Search

The difference effect and hydrogen evolution behavior of pure Mg in alkaline NH4+ containing solutions are systematically investigated. The Mg electrode exhibits a positive difference effect, rather the traditional negative difference effect, with the anomalous hydrogen evolution in the alkaline 0.1 M (NH4)2SO4, 0.1 M NH4HCO3 and 0.05 M (NH4)2CO3 solutions. This is primarily attributed to the corrosion product film dissolution effect of NH4+ and the formation of the black corrosion products. The hydrogen evolution kinetics with the difference effects are deduced and explained by the prevailing incomplete film Mg+ mechanism and enhanced catalytic activity mechanism. [ABSTRACT FROM AUTHOR]

To serve in a more aggressive chlorine (Cl−) ions-containing environment, a chlorine ions insensitivity Mg-Nd-Zr alloys is fabricated, exhibiting a stable corrosion resistance in either 3.5wt.% or 10 wt.% NaCl solution. Unlike pure Mg who exhibit a negligible protection of the matrix, a distinct "hindering effect" of Cl− diffusion caused by doping elements within the corrosion film was observed. Its underlying mechanism is demonstrated by X-ray photoelectron spectroscopy (XPS) and Density functional theory (DFT) analysis. The introducing with Nd and Zr elements can effectively passivate vacancies and alter diffusion energy of chlorine ions. [ABSTRACT FROM AUTHOR]

Deep convolutional neural networks (DCNNs) have demonstrated promising performance in classifying breast lesions in 2D ultrasound (US) images. Exiting approaches typically use pre-trained models based on architectures designed for natural images with transfer learning. Fewer attempts have been made to design customized architectures specifically for this purpose. This paper presents a comprehensive evaluation on transfer learning based solutions and automatically designed networks, analyzing the accuracy and robustness of different recognition models in three folds. First, we develop six different DCNN models (BNet, GNet, SqNet, DsNet, RsNet, IncReNet) based on transfer learning. Second, we adapt the Bayesian optimization method to optimize a CNN network (BONet) for classifying breast lesions. A retrospective dataset of 3034 US images collected from various hospitals is then used for evaluation. Extensive tests show that the BONet outperforms other models, exhibiting higher accuracy (83.33%), lower generalization gap (1.85%), shorter training time (66 min), and less model complexity (approximately 0.5 million weight parameters). We also compare the diagnostic performance of all models against that by three experienced radiologists. Finally, we explore the use of saliency maps to explain the classification decisions made by different models. Our investigation shows that saliency maps can assist in comprehending the classification decisions. [ABSTRACT FROM AUTHOR]

The carbon nanotubes (CNTs) mixing inside a joint between two fastened parts of the material is the key to realize balance of strength and elongation. The electrophoretic deposition was innovatively applied to friction stir butt welding Mg plates to form CNTs/Mg joints. The results showed that the CNTs was involved to the adjacency of the butt weld mixing zone (BWMZ) by a concave shoulder and will be brought into the BWMZ through the forward force of the conical probe. Two pieces of plates deposited with CNTs were jointed without defects at various welding speeds through the advanced solid-phase joining techniques (electrophoretic deposition assisted with friction stir butt welding). When compared to the CNTs/Mg joint, the grains of the joint without CNTs were coarser and more aeolotropic. CNTs can generate Orowan strengthening due to confinement effect of dislocations slip, and CNTs with a high specific surface area also can serve as contact interface, leading to resistance at for localized plastic deformation, and with the increase of the total grain boundary, the strengthening effect becomes predominant. When bonding between matrix and CNTs was tight, the hard CNTs were difficultly pulled out from joint and then breaking energy will be absorbed and help to hinder crack propagation and expansion, which results in decent elongation. Consequently, CNTs mixed joint exhibits more balanced tensile properties compared to traditional joints. [ABSTRACT FROM AUTHOR]

The adsorption energy of F, H on the titanium surface with 46 doping elements was calculated in the first-principles approach. Compared with Ti in fuel cell environment, the adsorption energy would decrease with the doping of C, N, etc., while increasing with Be, Mg, etc. doping. The increase of adsorption energy will improve corrosion resistance, and testified by the previous research, so as to provide guidance for the design of corrosion-resistant Ti alloy bipolar plates. [ABSTRACT FROM AUTHOR]

Current jamming strategy generation in communication relies on prior information or has a slow learning rate. To overcome these drawbacks, an intelligent strategy generation algorithm is proposed. This paper first creates a jamming strategy space which has three dimensions: jamming power, modulation, and duty cycle. Then, a communication jamming reward function is constructed and its property of continuity is proved. The proof of continuity provides the theoretical basis for optimization. Then, the local boundedness of the reward function in the strategy space is demonstrated. Finally, an intelligent algorithm for jamming strategy generation in communication is introduced based on the multiarmed bandit framework. Compared with the current algorithm, the new one can significantly improve the optimization speed by enlarging its exploring area from one point to a certain region. Simulations show that, by using the regional exploration, this algorithm can explore much more jamming strategies compared with the existing methods in the equal training cycles, and learn the optimal jamming strategy faster. [ABSTRACT FROM AUTHOR]

The coexistence of superconductivity and charge inhomogeneity was observed in many cuprate superconductors. The relationship between those two is still controversial. Similarly, in the graphene sheets of the intercalated graphitic superconductor CaC6, the charge inhomogeneity was also observed. We simulate such a system by constructing the Hubbard model on the honeycomb lattice with charge inhomogeneity imposed by force. Utilizing the finite-temperature determinant quantum Monte Carlo algorithm, we examine the relationship between the superconducting pairing and the charge inhomogeneity. An optimal charge inhomogeneity for the d+id-wave pairing is found. While for other artificial charge inhomogeneities, the d+id-wave pairing is monotonically suppressed. The possible π-phase shift induced by charge inhomogeneity is also examined. [ABSTRACT FROM AUTHOR]

