A magnetic protein biocompass.

The notion that animals can detect the Earth's magnetic field was once ridiculed, but is now well established. Yet the biological nature of such magnetosensing phenomenon remains unknown. Here, we report a putative magnetic receptor (Drosophila CG8198, here named MagR) and a multimeric magnetosensing rod-like protein complex, identified by theoretical postulation and genome-wide screening, and validated with cellular, biochemical, structural and biophysical methods. The magnetosensing complex consists of the identified putative magnetoreceptor and known magnetoreception-related photoreceptor cryptochromes (Cry), has the attributes of both Cry- and iron-based systems, and exhibits spontaneous alignment in magnetic fields, including that of the Earth. Such a protein complex may form the basis of magnetoreception in animals, and may lead to applications across multiple fields.

N-Doping of Graphene Aerogel as a Multifunctional Air Cathode for Microbial Fuel Cells.

One of the main challenges faced by microbial fuel cells (MFCs) generating voltage is how to facilitate the oxygen reduction reaction (ORR) process using a specifically designed air cathode, especially by optimizing a three-phase catalytic interface and enhanced O2 diffusion on it. Herein, a three-dimensional porous N-doped graphene aerogel (NGA) is polymerized onto a steel mesh (SM) to construct a simple structure of an air cathode (NGA-x/SM) via hydrothermal synthesis and subsequent freeze-drying treatment; more specifically, NGA was simultaneously used as an efficient ORR catalyst layer and breathable gas diffusion layer to improve the performance of MFCs. In this system, the NGA-5/SM (with a precursor concentration of x = 5.0 mg mL-1) makes itself a perfect candidate to be used as an air cathode. Characterization parameters reveal that sub-micrometer micropores, defective multilayer structures, and the highest proportion of pyridinic-N (48.1%) exist in NGA-5/SM. Furthermore, electrochemical measurements demonstrate that it has an oxygen reduction peak potential of 0.63 V, a Tafel slope of 187 mV dec-1, and closest 4e- transfer pathway (n = 3.2-3.5). These data prove that a three-phase boundary can naturally form in NGA-5/SM, where the ORR occurs. More importantly, this work provides a proof of concept that a Pt-free air cathode could be prepared with high-efficiency NGA by a two-step preparation method to achieve a MFC maximum power density of 1593 mW m-2.

Recent progress of polar stationary phases in CEC and capillary liquid chromatography.

The stationary phases including the nonpolar and polar stationary phases in microscale separations have been greatly developed. This review describes the recent progress of the polar stationary phases (PSPs) with the focus on their preparation and the interesting applications in the field of CEC and capillary liquid chromatography (CLC) covering the literatures from the middle of 2006 to the middle of 2008. The PSPs described herein were summarized into three types as open-tubular, particle-packed and monolithic stationary phases for either CEC or CLC, and the separation mechanisms are of hydrophilic interaction, chiral selection, ion-exchange and/or electrostatic interaction, etc. After overviewing the literatures published in the last 2 years, the research efforts on PSPs for CEC and CLC have been remaining in the fabrication of open-tubular and monolithic capillary columns; whereas, the research endeavor of PSPs on particulate-packed format seemed to decline most likely due to the commercial availability of various packing particles for CEC and CLC.

[Thrombolysis of rabbit's pulmonary embolism with thrombus-targeted urokinase immune liposome].

OBJECTIVE: To develop thrombus-targeted urokinase immune liposome through incorporating D-dimer monoclonal antibody (DDmAb) to liposome and observe the thrombolytic efficiency in a rabbit pulmonary thromboembolism (PE) model. METHODS: Reverse-phase evaporation method was used to develop targeted urokinase immune liposome by coupling DDmAb to urokinase liposome (liposomal-encapsulated urokinase) with glutaraldehyde. The PE models were induced by injecting 4 autologous emboli (2 mm x 5 mm) through jugular vein catheter into pulmonary arteries. New Zealand white rabbits (n = 32) were randomized into four groups: A group (TBS), B group (150 000 IU/kg UK), C group (30 000 IU/kg urokinase liposome) and D group (30 000 IU/kg urokinase immune liposome). The right ventricular pressure and the emboli size in pulmonary arteries were determined. RESULTS: The right ventricular pressure increased significantly in PE rabbits (P < 0.01), the average value is (6.75 +/- 6.82) mm Hg (1 mm Hg = 0.133 kPa). Eighty minutes post various treatments, right ventricular pressure remained unchanged as post PE in group A [(40.15 +/- 11.22) mm Hg vs. (41.67 +/- 14.23) mm Hg], decreased to baseline level in group B and D [(34.71 +/- 8.67) mm Hg vs. (33.98 +/- 9.32) mm Hg, (30.65 +/- 6.67) mm Hg vs. (30.77 +/- 6.85) mm Hg, all P > 0.05], decreased but not returned to normal value in group C. Residual emboli size remained unchanged in group A and partly reduced in group C and more significantly reduced in group B and D. Hemorrhage of heart, kidney and liver was evidenced in group A but not in other groups. CONCLUSION: Acute PE could be successfully treated by the thrombus-targeted urokinase immune liposome with D-dimer monoclonal antibody.

