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[Objective] To understand the effect of nitrogen application on dry matter accumulation and allocation dynamics in broomcorn millet. [Method] The accumulation and distribution of dry matter were studied using cultivars Jin Shu 7 and Huang Mizi at different levels of nitrogen fertilizer at the jointing stage. [Result] The results showed that increasing N application led to the increase of green leaf area and the delay of leaf senescence, which was beneficial to the accumulation of dry matter. Appropriate nitrogen application (90 kg/hm2) could coordinate the translocation rate of dry matter among different plant parts, thereby enhancing the yield of broomcorn millet; among different organs, the contribution rate of stem to kernel was greater than that of leaf to kernel; there was obvious correlation between dry matter and yield. For Jin Shu 7, leaf area and dry weight of spike showed significant negative correlation with yield. [Conclusion] The formation of grain yield of broomcorn millet involved the accumulation and allocation of dry matter, the appropriate amount of nitrogen application (90 kg/hm2) could improve the rates of translocation and contribution of dry matter, thereby promoting the yield of broomcorn millet. [ABSTRACT FROM AUTHOR]

In a circulating fluidized bed (CFB) with an external heat exchanger (EHE) and a pneumatically controlled loop seal, it is important to measure the gas-solids flow in the loop seal and EHE, for high combustion efficiency. For this purpose, electrical capacitance tomography (ECT) has been applied. Two circular ECT sensors with eight electrodes each are mounted in the two exports of the pneumatically controlled loop seal to monitor the solids flow in the "cold" CFB system. Dynamics tests with different operating conditions were carried out. 2D and 3D images of the cross sections of the exports were reconstructed. The ECT results are analyzed with the pressure drop. The power spectral density (PSD) of signals is obtained by Welch's method and wavelet decomposition in the time domain is implemented for capacitance signals with different conditions. The experimental result indicates that the gas-solids flow can be controlled by pneumatically controlled loop seal based on ECT and pressure drop measurements. [ABSTRACT FROM AUTHOR]

The aim of this research is to investigate the unique shape (concentric-annulus) electrical capacitance tomography (ECT) sensors. This is motivated by the desire to improve the contrast and spatial resolution of the images reconstructed using ECT sensors with internal-external electrodes (IEEs). Both numerical simulation and experimental study were carried out with the goal of providing an improved understanding of the configuration of IEE sensors, the internal shield and the measurement strategies. Simulation results are in agreement with the experimental results. Using the linear back projection algorithm, the IEE sensor with 12 external electrodes and 4 internal electrodes with the external-opposite-internal measurement strategy can reconstruct high-quality images. In experimental studies, the internal shield may reduce the quality of capacitance measured from the internal electrodes. [ABSTRACT FROM AUTHOR]

Bio-fibers have been used for some time to reinforce thermoplastic composites; such structures are being used in a variety of commercial applications. In this study, wood fiber and flax fiber were used to reinforce high-density polyethylene (HDPE) formed by extrusion. The flexural, tensile, and impact resistance properties of the resulting flax fiber/wood fiber/HDPE (F/W/HDPE) composites were measured and modeled as a function of the volume fraction of flax fiber. Finally, the correctness of the modified model was verified. Based on the measurement data, the volume fraction of flax fiber was shown to play an important role in determining the mechanical properties of these composites. With increasing flax fiber volume fraction, the flexural strength, tensile strength, tensile modulus of elasticity, and impact resistance of the composites generally increased. However, the flexural modulus decreased. Based on the rule of mixtures (ROM) model, two coefficients were introduced and a new curve-fitting model was established based on measurements of macrostructure. Compared with the traditional ROM model, the new model developed in the present study could describe the flexural strength, tensile modulus, and impact strength of F/W/HDPE composites more accurately. [ABSTRACT FROM AUTHOR]

