Fully Transient 3D Origami Paper-Based Ammonia Gas Sensor Obtained by Facile MXene Spray Coating.

Developing high-performance chemiresistive gas sensors with mechanical compliance for environmental or health-related biomarker monitoring has recently drawn increasing research attention. Among them, two-dimensional MXene materials hold great potential for room-temperature hazardous gas (e.g., NH3) monitoring regardless of the complicated fabrication process, insufficient 2D/3D flexibilities, and poor environmental sustainability. Herein, a Ti3C2Tx MXene/gelatin ink was developed for patterning electrodes through a facile spray coating. Particularly, the patterned Ti3C2Tx-based coating exhibited good adhesion on the paper substrate against repeated peeling-off and excellent mechanical flexibility against 1000 cyclic stretching. The porous morphology of the coating facilitated the NH3 sensing ability. As a result, the 2D kirigami-shaped NH3 sensor exhibited a good response of 7% to 50 ppm of NH3 with detectable concentrations ranging from 5-500 ppm, decent selectivity over interferences, etc., which could be well-maintained even at 50% stretched state. In addition, with the help of mechanically guided compressive buckling, 3D mesostructured MXene origamis could be obtained, holding promise for detecting the coming direction and height distribution of hazardous gas, e.g., the NH3. More importantly, the as-fabricated MXene/gelatin origami paper could be fully degraded in PBS/H2O2/cellulase solution within 19 days, demonstrating its potential as a high-performance, shape morphable, and environmentally friendly wearable gas sensor.

Construction of 3D sheet-packed hierarchical MoS2/BiOBr heterostructures with remarkably enhanced photocatalytic performance for tetracycline and levofloxacin degradation.

In this paper, MoS2 nanosheets were prepared and deposited on BiOBr microflowers through deposition-hydrothermal strategy. MoS2 exhibited a string of nanosheets with wrinkled layer outlook, and MoS2/BiOBr composites displayed a micro-flower morphology with the diameter of 2-3 µm. Visible-light harvesting performance was significantly improved in the region of 400-600 nm for MoS2/BiOBr. The obtained MoS2/BiOBr samples exhibited tremendous enhanced catalytic activity, which could degrade 92.96% of tetracycline and 90.31% of levofloxacin within 70 min. The photo-generated holes and ⋅OH radicals played the dominant roles in the whole photocatalytic decomposition process. Based on the analysis of DRS, BET, PL, and electrochemical results, the remarkably improved photocatalytic performance may be ascribed to the synergistic effect of strong visible-light harvesting ability, enhanced BET surface area, and faster separation or transfer efficiency of photo-generated charges.

Construction of a new cascade photogenerated charge transfer system for the efficient removal of bio-toxic levofloxacin and rhodamine B from aqueous solution: Mechanism, degradation pathways and intermediates study.

In this work, a novel cascade system (i.e., SnTCPP/g-C3N4/Bi2WO6) is successfully constructed using stannum (II) meso-tetra (4-carboxyphenyl) porphyrin (SnTCPP) as the key photovoltaic agent for the first time. Visible light driven photocatalytic experiments indicated that wt. 12% SnTCPP and 30% Bi2WO6 codecorated g-C3N4 demonstrates the highest photodecomposition capabilities for levofloxacin and rhodamine B, achieving 85.64% and 93.64% degradation rates, respectively. The dramatically enhanced photocatalytic performance mainly raised from the synergetic co-effects among SnTCPP, g-C3N4 and Bi2WO6, including: i) the incorporation of SnTCPP extends the visible light response of the binary Bi2WO6/g-C3N4 heterojunctions, resulting in the highly efficient visible light harvesting; ii) we find that the g-C3N4 not only serves as a promising supporter to trap electrons from Bi2WO6, but also as an interfacial electron-hole pairs transfer moderator, like "volleyball setter" to facilitate the charges transfer between Bi2WO6 and SnTCPP. The presence of the "setter" endows a cascade system for boosting the photodegradation efficiency of levofloxacin and rhodamine B. This study provides a promising design strategy to construct efficient g-C3N4 based heterojunctions suitable for removing pharmaceutical antibiotics and hazardous dyes from various real wastewaters.

