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Background: Despite the clear clinical diagnostic criteria for necrozoospermia in andrology, the fundamental mechanisms underlying it remain elusive. This study aims to profile the lipid composition in seminal plasma systematically and to ascertain the potential of lipid biomarkers in the accurate diagnosis of necrozoospermia. It also evaluates the efficacy of a lipidomics-based random forest algorithm model in identifying necrozoospermia. Methods: Seminal plasma samples were collected from patients diagnosed with necrozoospermia (n = 28) and normozoospermia (n = 28). Liquid chromatography–mass spectrometry (LC–MS) was used to perform lipidomic analysis and identify the underlying biomarkers. A lipid functional enrichment analysis was conducted using the LION lipid ontology database. The top 100 differentially significant lipids were subjected to lipid biomarker examination through random forest machine learning model. Results: Lipidomic analysis identified 46 lipid classes comprising 1267 lipid metabolites in seminal plasma. The top five enriched lipid functions as follows: fatty acid (FA) with ≤ 18 carbons, FA with 16–18 carbons, monounsaturated FA, FA with 18 carbons, and FA with 16 carbons. The top 100 differentially significant lipids were subjected to machine learning analysis and identified 20 feature lipids. The random forest model identified lipids with an area under the curve > 0.8, including LPE(20:4) and TG(4:0_14:1_16:0). Conclusions: LPE(20:4) and TG(4:0_14:1_16:0), were identified as differential lipids for necrozoospermia. Seminal plasma lipidomic analysis could provide valuable biochemical information for the diagnosis of necrozoospermia, and its combination with conventional sperm analysis may improve the accuracy and reliability of the diagnosis. [ABSTRACT FROM AUTHOR]

This paper proposes a time‐domain fitting method for on‐site calibration of the air‐coil sensor. The air‐coil sensor has been widely used in transient electromagnetic exploration. Due to limited bandwidth of the coil, the output signal is distorted, causing a phenomenon known as the transition process. To accurately measure the magnetic field from the output signals, the relationship between the coil induced electromotive force and the output voltage must be confirmed by on‐site calibration, which requires high calibration accuracy and demands simple operation, portable equipment, and adaptability to the environment. Conventional frequency response methods, however, requires a uniform magnetic field with various frequencies to obtain the frequency response curve of the air‐coil sensor. The time to acquire the signal correlates with the number of test frequencies, and the equipment used to generate a uniform magnetic field must be tailored to the shape of the air‐coil sensor under test. This paper constructs a relationship between the calibration file and the zero‐input response of the air‐coil sensor and designs an optimization algorithm to suppress the soil eddy current effect. This on‐site calibration method lifts the dependence on the uniform calibration field and reduces significantly the time required for calibration. The calibration source can be generated by cutting off the voltage source in parallel to the calibration coil, which greatly reduces the cost of the signal generator and provides a better solution for realizing the embedded self‐test devices. Experimental results show that the proposed method effectively improves the calculation accuracy of the apparent resistivity. [ABSTRACT FROM AUTHOR]

• The proposed calibration scheme saves time for signal acquisition. • Only need to collect the output signal to complete the calibration of the device. • High calibration accuracy and controllable error by feedback signal. An air-coil sensor (ACS) is a type of induction magnetometer used to measure the variation of a magnetic field. Due to the limited bandwidth of the coil, its output signal is distorted, a phenomenon known as the transition process. To measure the magnetic field accurately, the relationship must be confirmed by calibration. However, conventional methods require a uniform magnetic field with various frequencies to ensure the induced electromotive force is controllable. The time taken to acquire the signal correlates with the number of test frequencies, and the equipment used to generate the uniform magnetic field must be tailored to the shape of the ACS under test. This paper proposes a time-domain feedback calibration method for ACS to avoid the above constraints. An algorithm is applied to relieve the dependence of the calibration file on the input signal, so that the calibration file will not be affected by the calculation error of the input signal nor be limited by the uniform magnetic field, and the accuracy of the calibration file can be evaluated by the feedback signal. The exponential current, which contains a variety of frequency components, is selected as the calibration signal to shorten the time of data collection. The equipment used to generate the calibration signal is simple, which is suitable for on-site calibration. The scheme can be used for rapid calibration of various air-core coils, and provides a better solution for realizing embedded self-test of ACS. [ABSTRACT FROM AUTHOR]

A wavelet edge detection method is introduced to image the topology of grounding grids and locate the grounding conductors from measured magnetic induction. Theoretical analysis of the magnetic field and calculation method of discrete wavelet transform are described. Since the sharpest variation of the magnetic field perpendicular to the ground surface occurs right above a conductor, the gradient vector modulus maximum of the vertical component can be calculated to extract the position information about the conductor. This scheme is derived from the Canny edge detection. A 2-D discrete à trous algorithm is used to perform equivalent edge detection as the wavelet transform avoids partial derivative. The method is robust to noise and would extract more stable and distinct edge. Extensive simulation and experimental examples demonstrate that the proposed method can accurately draw the topology of grounding grids and locate the conductors. [ABSTRACT FROM AUTHOR]

