performance when CuS mass fraction is 5%. These maybe the photoelectron potentials generated by CuS/Bi2XO6 (X = Mo, W) heterojunction reduce the combination of photogenerated electrons and holes. When the PEC sensor based on 5%-CuS/BW-180 detects Cr(VI), it has a linear range of 1-80 µmol/L with detection limit of 0.95 µmol/L, while the PEC sensor based on 5%-CuS/BM-160 detects Cr(VI) has a linear range of 0.5-230 µmol/L and a detection limit of 0.12 µmol/L. Thus, 5%-CuS/Bi2XO6 has potential application in hexavalent chromium detection.

A novel electrochemical sensing platform for detection of dopamine based on gold nanobipyramid/multi-walled carbon nanotube hybrids.

Dopamine homeostasis is an important clinical diagnostic index, because an abnormal level in the human body is closely related to certain serious diseases. Herein, a novel electrochemical sensing platform based on gold nanobipyramid/multi-walled carbon nanotube hybrids (AuNBP/MWCNTs) is developed to detect dopamine in human fluids. Using field emission scanning electron microscopy, it is observed that AuNBPs of about 60 nm with two pyramids are well dispersed on the surface of MWCNTs. Energy-dispersive X-ray spectrometry, X-ray diffraction and X-ray photoelectron spectroscopy confirm that AuNBPs are self-assembled onto the surface of MWCNTs to form the hybrids. Cyclic voltammetry reveals that the AuNBP/MWCNTs exhibit good electrocatalytic activity toward dopamine oxidation owing to the synergistic effects of AuNBPs and MWCNTs. In addition, both cyclic voltammetry and differential pulse voltammetry display three well-resolved and distinct oxidation peaks on the AuNBP/MWCNT-modified glassy carbon electrode. Based on AuNBP/MWCNTs, the newly developed electrochemical sensor is used to detect dopamine in the presence of ascorbic acid and uric acid over a wide linear range from 50 nM to 2.7 mM and a low detection limit of 15 nM (at S/N = 3). The electrochemical sensor can also be applied for the quantitative analysis of dopamine in real samples. Graphical abstract A novel electrochemical sensing platform based on gold nanobipyramid/multi-walled carbon nanotube hybrids (AuNBP/MWCNTs) was proposed to detect dopamine in the presence of ascorbic acid and uric acid.

Fluorescent assay based on phenyl-modified g-C3N4 nanosheets for determination of thiram.

Phenyl-modified graphitic carbon nitride nanosheets (Ph-g-C3N4 NSs) were synthesized by a thermal copolymerization and ultrasonic exfoliation method. The Ph-g-C3N4 NSs are used as a fluorescent assay for determination of thiram. The results of X-ray photoelectron spectroscopy, 13C solid-state nuclear magnetic resonance and Fourier transform infrared spectra confirm that phenyl group is integrated into the heptazine network of g-C3N4. Compared to the g-C3N4 NSs, the Ph-g-C3N4 NSs show bigger stokes shift about 185 nm and higher fluorescence intensity. The fluorescence of Ph-g-C3N4 NSs is quenched by Cu2+ via the photo-induced electron transfer mechanism, which then recovers in the presence of thiram. The fluorescence restoring of Ph-g-C3N4 NSs is correlated with the concentration of thiram. Under the optimized conditions, the fluorescent intensity of g-C3N4 NSs at excitation/emission wavelengths of 310/455 nm give a linear range of 33.0-670 nM with detection limit of 9.90 nM. While fluorescent assay based on the Ph-g-C3N4 NSs show the linear range of 6.70-1300 nM at excitation/emission wavelengths of 310/495 nm with detection limit of 2.01 nM. Graphical abstract Schematic representation of fluorescent "on-off-on" assay based on phenyl-modified graphitic carbon nitride nanosheets (Ph-g-C3N4 NSs) for determination of thiram.

Visible light driven photoelectrochemical sensor for chromium(VI) by using BiOI microspheres decorated with metallic bismuth.

