Search

High energy storage density with low-energy loss polymer films are essential for high-performance electric devices. To avoid the high-energy loss of utilizing nonlinear polymer materials, a sandwich nanostructure comprising a linear polymer poly(methyl methacrylate) (PMMA) matrix embedded with a high dielectric constant BaTiO3 (BT) interlayer and poly(vinylidene fluoride) (PVDF) binder was constructed using a solution casting strategy. This structural design takes advantage of each component in the composite. The good dispersion of BT particles in the binder, which was incorporated between PMMA, enabled a high dielectric constant and fewer defects. Additionally, the excellent film formation ability of the PVDF binder guarantees the uniform thickness and stable structure of the BT mid-layer, and good miscibility between PVDF and PMMA enhanced the interaction between each layer. Interestingly, since the dielectric constant of PVDF was between BT fillers and PMMA, a dielectric gradient distribution mitigated the local electric field concentration, as proven by the simulation results. Consequently, a low-loss linear PMMA composite film exhibited satisfying breakdown strength and excellent discharged energy density, which were 25% and 460% higher than those of pristine PMMA, respectively.

Nanocomposite polymer materials are commonly used in energy storage devices on account of the excellent dielectric performance. However, there is a long-standing contradiction between dielectric constant and breakdown strength of nanocomposite. In this study, polyurea (PUA) is designed to in situ modify BaTiO3 (BT) nanoparticles. Based on the excellent dispersity, favorable compatibility and outstanding insulating performance of BT@PUA particles, the P(VDF-CTFE)/BT@PUA nanocomposite exhibits enhanced breakdown strength and reliability. In addition, the introduction of BT@PUA enhanced the dielectric constant to 10.72 and 35% larger than that of pure P(VDF-CTFE). As a result, the energy density of BT@PUA composite reaches 8.94 J/cm3, which is 1.65 times than P(VDF-CTFE) (5.41 J/cm3) and 4.5 times than the commercial biaxially oriented polypropylenes. Meanwhile, the quantified simulation illustrates the necessity of extremely high breakdown strength of the shell. Experiment results and simulation reveal that coating PUA is a novel and effective way to enhance energy storage performance for polymer nanocomposites with a promising broad application prospect.

The collective excitation of ordered spins, known as spin waves or magnons, can in principle radiate by emitting travelling photons to an open system when decaying to the ground state. However, in contrast to the electric dipoles, magnetic dipoles contributed by magnons are more isolated from electromagnetic environment with negligible radiation in the vacuum, limiting their application in coherent communication by photons. Recently, strong interaction between cavity standing-wave photons and magnons has been reported, indicating the possible manipulation of magnon radiation via tailoring photon states. Here, with loading an yttrium iron garnet sphere in a one-dimensional circular waveguide cavity in the presence of both travelling and standing photon modes, we demonstrate an efficient photon emissions from magnon and a significant magnon radiative damping with radiation rate found to be proportional to the local density of states (LDOS) of photon. By modulating the LDOS including its magnitude and/or polarization, we can flexibly tune the photon emission and magnon radiative damping on demand. Our findings provide a general way in manipulating photon emission from magnon radiation for harnessing energy and angular momentum generation, transfer and storage modulated by magnon in the cavity and waveguide electrodynamics., Comment: 9+7 pages, 4+2 figures

To analyze the components of proteins fromTheThe

The application prospects of dielectric materials such as polyvinylidene fluoride polymers in the field of energy storage have stimulated extensive research, and the performances are mainly affected by crystallization. However, most of them are focused on the influences of single-layer crystalline rather than macroscopic structures. In this study, a unique sandwich structure is proposed by combining layer-by-layer casting and multi-step thermal processing methods to control the macroscopic crystallization in each layer. Four heating temperatures were first set, and it was found that as the drying temperature increases, the films present different crystallization, which results in different dielectric performances. According to this feature, a sandwich structure was proposed for modification of macroscopic crystallization and the influences on energy storage performance were studied. After macroscopic modification of the crystallization, a low loss [Formula: see text], high energy density (7.12[Formula: see text]J/cc) with the highest charge-discharging efficiency was obtained, which presents the advantages of this methods, and the related mechanisms were discussed.

