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Reliability testing and failure modelling is crucial and very challenging for modern electronics, especially safety critical electronics-based systems working under harsh environmental conditions. In this paper, an approach based on ultrasonic Non-Destructive Evaluation (NDE) is proposed to establish a failure model for solder joints which is urgently needed for prognostic and health management of electronics. Printed Circuit Boards (PCB) containing flip-chip and Area Array packages were designed and aged using Accelerated Thermal Cycling (ATC) testing. During ATC testing solder joint degradation was regularly monitored by taking out the test boards from the temperature chamber at four thermal cycle intervals for ultrasonic micro-imaging. Data pre-processing techniques including dynamic range-based intensity normalization, gain compensation, and calibration for random transducer defocusing errors were developed to enhance the data consistency, integrity and accuracy. Furthermore, solder joint image labelling and segmentation methods were developed by exploiting the geometrical features of the solder joints to extract individual solder joints and Region of Interests (ROIs) from the sequential ultrasound images collected throughout the testing. The mean intensity of the ROIs was used as the precursor to degradation to build the solder joint failure model, from which cycles to failure for individual solder joints are finally derived for life prediction. [ABSTRACT FROM AUTHOR]

High- T c superconductivity with possible T c ≈ 80 K has been reported in the single crystal of La3Ni2O7 under high pressure. Based on the electronic structure given by the density functional theory calculations, we propose an effective bi-layer model Hamiltonian including both 3 d z 2 and 3 d x 2– y 2 orbital electrons of the nickel cations. The main feature of the model is that the 3 d z 2 electrons form inter-layer σ -bonding and anti-bonding bands via the apical oxygen anions between the two layers, while the 3 d x 2– y 2 electrons hybridize with the 3 d z 2 electrons within each NiO2 plane. The chemical potential difference of these two orbital electrons ensures that the 3 d z 2 orbitals are close to half-filling and the 3 d x 2– y 2 orbitals are near quarter-filling. The strong on-site Hubbard repulsion of the 3 d z 2 orbital electrons gives rise to an effective inter-layer antiferromagnetic spin super-exchange J. Applying pressure can self dope holes on the 3 d z 2 orbitals with the same amount of electrons doped on the 3 d x 2– y 2 orbitals. By performing numerical density-matrix renormalization group calculations on a minimum setup and focusing on the limit of large J and small doping of 3 d z 2 orbitals, we find the superconducting instability on both the 3 d z 2 and 3 d x 2– y 2 orbitals by calculating the equal-time spin singlet pair–pair correlation function. Our numerical results may provide useful insights in the high- T c superconductivity in single crystal La3Ni2O7 under high pressure. [ABSTRACT FROM AUTHOR]

In ultrasonic array imaging, 3D ultrasonic wavefields are normally recorded by an ultrasonic piezo array transducer. Its performance is limited by the configuration and size of the array transducer. In this paper, a method based on digital holographic interferometry is proposed to record the 3D ultrasonic wavefields instead of the array transducer, and the measurement system consisting of a pulsed laser, ultrasonic excitation, and synchronization and control circuit is designed. A consecutive sequence of holograms of ultrasonic wavefields are recorded by the system. The interferograms are calculated from the recorded holograms at different time sequence. The amplitudes and phases of the transient ultrasonic wavefields are recovered from the interferograms by phase unwrapping. The consecutive sequence of transient ultrasonic wavefields are stacked together to generate 3D ultrasonic wavefields. Simulation and experiments are carried out to verify the proposed technique, and preliminary results are presented. [ABSTRACT FROM AUTHOR]

The miniaturization and three dimensional die stacking in advanced microelectronic packages poses a big challenge to their non-destructive evaluation by acoustic microimaging. In particular, their complicated structures and multiple interfaces make the interpretation of acoustic data even more difficult. A common phenomenon observed in acoustic microimaging of microelectronic packages is the edge effect phenomena, which obscures the detection of defects such as cracks and voids. In this paper, two dimensional finite element modelling is firstly carried out to numerically simulate acoustic microimaging of modern microelectronic packages. A flip-chip with a 140 µm solder bump and a 230 MHz virtual transducer with a spot size of 16 µm are modelled. Crack propagation in the solder bump is further modelled, and B-scan images for different sizes of micro-cracks are obtained. C-line plots are then derived from the simulated B-scan images to quantitatively analyze the edge effect. Gradual progression of the crack is found to have a predictable influence on the edge effect profile. By exploiting this feature, a crack propagation characterization method is developed. Finally, an experiment based on the accelerated thermal cycling test is designed to verify the proposed method. [ABSTRACT FROM AUTHOR]