Optimizing the grounding grid configuration is an effective approach to improve the performance of grounding grid. On the other hand, configuration of grounding grid is necessary for some defect diagnosis method to detect the faults existing in grounding conductors. This paper employs the transient electromagnetic (TEM) method to draw the configuration of a substation grounding grid. The surface magnetic field is recorded by receiver coils above the grounding grid. Based on the regular distribution characteristics of a recorded magnetic field, the grounding conductor is accurately located from the curve of magnetic intensity. The complete process of configuration detection of the grounding grid is described in detail. After fast inversion calculation of the recorded magnetic field, the equivalent resistivity is obtained. The configuration of the grounding grid will be clearly and accurately shown in the contour map and three-dimensional (3-D) surface map of equivalent resistivity. Model study is performed, and a field test is also conducted. The results are in good agreement to demonstrate the effectiveness of TEM method for configuration detection of the substation grounding grid. [ABSTRACT FROM AUTHOR]

Faults in the grounding grid are a hidden danger to the safety of power systems and cause significant economic loss every year. This paper presents a new means to locate faults in grounding grids using the transient electromagnetic imaging method. The method compares the distribution characteristics of the equivalent resistivity of the underground covered by grids for the no-fault case and those with break points. We describe why and how the proposed method can be used for the break-point diagnosis of grounding grids. Simulation was performed using the Ansoft finite-element method package, and a field experiment was conducted to verify the effectiveness of the proposed method. This study provides a practical means for break-point diagnosis with no requirement of power shut down or soil excavation. Moreover, the proposed method does not require the design drawings of grounding grids. [ABSTRACT FROM PUBLISHER]

Faults of grounding grids are threat to the safety of power system and cause significant economic loss every year in China. Accurate detection of the faults will alleviate these detrimental effects. This paper presents a novel approach using the transient electromagnetic method for fault diagnosis of grounding grids. The induced magnetic intensity is collected by receiver coils in the form of electromotive force. After inversion calculation, the contour map of equivalent resistivity of underground covered by grids is obtained. The faults due to corrosion or break can be accurately located from the distribution characteristics of equivalent resistivity maps. The influence of the fault of different degrees, material of grounding conductor, and soil resistivity on distribution of induced magnetic intensity to fault diagnosis will be analyzed in detail. The effect of the underground pipeline on fault diagnosis of grounding grids is also investigated. Simulation was performed, and a field experiment was conducted to verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Service lifetime estimation for earth grounding grids as a problem or a task faced by the industry is presented. A mathematical model based on Freschi's semianalytical model to determine the performance of the earth grounding grid at a certain year after being buried is proposed. The mathematical model can also explain the performance degradation of the earth grounding grid in principle and mathematically. According to the model, a scheme to estimate the service life of the earth grounding grid is proposed. A case study is given to illustrate how the scheme works. If the estimated service life of an earth grounding grid is not satisfactory, some measures, such as cathodic protection, should be considered to extend the service lifetime of the earth grounding grid. [ABSTRACT FROM AUTHOR]

ABSTRACT Distributed parameters of the receiver coils greatly affect transient electromagnetic signals over short time periods, causing a delay in the signal's effective sampling time and the loss of shallow exploration information. This paper investigates the influence of transient process on apparent resistivity calculation and analyses the relations between the error of apparent resistivity and receiver coil design. We find that, under the same effective area, different radii of the receiver coils lead to different levels of impact on the estimation of the apparent resistivity. An optimization model is proposed to determine the optimal receiver coil size that gives rise to the smallest estimation error of the apparent resistivity. The relationship between the optimal radius and the effective areas is developed, which serves as a guideline for the optimal receiver coil design. The results may provide a useful means for improving the accuracy of the small loop transient electromagnetic instrumentation for shallow-depth mapping. [ABSTRACT FROM AUTHOR]

Abstract: MixAlco™ consolidated bioprocessing (CBP) employs a mixed culture of terrestrial microorganisms to anaerobically ferment waste streams (e.g., animal manure, agriculture residues) into mixed carboxylate salts that can be further chemically converted to commodity chemicals (e.g., acetic acid, acetone) and liquid transportation fuels (e.g., ethanol, mixed alcohols, bio-gasoline). For countercurrent fermentations of 60% swine manure/40% lime-treated corn stover at 55 °C, the highest acid productivity [1.8 g/(L·d)] and highest conversion (73%) in this study occurred at an acid concentration of 25.1 and 17.0 g/L, respectively. The continuum particle distribution model (CPDM) predicted the experimental total acid concentrations and conversions around 11.1% and 17.2%, respectively. The CPDM prediction "map" for MixAlco™ CBP indicates that both high conversions (>79%) and high total acid concentrations (>35 g/L) are possible at industrial scale. The present study shows continuous co-digestion of corn stove and swine manure in the MixAlco™ process has the potential to produce annually 9.3 billion gallons of alcohol fuels (e.g., ethanol and mixed alcohols) in the United States. [Copyright &y& Elsevier]

Abstract: Sugarcane trash (ST) was converted to ammonium carboxylates using a novel bioprocessing strategy known as long-term air-lime pretreatment/mixed-culture fermentation. At mild conditions (50°C, 5weeks, 1-atm air, and excess lime loading of 0.4g Ca(OH)2/(g dry biomass)), air-lime pretreatment of ST had moderate delignification (64.4%) with little loss in polysaccharides. Without employing detoxification, sterility, expensive nutrients, or costly enzymes, the feedstock (80% treated ST/20% chicken manure) was fermented to primarily ammonium acetate (>75%) and butyrate by a mixed culture of marine microorganisms at 55°C. In the best four-stage countercurrent fermentation, the product yield was 0.36g total acids/(g VS fed) and the substrate conversion was 64%. Model predictions indicate both high acid concentrations (>47.5g/L) and high substrate conversions (>70%) are possible at industrial scale. [Copyright &y& Elsevier]