Choroidal thinning is an important feature of high myopia and has a negative correlation with the degree of myopia. However, due to the limitations of choroidal imaging, specific changes in choroidal thickness and vasculature are unclear. In recent years, the development of optical coherence tomography technology and optical coherence tomography angiography technology has made it possible to solve the problem. Emergence of biomarkers that objectively quantify choroidal thickness and vascular changes will help us understand the pathogenesis of high myopia and provide new ideas for the prognosis and treatment of myopia. In this review, in order to provide reference for clinical work, we summarize recent advances in the application of the two technologies in observing morphological changes of the choroid in high myopia and discuss the problems and prospects when they are combined with artificial intelligence for choroidal imaging.脉络膜变薄是高度近视眼的重要特征之一，且与近视程度相关。但因脉络膜显像技术具有局限性，有关脉络膜厚度及微血管系统改变的具体特征尚不清楚。近年来相干光层析成像术（OCT）和相干光层析血管成像术（OCTA）发展以及脉络膜厚度和微血管变化客观量化指标出现，有助于临床进一步探讨高度近视眼的发病机制，进而为治疗近视眼并评估预后提供新途径。本文综述近年来OCT和OCTA在高度近视眼脉络膜形态学改变研究中的应用及进展，并讨论其与人工智能相结合进行脉络膜显像时存在的问题与发展前景，以期为临床开展相关工作提供参考。

In this paper, mechanical properties, scanning electron microscopy, electron backscatter diffraction (EBSD),X ray diffraction (XRD) and transmission electron microscopy (TEM)techniques were combined to investigate the performance and microstructure of TC4 titanium alloy subjected to sole deep cryogenic treatment (DCT) and coupled static magnetic field and deep cryogenic treatment (MDCT) with different processing time. It showed that both the DCT and MDCT samples arrived at the optimal properties when the processing time was 12 h, and the tensile strength and elongation of the DCT12 sample increased by 2.57% and 8.06% respectively in comparison to the untreated sample, while that of MDCT12 sample increased by 3.01% and 11.29%. In DCT samples, the (110) crystal plane has transformed toward (100) and (101). However, the (002) crystal plane of MDCT sample showed the preferred orientation. In addition, the EBSD results showed that both the sole DCT and MDCT promoted the transformation of α→β in titanium alloy, and sole DCT weakened the texture of {0001} direction, while MDCT strengthened it. The change of microstructure was attributed to the grain rotation caused by the effect of cold compression force and magnetic driving force. TEM images revealed that the dislocation density of the DCT sample increased obviously in comparison to the untreated sample, together with the apparent tangling. As for the MDCT sample, the dislocation density increased further, nevertheless, the tangling phenomenon decreased to some extent and the distribution tended to be well-aligned.

In order to achieve high strength and high ductility, 2 vol.% ZrB2/2024Al nanocomposite with a quasi-network reinforcement distribution was designed and prepared by a combination of direct melt reaction and T6 heat treatment. The microstructural evolution shows that the in situ ZrB2 nanoparticles were self-assembled into clusters that were pushed towards α-Al boundaries and formed a quasi-network architecture; T6 heat treatment effectively eliminated interference of the coexisting eutectics. As expected, the unique heterogeneous structure results in a remarkable increase in the tensile modulus, strength and ductility of as-fabricated composite as compared with the matrix alloy. The superior strengthening effect can be attributed to the novel quasi-network architecture, matrix grain refinement and excellent load-bearing capacity, while the ductility enhancement can be ascribed to the matrix grain refinement and high damage tolerance of ZrB2 nanoparticle clusters.

Aberrant apoptosis of nucleus pulposus cells (NPCs) is one of the most remarkable pathological changes in intervertebral disc degeneration (IDD) development. Albeit the advances in the application of stem cell-based therapy in IDD treatment, the molecular mechanisms underlying the anti-apoptotic actions of mesenchymal stem cell (MSC) remain poorly elucidated.The expression patterns of apoptosis-related proteins and Wnt/β-catenin-related genes in NP samples isolated from patients with mild or severe IDD were compared by performing immunoblot assay and quantitative real-time polymerase chain reaction (qRT-PCR), respectively. NPCs were in vitro treated with compression to induce apoptosis and then co-cultured with Wharton's Jelly-derived MSCs without direct interaction. After that, flow cytometry was carried out to detect the apoptosis rate of NPCs and the activity of Wnt/β-catenin pathway was determined. DKK-1 was used to inhibit Wnt signaling, in prior to evaluation of the effects of WJ-MSCs on apoptosis within the co-cultured NPCs.Compared to the mild IDD group, there was a significant increase in the expression of Caspase-3 and Bax in the NP tissues from severe IDD patients, whereas Bcl-2 displayed an opposite result. In addition, the expression of Wnt 3a, Wnt 5a, Wnt 10a, GSK-3β, cyclinD1 and β-catenin was notably augmented in parallel with IDD progression. After compression treatment, the proportion of apoptotic NPCs was increased, which was then dramatically reversed by WJ-MSCs co-culture. Likewise, WJ-MSCs suppressed compression-induced Wnt-related gene expression and blocking Wnt/β-catenin pathway using DKK-1 enhanced the anti-apoptotic impacts of WJ-MSCs. In the presence of DKK-1, there was no significant difference between NPCs co-cultured with WJ-MSCs and those cells cultured alone.WJ-MSCs attenuate the compression-induced apoptosis in NPCs and inhibit the activation of Wnt/β-catenin signaling. Blocking Wnt/β-catenin pathway further facilitates the actions of WJ-MSCs in anti-apoptosis, indicating that Wnt/β-catenin signaling plays a crucial role in this process and may function as a potential therapeutic target for IDD treatment.

