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The Fe3O4@MIL-100(Fe) hybrid composites are successfully synthesized via an in-situ growth method and characterized using various techniques. The ability of the magnetic metal–organic framework to promote photo-Fenton like processes is investigated using levofloxacin as a representative substrate. The results show that the composite with a Fe3O4:MIL-100(Fe) mass ratio of 1:4 has a higher degradation efficiency (up to 93.4%) than Fe3O4, MIL-100(Fe), and the other fabricated composites. This higher catalytic activity is ascribed to the synergistic effect between Fe3O4 and MIL-100(Fe), by which the quick separation of hole-electron pair from MIL-100(Fe) and the efficient reduction of Fe3+ to Fe2+ in the photo-Fenton reaction are mutually promoted. Moreover, the composite shows favorable recyclability without apparent loss of apparent photo-Fenton activity even after five cycles, and more importantly, can be recovered magnetically. The possible degradation mechanism and intermediates of levofloxacin in the photo-Fenton reaction have been tentatively proposed based on free radical quenching, electron paramagnetic resonance and mass spectrometry analysis. Finally, the developed Fe3O4@MIL-100(Fe) is successfully applied for the removal of levofloxacin from spiked wastewater with removal efficiencies ranging from 77.9 to 85.5%, which indicates that the proposed system has significant potential for wastewater treatment applications.

Fe 3 O 4 @nSiO 2 @mSiO 2 was prepared successfully and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), infrared spectrometer (FT-IR), BET surface area measurements and Zeta potential analysis techniques. The contact time, initial concentration of congo red, temperature and pH on adsorption capacity were studied. The adsorbent shows highly efficient adsorption properties, with maximum adsorption capacity of 1428 mg g − 1 for congo red, which is much higher than the other adsorbents (normally below 300 mg g − 1 ). The adsorption kinetics and isotherm of congo red on Fe 3 O 4 @nSiO 2 @mSiO 2 were systematically investigated and found that the adsorption kinetics and isotherm were well fitted by pseudo-second-order kinetic and Langmuir isotherm model.

The appropriate projection of axons within the nervous system is a crucial component of the establishment of neural circuitry. Draxin is a repulsive axon guidance protein. Draxin has important functions in the guidance of three commissures in the central nervous system and in the migration of neural crest cells and dI3 interneurons in the chick spinal cord. Here, we report that the distribution of the draxin protein and the location of 23C10-positive areas have a strong temporal and spatial correlation. The overexpression of draxin, especially transmembrane draxin, caused 23C10-positive axon bundles to misproject in the dorsal hindbrain. In addition, the overexpression of transmembrane draxin caused abnormal formation of the ganglion crest of the IX and X cranial nerves, misprojection of some anti-human natural killer-1 (HNK-1)-stained structures in the dorsal roof of the hindbrain, and a simultaneous reduction in the efferent nerves of some motoneuron axons inside the hindbrain. Our data reveal that draxin might be involved in the fascicular projection of cranial nerves in the hindbrain.

A new microextraction technique named in-syringe low-density ionic liquid dispersive liquid–liquid microextraction (LDIL-DLLME) followed by separation using high performance liquid chromatography has been developed to determine the levels of four pyrethroid insecticides (i.e., deltamethrin, fenvalerate, permethrin, and bifenthrin) in environmental water samples. In the developed method, an ionic liquid (IL) was used for the first time instead of an organic solvent, which is most often used in low-density solvent-based microextraction methods. The IL was placed in a long syringe needle using a microsyringe. It was then dispersed by drawing the sample solution into the syringe. The extraction was finished in the syringe, taking full advantage of the low-density property, and making this method easier and quicker. Several parameters affecting the experimental efficiency of LDIL-DLLME, such as the needle's inner diameter, salt addition, the volume of IL and sample, rotation speed and duration of centrifugation and ultrasound were thoroughly studied. Under optimized conditions, in the range of 1 to 500 μg L−1, good linearity was obtained, with coefficients of determination greater than 0.9994. Three spiked water samples were studied, and recovery ranged from 88.0 to 102.8%, with relative standard deviations (RSDs) ranging from 0.3 to 6.7%. The limits of detection (LODs) for the four pyrethroid insecticides were in the range of 0.88–1.71 μg L−1 and enrichment factors (EFs) were in the range of 242 to 257. The proposed method provides an inexpensive, rapid, simple and eco-friendly process for evaluating pyrethroid insecticides in environmental samples, making it a potential method for the pretreatment of experimental samples.