Suspension microarray-based comparison of oropharyngeal swab and bronchoalveolar lavage fluid for pathogen identification in young children hospitalized with respiratory tract infection.

BACKGROUND: Respiratory tract infection (RTI) in young children is a leading cause of morbidity and hospitalization worldwide. There are few studies assessing the performance for bronchoalveolar lavage fluid (BALF) versus oropharyngeal swab (OPS) specimens in microbiological findings for children with RTI. The primary purpose of this study was to compare the detection rates of OPS and paired BALF in detecting key respiratory pathogens using suspension microarray. METHODS: We collected paired OPS and BALF specimens from 76 hospitalized children with respiratory illness. The samples were tested simultaneously for 8 respiratory viruses and 5 bacteria by suspension microarray. RESULTS: Of 76 paired specimens, 62 patients (81.6%) had at least one pathogen. BALF and OPS identified respiratory pathogen infections in 57 (75%) and 49 (64.5%) patients, respectively (P > 0.05). The etiology analysis revealed that viruses were responsible for 53.7% of the patients, whereas bacteria accounted for 32.9% and Mycoplasma pneumoniae for 13.4%. The leading 5 pathogens identified were respiratory syncytial virus, Streptococcus pneumoniaee, Haemophilus influenzae, Mycoplasma pneumoniae and adenovirus, and they accounted for 74.2% of etiological fraction. For detection of any pathogen, the overall detection rate of BALF (81%) was marginally higher than that (69%) of OPS (p = 0.046). The differences in the frequency distribution and sensitivity for most pathogens detected by two sampling methods were not statistically significant. CONCLUSIONS: In this study, BALF and OPS had similar microbiological yields. Our results indicated the clinical value of OPS testing in pediatric patients with respiratory illness.

The antioxidant compounds isolated from the fruits of chinese wild raspberry Rubus Chingii Hu.

Raspberry, the fruit of Rubus Chingji Hu, is a widely distributed economic staple food in China. It has long been used as a traditional medicine in mainland China to treat kidney enuresis, nocturnal emission and premature ejaculation in clinic. In this paper, six known compounds (1 - 6) were purified from the fruits of Rubus chingji. Their structures were elucidated as (16α)-16,17-dihydroxy-ent-kauran-2-one17-O-ß-D-glucopyranoside (1), (16R) -16,17-dihydroxy-ent-kaurane-2-one (2), 3,3'-di-O-methylellagic acid 4-(5''-acetyl)-α-L-arabinofuranoside (3), quercilicoside A (4), esculetine (5) and ethyl-ß-D-glucoside (6). All the compounds were isolated from Rubus Chingji Hu for the first time. Compounds 3 and 5 shown distinctive free radical scavenging activities in DPPH and FRAP assays. In addition, no cytotoxicity was observed for compounds 3 and 5 against different cancer cells, suggesting that they might be useful as potential antioxidant agents against various reactive oxygen species.[Formula: see text].

Methylene blue functionalized graphene as binder-free electrode for high-performance solid state supercapacitors.