Edge effect is a common phenomenon observed in acoustic micro-imaging of microelectronic packages. In this paper, using flip chip package geometry as a test vehicle, finite element modelling is carried out to study the fundamental mechanism of the edge effect phenomenon. C-Line plot technique is developed for the characterization of edge effects in acoustic C-scan images, in particular solder joint C-scan images. Simulated results are compared to experimental results. Results reveal that edge effect generation is mainly attributed to the under-bump-metallisation structure. In addition, through analysis of the C-Line profile of edge effects, the impact of the transducer focal point and the spot size on the edge effect is investigated. Results show that slight off-focus can reduce the severity of the edge effect in which image sharpness is a trade-off. [ABSTRACT FROM AUTHOR]

Abstract: One of the difficulties in light pen 3D vision measurement is the stereo matching of the light-spot image points. Therefore, the SoftPoist algorithm is adopted to determine the corresponding relations of the light-spot image point in the left and right images to the spatial light spots through double-layer circulation iterative optimization, and then solve the stereo matching problem. The SoftPoist algorithm improves the POSIT algorithm so that the improved algorithm can be applied to huge amounts of light-spot feature points where the corresponding relations of the image points to its object unknown. The iterative optimization of the matching and pose estimation parameters can be computed if only there are four noncoplanar feature points, so the applied scope of the improved algorithm is much wider. The experiment results show that the algorithm can keep the measurement accuracy and shorten the time of the program operation to enhance matching efficiency and the improved algorithm has the practical value. [Copyright &y& Elsevier]

In order to improve the survival ability of armored vehicles in the war, the protecting technology has been attached importance and developed completely by the world military powers. The paper presented the research state and protecting level of modern armor, and enumerated protecting furnishment of advanced armored vehicles, and summarized the research state and level of key protecting technology-armor material. After introducing situation of armor protecting technology, taking the research content of U. S. and U. K., the development trend to the modern armor technology-synthesis protection system were analyzed. [ABSTRACT FROM AUTHOR]

Abstract: Many sparse signal representation (SSR) algorithms have been developed in the past decade. The advantages of SSR such as compact representations and super resolution lead to the state of the art performance of SSR for processing ultrasonic non-destructive evaluation (NDE) signals. Choosing a suitable SSR algorithm and designing an appropriate overcomplete dictionary is a key for success. After a brief review of sparse signal representation methods and the design of overcomplete dictionaries, this paper addresses the recent accomplishments of SSR for processing ultrasonic NDE signals. The advantages and limitations of SSR algorithms and various overcomplete dictionaries widely-used in ultrasonic NDE applications are explored in depth. Their performance improvement compared to conventional signal processing methods in many applications such as ultrasonic flaw detection and noise suppression, echo separation and echo estimation, and ultrasonic imaging is investigated. The challenging issues met in practical ultrasonic NDE applications for example the design of a good dictionary are discussed. Representative experimental results are presented for demonstration. [Copyright &y& Elsevier]

Various signal processing techniques have been used for the enhancement of defect detection and defect characterisation. Cross-correlation, filtering, autoregressive analysis, deconvolution, neural network, wavelet transform and sparse signal representations have all been applied in attempts to analyse ultrasonic signals. In ultrasonic nondestructive evaluation (NDE) applications, a large number of materials have multilayered structures. NDE of multilayered structures leads to some specific problems, such as penetration, echo overlap, high attenuation and low signal-to-noise ratio. The signals recorded from a multilayered structure are a class of very special signals comprised of limited echoes. Such signals can be assumed to have a sparse representation in a proper signal dictionary. Recently, a number of digital signal processing techniques have been developed by exploiting the sparse constraint. This paper presents a review of research to date, showing the up-to-date developments of signal processing techniques made in ultrasonic NDE. A few typical ultrasonic signal processing techniques used for NDE of multilayered structures are elaborated. The practical applications and limitations of different signal processing methods in ultrasonic NDE of multilayered structures are analysed. [ABSTRACT FROM PUBLISHER]

Objective: To investigate the effect of treatment of osteoporotic proximal humeral fractures in elderly patients with a proximal humeral internal locking system (PHILOS) and minimally invasive injectable graft (MIIG). Methods: Patients who conformed to the inclusion criteria were randomly divided into two groups: group A (21 cases) were treated with PHILOS alone and group B (29 cases) were treated with PHILOS augmentation plus minimally invasive injectable graft (MIIG) X3 Hivisc. Postoperative follow-up was performed regularly to check for complications, reduction loss and fracture healing by imaging. Shoulder joint function was scored and clinical results evaluated according to the Neer scoring system. Results: All patients were followed-up and achieved fracture healing. The complication rate in group A (six cases) was greater than in group B (one case), the differences being statistically significant. The reduction loss in group A (2.9 ± 0.4 mm) was greater than in group B (1.5 ± 0.3 mm), this difference also being statistically significant. According to the Neer system, the excellent and good rate was 76.2% in group A and 82.8% in group B. Conclusion: PHILOS using MIPPO and augmented with MIIG X3 Hivisc produces satisfactory clinical results in aged patients with osteoporotic proximal humeral fractures and the method has advantages such as relatively minor trauma, stable fixation, fewer complications, and better joint function. [ABSTRACT FROM AUTHOR]