A novel and simple method for effervescence-assisted dispersive liquid–liquid microextraction based on the solidification of a floating ionic liquid using a special collection method combined with high-performance liquid chromatography is developed for the determination of four benzoylureas in water samples. In this method, the ionic liquid (IL), trihexyl(tetradecyl)phosphonium tetrafluoroborate, is used rather than organic drops, which have limitations, as the extraction solvent for the first time in dispersive liquid–liquid microextraction based on the solidification of floating organic drops (DLLME-SFO). Due to the high viscosity of the IL, it can be quickly collected in the lid of the centrifuge tube after solidification, which combines the advantages of both dispersive liquid–liquid microextraction and liquid phase microextraction based on the solidification of a floating IL. Furthermore, effervescence is used to disperse the IL, thereby avoiding the use of an organic dispersant. The influence of various experimental factors, such as the form of the effervescent material, IL quantity, base to acid ratio in the effervescent tablet, weight ratio of IL to effervescent tablet, ultrasonication time, centrifugation time, extraction temperature, sample pH, extraction time and salt addition, are optimized using a central composite design and the one-factor-at-a-time approach. Under the optimal conditions, good linearity was obtained for the four BUs from 2 to 500 μg L−1, with correlation coefficients ranging from 0.9994 to 0.9995. The recoveries were 90.2–100.2% with relative standard deviations ranging from 1.3–4.4%. The limits of detection for the analytes were between 0.77 to 1.58 μg L−1, and the enrichment factors ranged from 206 to 228. Additionally, this method was successfully applied for the determination of four BUs in real water samples.

A novel dispersive liquid–liquid microextraction (DLLME) method is proposed for the detection of five acaricides (clofentezine, fenpyroximate, diafenthiuron, pyridaben and spirodiclofen) in tea infusions prior to analysis by high-performance liquid chromatography (HPLC). For this method, a nanofluid prepared by dispersing magnetic zinc oxide nanoflower (FeO4@ZnO) nanoparticles in 1-octyl-2,3-dimethylimidazolium bis(trifluoromethanesulfonimide) was used as an extractant. After extraction, the nanofluid was magnetically collected by the addition of FeO4@ZnO nanoparticles without centrifugation. In DLLME, the joint use of an ionic liquid (IL)-based nanofluid and magnetic retrieval is unprecedented and makes this microextraction process rapid and effective. The main parameters affecting the extraction efficiency were optimized by an orthogonal experiment and a single-factor experiment using tea infusions. Under the optimal conditions, the recoveries of the analytes were between 83.0 and 104.4%, the limits of detection ranged from 0.44 to 1.0 μg L−1, and the intra-day precision and inter-day precision were both lower than 7.5%. The proposed method was successfully applied to the analysis of acaricides in four tea infusions, and the recoveries were between 79.2 and 93.1%, with RSDs of 0.4 to 5.8%. The developed method is promising as an environmentally friendly, convenient, and efficient sample preparation technique.