The current research on the characteristics of clay minerals in oil-sand reservoirs of China is still in its infancy. The burial depth of oil sands in the western slope of the Songliao basin is relatively shallow, and the reservoir contains clay minerals. Scanning electron microscope observations and X-ray diffraction analysis were used to test the chemical composition and characteristics of clay minerals. Comprehensive analysis and further research found that the clay mineral content of the oil-sand reservoir was relatively low and the clay minerals belonged to the illite–montmorillonite mixed-layer, composed of montmorillonite and illite, with occasional kaolinite, but no chlorite. The oil-bearing property of the oil-sand reservoir was consistent with the type of clay mineral found. The reservoir containing a mixed layer of illite–montmorillonite has a relatively good oil-bearing potential, and the oil content ranged from 3.80% to 16.17%.

High performance dielectric polymer materials are a key point for energy storage capacitors, especially film capacitors. In this paper, a sandwich-structured polymer film is constructed to achieve high energy density and high efficiency. High dielectric materials of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) doped with barium titanate (BaTiO3) are used as the outer layer to achieve a high dielectric constant, and a boron nitride nanosheet (BNNS) layer is inserted between P(VDF-HFP)/BaTiO3 to obtain a high breakdown field strength of composite films. The results indicate that when the doping amount of the BaTiO3 nanoparticles reaches 10 wt% and the mass fraction of the BNNS layer is 0.75 wt%, a significant improvement of energy storage performance is obtained. The energy storage density of the P(VDF-HFP)/BaTiO3/BNNSs composite film can reach 8.37 J cm−3, which is higher than 6.65 J cm−3 of the pure P(VDF-HFP) film. Compared with the P(VDF-HFP) film doped with BaTiO3, significant improvement of the breakdown field strength (about 148.5%) is achieved and the energy storage density increases 235% accordingly, resulting from the inserted BNNSs layer blocking the growth of electrical branches and suppressing leakage current. This novel sandwich-structured film shows promising future applications for high performance dielectric capacitors.

Most parts of China suffer often from haze pollution, which has a huge impact on human health. Road traffic has made the largest contribution to the haze. Of all the kinds of vehicular systems, the diesel engine produces the most PM; therefore, to reduce haze pollution, it is necessary research methods to reduce the PM produced by diesel engines. HHO (Brown's gas, Rhode's gas and HRG) is formed from H2 (60.79%) and O2 (30.39%) as well as a small amount of water vapour and active substances, such as oxygen radicals (O) and hydroxyl radicals (OH), which have quite strong oxidizing properties in the engine process, stimulating the C–H chain reaction during the combustion period and accelerating the oxidation of HC, CO and PM emissions as a result. The influence of blending HHO with diesel on diesel engine emission characteristics is well-researched, based on an 186FA single-cylinder diesel engine. The HHO was combined with air in the intake pipe. The influence of HHO on the amount of CO, HC, NO and PM emissions was analysed by collecting data under various speeds and loads. Through MOUDI, particles of various diameters under the highest torque working conditions and declared working conditions were collected to analyse how HHO affected the particle mass distribution in different diameter ranges. The analysis showed that when the speed was stable, the quantities of CO, HC and PM created were decreased by adding HHO; in addition, HHO had the greatest effect on PM. As the load increased, the amount of CO, HC and smoke declined gradually, but the decline of NO was smaller comparatively. Moreover, after blending with HHO, the quantity of NO created increased by 9.52% when the diesel engine operated according to external characteristics, and the quantity of HC, CO and PM created decreased by 31.6%, 11.3% and 20.71%, respectively. Finally, the gross mass of the particles dropped 67.48% and 42.53% under the highest torque working conditions and declared working conditions, respectively, with the distribution of diameters moving to smaller sizes. Introducing HHO into diesel can effectively reduce the generation of PM, which plays a positive role in reducing haze pollution.