Electrochemical active small organic molecules are potential electrode materials for supercapacitors due to their sustainable and good redox reversibility. However, the poor electrical conductivity restricts their application in supercapacitors. Herein, a water soluble organic dye of methylene blue (MB) has been supported on graphene (GR) through a facile ultrasonic method to form a methylene blue/graphene (MB/GR) composite. A small amount of MB (13%) in MB/GR composite improves the wettability of GR and supplies pseudocapacitance. The MB/GR composite can be used as a binder-free electrode for supercapacitors, and gives a high specific capacitance of 517 F g-1 at 0.5 A g-1 in 0.5 mol L-1 H2SO4 aqueous electrolyte with a satisfactory capacitive retention of 91% after 2000 consecutive cyclic voltammetry tests at 10 mV s-1. Benefiting from the high specific capacitance of MB/GR composite, the as-assembled symmetrical solid-state supercapacitor (MB/GR//MB/GR) delivers a high energy density of 30.36 Wh kg-1 at 0.7 kW kg-1, and excellent cycle stability (nearly 27% drop after 10,000 consecutive constant current charge-discharge at 5 A g-1). This work offers some enlightenment to design and preparation of high-performance electrode materials for supercapacitors.

An effective strategy for boosting photoinduced charge separation of Ag3PO4 by BiVO4 with enhanced visible light photodegradation efficiency for levofloxacin and methylene blue.

In this paper, a Z-scheme Ag3PO4/BiVO4 photocatalyst was successfully prepared by precipitation-deposition method. The Ag3PO4/BiVO4 composite exhibited enhanced photocatalytic activity and recyclability for levofloxacin and methylene blue degradation under visible light irradiation. In the Ag3PO4/BiVO4-0.4 system, up to 92.44% of the levofloxacin molecules can be decomposed within 180 min and the photocatalytic degradation efficiency can maintain at 92.02% for methylene blue after recycled for 5 times. The enhanced photocatalytic activity of Ag3PO4/BiVO4 heterojunctions could be mainly attributed to the fabrication of hetero-structure between BiVO4 and Ag3PO4. The photogenerated electron-hole pair separation was effectively enhanced based on the photocurrent, electro-chemical impedance spectra and photoluminescence data. Furthermore, the electrons transfer from photoinduced BiVO4 to Ag3PO4 and the visible light harvesting efficiencies were significantly increased due to the BiVO4 hybridization. The ·OH was the main oxidative species in the Ag3PO4/BiVO4 system for the methylene blue decomposition. Finally, a purposed photocatalytic mechanism for methylene blue degradation was discussed in detail on the basis of experimental results.

Hydrothermal synthesis of p-C3N4/f-BiOBr composites with highly efficient degradation of methylene blue and tetracycline.

Construction of heterojunctions with band-suitable different semiconductors has been demonstrated to be an efficient approach to enhance the separation of photoinduced electrons and holes. In this paper, highly efficient heterojuction photocatalysts consisted of porous-C3N4 (p-C3N4) and flowerlike-BiOBr (f-BiOBr) were successfully synthesized via a deposition-hydrothermal method. The SEM and HRTEM images indicated that BiOBr were successfully deposited on the surface of p-C3N4 and the layered p-C3N4/f-BiOBr heterojunctions were formed between p-C3N4 and f-BiOBr. The optimum photocatalytic activity of the p-C3N4/f-BiOBr nanocomposites with weight ratio of 3%p-C3N4 exhibited dramatically improved visible-light photocatalytic activities with 98.42% and 94.25% degradation rates for methylene blue (MB) and tetracycline, respectively. The enhanced activity was mainly attributed to the unique heteojunction architecture, which creates large interfacial surface between the constituent materials for facilitating charge transfer and effectively inhibits the fast recombination of photogenerated electrons and holes. The active species trapping experiment indicated that the O2- was the dominating reactive oxidizing species of p-C3N4/f-BiOBr for MB degradation under visible light irradiation. Moreover, the as-prepared photocatalysts displayed excellent stability in the recycling experiments with no obvious decrease of the degradation efficiencies for MB and tetracycline. Furthermore, the possible photocatalytic degradation mechanism of MB over p-C3N4/f-BiOBr was proposed to better understand the reaction process. The work provides a facile route for rational design of heterojunction photocatalysts with promising prospect for the treatment of antibiotic residues in various wastewaters.

Free-standing graphene/bismuth vanadate monolith composite as a binder-free electrode for symmetrical supercapacitors.