The effects of carbon distribution on the microstructure and thermal conductivity of ductile iron were investigated in the present study. The microstructure of as-cast and quenched ductile iron were characterized by OM and SEM. Results showed that the microstructure of as-cast ductile iron was composed of spheroidal graphite, ferrite with the volume of 80%, and a small amount of pearlite, and quenched ductile iron was composed of spheroidal graphite, coarse/fine acicular martensite (αM phase) and high-carbon retained austenite (γ phase). The volume fraction of retained austensite and its carbon content for direct quenched ductile iron and tepmered ductile iron were quantitatively analysed by XRD. Results revealed that carbon atoms diffused from αM phase to γ phase during tempering at low temperatures, which resulted in carbon content in retained γ phase increasing from 1.2 wt% for the direct quenched sample to about 1.9 wt% for the tempered samples. Consequently, the lattice distortion was significantly reduced and gave rise to an increase of thermal conductivity for ductile iron. [ABSTRACT FROM AUTHOR]

Using determinant quantum Monte Carlo algorithm, we study the superconducting d-wave pairing and antiferromagnetic order on the coupled Hubbard ladders. With the presence of the next-nearest-neighbor hopping t ′ = - 0.25 , we find that, when the hopping strength among ladders decreases, the d-wave pairing is firstly enhanced and then gets suppressed, showing an optimal hopping inhomogeneity for the d-wave pairing. Without the next-nearest-neighbor hopping, however, the d-wave pairing is suppressed monotonically, i.e., no optimal inhomogeneity exists. We also measure the antiferromagnetic structure factor, which also presents an optimal inhomogeneity with the next-nearest-neighbor hopping t ′ = - 0.25 , and no such optimal inhomogeneity when t ′ = 0.0 . The effect of different temperature, interaction strength, electron density, and lattice size is carefully studied and discussed. [ABSTRACT FROM AUTHOR]

Although the synaptic alterations associated with the stress-related mood disorder major depression has been well-documented, the underlying transcriptional mechanisms remain poorly understood. Here, we perform complementary bulk nuclei- and single-nucleus transcriptome profiling and map locus-specific chromatin interactions in mouse neocortex to identify the cell type-specific transcriptional changes associated with stress-induced behavioral maladaptation. We find that cortical excitatory neurons, layer 2/3 neurons in particular, are vulnerable to chronic stress and acquire signatures of gene transcription and chromatin structure associated with reduced neuronal activity and expression of Yin Yang 1 (YY1). Selective ablation of YY1 in cortical excitatory neurons enhances stress sensitivity in both male and female mice and alters the expression of stress-associated genes following an abbreviated stress exposure. These findings demonstrate how chronic stress impacts transcription in cortical excitatory neurons and identify YY1 as a regulator of stress-induced maladaptive behavior in mice. The mechanisms underlying the chronic stress-induced increased risk for major depressive disorder and anxiety are unclear. Here, the authors show the transcriptional changes occurring in neocortical neurons and identify YY1 as a regulator of chronic stress-induced maladaptive behavior in mice. [ABSTRACT FROM AUTHOR]

Magnesium alloys with high strength and excellent corrosion resistance are always sought-after in light-weighting structural components for automotive and aerospace applications. However, for most magnesium alloys that have a high specific strength, they usually have an inferior corrosion resistance and vice versa. In this work, we successfully develop a Mg-11Y-1Al (wt. %) alloy through conventional casting, solution treatment followed by extrusion. The overall properties of this alloy feature with a corrosion rate lower than 0.2 mm y−1, high yield strength of 350 MPa and moderate tensile elongation of 8%, the combination of which shows competitive advantage over other comparative magnesium alloys in the literature. It is found that a thin and dense protective film of Y2O3/Y(OH)3 can be fast developed with the aid of Al2O3/Al(OH)3 deposition to isolate this alloy from further attack of corrosion medium. Meanwhile, the refined grains, weak texture and activation of non-basal slip systems co-contribute to the high strength and good ductility. Our findings are expected to inspire the design of next-generation high performance magnesium alloys. High-strength Mg alloys are often sought-after for automotive and aerospace applications, but they have an inferior corrosion resistance. Here, the authors develop a Mg-11Y-1Al (wt. %) alloy that shows both significantly improved mechanical properties and corrosion resistance. [ABSTRACT FROM AUTHOR]

Purpose: The aim was to explore the clinical efficacy of ranibizumab combined with surgical treatment of neovascular glaucoma with vitreous hemorrhage. Materials and Methods: A total of 15 patients (17 affected eyes) who had neovascular glaucoma (NVG) with vitreous hemorrhage in our hospital were enrolled. After admission, the patient was given levofloxacin eye drops, 4 times a day. Three days later, the patients received intravitreal injection of ranibizumab. Then, trabeculectomy and vitrectomy were performed. The detailed clinical data, such as type of diseases, intraocular pressure (IOP), and best corrected visual acuity (BCVA), were collected before and after surgery. Results: Visual acuity remained stable or improved in thirteen effected eyes and decreased in effected three eyes. Within 30 days after discharge, one effected eye recurred iris neovascularization with slightly higher IOP; then, the patient received intravitreal injection of ranibizumab again and neodymium-doped yttrium aluminum garnet (YAG) therapy. One patient (one effected eye) was given intravitreal ranibizumab injection again because of uncontrollable IOP and recurrence of neovascularization on iris surface and angle after operation; then, the patient received cyclophotocoagulation. Vitreous cavity hemorrhage occurred again in 3 patients after operation; then, these patients received the vitreous cavity lavage again. After trabeculectomy, inflammatory exudation or a small amount of bleeding could be seen in the anterior chamber of 6 young patients. Conclusion: Intravitreal injection of ranibizumab can effectively promote the rapid regression of intraocular neovascularization and help to control the IOP and improve postoperative visual acuity. [ABSTRACT FROM AUTHOR]