A novel liquid phase microextraction method based on the solidification of floated ionic liquids (SFIL-LPME) was developed to determine four phthalate esters (diethyl phthalate, diallyl phthalate, benzyl butyl phthalate, and dicyclohexyl phthalate) in environmental waters and bottle beverages and subsequently separate them using high-performance liquid chromatography. In this work, we customized a tributyldodecylphosphonium tetrafluoroborate ([P4 4 4 12][BF4]) ionic liquid (IL) to obtain a low density such that it can be solidified at a low temperature, and then used as an extraction solvent in liquid-phase microextraction based on the solidification of floated organic drops (SFO-LPME). This means that more potential ILs can be customized to broaden extraction solvents in SFO-LPME. To identify the significant factors that affect extraction efficiency, parameters such as the volume of [P4 4 4 12][BF4], the extraction time, the rotation speed, the extraction temperature and the ionic strength were optimized using a Plackett–Burman design. A central composite design was then used to optimize the identified significant factors to study the effect of interactions on the experiment. Under these optimized conditions, the extraction recoveries of the four phthalate esters in water samples ranged from 73.0 to 94.6% and in bottled beverage were from 70.2 to 101.3%, with relative standard deviations (RSDs) ranging from 0.6 to 8.2% and 0.6 to 7.8%. Good linearity for both water samples and bottled beverages were obtained in the range of 5–500 μg L−1, with correlation coefficients greater than 0.9993. The limits of detection for the four phthalate esters varied from 0.27 to 1.1 μg L−1 for water samples and 1.22 to 2.36 μg L−1 for bottled beverages. The two developed methods were then successfully applied to the determination of phthalate esters in environmental waters and bottled beverages.

A graphene-modified, magnetic polypyrrole nanocomposite (Fe 3 O 4 @PPy/RGO) was fabricated through a facile chemical route and its application as an adsorbent for the removal of a dye was also demonstrated. The as-prepared Fe 3 O 4 @PPy/RGO nanocomposite was characterized by Fourier transform infrared (FT-IR) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), N 2 adsorption–desorption, and zeta potential analysis techniques. The Fe 3 O 4 @PPy/RGO nanocomposite showed excellent water dispersibility because of the hydrophilicity of Fe 3 O 4 and RGO. Adsorption experiments indicated that Fe 3 O 4 @PPy/RGO adsorbs methylene blue fast and efficiently, with an adsorption capacity of up to 270.3 mg g −1 . The kinetic adsorption data fit the pseudo-second-order model and the isotherm data followed the Langmuir model. Additionally, adsorption of MB on Fe 3 O 4 @PPy/RGO also can utilize the electrostatic interaction and π–π interaction between Fe 3 O 4 @PPy/RGO and MB. Moreover, compared to other nanoparticle adsorbents, the as-prepared Fe 3 O 4 @PPy/RGO is highly flexible and easy to operate and retrieve. Most importantly, it is easy to disperse, which enables its potential application in wastewater treatment.

A novel and simple ionic-liquid-mingled air-assisted liquid–liquid microextraction based on solidification of floating organic droplets combined with high performance liquid chromatography was developed for the determination of six benzoylureas (BUs) in water and honey samples. In this method, a mixture of low-density and low melting point extraction solvents and aqueous sample solutions was rapidly sucked up and injected several times using a glass syringe. The influence of the main factors on the efficiency of this procedure is studied. Under the optimal conditions, the enrichment factors (EFs) for BUs were acquired in the range of 144 to 187, limits of detection (LODs) were between 0.01 and 0.1 μg L−1 and limits of quantitation (LOQs) were changed in the range of 0.03 and 0.33 μg L−1. The obtained extraction recoveries ranged from 84.03% to 109.20% with intra-day lower than 4.5%, and inter-day precision lower than 6.5%. The method is successfully applied to determine the BUs in environmental water and honey samples with recoveries in the range of 78.57–109.72%, which proved the potential use of this method in real samples.

A novel water-based slow injection ultrasound-assisted emulsification microextraction (SI-USAEME) method followed by ultra-high performance liquid chromatography-tandem mass spectrometry analysis was developed for the rapid pretreatment and determination of deoxynivalenol (DON) and its metabolite, de-epoxy-deoxynivalenol (DOM-1), in maize and pork samples. After optimization, the method recoveries for DON and DOM-1 ranged from 73 to 85 % with intraday and interday variations less than 9.4 and 9.2 %, respectively. The limits of detection for DON were 4.2 μg kg(-1) in maize and 6.2 and 5.9 μg kg(-1) for DON and DOM-1, respectively, in pork. In addition, an immunoaffinity column (IAC) was prepared. A study comparing the IAC cleanup method, the solid-phase extraction (SPE) cleanup method, and the proposed SI-USAEME method was presented. The water-based SI-USAEME method could become a simple, low-cost alternative to the conventional IAC and SPE method. The method was successfully applied to the analysis of commercial maize and pork products.