The application prospects of dielectric materials such as poly(vinylidene fluoride) (PVDF) based polymers in the field of energy storage have stimulated extensive research. In this study, the energy storage characteristics of poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)) films crystallized from several solvents with different vapor pressure were investigated. The charge-discharge efficiency of the P (VDF-HFP) film crystallized from N, N-dimethylformamide (DMF) demonstrates an efficiency of 85% under an electric field of 1000 kV cm−1, which is 1.42 times of the film crystallized from dimethyl sulfoxide (DMSO). Meanwhile, the insulation resistivity of the film crystallized from DMF is also higher than other films, and the energy storage characteristics are optimal in this study. This work provides guidance for the preparation of PVDF-based polymer films using the solution method.

To investigate whether microRNA-615-3p participates in the development and progression of osteoarthritis by regulating chondrogenic differentiation of bone marrow mesenchymal stem cells.Bone marrow mesenchymal stem cells (BMSCs) were isolated from rat bone marrow and identified by flow cytometry. After chondrogenic differentiation was induced in BMSCs, expression levels of chondrogenic-specific genes were then detected by quantitate Real-time polymerase chain reaction (qRT-PCR). Expression levels of inflammatory cytokines were detected by enzyme-linked immunosorbent assay (ELISA). Protein expression of SOX9 after overexpression or knockdown of microRNA-615-3p was detected by Western blot, respectively.MicroRNA-615-3p was down-regulated in the process of chondrogenic differentiation of BMSCs. The mRNA expressions of chondrogenic-specific markers, COL2A1, COL10A1, ACAN and MATN3 were decreased after microRNA-615-3p overexpression in BMSCs. Overexpressed microRNA-615-3p down-regulated protein expression of SOX9. Expression levels of inflammatory cytokines, including interleukin-1 (IL-1), interleukin-6 (IL-6), interleukin-α (IL-α) were increased after overexpression of microRNA-615-3p, while inhibition of microRNA-615-3p expression obtained the opposite result. In addition, overexpression of SOX9 rescued the effect induced by microRNA-615-3p on inflammatory cytokines.MicroRNA-615-3p participates in the development and progression of osteoarthritis by increasing the expressions of inflammatory cytokines and inhibiting chondrogenic differentiation of BMSCs.

Digoxin is a kind of plant-derived cardiac glycoside that is mainly used to treat heart diseases, especially in congestive heart failure or arrhythmia. However, its potentiality presented in anti-tumor remains unexplored. The purpose of this study was designed to investigate the beneficial pharmacological activity of digoxin on breast cancer cell line (MDA-MB-231, MM231).The methyl thiazolyl tetrazolium (MTT) assay was utilized to detect the proliferation of the breast cancer MM231. The apoptotic cell numbers were determined by the flow cytometry analysis. The expressions of Bcl-2 (B-cell lymphoma-2) and Bax (Bcl2-associated X protein) were detected by Western blot analysis.Digoxin dose-dependently blocked the cell growth of the breast cancer MM231 through MTT assay, whereas the apoptotic numbers were significantly elevated as reflected in acridine orange staining and flow cytometry analysis. In addition, findings from Western blotting method indicated that digoxin intervention showed reduced Bcl-2 expression and elevated Bax level in MM231 cells, characterized by increased Bax/Bcl-2 ratio.Digoxin plays a potential anti-tumor role in breast cancer in vitro, possibly by inducing mitochondria-dependent apoptosis.

The Fulongquan Depression is a major production area for natural gas in the Songliao Basin. This study was based on geochemical analysis of source rocks. Our results indicate that the kerogen types are primarily type III. These rocks represent a source of gas in a highly mature stage. The basin was formed during two major events of tectonic subsidence and uplift between 144 and 95 Ma before present. These periods were followed by a stable sedimentary burial phase. In the Cretaceous fault period, processes of secondary hydrocarbon generation were present. Corresponding to the two major tectonic subsidence movements, there were two key hydrocarbon generation processes. Contingent on research on sedimentary facies, source rock thicknesses, and the distribution and intensity of hydrocarbon generation, the northern and southern parts of this depression represent favorable areas for the exploration and development of hydrocarbon extraction.