Quantum phase transitions in quantum matter occur at zero temperature between distinct ground states by tuning a nonthermal control parameter. Often, they can be accurately described within the Landau theory of phase transitions, similarly to conventional thermal phase transitions. However, this picture can break down under certain circumstances. Here, we present a comprehensive study of the effect of hydrostatic pressure on the magnetic structure and spin dynamics of the spin-1/2 ladder compound C9H18N2CuBr4. Single-crystal heat capacity and neutron diffraction measurements reveal that the Néel-ordered phase breaks down beyond a critical pressure of Pc ∼ 1.0 GPa through a continuous quantum phase transition. Estimates of the critical exponents suggest that this transition may fall outside the traditional Landau paradigm. The inelastic neutron scattering spectra at 1.3 GPa are characterized by two well-separated gapped modes, including one continuum-like and another resolution-limited excitation in distinct scattering channels, which further indicates an exotic quantum-disordered phase above Pc. There is a class of quantum phase transitions that do not fit into the traditional Landau paradigm, but are described in terms of fractionalized degrees of freedom and emergent gauge fields. Hong et al. find evidence of such a transition in a molecular spin-1/2 antiferromagnetic ladder compound under hydrostatic pressure. [ABSTRACT FROM AUTHOR]

The role of alloyed Sc on the corrosion behavior of Mg was revealed using an understanding of the anodic and cathodic kinetics derived from experimental measurements and DFT calculations. After T4 solution treatment, the Mg–Sc alloy exhibited higher corrosion resistance than high pure Mg. The scandium oxide-rich surface layers formed on the T4 Mg–Sc alloy seemed to suppress anodic dissolution by being protective, and the addition of Sc could inhibit cathodic hydrogen evolution. [ABSTRACT FROM AUTHOR]

Introduction and hypothesis: Studies on the imaging of female periurethral masses are sparse, and most are focused on cystic lesions. In this article, we studied female periurethral solid masses and reported their ultrasonographic features. Methods: Fifteen women with periurethral solid masses pathologically diagnosed between January 2008 and April 2021 were assessed. Results: Each patient had only one mass. The pathological types included urethral caruncle (5 patients), urethral leiomyoma (3 patients), urethral malignant tumor (MT) (3 patients), periurethral spindle tumor (3 patients) and cartilage necrosis of pubic symphysis (PS) (1 patient). On ultrasound, all urethral caruncles were located at the urethral meatus. They were hypoechoic/isoechoic and rich in blood flow signal. Each leiomyoma presented as a well-defined hypoechoic mass with an oval shape. The urethral MT had inhomogeneous/isoechoic echoes, with medium to abundant blood flow signal. The spindle cell tumors had regular/irregular shapes, moderate/high density echogenicity and little/rich blood flow signals. The articular cartilage necrosis of PS was regular in shape, with mixed echogenicity and no blood flow. Conclusions: Ultrasound imaging is a convenient and useful method to evaluate the morphological characteristics of female periurethral solid masses. [ABSTRACT FROM AUTHOR]

Inverse-electron-demand-hetero-Diels-Alder reactions of alkenes with α,β-unsaturated keto compounds allow rapid access to the tetrahydropyran ring found in numerous natural products and bioactive molecules. Despite its synthetic interest, catalytic asymmetric versions of this process remain underdeveloped, especially regarding the use of non-activated alkenes reacting with α,β-unsaturated ketone or aldehyde, for which no report can be found in the literature. Herein, we describe the catalytic inverse-electron-demand-hetero-Diels-Alder reactions between neutral alkenes and an α,β-unsaturated ketones or aldehydes to produce a variety of trans-fused [5,6,8] tricyclic structures containing a central, chiral tetrahydropyran ring. This complex transformation, which is achieved using a chiral phosphoric acid, allows for the formation of four stereogenic centers in a single step with high regio-, diastereo- and enantioselectivity (up to 99% ee). Such level of stereocontrol could be achieved by a key remote double hydrogen atom bonding interaction between the linear substrate and the catalyst. Although the hetero-Diels–Alder reaction is a staple of organic chemistry, catalytic asymmetric versions of the inverse-electron demand variant often require specially engineered substrates for the reaction to work. Here the authors cyclize non-activated alkenes with α,β-unsaturated ketones or aldehydes to form chiral fused heterocycles using a chiral phosphoric acid catalyst. [ABSTRACT FROM AUTHOR]