Abstract: We show that there is a topological (Berry phase) term in the non-linear σ model description of the spin chain. It distinguishes the linear and projective representations of the symmetry group, in exact analogy to the well-known θ-term of the spin chain. The presence of the topological term is due to the fact that . We discuss the implication of our results on the spectra of the spin chain, and connect it with a recent solvable spin model which exhibits valence bond solid ground state and edge degeneracy. [Copyright &y& Elsevier]

Sparse signal representations from overcomplete dictionaries are the most recent technique in the signal processing community. Applications of this technique extend into many fields. In this paper, this technique is utilized to cope with ultrasonic flaw detection and noise suppression problem. In particular, a noisy ultrasonic signal is decomposed into sparse representations using a sparse Bayesian learning algorithm and an overcomplete dictionary customized from a Gabor dictionary by incorporating some a priori information of the transducer used. Nonlinear postprocessing including thresholding and pruning is then applied to the decomposed coefficients to reduce the noise contribution and extract the flaw information. Because of the high compact essence of sparse representations, flaw echoes are packed into a few significant coefficients, and noise energy is likely scattered all over the dictionary atoms, generating insignificant coefficients. This property greatly increases the efficiency of the pruning and thresholding operations and is extremely useful for detecting flaw echoes embedded in background noise. The performance of the proposed approach is verified experimentally and compared with the wavelet transform signal processor. Experimental results to detect ultrasonic flaw echoes contaminated by white Gaussian additive noise or correlated noise are presented in the paper. [ABSTRACT FROM AUTHOR]

Abstract: In a highly competitive market, reliable techniques for manufacturing quality control of electronic devices are demanded. Characterisation of modern microelectronic package integrity becomes more difficult due to the continued miniaturisation of electronic device and the complexity of advanced micro-assembling technologies such as chip-scale packages and 3D IC stacks. In this paper, sparse representations of acoustic signals are sought to improve the scanning acoustic microscopy (SAM), a common non-destructive tool for failure analysis of microelectronic packages. Sparse representation of an ultrasonic signal is obtained by decomposing it in an overcomplete dictionary. Detection and location of ultrasonic echoes are then performed on the basis of the resulting redundant representation. The method offers a solution to the deconvolution problem for restoration of the ultrasonic reflectivity function. It can restore closely space overlapping echoes beyond the resolution of the conventional SAM system. It also produces high resolution and accurate estimates for ultrasonic echo parameters, i.e., time-of-flight, amplitude, centre frequency, and bandwidth. These merits of the proposed method are explored in various potential applications for microelectronic package characterisation. [Copyright &y& Elsevier]

In this article, a novel distributed circuit model of coplanar waveguide to microstrip (CPW-M) transition is presented by using generalized telegrapher equation. In comparison with conventional nonuniform transmission line equation, the generalized telegrapher equation has two additional terms, dependent series voltage and shunt current sources, which represent local radiation effect from discontinuities of the nonuniform transmission line itself. Based on the full-wave numerical results, the distributed circuit parameters can be extracted by using the generalized telegrapher equation. Since the generalized telegrapher equation coefficients are determined by dynamic numerical methods and the coefficients are invariant with the line excitation and load, the equation is dynamical rather TEM. The numerical experiments show that the novel distributed circuit model for this CPW-M transition can have broadband characteristics. As a preparatory experiment, an improved CAD method using this model is utilized to model different structures of CPW-M transition. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1323–1328, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22461 [ABSTRACT FROM AUTHOR]

Abstract: Recently, adaptive sparse representations of ultrasonic signals have been utilized to improve the performance of scanning acoustic microscopy (SAM), a common nondestructive tool for failure analysis of microelectronic packages. The adaptive sparse representation of an ultrasonic signal is generated by decomposing it in a learned overcomplete dictionary using a sparse basis selection algorithm. Detection and location of ultrasonic echoes are then performed on the basis of the resulting redundant representation. This paper investigates the effect of sparse basis selection algorithms on ultrasonic signal representation. The overcomplete independent component analysis, focal underdetermined system solver (FOCUSS), and sparse Bayesian learning algorithms are examined. Numerical simulations are performed to quantitatively analyze the efficiency of ultrasonic signal representations. Experiments with ultrasonic A-scans acquired from flip-chip packages are also carried out in the study. The efficiency of ultrasonic signal representations are evaluated in terms of the different criteria that can be used to measure its performance for different SAM applications, such as waveform estimation, echo detection, echo location and C-scan imaging. The results show that the FOCUSS algorithm performs best overall. [Copyright &y& Elsevier]