Composites were prepared from BiOI and Bi/BiOI-X (where x can be 1, 2, 3, or 4) by a one-step solvothermal method and used to design a photoelectrochemical (PEC) assay for chromium(VI). The chemical composition and morphology of the materials were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The results of UV-vis DRS (Diffuse reflection spectra) and photoluminescence show the composites to have higher visible light absorption and a lower electron recombination rate compared to BiOI alone. Photogenerated electrons reduce hexavalent chromium to trivalent chromium, and the consumption of electrons cause noticeable enhances of the photocurrent density after the addition of Cr(VI). Thus, the Cr(VI) concentration can be measured by monitoring the increase of photocurrent density. The Bi/BiOI-3 material displays the best performance for detecting Cr(VI). The method has a wide linear range (1 to 230 µM) and a low detection limit of 0.3 µM (at S/N = 3). It is stable, selective, reproducible and was applied to the determination of nitrite in spiked tap water and lake water samples. Graphical abstract Schematic presentation of a electrochemical sensor based on Bi/BiOI for the determination of Cr(VI).

A nanocomposite consisting of gold nanobipyramids and multiwalled carbon nanotubes for amperometric nonenzymatic sensing of glucose and hydrogen peroxide.

Gold nanobipyramids were synthesized by a seed-mediated growth method and then supported by multi-walled carbon nanotubes (denoted as AuNBP/MWCNTs). The electrocatalytic activity of the AuNBP/MWCNTs on a glassy carbon electrode (GCE) towards direct glucose oxidation and hydrogen peroxide reduction was superior to that of AuNBPs and MWCNTs. The modified GCE, operated at a typical working voltage of +0.15 V (vs. SCE) and in 0.1 M NaOH solution, exhibits a linear response in the 10 µM to 36.7 mM glucose concentration range with a 3.0 µM detection limit (at S/N = 3) and a sensitivity of 101.2 µA mM-1 cm-2. It also demonstrates good sensitivity towards hydrogen peroxide in at pH 7 solution at a working potential of -0.50 V (vs. SCE), with a linear response range from 5.0 µM to 47.3 mM, a sensitivity of 170.6 µA mM-1 cm-2 and a detection limit of 1.5 µM. Graphical abstract A electrochemical sensing platform based on the use of gold nanobipyramids and multi-walled carbon nanotubes nanocomposites (AuNBP/MWCNTs) is described for the determination of glucose and hydrogen peroxide.

Coping experience of health concerns and physical disability for older Chinese people: A qualitative, descriptive study.

In this qualitative, descriptive study, we explored the perspectives of older, community-dwelling Chinese people regarding their experiences of coping with a physical disability and their health concerns. Twenty participants were interviewed in-depth, and data were analyzed using content analysis. Five themes with 13 subthemes emerged that described older people's experiences of coping with health concerns and disability: (i) ignoring health concerns; (ii) managing self; (iii) seeking medical help; (iv) living with physical disability; and (v) relying on limited resources. Most participants did not have sufficient access to health services due to physical disability and financial deficits, so they tended to ignore their health conditions or tackle them independently before seeking medical help. At the same time, they were impacted on by social and cultural factors. Policies are required that offer more resources to community-dwelling people with disabilities in China.

Development of an "on-off-on" fluoroprobe utilizing an anthrylimidazole-based fluorescent ionic liquid for sensitive Cr(VI) and ascorbic acid detection.

Developing a rapid detection method of Cr(VI) and ascorbic acid (AA) is vital in the food and environmental fields. Herein, an anthrylimidazole-based fluorescent ionic liquid (AI-FIL) with the advantageous fluorescent properties was successfully prepared and used to construct a promising "on-off-on" fluoroprobe for rapid/sensitive Cr(VI) and AA detection. Cr(VI) could effectively quench the fluorescence of AI-FIL owing to the inner-filter effect and photoinduced electron-transfer process. However, the decreased fluorescence could be rapidly recovered by AA owing to the redox reaction between AA and Cr(VI). For Cr(VI) detection, a satisfactorily linear response (0.03-300 µM) was achieved with the corresponding detection limit of 9 nM. For AA detection, a good linearity from 1 to 1000 µM was obtained with the resultant detection limit of 0.3 µM. Moreover, the AI-FIL based fluoroprobe was successfully utilized for Cr(VI) and AA detection in food and water samples with satisfactory accuracy and precision.

Polystyrene nanoplastics induced size-dependent developmental and neurobehavioral toxicities in embryonic and juvenile zebrafish.