To investigate the expression of leukemia-related protein 16 (LRP16), proliferating cell nuclear antigen K-67 (Ki67) and epidermal growth factor receptor-1 (EGFR-1) in breast cancer tissue and to explore the correlation between the expression of those proteins and breast cancer clinical pathologic factors and prognosis.The expressions of LRP16, Ki67 and EGFR in breast cancer tissues of 86 cases were detected by the immunohistochemical method and the correlations between the expression of LRP16, Ki67 and EGFR and clinical pathologic factors and prognosis were investigated.Positive expression rates of LRP16, Ki67 and EGFR in breast cancer tissue were 52.3%, 70.9% and 16.3%, respectively. There was no statistical difference in the expression of RP16, Ki67 and EGFR between different age groups (p0.05). The expression of LRP16 was correlated with clinical stage, histological grade, tumor size and lymphatic metastasis (p0.05); the expression of Ki67 was correlated with clinical stage, histological grade, tumor size and lymphatic metastasis (p0.05); the expression of EGFR was correlated with histological grade (p0.05). Comparison of postoperative local recurrence and metastasis time between LRP 16 positive group and negative group showed statistically significant difference (p0.05); comparison of postoperative local recurrence and metastasis time between Ki67 positive group and negative group also showed statistically significant difference (p0.05); comparison of postoperative local recurrence and metastasis time between EGFR positive group and negative group showed no statistically significant difference (p0.05).Detection of expression levels of LPR16, Ki67 and EGFR in breast cancer tissue improves the understanding of biological behaviors of breast cancer, which in turn provide clinical guidance in diagnosis, treatment and prognosis assessment.

Dry sliding tests for steels were performed in air under the test temperature at 400 °C and the loads of 50–250 N. The wear behavior and characteristics were focused on to explore their general characters in severe conditions. The wear behavior of various steels presented a common wear regular pattern; a mild-to-severe wear transition occurred with an increase of the load. Because oxidative wear prevailed, this was suggested to call the mild-to-severe wear transition of oxidative wear. More importantly, a transition region in the oxidative wear was found to exist and corresponded to the different-extent plastic deformation of the subsurface substrate. Through reviewing the past research, the mild-to-severe wear transition of oxidative wear was noticed to be a popular phenomenon in dry sliding wear of severe conditions, particularly elevated-temperature. This transition (region) with oxidative-wear characteristics was considered to the essence of wear failure in severe conditions, which was a physical and chemical process including oxidation, thermally softening and plastic deformation of worn surfaces and subsurfaces. And the wear characteristics in the transition region were revealed.

To compare the clinical efficacy between calcar replacement arthroplasty and InterTan nail in treatment of intertrochanteric fractures in the aged.From January 2008 to July 2013, a total of 58 elderly patients with intertrochanterie fracture , had been treated in Department of Orthopaedics, Tianjin Occupational Diseases Control and Treatment Hospital, were retrospectively compared.Half of them were treated with calcar replacement arthroplasty and half with InterTan nails.In the calcar replacement arthroplasty group, there were 8 men and 21 women, with an average age of (85.3±4.9) years, there were 8 A1, 16 A2 and 5 A3 fractures according to the AO classification.In the InterTan nail group, there were 10 men and 19 women, with an average age of (86.1±5.6) years, there were 11 A1, 15 A2 and 3 A3 fractures according to the AO classification.The 2 groups were compared in terms of the duration of the operation, intraoperative blood loss, hospitalization time, time of off-bed activity, complications, mortality rate, Harris hip score, short form 36 questionnaire score and ADL score.Twenty-seven patients in the calcar replacement arthroplasty group and twenty-six patients in the patients in each group were followed up InterTan nail group were follow-up for a period of 24 months.There were no significant differences between the 2 groups regarding hospitalization time, complications, mortality rate, Harris hip score, short form 36 questionnaire score and ADL score(P0.05). However, the operative time, intraoperative blood loss, and the time of off-bed activity for the calcar replacement arthroplasty and InterTan nail groups was respectively (78±29) minutes vs (59±32) minutes, (316±185) ml vs (108±97) ml, and (15±5.8) days vs (32±12.7) days, all of them with a significant difierence(P0.05).The patients in the calcar replacement arthroplasty group suffered longer operative time and more blood loss, but they can obtain early off-bed activity.The hospitalization time, complications, mortality rate, hip function and quality of Life between the two were the same.

The salvage radiation or surgery is the main choice for recurrent nasopharyngeal cancer now. However the recurrent tumor becomes radiation insensitive and meanwhile,morbidity and mortality become higher.Recently the endoscopic salvage surgery has been developed;the collective evidence from a number of such studies suggests that endoscopic nasopharyngectomy is a safe and effective procedure for the treatment of rNPC.This article reviewed related researches about the feasibility,methods, and current situation of endoscopic salvage surgery.

The dry sliding wear tests of H13 steel were performed under atmospheric conditions under various ambient temperatures and loads; the wear performances and the wear mechanisms were studied. At room temperature (RT), the wear loss of the steel gradually increased with increasing the load. An adhesive wear prevailed with little tribo-oxides on the worn surfaces. Under the atmospheric conditions at 473 K (200 °C) and a load of 100 N or above, a mild oxidation wear prevailed with about 20-μm thickness of tribo-oxide layer forming on the asperities of worn surfaces. The wear loss first reduced and then slightly increased with increasing the load. Compared with the other ambient temperatures, the wear at 473 K (200 °C) retained the lowest wear loss due to the protection of the tribo-oxide layer. As the ambient temperature reached 673 K (400 °C), the wear loss increased with increasing load, leading to higher wear than those observed at RT and at 473 K (200 °C). The predominant wear mechanism at 673 K (400 °C) was oxidation wear, unlike mild oxidation wear, which dominated at 473 K (200 °C).