Abstract: Acoustic microimaging (AMI) is used as an important non-destructive tool in semiconductor reliability evaluation and failure analysis. As advanced microelectronic packages are being produced smaller and thinner, detection of the internal features and defects in the packages is approaching the resolution limits for conventional AMI. To meet this challenge, an acoustic time–frequency domain imaging technique is proposed in this paper, which utilizes the excellent time–frequency localization characteristics of the continuous wavelet transform (CWT) to improve the axial resolution of AMI, without increasing acoustic frequencies. The proposed technique is compared to time domain AMI, frequency domain AMI and sparse signal representation based AMI (SSRAMI) with respect to both axial resolution and robustness. Simulation results show that the proposed technique has superior performance compared to time domain and frequency domain AMI techniques, and has close performance to SSRAMI but with less computation load. [Copyright &y& Elsevier]

In this paper, two categories of transform coding and subband coding are comparatively studied for compressing ultrasonic NDE images. The data compression performance of the discrete cosine transform-, the Karhunen-Loève transform-, and the discrete wavelet transform-based codecs are examined by being applied to ultrasonic NDE images. The effects of these compression methods on the analysis of ultrasonic information in compressed ultrasonic images are examined. Moreover, evaluation of the main elements in image coding system is performed to explore the important factors, which are worth paying more attention when developing a special image compression technique for ultrasonic NDE images. [Copyright &y& Elsevier]

Holographic-like three-dimensional (3D) acoustic imaging is developed for micro-nondestructive evaluation of microelectronics. It is implemented by stacking all the interface slices together to locate and identify hidden defects. Matching pursuit based acoustic time-frequency domain imaging is proposed to overcome the wavelength limit of axial resolution so that ultra-thin slices are generated. Experiments are performed on 3D acoustic data collected from microelectronic packages. Results show that the proposed technique resolves closely spaced features that are unavailable by conventional acoustic imaging, revealing more image details of defects. [ABSTRACT FROM AUTHOR]

The recent discovery of superconductivity in infinite-layer nickelates generates tremendous research endeavors, but the ground state of their parent compounds is still under debate. Here, we report experimental evidence for the dominant role of Kondo scattering in the underdoped Nd1−xSrxNiO2 thin films. A resistivity minimum associated with logarithmic temperature dependence in both longitudinal and Hall resistivities are observed in the underdoped Nd1−xSrxNiO2 samples before the superconducting transition. At lower temperatures down to 0.04 K, the resistivities become saturated, following the prediction of the Kondo model. A linear scaling behavior |$\sigma _{{\boldsymbol{xy}}}^{{{\bf AHE}}}{\rm{\ }}\sim{\rm{\ }}{\sigma }_{{\boldsymbol{xx}}}$| between anomalous Hall conductivity |$\sigma _{{\boldsymbol{xy}}}^{{\bf{AHE}}}$| and conductivity |${\sigma }_{{\boldsymbol{xx}}}{\rm{\ }}$| is revealed, verifying the dominant Kondo scattering at low temperature. The effect of weak (anti-)localization is found to be secondary. Our experiments can help in clarifying the basic physics in the underdoped Nd1−xSrxNiO2 infinite-layer thin films. [ABSTRACT FROM AUTHOR]

Objective: To determine the value of Böhler's angle (BA) in a group of Chinese people, analyze possible factors that influence it, and compare BA with that in previous literature. Methods: A total of 143 cases, aged from 4 to 79 years, were enrolled in the study, including 64 males and 79 females (79 left feet and 64 right feet). Radiographs were independently measured by six observers. Age, sex, body side, subtalar joint congruity (STJC), and X‐beam obliquity (TT) were recorded. The database was assessed based on intraobserver agreement, data distribution, the randomness of case selection, and the ratio equality of binomial variables. Then, the normal value of BA was established, as well as the correlation between BA and other parameters. Results: In the present study, the interobserver reliability of BA, STJC, and TT was excellent. The BA data revealed a normal distribution, and the randomness of case selection was verified for age, sex, and body side. The ratio of sex and body side was equal. Homogeneity of variance was observed when comparing the value of BA between different groups. The value of BA was 31.6° ± 5.19° (range, 20.08°–47.19°), which was not related to age, sex, body side, and minor X‐ray beam obliquity. BA application was not suitable for individuals younger than 10 years. The mean value of BA in this study was not identical with those in previous reports. This demonstrated that BA varies for different races. Conclusion: For Chinese people, 30° to 33° is recommended as the target value of BA for calcaneal fracture reduction, except in children under 10 years of age. [ABSTRACT FROM AUTHOR]

