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AgsA (aggregation-suppressing protein) is an ATP-independent molecular chaperone machine belonging to the family of small heat shock proteins (sHSP), and it can prevent the aggregation of non-natural proteins. However, the substrate-binding site of AgsA and the functional unit that captures and binds the substrate remain unknown. In this study, different N-terminal and C-terminal deletion mutants of AgsA were constructed and their effects on AgsA oligomer assembly and chaperone activity were investigated. We found that the IXI motif at the C-terminus and the α-helix at the N-terminus affected the oligomerization and molecular chaperone activity of AgsA. In this work, we obtained a 6.8 A resolution structure of AgsA using Electron cryo-microscopy (cryo-EM), and found that the functional form of AgsA was an 18-mer with D3 symmetry. Through amino acid mutations, disulfide bonds were introduced into two oligomeric interfaces, namely dimeric interface and non-partner interface. Under oxidation and reduction conditions, the chaperone activity of the disulfide-bonded AgsA did not change significantly, indicating that AgsA would not dissociate to achieve chaperone activity. Therefore, we concluded that the oligomer, especially 18-mer, was the primary functional unit.

Tb-doped ZrO2 nanotube arrays were first prepared by anodizing the Zr-Tb alloys, and then Ag modified Tb-doped ZrO2 nanotube arrays were obtained by loading Ag onto the Tb-doped ZrO2 nanotube arrays through a thermal decomposition and formaldehyde reduction method. The influences of modification of Ag nanoparticles and AgNO3 concentrations (0.0001, 0.001, 0.01 M) on the light absorption and photoluminescence (PL) properties were determined. Results show that Ag modified samples prepared by the thermal decomposition method exhibited a significant surface plasmon resonance(SPR) effect, and that the absorption and PL emission peaks were markedly enhanced. Compared to the Tb-doped ZrO2 nanotube arrays, the PL intensity of the sample prepared using the thermal decomposition method in 0.001 M AgNO3 solution was enhanced by 45.8%. The samples prepared by the formaldehyde reduction method displayed excessive deposition and oversizing of Ag particles, resulting in worsening of the properties of samples.

Zirconia nanotube-supported H 3 PW 12 O 40 (HPW) catalysts were obtained by loading HPW onto zirconia nanotube arrays which were prepared through anodization of zirconium foil in the mixture of formamide and glycerol (volume ratio = 1:1) containing 1 wt% NH 4 F and 1 wt% H 2 O. The samples were characterized through scanning electron microscope, X-ray diffraction, infrared spectra and thermogravimetric analysis. Various factors affecting the catalytic activities have been investigated. The catalysts, prepared through pretreating the nanotube carrier at 400 °C, followed by loading with 35 wt% HPW and calcining at 200 °C, possess high catalytic activities in the synthesis of fatty acid ethyl ester. Under the optimal reaction conditions, the conversion percentages of lauric acid, oleic acid and stearic acid are all higher than 98.5%.

In this paper, Cu2O films were prepared by an anodisation method in 1.0 wt% NH3·H2O electrolyte. The influence of preparation conditions on photoelectrochemical properties was investigated. Results show that anodisation voltage and reaction time exerted significant influence on semiconductor types and photocurrent values. Only under the conditions of appropriate voltage and time could n-Cu2O films be prepared. When the voltage was 10 V and anodisation time was 30 to 90 min, the films had a larger oxidation photocurrent (n-type semiconductor), with a current density of −101 μA/cm2 to −143 μA/cm2. The reasons for formation of n-Cu2O films have been discussed.