The covalently bonded cellulose tris(3,5-dimethylphenylcarbamate) on a silica monolithic capillary column for enantioseparation in capillary electrochromatography.

A chiral capillary monolithic column for capillary electrochromatography (CEC) was prepared by covalent bonding of cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) on the silica monolithic matrix within the confine of a 50-microm i.d. bare fused silica capillary. Several pairs of enantiomers including neutral and basic analytes were baseline resolved on the newly prepared chiral capillary monolithic column in CEC with aqueous mobile phases. Fast enantioseparation was achieved due to the favorable dynamic properties of silica monolith. The covalent bonding of CDMPC as the chiral stationary phase for CEC also enabled the use of THF in mobile phase for enantioseparation of prazquantel by overcoming the incompatibility of THF and the physically coated CDMPC on a column.

Polyvinylidene fluoride effects on the electrocatalytic properties of air cathodes in microbial fuel cells.

The use of polyvinylidene fluoride (PVDF) as a binder was investigated in order to prepare the active carbon catalyst and carbon black diffusion layers of a microbial fuel cell cathode. Compared with other binders, PVDF performed competitively as it did not require a lengthy curing time and high curing temperature. Results of XRD characterization showed that the typical ß-PVDF was enhanced as PVDF content ratio increased. SEM results indicated that the catalyst layer easily peeled off due to the low binder concentration of binder, but the high binder content was deemed undesirable because the large amount of non-conductive PVDF interrupted the percolation path. The optimum binder concentration was double checked using Tafel and EIS tests. Results indicated that the cathode with 10% PVDF is the optimum operated concentration. The cathode can obtain 180mV of cathode potential and the smallest total impedance of 2500Ω, which are consistent with the SEM analysis. Moreover, the cathode with 10% PVDF concentration produced a maximum power density of 1600mWm-2, suggesting that PVDF can compete with other traditional binders.

Assessing species biomass contributions in microbial communities via metaproteomics.

Microbial community structure can be analyzed by quantifying cell numbers or by quantifying biomass for individual populations. Methods for quantifying cell numbers are already available (e.g., fluorescence in situ hybridization, 16-S rRNA gene amplicon sequencing), yet high-throughput methods for assessing community structure in terms of biomass are lacking. Here we present metaproteomics-based methods for assessing microbial community structure using protein abundance as a measure for biomass contributions of individual populations. We optimize the accuracy and sensitivity of the method using artificially assembled microbial communities and show that it is less prone to some of the biases found in sequencing-based methods. We apply the method to communities from two different environments, microbial mats from two alkaline soda lakes, and saliva from multiple individuals. We show that assessment of species biomass contributions adds an important dimension to the analysis of microbial community structure.

United membrane biological reactor in the treatment of wastewater.

The united membrane biological reactor( UMBR) was studied for the treatment of some simulate and municipal wastewater. The removal efficiency for COD and turbidity are greater than 80% and 99% respectively. Effluent COD is less than 100 mg/L while turbidity less than 5. The removal of LAS in bath wastewater is greater than 70%. In treatment of dinning-hall wastewater, removal of fatty oil is greater than 90%, and its concentration in effluent is less than 5 mg/L. The match of biological reactor and the membrane separation component were calculated. The stable performance of wastewater treatment can be maintained by the optimization of operation conditions and the cleanout of membranes.

[Effect of Galla chinensis on the surface strengthening of bovine dentine in vitro].

PURPOSE: To evaluate the effect of Galla chinensis extract (GCE) on strengthening the surface properties of bovine dentine in vitro. METHODS: Forty-five bovine dentine blocks were prepared and randomly divided into three groups to undergo a modified anti-acid pH-cycling regimen. Treatments were 4 g/L aqueous solution of Galla chinensis, 1 g/L NaF(positive control) and distilled deionized water (DDW, negative control). Surface dentine microhardness was assessed before and after the pH-cycling regimen and the percentage of microhardness loss (PML) was calculated. Then specimens were analyzed with scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDXS). Statistical analysis was performed by SPSS17.0 software package. RESULTS: Compared with DDW, GCE significantly reduced dentinal microhardness loss (P<0.05). No significant difference of the PML was found between GCE and NaF groups (P>0.05). Both SEM images and elemental contents were similar between the GCE and NaF group. CONCLUSIONS: Galla chinensis can enhance the surface properties of bovine dentine and may inhibit dentine caries progression and protect tooth dentine from erosion in this laboratory study.