Post‐stroke depression, a common complication after stroke, severely affects the recovery and quality of life of patients with stroke. Owing to its complex mechanisms, post‐stroke depression treatment remains highly challenging. Hippocampal synaptic plasticity is one of the key factors leading to post‐stroke depression; however, the precise molecular mechanisms remain unclear. Numerous studies have found that neurotrophic factors, protein kinases and neurotransmitters influence depressive behaviour by modulating hippocampal synaptic plasticity. This review further elaborates on the role of hippocampal synaptic plasticity in post‐stroke depression by summarizing recent research and analysing possible molecular mechanisms. Evidence for the correlation between hippocampal mechanisms and post‐stroke depression helps to better understand the pathological process of post‐stroke depression and improve its treatment. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Recent experiment has shown that the ABC-stacked trilayer graphene-boron nitride Moire super-lattice at half-filling is a Mott insulator. Based on symmetry analysis and effective band structure calculation, we propose a valley-contrasting chiral tight-binding model with local Coulomb interaction to describe this Moire super-lattice system. By matching the positions of van Hove points in the low-energy effective bands, the valley-contrasting staggered flux per triangle is determined around π / 2. When the valence band is half-filled, the Fermi surfaces are found to be perfectly nested between the two valleys. Such an effect can induce an inter-valley spiral order with a gap in the charge excitations, indicating that the Mott insulating behavior observed in the trilayer graphene-boron nitride Moire super-lattice results predominantly from the inter-valley scattering. [ABSTRACT FROM AUTHOR]

Defect classification is an important issue in ultrasonic non-destructive evaluation. A layered multi-class support vector machine (LMSVM) classification system, which combines multiple SVM classifiers through a layered architecture, is proposed in this paper. The proposed LMSVM classification system is applied to the classification of welding defects from ultrasonic test signals. The measured ultrasonic defect echo signals are first decomposed into wavelet coefficients by the wavelet packet transform. The energy of the wavelet coefficients at different frequency channels are used to construct the feature vectors. The bees algorithm (BA) is then used for feature selection and SVM parameter optimisation for the LMSVM classification system. The BA-based feature selection optimises the energy feature vectors. The optimised feature vectors are input to the LMSVM classification system for training and testing. Experimental results of classifying welding defects demonstrate that the proposed technique is highly robust, precise and reliable for ultrasonic defect classification. [ABSTRACT FROM AUTHOR]

• Recent advances in high-pressure membrane fouling during wastewater reuse were reported. • Combined fouling behaviors and mechanisms caused by secondary effluent were reviewed. • Coexisting foulants' effects on pretreatment mitigation performances were emphasized. • Knowledge gaps were identified and future research directions were proposed. High-pressure membrane technology has demonstrated remarkable efficacy in municipal wastewater reuse. However, membrane fouling remains a bottleneck hampering its development and widespread implementation. Given the coexistence of various organic, inorganic, and biological foulants in wastewater, their individual and combined fouling behaviors are complicated and could influence the fouling mitigation performance of pretreatment strategies. Herein, we provided a comprehensive review of the combined fouling behaviors on high-pressure membranes and the fouling mitigation performances of various pretreatment strategies. Initially, the membrane fouling behaviors and mechanisms of single types of foulants and their combination were discussed in-depth, along with a detailed examination of the complex fouling resulting from actual secondary effluent. Subsequently, the impact of the conventional pretreatment techniques on high-pressure membrane fouling was carefully evaluated, from both the positive and negative aspects. The influence of the coexistence and interaction of various types of foulants was particularly emphasized. Finally, the challenges that high-pressure membrane processes still confront and the future research directions in this field were highlighted. [ABSTRACT FROM AUTHOR]

Abstract: Acoustic Micro Imaging (AMI) techniques have been widely used as a non destructive evaluation (NDE) tool in evaluating both microelectronic packages and solder joints. However, there are a lack of analysis tools and automated inspection techniques to facilitate the inspection process. This paper presents a novel approach to extract the solder joint’s features from ultrasound images for automated solder joint assessment. The proposed method consists of three stages: solder joint detection, feature extraction, and defect evaluation. Firstly, a gradient based circular Hough transform is employed to detect the solder joints in acquired ultrasound images. Subsequently, feature extraction is carried out by a radial gradient based region growing algorithm. Finally, defect evaluation is achieved by analysing the variation of the image features automatically. Cross-sectional analysis was performed to validate and evaluate the performance of the solder joint inspection system. The results show that image features obtained by the system can be used easily to distinguish between a healthy and fractured joint, thus confirming the feasibility of the automated AMI inspection technique. [Copyright &y& Elsevier]

Abstract: High-speed counter-current chromatography (HSCCC) is applied to the purification of coenzyme Q10 (CoQ10) for the first time. CoQ10 was obtained from a fermentation broth extract. A non-aqueous two-phase solvent system composed of heptane–acetonitrile–dichloromethane (12:7:3.5, v/v/v) was selected by analytical HSCCC and used for purification of CoQ10 from 500mg of the crude extract. The separation yielded 130mg of CoQ10 at an HPLC purity of over 99%. The overall results of the present studies show the advantages of HSCCC over an alternative of silica gel chromatography followed by recrystallization. These advantages extend to higher purity (97.8% versus 93.3%), recovery (88% versus 74.3%) and yield (26.4% versus 23.4%). An effort to avoid the toxic, expensive solvent CH2Cl2 was unsuccessful, but at least its percentage is low in the solvent system. [Copyright &y& Elsevier]