A flexible non-enzymatic glucose sensing material which consists of the CoNi2S4 nanosheets grown on the reticular Nitrogen-doped Carbon Foam substrate (CoNi2S4@NCF) has been successfully fabricated by a simple two-step synthesis process. The micromorphology, composition and valence of the CoNi2S4@NCF are researched by means of FESEM, TEM, XPS and XRD. Subsequently, the glucose sensing characteristics of the CoNi2S4@NCF are studied by Cyclic Voltammetry and Amperometry, and the detection performance of CoNi2S4@NCF synthesized by different processes is compared. Through a series of tests, it is found that when the volume ratio of deionized water to anhydrous ethanol is 30 ml: 30 ml, the prepared CoNi2S4@NCF has excellent glucose sensing properties. The sensitivity is 6.675 μA mM−1 cm−2 and 54.82 μA mM−1 cm−2 over the linear detection range of 0.5–12.5 mM and 12.5–30 mM, respectively. At the same time, the CoNi2S4@NCF has outstanding anti-interference, stability, repeatability and shows good performance in the detection of actual samples. In addition, the synthesized CoNi2S4@NCF has good flexibility and compressibility. Compared with general sensing materials, this flexible material is more conducive to storage and use. It provides a new idea for wearable instruments. All these fully indicate that the fabricated CoNi2S4@NCF have a good prospect in the field of non-enzymatic glucose sensing.

In this paper, Zr foils were first anodised to prepare zirconia nanotube arrays (ZNA), then ZrO 2 nanoparticles were loaded onto the zirconia nanotube arrays by a chemical precipitation method to prepare ZrO 2 -ZrO 2 nanotube array composite films (ZrO 2 -ZNA), finally RhB was supported on the ZNA and ZrO 2 -ZNA to prepare RhB/ZNA and RhB/ZrO 2 -ZNA fluorescent films, respectively. The photoluminescence (PL) properties of RhB/ZNA and RhB/ZrO 2 -ZNA were tested and the effects of annealing temperature and RhB solution concentration on their PL properties were studied. Results show that the PL intensity of RhB/ZrO 2 -ZNA was obviously higher than that of RhB/ZNA, and the emission peaks of RhB/ZrO 2 -ZNA were much stronger when the annealing temperature was 300 °C and the RhB concentrations were between 5 and 40 mg/L. Different from the excitation and emission peaks of RhB/ethanol solutions, those of RhB/ZrO 2 -ZNA composite films were obviously red shifted, and the luminous efficiency of RhB/ZrO 2 -ZNA composite films was much higher.

Zr foils were anodised to prepare zirconia nanotube arrays (ZNA) then Eu 3+ doped ZrO 2 /ZrO 2 nanotube array composite films (Eu ZrO 2 /ZNA) were produced by depositing Eu 3+ doped ZrO 2 components onto the ZNA through a chemical co-precipitation method. The effects of electrolyte and anodisation time on the morphologies, thicknesses, crystal compositions, grain sizes, and photoluminescence (PL) properties of the composite films were investigated. Results show that the preparation conditions, crystal structure, and support material exerted a significant influence on the PL properties of the composite films. When the supports (ZNA) were prepared by anodisation for 20 min, Eu ZrO 2 /ZNA showed an improved PL performance. Under excitation at 232 nm, their emission spectra contained five emission peaks and the intensity of the emission peak at 615 nm was the highest. The relative intensity of the main emission peak was much higher when the ZNA were prepared in an aqueous electrolyte. The PL characteristics of Eu ZrO 2 /ZNA were significantly different from those of the Eu 3+ doped ZrO 2 /TiO 2 nanotube array composite film (Eu ZrO 2 /TNA) and those of Eu 3+ doped ZrO 2 powders (Eu ZrO 2 P).

In this paper, leaflike copper phosphate films were fabricated by anodization of copper foils in mixed phosphate electrolytes. The optimal leaflike morphology was obtained when copper foil was anodized at 10 V for 60 min. Leaflike copper phosphate films had very good catalytic effect on the dyes degradation through Fenton oxidation. The reaction temperature exerted a significant influence on the decolorization ratio. When the temperature was 75 °C, methyl orange, rhodamine B, alizarin red and neutral red solution could be decolorized completely within 5 min (10 g dye solution/4 cm 2 film).

