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The effective plugging of artificial fractures is key to the success of temporary plugging and diverting fracturing technology, which is one of the most promising ways to improve the heat recovery efficiency of hot dry rock. At present, how temporary plugging agents plug artificial fractures under high temperature remains unclear. In this paper, by establishing an improved experimental system for the evaluation of temporary plugging performance at high temperature, we clarified the effects of high temperature, injection rate, and fracture width on the pressure response and plugging efficiency of the fracture. The results revealed that the temporary plugging process of artificial fractures in hot dry rock can be divided into four main stages: the initial stage of temporary plugging, the bridging stage of the particles, the plugging formation stage, and the high-pressure dense plugging stage. As the temperature increases, the distribution distance of the temporary plugging agent, the number of pressure fluctuations, and the time required for crack plugging increases. Particularly, when the temperature increases by 100 °C, the complete plugging time increases by 90.7%. [ABSTRACT FROM AUTHOR]

A new species of Diogenes Dana, 1851, Diogenes bispinatus sp. nov., is described from the South China Sea. It is closely allied to Diogenes dorotheae Morgan & Forest, 1991 and D. patae Asakura & Godwin, 2006, but it morphologically differs from the latter in the length of the antennular peduncle, the number of spines on the ocular acide, the shape of the antennal acide and the number of spines, the shape of the palm of left cheliped and telson. A key to the species of Diogenes from China seas is provided. [ABSTRACT FROM AUTHOR]

Background Cardiac dysfunction in diabetic cardiomyopathy may be associated with abnormal Ca2+ homeostasis. This study investigated the effects of alterations in Ca2+ homeostasis and sarcoplasmic reticulum Ca2+-associated proteins on cardiac function in the development of diabetic cardiomyopathy. Methods Sprague-Dawley rats were divided into 4 groups (n = 12, each): a control group, and streptozotocin-induced rat models of diabetes groups, examined after 4, 8, or 12 weeks. Evaluations on cardiac structure and function were performed by echocardiography and hemodynamic examinations, respectively. Cardiomyocytes were isolated and spontaneous Ca2+ spark images were formed by introducing fluorescent dye Fluo-4 and obtained with confocal scanning microscopy. Expressions of Ca2+-associated proteins were assessed by Western blotting. Results Echocardiography and hemodynamic measurements revealed that cardiac dysfunction is associated with the progression of diabetes, which also correlated with a gradual but significant decline in Ca2+ spark frequency (in the 4-, 8- and 12-week diabetic groups). However, Ca2+ spark decay time constants increased significantly, relative to the control group. Expressions of ryanodine receptor 2 (RyR2), sarcoplasmic reticulum Ca2+-2ATPase (SERCA) and Na +/Ca 2+ exchanger (NCX1) were decreased, together with quantitative alterations in Ca2+regulatory proteins, FKBP12.6 and phospholamban progressively and respectively in the diabetic rats. Conclusions Ca2+ sparks exhibited a time-dependent decay with progression of diabetic cardiomyopathy, which may partly contribute to cardiac dysfunction. This abnormality may be attributable to alterations in the expressions of some Ca2+-associated proteins. [ABSTRACT FROM AUTHOR]

Presents a study which reported a space-time adaptive processing (STAP) approach using the multiple-beam and multiple Doppler channels for airborne phased array radar. Method used in realizing the adaptivity of STAP processor to the nonhomogenous clutter environments; Performance of STAP in an Earth-clutter environment.

The differential quadrature (DQ) element method proposed by Wang and Gu in 1997 has been extended to analyse rectangular plate problems. The methodology is worked out in detail and some numerical examples are given. Copyright © 1998 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Purpose ? It is well known that precision of mass unbalance measurement of sphere is determined by perturbing moments in contactless suspension systems. Therefore, estimating perturbing moment level in those systems is important and necessary to meet the requirements of a specified precision of mass unbalance measurement. Design/methodology/approach ? In this paper, probability-theoretic method is employed to determine probability characteristics of the perturbing moments in both electrostatic suspension system and gas suspension system by statistically estimating of the quality of sphere surface. As a result, the relationship between probability characteristics of the perturbing moment and statistical estimates of the quality of sphere surface is established. It is expressed as a simple formula by specifying the correlation function of random field of sphere surface. Findings ? Numerical experiments of the perturbing moment calculation in the two suspension systems show that for sphere with small correlation coefficient a, it is better to use gas suspension system for mass unbalance measurement. While for sphere with large correlation coefficient a, electrostatic suspension system is more suitable for its perturbing moment are less than gas suspension system. Originality/value ? Knowledge of this relationship is of great theoretic and practical importance, since the probabilistic depiction of the perturbing moments, and hence the accuracy of the mass unbalance measurement systems can be estimated without a detailed roundness measurement of the sphere surface. [ABSTRACT FROM AUTHOR]