Because of widespread environmental contamination, there is growing concern that nanoplastics may pose a risk to humans and the environment. Due to their small particle size, nanoplastics may cross the blood-nerve barrier and distribute within the nervous system. The present study systematically investigated the uptake/distribution and developmental/neurobehavioral toxicities of different sizes (80, 200, and 500 nm) of polystyrene nanoplastics (PS) in embryonic and juvenile zebrafish. The results indicate that all three sizes of PS could cross the chorion, adsorb by the yolk, and distribute into the intestinal tract, eye, brain, and dorsal trunk of zebrafish, but with different patterns. The organ distribution and observed developmental and neurobehavioral effects varied as a function of PS size. Although all PS exposures induced cell death and inflammation at the cellular level, only exposures to the larger PS resulted in oxidative stress. Meanwhile, exposure to the 80 nm PS increased the expression of neural and optical-specific mRNAs. Collectively, these studies indicate that early life-stage exposures to PS adversely affect zebrafish neurodevelopment and that the observed toxicities are influenced by particle size.

A novel ratiometric nanoprobe based on copper nanoclusters and graphitic carbon nitride nanosheets using Ce(III) as crosslinking agent and aggregation-induced effect initiator for sensitive detection of hydrogen peroxide and glucose.

Herein, glutathione-capped copper nanoclusters (CuNCs) and graphitic carbon nitride nanosheets (g-C3N4 NSs) were synthesized by a facile one-pot chemical reduction and directly thermal pyrolysis following ultrasonic exfoliation approaches, respectively. The introduction of Ce(III) (Ce3+) played dual functions in constructing a fluorescence-enhanced ratiometric nanoprobe (g-C3N4 NSs-Ce3+-CuNCs), i.e., triggering aggregation-induced emission of CuNCs and conjugating g-C3N4 NSs with CuNCs by virtue of electrostatic and coordination interactions. The as-fabricated nanohybrid displayed 460 and 625 nm dual-emitting peaks, attributing to the emission of g-C3N4 NSs and CuNCs, respectively. Upon addition of H2O2, the 625 nm emission was dramatically quenched, whereas the 460 nm emission remained nearly unchanged, thereby causing obvious color changes from purple to blue under a 365-nm UV lamp. A ratiometric fluorescent assay, based on g-C3N4 NSs-Ce3+-CuNCs, was devised for sensitive and visual detection of H2O2, which spanned the linear range of 2-100 µM with a detection limit of 0.6 µM. In the presence of glucose oxidase, the ratiometric nanoprobe could be simultaneously employed to detect glucose across the linear range of 1.6-320 µM with a detection limit of 0.48 µM. In milk and human serum samples, the fortified recoveries for H2O2 and glucose by the nanoprobe were in the range of 95.5-103.6% with RSDs <3.8%. The real detection levels for glucose are consistent with those by a standard glucometer. As such, the ratiometric nanoprobe offers a promising methodology for several practical applications, such as point-of-care diagnosis and workplace health evaluations.

A novel raiometric fluorescence probe based on silicon quantum dots and copper nanoclusters for visual assay of l-cysteine in milks.

l-cysteine (l-Cys) plays an important role in many physiological processes. The previously reported methodologies for l-Cys detection have many drawbacks, and thus the development of specific/sensitive approaches is crucial for its direct/quick assay in food matrices. Herein, silicon quantum dots (SiQDs) and glutathione-stabilized copper nanoclusters (CuNCs) were successfully synthesized and integrated as a ratiometric fluorescent probe for assay l-Cys assay in milks. The fluorescence of SiQDs was quenched by CuNCs through fluorescence resonance energy-transfer process. Upon addition of l-Cys, the 440-nm fluorescence of SiQDs changed insignificantly, while the 650-nm fluorescence of CuNCs decreased significantly. Ratiometric fluorescence signal was linear in the l-Cys concentration range of 0.25 µM to 2.5 mM with a detection limit of 75 nM and visual color changes from red to blue. The probe can realize rapid and portable detection without the participation of intermediate ions, and has good selectivity and accuracy for l-cysteine in milk samples.

Sulfur quantum dot-based "ON-OFF-ON" fluorescence platform for detection and bioimaging of Cr(vi) and ascorbic acid in complex environmental matrices and biological tissues.

Based on an "assembling-fission" principle, stable sulfur quantum dots (SQDs) were synthesized using sublimed sulfur as a precursor and PEG-400 as a passivator. The fluorescence intensities (FIs) of SQDs were efficiently quenched by Cr(vi) due to formation of SQD/Cr(vi) complexes through the inner-filter effect. When ascorbic acid (AA) was introduced into the SQD/Cr(vi) system, SQD fluorescence was restored due to AA-induced reduction of Cr(vi) to Cr(iii). Consequently, a SQD-based "ON-OFF-ON" platform was constructed for sequential detection of Cr(vi) and AA. Under optimized conditions, the FIs of SQDs were linearly dependent on the concentrations of Cr(vi) and AA, yielding linear ranges of 0.005-1.5 and 0.01-5.5 mM with detection limits of 1.5 and 3 µM, respectively, in waters, serum and tablet samples. After a 24 h incubation, the SQDs displayed strong, quenched and recovered blue fluorescence, respectively, in the SQD, SQD/AAO/Cr(vi) and SQD/Cr(vi) systems in live HeLa cells and zebrafish embryos/larvae. A blue fluorescence was displayed in the yolk of zebrafish embryos, and yolk and head of larvae. This study demonstrates the efficacy of SQD systems for environmental and biological applications in complex matrices, and for direct observation of Cr bioaccumulation in organisms by bioimaging.