The sectional void fraction measurement for multiphase flow is usually influenced by flow patterns. Inspired by electrical capacitance tomography (ECT) devices applied to flow imaging (whose measured capacitance data contain both the flow pattern and sectional void fraction information), a capacitive array sensor is developed to realize two functions, flow pattern recognition and void fraction measurement, simultaneously; so that the void fraction measurement can be conducted for a certain flow pattern and the measurement accuracy can be expected to be improved. The main idea of the proposed method can be described as: firstly, the proper feature vectors are extracted from the electrical signal to identify the flow pattern (the BPNN model with GDX learning algorithm is used for flow pattern identification); and then the average of electrical signal is applied to estimates the void fraction by the corresponding calibration curve. An experimental platform of air/water two-phase flow is built (on which 3 flow patterns can be generated stably) to test the performance of the proposed method. The results support the correctness and effectiveness of the proposed method.

The image reconstruction of the electrical capacitance tomography (ECT) is an ill-posed and sparse problem. In order to increase the accuracy and speed of the image reconstruction, this paper proposes a new reconstruction algorithm which is based on the extreme learning machine (ELM) with the Landweber iteration method. Firstly, a nonlinear mapping model is established between the pixel gray-scale values and the interelectrode capacitances by using the ELM which has a good learning ability and high speed. Secondly, the Landweber iteration method, which has a good performance in convergence and stability, is applied to calculate the output weight matrix of ELM. Finally, a convergence and stable mapping model of ELM with the Landweber iteration algorithm (L-ELM) for ECT image reconstruction is trained on Matlab platform. Both simulation and measurement tests are carried out to evaluate and analyze the proposed method. Experimental results indicate that the proposed algorithm has good generalization ability and high image reconstruction quality which are better than those of conventional ELM algorithm.

This paper proposes a new method for the volumetric-concentration measurement of coal/biomass/air three-phase flow using multi-sensor data fusion techniques. The method integrates capacitive and electrostatic sensors and incorporates the data fusion model of an adaptive network based fuzzy inference system (ANFIS), which simulates the human׳s understanding of things. The features of the two sensor signals are extracted as the input of the ANFIS under various experimental conditions. The fusion model of the ANFIS establishes the relationship between the volumetric-concentration of the solid phase and the signal features by training with two different learning rules: the gradient descent method only and the hybrid method combining the Kalman filter algorithm with the gradient descent algorithm. Experimental results show that the ANFIS based on the hybrid learning rule outperforms the system based on the gradient descent learning rule and that the fiducial error for biomass and pulverized coal flows are 1.2% and 0.7%, respectively.

Rhodopsin (Rho), a prototypical G protein-coupled receptor (GPCR) in vertebrate vision, activates the G protein transducin (G(T)) by catalyzing GDP-GTP exchange on its α subunit (Gα(T)). To elucidate the determinants of G(T) coupling and activation, we obtained cryo-EM structures of a fully functional, light-activated Rho-G(T) complex in the presence and absence of a G protein-stabilizing nanobody. The structures illustrate how G(T) overcomes its low basal activity by engaging activated Rho in a conformation distinct from other GPCR-G protein complexes. Moreover, the nanobody-free structures reveal native conformations of G protein components and capture three distinct conformers showing the Gα(T) helical domain (⎱HD) contacting the Gβγ subunits. These findings uncover the molecular underpinnings of G protein activation by visual rhodopsin and shed new light on the role played by Gβγ during receptor-catalyzed nucleotide exchange.