High-voltage amplifiers as a means of amplifying the low-output voltage signals of the feedback controllers to the suspension voltages typically in the kilovolts range are often required for electrostatic force generation in electrostatic levitation. This paper proposes a high-voltage dc amplifier including an amplitude modulator, a power amplifier, a step-up transformer, a pair of peak detectors, and a voltage feedback channel to stabilize the amplifier outputs in an effort to provide high suspension voltage and fast dynamic response. Since the various carrier frequencies have virtually no effect on the power consumption of the dc amplifier by filtering out the high-frequency carrier components with peak detectors while keeping the input signal unaffected, satisfactory dynamic performance can be achieved by choosing a sufficiently high carrier frequency. The operating principle of the dc amplifier is analyzed, followed by an experimental performance evaluation and discussion for electrostatic levitation applications. The experimental results demonstrate the superiority of the high-voltage dc amplifier over classical ac amplifiers in terms of dynamic response, force-voltage coefficient, voltage ripple, power consumption, and long-time stability using a carrier frequency of 30 kHz and the closed-loop control scheme. [ABSTRACT FROM AUTHOR]

Obesity and related metabolic disorders are associated with intestinal microbiota dysbiosis, disrupted intestinal barrier, and chronic inflammation. Neohesperidin (Neo), a natural polyphenol abundant in citrus fruits, is known for its preventative and therapeutic effects on numerous diseases. Here, we report that Neo administration attenuates weight gain, low-grade inflammation, and insulin resistance in mice fed high-fat diet (HFD). Also, Neo administration substantially restores gut barrier damage, metabolic endotoxemia, and systemic inflammation. Sequencing of 16S rRNA genes in fecal samples revealed that Neo administration reverses HFD-induced intestinal microbiota dysbiosis: an increase in the diversity of gut microbiota and alteration in the composition of intestinal microbiota (particularly in the relative abundances of Bacteroidetes and Firmicutes). Furthermore, systemic antibiotic treatment abolishes the beneficial effects of Neo in body weight control, suggesting that the effect of Neo on obesity attenuation largely depends on the gut microbiota. More importantly, we demonstrate that the impact of Neo on the regulation of obesity could be transferred from Neo-treated mice to HFD-fed mice via fecal microbiota transplantation. Collectively, our data highlight the efficacy of Neo as a prebiotic agent for attenuating obesity, implying a potential mechanism for gut microbiota mediated the beneficial effect of Neo. [ABSTRACT FROM AUTHOR]

Fetal magnetocardiography (MCG) is a sophisticated non-invasive technique for the fetal heart diagnosis. We constructed a multichannel fetal MCG system based on a novel superconducting quantum interference device (SQUID) direct readout scheme called SQUID bootstrap circuit (SBC). The system incorporates four SBC gradiometers for the signal detection and three SBC magnetometers as the references. The fetal MCG signal at a 28-weeks' gestation was measured. By the fetal MCG signal separation and average, the P-wave and QRS complex can be clearly identified. These results indicate that the SBC is one of the most promising techniques for the fetal MCG recordings. [ABSTRACT FROM AUTHOR]

For along-track multichannel synthetic aperture radar, this paper proposes a novel ground moving target signal model in the high-resolution complex image domain. Based on the range-Doppler imaging of static scene, the 2-D complex response of an isolated rectilinearly moving target is derived via the stationary phase principle (SPP) approximations. It is shown that moving targets in complex domain can be divided into three types according to the 2-D motion distribution and the SPP approximation conditions. Different from the known peaklike response of a static target, different amplitude and phase modulations will appear for different types of moving targets. Moreover, a single target can be split into two targets in the image when its Doppler spectrum spreads over two ambiguous Doppler zones. All types of targets will have the same Doppler interferometric effect along multichannel images, which is decided by the target's ambiguous Doppler frequency. Furthermore, with the proposed signal model, the complex image properties can be completely described and analyzed. Finally, some numerical experiments are also provided to demonstrate the effectiveness of the proposed signal model and analysis. [ABSTRACT FROM AUTHOR]