Based on the lubrication theory of mould flux, a mathematical model of dynamic pressure in mould flux channel was developed, and the distribution of dynamic pressure and its variation during non-sinusoidal oscillation were investigated. The effects of casting speed and non-sinusoidal oscillation parameters, including the degree of non-sinusoidal operation (non-sinusoidal factor), amplitude and frequency of oscillation on the dynamic pressure in the mould flux channel, were studied. The results indicate that the maximum negative pressure is decreased, and the maximum positive pressure is increased with increasing non-sinusoidal factor. The optimum value of non-sinusoidal factor is ∼0·2. With increasing amplitude and frequency of oscillation, both the negative and positive pressure are increased; moreover, the increment of positive pressure is obviously greater than that of negative pressure; especially when the oscillation frequency is increased, the increment of negative pressure is very little. W...

The dry sliding wear tests were performed for AZ91D alloy under the loads of 12.5–300 N and the ambient temperatures of 25–200 °C. We studied the wear characteristics of AZ91D alloy as a function of the normal load and the ambient temperature. The mild-to-severe wear transition occurred with increasing the load and the critical load reduced with the ambient temperature rising. However, no matter how high the ambient temperature was in the range of 25–200 °C, the mild wear prevailed under the lower loads. Especially, the AZ91D alloy presented a lower wear rate at 200 °C than at 25 and 100 °C under the low loads of 12.5–25 N, but vice versa under the loads of more than 25 N. These phenomena seem to be contradictory to the popular view that the mild-to-severe wear transition is controlled by the critical surface temperature. These may be attributed to a thick and hard mechanical mixing layer (MML) containing the mixture of MgAl2O4 and Mg on the worn surface. The MML thickened with increasing the ambient temperature (under the low loads), effectively reduced wear and markedly elevated the critical surface temperature. The oxidative wear and delamination wear successively predominated in the mild wear regime; the gross plastic-induced wear would prevail in the severe wear regime.

The sliding wear tests were performed under the atmospheric conditions at 400 °C for H13 steel. The effects of load on the wear mechanisms and delamination patterns were studied. A new delamination pattern was found to appear in the mild-severe transition region of the elevated-temperature wear. The delamination pattern could be proved by the belt-like debris and the corresponding wide ditches on worn surfaces. Under the loads of 50–100 N, mild oxidative wear prevailed with the characteristics of the plate-like oxide debris and low wear loss and its delamination was from inside oxides or the interface between the oxides and bulk metal. The wear rate increased with increasing load; the mild–severe wear transitions occurred under the loads of 100–200 N concomitant with more and more belt-like debris and wide ditches on worn surfaces. In this case, the wear loss would be mainly attributed to a special delamination from inside the bulk metal underneath the tribo-oxides with the formation of belt-like debris containing oxide and bulk metal. The delamination pattern was realized by the way that the ploughed furrows were first formed by the micro-cutting of oxide particles in the delaminated zone, whereby cracks initiate from the furrow wall and propagate parallel to worn surface to cause the delamination.

The A356 alloy and Zr(CO3)2 components are used to fabricate the in situ Al3Zr, Al2O3 particles reinforced A356 aluminum alloy matrix composites by direct melt reaction method. The average particle sizes are in the range of 1–2 μm. The composite melt is cast by permanent mould (composite A) and squeeze casting (composite B). In composite B the conventional casting defects are less and the grains are finer than those in composites A. The casting process has little apparent effect on the granularity of particles. The tensile strength and elongation of composite B is 345 MPa and 15.07%, respectively, which are enhanced by 1.6 and 2.15 times than those of composite A. The abradability and corrosion resistance are also improved obviously. The better properties including tensile, abradability and corrosion resistance of composite B are attributed to the high density and finer grain of matrix via squeeze casting.

K-shell X-ray emission was observed in the neutralization process of Ar16+ interacting with beryllium and molybdenum at slow speed (less than Bohr velocity). The K-shell X-ray emission came from the metastable component of Ar16+ beam with the configuration (1s2s) produced from electron cyclotron resonance ion source. The intensity ratio of Kβ X-ray emission to Kα X-ray emission (IKβ/IKα) in the neutralization process decreased when the kinetic energy of the projectile increased. This is closely related to the flight time the projectiles spend above the surface, which is dominated by both the work function of the metal and the normal velocity component of the incident ions to the surface according to the classical over-barrier model. As the relation between IKβ/IKα and the above-flight time shows, the longer time above the surface the larger ratio due to the above-surface contribution. Furthermore, the smaller work function leads to the smaller contribution from the above surface.