Background: 5,10-methylenetetrahydrofolate reductase (MTHFR) variants, C677T and A1298C, have been reported to be associated with decreased risk of acute lymphoblastic leukemia (ALL). However, results derived from individually underpowered studies are conflicting. We carried out an updated meta-analysis on the association between MTHFR polymorphisms and ALL risk. Methods: Relevant publications were searched through PUBMED and EMBASE databases. The associations between MTHFR C677T and A1298C polymorphisms and the risk of ALL were evaluated by odds ratios (ORs). The heterogeneity and publication bias were estimated. Meta-regression analysis was performed to evaluate the potential sources of heterogeneity. Results: C677T polymorphism was associated with a reduced risk of ALL (allele contrast: ORRE = 0.91, 95% CI: 0.83-0.99). Subgroup analysis showed MTHFR C677T variant was associated with decreased susceptibility to ALL in children and Caucasians. Meta-regression showed the logOR for the association between T allele and ALL increased as sex ratio (M/F) in the case group increased (P = 0.01). Regarding A1298C polymorphism, no significant association was observed (allele contrast: ORRE = 1.01, 95% CI: 0.91-1.11). There was no publication bias for C677T or A1298C polymorphism. Conclusions: The present meta-analysis suggests that the C677T polymorphism, not A1298C, in MTHFR gene is associated with a decreased risk of ALL, particularly among children and Caucasians subjects. Our findings suggest that the influence of the C677T polymorphism on ALL susceptibility is modified by sex ratio in cases (M/F). Since folate intake may be a possible confounding factor, including this factor in future prospective studies is warranted. Further meta-analysis studies should be at least stratified for folate levels and gender to give more powerful and informative results. [ABSTRACT FROM AUTHOR]

Left ventricular (LV) dysfunction is a common comorbidity in diabetic patients, although the molecular mechanisms underlying this cardiomyopathic feature are not completely understood. Aldehyde dehydrogenase 2 (ALDH2) has been considered a key cardioprotective enzyme susceptible to oxidative inactivation. We hypothesized that hyperglycemia-induced oxidative stress would influence ALDH2 activity, and ALDH2 inhibition would lead to cardiac functional alterations in diabetic rats. Diabetes was induced by intraperitoneal (i.p.) injection of 60 mg/kg streptozotocin. Rats were divided randomly into four groups: control, untreated diabetic, diabetic treated with N-acetylcysteine (NAC) and diabetic treated with a-lipoic acid (α-LA). Cardiac contractile function, oxidative stress markers and reactive oxygen species (ROS) levels were assessed. ALDH2 activity and expression also were determined. The role of ALDH2 activity in change in hyperglycemia-induced mitochondrial membrane potential (ΔΨ) was tested in cultured neonatal cardiomyocytes. Myocardial MDA content and ROS were significantly higher in diabetic rats than in controls, whereas GSH content and Mn-SOD activity were decreased in diabetic rats. Compared with controls, diabetic rats exhibited significant reduction in LV ejection fraction and fractional shortening, accompanied by decreases in ALDH2 activity and expression. NAC and α-LA attenuated these changes. Mitochondrial ΔΨ was decreased greatly with hyperglycemia treatment, and high glucose combined with ALDH2 inhibition with daidzin further decreased ΔΨ. The ALDH2 activity can be regulated by oxidative stress in the diabetic rat heart. ALDH2 inhibition may be associated with LV reduced contractility, and mitochondrial impairment aggravated by ALDH2 inhibition might reflect an underlying mechanism which causes cardiac dysfunction in diabetic rats. [ABSTRACT FROM AUTHOR]

To optimize the design and operation of a pressurised circulating fluidised bed (PCFB) system, it is necessary to understand the gas–solid flow characteristics and properly measure the solid circulation flux in the cyclone dipleg and loop-seal of the PCFB. In this research, electrical capacitance tomography (ECT) measurement and computational particle fluid dynamic (CPFD) simulation are combined to investigate the multiphase flow behaviour of a ‘cold’ PCFB, in particular the cyclone dipleg. A dual-plane ECT sensor is used for visualisation and online monitoring of the particle distribution. The particle velocity is measured by cross-correlation of two signals from capacitance electrodes, and the circulation flux is analysed. In addition, 3D full-loop CPFD simulation incorporating an energy-minimization multi-scale (EMMS) drag model is performed on a Barracuda platform, to understand the gas–solid hydrodynamic behaviour, validate and supplement the experimental measurements. The results show that the CPFD prediction agrees well with the ECT measurement in terms of the particle volume fraction distribution, velocity and circulation flux. The time-averaged gas–solid flow behaviour, instantaneous hydrodynamic features and the effects of operating pressure on particle distribution and the flow regime in the PCFB dipleg are unravelled. This is the first investigation of a solid circulation flux measurement in the cyclone dipleg and loop-seal of a PCFB system using a combination of ECT measurements, cross-correlation and CPFD simulation with high-pressure operational conditions. [ABSTRACT FROM AUTHOR]