Electrical capacitance tomography (ECT) is a computational imaging technology that may be applied to visualize and quantify the cross-sectional permittivity distribution of gas/solid two-phase flow. In consideration of the nonlinearity and ill-posed characteristics of image reconstruction in ECT, this paper presents a new image reconstruction method based on the least squares support vector machine (LSSVM) combined with the bacterial colony chemotaxis (BCC) algorithm to meet the requirements in the observation of transient flow regimes and their evolution from the spout of a dense–dilute burner at the end of a pneumatic conveying pulverized coal system. Firstly, a nonlinear mapping model is established from the measured capacitances to the grayscale values of the image by using the LSSVM, which has good nonlinear learning ability and high convergence rate. Secondly, because it is difficult to select kernel parameters for the LSSVM model, the BCC algorithm, which has global optimization and rapid convergent ability, is applied to construct an objective optimization function for the kernel parameters. Finally, a pneumatic conveying system with a radial biased whirl burner (a typical dense–dilute burner) was built up, and a sequence of images was collected using a 12-electrode ECT system from the spout of the burner to verify the effectiveness of the reconstruction algorithm under several cold conditions. Experimental results indicate that the algorithm can achieve reconstructed images with good quality and identify the subtle change of the transitional flow regimes from the spout of the burner.

Electrical capacitance tomography (ECT) is a non-invasive imaging technique that aims at visualizing the cross-sectional permittivity distribution and phase distribution of solid/gas two-phase flow based on the measured capacitance. To solve the nonlinear and ill-posed inverse problem: image reconstruction of ECT system, this paper proposed a new image reconstruction method based on improved radial basis function (RBF) neural network combined with adaptive wavelet image enhancement. Firstly, an improved RBF network was applied to establish the mapping model between the reconstruction image pixels and the capacitance values measured. Then, for better image quality, adaptive wavelet image enhancement technique was emphatically analyzed and studied, which belongs to a space-frequency analysis method and is suitable for image feature-enhanced. Through multi-level wavelet decomposition, edge points of the image produced from RBF network can be determined based on the neighborhood property of each sub-band; noise distribution in the space-frequency domain can be estimated based on statistical characteristics; after that a self-adaptive edge enhancement gain can be constructed. Finally, the image is reconstructed with adjusting wavelet coefficients. In this paper, a 12-electrode ECT system and a pneumatic conveying platform were built up to verify this image reconstruction algorithm. Experimental results demonstrated that adaptive wavelet image enhancement technique effectively implemented edge detection and image enhancement, and the improved RBF network and adaptive wavelet image enhancement hybrid algorithm greatly improved the quality of reconstructed image of solid/gas two-phase flow [pulverized coal (PC)/air].

This paper describes an integrated instrumentation system for the volumetric-concentration measurement of biomass/coal/air three-phase flow in a pneumatic conveying pipeline. The system combines electrostatic sensors with capacitive sensors and incorporates data fusion techniques. As the electrostatic sensor is more sensitive to dilute pulverized coal and the capacitive sensor is more sensitive to biomass particles, both sensor techniques are integrated for the concentration measurement of biomass and pulverized coal in biomass/coal/air three-phase flow. First, the flow regime is identified through the Hilbert marginal spectrum of the electrostatic sensor output signal. Then, under certain identified flow regimes, the dual regression analysis method is applied to work out the biomass concentration and the pulverized coal concentration. The experimental result indicates that the fiducial error of the system is less than 5%, and the resolution is about 1%.

In the gas/solid two-phase system, solid particles can accumulate a large number of electrostatic charges because of collision, friction and separation between particles or between particles and the wall. Through the detection and processing of the induced fluctuation charge signal, a measuring system can obtain two-phase flow parameters, such as flow regime, concentration and velocity. A novel methodology via introducing the characteristics of speech emotion recognition into flow regime identification is proposed for improving the recognition rate in gas/solid two-phase flow systems. Three characteristics of electrostatic fluctuation signals detected from an electrostatic sensor are extracted as the input of back propagation (BP) neural networks for flow regime identification. They are short-term average energy, Mel-frequency cepstral coefficients (MFCC) and cepstrum. The results show that the method based on each characteristic of the electrostatic fluctuation signal and BP neural networks can identify the three flow regimes of gas/solid two-phase flow in a horizontal pipe, and the identification rate of the method based on the three characteristics and BP neural networks is up to 97%, much higher than the methods based on a single characteristic.