The conventional calibration methods based on a perspective camera model are not suitable for the underground camera with two-layer glasses, which is specially designed for explosion proof and dust removal in a coal mine. Underground camera modeling and calibration algorithms are urgently needed to improve the precision and reliability of underground visual measurement systems. This article presents a novel geometrically driven underground camera calibration algorithm for a boom-type roadheader. The underground camera model is established under coplanarity constraints, considering explicitly the impact of refraction triggered by the two-layer glasses and deriving the geometrical relationship of equivalent collinearity equations. On this basis, we perform parameters calibration based on a geometrically driven calibration model, which are 2D–2D correspondences between the image points and object coordinates of the planar target. A hybrid Levenberg–Marqurdt (LM) and particle swarm optimization (PSO) algorithm is further proposed in terms of the dynamic combination of the LM and PSO, which optimizes the underground camera calibration results by minimizing the error of the nonlinear underground camera model. The experimental results demonstrate that the pose errors caused by the two-layer glass refraction are well corrected by the proposed method. The accuracy of the cutting-head pose estimation has increased by 55.73%, meeting the requirements of underground excavations. [ABSTRACT FROM AUTHOR]

As two emerging pollutants of great concern, microplastics (MPs) and antibiotics inevitably cooccur in various aquatic environments and interact with each other, impacting the fate and ecological risks. Aging obviously complicates their interaction and deserves further study. Therefore, the adsorption-desorption behaviors of ciprofloxacin (CIP) onto polystyrene (PS) fragments with various aging extent were investigated, and the key physiochemical properties influencing the interaction and the interaction mechanisms were clarified by redundancy analysis, FTIR and XPS spectra. The physicochemical properties of PS MPs were significantly changed with aging time, and the morphological and chemical changes seemed to occur asynchronously. The adsorption of CIP onto the pristine PS MPs relied on physisorption, especially the ion-involving electrostatic and cation-π interaction. Due to the hydrogen bonding formed by the C–OH, C O, and O–C O groups of PS and CIP, the adsorption capacities of the aged PS MPs were greatly increased. The desorption efficiency of CIP from MPs in the gastric fluid was closely related to the solution ionic strengths, C–OH and C O groups of MPs, while that in the intestinal fluid was associated with O–C O groups of MPs. The different impact factors could be well described by the differences in the chemical components and pHs of the simulated gastric and intestinal fluids. This study gives a comprehensive understanding of the adsorption-desorption behaviors of antibiotics onto MPs at a molecular level and indicates that MPs could act as Trojan horses to transport antibiotics into aquatic organisms. [Display omitted] • Redundancy analysis identified MPs' key properties affecting adsorption/desorption. • Hydrogen bonding, electrostatic and cation-π interaction were crucial for CIP adsorption. • The C–OH, C O, and O–C O groups of aged MPs were involved in the hydrogen bonding with CIP. • Desorption of CIP in the gastric fluid relied on the C–OH and C O groups of MPs. • Desorption of CIP in the intestinal fluid was related to the O–C O groups of MPs. [ABSTRACT FROM AUTHOR]

Negative signs in many-body wavefunctions play an important role in quantum mechanics because interference relies on cancellation between amplitudes of opposite signs. The ground-state wavefunction of double semion model contains negative signs that cannot be removed by any local transformation. Here we study the quantum effects of these intrinsic negative signs. By proposing a generic double semion wavefunction in tensor network representation, we show that its norm can be mapped to the partition function of a triangular lattice Ashkin-Teller model with imaginary interactions. We use numerical tensor-network methods to solve this non-Hermitian model with parity-time symmetry and determine a global phase diagram. In particular, we find a dense loop phase described by non-unitary conformal field theory and a parity-time-symmetry breaking phase characterized by the zeros of the partition function. Therefore, our work establishes a connection between the intrinsic signs in the topological wavefunction and non-unitary phases in the parity-time-symmetric non-Hermitian statistical model. While negative signs in wave functions are known to play a relevant role in many-body quantum mechanics, their physical consequences on the nature of topologically ordered phases of matter is still unclear. Here, the authors use tensor network methods to show that the intrinsic negative signs of the double semion model are responsible for the non-unitary phases and non-unitary phase transitions found in the phase diagram. [ABSTRACT FROM AUTHOR]