Knowledge of medical professionals, their practices, and their attitudes toward traditional Chinese medicine for the prevention and treatment of coronavirus disease 2019: A survey in Sichuan, China.

This study aimed to investigate the knowledge, practices, and attitudes of medical professionals toward Traditional Chinese Medicine (TCM) for the prevention and treatment of coronavirus disease 2019 (COVID-19). All 401 medical professionals were surveyed using an anonymous with an investigator using the Questionnaire star APP. The participants answered 14 questions; of the 401 participants, 55.2% agreed with the statement "TCM can be used for the prevention and treatment of COVID-19," 40.4% remained neutral, and 4.4% disagreed. Moreover, 75.3% agreed with the statement "There is no specific drug for COVID-19," 67% agreed with the statement "TCM can develop immunity to COVID-19" and 62.1% agreed with "TCM can alleviate the symptoms of patients with COVID-19." Meanwhile, 69.1% were aware that TCM has been recommended for COVID-19 by the National Health Commission of the People's Republic of China. Regarding the selection of sources of knowledge on whether "TCM can be used for the prevention and treatment of COVID-19," There were 277, 123, 82, 369, and 17 participants selected sources from "Hospital training," "Academic journals," "Academic Conferences," "Social media platforms (such as WeChat)" and "Others," respectively. Further, 358 participants will take TCM for the prevention of COVID-19. Multiple logistic regression analysis showed that age, major and received TCM treatment within the last five years were independent factors affecting the participants' attitudes. In the absence of specific drugs for COVID-19, more than half of the participants agreed that TCM could be used for the prevention and treatment of COVID-19 and most participants are willing to take TCM to prevent COVID-19, although unsure about its effectiveness. The main information sources on TCM for the treatment and prevention of COVID-19 were social platforms and hospital training.

Effects of strophanthidin on intracellular calcium concentration in ventricular myocytes of guinea pig.

Effect of strophanthidin (Str) on intracellular calcium concentration ([Ca2+]i) was investigated on isolated ventricular myocytes of guinea pig. Single ventricular myocytes were obtained by enzymatic dissociation technique. Fluorescent signal of [Ca2+]i was detected with confocal microscopy after incubation of cardiomycytes in Tyrode' s solution with Fluo3-AM. The result showed that Str increased [Ca2+]i in a concentration-dependent manner. The ventricular myocytes began to round-up into a contracture state once the peak level of [Ca2+]i was achieved in the presence of Str (10 micromol L(- 1)), but remained no change in the presence of Str (1 and 100 nmol L(-1)). Tetrodotoxin (TTX), nisodipine, and high concentration of extracellular Ca2+ changed the response of cardiomycytes to Str (1 and 100 nmol L(-1)) , but had no obvious effects on the action of Str (10 micromol L(-1)). The elevation of [Ca2+]i caused by Str at all of the detected concentrations was partially antagonized by rynodine (10 micromol L(-1)) or the removal of Ca2+ from Tyrode's solution. In Na+, K+ -free Tyrode' s solution, the response of cardiomycytes in [Ca2+]i elevation to Str (10 micromol L(-1)) was attenuated, while remained no change to Str (1 and 100 nmol L(-1)). TTX, nisodipine, and high concentration of extracellular Ca2+ changed the response of cardiomycytes to Str at all of the detected concentrations in Na+, K+ -free Tyrode's solution. The study suggests that the elevation of [Ca2+]i by Str at the low (nomomolar) concentrations is partially mediated by the extracellular calcium influx through Ca2+ channel or a "slip mode conductance" of TTX sensitive Na+ channel. While the effect of Str at high (micromolar) concentrations was mainly due to the inhibition of Na+, K+ -ATPase. Directly triggering the release of intracellular Ca2+ from sarcoplasmic reticulum (SR) by Str may be also involved in the mechanism of [Ca2+]i elevation.