Preparation of new types of electrode material is of great importance to supercapacitors. Herein, a graphene/bismuth vanadate (GR/BiVO4) free-standing monolith composite has been prepared via a hydrothermal process. Flexible GR sheets act as a skeleton in the GR/BiVO4 monolith composites. When used as a binder-free electrode in a three-electrode system, the GR/BiVO4 composite electrode can provide an impressive specific capacitance of 479 F g-1 in a potential window of -1.1 to 0.7 V vs. SCE at a current density of 5 A g-1. A symmetrical supercapacitor cell which can be reversibly charged-discharged at a cell voltage of 1.6 V has been assembled based on this GR/BiVO4 monolith composite. The symmetrical capacitor can deliver an energy density of 45.69 W h kg-1 at a power density of 800 W kg-1. Moreover, it ensures rapid energy delivery of 10.75 W h kg-1 with a power density of 40 kW kg-1.

Free-standing graphene/vanadium oxide composite as binder-free electrode for asymmetrical supercapacitor.

Preparation of free-standing electrode materials with three-dimensional network architecture has emerged as an effective strategy for acquiring advanced portable and wearable power sources. Herein, graphene/vanadium oxide (GR/V2O5) free-standing monolith composite has been prepared via a simple hydrothermal process. Flexible GR sheets acted as binder to connect the belt-like V2O5 for assembling three-dimensional network architecture. The obtained GR/V2O5 composite can be reshaped into GR/V2O5 flexible film which exhibits more compact structure by ultrasonication and vacuum filtration. A high specific capacitance of 358Fg-1 for GR/V2O5 monolith compared with that of GR/V2O5 flexible film (272Fg-1) has been achieved in 0.5molL-1K2SO4 solution when used as binder free electrodes in three-electrode system. An asymmetrical supercapacitor has been assembled using GR/V2O5 monolith as positive electrode and GR monolith as negative electrode, and it can be reversibly charged-discharged at a cell voltage of 1.7V in 0.5molL-1 K2SO4 electrolyte. The asymmetrical capacitor can deliver an energy density of 26.22Whkg-1 at a power density of 425Wkg-1, much higher than that of the symmetrical supercapacitor based on GR/V2O5 monolith electrode. Moreover, the asymmetrical supercapacitor preserves 90% of its initial capacitance over 1000 cycles at a current density of 5Ag-1.

Carbon nanotubes/holey graphene hybrid film as binder-free electrode for flexible supercapacitors.

The practical application of graphene (GR) has still been hindered because of its unsatisfied physical and chemical properties resulting from the irreversible agglomerates. Preparation of GR-based materials with designed porosities is essential for its practical application. In this work, a facile and scalable method is developed to synthesize carbon nanotubes/holey graphene (CNT/HGR) flexible film using functional CNT and HGR as precursors. Owing to the existence of the small amount CNT, the CNT-5/HGR flexible film with a 3D conductive interpenetrated architecture exhibit significantly improved ion diffusion rate compared to that of the HGR. Moreover, CNT-5/HGR flexible film can be used as binder-free supercapacitor electrodes with ultrahigh specific capacitances of 268Fg-1, excellent rate capabilities, and superior cycling stabilities. CNT-5/HGR flexible film could be used to fabricate high-performance flexible supercapacitors electrodes.

Liver X receptor and peroxisome proliferator-activated receptor agonist from Cornus alternifolia.