The mesencephalic V neurons and tectobulbar axons in chick embryo project over long distances that appear during the early development of the chick optic tectum. The mesencephalic V neuron and tectobulbar axonal growth begin at Hamburger and Hamilton stage 14 and stage 18, respectively. Both fibers proceed downward from the dorsal to the ventral side of the lateral wall of the optic tectum and then turn caudally and join the medial longitudinal fasciculus. Their axons appear in the most superficial layer of the tectum at early stages and do not cross the dorsal midline of the tectum. Here, we report the role of draxin, a recently identified axon guidance protein, in the formation of the ventrally directed tectum axonal tracts in chicken embryo. draxin is expressed in a high dorsal to low ventral gradient in chick optic tectum. In vitro experiments show that draxin repels neurite outgrowth from dorsal tectum explants. In vivo overexpression resulted in inhibition or misrouting of axon growth in the tectum. Therefore, draxin may be an important member of the collection of repulsive guidance molecules that regulate the formation of the ventrally directed tectum axon tracts.

Axon guidance proteins are critical for the correct wiring of the nervous system during development. Several axon guidance cues and their family members have been well characterized. More unidentified axon guidance cues are assumed to participate in the formation of the extremely complex nervous system. We identified a secreted protein, draxin, that shares no homology with known guidance cues. Draxin inhibited or repelled neurite outgrowth from dorsal spinal cord and cortical explants in vitro. Ectopically expressed draxin inhibited growth or caused misrouting of chick spinal cord commissural axons in vivo. draxin knockout mice showed defasciculation of spinal cord commissural axons and absence of all forebrain commissures. Thus, draxin is a previously unknown chemorepulsive axon guidance molecule required for the development of spinal cord and forebrain commissures.

A 5 wt%Na2WO4–2 wt%Mn/SiC monolithic foam catalyst was applied in the oxidative coupling of methane. This catalyst showed the same high activity as the conventional 5 wt%Na2WO4–2 wt%Mn/SiO2 catalyst with no dilution gas and a temperature of 850 °C (>24% methane conversion, 51% C2 (ethylene and ethane) selectivity), but also an excellent heat transfer feature as the significant hot spots did not occur in the catalyst bed. The SiC- and SiO2-supported catalysts were characterized by BET, SEM, XRD and XPS, respectively.

Ni-nanoparticle-embedded mesoporous titania/silica catalyst was successfully synthesized in a one-pot process using homogeneous impregnation in sol–gel-derived titanium-silica gel, without any other organic additives and/or templating agents. The catalyst with NiO loading of 10 wt% and TiO2/SiO2 (wt) of 50:50 is highly catalytic active and stable for CO2 reforming of methane and its physicochemical properties were investigated by means of BET, H2-TPR, XRD, TEM and TG/DTA techniques, respectively. Under the condition of an atmospheric pressure at 850 °C and a gas hour space velocity (GHSV) of 1.8 × 10 4 ml h - 1 g cat - 1 , the conversion of CH4 and CO2 over 10 (wt%) NiO/TiO2–SiO2 (50:50) catalyst remained almost constant, at about 88% and 97%, for 30 h, respectively. The high activity and stability are attributed to the strong metal-support interactions, such as in Ni2.44Ti0.72Si0.07O4.

Carbon dioxide reforming of methane to synthesis gas has been investigated with Ni catalysts supported on SiC monolithic foam. The structure and properties of the catalysts were characterized by BET, SEM and XRD techniques. The novel catalysts exhibited not only the highest activity but also remarkable stability. Of which, 7 wt%Ni/SiC showed the highest activity at 750 °C, During the 100 h performance testing experiment on stream, the conversion of CH4 and CO2 remained almost constant, at about 94.0% and 95.0%, respectively.