Objective: To explore an optimal laser dose of transvaginal ultrasound-guided ovarian interstitial laser coagulation in management of anovulation in patients with polycystic ovary syndrome (PCOS). Design: Randomized, controlled trial. Setting: A reproductive medical center. Patient(s): Eighty women with PCOS and clomiphene citrate-resistant infertility underwent ultrasound-guided transvaginal ovarian interstitial yttrium aluminum garnet laser treatment. All subjects were divided randomly into four groups of A, B, C, and D. Intervention(s): Group A, one coagulation point per ovary; group B, two points; group C, three points; group D, four to five points. Main Outcome Measure(s): Postoperative ovulation rate, pregnancy rate, and some biochemical parameters. Result(s): The rates of ovulation in groups C (75.00%, 95% confidence interval [CI]: 51%-91%) and D (80.00%, 95% CI: 56%-94%) within 6 postoperative months were significantly higher than in groups A (5.00%, 95% CI: 0%-25%) and B (15.00%, 95% CI: 3%-38%). The pregnancy rates in groups C (45.00%, 95% CI: 23%-69%) and D (40.00%, 95% CI: 19%-64%) also were significantly higher than in groups A (5.00%, 95% CI: 0-25%) and B (10.00%, 95% CI: 1%-32%). The mean serum T levels were significantly lower in groups C (2.08 +/- 0.62 nmol/L) and D (2.07 +/- 0.42 nmol/L) compared with groups A (3.10 +/- 0.63 nmol/L) and B (2.95 +/- 0.63 nmol/L). Conclusion(s): One and two intraovarian laser coagulation points per ovary are associated with poor outcomes. Three points per ovary seem to represent the plateau of effective dose for the ovarian interstitial laser treatment in PCOS. [ABSTRACT FROM AUTHOR]

Abstract: The MixAlco process, an example of consolidated bioprocessing (CBP), was utilized for anaerobic fermentation of 80% lime-treated sugarcane bagasse/20% chicken manure at 55°C by a mixed culture of marine microorganisms. NH4HCO3 was recommended by this study to replace CaCO3 buffer to neutralize the produced carboxylic acids. The resulting ammonium carboxylates can be converted to gasoline or mixed alcohol fuels by downstream processing. Four-stage countercurrent fermentations at various volatile solids loading rates (VSLR) and liquid residence times (LRT) showed the highest acid productivity (1.27g/(L·day)) and highest conversion (76%) occurred at a total acid concentration of 24.4 and 31.3g/L, respectively. The Continuum Particle Distribution Model (CPDM) predicted the experimental total acid concentrations and conversions within 9.05% and 14.39%, respectively. The CPDM “map” indicates that both high acid concentrations (>50g/L) and high conversions (>72%) are possible with 300g substrate/(L liquid) concentration, 30 days liquid residence time, 5.4g/(L·day) solid loading rate, and NH4HCO3 buffer. The present study suggests that mixed culture biotechnology in the MixAlco process provides an alternative “carboxylate platform” for biomass conversion. [Copyright &y& Elsevier]

In this article, a novel circuit topology of near rectangular current pulse generation suitable for the transient electromagnetic (TEM) applications is proposed. Satisfactory TEM applications, in general, rely upon a TEM transmitter circuit acting as a current excitation source to produce a high-quality primary magnetic field. This requires that the generated current pulse be of short turn-off delay time, with highly linear falling edge, and fast rising edge. The generation of near rectangular bipolar current pulses is very challenging for high-current high-power applications. The proposed TEM transmitter circuit can be considered as a voltage stabilizing clamp current pulse shaper. Its operation principles are described and guidelines for optimal component selection are also provided. Simulation results show that the proposed circuit demonstrates superior performance compared to other TEM transmitter circuit topologies, such as the improved RCD snubber, IEDD, and the quasi-resonant rectifying circuit. [ABSTRACT FROM AUTHOR]

Economic commercial-scale production of biofuels from lignocellulose depends, in part, on the development of a suitable pretreatment. In pursuit of that goal, this study assesses the repeatability and effectiveness of submerged lime pretreatment (SLP) of two batches of corn stover designated "Field" and "Module." SLP was performed with 0.15 g Ca(OH) 2 g−1 biomass and 10 g H 2 O g−1 biomass at 50 °C for 4 weeks while purging with air. SLP was repeated 14 times and the results of the mass balances, closures, and compositions of raw and SLP corn stover are presented. The glucan content of corn stover prior to pretreatment was determined to be 36.1 ± 0.7% (Module washed), 37.5 ± 0.4% (Field washed), and 32.6 ± 1.4% (Field unwashed). For washed corn stover (Module and Field), the standard deviation and coefficient of variation were <1%, demonstrating that the measurements were repeatable. For unwashed Field corn stover, because of its higher content of water-soluble components, the variability was slightly higher. The mass closures were above 96% with less than 2% standard deviation. The glucan content of SLP corn stover was 44.3 ± 0.8% (Module washed), 41.5 ± 0.5% (Field washed), and 42.9 ± 2.2% (Field unwashed). This study also presents a reliable analytical method for assessing the enzymatic digestibility of high-solids (15%) lignocellulose. Inositol is used as an internal standard to determine the final reactant volume, which is difficult in high-solids saccharification. After SLP, the overall glucan digestibility was ~80% (standard deviation < 4%, coefficient of variation < 5%), supporting the potential of SLP as a reproducible, cost-effective, and scalable pretreatment. • Oxidative submerged lime pretreatment (SLP) of corn stover repeated 14 times to assess repeatability. • Inositol used as an internal standard to estimate final volume of reactants for high-solids saccharification (15% solids). • SLP is a highly repeatable process which increases the glucan content and enzymatic digestibility of corn stover (~80%). [ABSTRACT FROM AUTHOR]