Loop closure detection is an indispensable part of visual simultaneous location and mapping (SLAM). Correct detection of loop closure can help mobile robot to reduce the problem of cumulative pose drift. At present, the main method for detecting visual SLAM loop closure is the bag of words (BoW) model, but it lacks the spatial distribution information of local features of the image, and the scale will become larger and larger with the increase of data, resulting in the slow operation speed. In order to solve these problems, the image histogram and the key region covariance matrix matching method are used to visually detect the loop closure combined with the global and local image features. In this paper, three different place recognition techniques are studied: histogram only, image covariance matrix matching (ICMM) and cluster loop. Experiments on real datasets show that the proposed method of detecting the loop closure is better than the traditional methods in detecting accuracy and recalling rate, which also improves the operation effect of the SLAM algorithm. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Online customers execute transactions without inspecting products could expect to encounter risks of receiving products with unsatisfactory qualities, especially in food transactions. Thus quality supervision plays a key role in the establishment of trust as well as in the management of risk between online customers and sellers. Most papers in this field are in qualitative nature. In this paper, a quality supervision profit (QSP) model is formulated as a discrete-time optimal control problem. It is a quantitative approach, and it broadens the scope of current research in the area. The quality effort level of online sellers (QELs) and the quality supervision level of the electronic intermediary (QSLm) are considered together with their corresponding profit in the proposed model. The aim is to optimize an overall profit. A case study arising from Suichang's food traceability system (FTS) of farm produce online transaction is carried out in details. The results reveal that QELs, QSLm and the profit distribution coefficient have a strong influence upon the profits of both sides. Finally, some concluding remarks, including potential further research topics, are given. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Central South University is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective: The aim of this study is to clone the LpxA gene of Chlamydia trachomatis and analyze its biological characteristics. Methods: Specific primers were designed according to the sequence of Ct LpxA gene. LpxA gene was amplified by PCR and connected to pMD18-T vectors. Positive clones were selected for PCR and DNA sequencing. Finally, bioinformatics software was used to analyze the biological properties of LpxA protein. Results: The total length of LpxA gene was 840 bp, encoding 280 amino acids. LpxA protein has no signal peptide and was located in bacterial cytoplasm. The prediction of secondary structure showed that the α-helix, extended strand, β-turn and random coil accounted for 19.6%, 32.8%, 11.4% and 36%, respectively. According to the prediction of tertiary structure, three identical LpxA molecules constituted homologous trimers. It was predicted that there were 11 B cell epitopes in LpxA. Conclusion: Ct Lpxa gene was cloned, and LpxA protein structure and function were predicted. [ABSTRACT FROM AUTHOR]

Purpose: To study the effect of curcumin on proliferation and invasion of the human retinoblastoma cells and its potential mechanism. Methods: A cell line of retinoblastoma (WERI-Rb-1) was treated with various concentrations of curcumin (0–40 µM). Cell number was counted with CCK8 kit, and cell migration was assessed using the Transwell assay. Immunoblotting was performed to detect the proteins of metalloproteinase-2 (MMP-2), MMP-9 and vascular endothelial growth factor (VEGF) as well as nuclear translocation of nuclear factor-κB (NF-κB, p65). Results: Proliferation and migration of WERI-Rb-1 cells were significantly inhibited by curcumin in a concentration-dependent manner (0–40 µM). Protein expressions of MMP-2, MMP-9 and VEGF in the WERI-Rb-1 cells were also significantly inhibited by curcumin in a concentration-dependent manner (0–40 µM). Furthermore, nuclear translocation of NF-κB (p65) was significantly inhibited by curcumin in time-dependent manner (6–24 h). Conclusion: Curcumin inhibited proliferation and migration of WERI-Rb-1 cells, a cell line of human retinoblastoma, which might be through modulating NF-κB and its downstream proteins including VEGF, MMP-2, and MMP-9. [ABSTRACT FROM AUTHOR]

The oxidation mechanism for the molten surface of Al–5Mg–2Si–Mn alloy was studied. The results show that the oxide layer contains MgO, Al2O3, MgAl2O4, BeO and SiO2, and it is composed of a composite inner layer (MgO/Al2O3/MgAl2O4/BeO/SiO2) and an outer layer of MgO. An oxidation mechanism was proposed to describe the four oxidation stages which included oxidation adsorption, accelerated oxidation, transitional oxidation and stable oxidation. The effects of oxidation time and oxidation temperature on the thickness of oxide layer were discussed. Thermodynamic calculations were used to confirm the feasibility of oxidation process, indicating that MgO was the most stable oxide in the experimental temperature range. Further, the stable regions of MgO and MgAl2O4 as functions of magnesium content and oxidation temperature were calculated. In the stable oxidation stage, the diffusion activation energy of Mg atoms in MgO was fitted according to the outer layer thicknesses, and the kinetic equation of the outer layer thickness with the oxidation time and oxidation temperature was established. From the perspective of thermodynamics and kinetics, the oxidation products of the alloy during the melting process and the effects of oxidation time and temperature on the oxide layer were analyzed. [ABSTRACT FROM AUTHOR]

In the mining process of deep metal mines, different types of rock mass instability failures are caused by strong mining disturbance. It is beneficial to master the fracture mechanism of rock mass in time to effectively prevent and control the ground pressure disasters. Microseismic signals are generated by the propagation and expansion of cracks inside the rock mass that contain plentiful information about the structural changes of rock mass. The ratio of the radiated energy of S and P waves (Es/Ep) of microseismic events can fast and effectively calculate the rock fracture mechanism, which is widely used for ground pressure hazard risk assessment. In this paper, this method was used to analyze the fracture mechanism of rock mass around deep stope in Hongtoushan copper mine and Ashele copper mine. Furthermore, the spatial distribution characteristics and proportion changes of microseismic events with different fracture mechanisms along with the mining process were studied. The results show that tensile cracks play a dominant role, accounting for 62% of the total events, during non-shear fracturing of the rock mass caused by the stoping unloading effect, while shear cracks occupy 68% of the total events during orebody slip failure. When the physical and mechanical properties of the orebody and rock mass are significantly different, slip failure along their contact zone is prone to occur under blasting disturbance. During deep mining, it is necessary to control the exposed area of the roof by each stoping, especially during the earlier mining stage, to avoid tensile stress concentration. The temporal and spatial variation of tension cracks and shear cracks induced by roof damage obtained in this paper can guide the prevention and control of ground pressure disasters in deep mining effectively. [ABSTRACT FROM AUTHOR]