An in situ ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) method was developed as a new approach for the detection of four pyrethroid pesticides in environmental water samples. The method is fast, simple, accurate and environmentally friendly. The hydrophobic ionic liquid, [C8MIM]-NTf2, formed by the water-soluble ionic liquid [C8MIM]Cl and the ion exchange reagent LiNTf2 was used as the extraction solvent. The experimental parameters affecting the extraction efficiency, including the amount of the IL, the extraction and the centrifugation times and the salt concentration were investigated and optimized using an orthogonal array design (OAD). A suitable molar ratio of LiNTf2 to [C8MIM]Cl on the recoveries of analytes was determined after OAD optimization. The method showed a good linear response in the range of 0.5 to 500 µg L-1 with correlation coefficients (R2) above 0.9998. The relative standard deviation (RSD) varied from 0.6 to 1.9%. The enrichment factor, the limit of detection and recovery ranged from 134 to 153, 0.02 to 0.18 µg L-1 and 89.7 to 95.6%, respectively. For water samples, the RSD ranged from 0.02 to 2.34% and the recovery ranges from 91.4 to 99.9%.

Generation of the appropriate types, numbers and distribution of neurons during the development of the nervous system requires the careful coordination of proliferation, differentiation, and patterning. In this work, we analyzed the roles of a repulsive axon guidance protein, draxin, on the development of chick spinal cord dI3 interneuron. draxin mRNA and/or protein were detected in the roof plate at first and then the boundary region between the ventricular and the mantle zones in chick spinal cord and dorsal basement membrane of the chick spinal cord. Overexpression of draxin caused the decreased and delayed migration of the dI3 interneuron, the reduction of progenitor cell proliferation, and abnormal localization of some ectopic progenitor-like cells in the mantle zone of the spinal cord. Our data reveal that draxin may be involved in the proper development of the dI3 interneuron in chick spinal cord. Developmental Dynamics 239:1654–1663, 2010. © 2010 Wiley-Liss, Inc.

Draxin, a recently identified axon guidance protein, is essential for the formation of forebrain commissures, and can mediate repulsion of netrin-stimulated spinal commissural axons. Here, we report that draxin binds multiple netrin receptors: DCC (deleted in colorectal cancer), Neogenin, UNC5s (H1, H2, H3), and DSCAM (Down's syndrome cell adhesion molecule). SincedraxinandDccknockouts showed similar phenotype in forebrain commissures formation, we show here the functional importance of draxin/DCC interaction. Draxin interacts with subnanomolar affinity to the netrin receptor DCC, in a region of DCC distinct from its netrin-binding domain.In vitro, neurite outgrowth from cortical and olfactory bulb explants ofDccknock-out mice is significantly less inhibited by draxin, when compared with neurites from explants of wild-type mice. Furthermore, in comparison with wild-type mice, the growth cone collapse in response to draxin is largely abolished inDcc-deficient cortical neurons.In vivo, double heteros ofdraxin/Dccmice show markedly higher frequency of complete agenesis of corpus callosum than either of the single hetero. These results identify DCC as a convergent receptor for netrin and draxin in axon growth and guidance.

Draxin is a repulsive axon guidance protein that plays important roles in the formation of three commissures in the central nervous system and dorsal interneuron 3 (dI3) in the chick spinal cord. In the present study, we report the expression pattern of mouse draxin in the embryonic mouse trunk spinal cord. In the presence of draxin, the longest net migration length of a migrating mouse trunk neural crest cell was significantly reduced. In addition, the relative number of apolar neural crest cells increased as the draxin treatment time increased. Draxin caused actin cytoskeleton rearrangement in the migrating trunk neural crest cells. Our data suggest that draxin may regulate mouse trunk neural crest cell migration by the rearrangement of cell actin cytoskeleton and by reducing the polarization activity of these cells subsequently.