The grounding grid is critical to the safety and stability of a power system. Corrosive cracking of the grounding conductor is the main cause of deterioration of grounding grid performance. Existing fault diagnosis methods for grounding grids are limited by the number and distribution of grounding leads, and some of them cannot be used for online detection. This paper proposes a grounding grid detection method based on magnetic source excitation. The measuring device consists of four coils, two horizontal excitation coils, and two vertical receiving coils. The secondary magnetic field signal is extracted from the primary field and the background field by properly positioning the coils, such that the measured signal can reflect the underground media more accurately. The measuring device of the method is portable, the measurement process is contactless with the grounding grid, and it is not limited by the grounding leads. Furthermore, it has a strong anti-interference ability and can realize online detection. It was proven by simulations and experiments that the proposed method has a higher measurement accuracy and stronger anti-interference ability when compared with existing methods. This paper also discusses the influence of various factors such as the number and the location of the breakpoints, the frequency of the excitation source, the soil resistivity, and stratification from the measurement data. It was proven that the method has high precision and a wide application range, and is important for guiding significance and reference value in engineering applications. [ABSTRACT FROM AUTHOR]

This paper proposes a nondestructive, separate transmitter-receiver (TX-RX) electromagnetic measurement system for near-surface detection. Different from the traditional dual-coil integrated design, the proposed transient electromagnetic (TEM) system performs shallow subsurface detection using independent TX coil and movable RX coils. This configuration requires a large primary field so that the far-away secondary field is able to generate reliably induced voltages. To achieve this goal, a bipolar current-pulsed power supply (BCPPS) with a late resonant charging strategy is designed to produce a sufficiently large magnetic moment for the exciting coil with low source interference. The magnetic dipole source (MDS) with a large proportion of weight is separated from the field observation device and does not need to be dragged or transported during the detection process. This setup lowers the weight of the scanning device to 3 kg and greatly improves the measurement efficiency. The results of the laboratory test verify the effectiveness of the separate MDS and RX module system. Field experimental detection further demonstrates that the proposed system can realize highly efficient and shallow surface detection within a 200 m range of the MDS device. [ABSTRACT FROM AUTHOR]

Aiming at the problem of large measurement error and phase shift in resistance voltage dividers under high-frequency conditions in the field of power measurement, such as power harmonics, an error correction method is proposed for an alternating current (AC) resistance voltage divider based on the equivalence principle. Firstly, the frequency error model of the AC resistance voltage divider precision is established, and the angle difference of the continuous spectrum ratio difference from 50 Hz to 100 kHz is corrected by determining the shielding structure and the resistance parameters and fine-tuning the shielding potential correction method to reduce the capacities error of the AC resistance voltage divider design precision. At the same time, the performance parameters such as the direction and magnitude of the shielding potential compensation capacitive error are investigated. Finally, the precision voltage divider (the maximum voltage applied is 480 V) calibration experiments verify that the important characteristic judgment factor of the voltage divider is independent of the frequency and the equivalent capacitance value, which effectively solves the phase correction problem of harmonic power measurement. [ABSTRACT FROM AUTHOR]

Background: The elevated circulating toxins secondary to the impairment of intestinal barrier integrity commonly elicit a chronic inflammatory response and finally contribute to multiple diseases. These toxins, including bacterial by-products and heavy metals, are the potent risk factors for the development of recurrent spontaneous abortion (RSA). Preclinical evidence suggests that several dietary fibers can restore intestinal barrier function and decrease the accumulation of heavy metals. However, it is uncertain whether treatment with a newly developed blend of dietary fibers product (Holofood) benefits patients with RSA. Methods: In this trial, we enrolled 70 adult women with RSA, who were randomly assigned into the experiment group and the control group in a 2:1 ratio. Upon the basis of conventional therapy, subjects in the experiment group (n = 48) received 8 weeks oral administration with Holofood three times daily at a dose of 10 g each time. Subjects without Holofood consumption were set as the control (n = 22). Blood samples were collected for the determinations of metabolic parameters, heavy mental lead, and the indices related to intestinal barrier integrity (d-lactate, bacterial endotoxin, and diamine oxidase activity). Results: The reduction amplitude in blood lead from baseline to week 8 was 40.50 ± 54.28 (μg/L) in the experiment group as compared with 13.35 ± 36.81 (μg/L) in the control group (P = 0.037). The decreased level of serum d-lactate from baseline to week 8 was 5.58 ± 6.09 (mg/L) in the experiment group as compared with − 2.38 ± 8.90 (mg/L, P < 0.0001) in the control group. The change in serum DAO activity from baseline to week 8 was 3.26 ± 2.23 (U/L) in the experiment group as compared with − 1.24 ± 2.22 (U/L, P < 0.0001) in the control group. Participants who received Holofood had a greater decline in blood endotoxin from baseline to week 8 than those in the control group. Moreover, by comparing with the self-baseline, Holofood consumption significantly decreased the blood levels of lead, d-lactate, bacterial endotoxin, and DAO activity. Conclusion: Our results suggest that Holofood affords a clinically relevant improvements in blood lead level and intestinal barrier dysfunction in patients with RSA. [ABSTRACT FROM AUTHOR]