Purpose: To explore the value of high-frequency two-dimensional (2D) ultrasound on demonstrating the morphology of puborectalis muscle and detect muscle avulsion.Methods: High-frequency 2D ultrasound and tomographic ultrasound image (TUI) were peformed to demonstrate puborectalis muscle and detect muscle avulsion respectively among 158 women with or without significant pelvic organ prolapse (POP) (POP quantification grade 2 or higher). Mean values were compared using student's t test between women with or without avulsion defects. We performed Cohen's Kappa analysis to examine the test agreement between high-frequency 2D ultrasound and TUI mode. Pearson correlation analysis was performed to explore the relationship between the thickness of puborectalis muscle and the measurements of levator-urethra gap (LUG).Results: The result of high-frequency 2D ultrasound in detecting muscle avulsion agreed well with TUI mode (Kappa 0.88, P < 0.05). Women with muscle avulsion had thinner muscles and larger LUG measurements than those with normal muscle insertion (P < 0.05). Pearson correlation analysis revealed the negative relationship between the thickness of puborectalis muscle and LUG measurements (r = - 0.73).Conclusion: The study confirmed that it was feasible to observe the morphology of puborectalis muscle and detect muscle avulsion by high-frequency 2D ultrasound. [ABSTRACT FROM AUTHOR]

With the help of density functional theory (DFT) calculations, Mg-Sc-Y alloys with various Y content were designed and produced. The single-phase Mg-Sc-Y alloys were composed of a typical peritectic microstructure with internal Sc-rich zones surrounded by Y-rich zones. With increasing Y content, the hydrogen evolution rates decreased significantly to 0.13 mL/cm2/day and increased slightly afterward. This was attributed to the combined effect of a decrease in the thermodynamic driving force for corrosion, surface layer improvement, and an increase in the number of galvanic couples between the Sc-rich and Y-rich zones. [ABSTRACT FROM AUTHOR]

Introduction and hypothesis: To explore the feasibility of three-dimensional (3D) transperineal tomographic ultrasound in evaluating pelvic floor support of the urethra in women. Methods: Three-dimensional transperineal ultrasound volume data sets of 50 women with stress urinary incontinence (SUI) and 25 women without SUI were obtained for analysis. Pelvic floor support of the urethra was evaluated by studying the relationship between the urethra and vagina in vaginal cross section and quantified by estimating the urethral depression (UD) rate. The extent of paravaginal support at level II was also evaluated in tomographic ultrasound imaging (TUI) mode in all participants. Two-sample t-test and Mann-Whitney U test were used for statistical analysis. Results: The extent of paravaginal support at level II showed no difference between the two groups. Posterior depression of the urethra into the anterior vaginal wall was increased in SUI (P < 0.05). When the UD rate value was 0.53 (CI 85%) combined with three continuous "abnormal slices," the maximum Youden Index value (sensitivity 0.82, specificity 0.88) was obtained to screen dysfunctional support of the urethra. Conclusions: The pelvic floor support of the urethra can be evaluated indirectly by studying the relationship between the urethra and anterior vaginal wall in the vaginal cross section by TUI. The obvious posterior depression of the urethra into the anterior vaginal wall could be indirect evidence of a defect in the support of the urethra. [ABSTRACT FROM AUTHOR]

Mg alloys containing long-period stacking-ordered (LPSO) phases often display excellent mechanical properties. The underlying mechanism is yet unclear. In this work, in situ synchrotron X-ray diffraction was employed to study tensile deformation of a Mg97Y2Zn alloy that contains 18R-type LPSO phase. From lattice strain measurement, it is found that the LPSO phase has a similar elastic modulus as Mg. After material yielding, lattice strain in the Mg phase decreased, while lattice strain in the LPSO phase increased further. By analyzing the lattice strain evolution of different Mg peaks, basal slip and deformation twinning are identified as the dominant deformation mechanisms. This finding is further confirmed by surface slip trace analysis using electron backscattered diffraction (EBSD). Additional analysis of diffraction peak broadening indicates a continuous increase of dislocation density during plastic deformation. Based on the above results, it can be concluded that the interdendritic LPSO phase behaves like a reinforcing phase that directly strengthens the material. The high tensile ductility of the material is attributed to the weak extrusion texture caused by the presence of interdendritic LPSO. In addition, small LPSO plates inside the Mg phase can serve as dislocation nucleation sites, which leads to a high work hardening rate in the material. [ABSTRACT FROM AUTHOR]