The Mott transition is one of the fundamental issues in condensed matter physics, especially in the system with antiferromagnetic long-range order. However, such a transition is rare in quantum spin liquid (QSL) systems without long-range order. Here we report the experimental pressure-induced insulator to metal transition followed by the emergence of superconductivity in the QSL candidate NaYbSe2 with a triangular lattice of 4f Yb3+ ions. Detail analysis of transport properties in metallic state shows an evolution from non-Fermi liquid to Fermi liquid behavior when approaching the vicinity of superconductivity. An irreversible structure phase transition occurs around 11 GPa, which is revealed by the x-ray diffraction. These results shed light on the Mott transition in the QSL systems. [ABSTRACT FROM AUTHOR]

Unfortunately, the panels of (f) in Figures 1, 2, and 4. [ABSTRACT FROM AUTHOR]

Increasing availability of reactive nitrogen (N) threatens plant diversity in diverse ecosystems. While there is mounting evidence for the negative impacts of N deposition on one component of diversity, species richness, we know little about its effects on another one, species evenness. It is suspected that ecosystem management practice that removes nitrogen from the ecosystem, such as hay-harvesting by mowing in grasslands, would mitigate the negative impacts of N deposition on plant diversity. However, empirical evidence is scarce. Here, we reported the main and interactive effects of N deposition and mowing on plant diversity in a temperate meadow steppe with 4-year data from a field experiment within which multi-level N addition rates and multiple N compounds are considered. Across all the types of N compounds, species richness and evenness significantly decreased with the increases of N addition rate, which was mainly caused by the growth of a tall rhizomatous grass, Leymus chinensis. Such negative impacts of N addition were accumulating with time. Mowing significantly reduced the dominance of L. chinensis, and mitigated the negative impacts of N deposition on species evenness. We present robust evidence that N deposition threatened biodiversity by reducing both species richness and evenness, a process which could be alleviated by mowing. Our results highlight the changes of species evenness in driving the negative impacts of N deposition on plant diversity and the role of mowing in mediating such negative impacts of N deposition. [ABSTRACT FROM AUTHOR]

microRNAs (miRNAs) perform various oncogenic or tumor suppressor functions in carcinogenesis. Currently, the underlying mechanisms of miRNAs in osteosarcoma (OS) are poorly understood. In the present study, it is demonstrated that expression of miR-544 was markedly upregulated in OS cells and clinical tissues. Furthermore, overexpression of miR-544 enhanced OS cell proliferation in vitro. Bioinformatics analysis indicated that miR-544 may target the 3'-untranslated region of axis formation inhibitor 2, which was validated using luciferase reporter gene assays. The present study demonstrated a vital role for miR-544 in promoting OS cell proliferation, indicating that it may represent a novel prognostic factor or therapeutic target for OS. [ABSTRACT FROM AUTHOR]

To compare the effects of heroin and methamphetamine (METH) addiction on dopamine transporters (DATs) in the same dose and duration, we assessed DAT levels in the striatum by 99m Tc-TRODAT-1 single-photon emission computed tomography (SPECT) brain images in people with heroin and METH dependence. We recruited 21 healthy human controls, 23 heroin-dependent subjects and 25 METH abusers. The heroin- and METH-dependent subjects exhibited negative urine toxicology after undergoing physiological detoxification. All subjects underwent SPECT brain imaging, and specific tracer uptake ratios (SURs) were assessed bilaterally in the regions of interest. A significant SUR reduction in heroin-dependent subjects and METH-dependent subjects compared with healthy controls was found in the left striatum, right striatum, left caudate nucleus, right caudate nucleus, left putamen and right putamen. There were no significant differences in the heroin group and METH group for the left striatum, right striatum, left caudate nucleus, right caudate nucleus, left putamen and right putamen. The scores of craving, HAMA (Hamilton Anxiety Rating Scale), in heroin abusers were lower than in the METH abusers. Our results show that people with heroin and METH dependence who are currently abstinent had lower DAT levels in the striatum than healthy controls. There were no differences in striatal DAT in heroin and METH users. These results suggest that chronic heroin and METH abuse appears to produce similar effects in striatal DAT in humans. METH users may have more serious craving and anxiety symptoms than heroin users with prolonged abstinence. [ABSTRACT FROM AUTHOR]

This study aimed to investigate whether a selective delta opioid receptor agonist, [D-Ala2, D-Leu5]-Enkephalin (DADLE), regulates neurogenesis in the hippocampus of ischemic rats. Using an intracerebral cannula, rats were subjected to cerebral ischemia using the standard four-vessel occlusion. DADLE (2.5 nmol), DADLE (2.5 nmol) with naltrindole (NAL) (2.5 nmol), or vehicle was administered at the onset of reperfusion. Bromodeoxyuridine (BrdU, 100 mg/kg, intraperitoneal) was used to label newly formed cells from days 1 to 7 after ischemia. Immunohistochemistry was used to evaluate cell proliferation and apoptosis and differentiation 7 days 28 days, respectively, after ischemia. Morris water maze test was conducted to test spatial learning and memory 23–27 days after ischemia. We found that DADLE treatment improved performance in the Morris water maze test, promoted proliferation and differentiation of newly formed neurons, and inhibited differentiation into astrocytes in a rat model of cerebral ischemia. Furthermore, the protective effects of DADLE were significantly reversed by co-administration of NAL (P < 0.05), a highly potent and selective delta opioid receptor antagonist. Our findings suggest that DADLE promotes spatial cognitive function recovery and regulates neurogenesis after ischemia, which may provide a promising therapeutic strategy for cerebral ischemia. [ABSTRACT FROM AUTHOR]