Early seismic prediction in tunnels has become a necessary task to prevent construction risks. The type and performance of the seismic source are crucial factors that affect its efficiency and prediction accuracy. Among the existing main types of tunnel seismic sources, both explosive and spark sources require pre-drilling and pose safety hazards. In addition, explosive sources pose a risk of damage to tunnel structure walls. Spark sources must be used in a water medium. Artificial hammer sources have weak energy and short prediction distance. This paper proposes a portable tunnel electromagnetic impulse shock source that overcomes the deficiencies of the aforementioned seismic sources. This paper elaborates on the design and working principle of the electromagnetic impulse shock source, and analyzes the electromagnetic force exerted on the hammer body during acceleration. Through finite element simulation, this paper analyzes the multi-physical field changes of the entire electromagnetic acceleration system. Meanwhile, combining experimental testing, the design parameters and energy of the seismic source are optimized to finally design a portable electromagnetic impulse shock source. The engineering measurement data results show that the seismic source can stably generate an output energy of 1500 J, and the overall weight of the seismic source does not exceed 40 kg, with a single shot time less than 30 s and an effective prediction distance over 100 m. This work has significant practical value and superiority. [ABSTRACT FROM AUTHOR]

This article presents a novel design of a bipolar current-pulsed power supply (BCPPS) for shallow electromagnetic detection. Problems of acquiring current pulses with low oscillation and low energy cost are analyzed in detail and relevant solutions are given. An improved topology based on a constant-voltage clamping circuit is proposed to satisfy the demands of supplying the highly inductive load. The relationship between the main steady-state parameters of the proposed BCPPS is provided and the shape of current pulses can be adjusted flexibly by changing the duty cycles of the switching signals in the topology. A feedforward control strategy to realize constant-current transmitting is proposed and the digital controller is designed. Compared with different existing current-pulsed sources, the topology in this article is characterized by high repeat frequency, low energy cost, and low switching interference. A laboratory prototype with a maximum peak current of 50 A and repeat frequency of 500 Hz is built to verify the effectiveness of the proposed topology. [ABSTRACT FROM AUTHOR]

Abstract: Objective: To assess the effectiveness of repeated transvaginal ultrasound-guided ovarian interstitial laser treatment in the management of anovulatory patients with polycystic ovary syndrome (PCOS). Study design: A retrospective study was performed in our department on 27 anovulatory PCOS women who failed to respond to the first ultrasound-guided transvaginal ovarian interstitial laser treatment. Each woman received a repeat procedure and postoperative rates of ovulation and pregnancy were monitored. Results: Of 27 patients, 18 (66.67%) ovulated spontaneously following the repeated ultrasound-guided transvaginal ovarian interstitial laser treatment Ten women became pregnant within six postoperative months and a cumulative pregnancy rate of 37.04% was achieved. There were no significant operative complications. Conclusion: Repeated ultrasound-guided transvaginal ovarian interstitial laser treatment is an effective and safe management in anovulatory PCOS patients who fail to respond or have a transient response to the first transvaginal ovarian interstitial laser treatment. [Copyright &y& Elsevier]

Objective: To evaluate the effectiveness of uterine cavity injection of day 2 embryo culture supernatant before day 3 embryo transfer in patients who are undergoing in vitro fertilization-embryo transfer. Design: Randomized controlled trial. Setting: A reproductive medical centre. Patient(s): A total of 90 infertile women, 45 of them in the study group and 45 in the control group. Intervention(s): Uterine cavity infection of day 2 embryo culture supernatant before day 3 embryo transfer. Main Outcome Measure(s): Embryo implantation rate and pregnancy rate. Result(s): The pregnancy versus implantation rates in the study group and control group were 48.9% versus 44.4% and 27.3% versus 22.1%, respectively. Although both pregnancy and implantation rates in the study group were higher than those in the control group, no statistically significant differences were found in these two parameters. Conclusion(s): Injection of day 2 embryo culture supernatant into the uterine cavity cannot improve the implantation and pregnancy rates of day 3 embryo transfer. [Copyright &y& Elsevier]

Abstract: In this paper, improvement in the method for purifying glycoprotein from green tea (Camellia sinensis) was described; some properties and chemical compositions of tea glycoprotein (TGP) were determined by HPGPC, FT-IR, GC–MS technologies. Compared to existing methods, a more compatible method for purifying TGP was proposed. This method was faster, simpler, more effective and easier to be extended to the industrial production than the method that used in our previous work. The molecular weight of TGP was 126,513Da using HPGPC. GC–MS analysis of TGP showed that TGP was composed of seven kinds of monosaccharides, namely ribose, rhamnose, arabinose, xylose, mannose, glucose, galactose in molar ratios of 1.71:5.88:13.70:1.99:1.00:1.84:33.75. Eighteen amino acids were identified in TGP by amino acid analysis. The FT-IR spectrum of the TGP revealed also typical characteristics of polysaccharides, protein and uronic acid. [Copyright &y& Elsevier]