The dimension of the levator hiatus is a possible predictor of pelvic organ prolapse (POP). This retrospective study investigated 360 women who went to urogynecological clinic for pelvic floor discomfort. Levator hiatus dimensions were obtained by three-dimensional transperineal ultrasound and results were compared between women with and without significantly objective prolapse (International Continence Society POP quantification, grade 2 or higher). Receiver operating characteristic (ROC) curve analyses were performed to determine valid screening index for detecting abnormal levator hiatus distensibility. Women with significantly objective prolapse had significantly higher levator hiatus dimensions than those without (all P < 0.001). ROC curve analyses confirmed that hiatal area (HA) of 19.5 cm2 during Valsalva maneuver can be used as single-screening index for abnormal levator hiatus distensibility with sensitivity of 0.80 and specificity of 0.70. In this study, we used a two-step method and achieved higher sensibility (0.80 vs. 0.87) without reducing specificity (0.70 vs. 0.71) compared with a single-screening index method. As a result, we suggest that HA ⩾ 19.5 cm2 during Valsalva maneuver is an indicator of abnormal levator hiatus distensibility in Chinese women and that the two-step method has higher sensitivity in detecting abnormal distensibility. [ABSTRACT FROM AUTHOR]

Objective: To explore the feasibility of three-dimensional (3D) transperineal ultrasound on the observation of paravaginal support in nulliparous and postpartum women.Methods: Volume datasets were acquired in 50 nulliparous and 100 postpartum women using 3D transperineal ultrasound. Paravaginal supports were observed by studying the vaginal cross-sectional morphology. The extent of paravaginal support in specific level were evaluated by counting out at a 2 mm interval in tomographic ultrasound imaging mode in all subjects. The Mann-Whitney U test were applied to establish comparisons between the two groups.Results: Three representative manifestations of vaginal cross-sectional morphology corresponding to different paravaginal support were presented from the dorsal side to the caudal side, both in nulliparous women and postpartum women. The extent of paravaginal support in middle vagina was 11 slices (range 9-12) in nulliparous women and 7 slices (range 4-10) in postpartum women (P < 0.05).Conclusion: This pilot study confirmed that it was feasible to indirectly study paravaginal support by observing the vaginal cross-sectional morphology using 3D transperineal ultrasound. [ABSTRACT FROM AUTHOR]

Tin and its compounds hold promise for the development of high-capacity anode materials that could replace graphitic carbon used in current lithium-ion batteries. However, the introduced porosity in current electrode designs to buffer the volume changes of active materials during cycling does not afford high volumetric performance. Here, we show a strategy leveraging a sulfur sacrificial agent for controlled utility of void space in a tin oxide/graphene composite anode. In a typical synthesis using the capillary drying of graphene hydrogels, sulfur is employed with hard tin oxide nanoparticles inside the contraction hydrogels. The resultant graphene-caged tin oxide delivers an ultrahigh volumetric capacity of 2123 mAh cm–3 together with good cycling stability. Our results suggest not only a conversion-type composite anode that allows for good electrochemical characteristics, but also a general synthetic means to engineering the packing density of graphene nanosheets for high energy storage capabilities in small volumes. [ABSTRACT FROM AUTHOR]

A surface crack defect is normally found in low pressure castings of Al alloy with a sudden contraction structure. To further understand the formation mechanism of the defect, the mold filling process is simulated by a two-phase flow model. The experimental results indicate that the main reason for the defect deformation is the mismatching between the height of liquid surface in the mold and pressure in the crucible. In the case of filling, a sudden contraction structure with an area ratio smaller than 0.5 is obtained, and the velocity of the liquid front increases dramatically with the influence of inertia. Meanwhile, the pressurizing speed in the crucible remains unchanged, resulting in the pressure not being able to support the height of the liquid level. Then the liquid metal flows back to the crucible and forms a relatively thin layer solidification shell on the mold wall. With the increasing pressure in the crucible, the liquid level rises again, engulfing the shell and leading to a surface crack. As the filling velocity is characterized by the damping oscillations, surface cracks will form at different heights. The results shed light on designing a suitable pressurizing speed for the low pressure casting process. [ABSTRACT FROM AUTHOR]

The effects of the size of micron SiC particle (SiCp) on the grain refinement, distribution of particle and tensile properties of as-cast AZ31B (Mg-3Al-1Zn-0.3Mn) magnesium matrix composites have been investigated. As the volume fraction of micron SiCp increases to 15 vol%, excellent grain refinement is achieved. Meanwhile, volume fraction of particle is set as same content, grain size of matrix decreases as the size of micron SiCp decreases. This is due to both the uniform distribution and refining effect of the fine particles. The micron SiCp distributes along the grain boundaries. Because of grain refinement strengthening and ceramic phase strengthening effects, the room temperature tensile property of M5-15 has the optimal value of YS 171MPa-UTS 216MPa-EL 0.87 %. [ABSTRACT FROM AUTHOR]

Eubacterium limosum ZL-II was described to convert secoisolariciresinol (SECO) to its demethylating product 4,4′-dihydroxyenterodiol (DHEND) under anoxic conditions. However, the reaction cascade remains unclear. Here, the O-demethylase being responsible for the conversion was identified and characterized. Nine genes encoding two methyltransferase-Is (MT-I), two corrinoid proteins (CP), two methyltransferase-IIs (MT-II), and three activating enzymes (AE) were screened, cloned, and expressed in Escherichia coli. Four of the nine predicted enzymes, including ELI_2003 (MT-I), ELI_2004 (CP), ELI_2005 (MT-II), and ELI_0370 (AE), were confirmed to constitute the O-demethylase in E. limosum ZL-II. The complete O-demethylase (combining the four components) reaction system was reconstructed in vitro. As expected, the demethylating products 3-demethyl-SECO and DHEND were both produced. During the reaction process, ELI_2003 (MT-I) initially catalyzed the transfer of methyl group from SECO to the corrinoid of ELI_2004 ([Co]-CP), yielding demethylating products and [CH-Co]-CP; then ELI_2005 (MT-II) mediated the transfer of methyl group from [CH-Co]-CP to tetrahydrofolate, forming methyltetrahydrofolate and [Co]-CP. Due to the low redox potential of [Co]/[Co], [Co]-CP was oxidized to [Co]-CP immediately in vitro, and ELI_0370 (AE) was responsible for catalyzing the reduction of [Co]-CP to its active form [Co]-CP. The active-site residues in ELI_2003, ELI_2005, and ELI_0370 were subsequently determined using molecular modeling combined with site-directed mutagenesis. To our knowledge, this is the first study on the identification and characterization of a four-component O-demethylase from E. limosum ZL-II, which will facilitate the development of method to artificial synthesis of related bioactive chemicals. [ABSTRACT FROM AUTHOR]