In situ (Al 2 O 3 + Al 3 Zr) np /Al nanocomposites were successfully prepared by magneto-chemical melt reaction from Al–Zr(CO 3 ) 2 system. The solidification microstructure and mechanical properties are investigated. Results indicate that the size of majority in situ α-Al 2 O 3 and Al 3 Zr particles is about 80 nm, and the nano-sized particles are well distributed in the aluminum matrix. The ultimate tensile strength and yield strength of the nanocomposites are enhanced with the increasing of particulate volume fraction, and are markedly higher than that of (Al 2 O 3 + Al 3 Zr) p /Al composites synthesized under zero magnetic field. When the particulate volume fraction is 8%, The ultimate tensile strength σ uts , yield strength σ y , elongation δ and Vickers hardness of the (Al 2 O 3 + Al 3 Zr) np /Al nanocomposites are 326.7 MPa, 245.6 MPa, 18.6% and 125, respectively. The principal strengthening mechanism for (Al 2 O 3 + Al 3 Zr)np/Al nanocomposites may include Orowan strengthening, Grain-refined strengthening, Solid–solution strengthening and Dislocation strengthening.

A method of filtering based on empirical mode decomposition (EMD) for coulostatically induced transients (CITs) is presented. This filtering was illustrated using CIT and its associated impedance spectra, and comparisons have been made with wavelet filtering and the finite impulse response (FIR) method. The results reported here demonstrate that EMD filtering is applicable to coulostatic measurements data in both the time and frequency domains, where wavelet filtering can also be successful. Moreover, in cases where the noise needs to be filtered from the nonlinear CITs, EMD can eliminate noisy data from CIT. The proposed method shows superior performance over the traditional methods and is an alternative filtering method for the CIT analysis.

A new in situ Al–Zr–O–B system is exploited. The Al–Zr(CO3)2–KBF4 components are used to fabricate the particle reinforced aluminum matrix composites by the direct melt reaction method. The analytical results of XRD and SEM show that the in situ endogenetic particles are ZrAl3, ZrB2 and Al2O3, which are well distributed in the aluminum matrix. The sizes of reinforced particles are 0.5–2.5 μm. The results of mechanical properties of the composites show that the tensile strength and yield strength are improved with the increase of theoretical volume fraction of particles in matrix in the range of 0–12%, which are much superior to those of aluminum matrix. The best elongation of composites is 33% when the theoretical volume fraction is 3%. The fracture mechanism belongs to a ductile one. The wear resistance properties of the composites are much higher than that of aluminum matrix. The best abradability is got when the theoretical volume fraction of particles is 6%. The wear mechanism of the aluminum matrix is adhesive wear while the wear mechanism of (ZrAl3 + ZrB2 + Al2O3)p/Al composites is abrasive wear.

Learning points for clinicians The utility of electrocardiogram (ECG) in the diagnosis of coronary artery occlusion plays an essential role in the American College of Cardiology (ACC) / American Heart Association (AHA) guidelines for either ST-segment elevation myocardial infarction (STEMI) or non-STEMI. However, upsloping ST segment depression and tall T waves together indicate a non-classical ECG of proximal left anterior descending (LAD) coronary artery occlusion. A 31-year-old male was admitted to the emergency room (ER) presenting chest tightness accompanied with nausea and vomiting. He was a non-smoker and had neither significant past history of diabetes, hypertension or hyperlipidemia nor any family history of coronary artery disease. His symptoms lasted for 1 h with no alleviation. Admission electrocardiograms (ECGs) were performed in the ER (Figure 1). In …

Based on atomistic simulations, the elastic moduli and vibration behaviors of fivefold twinned copper nanowires are investigated in this paper. Simulation results show that the elastic (i.e., Young's and shear) moduli exhibit size dependence due to the surface effect. The effective Young's modulus is found to decrease slightly whereas the effective shear modulus increases slightly with the increase in the wire radius. Both moduli tend to approach certain values at a larger radius and can be suitably described by core-shell composite structure models. Furthermore, we show by comparing simulation results and continuum predictions that, provided the effective Young's and shear moduli are used, classic elastic theory can be applied to describe the small-amplitude vibration of fivefold twinned copper nanowires. Moreover, for the transverse vibration, the Timoshenko beam model is more suitable because shear deformation becomes apparent.