Abstract: A HPLC fingerprinting method based on the distribution and contents of seven major ginsenosides has been developed for the quality evaluation of Panax quinquefolium. L roots cultivated in China, Singapore and Canada. The method is ideally suited for the fingerprinting of P. quinquefolium. L samples or its derived products for sample authentication or quality control, e.g. pharmaceutical stability studies. Different extraction methods have been evaluated and a protocol established to maximize the gensinosides yields in routine operations. Hierarchical clustering analysis of the fingerprints demonstrates that the distribution and contents of ginsenosides in P. quinquefolium. L root vary depending on geographic location; and the quality of Jilin-cultivated P. quinquefolium. L roots is similar in composition to Canada-cultivated ones, which are generally considered among the best quality in P. quinquefolium. L. [Copyright &y& Elsevier]

Tunnel seismic prediction is widely used in the field of tunnel seismic advance detection. The illumination of the target and the signal‐to‐noise ratio of the data are two key factors affecting the precision of data interpretation. Current seismic prospecting has shortcomings on sites: (1) The lighting shots are solely towards one side of the tunnel wall, (2) the geophones are placed far away from the tunnel face and (3) the surface waves from the tunnel wall dominate over the reflection waves, lowering the signal‐to‐noise ratio of the data at the tunnel wall. This paper proposes a tunnel symmetrical geometry to tackle the above challenges. The arrangement is to place 12 sources uniformly on each side of the tunnel wall and six geophones on the tunnel wall and face. Results of simulated data and measured data show that the proposed method enables (1) broad illumination of the target body, (2) the enhancement of illumination energy of the target body, and (3) higher data signal‐to‐noise ratio. The proposed symmetrical geometry method provides better interpretation in terms of broader coverage, higher quality and greater distance of investigation. [ABSTRACT FROM AUTHOR]

The tunnel seismic method allows for the detection of the geology in front of a tunnel face for the safety of tunnel construction. Conventional geophones have problems such as a narrow spectral width, low sensitivity, and poor coupling with the tunnel wall. To tackle issues above, we propose a semi-automatic coupling geophone equipped with a piezoelectric sensor with a spectral range of 10–5000 Hz and a sensitivity of 2.8 V/g. After the geophone was manually pushed into the borehole, it automatically coupled with the tunnel wall under the pressure of the springs within the device. A comparative experiment showed that the data spectrum acquired by the semi-automatic coupling geophone was much higher than that of the conventional geophone equipped with the same piezoelectric sensor. The seismic data were processed in combination with forward modeling. The imaging results also show that the data acquired by the semi-automatic coupling geophone were more in line with the actual geological conditions. In addition, the semi-automatic coupling geophone's installation requires a lower amount of time and cost. In summary, the semi-automatic coupling geophone is able to efficiently acquire seismic data with high fidelity, which can provide a reference for tunnel construction safety. [ABSTRACT FROM AUTHOR]

The multi-coil sensor consisting of a series of sub-coils provides a reliable way to avoid signal distortion from excitation field. Compared with conventional coil sensors, the multi-coil sensor exhibits more complex signal conversion performance, and the conventional equivalent circuit cannot reveal the possible attenuated oscillation, which seriously degrades the detection reliability. Based on a novel equivalent circuit model, this research investigates the causes of signal oscillation and proposes and validates an effective solution, which contributes to the signal transmission characteristics of multi-coil sensors for engineering applications. [ABSTRACT FROM AUTHOR]

A large amount of oily cuttings is produced in the drilling process when the oil-based drilling fluid is used. The oil and oil-soluble additives adsorbed on the surface of the cuttings may pollute the environment. In this paper the method of silicic acid precipitation and formation of silicic acid micromicelles is used to encapsulate oil and to remove oil from the cuttings. The authors analyze the influence of the stirring time and the solution pH on the oil removal efficiency. When the pH is 2 and the stirring time is 10 min, the oil removal rate is 96%. Research into the mechanism shows the successive formation of silicic acid sol and gel in the process of silicic acid precipitation. The structure of the silicic acid micromicelles is characterized by scanning electron microscopy (SEA). The results of differential scanning calorimetry (DSC) indicate the existence of the exothermic decomposition peak of the hydrocarbons in the range from 350°C to 500°C, which proves that the micromicelle inner phase contains oil. [ABSTRACT FROM AUTHOR]

Transient electromagnetic (TEM) method is a reliable means of non‐destructive testing for fault diagnosis of grounding grid in substation. In view of the small transmitter loop of the TEM system and many measuring points and survey lines of grounding grid detection in substation. This study presents a fast solution to TEM apparent resistivity imaging for grounding grid detection using artificial neural networks. The input ‐output mapping relation of neural network is established based on TEM response characteristics of the grounding grid. The built network could map the recorded TEM data of grounding grid detection and quickly obtain the resistivity image. The proposed method offers accuracy and fast computation for the resistivity imaging of grounding grid. Feasibility and technical attractiveness of the proposed method in fast imaging of apparent resistivity is investigated with the measurement of grounding grids in the actual substations. It can be used in real time so that the recorded TEM data in substation can be calculated without re‐training, which avoids time‐consuming inversion computation. The rapid processing of massive data and submitting the detection results of the grounding grid to customers rapidly and in real time, which is expectation for a modern power industry. [ABSTRACT FROM AUTHOR]