Background: Epigenomic reconfiguration, including changes in DNA methylation and histone modifications, is crucial for the differentiation of embryonic stem cells (ESCs) into somatic cells. However, the extent to which the epigenome is reconfigured and the interplay between components of the epigenome during cellular differentiation remain poorly defined. Methods: We systematically analyzed and compared DNA methylation, various histone modification, and transcriptome profiles in ESCs with those of two distinct types of somatic cells from human and mouse. Results: We found that global DNA methylation levels are lower in somatic cells compared to ESCs in both species. We also found that 80% of regions with histone modification occupancy differ between human ESCs and the two human somatic cell types. Approximately 70% of the reconfigurations in DNA methylation and histone modifications are locus- and cell typespecific. Intriguingly, the loss of DNA methylation is accompanied by the gain of different histone modifications in a locus- and cell type-specific manner. Further examination of transcriptional changes associated with epigenetic reconfiguration at promoter regions revealed an epigenetic switching for gene regulation-a transition from stable gene silencing mediated by DNA methylation in ESCs to flexible gene repression facilitated by repressive histone modifications in somatic cells. Conclusions: Our findings demonstrate that the epigenome is reconfigured in a locus- and cell type-specific manner and epigenetic switching is common during cellular differentiation in both human and mouse. [ABSTRACT FROM AUTHOR]

The effects of the volume ratios of micro and nano-SiC particles (SiCp) on the grain refinement, distribution of SiCp particle, and tensile properties of the as-cast AZ31B (Mg-3Al-1Zn-0.3Mn) magnesium-based metal matrix composites have been investigated. As the volume fraction of micron SiCp decreases to 9 vol.% and the nano-SiCp increases to 1 vol.%, excellent grain refinement effect is achieved. This is due to both the uniform distribution and refining effects of micro- and nano-SiCp. Moreover, the micron SiCp distribute along the grain boundaries, while nano-SiCp is mainly distributed around the micron SiCp. The room-temperature tensile results show that the optimal room-temperature yield and tensile strengths are achieved with a 9/1 ratio of micro to nano-SiCp, while the 9.5/0.5 ratio yielded the highest elongation. [ABSTRACT FROM AUTHOR]

Fruit is one of the most commonly reported food allergy sources in China, and peach lipid transfer protein (Pru p 3) has been identified as the major allergen inducing systematic symptoms. Crude allergen extracts and single component allergens have been used in food allergy diagnosis and immunotherapy. Reliable and sensitive analytical methods to quantify Pru p 3 content in fruit will help to identify low-allergenic cultivars among the abundant peach genetic resources in China. In this study, we developed a sensitive sandwich ELISA method to measure Pru p 3 in peach fruit based on two monoclonal antibodies with high sensitivity and linearity. Significant variability was observed in peach cultivars, with a much higher Pru p 3 level in peach peel than in pulp. This method will be very useful to select peach varieties with low Pru p 3 content and as a diagnostic product to detect hidden allergens in processed food. [ABSTRACT FROM AUTHOR]

The quantum entanglement between two qubits is crucial for applications in the quantum communication. After the entanglement of photons was experimentally realized, much effort has been taken to exploit the entangled electrons in solid-state systems. Here, we propose a Cooper-pair splitter, which can generate spatially-separated but entangled electrons, in a quantum anomalous Hall insulator proximity-coupled with a superconductor. After coupling with a superconductor, the chiral edge states of the quantum anomalous Hall insulator can still survive, making the backscattering impossible. Thus, the local Andreev reflection becomes vanishing, while the crossed Andreev reflection becomes dominant in the scattering process. This indicates that our device can serve as an extremely high-efficiency Cooper-pair splitter. Furthermore, because of the chiral characteristic, our Cooper-pair splitter is robust against disorders and can work in a wide range of system parameters. Particularly, it can still function even if the system length exceeds the superconducting coherence length. [ABSTRACT FROM AUTHOR]

Motivated by the desire of process simplicity and feasibility for 2.5D/3D integration, a novel interposer technique with polymer liner and silicon pillars of ultra-low-resistivity as through-silicon-vias (TSVs) is proposed in this paper. Silicon pillars with ultra-low-resistivity, instead of conventionally electroplating copper posts, are utilized as vertical via conductors, and low-k polymer Benzocyclobutene, other than silicon dioxide (SiO), is used to form liners. Fabrication techniques and electrical characteristics of the proposed interposer are illustrated. Test vehicles are successfully fabricated and their electrical characteristics including DC resistance and leakage current are measured. The results show that the DC resistances of the proposed TSVs are averaged at 5.94, 2.68 and 1.72 Ω for silicon pillars with diameters of 10, 20 and 30 μm respectively. Also, with a DC bias voltage of 10 V, the leakage current between TSV to silicon substrate is as low as 6.79 pA. These elementary results illustrate the simplicity, feasibility and high reliability of the proposed interposer structure. [ABSTRACT FROM AUTHOR]