Normally, a gas–solids flow should be non-conductive. With the increase in moisture content in a gas–solids flow, the non-conductive flow may become low-conductive. For the measurement of low-conductive materials, i.e. particles with high moisture content, in the pharmaceutical industry, both electrical capacitance tomography (ECT) and traditional electrical resistance tomography driven by current (ERTc) generate poor images. An ERT driven by voltage (ERTv) may be suitable for the measurement of materials with low-conductivity. In this research, ERTv is used for the measurement of a wet gas–solids flow with different moisture content and different flow patterns, as well as a gas–liquid flow with different flow patterns. In the meantime, ECT is also used for the same flow conditions for comparison. The measurement results of ERTv and ECT are evaluated by the correlation coefficient. The results show that ERTv is good for measurement of a gas–solids flow with high moisture content and a gas–liquid flow when the conductivity of the continuous phase is low or moderate, while ECT is suitable for the measurement of a dry gas–solids flow. [ABSTRACT FROM AUTHOR]

In the design of electrical capacitance tomography (ECT) sensors, the internal wall thickness can vary with specific applications, and it is a key factor that influences the sensitivity distribution and image quality. This paper will discuss the effect of the wall thickness of ECT sensors on image quality. Three flow patterns are simulated for wall thicknesses of 2.5 mm to 15 mm on eight-electrode ECT sensors. The sensitivity distributions and potential distributions are compared for different wall thicknesses. Linear back-projection and Landweber iteration algorithms are used for image reconstruction. Relative image error and correlation coefficients are used for image evaluation using both simulation and experimental data. [ABSTRACT FROM AUTHOR]

Electrical capacitance tomography (ECT) is an imaging technique for measuring the permittivity change of materials. Using a multi-plane ECT sensor, three-dimensional (3D) distribution of permittivity may be represented. In this paper, three excitation strategies, including single-electrode excitation, dual-electrode excitation in the same plane, and dual-electrode excitation in different planes are investigated by numerical simulation and experiment for two three-plane ECT sensors with 12 electrodes in total. In one sensor, the electrodes on the middle plane are in line with the others. In the other sensor, they are rotated 45° with reference to the other two planes. A linear back projection algorithm is used to reconstruct the images and a correlation coefficient is used to evaluate the image quality. The capacitance data and sensitivity distribution with each measurement strategy and sensor model are analyzed. Based on simulation and experimental results using noise-free and noisy capacitance data, the performance of the three strategies is evaluated. [ABSTRACT FROM AUTHOR]

The hydrodynamics of gas–solids flow in the bottom of a circulating fluidized bed (CFB) are complicated. Three-dimensional (3D) electrical capacitance tomography (ECT) has been used to investigate the hydrodynamics in risers of different shapes. Four different ECT sensors with 12 electrodes each are designed according to the dimension of risers, including two circular ECT sensors, a square ECT sensor and a rectangular ECT sensor. The electrodes are evenly arranged in three planes to obtain capacitance in different heights and to reconstruct the 3D images by linear back projection (LBP) algorithm. Experiments were carried out on the four risers using sands as the solids material. The capacitance and differential pressure are measured under the gas superficial velocity from 0.6 m s−1 to 3.0 m s−1 with a step of 0.2 m s−1. The flow regime is investigated according to the solids concentration and differential pressure. The dynamic property of bubbling flows is analyzed theoretically and the performance of the 3D ECT sensors is evaluated. The experimental results show that 3D ECT can be used in the CFB with different risers to predict the hydrodynamics of gas–solids bubbling flows. [ABSTRACT FROM AUTHOR]