Cannabis elicits its mood-enhancing and analgesic effects through the cannabinoid receptor 1 (CB1), a G protein coupled receptor (GPCR) that signals primarily through the adenylyl cyclase-inhibiting heterotrimeric G protein G(i). Activation of CB1-G(i) signaling pathways holds potential for treating a number of neurological disorders, and is thus crucial to understand the mechanism of G(i) activation by CB1. Here we present the structure of the CB1-G(i) signaling complex bound to the highly potent agonist MDMB-Fubinaca (FUB), a recently emerged illicit synthetic cannabinoid infused in street drugs that have been associated with numerous overdoses and fatalities. The structure illustrates how FUB stabilizes the receptor in an active state to facilitate nucleotide exchange in G(i). The results compose the structural framework to explain CB1 activation by different classes of ligands and provide insights into the G protein coupling and selectivity mechanisms adopted by the receptor.

The methylation of histone 3 lysine 4 (H3K4) is carried out by an evolutionarily conserved family of methyltransferases referred to as complex of proteins associated with Set1 (COMPASS). The activity of the catalytic SET domain (su(var)3-9, enhancer-of-zeste, and trithorax) is endowed through forming a complex with a set of core proteins that are widely shared from yeast to humans. We obtained cryo-electron microscopy (cryo-EM) maps of the yeast Set1/COMPASS core complex at overall 4.0- to 4.4-Å resolution, providing insights into its structural organization and conformational dynamics. The Cps50 C-terminal tail weaves within the complex to provide a central scaffold for assembly. The SET domain, snugly positioned at the junction of the Y-shaped complex, is extensively contacted by Cps60 (Bre2), Cps50 (Swd1), and Cps30 (Swd3). The mobile SET-I motif of the SET domain is engaged by Cps30, explaining its key role in COMPASS catalytic activity toward higher H3K4 methylation states.

article Experiments have been performed on 1 MW pulverized coal (pc) furnace in order to investigate the characteristics of coal combustion and NOx emission from a new type of radially biased dual register whirl burner. The burner is characterized by a primary air pipe with a continuously changing cross-section and an impact ring. The mixture of pulverized coal and air inside the primary pipe is split into two streams, which are the outer pc rich annular jet and the inner pc lean annular jet respectively. Three Chinese coals, which are high rank bituminous coal, low rank bituminous coal and meager coal respectively, are used in the experiments. We examine the influences of various parameters such as the relative position of the over-fire air (OFA) nozzle, over-fire air ratio (19.1%), primary air ratio, inner secondary air ratio, outer secondary air ratio, inner secondary air swirling intensity, and outer secondary air swirling intensity on NOx formation and unburned carbon in fly ash. With the primary air ratio increasing from 13.4% to 23.4%, the value of the NOx emission of the SH coal decreases by 26.7% at first, and then increases by 21.7%. In contrast, the value of the carbon in fly ash (CFA) increases by 40.1% at first, and then decreases by 58.3%. According to the experimental results, the influence of each individual parameter on NOx formation and unburned carbon in fly ash agrees well with the existing literature. In this study, the influences of various combinations of these parameters are also examined, thus providing some reference for the design of the radial biased whirl burner, the configuration of the furnace and the distribution of the air.

In this study, the effect of hydrogen on methane combustion characteristic was tested. The ignition temperature ( T 10 ) and burn off temperature ( T 90 ) was carried out in a quartz reactor at atmospheric pressure with the mixture flow rate of 800 mL/min. The compositions of outlet gas were measured online by Gasmet DX4000 FTIR gas analyzer. The results showed that hydrogen enhanced the activity of methane. For all methane concentration range, the T 10 of methane could decrease 50 °C–70 °C with the H 2 /CH 4 mole ratio at 0.1. For 1 vol.% methane combustion, when the H 2 /CH 4 was equal to 0.05, the T 10 and T 90 could decrease 45 °C and 42 °C, respectively. When the H 2 /CH 4 was 2.5, the T 10 and T 90 could decrease about 170 °C and 180 °C, respectively. Further more, CO generated in a wider temperature range when the hydrogen was added.