The present study is an attempt to formulate the three-dimensional quantitative structure-activity relationship (3D-QSARs) modeling of 3-benzimidazol-2-ylhydroquinolin-2-one derivatives inhibiting vascular endothelial growth factor receptor-2 (VEGFR-2) tyrosine kinase. The 3D-QSARs were established for 36 3-benzimidazol-2-ylhydroquinolin-2-one derivatives as VEGFR-2 tyrosine kinase inhibitors using comparative molecular field analysis (CoMFA) and comparative similarity indices analysis (CoMSIA) techniques. The negative logarithm of IC (pIC) was used as the biological activity in the 3D-QSAR study. With the CoMFA model, the cross-validated value ( q) was 0.516, the non-cross-validated value ( R) was 0.927, and the external cross-validated value (Q) was 0.855; with the CoMSIA model, the corresponding q, R, and Q values were 0.538, 0.980, and 0.809, respectively. The CoMFA and CoMSIA models were validated by a structurally diversified test set of nine compounds. Then, molecular docking was carried out to better understand of the interactions between VEGFR-2 tyrosine kinase target and inhibitors. Finally, based on results of the structure-activity relationship and of the molecular docking, seven VEGFR-2 tyrosine kinase inhibitors that showed excellent potencies have been constructed. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the contribution of chromosomal anomalies and the frequency of particular types of aberrations in general couples preparing for pregnancy and make recommendations for pregnancy on the basis of the medical literature. Atotal of 6,198 general couples were included in the present study. The karyotypes were generated from the peripheral blood lymphocyte cultures and the cytogenetic analysis was performed using G-banding. In 12,396 cases, chromosomal anomalies were detected in 59 cases (0.48%, 59/12,396). Among of them, the frequency of translocation was 0.35% (n 5 43). Sex chromosomal anomalies accounted for 0.07% (n59), including Klinefelter syndrome (KS) (n54), Turner syndrome (TS) (n 5 4), and XYY syndrome (n 5 1). The others, including inversions (n 5 6) and deletion (n 5 1), accounted for 0.06%. Our study indicates that clinically important chromosomal defects are present at a remarkable frequency in the general couples in eastern China, suggesting pre-pregnancy cytogenetic analysis should be routinely performed among general couples in this area so that informed decision can be made, which will help to improve the quality of the pregnancy. [ABSTRACT FROM AUTHOR]

Carbon-based electrocatalysts are more durable and cost-effective than noble materials for the oxygen reduction reaction (ORR), which is an important process in energy conversion technologies. Heteroatoms are considered responsible for the excellent ORR performance in many carbon-based electrocatalysts. But whether an all-carbon electrocatalyst can effectively reduce oxygen is unknown. We subtly engineered the interfaces between planar graphene sheets and curved carbon nanotubes (G-CNT) and gained a remarkable activity/selectivity for ORR (larger current, and n 5 3.86, ~93% hydroxide + ~7% peroxide). This performance is close to that of Pt; and the durability is much better than Pt. We further demonstrate the application of this G-CNT hybrid as an all-carbon cathode catalyst for lithium oxygen batteries. We speculate that the high ORR activity of this G-CNT hybrid stems from the localized charge separation at the interface of the graphene and carbon nanotube, which results from the tunneling electron transfer due to the Fermi level mismatch on the planar and curved sp2 surfaces. Our result represents a conceptual breakthrough and pioneers the new avenues towards practical all-carbon electrocatalysis. [ABSTRACT FROM AUTHOR]

Peach lipid transfer protein (LTP1), Pru p 3.01, is a major allergen causing severe systemic reactions in peach allergic patients in Mediterranean countries and China. Significant expression variability has been reported among peach cultivars at both transcript and protein level. In this study, the allele diversity of the LTP1-encoding gene was assessed in a large set of peach cultivars by direct sequencing of the gene and its upstream region. Evolution of the LTP1-encoding genes in peach ( Prunus persica) and three other Prunus species ( Prunus kansuensis, Prunus mira, and Prunus davidiana) were also inferred. Sequence analysis revealed that LTP1-encoding genes are highly conserved among peach cultivars and wild peach. Three different allele sequences were obtained from 50 Prunus accessions on the basis of the upstream region of the LTP1-encoding gene and three allele specific markers were derived according to the polymorphic sites. These markers were used to test 316 peach cultivars, most of which clustered within the three main subpopulations of peach, 'Yu Lu', 'Hakuho' and landraces. The genotypic frequencies and allele frequencies in the oriental peach cultivars in these subpopulations except for 'Yu Lu' were found to be in Hardy-Weinberg equilibrium ( P < 0.05). The dominant alleles were upLTP1-a in the 'Yu Lu' subpopulation and upLTP1-c in the 'Hakuho' subpopulation, allele upLTP1-b and allele upLTP1-c had the highest rates in the landraces, and the dominant allele in the three peach wild relatives was allele upLTP1-b. Furthermore, we found many light-responsive elements in the upstream region. Most of the polymorphic sites in Prunus species are located in the intron region. Phylogenetic analysis suggests that Prunus kansuensis KC311794 and Prunus mira KC311791 are related more closely to Prunus persica KC311795 than to Prunus davidiana KC311792 and KC311793. The allele sequences we derived on the basis of this variability were distributed unevenly, indicating the need to study allergenicity in different subpopulations and the association between allele sequences and allergenicity. [ABSTRACT FROM AUTHOR]