Electrical capacitance tomography (ECT) is based on capacitance measurements from electrode pairs mounted outside of a pipe or vessel. The structure of ECT sensors is vital to image quality. In this paper, issues with the number of electrodes and the electrode covering ratio for complex liquid–solids flows in a rotating device are investigated based on a new coupling simulation model. The number of electrodes is increased from 4 to 32 while the electrode covering ratio is changed from 0.1 to 0.9. Using the coupling simulation method, real permittivity distributions and the corresponding capacitance data at 0, 0.5, 1, 2, 3, 5, and 8 s with a rotation speed of 96 rotations per minute (rpm) are collected. Linear back projection (LBP) and Landweber iteration algorithms are used for image reconstruction. The quality of reconstructed images is evaluated by correlation coefficient compared with the real permittivity distributions obtained from the coupling simulation. The sensitivity for each sensor is analyzed and compared with the correlation coefficient. The capacitance data with a range of signal-to-noise ratios (SNRs) of 45, 50, 55 and 60 dB are generated to evaluate the effect of data noise on the performance of ECT sensors. Furthermore, the SNRs of experimental data are analyzed for a stationary pipe with permittivity distribution. Based on the coupling simulation, 16-electrode ECT sensors are recommended to achieve good image quality. [ABSTRACT FROM AUTHOR]

The structure of electrodes in a multi-plane electrical capacitance tomography (ECT) sensor is vital for obtaining high-quality capacitance measurements and good images. In this paper, issues with the relative position of electrodes on each plane in three-plane ECT sensors are discussed. Five ECT sensors with different structures are compared by numerical simulation. For the five sensors, the electrodes on the second and third planes are arranged with rotation angles of 0° and 0°, 0° and 15°, 0° and 30°, 0° and 45°, and 22.5° and 45°, respectively, relative to the electrodes on the first plane. The capacitance data obtained from different sensors by numerical simulation are used for image reconstruction using linear back projection and Landweber iteration algorithms. The image quality is evaluated quantitatively in terms of image error. The sensitivity distributions of all the ECT sensors are compared. The effect of the rotation angles of electrodes on the stability of measured capacitance and on the image quality is also evaluated by experiment. The main conclusion is that the electrodes with no rotation angle should be chosen. [ABSTRACT FROM AUTHOR]

To improve the image quality and reduce the computational cost for electrical capacitance tomography (ECT), a sparsity reconstruction algorithm based on a modified Landweber iteration is presented in this paper. A soft-thresholding function is constructed for permittivity distributions with a continuous phase of low and high permittivity, respectively. An optimal step length is used during the iterative image reconstruction process. The effect of the regularization parameter, the noise level in data, and the permittivity distribution on the performance of the proposed algorithm is discussed according to the correlation coefficient. The modified Landweber iteration with a zero regularization parameter is also implemented for comparison. Simulation and experimental studies were carried out and the corresponding computational costs were estimated, showing the sparsity reconstruction outperforms the Landweber iteration. [ABSTRACT FROM AUTHOR]

The interest using novel drug delivery systems to improve oral bioavailability of drug with poor solubility is increasing. In this study, a new oral delivery system, polybutylcyanoacrylate nanoparticles (PBCNs), was introduced to improve the oral bioavailability of puerarin (PUE). PUE-loaded PBCN was successfully prepared by anionic polymerization method. Characterization of PUE-loaded PBCN was evaluated with morphology, size, zeta potential, and in vitro release study. The PBCN loading PUE exhibited a spherical shape under transmission electron microscopy with an average size of 159.4 nm, and the zeta potential was -15.0mV. The in vitro release of PUE-loaded PBCN showed an initial burst release followed by a sustained release. Physicochemical state of PUE in PBCN was investigated by differential scanning colorimetry, X-ray diffraction, and Fourier transform infrared spectroscopy. The results indicated that PUE in PBCN was in a noncrystalline state. The oral pharmacokinetic study in rats showed that the relative bioavailability of PUE-encapsulated PBCN to the crude PUE was more than 550%. It can be concluded that PBCN as an oral drug carrier can significantly improve the oral bioavailability of PUE. [ABSTRACT FROM AUTHOR]