The effect of injectable demineralized bone matrix (DBM) on bone repair is not known. Here, we tested the hypothesis that injectable DBM can heal a critical-size diaphyseal radius defect in a rabbit model.The bone defect was filled with DBM powder, injectable DBM or powdered, freeze-dried powdered allografts. Radiological determination, gross evaluation, histology, and micro-computer tomography was carried out 4, 8, and 12 weeks after the surgery, respectively.The injectable DBM group yielded better when compared with the freeze-dried powder group (p0.05). Moreover, biomechanical functionality was restored comparable to normal levels in the injectable DBM group.The injectable DBM was as effective in structurally and functionally repairing bone defects as the DBM powder and more effective than the freeze-dried bone powder. Thus, our study supports the use of injectable DBM for bone healing.

2-Deoxyglucose (2-DG; 10 mM) replacing glucose for ∼15 min regularly causes a very sustained enhancement of synaptic transmission in the CA1 hippocampal zone (2-DG-induced long-term potentiation, 2-DG-LTP). This LTP is prevented by dantrolene (10μM) or by the NMDA antagonist aminophosphonovalerate (APV; 50–100 μM); it is Ca-dependent [1, 2], and is not depressed by adenosine antagonists (DPCPX and 8-SPT), which prevent the initial block of EPSP caused by 2-DG, but is not observed if glucose is replaced by sucrose instead of 2-DG. To clarify the role of [Ca]i, in 2-DG-LTP, we monitored fluo-3 fluorescence inCA1 neurons, in submerged slices kept at 30°C. 2-DG applied as above consistently led to a rapid, but reversible rise in fluorescece. Isomodar sucrose (for 15–40 min) elicited smaller, but significant increases in fluorescence. Dantrolene and APV greatly reduced 2-DG's effect, but Ca-free medium did not abolish it. Paradoxically, it was fully suppressed by 8-SPT, but not at all by DPCPX. The discrepancies between the effects of sucrose and 8-SPT on the fluorescence changes and on 2-DG-LTP suggest that the observed increases in the postsynaptic [Ca] i are not essential for 2-DG-LTP. In further experiments, intracellular recordings showed that 2-DG applications consistently hyperpolarizeCA1 neurons, probably owing to adenosine-mediated activation of K+ conductance (which could be prevented by DPCPX or 8-SPT, but not by a KATP antagonist, glyburide). The 2-DG-LTP of EPSP was not suppressed by EGTA leakage from electrodes, in keeping with the above evidence that the [Ca] i changes needed for the induction of 2-DG-LTP are not those observed postsynaptically. In this respect, as well as in the absence of postsynaptic depolarization, 2-DG-LTP offers a marked contrast to more conventional forms of LTP.

Temporary block of glycolysis by 2-deoxy-D-glucose (2-DG) reversibly suppresses synaptic transmission in the CA1 region of hippocampal slices. Recovery of responses is followed by a sustained potentiation of field excitatory postsynaptic potentials (EPSPs) (2-DG-LTP). To investigate the mechanisms involved in this type of LTP, we studied the effects of 2-DG on membrane properties of CA1 neurons (in slices from SpraguenDawley rats), recorded with sharp intracellular electrodes containing 3 M KCl, as well as patch electrodes, filled mainly with 150 mM KMeSO4 and Hepes. The predominant change produced by 15- to 20-min applications of 2-DG (10 mM, replacing glucose) was hyperpolarization (n5.6 ± 1.1 mV for 18 intracellular recordings and n7.2 ± 0.80 mV for 17 whole-cell recordings) accompanied by a fall in resistance (n33 ± 2.5% for 14 intracellular recordings and n11.6 ± 7.1% for 15 whole-cell recordings). Virtually identical hyperpolarizations were recorded in the presence of 20 μM glyburide (n5.5 ± 1.5 mV, n = 6), but they were abolished by adenosine antagonists 8-(p-sulfophenyl)theophylline (8-SPT) and 8-cyclopentyl-3,7-dihydro-1,3-dipropyl-1H-purine-2,6- dione (DPCPX) (2.8 ± 1.6 and 4.0 ± 1.7 mV, respectively; n = 5 for both). It was concluded that the hyperpolarization is most likely caused by an increase in K + conductance, activated by a 2-DG-induced rise in adenosine release. After such applications of 2-DG, a sustained potentiation of EPSPs (similar to the 2-DG-LTP of field EPSPs) was evident in five neurons recorded with intracellular electrodes but not in any of nine whole-cell recordings, where it was replaced by sustained, LTD-like depression. We conclude that a factor essential for 2-DG-LTP induction is lost during whole-cell recording.