Rapid detection of leakage passage in dykes has become a committed step in flood prevention work. The seismic surface wave method can be given the S-wave velocity information of the near-surface (≤ 20 m), and qualitatively evaluate the transverse position, depth range, and direction of the leakage passage. The low acquisition efficiency of the cone geophone in the conventional point measurement mode does not meet the requirements of rapid detection. A single survey line has a small coverage area and lacks comparison with neighboring survey lines, so it is not possible to obtain the direction of extension of the leakage passage. In this paper, we propose a rapid detection method of the towed array seismic surface wave for leakage passage of a dyke-dam. Forty-eight gravity geophones are arranged in three columns, 16 in each column, to form the array geometry. Surface wave imaging methods are inversion and fast imaging. The main shortcomings of inversion calculation are (1) lacking shallow information, (2) low vertical resolution, and (3) multiple solutions. To overcome the above issues, the imaging calculation of the surface wave dispersion curve is implemented using fast imaging method. The proposed array geometry is used to collect seismic data. The simulated data and measured data show that fast imaging has the following advantages: (1) It can make full use of the dispersion curve of broadband seismic data, does not lose shallow information, and has high imaging accuracy. (2) It uses the dispersion curve directly for imaging, does not lose any details of velocity changes, and has a high vertical resolution. (3) The imaging results are unique. In contrast to the inversion results, the fast imaging results clearly distinguish the location of the leakage passage and highlight the lateral variability of the leakage passage. The results of the model data and measured data demonstrate the efficiency and high resolution of the towed array seismic geometry and the fast imaging method for leakage passage detection. • The array geometries can clearly display the lateral variation of the low-velocity area. • The array geometries can indicate the direction of the leakage passage. • The fast imaging method can make full use of the dispersion curves of high frequency and low frequency. • The fast imaging method can obtain unique imaging results and avoid multiple solutions. [ABSTRACT FROM AUTHOR]

A bipolar pulse current source is proposed for a highly inductive load. The current source exploits a noninductive capacitor to store or release the energy back to and from inductive load during switching on or off of power inverter. A boost module is designed at the dc side of inverter to supplement the required energy gap so that edge steepness of the load current can be improved. The capacitor and boost elements are configured based on the analysis of capacitor impact on the load current and boost inductor current. The stability of load current can be guaranteed by the multiple driving pulses generated from closed-loop control of boost switch, regardless of load changes or initial pulse width offset. An experiment prototype is built to generate a flat-top 20 A current with the 200 μs rise/fall time for an inductive load of 2 mH or higher. Due to the steep rising and falling edges, the inductive load can realize high-frequency pulse currents. Moreover, the steep pulse current source can excite strong magnetic field, which make it especially useful for the inductive coils of high-power geophysical transient electromagnetic method (TEM) transmitter. [ABSTRACT FROM AUTHOR]

The rapid detection of urban road disasters has become an urgent problem. The continuous towed geophysical method is an important method for rapid general detection. Ground-penetrating radar and transient electromagnetic have realized continuous towed detection, but the seismic method cannot do it. The reflection seismic method has the advantages of deep detection depth and high resolution. To adapt to the rapid deployment of geophones on urban hardened pavement, a gravity geophone was designed to realize towed acquisition. However, the data acquisition is far from meeting the needs of large area rapid detection on urban roads. In this paper, a continuous towed seismic data collection method is proposed for the first time, that is, the vibration generated by the friction between the geophone base and the ground is used as the seismic source to realize the rapid data acquisition on the urban roads. When the vehicle-mounted seismic equipment is used and the required lateral resolution is 0.5 m, the continuous towed seismic data acquisition efficiency is about 5 km/h. Continuous towed seismic data has a low-resolution and low signal-to-noise ratio, and the real weak reflected signal is drowned by strong energy noise. To solve these problems, this paper proposes a correlation stack method to extract the stack section. When seismic data is collected with the continuous towed seismic equipment, the seismic source signal is not the approximate sharp plus signal, so the resolution of the extracted stack section is still low. Single detection results are difficult to distinguish near-surface structures. The continuous towed seismic acquisition method has a low cost and can realize the rapid repeated detection of the same survey line. The model data and measured data prove that the proposed data acquisition scheme and data processing method have the following advantages: 1) The continuous towed seismic acquisition method can improve the data acquisition efficiency, reduce the cost of data acquisition, and is suitable for large area rapid detection. 2) The correlation stack method can extract reflected signals with real weak energy. 3) Stack processing for multiple detection data can improve the resolution and enhance the energy of real weak signals. The continuous towed seismic data acquisition and the data processing method can realize the rapid inspection and detection of urban roads and has practical engineering application value. • The continuous towed seismic acquisition method can improve the data acquisition efficiency. • The correlation stack method can extract reflected signals with real weak energy. • Stack processing for multiple detection data can enhance the energy of weak signals. • The proposed method is the most efficient and environmentally friendly. [ABSTRACT FROM AUTHOR]