Trace-organic contaminants elimination effectiveness and their removal pathways in a powder-activated carbon-membrane bioreactor (PAC-MBR) used for micro-polluted surface water treatment were investigated in this study. The results showed that PAC-MBR was capable of consolidating DOM elimination, enhancing trace-organic contaminants (2,4,6-trichlorophenol, nitrobenzene and trichloroethylene) removal efficiency, improving permeate biostability, and decreasing bulk organic content and specific fractional components, which was beneficial for membrane fouling mitigation. By series of well-designed batch-tests and estimation, trace-organics removal pathways were analyzed. The primary way of TCE removal was aeration volatilization, while that of NB and 2,4,6-TCP elimination was biodegradation which was greatly affected by biomass content within bulk. PAC addition was a positive way for effective trace-organics removal by increasing mixed solid adsorption capability, especially in start-up phase, and offering beneficial circumstances for biomass enrichment and functional bacteria accumulation. Thus, PAC addition into MBR is a simple and effective strategy to treat micro-polluted water resources. [ABSTRACT FROM AUTHOR]

ABSTRACT Membrane fouling caused by natural organic matter is an important problem in drinking water treatment. In this study, bench-scale experiments using three different types of ultrafiltration (UF) membranes were carried out with the surface water of the Songhua River in China in order to investigate the effect of natural organic matter on membrane fouling. Organic matter that caused reversible and irreversible fouling in the filtration operation was desorbed from the fouled membranes and subjected to chemical fractionation and Fourier transform infrared analyses. These analyses revealed that hydrophilic organic matter accounted for the majority of both reversible and irreversible fouling, regardless of the type of membrane. Results also demonstrated that the type of organic matter responsible for fouling differed significantly and depended on the type of membrane. The main types of organic matter that caused reversible fouling were hydrophilic organic matter and hydrophobic acids, for the polyvinyl chloride (PVC) and polysulfone (PS) membranes and hydrophilic matter and weakly hydrophobic acids, for the polyvinylidene fluoride (PVDF) membrane. Hydrophobic acids were largely responsible for the irreversible fouling of PVDF membranes. The PVC membrane was more vulnerable to fouling because of the hydrophilic fraction, and the PS membrane was most easily fouled by the hydrophobic neutral fraction. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Aims. This study was designed to determine if fractional systolic/diastolic pressures act as predictors of the extent of coronary artery disease. Patients and methods. A total of 545 consecutive patients (305 men, 240 women, with mean age 54.2 years) were involved in the study. The patients were diagnosed with coronary and non-coronary artery disease confirmed by angiography. Results. 353 patients were confirmed to have coronary artery disease, with 134 cases involving one vessel, 101 two vessels and 118 three vessels. There were significant differences between brachial and ascending aortic systolic blood pressures, fractional systolic blood pressures and fractional diastolic blood pressures in the patients with coronary artery disease compared with patients with non-coronary artery disease. Blood pressure measured in the brachial artery was higher than the pressure measured in the ascending artery. Ascending aortic fractional systolic/diastolic pressures were associated with coronary Gensini score, and were significantly related to the number of diseased vessels. Conclusions. Fractional systolic and diastolic pressures in the ascending aorta were strong predictive factors for the extent of coronary artery disease. Central pressures measured invasively in the ascending aorta were more predictive than peripheral pressures for the evaluation of coronary artery disease. [ABSTRACT FROM AUTHOR]

Abstract: l-Asparaginase II of E. coli is a kind of effective drug in the treatment of acute lymphoblastic leukaemia. However, during asparaginase therapy, repeated using of the drug is commonly needed because of the enzyme''s relatively short half-life and instability in the processes of production and treatment. This leads to more serious toxic effects on patients. In order to stabilize the enzyme, a higher thermostable mutant l-asparaginase II was created in the present study by replacing Asp178 with proline in a hydrogen-bonded turn (178–180DGR) which is contribute to the thermostability of the enzyme. The results displayed that values of K m and K cat for the mutant enzyme are not affected although the energy of activation is increased comparing to the wild-type enzyme. These data suggest that such alteration for l-asparaginase II enhances the thermostability of the enzyme without changing the enzyme''s activity and thus the therapeutical use of l-asparaginase II might be benefit from these results. [Copyright &y& Elsevier]