Characterization of dentin matrix biomodified by Galla chinensis extract.

INTRODUCTION: The aim of this study was to systemically investigate the potential of Galla chinensis extract (GCE) to interact with the dentin matrix to improve its biochemical and biomechanical properties and structural stability. METHODS: The fully demineralized dentin matrices were prepared and biomodified by 0.4% and 4% GCE solutions, with 5% glutaraldehyde and distilled deionized water as positive and negative controls, respectively. The GCE-dentin matrix interaction was assessed by Fourier transform infrared spectroscopy. The biomodification effects of GCE on the biochemical, biomechanical, and structural properties were assessed by a series of assays including denaturation temperature, swelling ratio and enzymatic biodegradation rate, elastic modulus, ultimate tensile strength, and transmission electron microscopy. RESULTS: GCE could interact with dentin matrix through formation of hydrogen bonds. Compared with negative control, the GCE and glutaraldehyde-treated dentin matrix showed significantly higher denaturation temperature, lowered swelling ratio, and reduced biodegradability against enzymatic digestion. GCE treatment significantly increased elastic modulus values of dentin matrix in a concentration- and time-dependent manner. Biomodification by GCE maintained the ultimate tensile strength and structural integrity of dentin matrix after storage in proteolytic conditions. CONCLUSIONS: GCE can stabilize the dentin matrix against thermal and proteolytic challenges, improve its biomechanical properties, and maintain its structural integrity with long duration. The mechanism is probably due to the formation of GCE-dentin matrix complex.

Effects of 45S5 bioglass on surface properties of dental enamel subjected to 35% hydrogen peroxide.

Tooth bleaching agents may weaken the tooth structure. Therefore, it is important to minimize any risks of tooth hard tissue damage caused by bleaching agents. The aim of this study was to evaluate the effects of applying 45S5 bioglass (BG) before, after, and during 35% hydrogen peroxide (HP) bleaching on whitening efficacy, physicochemical properties and microstructures of bovine enamel. Seventy-two bovine enamel blocks were prepared and randomly divided into six groups: distilled deionized water (DDW), BG, HP, BG before HP, BG after HP and BG during HP. Colorimetric and microhardness tests were performed before and after the treatment procedure. Representative specimens from each group were selected for morphology investigation after the final tests. A significant color change was observed in group HP, BG before HP, BG after HP and BG during HP. The microhardness loss was in the following order: group HP>BG before HP, BG after HP>BG during HP>DDW, BG. The most obvious morphological alteration of was observed on enamel surfaces in group HP, and a slight morphological alteration was also detected in group BG before HP and BG after HP. Our findings suggest that the combination use of BG and HP could not impede the tooth whitening efficacy. Using BG during HP brought better protective effect than pre/post-bleaching use of BG, as it could more effectively reduce the mineral loss as well as retain the surface integrity of enamel. BG may serve as a promising biomimetic adjunct for bleaching therapy to prevent/restore the enamel damage induced by bleaching agents.

Polyacrylamide-based monolithic capillary column with coating of cellulose tris(3,5-dimethylphenyl-carbamate) for enantiomer separation in capillary electrochromatography.

A hydrophilic chiral capillary monolithic column for enantiomer separation in CEC was prepared by coating cellulose tris(3,5-dimethylphenyl-carbamate) (CDMPC) on porous hydrophilic poly(acrylamide-co-N,N'-methylene-bisacrylamide) (poly(AA-co-MBA)) monolithic matrix with confine of a fused-silica capillary. The coating conditions were optimized to obtain a stable and reproducible chiral stationary phase for CEC. The effect of organic modifier of ACN in aqueous mobile phase for the enantiomer separation by CEC was investigated, and the significant influence of ACN on the enantioresolution and electrochromatographic retention was observed. Twelve pairs of enantiomers including acidic, neutral, and basic analytes were tested and nine pairs of them were baseline-enantioresolved with acidic and basic aqueous mobile phases. A good within-column repeatability in retention time (RSD = 2.4%) and resolution (RSD = 3.2%) was obtained by consecutive injections of a neutral compound, benzoin, on a prepared chiral monolithic column, while the between-column repeatability in retention time (RSD = 6.4%) and resolution (RSD = 9.6%) was observed by column-to-column examination. The prepared monolithic stationary phase showed good stability in either acidic or basic mobile phase.