BACKGROUND: Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear receptors superfamily and are transcription factors activated by specific ligands. Liver X receptors (LXR) belong to the nuclear hormone receptors and have been shown to play an important role in cholesterol homeostasis. From the previous screening of several medicinal plants for potential partial PPARγ agonists, the extracts of Cornus alternifolia were found to exhibit promising bioactivity. In this paper, we report the isolation and structural elucidation of four new compounds and their potential as ligands for PPAR. METHODS: The new compounds were extracted from the leaves of C. alternifolia and fractionated by high-performance liquid chromatography. Their structures were elucidated on the basis of spectroscopic evidence and analysis of their hydrolysis products. RESULTS: Three new iridoid glycosides including an iridolactone, alternosides A-C (1-3), a new megastigmane glycoside, cornalternoside (4) and 10 known compounds, were obtained from the leaves of C. alternifolia. Kaempferol-3-O-ß-glucopyranoside (5) exhibited potent agonistic activities for PPARα, PPARγ and LXR with EC50 values of 0.62, 3.0 and 1.8 µM, respectively. CONCLUSIONS: We isolated four new and ten known compounds from C. alternifolia, and one known compound showed agonistic activities for PPARα, PPARγ and LXR. GENERAL SIGNIFICANCE: Compound 1 is the first example of a naturally occurring iridoid glycoside containing a ß-glucopyranoside moiety at C-6.

Diterpenoid alkaloids from a Tibetan medicinal plant Aconitum richardsonianum var. pseudosessiliflorum and their cytotoxic activity.

The chemical constituents from Aconitum richardsonianum var. pseudosessiliflorum were investigated. The roots of this plant were extracted three times with 90% EtOH at the room temperature. The ethanol extracts were combined and concentrated under reduced pressure to yield residue, which was suspended in water and successively partitioned with chloroform. The chloroform extraction was isolated and purified by silica gel and Sephadex LH-20 column chromatography. Six compounds were isolated and elucidated as delelatine (1), isodelpheline (2), 3-acetylaconitine (3), isoatisine (4), nordhagenine A (5) and yunaconitine (6). Compounds 1-5 were obtained from Aconitum Brunneum for the first time. Compound (1) showed significant cytotoxic activities (IC50= 4.36 µM) against the human tumor cell line P388.

Chemical constituents from Delphinium chrysotrichum and their biological activity.

A new diterpene alkaloid named delphatisine C (1) has been isolated from aerial parts of Delphinium chrysotrichum along with three known norditerpenoid alkaloids delpheline (2), delbrunine (3), and delectinine (4). Their structures were characterized on the basis of their spectral data. All of them were determined by SRB assay for their cytotoxicity, and compound (1) showed significant cytotoxic activities (IC(50)=2.36 µmol/L) against the A549 cell line.

A new norditerpenoid alkaloid from Aconitum taipaicum.

To investigate the chemical constituents of the roots of Aconitum taipaicum, silica gel column chromatography was used for the isolation and purification of compounds. A new norditerpenoid alkaloid, isodelelatine (1), along with five known alkaloids, atisine (2), delfissinol (3), liangshanine (4), hypaconitine (5) and delelatine (6) were isolated and identified. The structure of the new compound was elucidated on the basis of spectral data.

Diaqua-(5-methyl-pyrazine-2-carboxyl-ato-κN,O)iron(II).

In the neutral title complex, [Fe(C(6)H(5)N(2)O(2))(2)(H(2)O)(2)], the coordination geometry aound the Fe(II) atom, which lies on an inversion centre, is distorted octa-hedral comprising two N atoms and two O atoms from two 5-methyl-pyrazine-2-carboxyl-ate ligands, and two water mol-ecules. The crystal structure is stabilized by a network of O-H⋯O hydrogen bonds, resulting in a two-dimensional supra-molecular structure.

[Study on chemical constituents from Delphinium honanense var. piliteram].

OBJECTIVE: To study the chemical constituents from Delphinium honanense var. piliteram. METHOD: The constituents were isolated and purified with chromatographic methods, identified by NMR, MS and IR. RESULT: Six compounds were isolated and elucidated as siwanine E (1), isoatisine (2), 12-epi-napelline (3), acontine (4), ajadelphinine (5) and beta-sitosterol (6). CONCLUSION: Compounds 1-6 are all isolated from the plant for the first time.