The pulsed eddy current (PEC) inspection is considered a versatile non-destructive evaluation technique, and it is widely used in metal thickness quantifications for structural health monitoring and target recognition. However, for non-ferromagnetic conductors covered with non-uniform thick insulating layers, there are still deficiencies in the current schemes. The main purpose of this study is to find an effective feature, to measure wall thinning under the large lift-off variations, and further expand application of the PEC technology. Therefore, a novel method named the dynamic apparent time constant (D-ATC) is proposed based on the coil-coupling model. It associates the dynamic behavior of the induced eddy current with the geometric dimensions of the non-ferromagnetic metallic component by the time and amplitude features of the D-ATC curve. Numeral calculations and experiments show that the time signature is immune to large lift-off variations. [ABSTRACT FROM AUTHOR]

Abstract: Two isomeric phenylethanoid glycosides, acteoside and isoacteoside were isolated and purified from the seeds of Plantago psyllium L. for the first time by high-speed counter-current chromatography (HSCCC) using a solvent system consisting of ethyl acetate–water (1:1, v:v). By injecting 200mg of the n-butanol extract of P. psyllium for five consecutive times, the two-step HSCCC procedure yielded a total of 165mg of acteoside and 17.5mg of isoacteoside from 978mg extract. The recovery rates for acteoside and isoacteoside were 90 and 84%, respectively, and the purities were 98 and 94%, respectively. The HSCCC fractions were analyzed by HPLC and the structures were identified by UV, LC–APCI–MS in negative ion mode, and confirmed by NMR experiments. [Copyright &y& Elsevier]

At present, there are no appropriate exploration methods for the shallow water geophysical surveys with depths less than 100 m. In this paper, the detection feasibility of small-loop transient electromagnetic method (TEM) in shallow water was researched from both theoretical and practical application aspects. Firstly, the propagation characteristics of the multi-turn small-loop electromagnetic field and the magnetic dipole in space were compared. Next, a homogeneous half-space shallow water model and a typical low-resistance abnormal body shallow water model were established by using the finite-difference time-domain (FDTD) method. The research results indicate that the strength of the magnetic field intensity is mainly affected by the depth of water, resistivity, and emission current. The response curve of the low-resistance abnormal body at different times indicates double-peak attenuation law. The response of low-resistance abnormal at different depths of shallow water indicates single-peak, double-peak, and peak-to-valley attenuation laws, and the response of low-resistance abnormal at different resistivity of shallow water indicates single-peak and peak-to-valley attenuation laws. The EA parameters were introduced to analyze the effects of different thicknesses and different resistivity on the response of low-resistance abnormal. Finally, the effectiveness and accuracy of the method were verified when comparing the high-density resistivity method with the results of the transient electromagnetic method on water. The research work provides a theoretical reference for the qualitative analysis of the response characteristics and data processing interpretation of the small-loop transient electromagnetic method in shallow water. • A small-loop TEM method suitable for shallow water exploration is proposed. • The EA parameters were redefined. • The detection results of the small-loop TEM in shallow water were verified. [ABSTRACT FROM AUTHOR]

Seismic imaging is the most effective geophysical method and has been extensively implemented to detect potential geological hazards in tunnels during construction. The coupling of geophones and the design of geometry in tunnels are the two major challenges. To ensure successful coupling, a high-sensitivity semi-automatic coupling geophone with a broadband was designed. In practice, this geophone is attached with a wheel and two springs. Once inserted into the borehole, an automatic coupling action occurs. This semi-automatic coupling design within the geophone not only guarantees good coupling, but reduces the time and costs usually required to install a traditional geophone. In the use of geophones for tunnel seismic detection, we propose two new two-dimensional (2D) seismic geometries based on the two commonly used geometries. A test to assess the effectiveness of the qualities of imaging from four geometries was completed by comparing the results of the forward modeling of sandwich models. The conclusion is that the larger the horizontal offset of the layout geometry, the higher the resolution of the imaging; the larger the vertical offset, the weaker the mirror image. The vertical offset is limited due to the narrow tunnel condition. Therefore, the mirror effect cannot be entirely eliminated; however, it can be further suppressed by constructing 2D geometry. The two newly proposed 2D geometries caused the imaging arc of the inter-layer, but suppressed the mirror image. The mirror image added a significant number of errors to the data, which could misguide tunnel construction; therefore the new 2D geometries are more reasonable than the two most commonly used. We applied one of the two new 2D geometries that was more practical to an actual project, the Chongqing Jinyunshan Tunnel in China, and acquired high-quality seismic data using two semi-automatic coupling geophones. The detection results were essentially consistent with the excavation conclusions. [ABSTRACT FROM AUTHOR]

Objective: To report the successful conservative management of two patients with acute adnexal torsion by ultrasound-guided transvaginal ovarian cystic aspiration. Design: Case report. Setting: A reproductive medical center. Patients: Two women with OHSS who had acute lower abdominal pain, nausea, and vomiting, and were found to have acute adnexal torsion. Intervention(s): An ultrasound-guided transvaginal ovarian cystic aspiration was performed promptly. Main Outcome Measure(s): The clinical symptoms of acute adnexal torsion after the procedure. Result(s): After the cystic aspiration, acute lower abdominal pain, nausea, and vomiting were relieved immediately. The postoperative course was normal. Neither of the patients had clinical signs of pelvic or systemic thromboembolism. Conclusion(s): Ultrasound-guided transvaginal ovarian cystic aspiration is a simple, safe, and effective method for the conservative management of adnexal torsion. [Copyright &y& Elsevier]