Based on a parametric model and some optimum methods, it has been previously proved that parametric velocity synthetic aperture radar (VSAR) may improve the performances of moving target detection and parameter estimation simultaneously. In this paper, multilook processing is studied for parametric VSAR. At first, statistical signal models are established for azimuth multilook processing (AMLP) and range multilook processing (RMLP), respectively. By combining the multiple AMLP sublook pixel vectors, it is shown that the clutter parameter estimation accuracy can be further improved via the maximum- likelihood estimation methods. Meanwhile, based on the adaptive implementation for the optimum processing of VSAR, RMLP can be used to improve slowly moving target detection performance via the noncoherent integration of multiple range sublooks. Furthermore, it is shown that the Doppler frequencies of moving targets vary linearly with different range sublooks due to the different carrier frequencies of sublooks. Therefore, based on a proposed novel two-step multilook diversity (TS-MLD) estimator for RMLP, the "azimuth location ambiguity" of VSAR can be well resolved via least squares linear regression, without configuration change of the conventional VSAR. Also, the estimation accuracy of target's unambiguous Doppler frequency, as well as target's azimuth location, is derived for the proposed TS-MLD method. Finally, numerical experiments and scene simulations are provided to demonstrate the effectiveness of the proposed multilook-based methods. [ABSTRACT FROM AUTHOR]

Velocity synthetic aperture radar (VSAR) is equipped with a linear array to receive the echoes from a radar illuminating area via multiple channels, each of which can reconstruct a reflectivity image for the same stationary scene. Based on analysis of pixel vector sampled among multi-images, VSAR may effectively suppress the strong ground clutter and improve moving target detection and location. In this paper, different Doppler-distributed properties are derived for the moving target and clutter, respectively. Then, we propose a novel parametric statistical model for VSAR by dividing the pixel vector into three components, namely, target, clutter, and noise. Furthermore, a method of adaptive implementation of optimal processing (AIOP-VSAR) is presented for moving target detection. It is shown that the optimum detection performance may be obtained via AIOP-VSAR, particularly for the slowly moving target in an inhomogeneous clutter environment. Also, the Cramer-Rao bounds (CRBs) are derived for the estimation of unknown model parameters, as well as the azimuth locations of moving targets, and the maximum-likelihood methods are proposed to reach these CRBs. Based on the proposed target detection and parameter estimation methods, we present a complete parametric flowchart for VSAR. It is demonstrated that the proposed flowchart may effectively mitigate the "azimuth location ambiguity" of VSAR and has the super-resolution ability to resolve "velocity layover" for multiple targets. Finally, some detailed numerical experiments and scene simulations are provided to show the effectiveness of the proposed methods. [ABSTRACT FROM AUTHOR]

A dual-washer superconducting quantum interference device (SQUID) with a loop inductance of 350 pH and two on-washer integrated input coils is designed according to conventional niobium technology. In order to obtain a large SQUID flux-to-voltage transfer coefficient, the junction shunt resistance is selected to be 33 Ω. A vertical SQUID gradiometer module with a baseline of 100 mm is constructed by utilizing such a SQUID and a first-order niobium wire-wound antenna. The sensitivity of this module reaches about 0.2 fT/(cm·Hz1/2) in the white noise range using a direct readout scheme, i.e., the SQUID is directly connected to an operational amplifier, in a magnetically shielded room. Some magnetocardiography (MCG) measurements with a sufficiently high signal-to-noise ratio (SNR) are demonstrated. [ABSTRACT FROM AUTHOR]

The begomoviruses are the largest and most economically important group of plant viruses transmitted exclusively by the whitefly Bemisia tabaci in a circulative, persistent manner. The circulation of the viruses within the insect vectors involves complex interactions between virus and vector components; however, the molecular mechanisms of these interactions remain largely unknown. Here we investigated the transcriptional response of the invasive B. tabaci Middle East-Asia Minor 1 species to Tomato yellow leaf curl China virus (TYLCCNV) using Illumina sequencing technology. Results showed that 1,606 genes involved in 157 biochemical pathways were differentially expressed in the viruliferous whiteflies. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that TYLCCNV can perturb the cell cycle and primary metabolism in the whitefly, which explains the negative effect of this virus on the longevity and fecundity of B. tabaci. Our data also demonstrated that TYLCCNV can activate whitefly immune responses, such as autophagy and antimicrobial peptide production, which might lead to a gradual decrease of viral particles within the body of the viruliferous whitefly. Furthermore, PCR results showed that TYLCCNV can invade the ovary and fat body tissues of the whitefly, and Lysotracker and Western blot analyses revealed that the invasion of TYLCCNV induced autophagy in both the ovary and fat body tissues. Surprisingly, TYLCCNV also suppressed the whitefly immune responses by downregulating the expression of genes involved in Toll-like signaling and mitogen-activated protein kinase (MAPK) pathways. Taken together, these results reveal the relationship of coevolved adaptations between begomoviruses and whiteflies and will provide a road map for future investigations into the complex interactions between plant viruses and their insect vectors. [ABSTRACT FROM AUTHOR]