This paper deals with an experimental study on the influence of coal reburn on NOx reduction efficiency, unburned carbon in fly ash and the furnace temperature distribution along the height in a 1 MW (heat input power) tangentially firing furnace with multiple low NOx control technologies. Several variables associated with the reburn system have been investigated in the experiment which includes the air stoichiometry in reburn zone, the location of reburn burner and reburn coal fineness. The optimum location of reburn nozzles has been found where NOx reduction efficiency is highest. With the decrease of reburn coal size (average diameter from 53.69 l mt o 11.47 lm), NOx reduction efficiency increases slightly, but the burnout performance of coal is improved noticeably. In the process of coal reburning, the temperature of flue gas is 70–90 C lower in primary combustion, but 130–150 C higher at the top of furnace as compared to baseline. 2006 Elsevier Ltd. All rights reserved.

A novel capacitive system for the concentration measurement of gas–solid flow in pneumatically conveyed pulverized fuel at power stations has been developed. The capacitance sensor for measuring the concentration uses source-grid sensing electrodes. An active sensor and a dummy sensor are used to form a differential configuration. In order to eliminate baseline drift, to be immune to stray capacitance, and to ensure accurate measurement under very low solids/air mass flux ratio conditions, a correlated double sample (CDS) technique and lock-in detector with closed loop are used in the interface circuit. A laboratory scale pneumatically conveyed pulverized fuel loop system incorporating facilities for calibration has been fabricated for this purpose. The test section is a vertical ceramic tube of diameter 100 mm with an upward flow direction and pulverized fuel has been used as the solid phase. Results demonstrate that the system is capable of achieving linearity within ±5% at different temperatures or moisture content.

A novel high-accuracy and high-speed interface circuit based on lock-in detector is presented for differential-capacitance transducer. In the interface, the feedback capacitance rather than feedback resistance is used in the current detector to reduce the noise due to large resistance. Capacitor–array circuit proposed makes possible to cover a wide range of capacitance changes by choosing feedback capacitor close to the measurand, which results in transfer coefficient of the current sensing circuit about −1. A precision full-wave rectifier based on phase-sensitive-detector (PSD) incorporated in demodulator eliminates the effect due to threshold voltage of diode to improve the accuracy and suppress noise. A second-order low-pass filter is incorporated in demodulator, which allows high-speed and high-accuracy interface for differential-capacitance transducers. Moreover, the circuit is immune to parasitic capacitance, resistances and exciting source. It is capable of detecting the capacitance change as small as 0.005% of the total capacitance up to 16 pF with the speed higher than 5 ksps. A capacitance diaphragm pressure transducer and a standard pressure source (RUSCA 2465 piston gauge) are connected to the circuit to confirm the analysis.

Plants possess very large numbers of biosynthetic cytochrome P450 enzymes. In spite of the importance of these enzymes for the synthesis of bioactive plant secondary metabolites, only two plant P450 structures has been obtained to date. Isoflavone synthase (IFS) is a membrane-associated cytochrome P450 enzyme catalyzing the entry-point reaction into isoflavonoid biosynthesis. IFS from the model legume Medicago truncatula (CYP93C20) was engineered by deleting the membrane-spanning domain and inserting a hydrophilic polypeptide in the N-terminus and a four histidine tag at the C-terminus. The truncated form exhibited dramatically enhanced expression and solubility. The engineered enzyme was expressed in Escherichia coli XL1-blue cells and was purified by Ni(2+)-NTA affinity chromatograph and size-exclusion chromatograph. The purified enzyme was characterized by enzyme assay, reduced carbon monoxide difference spectroscopy and peptide mass fingerprinting. The engineered soluble enzyme exhibited the same activity as the full length membrane-associated enzyme expressed in yeast. These studies suggest an approach for engineering plant membrane-associated P450s with enhanced expression and solubility for mechanistic and structural studies.