A mesoporous silica nanoparticles immobilized open-tubular capillary column with a coating of cellulose tris(3,5-dimethylphenyl-carbamate) for enantioseparation in CEC.

An approach of immobilizing mobile crystalline material (MCM)-41 mesoporous silica nanoparticles on the inner wall of an open-tubular (OT) capillary as the support for coating chiral selector of cellulose tris(3,5-dimethylphenyl-carbamate) (CDMPC) was carried out. By taking advantage of the improved phase ratio of OT capillary with the immobilization of MCM-41 mesoporous material, the cellulose derivative of CDMPC as the chiral selector was simply coated on the MCM-41 nanoparticle layer via the hydrogen-bonding interaction, and the enantioseparation was successively carried out. Eight pairs of acidic, neutral and basic enantiomers were resolved in capillary electrochromatography or capillary liquid chromatography mode. The concentration of CDMPC for coating was systematically investigated to obtain the optimized chromatographic properties on enantioseparation by controlling the supposed film thickness of CDMPC on MCM-41 nanoparticle layer. Comparing with a bare fused silica capillary column coated with CDMPC under the same coating procedure as MCM-41-modified capillary did, the MCM-41-modified capillary column offered much higher enantioselectivity. This result indicated the significance of using the mesoporous nanoparticles as the electrochromatographic support to enhance the phase ratio of OT capillary column in capillary electrochromatography and capillary liquid chromatography. For investigating the effect of experimental conditions on the enantioseparation with this prepared OT capillary column, the content of organic modifier acetonitrile in the mobile phase was thus extensively evaluated to achieve a better chiral separation.

Recent progress in polar stationary phases for CEC.

This review summarizes most of the recent developments in the preparation and application of polar stationary phases for CEC covering the literature published since the year 2004. These polar stationary phases have been adopted for separation of analytes by the modes of packing column CEC, open-tubular CEC (o-CEC) and monolithic column CEC. Currently, development of o-CEC using biomolecules, such as protein and DNA, as the immobilized ligands is highlighted partly due to the simplicity of preparation. Furthermore, monolithic columns have been extended quickly, particularly inorganic materials-based monoliths, such as silica, zirconia, hafnium, etc., as an alternative to packed columns have been developed quickly.

Preparation and evaluation of rigid porous polyacrylamide-based strong cation-exchange monolithic columns for capillary electrochromatography.

A CEC monolithic column with strong cation-exchange (SCX) stationary phase based on hydrophilic monomers was prepared by in situ polymerization of acrylamide, methylenebisacrylamide, and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) in a complete organic binary porogenic solvent consisting of DMSO and dodecanol. The sulfonic groups provided by the monomer AMPS on the surface of the stationary phase generate an EOF from anode to cathode, and serve as an SCX stationary phase at the same time. The monolithic stationary phase exhibited normal-phase chromatographic behavior for neutral analytes. For charged analytes, electrostatic interaction/repulsion with the monolith was observed. The strong SCX monolithic column has been successfully employed in the electrochromatographic separation of basic drugs, peptides, and alkaloids extracted from natural products.

Capillary electrochromatography with zwitterionic stationary phase on the lysine-bonded poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolithic capillary column.

A polymer-based neutral monolithic capillary column was prepared by radical polymerization of glycidyl methacrylate and ethylene dimethacrylate in a 100 mum id fused-silica capillary, and the prepared monolithic column was subsequently modified based on a ring opening reaction of epoxide groups with 1 M lysine in solution (pH 8.0) at 75 degrees C for 10 h to produce a lysine chemically bonded stationary phases in capillary column. The ring opening reaction conditions were optimized so that the column could generate substantial EOF. Due to the zwitterionic functional groups of the lysine covalently bonded on the polymer monolithic rod, the prepared column can generate cathodic and anodic EOF by varying the pH values of running buffer during CEC separation. EOF reached the maximum of -2.0 x 10(-8) m2v(-1)s(-1) and 2.6 x 10(-8) m2v(-1)s(-1) with pH of the running buffer of 2.25 and 10, respectively. As a consequence, neutral compounds, ionic solutes such as phenols, aromatic acids, anilines, and basic pharmaceuticals were all successfully separated on the column by CEC. Hydrophobic interaction is responsible for separation of neutral analytes. In addition, the electrostatic and hydrophobic interaction and the electrophoretic migration play a significant role in separation of the ionic or ionizable analytes.